JP2002301660A - Polishing temperature measurement method, polishing method, workpiece holding mechanism and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly measure a polishing temperature while polishing a workpiece. SOLUTION: This workpiece holding mechanism 10 for holding the workpiece 3 in a plane vertical to a pressing direction is provided with a cylindrical shaft part 12, a plate member 14 having an infrared-ray transmitting part 16, and a lip seal 18 positioned on the back face of a peripheral part of the workpiece. The workpiece 3 is pressed against a polishing pad 28 by the pressure of a fluid fed to a space part 31 formed by the plate member, the lip seal and the workpiece. The workpiece is polished by relatively moving the workpiece with respect to the polishing pad with the workpiece pressed against the polishing pad. At least two infrared rays having different wavelengths or wavelength regions are extracted by using optical filters 38a and 38b, and the radiant quantity of the infrared ray of each wavelength or wavelength region is measured by using an infrared radiation ray thermometer 30 disposed above the shaft part, and the measured radiant quantity is arithmetically processed by an arithmetic processing device 40, so that the temperature of the polished surface of the workpiece is found.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a polishing temperature when polishing a workpiece such as a semiconductor wafer, a glass substrate and an electronic component while moving the workpiece relative to a polishing pad. The present invention relates to a method of polishing a work while polishing, a method of measuring a polishing temperature of the work, and a work holding mechanism and a polishing apparatus suitable for use in performing the polishing method.

[0002]

2. Description of the Related Art In a process of forming a laminated wiring on a surface of a semiconductor wafer, it is general to polish and flatten a surface of an intermediate insulating layer formed on a circuit including a wiring and the like. In general, a metal film is formed on the surface of the substrate on which the groove is formed, and is polished and flattened to remove a metal other than the metal in the groove. In these polishing processes, it is required to uniformly polish the surface to be polished (also referred to as a “surface to be polished” or “surface to be processed” or simply “surface”).

Generally, a work such as a semiconductor wafer is polished while being pressed against a polishing pad. When the work is pressed against the polishing pad, pressure is applied to the work and the polishing pad. In this specification, this pressure is referred to as a processing pressure.

[0004] One of the conditions to be considered when uniformly polishing the work surface as described above is a polishing temperature. The polishing temperature, during polishing, the workpiece relatively moves with respect to the polishing pad, and when the polished surface of the workpiece is sliding on the polishing surface of the polishing pad, the contact surface between the workpiece and the polishing pad This is the temperature of the work and the polishing pad. The temperature of the work and the polishing pad at the contact surface between the work and the polishing pad is usually approximately the same. Therefore, the polishing temperature can be obtained by measuring one of the temperature of the polished surface of the work and the temperature of the polished surface of the polishing pad at the portion where the work and the polishing pad are in contact. Generally, the temperature of the work and the polishing pad at the contact surface between the work and the polishing pad (ie, the polishing temperature)
During polishing, the temperature of the polishing pad is higher than any of the temperature of the portion of the polishing pad that is not in contact with the work, the surface plate for mounting the polishing pad, and the holding mechanism that holds the work. The polishing temperature is mainly determined by frictional heat generated during polishing.

The polishing temperature is, in particular, chemical mechanical polishing (Chemical mechanical polishing).
This is an important factor that determines the quality of polishing in the mechanical polishing (CMP) method.
The CMP method is polishing performed by utilizing the fact that a polishing liquid chemically reacts with a work on a surface to be processed. In order to perform polishing uniformly by the CMP method, it is necessary to stably advance a chemical reaction between the polishing liquid and the work. For this purpose, it is preferable to maintain the polishing temperature within a predetermined range.

[0006] In order to maintain the polishing temperature within a predetermined range, it is first important to correctly measure the polishing temperature during polishing. Therefore, a method of measuring the temperature of a work or a polishing pad during polishing has been proposed in advance. For example, Japanese Patent Application Laid-Open No. 8-78369 discloses that a temperature detecting means such as a thermocouple or an infrared temperature detector is provided at or near a part of a work to detect a change in polishing temperature. Japanese Patent Application Laid-Open No. 9-123057 discloses that a temperature measuring device for measuring the surface temperature of a plurality of portions of a polishing pad is provided.

[0007]

However, these conventional methods for measuring the polishing temperature by the conventional method cannot be said to be methods for accurately measuring the polishing temperature for the following reasons.

For example, when measuring temperature using a thermocouple, a measurement error occurs due to the state of contact of the thermocouple with the temperature measuring object and the heat capacity of the thermocouple, so that it is difficult to accurately measure the polishing temperature. is there. Further, JP-A-8-78
In the method described in JP-A-369-369, what is measured by the thermocouple is the temperature of the “back surface” of the work, not the surface temperature of the work, that is, the “polishing temperature”.

Further, if the temperature detecting means is provided in a part of or near the work as in the method described in Japanese Patent Application Laid-Open No. 8-78369, the processing pressure at the part where the temperature detecting means and the work are in contact with each other is reduced. Unlike the part, a uniform processing pressure distribution may not be obtained. If the processing pressure distribution is not uniform, the work surface cannot be uniformly processed over the entire surface. As a result, for example, the yield of the work is reduced. To avoid such inconvenience, it is effective to reduce the area of the temperature detection unit. However, the smaller the area of the temperature detector, the lower the measurement accuracy and the more difficult it is to accurately detect the temperature. Therefore, there is a limit to reducing the area of the temperature detector.

Japanese Patent Application Laid-Open No. 8-78369 refers to detecting the surface temperature of a polishing pad using an infrared temperature detector. However, the publication does not specifically disclose a temperature detection method performed using an infrared temperature detector.

On the other hand, according to the method described in Japanese Patent Application Laid-Open No. Hei 9-123057, the temperature of the surface of the polishing pad can be measured without bringing the temperature detecting means into direct contact with the surface of the polishing pad. However, Japanese Patent Laid-Open No. 9-1230
The portion measured according to the method described in Japanese Patent No. 57 is a portion where the polishing pad is exposed, not a polishing surface of the polishing pad in contact with the workpiece. The temperature of the exposed portion of the polishing pad is a temperature measured after the work is polished (slid) at the portion. In other words, the temperature measured at that portion is the temperature measured on the polishing surface of the polishing pad in a slightly “cooled” state after the work has left the polishing pad, and the polishing temperature defined earlier is accurately measured. Not shown.

As described above, it is difficult to accurately measure the polishing temperature by using any of the conventional polishing temperature measuring methods. To solve these problems, for example,
A correlation between the polishing temperature measured according to the above method and the polishing amount of the work is obtained, and the polishing rate (the polishing amount per unit time) is corrected based on the correlation. Such a correlation can be applied only to a specific processing lot (specific combination of a polishing pad and a work), and needs to be obtained every time the processing lot changes. The work required to determine this correlation is one factor that reduces the efficiency of the polishing process, and it has been desired in advance to eliminate this work or reduce the time required for this work.

The present invention has been made in view of the above circumstances, and a polishing temperature measuring method for more accurately measuring a polishing temperature during polishing without affecting a processing pressure, and a method for implementing the polishing temperature measuring method. Provided are a work holding mechanism that is preferably used when polishing, a polishing method that can polish a work while accurately measuring a polishing temperature during polishing, and a polishing apparatus that is preferably used when performing the polishing method. Make it an issue.

[0014]

In order to solve the above problems, according to a first aspect, the present invention provides a method of polishing a work surface by moving the work relatively to the polishing pad while pressing the work against the polishing pad. At this time, infrared light of at least two different wavelengths or wavelength ranges, the amount of which changes according to the temperature of the surface to be polished of the work, is taken out at the back side of the central portion of the work, and each taken out wavelength or Provided is a polishing temperature measuring method for measuring a radiation amount of infrared light in a wavelength range in a non-contact manner and measuring a temperature of a surface to be polished of a work from an infrared radiation amount in each wavelength or wavelength range.

According to a second aspect of the present invention, there is provided a polishing method for polishing a work surface by moving the work relatively to the polishing pad while pressing the work against the polishing pad, wherein the polishing method comprises at least two different wavelengths. Alternatively, infrared light in a wavelength range, the amount of which varies depending on the temperature of the surface to be polished of the work, is extracted at the back side of the central portion of the work, and the amount of infrared light of each extracted wavelength or wavelength range is extracted. Is measured in a non-contact manner, and the workpiece is polished while measuring the polishing temperature from the amount of infrared radiation of each wavelength or wavelength range. This polishing method is based on the first
Is a polishing method using the polishing temperature measuring method of the present invention provided in the gist of the present invention.

According to a third aspect, the present invention is a work holding mechanism for pressing a work against a polishing pad and holding the work in a plane perpendicular to the pressing direction, the work holding mechanism comprising a cylindrical shaft portion, an infrared transmitting portion, And a lip seal attached to the plate member so as to be located on the back surface of the peripheral portion of the work, and when the work is held, a space is formed by the plate member, the lip seal and the work, A work holding mechanism characterized in that a work is pressed against a polishing pad by the pressure of a fluid supplied to a space. This work holding mechanism is suitable for carrying out the polishing temperature measuring method and the polishing method of the present invention.

According to a fourth aspect of the present invention, there is provided an apparatus for polishing a surface to be polished of a work with a polishing pad, the infrared light having at least two different wavelengths or wavelength ranges taken out on the back side of the center of the work. The present invention provides a polishing apparatus having a unit capable of measuring the amount of radiation. Specifically, such a polishing apparatus includes: (a) the work holding mechanism according to the third aspect; (b) an optical filter having at least two different transmission wavelength bands, and a switch of the optical filter; and (c) an optical filter. (D) a platen supporting the polishing pad; and (e) means for moving the work relative to the polishing pad. It is a polishing device.

Alternatively, such a polishing apparatus includes: (a) the work holding mechanism according to the third aspect; (b) a wavelength-selective reflector disposed on the back surface side of the central portion of the work; (D) a platen for supporting a polishing pad; and (e) a work relative to the polishing pad. This is a polishing apparatus having means for moving the polishing apparatus.

Hereinafter, each invention provided in the first to fourth aspects will be described. In the polishing temperature measurement method provided in the first aspect, when the work is moved relative to the polishing pad and the work surface is polished, infrared rays of at least two different wavelengths or wavelength ranges are applied to a central portion of the work. This is a method in which the temperature of the polished surface of the work is measured by measuring the radiation amount (that is, the energy amount) of the extracted infrared light of each wavelength or wavelength region in a non-contact manner on the back surface side.

In the present invention, the temperature of the surface to be polished of the work is measured as the polishing temperature. However, the term “work surface to be polished” may be used to refer to the vicinity of the surface to be polished including a portion from the surface to be polished to a certain depth.
For example, when the work is a semiconductor wafer having a wiring of Cu or the like formed on the surface, the polishing temperature measured by the polishing temperature measuring method of the present invention is, as will be described later, strictly speaking, the bottom surface of the wiring is located. May be the temperature of the part. Such a temperature is also included in the polishing temperature measured in the present invention.

The "work" is generally a plate-like body in which at least one of two surfaces is flattened by polishing. The work is, specifically, a semiconductor wafer, a glass substrate, an electronic component, or the like. The “back surface” of the work refers to a surface facing the front surface when the polished surface of the work is the front surface, and is also referred to as a “back surface”.

In the method for measuring a polishing temperature of a workpiece according to the present invention, infrared rays of at least two different wavelengths or wavelength ranges are selected and extracted as described later, and the radiation amount (ie, energy amount) of each extracted infrared ray is measured. I do. The amount of infrared radiation is measured without contact. That is, the amount of infrared radiation is
The device for measuring the amount of infrared radiation is measured without contacting the object. When measuring infrared radiation without contact,
Since the infrared radiation measuring device does not contact the work and the polishing pad, the polishing temperature can be measured without affecting the processing pressure. When the temperature is determined based on the amount of infrared radiation measured in a non-contact manner, there is an advantage that a measurement error due to the heat capacity of the measuring instrument does not occur. Further, when the temperature is determined by measuring the amount of infrared radiation, the temperature is determined from the amount of energy of infrared rays emitted from a measurement area having a predetermined area during a predetermined time. Therefore, for example, the polishing temperature can be measured more accurately than when the local temperature at a certain moment is measured using a thermocouple.

Measuring temperature from the amount of infrared radiation
Generally, one suitable wavelength or wavelength range λx is selected, and λ
The measurement is performed by measuring the amount of infrared radiation of x with an infrared radiation amount measuring device and obtaining the temperature from the measured radiation amount.
Usually, while polishing is being performed, the infrared ray of λx can be radiated also from a portion other than the surface to be polished of the work (for example, a member or an element constituting the polishing apparatus). Therefore, when measuring the temperature by measuring the amount of infrared radiation of one wavelength or wavelength range λx, the measured temperature may be affected by the λx infrared radiation radiated from the part other than the surface to be polished of the work. And the polishing temperature is not always accurate.

As one method for obtaining an accurate polishing temperature, the amount of λx infrared radiation radiated from a portion other than the surface to be polished of a work is previously determined as a background, and the background is determined from the amount of radiation measured during polishing. There is a method of correcting the measured radiation amount by subtraction.
However, if the temperature of a portion other than the surface to be polished of the workpiece changes during the polishing, the radiation amount cannot be corrected correctly even if the background obtained in the unpolished state is used.

Further, during the polishing, the radiation amount of the infrared ray of λx radiated from the surface to be polished of the work and the radiation amount of the infrared ray of λx radiated from the portion other than the surface to be polished of the work are measured separately. Can not. Therefore, in the polishing temperature measuring method of the present invention, at least two different wavelengths or wavelength ranges in which the radiation amount changes from infrared rays of various wavelengths that can be detected on the back surface side of the work in accordance with the temperature of the polished surface of the work. The infrared radiation of each wavelength or wavelength range is measured, and the polishing temperature is determined from the measured radiation. This makes it possible to eliminate or reduce the influence of infrared rays radiated from portions other than the surface to be polished of the work, and to measure the polishing temperature with higher accuracy. Hereinafter, a specific method for determining the polishing temperature from the amount of infrared radiation of two different wavelengths or wavelength ranges will be described.

A first method for determining the polishing temperature from the amount of infrared radiation of two different wavelengths or wavelength ranges is as follows: 1) At least two different wavelengths or wavelength ranges of infrared light are emitted; The infrared ray A having a wavelength or a wavelength range from which the temperature of the surface to be polished of the workpiece can be determined from the amount, and (b) a wavelength at which at least one infrared ray does not become a disturbance among the infrared rays radiated from a part emitting the disturbance. Or, it is taken out from the rear surface side of the central portion of the work so as to be the infrared ray B of the wavelength range or the wavelength range including the wavelength or the wavelength range. 2) Measure the radiation amounts Ea and Eb of the infrared rays A and B; ) The radiation amount Eb is converted to the radiation amount Ea ′ of the wavelength or wavelength range of the infrared ray A, or the radiation amount Ea is converted to the radiation amount Eb ′ of the wavelength or wavelength range of the infrared ray B; ) From the difference between the 'difference or Eb and Eb of' Ea and Ea, a polishing method of measuring temperature and determining the temperature in the polished surface of the workpiece.

In this method, the infrared rays A and B of a predetermined wavelength or a wavelength range are selected, and the radiation amount of one infrared ray is converted into the radiation amount of the other infrared ray, so that the background is removed with high accuracy and the polishing is performed. Find the temperature. Hereinafter, the wavelength or the wavelength range of the infrared ray A is λa, and the infrared ray B is
The first method will be described in detail with the wavelength or wavelength range as λb.

The infrared ray A is an infrared ray having a wavelength or a wavelength range from which the temperature of the surface to be polished of the workpiece can be determined from the radiation amount. That is, the infrared ray A is an infrared ray for which the temperature of the surface to be polished of the workpiece can be uniquely obtained from the radiation amount when there is no background. Infrared A
It can also be referred to as infrared light that gives information about the temperature of the surface to be polished of the work. The infrared rays A are generally emitted from the surface to be polished of the work. In the polishing temperature measuring method of the present invention, the infrared rays A are taken out on the back side of the work, and the radiation amount is measured on the back side of the work. Therefore, infrared A
Is preferably an infrared ray having a wavelength or a wavelength range that is radiated from the surface to be polished of the work and transmitted through the work, or an infrared ray having a wavelength range including the wavelength or the wavelength range. However, the infrared ray A is not limited to this, and has a certain correlation between the radiation amount and the temperature of the work surface to be polished. Any infrared ray that can uniquely determine the temperature may be used.

When the workpiece is a semiconductor wafer having a surface on which wiring such as Cu is formed, and the surface to be polished is formed by the semiconductor wafer and the wiring portion, infrared rays radiated from the surface of the wiring portion cause the infrared light to pass through the wiring portion. It cannot be transmitted. In that case, for such a work, a part of the surface to be polished (that is, the surface of the wiring portion)
May not be able to measure the infrared radiation emitted from the back of the work. However, since the wiring portion is extremely thin, the temperature can be considered to be substantially the same in the thickness direction.
If so, the surface of the wiring portion in contact with the wafer (ie,
An infrared ray having the same wavelength and radiation amount as the infrared rays emitted from the surface is also emitted from the bottom face). Since infrared rays emitted from the bottom surface of the wiring portion can pass through the semiconductor wafer, the temperature of the surface of the wiring portion can be approximately measured by measuring the amount of radiation. In such a case, the “infrared ray radiated from the surface to be polished” of the work includes the infrared ray radiated from the vicinity of the polished surface of the work (that is, the bottom surface of the wiring portion).

The infrared ray B is an infrared ray of a wavelength or a wavelength range that does not cause disturbance, or a wavelength range including the wavelength or the wavelength range, out of the infrared rays radiated from the part that emits the disturbance. “Disturbance” is infrared light that affects the measurement of the polishing temperature, and the amount of radiation corresponds to the background. Generally, the infrared light that becomes a disturbance is infrared light having the same wavelength or wavelength range as the infrared light A. The “portion that radiates disturbance” is a portion that emits infrared light having the same wavelength or wavelength range as the infrared light A and affects the polishing temperature measurement. The “portion that radiates disturbance” is generally a portion other than the surface to be polished of the work (for example, the back surface of the work and a member constituting the polishing apparatus). The term “infrared ray having a wavelength or a wavelength range that does not cause disturbance” refers to an infrared ray that does not affect the measurement of the polishing temperature, that is, an infrared ray that does not become a background. The “infrared ray having a wavelength or a wavelength range that does not cause a disturbance” may be an infrared ray that includes a wavelength or a wavelength range that causes a disturbance as long as the wavelength or the wavelength range does not cause a disturbance.

The infrared ray B is preferably an infrared ray having a wavelength or a wavelength range that does not substantially pass through the work, or an infrared ray having a wavelength range including the wavelength or the wavelength range.
The term “infrared ray of a wavelength or a wavelength range that cannot be substantially transmitted” includes infrared rays of a wavelength or a wavelength range having a transmittance of 0, and a wavelength or a wavelength range of a transmittance or a wavelength range of a very small (for example, several percent). Includes infrared.

If the infrared ray B is an infrared ray having a wavelength or a wavelength range that does not substantially transmit the work, the infrared ray B cannot be transmitted through the work even if it is emitted from the surface to be polished of the work. Has no effect. Therefore, if the amount of infrared radiation having a wavelength or a wavelength range that does not substantially transmit through the work is used, the influence of infrared radiation radiated from a portion other than the surface to be polished of the work (for example, a space through which infrared light passes) on the polishing temperature is considered. Can be more accurately eliminated, and the polishing temperature can be determined more accurately.
Infrared light having a wavelength or a wavelength range that does not substantially pass through the work is emitted from, for example, a member that defines an optical path of infrared light emitted from the surface to be polished of the work.

The infrared rays A and B are, for example, based on a wavelength λz, an infrared ray satisfying λa ≦ λz is referred to as an infrared ray A, and
An infrared ray with b> λz may be extracted as an infrared ray B. λa and λb are ones when λa includes a wavelength or a wavelength range that is radiated from the polished surface of the work and transmits through the work, and a wavelength or a wavelength range that does not substantially transmit the work is included in λb. Copies may be duplicated.

The wavelength or wavelength range of the infrared light that passes through or substantially does not pass through the work differs depending on the type of the work. For example, those work SiO ₂ film is formed on a surface of a semiconductor wafer made of Si, the case of polishing the SiO ₂ film surface, an infrared ray having a wavelength or wavelength range is within the range of 1.5~4μm It is preferable to select the infrared ray A (that is, the infrared ray that passes through the work) and the infrared ray having a wavelength or a wavelength range within the range of 4 to 6 μm as the infrared ray B (that is, the infrared ray that does not pass through the work).

In the first method, the radiation amount (ie, background) of the disturbance is obtained indirectly by measuring the radiation amount of the infrared light which does not cause disturbance. In general, if the relationship between the wavelength, the amount of infrared radiation, and the temperature is determined in advance for a certain temperature measurement target, the radiation amount Er of the infrared light R in the wavelength or wavelength range λr radiated from the temperature measurement target is radiated from the target. Λs (λr ≠ λs)
Can be converted to the radiation amount of the infrared ray S. Therefore, for the member that emits infrared light B, the relationship between the wavelength, the amount of infrared radiation, and the temperature is determined in advance, and by measuring the amount of radiation Eb of infrared light B, the infrared light of λa emitted from the portion other than the surface to be polished of the work is measured. The radiation amount Ea ′ can be obtained. E
Since a 'corresponds to the background, Ea and Ea'
Is equivalent to the amount of radiation that uniquely gives the temperature of the polished surface of the work. The radiation amount of the infrared ray A is (Ea-Ea ')
Is obtained from the relationship between the wavelength, the amount of infrared radiation, and the temperature previously obtained for the work. The obtained temperature corresponds to the polishing temperature.

Alternatively, it is also possible to convert the radiation amount Ea into a radiation amount Eb ′ of infrared light of λb radiated from the surface to be polished of the work, and obtain the polishing temperature from the difference between Eb and Eb ′. In this case, Eb corresponds to the background.

Since both Ea and Eb are measured when the work is being polished, the amount of infrared radiation radiated from each member of the polishing system whose temperature has been raised excluding the surface to be polished of the work is defined as the background. Can be measured. Therefore, according to the present invention, a more accurate polishing temperature can be obtained by performing temperature calibration that takes into account the rise in ambient temperature.

A second method of obtaining the polishing temperature from the amount of infrared radiation of two different wavelengths or wavelength ranges is as follows: 1) Extract infrared rays α and infrared β of two different wavelengths or wavelength ranges, and 2) perform polishing. In the system, the temperature Tα of the surface to be polished of the work and the temperature Tβ of one portion that emits disturbance are changed, and the radiation amount Eα of the infrared ray α at each temperature combination is changed.
And the amount of radiation Eb of infrared β was measured, and
The correlation fα between α, Tα and Tβ, and Eβ, T
The correlation fβ between α and Tβ is obtained in advance, and 3) the radiation amount Eα of the infrared ray α and the radiation amount Eβ of the infrared β are measured while polishing the object to be processed, and a combination of the two measured radiation amounts Eα and Eβ Is a method of measuring the polishing temperature by obtaining the temperature of the surface to be polished of the work based on the correlation fα and fβ.

In the second method, infrared rays α and β
Of the workpiece and the temperature T of the polished surface of the workpiece
As long as there is a correlation between α and the temperature Tβ of one part emitting the disturbance, that is, as long as Tα and Tβ change, Eα and Eβ change, the wavelength or wavelength range of infrared α and β is There is no particular limitation. This is because in this method, the polishing temperature is determined by directly applying the correlation determined in advance.

One part that emits a disturbance selected to determine the correlation is as described above in connection with infrared B and emits a disturbance during polishing that affects the measurement of the polishing temperature. A member or element. Such a member or element is, for example, an inner wall surface of a cylindrical shaft portion that constitutes a work holding mechanism described later. Temperature Tα of surface to be polished of work and temperature Tβ of one part radiating disturbance
Is varied using a suitable heater or cooling device. Tα and Tβ are measured with a suitable thermometer (eg, a thermocouple thermometer).

The infrared rays α and β may be emitted from any part as long as the above conditions are satisfied. Preferably, the infrared ray α is an infrared ray emitted from the surface to be polished of the work like the infrared ray A in the first method. More preferably, the infrared ray α is a wavelength or a wavelength range transmitting the work, or an infrared ray including the wavelength or the wavelength range. Preferably, the infrared ray β is an infrared ray emitted from one part that emits the disturbance. More preferably, like the infrared ray B in the first method, the infrared ray β is an infrared ray having a wavelength or a wavelength range that does not cause disturbance, or an infrared ray having a wavelength range including the wavelength or the wavelength range.

The correlation fα can be represented by a graph in which the X axis is Tα and the Y axis is Tβ. Specifically, T
The radiation amount of the infrared ray α when α is x1 and Tβ is y1 is obtained, and this is plotted by adding the radiation amount to the (x1, y1) coordinates. By changing the combination of (x, y), plot as many as possible (for example, 1000 or more). By connecting plots of the same value (for example, Ea1) among the plots in the graph, the relationship between Tα (x) and Tβ (y) when the radiation amount of the infrared ray α is Eα1 can be understood. Among the plots, the plots of the values of Eα2, Eα3. A relationship is determined for the k radiation dose values. The correlation fβ is also obtained in a similar manner by measuring the amount of radiation of the infrared β, and can be represented by a similar graph.

The radiation amount of infrared ray α measured during polishing is E
αk 'and the radiation amount of infrared β is Eβm',
A curve connecting plots of Eα = Eαk ′ and Eβ = Eβ
By superimposing the curves connecting the plots of m ', the temperature T of the polished surface of the work can be calculated from the x coordinate of the intersection of these curves.
α is required.

Alternatively, each curve in which Eα is Eα1 to Eαk is obtained as a function Eα _i = g _i (x, y) (i = 1 to k) where Tα and Tβ are variables x and y, and Eβ is A function Eβ _j = h _j (x, y) (j = 1) where Tα and Tβ are variables x and y, respectively, for each of the curves Eβ1 to Eβm
To m); select an appropriate function from the measured Eα and Eβ, or, if there is no function corresponding to the measured value, obtain an appropriate function from another function; Equation, and solving this gives T
α may be obtained.

For example, when the radiation amount of the infrared ray α measured during polishing is Eαk ′ and the radiation amount of the infrared ray β is Eβm ′, the temperature of the surface to be polished of the work is Eαk ′ = g _{k ′} ( x, y) Eβm '= h m' (x, obtained by solving the simultaneous equations represented by y). Among the obtained solutions, x corresponds to Tα.

The second method for obtaining the correlation in advance is as follows:
When the infrared ray α is an infrared ray having a wavelength or a wavelength range that transmits the work, and the infrared ray β is an infrared ray that has a wavelength or a wavelength range that does not transmit the work, a member (for example, a polishing pad) located on the surface to be polished of the work piece Infrared α and β
Is preferably employed when emitting light. Since the infrared ray β radiated from the member located on the polished surface side of the work cannot pass through the work, the radiation amount is not measured on the back surface side of the work. Therefore, when the polishing temperature is measured by the above-described first method, the measured radiation amount Eβ of the infrared ray β (corresponding to the infrared ray B in the first method) (corresponding to the radiation amount Eb in the first method) is as follows. The radiation amount may be smaller than the actual radiation amount, and the background may not be obtained accurately. On the other hand, in the second method, the radiation amount Eβ of the infrared ray β actually measured and the temperature T of the polished surface of the work are measured.
Since the correlation between α and the temperature Tβ of one part of the radiating disturbance is determined, it does not matter that the measured Eβ is smaller than the actual radiation dose.

In the second method, the correlation is determined under conditions closer to the actual polishing conditions, and the polishing temperature is determined based on the correlation, whereby the polishing temperature can be measured with higher accuracy. Therefore, for example, when infrared rays α and β are emitted from the polishing pad, the correlation is such that the temperature of the surface to be polished of the work (that is, the polishing surface of the polishing pad) is kept in a state where the work and the polishing pad are in contact with each other. It is preferable to change the value. This is because the radiation amount Eα including the radiation amount of the infrared ray α emitted from the polishing pad is measured, and the correlation is obtained in advance based on the measured radiation amount Eα.

The temperature of the surface to be polished of the work may be obtained by measuring the amount of infrared radiation of three or more different wavelengths or wavelength ranges.

In the first method, for example, when measuring the radiation amount of infrared rays of three different wavelengths or wavelength ranges, in addition to the infrared rays A and B, infrared rays radiated from a part that radiates disturbance are used. Then, infrared rays C of another wavelength or wavelength range that does not cause disturbance may be extracted.
The radiation amount Ec of the infrared ray C is converted into the radiation amount Ea ″ of the wavelength of the infrared ray A or the wavelength range. The temperature of the polished surface of the work is obtained from the difference between the above Ea and Ea ′.
The temperature of the polished surface of the workpiece can be, for example, an average value of the two temperatures obtained. Alternatively, Ea is determined by the wavelength of infrared rays B and C or the wavelength range of infrared rays. Converted into the radiation amounts Eb 'and Ec'
The polishing temperature may be determined from the difference between b ′ and Eb and the difference between Ec ′ and Ec. The polishing temperature can be determined in the same manner when measuring the amount of infrared radiation of four or more different wavelengths or wavelength ranges.

Alternatively, in addition to the infrared ray A and the infrared ray B, an infrared ray D of another wavelength or a wavelength range from which the temperature of the surface to be polished can be obtained from the radiation amount is taken out, and the radiation amount Ed is measured. Is also good. In that case, Eb
Is converted to the radiation amount Ed 'of the wavelength of the infrared ray D or the wavelength range, and the polishing temperature is determined by the difference between Ea and Ea' and the difference between Ed and Ed '.
Is determined from the difference between Alternatively, the polishing temperature can also be obtained by converting Ea and Ed into the wavelength of infrared B or the amount of radiation in the wavelength range.

In the polishing temperature measuring method for obtaining the correlation in advance, in addition to the infrared rays α and β, an infrared ray γ of another wavelength or a wavelength range is taken out, the respective values of the radiation amounts Eγ1 to Eγj, and the polished surface of the workpiece to be polished. The relationship between the temperature Tα and the temperature Tβ of one portion that emits disturbance is obtained in advance as a correlation fγ. The polishing temperature can be obtained based on the correlation fα and the correlation fβ, and the correlation fα and the correlation fγ. The temperature of the polished surface of the work is
The average value of the two obtained temperatures may be used. The polishing temperature can be determined in the same manner when measuring the amount of infrared radiation of four or more different wavelengths or wavelength ranges.

In either case, the temperature of the surface to be polished of the work may be obtained by using a suitable arithmetic processing unit. The arithmetic processing device is, for example, a computer.

In the polishing temperature measuring method of the present invention, the infrared rays of at least two different wavelengths or wavelength ranges are preferably taken out on the back side of the center of the work (generally above the center of the work). By taking out infrared rays of at least two different wavelengths or wavelength ranges in this way, it is possible to measure the polishing temperature at the same position (the center in the present invention) of the workpiece during polishing without continuous interruption. It is. In particular, when polishing is performed by rotating a workpiece, a device for extracting infrared rays of at least two different wavelengths or wavelength ranges (for example, an optical filter to be described later) is rotated or connected to a rotary contact terminal. Without this, the infrared light can be continuously taken out, so that the structure of the entire polishing apparatus does not become complicated.

The amount of emitted infrared radiation of each wavelength or wavelength range taken out is measured by an infrared radiation measuring device on the back surface side of the work. In the case of measuring the amount of infrared radiation in this way, even if polishing is performed using a polishing liquid (slurry), the infrared passage is not contaminated with the slurry, and therefore, temperature measurement is performed between the pad and the work. Hardly affected by slurry interposed in When measuring the amount of infrared radiation on the back side of the center part of the work, the infrared radiation amount can be measured continuously without rotating the infrared radiation measuring instrument or connecting it to the rotating terminal, The structure of the entire polishing apparatus is not complicated.

The infrared radiation measuring device is specifically a pyroelectric infrared radiation sensor or an infrared radiation thermometer. In general, infrared radiometers have a constant (measurement distance):
It is designed to be measured at the ratio of (measurement area diameter), and the longer the measurement distance, the larger the diameter of the measurement area.

According to the polishing temperature measuring method of the present invention, the temperature of the work at the contact surface between the work and the polishing pad when the work is actually being polished can be measured with high accuracy.
Therefore, if the correlation between the polishing amount of the workpiece and the polishing temperature is known, the polishing rate can be controlled by applying the correlation.

In the polishing temperature measuring method of the present invention, the polishing temperature is measured in a non-contact manner. Therefore, while the polishing temperature is measured by the method of the present invention while the work is being polished, a thermocouple is used. The temperature measuring means does not locally affect the processing pressure. Therefore, according to the polishing temperature measuring method of the present invention, the correlation between the polishing amount of the workpiece and the polishing temperature can be obtained in a state where the temperature measuring means does not affect the processing pressure. The obtained correlation can also be applied when the polishing conditions are slightly different (for example, when the processing pressure is locally different due to the undulation form of the work, the undulation of the pad, etc.).

As described above, the correlation between the polishing amount of the work and the polishing temperature obtained by the polishing temperature measuring method of the present invention can be applied to a wide range. Therefore, it is not always required to obtain the correlation for each processing lot, and the correlation may not be required depending on the processing lot. Therefore, if the polishing temperature measuring method of the present invention is used, the time required for the operation of determining the correlation can be reduced as a whole.

Next, a preferred embodiment for extracting infrared rays of at least two different wavelengths or wavelength ranges will be described.

In the first preferred embodiment, at least two infrared rays having different wavelengths or wavelength ranges are extracted by using optical filters having at least two different transmission wavelength bands. Infrared rays detected on the back side of the central portion of the work generally include infrared rays of various wavelengths. The optical filter transmits infrared rays of a predetermined wavelength or wavelength range among infrared rays including various wavelengths. Therefore, if two or more filters are used, two or more infrared rays having different wavelengths or wavelength ranges can be extracted.

During polishing, at least two optical filters are sequentially arranged on the optical path of the infrared ray detected on the back surface side of the central portion of the work, so that infrared rays of different wavelengths or wavelength ranges are sequentially extracted. As will be described later, each optical filter is sequentially arranged on the optical path of the infrared ray by rotating or rotating a plurality of filters using, for example, a switch. It is preferable that at least two optical filters are sequentially arranged on the optical path of infrared light so that infrared light transmitted through each optical filter can be measured for 1 to 2 seconds.

The infrared light extracted by the optical filter is
Preferably, the measurement is performed using one infrared radiometer that can measure the infrared radiation of each wavelength or wavelength range. For example, in the first method, when the infrared ray A having the wavelength λa and the infrared ray having the wavelength λb (λa <λb) are respectively extracted by an optical filter, the infrared radiation amount measuring device determines that the wavelength λ is λa ′ ≦ λ ≦ λb ′ ( Where λa ′ ≦ λ
a, λb ≦ λb ′) It is preferable to be able to measure the amount of infrared radiation within the range. Alternatively, the infrared radiometer may be capable of separately measuring infrared radiation at wavelengths λa and λb. With such an infrared radiation meter, the wavelength λa transmitted through the optical filter
Can be measured with a single infrared radiation meter. If the infrared radiation amount of a plurality of different wavelengths or wavelength ranges can be measured by one infrared radiation amount measuring device, it becomes possible to make the polishing apparatus compact and reduce the cost required for measuring the polishing temperature.

The optical filter is a filter that cuts and transmits infrared light having a wavelength longer than a predetermined wavelength, a filter that cuts and transmits infrared light having a wavelength shorter than a predetermined wavelength, and a filter that transmits only infrared light having a predetermined wavelength. Bandpass optical filter). In order to extract infrared light having a predetermined wavelength or a predetermined wavelength range, two or more optical filters may be used in combination.

In a second preferred embodiment, the infrared light path is split into at least two different wavelengths or wavelength ranges of infrared light by using a wavelength-selective reflector to thereby provide at least two different wavelengths or wavelengths. Simultaneously extract infrared light in the area. Unlike the first embodiment, the infrared light of each wavelength or wavelength range travels in a different optical path. Therefore, in this embodiment, at least two infrared radiometers are required so that the infrared radiation at at least two different wavelengths or wavelength ranges can be measured.

In this embodiment, the amount of infrared radiation of each wavelength or wavelength range is measured simultaneously, and the polishing temperature is obtained from two or more infrared radiations measured simultaneously. Therefore, according to the second aspect, the polishing temperature can be measured with higher accuracy.

The wavelength-selective reflector has, for example, a wavelength λw
This is a reflecting plate that transmits infrared rays on the longer wavelength side and reflects infrared rays on the shorter wavelength side than the wavelength λw. The infrared radiometer is disposed on the optical path of infrared light transmitted through the reflector and on the optical path of infrared light reflected by the reflector.

The wavelength-selective reflector may be one that branches an infrared light path of various wavelengths into infrared light paths of three or more different wavelengths or wavelength ranges. In that case, the amount of infrared radiation may only be measured for infrared radiation at two different wavelengths or wavelength ranges, and the remaining infrared radiation need not be measured.

Next, the present invention according to the second aspect will be described. The polishing method of the present invention provided in the second aspect is a polishing method implemented using the polishing temperature measuring method provided in the first aspect.

If the polishing temperature is measured by the above-described measuring method, the temperature of the work at the contact surface between the work and the polishing pad when the work is actually being polished can be measured. Therefore, if the correlation between the polishing amount of the workpiece and the polishing temperature is known, the polishing rate can be controlled by applying the correlation.

In the polishing method of the present invention, it is preferable to polish the work while controlling the polishing temperature by changing the process parameters so that the polishing temperature becomes a predetermined temperature. The optimum polishing temperature is determined according to the type of the work, the polishing pad, the polishing liquid, and the like. By controlling the polishing temperature, the polishing rate of the work can be made constant, so that the work can be uniformly polished.

The process parameters to be changed are selected from the processing pressure, the polishing rate, the temperature of the member close to the work, the temperature of the fluid used to press the work against the polishing pad, the temperature of the surface plate, and the temperature of the polishing liquid. Is done. The process parameter to be changed may be one or more.
The polishing speed corresponds to a relative speed of the work to the polishing pad, and may be simply referred to as “relative speed” in this specification.

The polishing temperature is mainly determined by the frictional heat generated between the work and the polishing pad, and the amount of the frictional heat changes according to the manner of sliding of the polishing pad with respect to the work. Therefore, if the processing pressure and the polishing rate that determine the mode of sliding are changed, the polishing temperature will also change.

The polishing temperature can also be controlled by changing a process parameter selected from the temperature of a member close to the work, the temperature of a fluid used to press the work against the polishing pad, and the temperature of the platen. The member close to the work is a member that constitutes the work holding mechanism or a member attached to the work holding mechanism,
A member sufficiently close to the work so that the work can be heated or cooled. Such a member is, for example, a heater arranged near the work of the work holding head. Or,
When the work is pressed against the polishing pad by the pressure of the fluid, the temperature of the work and, consequently, the polishing temperature can be changed by heating or cooling the fluid. Alternatively, the temperature of the polishing pad, and thus the polishing temperature, can be changed by heating or cooling the surface plate on which the polishing pad is arranged.

The temperature of the polishing liquid supplied between the work and the polishing pad also affects the polishing temperature.

When polishing the work, it is preferable to accurately detect the polishing end point of the work. Incorrect detection of the polishing end point of the work leads to insufficient polishing or excessive polishing, which deteriorates the quality of the polished work.

In the polishing method of the present invention, it is preferable that the polishing end point is detected based on a change amount of the polishing temperature (a difference between two values when the polishing temperature changes from one value to another value). This is a method of detecting a polishing end point using a phenomenon in which a coefficient of friction changes when a material to be polished changes, whereby the polishing temperature rises or falls sharply. Specifically, when a metal film is formed on the surface of a semiconductor wafer having a groove formed thereon, and the metal other than the groove is removed by the CMP method, when the entire surface to be polished is partially changed from metal to semiconductor. It is possible to determine the polishing end point based on the amount of change in the polishing temperature. Alternatively, a metal wiring is formed on a semiconductor wafer, an insulating film is further formed thereon, and the insulating film is
When the metal wiring is exposed on the surface by polishing by MP method,
It is also possible to determine the polishing end point by using a change in the polishing temperature when a part of the surface to be polished changes from an insulating material to a metal.

When the polishing temperature is controlled by changing the process parameter, the polishing end point is determined based on the change amount of the process parameter (the difference between the two values when the process parameter changes from one value to another value). Can be detected. This is because when the polishing temperature is rapidly increased or decreased, the amount of change in the process parameter is correspondingly increased.

When the polishing temperature is controlled in a closed loop, the polishing end point can be detected based on a signal transmitted to a control element that changes a process parameter.
In a closed loop, a signal that changes a process parameter is sent to a control element based on the measured polishing temperature. If this signal is a signal that instructs to greatly change the process parameters, it means that the polishing temperature has changed rapidly. Therefore, by continuously monitoring this signal, it is possible to detect the polishing end point before greatly changing the process parameters.

The polishing method of the present invention may include a step of cooling the polishing surface of the polishing pad before starting the polishing of the work and / or after finishing the polishing of the work. The term “before starting the polishing of the work and / or after the end of the polishing of the work” means, for example, when the work is loaded and unloaded. Since the polishing surface of the polishing pad after polishing is generally in a state where the temperature has risen, if the next work is polished as it is, a desired polishing rate may not be obtained depending on the type of the work and the like. Therefore, if necessary, after polishing the work, cool the polishing surface of the polishing pad before polishing the next work,
Temperature suitable for polishing the next workpiece (for example, normal temperature)
And Cooling may also be performed to keep the polishing temperature at the start of polishing always at a predetermined temperature. Cooling is performed in any manner. For example, the surface of the polishing pad may be cooled by blowing a gas or liquid at a predetermined temperature. The surface of the polishing pad may be heated, if necessary, before starting polishing of the work and / or after finishing polishing of the work.

Next, the present invention according to the third aspect will be described.
The work holding mechanism of the present invention provided in the third aspect is a work holding mechanism that presses a work against a polishing pad and holds the work in a plane perpendicular to the pressing direction. A plate member having an infrared transmitting portion,
And a lip seal attached to the plate member so as to be located on the back surface of the peripheral portion of the work, and when the work is held, a space is formed by the plate member, the lip seal and the work, and supplied to the space. The workpiece is pressed against the polishing pad by the pressure of the fluid. This work holding mechanism is particularly suitable for carrying out the polishing temperature measuring method and the polishing method of the present invention.

With respect to the work holding mechanism of the present invention, the “surface” of the member constituting the work holding mechanism is defined as the polishing surface of the two surfaces parallel to the polishing surface of the polishing pad when incorporated in the work holding mechanism. The surface located closer to the pad. On the other hand, the “back surface” or “back surface” of the member that constitutes the work holding mechanism refers to the side farther from the polishing pad among the two surfaces parallel to the polishing surface of the polishing pad when incorporated in the work holding mechanism. Refers to the surface located.

Inside the work holding mechanism, a passage through which infrared light can pass is formed by a cylindrical shaft portion and a plate member having an infrared transmitting portion. The presence of this passage makes it possible to extract infrared rays of at least two different wavelengths or wavelength ranges on the back surface side of the central portion of the work. An optical filter or a reflector, for example, is provided inside or above the cylindrical shaft to extract infrared rays of at least two different wavelengths or wavelength ranges.

The cylindrical shaft portion is a shaft portion having a hollow portion. The shaft is provided such that its hollow portion overlaps the center of the work. The axis passing through the center of the cross section of the shank preferably passes through the center of the workpiece. The shaft may be a rotating shaft as required.

The infrared transmitting portion is formed of a material through which infrared light can pass. The material through which the infrared light can be transmitted depends on the wavelength of the infrared light, and examples of the material that transmits the infrared light having a wavelength of 1.5 to 6 μm include fluorite, BaF _2, and S
i. The infrared transmitting portion is preferably arranged such that its center overlaps with the center of the work.

The shape and size (length and cross-sectional shape) of the shaft portion and the shape and size of the infrared transmitting portion are determined by the ratio of (measurement distance) to (diameter of measurement area) of an infrared radiation measuring instrument (for example, infrared radiation thermometer). Is determined according to. In the present invention, the ratio of (measurement distance) :( diameter of measurement area) is 300:
An infrared radiation meter of about 1 to 500: 1 is preferably used. The distance between the infrared radiation meter and the polishing surface of the polishing pad is preferably 500 to 1000 mm, and the measurement area preferably has an area corresponding to the area of a circle having a diameter of 20 to 40 mm. The shapes and dimensions of the shaft portion and the infrared transmitting portion are appropriately selected in consideration of the dimensions of other members based on these preferable numerical ranges.

The plate member forms a space (or pressure chamber) for accommodating a fluid for pressing the work against the polishing pad, and has an infrared transmitting portion for transmitting infrared emitted from the surface to be polished of the work. It is a member to be made. Here, the fluid means a gas or a liquid. The gas is, for example, air, and the liquid is, for example, water. The shape and dimensions of the plate member are not limited as long as it acts in this manner.

The plate member is preferably a lightweight material having high rigidity and formed of a material that does not become a source of chemical contamination or organic contamination for a work (eg, a semiconductor wafer). Here, “chemical contamination” means that heavy metal ions such as Cu, Fe, and Cr adhere to the work, and “organic contamination” means that organic substances adhere to the work. The plate member is preferably made of a ceramic such as alumina or stainless steel.

It is preferable that the outer edge of the plate member overlaps the outer edge of the work. Therefore, when the work is in the form of a disc, the plate member is preferably in the form of a disc having the same diameter as the diameter of the work. The plate member may be formed from two or more parts. The plate member is not necessarily required to be a flat plate, and a plate member having a thickness partially different and having irregularities is also included.

The "peripheral portion of the work" refers to a portion including the outer edge of the work, and a portion where the lip seal is located (that is, contacts) when the work holding mechanism of the present invention holds the work. The outer edge of the work is the outermost part that defines the contour of the work, but a portion having an extremely narrow width including the outer edge of the work, as in the case where "the edge of the work is prevented from being rounded off" as described later. Sometimes it refers to. As in the case where the work is a disk and the lip seal is a ring-shaped object having a width of about 1/40 or less of the diameter of the work (that is, a distance between the outer circumference and the inner circumference), If the width of the seal is very narrow, the periphery of the work may be equal to the outer edge of the work. For example, when the work is a disk having a diameter of 200 mm and an annular lip seal with a width of about 5 mm or less is located on the back surface of the periphery of the work, the periphery of the work may be said to be equal to the outer edge of the work. is there.

The lip seal forms an air-tight or liquid-tight seal when the work holding mechanism holds the work.
Prevents fluid from leaking from the space formed by the plate member, the lip seal and the work. The lip seal is, for example, an O-ring made of an elastic material. The lip seal is preferably an annular body having a width of about 1/40 of the diameter of the work when the work is a disk (about 5 mm when the work is a disk having a diameter of 200 mm).

In the work holding mechanism of the present invention, it is preferable that all the members constituting the work holding mechanism are all formed of the same material or a material having the same or similar emissivity. When the polishing temperature is measured by the above-described method for obtaining the background, if infrared rays B are emitted from a large number of members having different emissivities, error factors may increase and the background may not be obtained correctly. This is because it is preferable to eliminate such a possibility as much as possible.

If this work holding mechanism is used, the infrared light that has passed through the infrared transmitting portion and the shaft portion of the work holding mechanism is used for measuring the polishing temperature. Therefore, if the polishing temperature is measured using this work holding mechanism, the polishing temperature in the vicinity of the center of the work can always be measured.Optical filters or reflectors without using rotating terminals, etc. The number of members located between the infrared radiation measuring instrument and the work can be arranged and the polishing temperature can be measured without complicating the structure of the polishing apparatus. The average temperature of a circle with a small diameter of about 20 to 40 mm, which has small absorption of infrared rays, can be measured. Compared with the case of measuring the local temperature, the influence of local temperature variation on the measured temperature is smaller. The advantage of being small is provided.

When the work is held by the work holding mechanism, a closed space formed by the plate member, the lip seal and the work is formed. A fluid can be supplied to the space, and the work is pressed against the polishing pad by the pressure of the fluid supplied to the space. On the other hand, if the space is evacuated, the work can be attracted to the lip seal, which is convenient for conveying the work before and after polishing the work. Since the plate member having the infrared transmitting portion defines the space for containing the fluid, by using this work holding mechanism, it is possible to simultaneously perform the pressing of the work by the fluid and the polishing temperature measurement by measuring the infrared radiation amount.
The polishing temperature is measured more accurately.

The work holding mechanism of the present invention further includes a diaphragm for holding the peripheral portion of the plate member so as to be movable in the pressing direction, and a balloon-like elastic member capable of contacting the back surface of the peripheral portion of the plate member. It is preferable that the peripheral portion of the work can be pressed against the polishing pad via the plate member and the lip seal by expanding the balloon-like elastic body by the pressure of the fluid supplied to the polishing pad.

The "peripheral portion of the plate member" means a portion including the outer edge of the plate member. The peripheral portion of the plate member is an annular portion including the outer edge of the plate member when the plate member has a disk shape. When the plate member has a disk shape and the diameter of the plate member is the same as the diameter of the work, the peripheral portion of the plate member held by the diaphragm has a width corresponding to １ ／ to ８ of the diameter of the work ( (A distance between the outer periphery and the inner periphery of the annular portion). This annulus is preferably concentric with the workpiece. Therefore, for example, when both the plate member and the work are discs having a diameter of 200 mm, the peripheral edge of the plate member has a width of 50 to 25 mm including the outer edge of the plate member.
Is an annular portion.

The “balloon-like elastic body” is at least partially made of an elastic material, has a closed space through which a fluid can flow in and out, and at least partially according to the pressure of the fluid flowing into the space. Can elastically deform (eg, expand and contract). Here, the fluid means a gas or a liquid. The gas is, for example, air, and the liquid is, for example, water.

The balloon-like elastic body includes one having a balloon-like shape formed of a thin member (for example, a sheet) made of an elastic material. In addition, the balloon-like elastic body includes one in which a thin member (for example, a sheet) made of an elastic material is formed by forming a space together with other members constituting the work holding mechanism. Only the thin member made of is elastically deformed.
The thin member constituting the balloon-like elastic body is, specifically,
It is preferably a sheet made of neoprene rubber or silicone rubber and having a thickness of 0.1 to 0.5 mm.

The balloon-like elastic body preferably has a structure such that the fluid flowing into the space does not substantially leak outside. Therefore, for example, when the balloon-like elastic body is composed of a sheet made of an elastic material and another member constituting the work holding mechanism, it is preferable to attach the sheet made of the elastic material to the work holding mechanism in an airtight or liquid tight manner.

The diaphragm constituting the work holding mechanism is a thin plate-like member which can be elastically deformed by a pressing force generated by expansion of the balloon-like elastic body. The diaphragm is preferably made of a material which has sufficient strength and corrosion resistance so as not to be damaged by repeated elastic deformation and does not become a source of chemical contamination and organic contamination to a work (eg, a semiconductor wafer). Specifically, the diaphragm is made of Hastelloy or stainless steel and has a thickness of 0.05 to
It is preferably a 0.2 mm thick plate or a 0.1 to 0.5 mm thick plate (or sheet) made of neoprene rubber.

The diaphragm holds the periphery of the plate member movably in the pressing direction. Specifically, a part of the diaphragm is attached to the plate member, and the other part is attached to a member other than the plate member of the work holding mechanism. As a result, a portion between the portion attached to the plate member and the portion attached to the other members is in a free state, and this free portion can be freely elastically deformed as a flexure (for example, flexure). Mu). As a result, the periphery of the plate member is displaced with respect to the other members.

The attachment of the diaphragm to the plate member can be carried out, for example, by dividing the peripheral edge of the plate member into two members, sandwiching the diaphragm between the two members, and fixing with a bolt or an adhesive.
Attachment of the diaphragm to members other than the plate member can be similarly performed. As members other than plate members,
For example, there is a holding base. The “holding base” is a basic structural member that constitutes the entire work holding head having a work holding mechanism, and is a member that incorporates a plate member and the like. The holding base can be said to be the main body of the work holding head.
For members other than the plate member for attaching the diaphragm,
The retaining ring described later may be used.

In the above-described work holding mechanism, the diaphragm is an annular thin plate-shaped member when the peripheral portion of the plate member is annular.

In the case where the diaphragm is annular, if the inner peripheral portion is attached to the peripheral edge of the plate member, the outer peripheral portion is attached to a member other than the plate member. If the outer peripheral portion of the diaphragm is attached to the peripheral edge of the plate member, the inner peripheral portion is attached to a member other than the plate member. In any case, the portion between the outer peripheral portion and the inner peripheral portion is
It will elastically deform (for example, bend) as a bending portion. Here, the “outer peripheral portion” and the “inner peripheral portion” respectively refer to a portion including an outer edge and a portion including an inner edge of a member having an opening at the center (for example, a ring-shaped member).

The balloon-like elastic body is provided so as to be in contact with the back surface of the peripheral portion of the plate member. That is, the balloon-like elastic body is arranged so as to be able to displace (or move) the peripheral portion of the plate member when inflated, and to be in contact with the back surface of the peripheral portion of the plate member when inflated. Therefore, the “balloon-like elastic body that can be in contact with the back surface of the peripheral portion of the plate member” naturally includes a balloon-like elastic body that is in contact with the back surface of the peripheral portion of the plate member when not inflated. The balloon-like elastic body may be arranged so as to be in contact with the back surface of the peripheral portion of the plate member, and may be fixed to the back surface of the peripheral portion of the plate member with an adhesive or the like as necessary. Alternatively, as long as the plate member presses the workpiece against the polishing pad when the balloon-like elastic body expands, the balloon-like elastic body may be arranged so as not to contact the peripheral edge of the plate member when not expanding.

In the work holding mechanism in which the diaphragm and the balloon-like elastic body are arranged as described above, the direction in which the balloon-like elastic body that can come into contact with the back surface of the periphery of the plate member expands and presses the periphery of the plate member against the pad. When a force is applied to the peripheral edge of the plate member, the peripheral edge of the plate member is displaced (or moved) in a direction toward the polishing pad, and the flexible portion of the diaphragm is elastically deformed. When the pressure of the fluid decreases and contracts after the balloon-shaped elastic body expands, the flexible portion of the diaphragm is elastically deformed so as to return to the original state, so that the peripheral edge of the plate member moves in a direction away from the polishing pad. I do. Therefore, in the work holding mechanism having the diaphragm and the balloon-like elastic body, the displacement of the peripheral portion of the plate member in the pressing direction is controlled within a range in which the flexible portion of the diaphragm is elastically deformed, and in that sense, the diaphragm is the plate member. Is movably held in the pressing direction and the direction opposite thereto. The maximum displacement of the peripheral portion of the plate member is determined according to the material and thickness of the diaphragm, the length of the flexible portion, and the like. When the amount of displacement of the peripheral portion of the plate member is set in advance, the material and thickness of the diaphragm and the length of the bending portion, etc.
It is necessary to make a selection in order to realize the displacement.

The periphery of the plate member is flexibly held by the diaphragm. Specifically, for example, even if the work surface and the polishing surface of the polishing pad are not parallel and an inclination occurs between the two surfaces, if the flexure of the diaphragm is sufficiently long, one The two surfaces are made parallel by elastically deforming the portion differently from the other portions to correct the tilt.

When this work holding mechanism is used, a fluid is supplied to the space of the balloon-like elastic body and the balloon-like elastic body expands, so that the peripheral edge of the plate member is pressed, and the peripheral edge of the work is placed on the plate member. Is pushed by the peripheral edge. That is, the periphery of the work is pressed against the polishing pad via the periphery of the plate member and the lip seal. The peripheral portion of the work pressed by the peripheral portion of the plate member is only the surface of the portion in contact with the lip seal on the back surface of the work, and the area thereof is determined according to the width of the lip seal in contact with the back surface of the work. Is done.

According to this work holding mechanism, the peripheral portion of the work and the other portion (that is, the center portion of the work) can be independently pressed against the polishing pad using the balloon-like elastic body and the diaphragm. Therefore, the central portion of the work is independently pressed by the pressure of the fluid supplied to the space formed in contact with the back surface, and the peripheral portion is independently pressed by the pressure of the fluid supplied to the balloon-like elastic body. , The processing pressures of the central part and the peripheral part may be different from each other.

It is more preferable that the work holding mechanism of the present invention further includes a retainer ring surrounding the outer edge (or side surface) of the work. The retainer ring is provided to prevent the work from coming off the work holding head during polishing.

When the work holding mechanism of the present invention is provided with a retainer ring, the retainer ring is preferably held by a diaphragm having an axisymmetric structure whose axis is a symmetric axis passing through the center of the holding mechanism. Such a diaphragm is
Specifically, it is an annular plate-like object whose center is on the axis of symmetry and whose radial direction is perpendicular to the axis of symmetry, and the portion between the outer peripheral portion and the inner peripheral portion is elastically deformed as a flexible portion. (For example,
(Bend).

If the retainer ring is held by the annular diaphragm, even if the retainer ring moves in the pressing direction and stress is generated in the diaphragm, the diaphragm has a symmetrical structure, so that the diaphragm exerts a force acting in the radial direction. It is elastically deformed so as to be balanced around the axis of symmetry. That is, even if the retainer ring moves in the pressing direction, the center of the diaphragm does not largely shift, and the center of the retainer ring held by the diaphragm does not largely shift.
Therefore, if the retainer ring is held by the elastically deformable diaphragm in this manner, the horizontal displacement of the retainer ring can be effectively prevented. On the other hand, since the diaphragm is easily elastically deformed (for example, bent) in the pressing direction, the retainer ring can be moved in the pressing direction even with a small force.

The diaphragm for holding the retainer ring so as to be movable in the pressing direction is similar to the diaphragm for holding the peripheral portion of the plate member so as to be movable in the pressing direction, and is a member (for example, a holding base) other than the retainer ring and the retainer ring. It is attached.

[0113] Preferably, the retainer ring is also pressed against the polishing pad in a manner similar to the plate member. Specifically, the above-mentioned diaphragm for holding the retainer ring movably in the pressing direction and a balloon-like elastic body which can be in contact with the back surface of the retainer ring are provided, and the balloon-like elastic body is provided by the pressure of the fluid supplied into the balloon-like elastic body. It is preferable that the retainer ring is pressed against the polishing pad by the expansion of.

The balloon-like elastic body that can come into contact with the back surface of the retainer ring is the same as the above-described balloon-like elastic body that can come into contact with the back surface of the peripheral portion of the plate member. Therefore, the detailed description is omitted here. However, in the balloon-like elastic body which can be in contact with the back surface of the retainer ring, the shape of the portion in contact with the back surface of the retainer ring differs depending on the shape of the retainer ring with which it comes into contact. For example, when the retainer ring is annular, the shape of the portion of the balloon-like elastic body that contacts the back surface of the retainer ring also becomes annular.

By pressing the retainer ring against the polishing pad, the work is less likely to come off the holding head during polishing, so that the work jumps out and the work is thereby damaged. In addition, the polishing pad is pressed in the vicinity of the outer edge of the work to change the compression deformation state of the polishing pad, thereby preventing the outer edge of the work from being rounded. That is, by pressing the retainer ring, it is possible to control the balance of the processing pressure of the central portion, the peripheral portion, and the outer edge of the work with high accuracy.

Next, the present invention according to the fourth aspect will be described.
The polishing apparatus of the present invention provided in the fourth aspect is an apparatus for polishing a surface to be polished of a work with a polishing pad, and emits at least two different wavelengths or infrared rays of different wavelength ranges on the back surface side of the central portion of the work. It is a polishing apparatus provided with a unit for measuring the radiation amount of each extracted wavelength or wavelength range.

In the first aspect, the polishing apparatus of the present invention comprises: (a) a work holding mechanism of the present invention; (b) an optical filter having at least two different transmission wavelength bands and a switch of an optical filter; (D) a surface plate supporting the polishing pad; and (e) means for moving the work relative to the polishing pad. Become.

In the first embodiment, at least two optical filters having different transmission wavelength bands are provided to extract infrared rays having at least two different wavelengths or wavelength ranges. The optical filter is generally provided above the shaft of the work holding mechanism.

The polishing apparatus according to the first embodiment includes a switch for sequentially disposing each filter on the optical path of the infrared light that has passed through the work holding mechanism during polishing. The switcher, when disposing one filter on the optical path of infrared light, sequentially arranges each filter such that the center of the filter is on an axis perpendicular to the surface of the work passing through the center of the work. Is preferred.

For example, as shown in FIG. 5A, the switching device (39) is a turntable, and by rotating two optical filters (38a, 38b), one of the optical filters is changed to an infrared light. Optical path (indicated by broken lines in the figure)
It may be arranged above. Alternatively, as shown in FIG. 5B, the switch (39) may slide two optical filters (38a, 38b).

In the first embodiment, the infrared radiation meter is preferably provided on the back side of the center of the work (generally,
(Above the center of the work). When the work is in the form of a disk, the infrared radiation meter is preferably located in a circle concentric with the center of the work and having a diameter of 20 to 40 mm. More preferably,
The infrared radiometer is arranged on an axis perpendicular to the surface of the work passing through the center of the work.

In the second aspect, the polishing apparatus of the present invention comprises: (a) the work holding mechanism according to the third aspect; (b) a wavelength-selective reflector disposed on the back side of the center of the work; (C) an infrared radiation amount measuring device arranged on the optical path of at least two infrared rays among the infrared rays branched by the reflection plate; (d) a platen supporting the polishing pad; and (e) a work on the polishing pad. This is a polishing apparatus having means for relatively moving the polishing apparatus.

In the second embodiment, a wavelength-selective reflector is provided to extract infrared rays of at least two different wavelengths or wavelength ranges. The wavelength-selective reflector is disposed on the back side of the center of the work so as to pass and / or reflect the infrared light that has passed through the shaft of the work holding mechanism. The reflector is preferably arranged on an axis perpendicular to the surface of the work passing through the center of the work.

The infrared radiation amount measuring device is arranged on the optical path of at least two infrared rays among the infrared rays branched by the reflector. Therefore, the position of the infrared radiometer is determined according to the optical path of the infrared light. Alternatively, the type, position, angle, and the like of the reflector may be appropriately selected so that the direction of the optical path is as desired, and the infrared radiation meter may be arranged at a predetermined appropriate position.

The present invention is particularly preferably applied to polishing by the CMP method. The present invention also provides a polishing method other than the CMP method, for example, mechanical polishing (MP; Mechanical P).
olishing) and mechanochemical polishing (MCP;
Mechano Chemical Polishing) method.

[0126]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a polishing temperature measuring method and a polishing method according to the present invention will be described with reference to the drawings. Figure 1
FIG. 4 shows an embodiment of the polishing temperature measuring method and the polishing method of the present invention using the work holding mechanism of the present invention, respectively. In each drawing, the work is a semiconductor wafer (S
i). Although not shown, in this embodiment, the workpiece is polished by the CMP method, and a polishing liquid (not shown) containing polishing grains is supplied during polishing.

FIG. 1 shows a state in which a work is held by a work holding mechanism and is polished by a polishing pad. The work holding mechanism (10) consists of a holding base (11) and a hollow part (1
3) having a cylindrical rotating shaft (12), a plate member (14) composed of a central portion (14a) and a peripheral portion (14b), a lip seal (18), and a retainer ring (21); The disk-shaped work (3) is held. A polishing pad (28) for polishing the work (3) is attached to a surface plate (29). The work (3) is in the form of a disk having a diameter of 200 mm. The plate member (14) also has a disk shape with a diameter of 200 mm as a whole. The lip seal (18) has a width of 5 mm.

FIG. 1 further shows an infrared radiation thermometer (30), optical filters (38a, 38b), a switch (39), and an arithmetic processing unit (40). These are provided for measuring the polishing temperature.

The holding base (11) is a basic structural member constituting the entire work holding head of the work holding mechanism.
It corresponds to a member for attaching a member such as a plate member. The holding base (11) can be said to be the main body of the work holding head.

The rotating shaft portion (12) is a cylindrical portion having a hollow portion (13) for transmitting infrared rays emitted from the surface to be polished of the work and transmitted through the work. Hollow part (13)
(Horizontal section) has the same cross-sectional shape as the infrared transmitting portion (16) provided on the plate member (14). The rotating shaft (12) is connected to driving means (not shown) so as to be rotatable. In the embodiment shown, the cross section of the hollow part (13) is a circle having a diameter of 30 mm.

An opening (15) having an annular step (15a) is formed in the center of the plate member (14). The opening (15) extends through the entire thickness of the plate member (14). The step (15a) is for mounting the infrared transmitting portion (16), and the infrared transmitting portion (16) is provided with the plate member (14) by the holding plate (26) in the step (15a).
It is fixed to. The infrared transmitting portion (16) needs to be fixed so as not to leak when a fluid is supplied to the space (31) formed by the plate member (14), the work (3) and the lip seal (18). There is.

The infrared transmitting portion (16) is formed of a material (for example, fluorite) that transmits infrared rays emitted from the polished surface of the work and transmitted through the work. In the illustrated embodiment, the infrared transmitting portion (16) is a circular plate having a diameter of 30 mm, and its center is located on the center line k of the work holding mechanism.

The lip seal (18) is arranged so as to be located on the back surface of the peripheral portion of the work, and serves to seal the space (31) to the outside. Lip seal (18)
May be, for example, an O-ring made of an elastic material, or a narrow annular sheet made of an elastic material (for example, Suva 400 (trade name) manufactured by Rodel Nitta).

The space (31) is defined by the plate member (14), the work (3) and the lip seal (18). Fluid is supplied to the space (31) via a fluid pipe (37) provided in the holding base (11) and a fluid pipe (14e) provided in the plate member (14). It has become. When the fluid is supplied to the space (31), the fluid presses the central portion of the work (the portion where the lip seal (18) is not in contact in FIG. 1) against the polishing pad (28).

In the illustrated embodiment, the plate member (1
4) consists of two parts, a central part (14a) and a peripheral part (14b). The peripheral plate member (14b) is a diaphragm (2
0) so as to be movable in the pressing direction. A balloon-like elastic body is provided on the back side of the peripheral plate member (14b). In the illustrated embodiment, the elastic sheet (19) and the holding base (11) form a space (102) to constitute a balloon-like elastic body. When compressed air is supplied as a fluid to the space (102) through the fluid conduit (27), the elastic sheet (19) constituting the balloon-like elastic body expands downward. In the illustrated embodiment, the peripheral plate member (14b) is an annular member having a width of 25 mm.

When the elastic sheet (19) constituting the balloon-like elastic body is inflated by the compressed air, the peripheral plate member (14b) and the lip seal (18) are displaced, so that the peripheral edge of the work (3) becomes a polishing pad ( 28) is pressed. That is, the pressure of the compressed air in the space portion (102) of the balloon-like elastic body is transmitted to the work (3) via the peripheral plate member (14b) and the lip seal (18), whereby the peripheral portion of the work (3) is formed. Is pressed against the polishing pad (28).

Since the lip seal (18) is for exclusively preventing leakage of the fluid when the fluid is supplied to the space (31), the contact between the lip seal (18) and the work (3). The area is small, and the area of the work pressed through the lip seal (18) is extremely small. When it is desired to increase the area of the work pressed by the peripheral plate member, a sheet-like member that contacts the work over a wider area may be used as the lip seal.

In the illustrated embodiment, the elastic sheet (19) constituting the balloon-like elastic body is an annular sheet (for example, a neoprene rubber sheet having a thickness of 0.1 mm). The elastic sheet (19) has an inner peripheral portion and an outer peripheral portion each formed between an annular holding plate (24b, 24c) and a holding base (11).
It is fixed by bolting so that fluid (air) does not leak. When the pressure of the compressed air supplied to the space portion (102) of the balloon-like elastic body is transmitted to the peripheral plate member, the balloon-like elastic body (the elastic sheet (19) in the illustrated embodiment) is not inflated. May not be in contact with the peripheral plate member.

At the same time as the peripheral plate member (14b) is displaced, the free portion of the diaphragm (20) bends. In the illustrated embodiment, the diaphragm (20) is an annular elastic sheet (for example, a neoprene rubber sheet having a thickness of 0.1 mm).
It is. The inner periphery of the diaphragm (20) is fixed by bolting between the plate member (25c) and the holding base (11), and the outer periphery thereof is fixed to the peripheral plate member (14b). The member (14b) is held.
Specifically, the outer peripheral portion of the diaphragm (20) is formed by connecting the peripheral plate member (14b) to the upper portion (14c) and the lower portion (14c).
d) divided into two parts, and a diaphragm (2
0), and fixed by bolting from the upper part (14c). Therefore, the bending portion of the diaphragm (20) is a portion located between the holding base (11) and the peripheral plate member (14b).

The retainer ring (21) is held movably in the pressing direction by a diaphragm (22), like the peripheral plate member (14b). The diaphragm (22) is an annular metal plate (for example, a stainless steel plate or a Hastelloy plate having a thickness of 0.1 mm). A balloon-like elastic body is provided on the back side of the retainer ring (21). In the illustrated embodiment, the holding base (11) and the elastic sheet (2
3) form a space (104) to constitute a balloon-like elastic body. When compressed air is supplied as fluid to the space (104) through the fluid conduit (36), the elastic sheet (23) constituting the balloon-like elastic body expands downward.

When the elastic sheet (23) constituting the balloon-like elastic body is expanded by the compressed air, the retainer ring (21) is displaced and pressed against the polishing pad (28). That is, the pressure of the compressed air in the space (104) of the balloon-like elastic body is transmitted to the retainer ring (21), and the retainer ring (21) is pressed against the polishing pad (28).

In the illustrated embodiment, the elastic sheet (23) constituting the balloon-like elastic body is an annular sheet (for example,
0.1 mm thick neoprene rubber sheet). The inner peripheral portion and the outer peripheral portion of the elastic sheet (23) are fixed between the annular holding plates (24d, 24e) and the holding base (11) by bolting so that fluid (air) does not leak. I have. As long as the pressure of the compressed air supplied to the space (104) of the balloon-like elastic body is transmitted to the retainer ring, the balloon-like elastic body (the elastic sheet (23) in the illustrated embodiment) is not inflated. It does not have to be in contact with the retaining ring.

When the retainer ring (21) is pressed, the free portion of the diaphragm (22) bends at the same time. The outer periphery of the diaphragm (22) is fixed by bolting between the plate-like member (25e) and the holding base (11), and the inner periphery is an upper part (21a) of the retainer ring (21) and a lower part. The retainer ring (21) is held fixed between the portion (21b). Therefore, the bending portion of the diaphragm (22) is a portion located between the holding base (11) and the retainer ring (21).

The polishing temperature is measured by an infrared radiation thermometer (30) arranged on the center line k (rotation axis) of the work holding mechanism (10).
And the arithmetic processing unit (40). The radiation thermometer (30) is an infrared ray (indicated by a dashed white arrow in the drawing) that has passed through the shaft portion (12) of the work holding mechanism (10), and includes two optical filters (38a, 38b). The amount of infrared radiation transmitted through any one of the above is measured. The optical filter (38a) is a high-wavelength cut filter that transmits infrared rays in a wavelength range (for example, a wavelength range of 8 μm or less) that transmits the Si wafer. The optical filter (38b) is a short wavelength cut filter that transmits infrared rays in a wavelength range that does not transmit through the Si wafer (for example, a wavelength range of 8 μm or more). The switching device (39) slides the optical filters (38a, 38b), and switches one of the filters to the shaft portion (12).
Is located on the optical path of the infrared light that has passed. During polishing, switching of the optical filters (38a, 38b) is generally performed alternately. The switching is performed, for example, every 1-2 seconds. Data on the amount of infrared radiation in the two wavelength ranges is sent to the arithmetic processing unit (40). The arithmetic processing unit (40) is connected to the switch (39), and the infrared radiation thermometer (30)
The optical filter recognizes which data is transmitted from the optical filter. The arithmetic processing device (40) performs an arithmetic operation based on information on the optical filter and data from the infrared radiation thermometer (30) to obtain a polishing temperature.

The infrared radiation thermometer (30) has a rotating shaft (1).
The infrared detecting section is always arranged above the work holding mechanism on the center line k (rotary axis) of the work holding mechanism above 2), and the radiation amount of the infrared light taken out from the center of the work is always measured. In order to ensure such an arrangement, the infrared radiation thermometer (30) moves together with the center line k when the center line k moves due to, for example, swinging of the work holding mechanism. In the illustrated embodiment, the infrared radiation thermometer (30) is arranged such that the infrared detection unit is located 80 cm above the surface of the polishing pad.

For polishing, the work (3) is polished to a polishing pad (28).
This is carried out by moving relative to. At this time, the retainer ring (21) is pressed against the polishing pad (28) before starting the relative movement so that the work (3) does not rattle or jump out of the work holding head. As a method of relatively moving the work (3) with respect to the polishing pad (28), there is a method of making the platen (29) move eccentrically in a small circle (or orbital). The revolution diameter and speed of the eccentric small circular motion are determined according to the type of the work and the polishing pad. For example, the revolving diameter may be 5 mm and the relative speed may be 1000 mm / sec.

Next, control of the processing pressure and control of the polishing temperature will be described with reference to FIG. The work holding mechanism and the polishing pad shown in FIG. 2 are the same as those described with reference to FIG. As shown in FIG. 2, the fluid conduits (27,
36, 37) are precision electronic regulators (32, 33,
34) is connected.

The precision electronic regulators (32, 33) control the pressure of compressed air supplied to the space (102, 104) of each balloon-like elastic body. Precision electronic regulator (34)
Controls the pressure of the compressed air supplied to the space (31). Each precision electronic regulator is independent, so that the processing pressure at the center and the periphery of the work and at the retainer ring can be adjusted differently. Each of the precision electronic regulators (32, 33) is connected to a pressure sensor (not shown) for measuring a processing pressure generated when the periphery of the work (3) and the retainer ring (21) are pressed against the polishing pad (28). ing. The precision electronic regulator (34) is connected to a pressure sensor (not shown) for measuring a processing pressure generated when a central portion of the work (3) is pressed. Each pressure sensor is disposed between each precision electronic regulator and the balloon-like elastic body or the work, and measures the pressure of the fluid in the space (102, 104) or space (31) of the balloon-like elastic body, The processing pressure is calculated from a relational expression between the pressure of the fluid in each of the space portions (102, 104, 31) and the processing pressure which has been experimentally obtained in advance.

The balance controller (35) controls the balance of the processing pressure in each part of the work. Specifically, based on the processing pressure information transmitted from the pressure sensor via the precision electronic regulators (32, 33, 34), the controller (35) controls each precision electronic device to obtain a predetermined processing pressure balance. Give instructions to the regulator. The precision electronic regulators (32, 33, 34) supply compressed air adjusted to an appropriate pressure based on an instruction from the balance controller (35).

The polishing temperature obtained by the processing unit (40) is sent as a signal to the temperature controller (41). From the difference between the measured polishing temperature and the target value (desired polishing temperature), the temperature controller (41) requests the balance controller (35) to change the processing pressure so that the polishing temperature becomes the target value. Send That is, in the illustrated embodiment, the polishing temperature is controlled by changing the processing pressure as a process parameter. The balance controller (35) determines the balance of the processing pressure based on the signal, and controls each precision electronic regulator (32, 33, 3).
Give instructions to 4). Each precision electronic regulator (32, 3
3, 34) adjusts the pressure of the compressed air based on the instruction.

In the illustrated control system, a signal transmitted from the temperature controller (41) to the controller (35) is monitored by a polishing end point detector (43). When the polishing end point detector (43) detects a signal requesting that the processing pressure be changed by a predetermined amount or more, the polishing end point detector (43) sends a signal instructing the processing pressure to be zero to the balance controller (35). send. In accordance with this instruction, the balance controller (35) gives an instruction to each precision electronic regulator (32, 33, 34) to reduce the pressure of the compressed air to zero, thereby completing the polishing.

In this control system, the control element for changing the processing pressure is a precision electronic regulator (32, 3
3, 34) and the balance controller (35). The balance controller (35) measures the processing pressure,
The pressure balance is controlled based on an instruction from the temperature controller (41) and an instruction from the polishing end point detector (43).

This control system is provided with a cooling means (not shown) as required. The cooling means is connected to the temperature controller (41), and cools the polishing pad (28) according to an instruction from the temperature controller (41). The cooling of the polishing pad (28) is performed so that the temperature of the polishing pad (28) heated by the polishing of the work is set to a predetermined temperature after the work is separated from the polishing pad and before the next work is polished. Will be implemented.

Next, the polishing method of the present invention, which is performed while measuring and maintaining the polishing temperature at a predetermined temperature, will be described in more detail.

First, using a precision electronic regulator (33), a low pressure (for example, 4.9 kPa-Gauge (0.05 kgf / cm ^2-
Gauge)) is used to expand the elastic sheet (23) constituting the balloon-like elastic body. As a result, the retainer ring (21) is moved in the pressing direction, and the retainer ring (2
The surface of (1) protrudes below the surface of the lip seal (18), and when holding the work, the retainer ring (21)
Is positioned below the work surface.
Then, a loading / unloading device (for example, a robot: not shown)
Then, the work (3) is carried into the wafer holding portion of the work holding mechanism, and the operation of the work holding mechanism is started.
Vacuum 1). As a result, the work (3) is attracted to the lip seal (18).

After the loading / unloading device is retracted, the work (3)
Is located above the polishing pad (28). Then, using a precision electronic regulator (33), low pressure (for example, 9.8)
The balloon-like elastic sheet (23) is inflated with compressed air of kPa-Gauge (0.1 kgf / cm ² -Gauge), and the surface of the retainer ring (21) comes into contact with the polishing pad (28). Move up to At this time, a polishing liquid (not shown) is supplied on the polishing pad (28) in advance. When the retainer ring (21) contacts the polishing pad (28), the retainer ring (21) is pushed upward by the polishing pad (28) and rises slightly (for example, 0.01 mm).

Next, the space (31) is subjected to a positive pressure (for example, 9.8 kPa-Gauge) by a precision electronic regulator (34).
(0.1 kgf / cm ² -Gaug) and pressure controlled by a precision electronic regulator (32) (for example, 9.8 kPa-Gauge (0.1 kgf / cm ² -Gaug)).
e)) is supplied to the space (102) of the balloon-like elastic body, and the work (3) is pressed against the polishing pad (28). By this operation, the work (3) and the retainer ring (2
1) are both pressed by the polishing pad (28), and the pressing is balanced.

Subsequently, the work (3) is polished to the polishing pad (2).
Move relative to. As a method of relatively moving the work (3) with respect to the polishing pad (28), there is a method of performing a small eccentric circular motion (or orbital motion) of the platen (29) to which the polishing pad is attached. The revolution diameter and speed of the eccentric small circular motion are determined according to the type of the work and the polishing pad. For example, the revolving diameter is 5m
The platen (29) can be driven using a driving device (not shown) with the relative speed of m and the relative speed being 1000 mm / sec.

The relative speed of the work (3) is increased gradually (for example, for 10 seconds) from the start of the movement to a predetermined value. While increasing the speed, the balance controller (35) controls the pressure balance to a preset value,
The pressure of the compressed air is adjusted to a predetermined pressure (for example, about 39.2 kPa-Gauge) by a precision electronic regulator (32, 33, 34).
(0.4 kgf / cm ² -Gauge)). Thereby,
Work (3) surface (polished surface) and retainer ring (2
The polishing process proceeds while the surface of 1) is held on the same surface. During polishing, the polishing liquid is continuously supplied to the polishing surface of the polishing pad (28).

The polishing rate (polishing amount per unit time) of the work (3) is determined by the processing pressure and the relative speed. Therefore, during polishing, precision electronic regulator (32)
Adjusts the pressure of the compressed air supplied to the space (102) of the balloon-like elastic body to adjust the polishing rate of the peripheral portion of the work (3). The precision electronic regulator (34) adjusts the pressure supplied to the space (31) to adjust the polishing rate at the center of the work (3).

The precision electronic regulator (33) adjusts the pressure of the compressed air supplied to the space (104) of the balloon-like elastic body, and the retainer ring (21) adjusts the polishing pad (28).
To control the pressure applied to When the retainer ring (21) is pressed, the compression deformation state of the polishing pad (28) near the outer edge of the work (3) changes. Therefore, by changing the pressure applied by the retainer ring (21) to the polishing pad (28), the polishing rate at the outer edge of the work (3) can be changed to prevent edge sagging at the outer edge of the work (3). .

The balance controller (35) controls the precision electronic regulators (32, 33, 34) to change the pressure balance. By changing the pressure balance, it is possible to change the polishing rate of the central portion, the peripheral portion and the outer edge of the work (3), and consequently the polishing profile. The polishing profile is preferably changed so that the work surface is polished uniformly.

During the polishing, since the peripheral plate member (14b) and the retainer ring (21) are held by the diaphragms (20, 22), the positional relationship between the holding mechanism (10) and the polishing pad (28) is reduced. Any changes or tilts between the two are compensated by the diaphragm, so that the pressure balance is less likely to change. In addition, the retainer ring (21) is pressed against the polishing pad (28), thereby preventing the work (3) from rattling. The work (3) does not jump out of the work holding head.

According to the illustrated embodiment, the diaphragm (2
Since the inner and outer peripheral portions of 2) are fixed, during polishing, for example, the work (3) is displaced in the horizontal direction due to frictional force and comes into contact with the retainer ring (21).
Also, due to the frictional force applied to the retainer ring (21),
Even if a force for displacing a part of the retainer ring (21) in the horizontal direction is applied, the retainer ring (21) does not significantly displace in the horizontal direction. This is a retaining ring (21)
Is held around the entire circumference by an annular diaphragm (22) having an axially symmetric structure with the rotation axis of the work holding mechanism as the axis of symmetry. That is, retainer ring (21)
Even if such a force is applied to the retainer ring (21), the diaphragm (22) is elastically deformed, and a force in the opposite direction with respect to the axis of symmetry can be applied to the retainer ring (21). No significant displacement in the horizontal direction,
The center of the retainer ring (21) is the work holding mechanism (1
0) can always coincide with the center.

While the workpiece is being polished while controlling the processing pressure, the infrared radiation thermometer (30) alternately measures the amount of infrared radiation in two different wavelength ranges transmitted through the optical filters (38a, 38b). Measure. The measured radiation amount data is sent to the arithmetic processing unit (40). The arithmetic processing unit (40) calculates the polishing temperature from the data of the radiation amount.

The polishing temperature is sent as a signal from the arithmetic processing unit (40) to the temperature controller. The temperature controller (41) obtains an excess or deficiency of the processing pressure based on a difference between a preset optimum polishing temperature and the measured polishing temperature and a relationship between the polishing temperature and the processing pressure. Give instructions to increase or decrease pressure. The balance controller (35) calculates the pressure balance according to this instruction, and calculates the precision electronic regulator (3
2, 33, 34) to change the processing pressure as desired. By changing the processing pressure in this way, the polishing temperature is maintained at the optimum polishing temperature. The optimum polishing temperature differs depending on the type of the work and the like. For example, when polishing an interlayer insulating film made of SiO ₂ , the optimum polishing temperature is about 70 ° C.

In the illustrated embodiment, the control system for controlling the processing pressure forms a closed loop, and the polishing end point is detected based on a signal transmitted from the temperature controller (41) to the balance controller (35). . The polishing end point detector (43) detects a signal that requires a change in the processing pressure by a predetermined amount or more, for example, due to a sudden change in the polishing temperature due to a change in the material exposed on the surface to be polished. It is determined that the process has been completed. When the polishing is completed, the polishing end point detector (43) issues an instruction necessary for terminating the polishing to the balance controller (35) and the drive of the platen (29) (and the work holding mechanism when the work holding mechanism is moving). Drive device).

When the polishing process is completed, the relative movement of the work (3) with respect to the polishing pad (28) is stopped in accordance with the instruction of the polishing end point detector (43), and at the same time, the work (3) and the retainer ring (21) are driven at a low pressure. (For example, 4.
The balance controller (35) controls the precision electronic regulators (32, 33, 34) so that the polishing pad (28) is pressed with 9 kPa-Gauge (0.05 kgf / cm ² -Gauge). As a result, the holding mechanism (10) rises to a position where the work loading / unloading device can operate, as shown in FIG. 3, while lightly pressing the work (3) against the polishing pad (28). Then, using the loading / unloading device, the polished work is carried out, and the unpolished work is carried in.

As shown in FIG. 2, the infrared radiation thermometer (3
0) is the work holding mechanism (10) on the back side of the work (3)
, So that loading and unloading of the work is not hindered.
Therefore, in the polishing method of the present invention, the workpiece can be polished from the start to the end of the polishing without affecting the polishing process while measuring the polishing temperature more accurately.

During polishing, the infrared radiation thermometer (30) is located on the back side of the work (3) and does not contact the work and the polishing pad, so that it does not affect the processing pressure. Therefore, according to the illustrated embodiment, the polishing temperature can be measured more accurately while the polishing proceeds uniformly at the processing pressure controlled by the controller and the precision electronic regulator.

As shown in FIG. 3, an infrared radiation thermometer (3
0) The temperature of the polishing surface of the polishing pad (28) can be measured during the loading and unloading of the work. If the measured temperature of the polishing surface of the polishing pad is, for example, too high, the polishing pad may be cooled by a suitable cooling means (eg, an air blaster) (44). Thereby, the temperature of the polishing pad can be set to a desired temperature before the next work is polished.

The polishing temperature measured during polishing gives information on the polishing rate of the work. When the polishing temperature exceeds a predetermined value, it is preferable that the processing pressure is immediately adjusted by a precision electronic regulator so that a predetermined polishing rate is always obtained.

FIG. 4 shows another example of the polishing apparatus of the present invention.
In FIG. 4, the optical filters (38a, 38) shown in FIG.
Instead of b), a wavelength-selective reflector (42) is provided. The reflection plate (42) reflects infrared rays in a wavelength range (for example, a wavelength range of 4 μm or less) that transmits the work, and transmits infrared rays in a wavelength range (for example, a wavelength range of 4 μm or more) that does not transmit the work. The amount of infrared radiation transmitted through the reflector (42)
It is measured by an infrared radiation thermometer (30a) arranged on the center line k (rotation axis) of the work holding mechanism (10). The amount of infrared radiation reflected by the reflector (42) is measured by an infrared radiation thermometer (30b). Infrared radiation thermometer (30a, 30
Based on the radiation amount measured in b), an arithmetic processing unit (4
In (0), the polishing temperature is calculated. Other members and elements are the same as those shown in FIG.

Each of the illustrated polishing methods is an example of an embodiment of the present invention, and the scope of the present invention is not limited to this embodiment. Further, these embodiments may be modified as needed. For example, in the operation of the work holding mechanism, the method of loading and unloading the work, the pressure of compressed air, and the like are appropriately selected according to the type of the work and the polishing pad. The structure of the work holding mechanism can be changed as needed.

[0175]

As described above, in the polishing temperature measuring method of the present invention, at least two infrared rays having different wavelengths or wavelength ranges are extracted at the back side of the center of the work, and the extracted wavelengths or wavelength ranges are extracted. Is measured in a non-contact manner, and the temperature of the surface to be polished of the work is measured as the polishing temperature from the amount of infrared radiation of each wavelength or wavelength range. With such a feature, it is possible to continuously and accurately measure the temperature of the currently polished predetermined portion without locally changing the processing pressure, excluding the influence of infrared rays which may be a disturbance. Since the temperature is measured without contact, there is no measurement error due to the heat capacity of the measuring instrument.

In particular, as infrared rays of at least two different wavelengths or wavelength ranges, at least one infrared ray of a wavelength or a wavelength range that transmits a work is extracted, and at least one infrared ray of a wavelength or a wavelength range that does not transmit a work is extracted. If the polishing temperature is measured, the influence of disturbance can be eliminated more accurately, and the polishing temperature can be measured more accurately.

Therefore, if the polishing is performed while measuring the polishing temperature by the polishing temperature measuring method of the present invention, the workpiece can be polished while measuring the polishing temperature more accurately than in the conventional polishing method. The polishing rate can be made constant by more appropriately controlling the polishing temperature. That is, the polishing method of the present invention provides a product which is uniformly polished and has a high yield.

The polishing temperature measuring method and the polishing method according to the present invention include a plate member having a cylindrical shaft portion and an infrared ray transmitting portion;
By using a polishing device having a work holding mechanism including a lip seal attached to a plate member so as to be located on the back surface of the peripheral portion of the work, and by measuring the amount of infrared radiation through the infrared transmitting portion and the shaft portion It is preferably implemented. When the work is held by the work holding mechanism, a space is formed by the plate member, the lip seal, and the work. If a fluid is supplied to the space, the work can be pressed against the polishing pad by the pressure of the fluid. Therefore, if this work holding mechanism is used, a more accurate polishing temperature can be measured while polishing the work in a state where the work is pressed against the polishing pad.

The polishing method of the present invention is preferably performed by the polishing apparatus including the work holding mechanism of the present invention and at least two devices for extracting infrared rays having different wavelengths or wavelength ranges (for example, an optical filter or a wavelength-selective reflector). Is done. According to the polishing apparatus of the present invention, a more accurate polishing temperature can be measured while polishing the work in a state where the work is pressed against the polishing pad.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment of a polishing temperature measuring method and a polishing method of the present invention using a work holding mechanism of the present invention.

FIG. 2 is a schematic diagram showing a polishing temperature control system applicable to the polishing method of the present invention.

FIG. 3 is a schematic view showing a state in which the temperature of the polishing surface of the polishing pad is measured by the polishing temperature measuring method of the present invention when the work is carried in and out.

FIG. 4 is a schematic view showing another example of the embodiment of the polishing temperature measuring method and the polishing method of the present invention using the work holding mechanism of the present invention.

FIGS. 5A and 5B are schematic diagrams each showing a method of switching between two optical filters.

[Explanation of symbols]

3 ... work (semiconductor wafer), 10 ... work holding mechanism,
11 ... holding base, 12 ... rotating shaft, 13 ... hollow part, 14 ... plate member, 15 ... opening, 16 ... infrared transmission part, 18 ...
Lip seal, 19 ... elastic sheet, 20 ... diaphragm,
21 ... retainer ring, 22 ... diaphragm, 23 ... elastic sheet, 24 ... holding plate, 25 ... plate-like member, 26 ... holding plate,
27 ... Fluid line, 28 ... Polishing pad, 29 ... Surface plate, 30, 3
0a, 30b ... infrared radiation thermometer, 31 ... space, 32, 3
3, 34 ... precision electronic regulator, 35 ... balance controller, 36 ... fluid line, 37 ... fluid line, 38a, 38
b ... Optical filter, 39 ... Switcher, 40 ... Processing unit, 41 ... Temperature controller, 42 ... Reflector, 43 ...
Polishing end point detector, 102, 104 ... space.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/304 621 H01L 21/304 621D 622 622K 622R F-term (Reference) 3C029 EE03 3C034 AA13 BB71 BB93 CA02 CA05 CA19 CA22 CB01 DD01 DD10 3C058 AA07 AA12 AB04 AC02 BA05 BA08 BB02 BB04 BC01 CA01 DA12 DA17

Claims (13)

[Claims] When polishing a work surface by moving the work relative to the polishing pad while pressing the work against the polishing pad, the amount of radiation is at least two different wavelengths or infrared wavelengths of the work. The infrared light that changes according to the temperature of the surface to be polished is extracted from the back side of the center of the work, and the amount of emitted infrared light of each wavelength or wavelength range is measured in a non-contact manner. A polishing temperature measuring method for measuring the temperature of the surface to be polished of a work from the radiation amount of the workpiece. 2. The polishing temperature measuring method according to claim 1, wherein: (1) at least two infrared rays having different wavelengths or wavelength ranges; (B) at least one of the infrared rays radiated from the part emitting the disturbance, the infrared ray A having a wavelength or a wavelength range that does not become a disturbance, or the wavelength. Alternatively, it is taken out from the back side of the central portion of the work so that it is infrared B in the wavelength range including the wavelength range. 2) The radiation amounts Ea and Eb of the infrared rays A and B are measured. 4) The difference between Ea and Ea 'or the difference between Eb and Eb 'From the difference in the temperature of the workpiece to be polished. 3. The infrared ray A is an infrared ray having a wavelength or a wavelength range transmitting the work, or an infrared ray having a wavelength range including the wavelength or the wavelength range, and the infrared ray B is a wavelength or a wavelength range not transmitting the work, or the infrared ray. The polishing temperature measuring method according to claim 2, wherein the infrared ray is infrared light in a wavelength range including a wavelength or a wavelength range. 4. The method of measuring a polishing temperature according to claim 1, wherein: 1) extracting infrared rays α and infrared rays β of two different wavelengths or wavelength ranges; and 2) polishing the workpiece in a system for performing polishing. The temperature Tα of the surface and the temperature Tβ of one part that emits disturbance are changed, and the radiation amount Eα of the infrared ray α at each temperature combination is changed.
And the amount of radiation Eb of infrared β was measured, and
The correlation fα between α, Tα and Tβ, and Eβ, T
The correlation fβ between α and Tβ is obtained in advance, and 3) the radiation amount Eα of the infrared ray α and the radiation amount Eβ of the infrared β are measured while polishing the object to be processed, and a combination of the two measured radiation amounts Eα and Eβ Determining the temperature of the surface to be polished of the workpiece based on the correlations fα and fβ. 5. The polishing temperature measuring method according to claim 4, wherein the infrared ray β is an infrared ray having a wavelength or a wavelength range that does not cause disturbance or a wavelength range including the wavelength or the wavelength range. 6. The infrared ray α is an infrared ray having a wavelength or a wavelength range that transmits the work, or an infrared ray having a wavelength range including the wavelength or the wavelength range, and the infrared ray β is a wavelength or a wavelength range that does not transmit the work, or the infrared ray. The polishing temperature measuring method according to claim 5, wherein the infrared ray is infrared light in a wavelength range including a wavelength or a wavelength range. 7. An infrared filter of at least two different wavelengths or wavelength ranges is extracted by at least two optical filters having different transmission wavelength bands, and the amount of emitted infrared light of each extracted wavelength or wavelength range is measured. The polishing temperature measuring method according to any one of the above. 8. The polishing temperature measuring method according to claim 7, wherein the infrared radiation amount of each wavelength or wavelength region is measured by one infrared radiation amount measuring device capable of measuring the infrared radiation amount of each wavelength or wavelength region. . 9. An infrared light path of at least two different wavelengths or wavelength ranges is extracted by extracting a light path of the infrared light into a light path of infrared light of at least two different wavelengths or wavelength ranges by a wavelength-selective reflector. The polishing temperature measuring method according to any one of claims 1 to 6, wherein, among the infrared rays of each wavelength or wavelength range, the radiation amounts of infrared rays of at least two different wavelengths or wavelength ranges are measured. 10. A polishing method for polishing a work surface by moving a work relative to a polishing pad while pressing the work against the polishing pad, wherein the infrared light has at least two different wavelengths or wavelength ranges. Infrared light whose radiation amount changes according to the temperature of the polished surface of the work is extracted from the back side of the central part of the work, and the amount of infrared radiation of each extracted wavelength or wavelength range is measured in a non-contact manner. A polishing method characterized in that a workpiece is polished while measuring a polishing temperature from an amount of infrared radiation in a wavelength range. 11. A work holding mechanism for pressing a work against a polishing pad and holding the work in a plane perpendicular to the pressing direction, the work holding mechanism comprising: a cylindrical shaft portion; a plate member having an infrared transmitting portion; Including a lip seal attached to the plate member so as to be located on the back surface of the peripheral portion, when the work is held, a space is formed by the plate member, the lip seal and the work, and the fluid supplied to the space is A work holding mechanism wherein the work is pressed against the polishing pad by pressure. 12. An apparatus for polishing a surface to be polished of a work with a polishing pad, comprising: (a) the work holding mechanism according to claim 11; and (b) at least two optical filters and optical filters having different transmission wavelength bands. (C) an infrared radiation meter located on the optical path of infrared light that has passed through the optical filter; (d) a platen supporting the polishing pad; and (e) a work relative to the polishing pad. A polishing apparatus having means for moving the polishing apparatus. 13. A device for polishing a surface to be polished of a work with a polishing pad, comprising: (a) a work holding mechanism according to claim 11; and (b) a wavelength selector disposed on the back surface side of the center portion of the work. (C) an infrared radiation meter located on the optical path of at least two of the infrared rays split by the reflector; (d) a platen supporting a polishing pad; and (e) A polishing apparatus comprising means for moving a work relative to a polishing pad.