JP3367496B2 - Polishing body, planarization apparatus, semiconductor device manufacturing method, and semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing body suitable for use in flattening and polishing a semiconductor device in a method for manufacturing a semiconductor device such as ULSI, and a flattening apparatus,
The present invention relates to a semiconductor device manufacturing method and a semiconductor device.

[0002]

2. Description of the Related Art As semiconductor integrated circuits become highly integrated and miniaturized, the number of semiconductor manufacturing process steps is increasing and becoming complicated. Along with this, the surface of semiconductor devices is not always flat. The presence of the step on the surface of the semiconductor device causes disconnection of wiring, local increase in resistance, and the like, resulting in disconnection and reduction in electric capacity.
Further, the insulating film also causes deterioration of withstand voltage and leakage.

On the other hand, with the high integration and miniaturization of semiconductor integrated circuits, the wavelength of the light source of the semiconductor exposure apparatus used for photolithography is shortened, and the numerical aperture of the projection lens of the semiconductor exposure apparatus, so-called NA, is increased. It has become to. As a result, the depth of focus of the projection lens of the semiconductor exposure apparatus has become substantially shallow. In order to cope with the shallow depth of focus, it is required to flatten the surface of a semiconductor device more than ever.

Specifically, in the semiconductor process, the flattening technique as shown in FIGS. 11A and 11B is indispensable. A semiconductor device 124, an interlayer insulating film 122 made of SiO ₂ , and a metal film 123 made of Al are formed on a silicon wafer 121. FIG. 11A shows an example in which the interlayer insulating film 122 on the surface of the semiconductor device is flattened. FIG. 11B shows the metal film 123 on the surface of the semiconductor device.
This is an example of polishing so that a so-called damascene is formed. Chemical mechanical polishing (Chemical Mechanical Polishing) is a method for planarizing the surface of such a semiconductor device.
l Polishing or Chemical Mechanical Planarization,
Below, CMP) technology is widely practiced. Currently C
MP technology is the only way to planarize the entire surface of a silicon wafer.

CMP has been developed based on a mirror polishing method for silicon wafers. FIG. 12 is a schematic configuration diagram of a conventional flattening apparatus used for CMP. The flattening device includes a polishing member 131, an object-to-be-polished holding unit (hereinafter referred to as a polishing head) 132, and an abrasive supply unit 134. Then, a silicon wafer 133, which is an object to be polished, is attached to the polishing head 132, and a polishing agent supply unit 134 supplies a polishing agent (slurry) 135. The polishing member 131 has a polishing plate 137 attached on a surface plate 136.

The silicon wafer 133 is held by the polishing head 132, rocks while being rotated, and is pressed against the polishing body 137 of the polishing member 131 with a predetermined pressure. The polishing member 131 is also rotated so that relative movement with the silicon wafer 133 is performed. In this state, the polishing agent 135 is supplied from the polishing agent supply unit 134 onto the polishing body 137, the polishing agent 135 diffuses on the polishing body 137, and the polishing body 137 is caused by the relative movement of the polishing member 131 and the silicon wafer 133. And the silicon wafer 133, and the polishing surface of the silicon wafer 133 is polished. That is, the polishing member 1
Mechanical polishing due to relative motion between 31 and the silicon wafer 133 and chemical action of the polishing agent 135 act synergistically to achieve good polishing.

The relationship between the polishing amount of a silicon wafer and the above-mentioned polishing conditions is given by an empirical formula called Preston formula shown in (Formula 1).

R = k × P × V (Equation 1) where R is the polishing amount of the silicon wafer, P is the pressure per unit area for pressing the silicon wafer against the polishing body, and V is the relative movement of the polishing member and the silicon wafer. Relative linear velocity,
k is a proportional constant.

By the way, in CMP, the polishing rate varies due to the temperature distribution of the polishing body and the spatial difference in the supply state of the polishing agent. Further, there is a decrease in the polishing rate due to the number of processed sheets due to the change in the surface state of the polishing body, and a difference in the polishing rate due to the individual difference in the polishing body. .

Therefore, instead of the end point determination by time management, there has been proposed a method of determining the end point while in-situ measurement of motor torque, vibration and the like.
These methods use CMP that changes the material to be polished.
(For example, CMP of wiring material, CMP with stopper layer) is effective to some extent. However, in the case of a silicon wafer having a complicated pattern, it may be difficult to determine the end point because the material to be polished changes little. Further, in the case of CMP of the interlayer insulating film, since it is necessary to control the capacitance between wirings, it is required to manage the remaining film thickness, not the polishing end point. It is difficult to measure the film thickness by a method of in-situ measurement of motor torque, vibration, etc., and determining the end point.

In order to solve the above-mentioned problems, recently, in-situ end point detection and in-si detection by optical measurement, particularly reflection spectroscopy, are performed.
Tu film thickness measurement is effective. As shown in FIG. 12, the configuration of in-situ measurement is such that an opening 138 for measurement is provided in the surface plate 136 and the polishing body 137, and the surface of the object to be polished is measured by the device 139 for measuring the polishing state through the opening 138. The method of observation is common. Although not shown in FIG. 12, a transparent window is generally installed in the polishing body 137 or the like to close the opening. By providing the window, the measuring light from the device 139 for measuring the polishing state passes through the window, but it is possible to prevent the abrasive 135 from leaking from the opening 138 to the device 139 for measuring the polishing state.

At the time of polishing, since the abrasive is discharged onto the abrasive body, the observation is performed through the abrasive. Since the polishing agent that is a scatterer attenuates the measurement light, it is preferable that the number of the polishing agents intervening in the measurement optical path is small when performing highly accurate measurement. That is, if there is a step between the surface of the polishing body and the surface of the window on the side of the object to be polished, the polishing agent will accumulate in the window portion and attenuate the measurement light.

So-called polishing pads made of polyurethane foam have been used as polishing bodies. However, the polishing pad made of foamed polyurethane causes the polishing agent to be clogged and the polishing characteristics become unstable. Therefore, in the case of a foamed polyurethane polishing pad, the surface of the foamed polyurethane polishing pad is generally dressed with a diamond grindstone in order to perform stable polishing. Dressing is a process of removing the clogged abrasive and at the same time scraping off the surface of the polyurethane foam polishing pad to create a fresh polishing pad surface.

[0014]

However, at the same time when the polishing body (polishing pad) is scraped off at the time of dressing, the window is damaged and becomes optically opaque, so that in-situ measurement cannot be performed.

The present invention has been made to solve the above problems, and in the case of detecting the polishing end point and measuring the film thickness in-situ in the CMP process, a polishing body having a dressable window and a planarizing apparatus. The purpose is to get.

[0016]

As a result of earnest research, the inventors of the present invention have found that in the case of in-situ measurement, scattering of light by an abrasive, that is, that the distance between a window and a silicon wafer is acceptable to some extent, The present invention has been completed by finding that the window is not scratched even when the abrasive body is dressed.

In other words, in order to solve the above-mentioned problems, the polishing body according to the present invention is such that the polishing agent is interposed between the polishing body installed on the surface plate and the object to be polished. Between the polishing object and the object to be polished, and by relatively moving the object to be polished, the polishing body used in the flattening device for polishing the object to be polished is provided with one or more openings and provided in the openings. The surface of the window on the side of the object to be polished is recessed with respect to the surface of the polishing body, and the amount of the recess is changed stepwise or continuously (claim 1). .

According to the above-mentioned polishing body, when the polishing state of the polishing object is observed by the device for measuring the polishing state by optically observing the polishing surface of the polishing object through the window, the surface is scratched. Use a window that is not marked or the part of the window that is not scratched. Then, when the window or the portion of the window is scratched by dressing or polishing, the polishing state of the polishing object is observed by a device for measuring the polishing state. By switching to the window or window part,
In-situ measurement of the polishing state can be performed, and the frequency of exchanging the polishing body or the window can be reduced. Thereby, the cost required for polishing can be reduced.

Further, it is preferable that the dent amount is changed stepwise because the dent amount is different for each opening. Therefore, when observing the polishing state of the object to be polished by the device for measuring the polishing state, use a window whose opening is not scratched on the surface, and when the window is scratched by dressing or polishing. The in-situ measurement of the polishing state can be performed by switching the observation of the polishing state of the polishing object with the device for measuring the polishing state to the window of the opening with a different dent amount in the initial state and without scratches. it can.

Further, it is preferable that the dent amount is changed stepwise because the dent amount is different in two or more portions within the same opening (claim 3). Thereby, when observing the polishing state of the polishing object by the device for measuring the polishing state, using a portion of the window without scratches,
When the part of the window is damaged by dressing or polishing, the observation of the polishing state of the polishing object by the device for measuring the polishing state is switched to the part of the window where the initial state has a different dent amount and is not scratched. This allows in-situ measurement of the polished state.

Further, it is preferable that the window is a parallel plate-shaped transparent plate, and the window is installed obliquely with respect to the surface of the polishing body so that the amount of the depression is continuously changed. (Claim 4). Therefore, when observing the polishing state of the object to be polished by the device for measuring the polishing state, when the portion of the window that is not scratched is used, and when that portion of the window is scratched by dressing or polishing In-sit of the polishing state by switching the observation of the polishing state of the polishing object with the device for measuring the polishing state to the window part where the dent amount in the initial state is different and there is no scratch
u Can perform measurements.

The minimum dent amount among the dent amounts
dmin is preferably 0 μm <dmin ≦ 400 μm (contract)
Requirement 6). This allows the window to come into contact with the object to be polished.
The window will not be damaged because the Also before
The maximum dent depth dmax is 0 μm <dmax ≤
90% of the thickness of the polished body, and of the windows
The minimum thickness of tmin is tmin ≥ 10% of the polishing body thickness
Is preferably (claim 8). This allows
Since the window and the object to be polished do not come into contact with each other, the polishing
The elephants are not damaged and the windows are not damaged. Furthermore
In addition, the thickness of the window is not too thin, so the window will not be deformed.
Instability in the detection of the polishing end point due to the deformation of the window and the film
Instability in thickness measurement does not occur.

Further, in order to solve the above problems, the present invention
Another aspect of the polishing body according to Ming is installed on a surface plate.
A state in which an abrasive is interposed between the polishing body and the object to be polished
A load is applied between the polishing body and the object to be polished,
Moreover, the object to be polished is polished by moving it relatively.
In the polishing body used for the flattening device for polishing, an opening and
A window installed in the opening, and a surface of the polishing body.
Surface of the window on the side of the object to be polished is recessed with respect to the surface
And the window is a parallel flat plate made by stacking two or more transparent materials.
It is a transparent plate on the plate, the distance between the transparent materials can be separated
They are laminated with a degree of adhesive force (claim 5). The polishing body
According to the method, when observing the polishing state of an object to be polished,
Use a non-scratched window on the
When the window is scratched due to polishing, the top surface of the window is transparent
By peeling the material, cut it into a scratch-free window.
It becomes possible to change the polishing condition and perform in-situ measurement of the polished state.
I can.

Further , the recess amount d0 of the recess is 0 μm <d0
It is preferable that ≦ 400 μm (claim 7). By this
Therefore, the window and the object to be polished do not come into contact with each other.
Will not be hurt. In addition, the dent amount d0 of the dent
Is 0 μm <d0 ≦ 90% of the thickness of the polishing body, and
The thickness t0 of the window is t0 ≧ 10% of the thickness of the polishing body.
Is preferably (claim 9). This allows
Since the window and the object to be polished do not come into contact with each other, the polishing
The elephants are not damaged and the windows are not damaged. Furthermore
In addition, the thickness of the window is not too thin, so the window will not be deformed.
Instability in the detection of the polishing end point due to the deformation of the window and the film
Instability in thickness measurement does not occur.

Further, at least a portion of the transmittance of the window is preferably 22% or more (claim 1
0 ). As a result, the attenuation of the light intensity for measuring the polishing state passing through the window is reduced, so that the accuracy of detecting the polishing end point and the accuracy of measuring the film thickness do not deteriorate.

Further, it is preferable that an antireflection film is formed on the surface of the window opposite to the object to be polished (claim 11 ). This reduces the amount of light reflected on the surface of the window for measuring the polishing state that passes through the window, and reduces the attenuation of the light intensity for measuring the polishing state. The film thickness measurement accuracy does not decrease.

Further, in order to solve the above problems, in the flattening apparatus of the first aspect of the present invention, an abrasive is interposed between the polishing body and the object to be polished, which are installed on the surface plate. In the flattening device for polishing the polishing object by applying a load between the polishing body and the polishing object and relatively moving the polishing object in this state, one or more openings formed in the surface plate. Part, one or more openings formed in the polishing body, and installed in the polishing body, or installed in the surface plate so as to close at least a part of the opening formed in the polishing body. And a device for optically observing the polishing surface of the polishing object through the window to measure the polishing state, and the opening formed in the polishing body and the surface plate. The formed opening overlaps with the surface of the polishing body. On the other hand, the surface of the window on the side of the object to be polished is dented, and the dent amount changes stepwise or continuously (claim 12 ).

According to the flattening apparatus, the apparatus for measuring the polishing state by optically observing the polishing surface of the polishing object through the window allows the surface to be observed when observing the polishing state of the polishing object. An object to be polished by a device that uses a non-scratched window or a non-scratched part of the window and measures the polishing state when the window or that part of the window is scratched by dressing or polishing In-situ measurement of the polishing state can be performed by switching the observation of the polishing state to a window or a window part where the dent amount in the initial state is different and is not scratched, and the replacement frequency of the polishing body or window can be changed. Can be reduced. Thereby, the cost required for polishing can be reduced.

Further, it is preferable that the recess amount is changed stepwise by varying the recess amount for each of the openings formed in the polishing body (claim 13 ). Therefore, when observing the polishing state of the object to be polished by the device for measuring the polishing state, use a window whose opening is not scratched on the surface, and when the window is scratched by dressing or polishing. The in-situ measurement of the polishing state can be performed by switching the observation of the polishing state of the polishing object with the device for measuring the polishing state to the window of the opening with a different dent amount in the initial state and without scratches. it can.

In addition, 2 in the opening having the same amount of depression is used.
It is preferable that the dent amount is changed stepwise due to the difference in the above portions (claim 14 ). Therefore, when observing the polishing state of the object to be polished by the device for measuring the polishing state, when the portion of the window that is not scratched is used, and when that portion of the window is scratched by dressing or polishing The in-situ measurement of the polishing state can be performed by switching the observation of the polishing state of the polishing object with the device for measuring the polishing state to the window part where the dent amount in the initial state is different and there is no scratch .

Further, it is preferable that the window is a parallel plate-shaped transparent plate, and the window is installed obliquely with respect to the surface of the polishing body, so that the recess amount is continuously changed. (Claim 15 ). Therefore, when observing the polishing state of the object to be polished by the device for measuring the polishing state, when the portion of the window that is not scratched is used, and when that portion of the window is scratched by dressing or polishing In-sit of the polishing state by switching the observation of the polishing state of the polishing object with the device for measuring the polishing state to the window part where the dent amount in the initial state is different and there is no scratch
u Can perform measurements.

Further, the polishing state of the window is measured.
The amount of depression d in the portion through which the light from the device to be determined passes is 0.
It is preferable that μm <d ≦ 400 μm (claim 17).
This prevents the window from coming into contact with the object to be polished.
Therefore, the window is not damaged. In addition, the amount of the dent
The maximum amount of depression dmax is 0 μm <dmax ≤
90% of the thickness, and of the thickness of the window
The minimum thickness tmin is tmin ≧ 10% of the thickness of the polishing body.
The length is preferably (claim 19). By this
Therefore, the window does not come into contact with the object to be polished,
The object to be polished is not damaged and the window is not damaged. It
In addition, the window may be deformed because it is not too thin.
And the instability of the polishing end point detection due to the deformation of the window
Instability in film thickness measurement does not occur.

Further, in order to solve the above problems, the present invention
The flattening device according to the second aspect of the present invention is installed on the surface plate.
A polishing agent was interposed between the polishing body and the object to be polished.
In this state, apply a load between the polishing body and the object to be polished.
And by relatively moving the object to be polished,
Formed on the surface plate in a flattening device for polishing
An opening, an opening formed in the polishing body, and the polishing
Installed on the body or formed on the abrasive body
The platen is installed so as to close at least a part of the opening.
A window that is placed, and polishing of the object to be polished through the window
Equipped with a device that optically observes the surface and measures the polishing state.
Shape the opening and the surface plate formed in the polishing body.
The formed opening overlaps with the opening of the polishing body.
The surface of the window on the side of the object to be polished is recessed with respect to the surface
And the windows are parallel with two or more transparent materials laminated together.
It is a flat plate-shaped transparent plate and the transparent materials can be separated from each other.
They are laminated with a moderate adhesive force (claim 16). to this
Therefore, when observing the polishing state of the object to be polished, scratches on the surface
For dressing or polishing using windows without
More transparent material on the top surface of the window when the window is scratched
Switch to a scratch-free window by peeling off the
It becomes possible to perform in-situ measurement of the polishing state.
You can

Further , the recess amount d0 of the recess is 0 μm <d0
It is preferable that ≦ 400 μm (claim 18). to this
Therefore, since the window and the object to be polished do not come into contact with each other,
The windows will not be damaged. In addition, the dent amount d0 of the dent
Is 0 μm <d0 ≦ 90% of the thickness of the polishing body, and
The thickness t0 of the window is t0 ≧ 10% of the thickness of the polishing body.
Is preferred (claim 20). This makes the window
The object to be polished does not come into contact with the object to be polished.
No more damaging things and windows. further,
The thickness of the window is not too thin, so the window will not be deformed.
Of the end point of polishing due to the deformation of the window
Instability of measurement does not occur.

Further, it is preferable that the window is made of resin having a polishing characteristic equivalent to that of the polishing body (claim 21 ). Accordingly, even when the window comes into contact with the silicon wafer that is the object to be polished, the window does not scratch the polishing surface of the silicon wafer or cause uneven polishing.

Further, in order to solve the above problems, in the flattening apparatus of the third aspect of the present invention, an abrasive is interposed between the polishing body and the object to be polished which are installed on the surface plate. In the flattening device for polishing the polishing object by applying a load between the polishing body and the polishing object and relatively moving the polishing object in this state, one or more openings formed in the surface plate. Section, one or more openings formed in the polishing body, a window installed so as to close at least a part of the opening formed in the polishing body, and the object to be polished through the window. And a moving device for moving the position of the surface of the window on the side of the object to be polished, the opening being formed in the polishing body. And the opening formed on the surface plate overlap, The writing window is installed on the surface plate through the moving device (claim 22 ).

According to the flattening device, when the polishing state of the polishing target is observed by the device for measuring the polishing state by optically observing the polishing surface of the polishing target through the window, By controlling the distance between the surface on the side of the object to be polished and the polishing surface of the object to be polished, the surface of the window on the side of the object to be polished is not scratched by dressing or polishing, and in-situ measurement of the polishing state can be performed. Therefore, it is possible to reduce the frequency of exchanging the polishing body or the window. Thereby, the cost required for polishing can be reduced.

Further, an apparatus for detecting a distance between the surface of the window on the side of the object to be polished and the polishing surface of the object for polishing, a device for detecting a wear state of the polishing body, or a device for detecting both of them is provided. It is preferable to further have (Claims)
23 ). Thus, the distance between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished can be detected.

Further, it is preferable to further include a control device for controlling a gap between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished (claim 24 ). Accordingly, the controller can control the distance between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished.

Further, the control device predicts a wear amount of the polishing body from the polishing condition, the polishing time, the dressing condition and the dressing time, and polishes the surface of the window on the side of the polishing target and the polishing target. It is preferable to control the distance to the surface (claim 25 ). This prevents the window from being scratched by polishing and dressing.

Further, the control apparatus preferably the distance between the polishing surface of the polishing object side surface and said object to be polished of the window to control the moving device to be constant (Claim 26 ). This prevents the window from being scratched by polishing and dressing.

Further, it is preferable that the control device controls a gap between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished in synchronization with rotation of the surface plate (claim 27 ). ). This prevents the window from being scratched by polishing and dressing.

The distance d between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished is 0 μm ≦ d ≦ 400.
It is preferably μm (claim 28 ). This prevents the window from being scratched by polishing and dressing.

The distance d between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished is 0 μm ≦ d ≦ 90% of the thickness of the polishing body, and The thickness t of the window is preferably t ≧ 10% of the thickness of the polishing body (claim 29 ). This prevents the object to be polished and the window from being damaged by polishing and dressing. Furthermore, because the window is not too thin,
The window is not deformed, and the instability of detection of the polishing end point and the instability of film thickness measurement due to the deformation of the window do not occur.

Further, the light emitted from the device for measuring the polishing state passes through the window, passes through the polishing agent between the window and the polishing object, and is emitted on the polishing surface of the polishing object. Reflecting, passing through the polishing agent between the window and the object to be polished again, passing through the window again, returning to the apparatus for measuring the polishing state, and emitting from the apparatus for measuring the polishing state It is preferable that the ratio of the intensity of light returning to the device for measuring the polishing state to the intensity of light is 5% or more (claim 30 ). As a result, the intensity of the light returning to the apparatus for measuring the polishing state becomes sufficient to measure the polishing state, so that the accuracy of detecting the polishing end point and the measurement accuracy of the film thickness by the apparatus for measuring the polishing state are reduced. Disappear.

Further, it is preferable that an antireflection film is formed on a surface of the window opposite to the object to be polished (claim 31 ). This reduces the amount of light reflected on the surface of the window for measuring the polishing state that passes through the window, and reduces the attenuation of the light intensity for measuring the polishing state. The film thickness measurement accuracy does not decrease.

Further, the semiconductor device manufacturing method according to the present invention has a step of flattening the surface of the semiconductor wafer using the flattening apparatus according to the present invention (claim 32 ).

According to the above semiconductor device manufacturing method, since the flattening apparatus according to the present invention is used in the step of flattening the surface of the semiconductor wafer, the polishing end point is detected in the step of flattening the surface of the semiconductor wafer. Since the accuracy or the measurement accuracy of the film thickness is not reduced, the yield in the step of flattening the surface of the semiconductor wafer is improved. As a result, it is possible to manufacture a semiconductor device at a lower cost than the conventional semiconductor device manufacturing method.

Furthermore, the semiconductor device according to the present invention is manufactured by the semiconductor device manufacturing method according to the present invention (claim 33 ).

Since the semiconductor device is manufactured by the semiconductor device manufacturing method according to the present invention,
The semiconductor device can be manufactured at a lower cost than the conventional semiconductor device manufacturing method, and the manufacturing cost of the semiconductor device can be reduced.

[0051]

BEST MODE FOR CARRYING OUT THE INVENTION A polishing body according to a first embodiment of the present invention and a flattening apparatus according to a second embodiment of the present invention will be described. 1 (a), (b), (c),
FIG. 3D is a diagram showing a polishing body according to the first embodiment of the present invention. 1 (a) is a top view, FIG. 1 (b) is a sectional view of the A-O portion of FIG. 1 (a), and FIG. 1 (c) is a B-O portion of FIG. 1 (a). FIG. 1D is a cross-sectional view, and FIG. 1D is a cross-sectional view of the C-O portion of FIG.

In the first embodiment, the polishing body 12 has three openings 13a, 13b, 13c. The window 11a is installed in the opening 13a, the window 11b is installed in the opening 13b, and the window 11c is installed in the opening 13c. Figure 1
In (b), (c), and (d), the upper surface of the polishing body 12 in the figure is the surface of the polishing body, and the upper surfaces of the windows 11a, 11b, 11c in the figure are the polishing object side of the window. Is the surface of.

The surface of each window 11a, 11b, 11c is recessed with respect to the surface of the polishing body 12, and the amount of each recess is different for each opening. As a result, the amount of depression for each opening changes stepwise. In the polishing body 12 according to the first embodiment, the window 11a of the opening 13a has the shortest and the window 11c of the opening 13c has the longest amount of depression of the surface of the window on the side of the polishing object with respect to the surface of the polishing body. The amount of depression of the window 11b of the opening 13b is approximately halfway between the amount of depression of the opening 13a and the amount of depression of the opening 13c.

FIG. 2 is a schematic configuration diagram of a flattening device according to a second embodiment of the present invention. The flattening apparatus according to the present invention includes a polishing member 31, a polishing object holding unit 32 (hereinafter referred to as a polishing head), and an abrasive supply unit 34. Then, a silicon wafer 33, which is an object to be polished, is attached to the polishing head 32, and an abrasive supply unit 34 supplies an abrasive (slurry) 35. The polishing member 31 has the polishing body 12 according to the first embodiment set on a surface plate 36 having an opening 38. The polishing body 12 is attached to the surface plate 36 with a double-sided tape or an adhesive. It is attached. An apparatus 39 for optically observing the polishing surface of the silicon wafer 33 to be polished through the opening 38 and measuring the polishing state is also installed. Although FIG. 2 shows only one opening,
The surface plate 36 of the flattening device according to the second embodiment is a polishing body.
It has three openings corresponding to the number of 12 openings. Further, in FIG. 2, the window installed in the polishing body 12 is omitted. The opening 38 formed in the surface plate 36 and the opening (not shown) formed in the polishing body 12 overlap each other. Although not shown, the other two openings of the platen 36 are also platen similarly.
The opening formed in 36 and the opening formed in the polishing body 12 overlap. Thus, by providing a transparent window in the opening of the polishing body 12, the light 17 emitted from the device 39 for measuring the polishing state and the light reflected on the polishing surface of the silicon wafer 33 pass through the window, Abrasive 35 is opening
It is possible to prevent leakage from 38 to below the surface plate 36.

The silicon wafer 33, which is the object to be polished, is held by the polishing head 32, swung while rotating, and pressed against the polishing body 12 of the polishing member 31 with a predetermined pressure. The polishing member 31 is also rotated so that relative movement with the silicon wafer 33 is performed. In this state, the polishing agent 35 is supplied from the polishing agent supply unit 34 onto the polishing body 12, and the polishing agent 35 is transferred to the polishing body 12.
It diffuses above and enters between the polishing body 12 and the silicon wafer 33 with the relative movement of the polishing member 31 and the silicon wafer 33, and polishes the polishing surface of the silicon wafer 33. That is, the mechanical polishing by the relative motion of the polishing member 31 and the silicon wafer 33 and the chemical action of the polishing agent 35 act synergistically to perform good polishing.

Immediately after the start of polishing, in the initial state, the portion of the opening 13a having the shortest amount of depression on the surface of the polishing object side of the window relative to the surface of the polishing body is used for observing the state of the polishing surface. As a result, of the light emitted from the polishing state measuring device 39, reflected by the polishing surface of the silicon wafer 33, and returning to the polishing state measuring device 39, the window 11a installed in the opening 13a is emitted. The state of the polished surface is observed by the light passing through.
A position detection sensor (not shown) is installed on the surface plate 36. When the surface plate 36 rotates and the specific position of the surface plate 36 reaches the position of the position detection sensor, the position detection sensor outputs a trigger signal. A device that measures the polishing state from the position of the surface plate 36 where the surface plate 36 rotates and the position detection sensor outputs a trigger signal.
The time interval for the opening 13a to reach the top of the 39 is 3
Determined by the number of rotations of 6. The time interval may be calculated or measured in advance, and the device 39 for observing the state of the polishing surface may be operated when the time interval has elapsed after the position detection sensor outputs the trigger signal. As a result, it is possible to always detect the polishing end point or measure the film thickness at the opening 13a.

The polishing body is dressed every time one silicon wafer is polished. A diamond grindstone or the like is used for dressing. After dressing
Next, the silicon wafer to be polished is attached to the polishing head 32, and polishing is performed. In this way, the polishing process and the dressing process are alternately repeated.

With each dressing, the surface of the polishing body 12 is shaved, and the recess amount of the window 11a of the opening 13a with respect to the surface of the polishing body 12 becomes shorter. When the recess amount becomes 0, the dressing target of the window 11a is dressed. The surface on the object side will be scratched. When the window becomes scratched, light scattering and the like at the window portion increase, and thus the accuracy of detection of the polishing end point and the accuracy of film thickness measurement decrease. For this reason, the opening 13 which has the second shortest dent amount in the initial state for detecting the polishing end point and measuring the film thickness.
Switch to do as in b. In order to switch the detection of the polishing end point and the film thickness measurement to the opening 13b, it is necessary to operate the device 39 for measuring the polishing state after the position detection sensor installed on the surface plate 36 outputs the trigger signal. The time interval may be changed to an appropriate time interval, and the device 39 for measuring the polishing state may be operated when the opening 13b comes on the device 39 for measuring the polishing state.

Then, by repeating the polishing step and the dressing step, the amount of depression of the surface of the opening 11b on the side of the object to be polished of the window 11b becomes 0, and the dressing scratches the surface of the window 11b on the side of the object to be polished. Then, the polishing end point is detected and the film thickness is measured at the opening 13c, which has the longest dent amount in the initial state. The detection of the polishing end point and the switching of the film thickness measurement from the openings 13b to 13c may be performed in the same manner as the above-described switching from the openings 13a to 13b. Thus, the surface on the side of the object to be polished of the window installed in the opening used for detecting the polishing end point and measuring the film thickness at the time of dressing is recessed with respect to the surface of the polishing body. The window is not scratched.

It should be noted that when the amount of light received by the device 39 for measuring the polishing state becomes smaller than a preset set value, a control device for switching to the next opening is provided to switch the opening. You can go.

In the first and second embodiments,
The surface plate 36 has three openings, and the polishing body 12 has three openings having windows, but the number of these openings may be two or four. One or more is acceptable. In that case, the observation of the polishing state can be switched a number of times corresponding to the number of these openings.

As described above, in the flattening apparatus according to the second embodiment in which the polishing body according to the first embodiment is installed, a plurality of windows having different recesses for each opening are installed in the polishing body 12. Therefore, even if the window is scratched and optically opaque due to dressing, the window used for detecting the polishing end point and measuring the film thickness can be switched to another opening window to detect the polishing end point and measure the film thickness. It will be possible. As a result, the same polishing body can be used for polishing for a long time as compared with the conventional one, and the frequency of exchanging the polishing body or the window is reduced, so that the cost for polishing can be reduced.

Next, a polishing body according to the third embodiment of the present invention and a flattening apparatus according to the fourth embodiment of the present invention will be described. 3A and 3B show the third embodiment of the present invention.
It is a figure which shows the grinding | polishing body by embodiment of this. Figure 3 (a)
Is a top view, and FIG. 3B is a cross-sectional view of a portion D-E in FIG.

The polishing body 22 according to the third embodiment has one opening. Windows installed in that opening
21 has a step-like cross section and has three recesses 21 in the surface of the window 21 on the side of the object to be polished with respect to the surface of the polishing body.
Different for a, 21b, and 21c. The amount of depression of the surface of the window on the side of the object to be polished with respect to the surface of the polishing body is shortest at 21a, longest at 21c, and 21b at 21a and 2a.
The length is almost in the middle of the 1c part. This allows
The amount of depression of the surface of the window 21 on the side of the object to be polished changes stepwise.

When a polymer resin is used for the material of the window 21, the window 21 having a stepped step on the surface is prepared by pouring a resin in a molten state into a stepped mold and curing it.

The flattening apparatus according to the fourth embodiment is the same as the flattening apparatus according to the second embodiment (FIG. 2).
Instead of the abrasive body (12 in FIG. 2) according to the embodiment of FIG.
The polishing body 22 according to the embodiment is installed. However, since the polishing body 22 according to the third embodiment has only one opening, only one opening is formed on the surface plate 36 of the flattening device according to the fourth embodiment. Is. The opening formed on the surface plate 36 is a polishing body.
It overlaps with the opening formed in 22. The description of the same parts as those of the flattening apparatus according to the second embodiment will be omitted.

Immediately after the start of polishing, the amount of depression of the surface of the window 21 on the side of the object to be polished with respect to the surface of the polishing body is shortest in the initial state.
The portion 21a is used to observe the state of the polished surface. As a result, of the light emitted from the polishing state measuring device 39, reflected by the polishing surface of the silicon wafer 33, and returning to the polishing state measuring device 39, the light passing through the portion 21a of the window 21 is used. The condition of the polished surface is observed. A position detection sensor (not shown) is installed on the surface plate 36 as in the flattening apparatus according to the second embodiment. The surface plate 36 rotates and the position detection sensor outputs a trigger signal from the position of the surface plate 36 to reach the portion 21a of the window 21 installed in the opening on the device 39 for measuring the polishing state. The time interval up to is 36
It is determined by the number of rotations of. Therefore, similar to the second embodiment, a device for preliminarily calculating or measuring the time interval and observing the state of the polishing surface after the time interval has elapsed after the position detection sensor outputs the trigger signal.
You can operate 39.

Then, similarly to the second embodiment, the polishing step and the dressing step are repeated.

The surface of the polishing body 22 is scraped each time dressing is performed, and 21 a of the windows 21 of the opening with respect to the surface of the polishing body 22 is removed.
The amount of dents in the area is shortened, and when the amount of dent becomes 0, the 21a part of the window 21 is damaged by the dressing. When the portion 21a of the window 21 becomes scratched, the scattering of light and the like at the portion 21a increases, so that the accuracy of detection of the polishing end point and the accuracy of film thickness measurement decrease. Therefore, the polishing end point detection and the film thickness measurement are switched to be performed in the portion 21b of the window 21 in which the recess amount is second shortest in the initial state. Window 21 for detection of polishing end point and film thickness measurement
To switch to do in part 21b of
Change the time interval from the position detection sensor installed in 6 outputs the trigger signal to the operation of the device 39 for measuring the polishing state to an appropriate time interval, and place it on the device 39 for measuring the polishing state. The device 39 for measuring the polishing state may be operated when the portion 21b of the window 21 comes.

Then, by repeating the polishing process and the dressing process, the amount of depression of the portion 21b of the window 21 becomes zero, and when the portion 21b of the window 21 is scratched by the dressing, it is next time. 21c out of the windows 21 with the longest dent amount in the initial state when detecting the polishing end point and measuring the film thickness.
Switch to the part. As described above, when dressing, the surface on the side of the object to be polished of the window part installed in the opening used for detecting the polishing end point and measuring the film thickness is dented with respect to the surface of the polishing body. Sometimes the part does not get scratched.

In the third and fourth embodiments,
The polishing body 22 has a stepwise window having three steps on the surface of the opening, but the number of steps may be two steps or four steps or more. In that case, the observation of the polishing state can be switched as many times as the number of steps.

As described above, in the flattening apparatus according to the fourth embodiment using the polishing body according to the third embodiment,
Since the polishing body is provided with a window having a stepped surface, even if a part of the window is damaged by dressing and becomes optically opaque, the window part to be observed by the device 39 for measuring the polishing state is switched. This makes it possible to detect the polishing end point and measure the film thickness. As a result, the same polishing body can be used for polishing for a long time as compared with the conventional one, and the frequency of exchanging the polishing body or the window is reduced, so that the cost for polishing can be reduced.

Next, a polishing body according to the fifth embodiment of the present invention and a flattening apparatus according to the sixth embodiment of the present invention will be described. 4 (a) and 4 (b) show the fifth embodiment of the present invention.
It is a figure which shows the grinding | polishing body by embodiment of this. Figure 4 (a)
4B is a top view, and FIG. 4B is a cross-sectional view of the F-G portion of FIG. 4A.

The polishing body 42 according to the fifth embodiment has one opening. The parallel-plate windows 41 installed in the openings are arranged so that their cross sections are oblique, and the amount of depression from the surface of the polishing body differs in the FG direction of FIG. 4 (a). . As a result, the amount of depression of the surface of the window 41 on the side of the object to be polished is continuously changing. When the four points 41a, 41b, 41c, 41d on the surface of the window 41 are designated, the amount of depression of the surface of the window on the side of the polishing object relative to the surface of the polishing body is shortest at 41a and second at 41b. Short, 41c is the third shortest, and 41d is the longest.

The flattening apparatus according to the sixth embodiment is the same as the flattening apparatus according to the second embodiment (FIG. 2).
5 in place of the abrasive body (12 in FIG. 2) according to the embodiment of
The polishing body 42 according to the embodiment is installed. However, since the polishing body 42 according to the fifth embodiment has only one opening, only one opening is formed on the surface plate 36 of the flattening device according to the sixth embodiment. Is. The opening of the surface plate 36 overlaps with the opening of the polishing body 42. The description of the same parts as those of the flattening apparatus according to the second embodiment will be omitted.

Immediately after the start of polishing, the amount of depression of the surface of the window 41 on the side of the object to be polished with respect to the surface of the polishing body is the shortest in the initial state.
The portion 41a is used to observe the state of the polished surface. As a result, of the light emitted from the polishing state measuring device 39, reflected by the polishing surface of the silicon wafer 33, and returning to the polishing state measuring device 39, the light passing through the portion 41a of the window 41 is used. The condition of the polished surface is observed. A position detection sensor (not shown) is installed on the surface plate 36 as in the flattening apparatus according to the second embodiment. The surface plate 36 rotates and the position detection sensor outputs a trigger signal from the position of the surface plate 36 to reach the portion 41a of the window 41 installed in the opening on the device 39 for measuring the polishing state. The time interval up to is 36
It is determined by the number of rotations of. Therefore, as in the second embodiment, a device for preliminarily calculating or measuring the time interval and observing the state of the polishing surface after the time has elapsed after the position detection sensor outputs the trigger signal. 39
Should be operated.

Then, the polishing step and the dressing step are repeated as in the second embodiment.

The surface of the polishing body 42 is scraped each time dressing is performed, and 41 a of the window 41 of the opening with respect to the surface of the polishing body 42 is removed.
The amount of dents in the area is shortened, and when the amount of dents becomes 0, the dressing causes damage to the part 41a of the window 41. When the portion 41a of the window 41 becomes scratched, the scattering of light and the like at the portion 41a increases, so that the precision of detection of the polishing end point and the precision of film thickness measurement decrease. Therefore, the polishing end point detection and the film thickness measurement are switched to be performed at the portion 41b of the window 41 having the second shortest dent amount. 41 out of 41 windows for detecting polishing end point and film thickness measurement
In order to switch to the part b, the time interval from the position detection sensor installed on the surface plate 36 outputting the trigger signal to the operation of the device 39 for measuring the polishing state is set to an appropriate time interval. Device for changing and measuring the polishing condition 39
The device 39 for measuring the polishing state may be operated when the portion 41b of the window 41 comes to the top.

Then, by repeating the polishing step and the dressing step, the amount of depression of the portion 41b of the window 41 becomes 0, and when the portion of the window 41b of the window 41 is scratched by the dressing, it is next time. Switches the detection of the polishing end point and the film thickness measurement to the portion 41c of the window 41 having the third shortest dent amount. Further, by repeating the polishing step and the dressing step, the dent amount of the portion 41c of the window 41 becomes 0, and if the portion 41c of the window 41 is scratched by the dressing, the polishing end point is finished. Detection and film thickness measurement are switched to the portion 41d of the window 41 having the longest dent amount. As described above, when dressing, the surface on the side of the object to be polished of the window part installed in the opening used for detecting the polishing end point and measuring the film thickness is dented with respect to the surface of the polishing body. Sometimes the part does not get scratched.

Further, in the fifth and sixth embodiments, switching is performed at four locations on the window, but the switching may be performed at two locations, three locations, or more than four locations. In that case, observation of the polishing state can be switched a number of times corresponding to the number of these measured portions.

As described above, in the flattening apparatus according to the sixth embodiment using the polishing body according to the fifth embodiment,
Since the parallel plate-shaped window is installed on the polishing body so that its surface is inclined, even if a part of the window is damaged by dressing and becomes optically opaque, the window to be observed by the device 39 for measuring the polishing state is By switching the portions, the polishing end point can be detected and the film thickness can be measured. As a result, the same polishing body can be used for polishing for a long time as compared with the conventional one, and the frequency of exchanging the polishing body or the window is reduced, so that the cost for polishing can be reduced.

In the flattening apparatus according to the fourth and sixth embodiments described above, as in the second embodiment, the amount of light received by the apparatus 39 for measuring the polishing state is greater than the preset value. When the size of the window 21 becomes smaller, a control device for switching to the next opening is provided so that the parts 21a, 21b of the window 21 are
21c may be switched and portions 41a, 41b, 41c, 41d of the window 41 may be switched.

Further, in the above-described first to sixth embodiments, when the recessed amount of the surface of the window on the side of the object to be polished with respect to the surface of the polishing body exceeds 400 μm, the amount of the polishing agent accumulated in the recessed portion is Will increase. Then, the polishing agent serves as a scatterer and attenuates the light 17 emitted from the device 39 for measuring the polishing state, so that the accuracy of detection of the polishing end point and the accuracy of film thickness measurement decrease. Therefore, the dent amount d of the portion of the window through which the light from the device 39 for measuring the polishing state passes (the portion used for detecting the polishing end point and measuring the film thickness) is 0 μm <d ≦ 400 μm.
Is preferred.

Next, a polishing body according to the seventh embodiment of the present invention and a flattening apparatus according to the eighth embodiment of the present invention will be described. 5 (a) and 5 (b) show the seventh embodiment of the present invention.
It is a figure which shows the grinding | polishing body by embodiment of this. Figure 5 (a)
Is a top view, and FIG. 5B is a cross-sectional view of the HI portion of FIG.

The polishing body 52 according to the seventh embodiment has one opening. The parallel flat plate-shaped window 51 installed in the opening is made of four transparent materials 51a, 51b, 51c and 51d.
Has a structure in which they are laminated with an adhesive force such that they can be peeled off. The transparent materials 51a, 51b, 51c, 51d are adhered by an adhesive or a double-sided tape having an adhesive force that is peelable. By peeling the transparent materials 51a, 51b, 51c, and 51d one by one from the top, the amount of depression of the window 52 with respect to the surface of the polishing body 52 on the side of the object to be polished is changed stepwise.

The flattening apparatus according to the eighth embodiment is the same as the flattening apparatus according to the second embodiment (FIG. 2).
7 in place of the polishing body (12 in FIG. 2) according to the embodiment of
The polishing body 52 according to the embodiment is installed. However, since the polishing body according to the seventh embodiment has only one opening, only one opening is formed on the surface plate 36 of the flattening device according to the eighth embodiment. is there.
The opening of the surface plate 36 overlaps the opening of the polishing body. The description of the same parts as those of the flattening apparatus according to the second embodiment will be omitted.

Immediately after the start of polishing, a window in which four transparent materials 51a, 51b, 51c and 51d are laminated in the initial state is used for observing the state of the polished surface. As a result, 4 out of the light emitted from the polishing state measuring device 39, reflected by the polishing surface of the silicon wafer 33 and returned to the polishing state measuring device 39.
The state of the polished surface is observed by the light passing through the window in which the transparent materials 51a, 51b, 51c, 51d are laminated. Using the openings formed in the surface plate 36 and the polishing body 52 as the surface plate 36 rotates, a mechanism for detecting the polishing end point and measuring the film thickness,
The method is the same as that of the second embodiment, so the explanation is omitted.

Then, the polishing step and the dressing step are repeated as in the second embodiment.

With each dressing, the surface of the polishing body is shaved, and the amount of depression of the surface of the transparent material 51a in the window 51 of the opening with respect to the surface of the polishing body 52 on the side of the object to be polished becomes shorter. When becomes 0, transparent material 51 is applied by dressing.
The surface of a becomes scratched. When the surface of the transparent material 51a of the window 51 becomes scratched, the transparent material 51a
Since the light scattering and the like at the point of time increase, the accuracy of end point detection and the accuracy of film thickness measurement decrease. For this reason, the stacked windows 51
Then, the transparent material 51a is peeled off so that the transparent material 51b becomes the uppermost surface of the window to detect the polishing end point and measure the film thickness. As a result, the surface of the window 51 is recessed from the surface of the polishing body 52, and the surface of the window 51 is not scratched, and the polishing end point can be normally detected or the film thickness can be measured. In the flattening apparatus according to the eighth embodiment, the same position of the window 51 having the same opening can be used for detecting the polishing end point or measuring the film thickness. Therefore, unlike the flattening apparatus according to the second embodiment, It is not necessary to switch the position of the window used for detecting the polishing end point and measuring the film thickness.

Then, by repeating the polishing step and the dressing step, the amount of depression of the surface of the transparent material 51b of the window 51 on the side of the object to be polished becomes 0, and the transparent material 51b is scratched by the dressing. This time, the transparent material 51b is peeled from the window 51 so that the transparent material 51c is the uppermost surface of the window to detect the polishing end point and measure the film thickness. Further, by repeating the polishing step and the dressing step, the amount of depression of the surface of the transparent material 51c of the window 51 on the side of the object to be polished becomes 0, and when the dressing comes to scratch the transparent material 51c portion, next time, Transparent material through window 51
The portion 51c is peeled off, and the transparent material 51d is placed on the uppermost surface of the window 51 to detect the polishing end point and measure the film thickness. As described above, when dressing, the surface on the side of the object to be polished of the window part installed in the opening used for detecting the polishing end point and measuring the film thickness is dented with respect to the surface of the polishing body. Sometimes the part does not get scratched.

In order to know the timing of peeling the window portions 51a, 51b, 51c, peeling is performed when the amount of light received by the device 39 for measuring the polishing state becomes smaller than a preset value. A control device may be provided to output a signal notifying the timing to perform.

The window 51 has four transparent materials 51a, 51b,
Although the window in which 51c and 51d are laminated is used, a window in which two, three, or five or more transparent materials are laminated may be used. In that case, the observation of the polishing state can be switched as many times as the number of these transparent materials.

Further, when the concave amount of the surface of the window 51 on the side of the object to be polished with respect to the surface of the polishing body 52 exceeds 400 μm, the amount of the polishing agent accumulated in the recessed portion increases, and the polishing agent becomes a scatterer and the polishing state Since the light 17 emitted from the device 39 for measuring the above is attenuated, the accuracy of detection of the polishing end point and the accuracy of film thickness measurement are deteriorated. For this reason, the recess amount d of the portion through which the light from the device 39 for measuring the polishing state of the window 51 passes (the portion used for detecting the polishing end point and measuring the film thickness) is 0 μm <d ≦ 400.
It is preferably μm. Accordingly, the thickness t1 of each of the transparent materials 51a, 51b, and 51c excluding the transparent material 51d at the lowermost portion is preferably 0 μm <t1 ≦ 400 μm.

As described above, in the flattening apparatus according to the eighth embodiment using the polishing body according to the seventh embodiment,
Since a window in which a transparent material is laminated on the polishing body is provided, even if the surface of the window on the side of the object to be polished is damaged by dressing and becomes optically opaque, the transparent material of the uppermost layer of the laminated window is removed. By peeling, the polishing end point can be detected and the film thickness can be measured. As a result, the same polishing body can be used for polishing for a long time as compared with the conventional one, and the frequency of exchanging the polishing body or the window is reduced, so that the cost for polishing can be reduced.

In the above-described first to eighth embodiments, the window is installed directly in the opening of the polishing body, but the window may not be installed directly in the polishing body. For example, the window may be installed on the surface plate directly or through a jig so as to close at least a part of the opening of the polishing body.

Further, in the first to eighth embodiments, the openings 13a, 13b, 13c provided in the polishing body 12 and the polishing body 2 are provided.
The shapes of the openings provided in 2, the openings provided in the polishing body 32, the openings provided in the polishing body 42, and the openings provided in the polishing body 52 are stepwise. However, these openings may be linear through holes.

Further, in the first to eighth embodiments, the window
11a, 11b, 11c, 21, 41, 51, glass, acrylic,
Transparent materials such as polyurethane, epoxy, PET, vinyl chloride, polycarbonate, polyester, or silicone rubber are used. The polishing characteristics such as polishing rate and hardness of these transparent materials are preferably the same as the polishing characteristics of the polishing body. As a result, even when the window comes into contact with the silicon wafer that is the object to be polished, there is an effect that the polishing surface of the silicon wafer is not scratched by the window and the polishing is not uneven.

Next explained is a flattening apparatus according to the ninth embodiment of the invention. The flattening apparatus according to the ninth embodiment is a modification of the flattening apparatus according to the second embodiment, and description of the same parts as those of the flattening apparatus according to the second embodiment will be omitted. The flattening apparatus according to the ninth embodiment has one surface plate used for detecting the polishing end point and measuring the film thickness, and one opening formed in the polishing body. And the openings formed in the polishing body overlap.

FIG. 6 is a sectional view showing the vicinity of the opening 66 of the surface plate 36 of the flattening apparatus according to the ninth embodiment of the present invention. A window support 62 for supporting a window 63 is attached to the moving device 61, and a movable window in which the window 63 is installed at the upper end of the window support 62 is an opening of the surface plate 36.
It is located at 66. Thus, the window 63 is installed on the surface plate 36 via the window support 62 and the moving device 61. An electric stage, a piezo stage, or the like is used as the moving device 61. The window support 62 has a pipe shape, and the hollow portion of the pipe serves as an optical path for detecting the polishing end point, measuring the film thickness, and the like. Opening of surface plate 36 to prevent the infiltration of abrasives
The gap between 66 and the window support 62 is grease (not shown) and / or
Or it is sealed with an O-ring 64. By moving the window support 62 and the window 63 in the vertical direction in FIG. 6 by the moving device 61, the position of the surface of the window 63 on the side of the polishing object is moved.

Below the surface plate 36, a device 39 for observing the state of the polishing surface and a device 68 for detecting the distance between the surface of the window 63 and the polishing surface of the silicon wafer to be polished are arranged. The distance between the surface of the window 63 on the object to be polished and the polishing surface of the object to be polished is the same as the amount of depression of the surface of the window 63 on the object to be polished side with respect to the surface of the polishing body 69. The device 39 for observing the state of the polished surface detects the polishing end point and measures the film thickness. As the device 68 for detecting the interval, a sensor using the principle of autofocus, a sensor using the principle of interference, or a signal for irradiating light and receiving reflected light to control the amount of light received to be constant A sensor or the like that outputs is used. From the measurement result of the device 68 that detects the interval, the computer PC that is the control device, the stage controller Cnot.
The motor M of the electric stage is driven via the to control the distance between the surface of the window 63 on the side of the polishing object and the polishing surface of the silicon wafer (not shown) which is the polishing object. Then, the control of the gap between the surface of the window 63 and the polishing surface of the silicon wafer (not shown) by the signal from the gap detecting device 68 is set by the computer PC so that the gap is always constant. .

Similar to the second embodiment, dressing is performed each time one silicon wafer is polished.
Even during dressing, the position of the surface of the window 63 is controlled so as to be fixed at the position controlled during the above-described polishing.
After the dressing, the silicon wafer to be polished next is attached to the polishing head 32 and polishing is performed. In this way, the polishing process and the dressing process are alternately repeated.

The position of the window 63 is controlled by using the device 68 for detecting the distance between the surface of the window 63 on the side of the object to be polished and the polishing surface of the silicon wafer which is the object to be polished. Instead of the detecting device 68, a device for detecting the wear state of the polishing body 69 may be installed. In that case, the moving device 61 may be controlled so as to move the surface of the window 63 on the side of the object to be polished in the downward direction in FIG. 6 by the amount of wear of the polishing body 69. As a device for detecting the wear state of the polishing body, a stylus type displacement gauge, an optical displacement gauge, or the like is used. Further, the position of the window 63 may be controlled by using both the device 68 for detecting the interval and the device for detecting the abrasion state of the polishing body.

As described above, in the flattening apparatus according to the ninth embodiment, since the position of the surface of the window on the side of the object to be polished is controlled by the moving device, the window and the silicon wafer which is the object to be polished are polished. The surface on the side of the object to be polished of the window is recessed with respect to the surface of the polishing body so as to have a constant distance between the surface and the surface, and this state is maintained during dressing. Since the surface on the side of the object to be polished is not damaged, it is possible to always detect the polishing end point and measure the film thickness. As a result, the same polishing body can be used for polishing for a long time as compared with the conventional one, and the frequency of exchanging the polishing body or the window is reduced, so that the cost for polishing can be reduced.

Further, in the flattening apparatus according to the ninth embodiment, the control of the distance between the surface of the window 63 and the polishing surface of the silicon wafer is performed by setting the computer PC so that the distance is always constant. However, unlike this control method, a computer PC is used to predict the wear amount of the polishing object from the polishing conditions, polishing time, dressing conditions, and dressing time, and the gap between the window surface and the silicon wafer polishing surface is estimated. May be controlled.

In the above-mentioned first to ninth embodiments, 1
Although it is described that the polishing body is dressed every time the polishing of one silicon wafer is completed, the polishing body may be dressed every time the polishing of an appropriate number of two or more silicon wafers is completed.

Next explained is a flattening apparatus according to the tenth embodiment of the invention. The structure of the flattening apparatus according to the tenth embodiment of the present invention is the same as that of the flattening apparatus according to the ninth embodiment. In the flattening apparatus according to the tenth embodiment, a position sensor is further installed on the surface plate 36, and as the position sensor, only when the silicon wafer is above the opening 66 of the surface plate (or the silicon wafer is A computer that outputs the signal from the position sensor using a device that outputs a signal only when it is not above the opening of the surface plate).
Import to PC. The window 63 for the surface of the window 63 when the silicon wafer is located above the opening 66 and the gap between the silicon wafer and the surface of the polishing body 69 when the silicon wafer is located at any other position. Dynamic control is performed in synchronism with the rotation of the surface plate 36 so that the window 63 is moved so that the amount of depression on the surface of the object to be polished becomes longer.

As described above, the amount of depression of the window is controlled to be short only when the polishing end point or the film thickness is measured during polishing, and the amount of depression is lengthened otherwise. It is not necessary to perform dressing between polishing, and a diamond grinding stone for dressing is installed together with the polishing head on the polishing body to perform dressing at the same time as polishing (in-situ (in-situ) Dressing) is possible.

As described above, in the flattening device according to the tenth embodiment, the position of the surface of the window on the side of the object to be polished is controlled by the moving device, so that the diamond grindstone for dressing forms the opening of the polishing body. When passing through the top of the window, the depth of the recess on the surface of the polishing object side of the window relative to the surface of the polishing object is long, so even if dressing is performed while polishing the polishing object, the window is polished by dressing. It is possible to always detect the polishing end point and measure the film thickness without damaging the surface of the object side. As a result, the same polishing body can be used for polishing for a longer period of time than before, the frequency of polishing body or window replacement is reduced, and there is no need to take time to perform dressing, so polishing of multiple polishing objects is possible. Since the total time required for polishing is shortened, there is an effect that the cost required for polishing can be reduced.

In the ninth and tenth embodiments described above, when the recessed amount of the surface of the window on the side of the object to be polished with respect to the surface of the polishing body exceeds 400 μm, the amount of the polishing agent accumulated in the recessed portion increases. . Then, the polishing agent serves as a scatterer and attenuates the light 17 emitted from the device 39 for measuring the polishing state, so that the accuracy of detection of the polishing end point and the accuracy of film thickness measurement decrease. For this reason, it is preferable that the position of the window is controlled so that the amount of depression d of the window when the light from the device 39 for measuring the polishing state passes is 0 μm <d ≦ 400 μm.

In the ninth and tenth embodiments, the window 63 is made of a transparent material such as glass, acrylic, polyurethane, epoxy, PET, vinyl chloride, polycarbonate, polyester, or silicone rubber.

Further, in the first to tenth embodiments, when the thickness of the window is less than 10% of the thickness of the polishing body, the thickness of the window becomes thin so that the window may be deformed. When the window is deformed and optically distorted, the distortion causes the window to have a function as a lens or the like, so that there is a problem that detection of the polishing end point and measurement of the film thickness become unstable. Therefore, the depth of the recess is 90% or less of the thickness of the polishing body so that the thickness of the thinnest portion of the window is 10% or more of the thickness of the polishing body. Preferably there is. As a result, there is an effect that instability in detection of the polishing end point and instability in film thickness measurement due to the deformation of the window do not occur.

Next explained is a flattening apparatus according to the eleventh embodiment of the invention. The flattening apparatus according to the eleventh embodiment is a modification of the flattening apparatus according to the second embodiment, and description of the same parts as those of the flattening apparatus according to the second embodiment will be omitted. The flattening apparatus according to the eleventh embodiment has a surface plate used for detecting a polishing end point and a film thickness measurement, and an opening formed in the polishing body. And the openings formed in the polishing body overlap.

FIG. 7A is a sectional view of the vicinity of the opening of the flattening apparatus according to the eleventh embodiment of the present invention.
FIG. 16B is a sectional view showing a state near the opening of the flattening apparatus according to the eleventh embodiment of the present invention when the polishing object comes over the opening. A transparent rubber window 72 is attached to the upper end of the window fixing cylinder 71, and a glass window 73 is attached to the lower end. Further, an air pressure control device 74 is connected to the window fixing cylinder 71 to pressurize / depressurize the inside of the window fixing cylinder 71. A polishing plate 75 with an opening to match the size of the transparent rubber window 72 is a surface plate.
It is installed by being attached to 36. When the pressure inside the window fixing cylinder 71 is reduced (normal pressure), the surface of the transparent rubber window 72 on the side of the object to be polished is dented with respect to the surface of the polishing body 75.
The window fixing cylinder 71 is installed in the opening 77 of the surface plate 36. When the air pressure control device 74 pressurizes the pressure in the window fixing barrel 71, the transparent rubber window 72 attached to the upper end of the window fixing barrel 71 bulges upward. When the transparent rubber window 72 bulges upward, the window 72 slightly pops up from the surface of the polishing body 75, but when the silicon wafer 33 is above the opening 77, as shown in FIG. The surface of the transparent rubber window 72 on the side of the object to be polished is in close contact with the polishing surface of the silicon wafer 33.
As described above, the pneumatic control device 74 and the window fixing barrel 71 adjust the pressure inside the window fixing barrel 71 to allow the transparent rubber window 72 to move.
To function as a moving device for moving the surface of the transparent rubber window 72 on the side of the object to be polished in the vertical direction in FIG. Therefore, the transparent rubber window 72 is installed on the surface plate 36 via the window fixing cylinder 71 having a function as a moving device.

A position sensor is installed on the surface plate 36, and a silicon wafer is used as the position sensor for the opening 77 of the surface plate.
Use a device that outputs a signal only when it is above (or only when the silicon wafer is not above the opening of the surface plate),
The signal from the position sensor is captured by a computer PC. When the silicon wafer is located above the opening 77, the pressure inside the window fixing cylinder 71 is increased, and when it is at any other position, the pressure inside the window fixing cylinder 71 is reduced (normal pressure). Therefore, the dynamic control is performed in synchronization with the rotation of the surface plate 36.
By such control, when the silicon wafer is located above the opening 77, the surface of the transparent rubber window 72 on the side of the object to be polished is in contact with the surface of the silicon wafer 33 and is located at other positions. At this time, the surface of the transparent rubber window 72 on the side of the object to be polished becomes recessed with respect to the surface of the polishing body 75.

A device 39 for observing the state of the polishing surface is arranged under the surface plate 36, and the detection of the polishing end point and the film thickness measurement are performed in the same manner as in the ninth embodiment.

By controlling the position of the surface of the window 72 as described above, it is possible to perform in-situ (in-situ) dressing without having to perform dressing of the polishing body 75 between polishing.

The surface of the transparent rubber window 72 on the side of the object to be polished comes into contact with the silicon wafer 33 when the polishing end point is detected or the film thickness is measured. The object-side surface may not be in contact with the silicon wafer 33. In that case, when the amount of depression of the surface of the transparent rubber window 72 on the side of the object to be polished with respect to the surface of the polishing body 75 exceeds 400 μm, the amount of the polishing agent accumulated in the depressed portion increases. Then, the polishing agent serves as a scatterer and attenuates the light 17 emitted from the device 39 for measuring the polishing state, so that the accuracy of detection of the polishing end point and the accuracy of film thickness measurement decrease. For this reason, the amount of depression d of the portion through which light from the device 39 for measuring the polishing state of the transparent rubber window 72 (the portion used for detecting the polishing end point and measuring the film thickness) is 0 μm <d ≦ 400 μm. It is preferable.

As described above, in the flattening apparatus according to the eleventh embodiment, the pressure in the window fixing cylinder 71 is controlled to control the position of the surface of the window on the side of the object to be polished. When the diamond grindstone passes over the opening of the polishing body, the amount of depression of the surface of the window on the side of the polishing target with respect to the surface of the polishing body becomes long. Therefore, even if dressing is performed while polishing the object to be polished, the surface of the window on the object side to be polished is not damaged by the dressing, and the polishing end point can be detected and the film thickness can be constantly measured. As a result, the same abrasive body can be
Can be used for polishing, the frequency of exchanging the polishing body or window is reduced, and since it is not necessary to take time to perform dressing, the total time required to polish a large number of objects to be polished can be shortened. There is an effect that it can be reduced.

In the above-mentioned first to eleventh embodiments, the device 39 for observing the state of the polishing surface installed under the surface plate 36 has a reflection spectral characteristic (reflection spectral spectrum).
Therefore, it is preferable to use an apparatus for detecting the polishing end point and measuring the film thickness. The reflection spectral spectrum measured by the device 39 for observing the state of the polished surface is compared with a reference spectrum obtained by simulation or the like in a computer (not shown) to calculate the film thickness or detect the polishing end point. As the device 39 for observing the state of the polishing surface,
Instead of the above-mentioned device for detecting the polishing end point and measuring the film thickness from the reflection spectral characteristic (reflection spectral spectrum), a device for detecting the polishing end point or measuring the film thickness from the change in reflectance at a specific wavelength, or the polishing surface It is also possible to use a device or the like for detecting the polishing end point or measuring the film thickness by image-processing the photographed image with a CCD camera or the like.

In the first to eleventh embodiments, it is preferable that the windows 11a, 11b, 11c, 21, 41, 51, 63, 72 and 77 have a transmittance of 22% or more. As a result, the attenuation of the light intensity for measuring the polishing state passing through the window is reduced, so that the accuracy of detecting the polishing end point and the accuracy of measuring the film thickness are not reduced.

Further, in the first to eleventh embodiments, an antireflection film is formed on the surface of the windows 11a, 11b, 11c, 21, 41, 51, 63, 72, 77 opposite to the object to be polished. Preferably. As a result, the amount of light for measuring the polishing state that passes through the window is reduced on the surface of the window on the opposite side of the object to be polished, and the attenuation of the light intensity for measuring the polishing state is reduced. Therefore, there is an effect that the detection accuracy of the polishing end point and the measurement accuracy of the film thickness do not decrease.

In the first to eleventh embodiments, the intensity of the light 17 emitted from the device 39 for measuring the polishing state and the intensity of the light 17 emitted from the device 39 for measuring the polishing state are passed through the window and the window and the silicon. A device that passes the polishing agent 35 between the wafers 33, reflects on the polishing surface of the silicon wafer 33, passes through the polishing agent 35 between the window and the silicon wafer 33 again, passes through the window again, and measures the polishing state. Regarding the relationship of the intensity of the light returning to 39, the ratio of the intensity of the light returning to the device to the intensity of the light 17 emitted from the device 39 for measuring the polishing state is preferably 5% or more. As a result, the intensity of the light returning to the apparatus for measuring the polishing state does not decrease, so that the accuracy of detecting the polishing end point and the accuracy of measuring the film thickness by the apparatus for measuring the polishing state do not decrease.

In the first to eleventh embodiments, dressing of the polishing body is performed. However, when a non-foaming material is used for the polishing body, dressing may not be necessary. Even with such a dressing-free polishing body, the surface of the polishing body is scraped as the object to be polished is polished. Therefore, even when the dressing-free polishing body is used in the first to eleventh embodiments, the window or the polishing body is not used. There is an effect that the frequency of exchanging is reduced and the cost required for polishing can be reduced.

FIG. 8 is a flow chart showing the semiconductor device manufacturing process. When the semiconductor device manufacturing process is started, first in step S200, an appropriate processing step is selected from the following steps S201 to S204. Depending on the selection, proceed to any of steps S201 to S204.

Step S201 is an oxidation step of oxidizing the surface of the silicon wafer. Step S202 is a CVD process for forming an insulating film on the surface of a silicon wafer by CVD or the like. Step S203 is an electrode forming step of forming electrodes on the silicon wafer by a process such as vapor deposition. Step S204 is an ion implantation step of implanting ions into the silicon wafer.

After the CVD process or the electrode forming process, the process proceeds to step S205. Step S205 is a CMP process. CMP
In the process, the flattening apparatus according to the present invention flattens the interlayer insulating film and forms a damascene by polishing the metal film on the surface of the semiconductor device.

After the CMP step or the oxidation step, step S
Continue to 206. Step S206 is a photolithography process. In the photolithography process, a resist is applied to a silicon wafer, a circuit pattern is printed on the silicon wafer by exposure using an exposure device, and the exposed silicon wafer is developed. Further, the next step S207 is an etching step in which a portion other than the developed resist image is shaved by etching, and then resist stripping is performed to remove the unnecessary resist after etching.

Next, in step S208, it is determined whether or not all necessary steps are completed. If not completed, the process returns to step S200, and the previous step is repeated to form a circuit pattern on the silicon wafer. If it is determined in step S208 that all the processes are completed, the process ends.

In the semiconductor device manufacturing method according to the present invention, since the flattening apparatus according to the present invention is used in the CMP step, the accuracy of detecting the polishing end point or the accuracy of measuring the film thickness in the CMP step is improved. The yield in the CMP process is improved. As a result, there is an effect that the semiconductor device can be manufactured at a lower cost than the conventional semiconductor device manufacturing method.

The flattening apparatus according to the present invention may be used in the CMP process of the semiconductor device manufacturing process other than the above semiconductor device manufacturing process.

The semiconductor device according to the present invention is manufactured by the semiconductor device manufacturing method according to the present invention. As a result, the semiconductor device can be manufactured at a lower cost than the conventional semiconductor device manufacturing method, and the manufacturing cost of the semiconductor device can be reduced.

[0132]

EXAMPLES Examples of the present invention will be described below.

Example 1 As the polishing body 12 (FIG. 1) according to the first embodiment, the layer under the polishing body is SUBA40 manufactured by Rodel.
A two-layer polishing body (hereinafter, referred to as IC1000 / SUBA400) in which the upper layer was IC1000 manufactured by Rodel was used.

The recess amount from the surface of the polishing body to the surface of the window on the side of the object to be polished is 0.15 mm at the opening 13a and at the opening 13b.
The windows 11a, 11b, and 11c made of polyurethane were arranged so that the width was 0.3 mm and the opening 13c was 0.45 mm.

After that, the above-mentioned polishing body was set on the surface plate of the flattening apparatus (FIG. 2) according to the second embodiment. Thermal oxide film
Polishing a 6-inch silicon wafer having a thickness of 1 μm is performed under the following conditions, and the residual film thickness of the silicon wafer is measured in-sit by the device 39 that measures the polishing state using the window 11a of the opening 13a.
u measured.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min.

The average polishing rate at this time was 430 nm / min. After polishing, use a diamond whetstone with an abrasive grain size of # 100
Dressing was performed for 1 minute.

A new 6-nm thick thermal oxide film was formed every time.
The above polishing and dressing steps were repeated using an inch silicon wafer. FIG. 9 is a graph of the reflection spectrum from the surface of the silicon wafer measured in-situ at a certain moment during polishing, and the curve (a) in the curve of the graph of FIG. 9 is the reflection spectrum obtained. In the graph of FIG. 9, the horizontal axis is the wavelength, and the vertical axis is a state in which ion-exchanged water is interposed instead of the polishing agent, and a silicon wafer on which aluminum is formed is placed on the window portion of the polishing body. The reflection spectroscopic spectrum of the light returning to the device 39 for measuring the polishing state at the time is set as the reference reflection spectroscopic spectrum, and is the intensity ratio of the measured reflection spectroscopic spectrum to the reference reflection spectroscopic spectrum. In-situ measurement of the residual film thickness of the thermal oxide film on the silicon wafer was possible from the waveform fitting by simulation. However, after the 120th silicon wafer was dressed, scratches began to appear on the window, and the 150th silicon wafer was polished, and the acquired reflection spectrum became as shown by the curve (b) in FIG. Increased probability of measurement error.

Then, when the in-situ measurement was performed by switching to the window 11b of the opening 13b where the recess amount in the initial state was 0.3 mm, the in-situ measurement without error was possible as before. It was

Further, after the 260th silicon wafer was subjected to dressing processing after polishing, the window 1 of the opening 13b was opened.
1b was scratched, and the 280th silicon wafer was polished to window 11b.
The measurement was difficult due to the decrease in the transmittance.

Again, in the initial state, the opening 13 with a recess amount of 0.45 mm
When switching to the window 11c of c and performing in-situ measurement, in-situ measurement was possible as before.

Finally, in the window 11c of the opening 13c, up to the polishing process and the dressing process of the 450th silicon wafer.
In-situ measurement was possible.

Example 2 As the polishing body according to the third embodiment of the present invention, polishing body IC1000 / SUBA400 manufactured by Rodel Co. was used, and the polishing body was provided with one opening.

A window 21 made of polyurethane shown in FIG. 3 was installed. The amount of depression of the window 21 from the surface of the polishing body 22 to the surface on the side of the object to be polished was set to be 0.15 mm, 0.3 mm, and 0.45 mm in each of 21a, 21b, and 21c.

After that, the above-mentioned polishing body 22 was set on the surface plate of the flattening apparatus according to the fourth embodiment of the present invention. Polishing of a 6-inch silicon wafer having a thermal oxide film formed to 1 μm is performed under the following conditions, and the residual film thickness on the silicon wafer is measured by the device 39 that measures the polishing state using the portion 21a of the window 21.
-Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min.

The average polishing rate at this time was 430 nm / min. After polishing, use a diamond whetstone with an abrasive grain size of # 100
Dressing was performed for 1 minute.

Each time a new 6 μm thick thermal oxide film was formed.
When the above polishing process and dressing process were repeated using an inch silicon wafer, scratches began to occur on the 21a portion of the window 21 by the dressing after polishing the 120th silicon wafer, and the window 21 was polished by the 150th silicon wafer. The probability of error in in-situ measurement was increased due to the decrease of the transmittance of the part 21a.

Then, when the in-situ measurement was carried out by switching to the portion 21b in which the recess amount in the initial state was 0.3 mm, the in-situ measurement without error was possible as before.

Further, after the 260th silicon wafer was subjected to the dressing process after polishing, scratches began to appear on the 21b portion of the window 21, and the 280th silicon wafer was polished so that the 21b portion of the window 21 was transparent. The decrease in the rate increased the probability of errors in in-situ measurement.

Again, when the in-situ measurement was performed by switching to the portion 21c of the window 21 where the recess amount in the initial state was 0.45 mm, the in-situ measurement without error was possible as before. It was

Finally, in the portion 21c of the window 21, in-situ measurement was possible up to the polishing process of the 450th silicon wafer.

Example 3 A polishing body IC1000 / SUBA400 manufactured by Rodel was used as a polishing body according to the fifth embodiment of the present invention, and one opening was provided in the polishing body.

As shown in FIG. 4, a window 41 made of polyurethane was diagonally arranged. The amount of depression from the surface of the polishing body 42 to the surface of the window on the side of the polishing object is 0.1 mm at the minimum (41a portion),
The maximum length is 0.5 mm (41d part).

After that, the polishing body 42 was set on the surface plate of the flattening apparatus according to the sixth embodiment of the present invention. Polishing of a 6-inch silicon wafer having a thermal oxide film formed to 1 μm is performed under the following conditions, and the residual film thickness on the silicon wafer is measured by the device 39 for observing the polishing state using the portion 41a of the window 41.
-Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min.

The average polishing rate at this time was 430 nm / min. After polishing, use a diamond whetstone with an abrasive grain size of # 100
Dressing was performed for 1 minute.

Each time a new 6 μm thick thermal oxide film was formed.
When the above polishing step and dressing step were repeated using an inch silicon wafer, the transmittance of the portion 41a of the window 41 decreased from the dressing of the 50th silicon wafer after polishing, and the 70th silicon wafer As a result of polishing, the probability of error in in-situ measurement increased due to the decrease in transmittance.

Then, when the in-situ measurement was performed by switching to the portion 41b where the transmittance equal to that at the initial stage of polishing was obtained, the in-situ measurement was possible as before.

Further, when the 110th silicon wafer was dressed after polishing, the transmittance decreased, and the 140th silicon wafer decreased in transmittance due to the decrease in transmittance.
The probability of error in situ measurement increased.

Again, the window 41 with which the transmittance equivalent to the initial value can be obtained
When the in-situ measurement was performed by switching to the part 41c, the in-situ measurement was possible without error as before.

By repeating the above operation, in-situ measurement was possible until the polishing treatment of the 650th silicon wafer finally.

[Embodiment 4] In the flattening apparatus (FIG. 6) according to the ninth embodiment of the present invention, a window support 62 is attached to an electric stage 61 having a stroke of 10 mm, and an acrylic window 63 is provided on the upper end thereof. I placed it.

A device 39 for observing the polishing state is provided under the surface plate 36.
Further, a device 68 for detecting the distance between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished is arranged. A sensor utilizing an autofocus mechanism was used as the device 68 for detecting the interval.

Then, a polishing body 69 (IC1000 / SUBA400 manufactured by Rodel Co.) having openings corresponding to the size of the window 63 was set on the surface plate 36. Window 63 by signal from device 68 for detecting distance
The control of the interval was set so that the interval between the surface of the window 63 on the side of the object to be polished and the polished surface of the silicon wafer was always controlled to 0.2 mm.

Thereafter, 150-inch 6-inch silicon wafers each having a thermal oxide film formed thereon of 1 μm are continuously polished one by one under the following conditions, and the residual film thickness of the silicon wafers is measured in- Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min.

After completion of polishing, dressing was carried out for 1 minute with a diamond grindstone of abrasive grain size # 100.

As a result, from the measurement of the thickness of the polishing body before and after polishing, the polishing body was worn by 0.17 mm by polishing and dressing, but the window 63 was not scratched.

FIG. 10 is a graph of a reflection spectrum from a silicon wafer surface measured in-situ at a certain moment during polishing. In the graph of FIG. 10, the horizontal axis is the wavelength and the vertical axis is a state in which ion-exchanged water is interposed instead of the polishing agent, and a silicon wafer on which aluminum is formed is placed on the window portion of the polishing body. The reflection spectroscopic spectrum of the light returning to the device 39 for measuring the polishing state at the time is set as the reference reflection spectroscopic spectrum, and is the intensity ratio of the measured reflection spectroscopic spectrum to the reference reflection spectroscopic spectrum. In all of the polishing of 150 silicon wafers, the reflection spectrum as shown by the curve (a) in FIG. 10 was obtained at a certain moment when the same time had passed from the start of polishing, and good in-situ measurement was performed. .

[Embodiment 5] In the flattening apparatus according to the tenth embodiment of the present invention, when the window 63 is located below the silicon wafer, the surface of the window on the side of the object to be polished and the object to be polished are The distance between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished was controlled to be 0.5 mm when the distance between the object and the polishing surface was 0.1 mm. The flattening apparatus of the fifth embodiment has the same structure as the flattening apparatus of the fourth embodiment.

Thereafter, 150-inch 6-inch silicon wafers each having a thermal oxide film formed thereon of 1 μm were continuously polished one by one under the following conditions, and the residual film thickness of the silicon wafers was measured by the device 39 for observing the polishing state. Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min, dressing conditions: 1 minute each time one silicon wafer is polished with a diamond grindstone of abrasive grain size # 100.

As a result, from the measurement of the thickness of the polishing body before and after polishing, the polishing body was worn by 0.15 mm by polishing and dressing, but the window 63 was not scratched. Further, in all of the polishing of 150 silicon wafers, a reflection spectrum as shown by the curve (b) in FIG. 10 was obtained at a certain moment when the same time elapsed from the start of polishing, and good in-situ measurement was performed. I was broken.

[Embodiment 6] In the flattening apparatus according to the eleventh embodiment of the present invention, a thickness is provided at the upper end of the window fixing barrel 71.
A 0.2 mm transparent rubber window 72 was attached, and a glass window 73 was attached to the lower end.

A polishing body 75 (IC1000 / SUBA400 manufactured by Rodel Co.) having an opening portion according to the size of the transparent rubber window 72 is stool 36
A transparent rubber window 72 when decompressing (normal pressure)
The distance from the surface of the object to be polished to the surface of the polishing body 75 is
The window fixing cylinder 71 was arranged in the opening 77 of the surface plate 36 so as to be 0.6 mm.

When the silicon wafer 33 is above the opening 77, the pressure in the window fixing cylinder 72 is increased, and the surface of the transparent rubber window 72 on the side of the object to be polished comes into close contact with the polishing surface of the silicon wafer 33. Was set.

Thereafter, 150-inch continuous 6-inch silicon wafers each having a thermal oxide film of 1 μm formed are continuously polished one by one under the following conditions, and the residual film thickness of the silicon wafers is measured by the device 39 for measuring the polishing state. Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min, dressing conditions: 1 minute each time one silicon wafer is polished with a diamond grindstone of abrasive grain size # 100.

As a result, from the measurement of the thickness of the polishing body before and after polishing, the polishing body was worn by 0.16 mm by polishing and dressing, but the window 72 was not scratched. In addition, in all polishing of 150 silicon wafers, a reflection spectrum as shown by the curve (c) in FIG. 10 was obtained at a certain moment when the same time elapsed from the start of polishing, and good in-situ measurement was performed. I was broken.

[Comparative Example 1] Polishing body IC1000 / SUBA400 manufactured by Rodel Co. was used as a polishing body, and one opening was provided in the polishing body. A window made of polyurethane was placed in the opening of the polishing body so that the recessed amount from the surface of the polishing body to the surface of the window on the side of the polishing object was 10 μm or less.

Next, the above-mentioned polishing body was set on the surface plate of the flattening apparatus (FIG. 2) according to the second embodiment. After this, polishing of a 6-inch silicon wafer having a thermal oxide film of 1 μm is performed under the following conditions to remove the residual film thickness of the silicon wafer.
Measured in-situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min.

The average polishing rate at this time was 430 nm / min.

After completion of polishing, dressing was carried out for 1 minute with a diamond grindstone of abrasive grain size # 100. As a result, the surface of the window on the side of the object to be polished was scratched and became opaque. At this time, the total transmitted light amount of the light transmitted through the window was 5% or less with respect to the total transmitted light amount before dressing (when the surface of the window on the side of the object to be polished is not scratched).

The second polishing was performed under the same polishing conditions as above, but in-situ measurement of the residual film thickness on the silicon wafer was impossible.

[Comparative Example 2] As a polishing body, a polishing body IC1000 / SUBA400 manufactured by Rodel Co. was used, and one opening was provided in the polishing body. A window made of acrylic was placed in the opening of the polishing body so that the recess amount from the surface of the polishing body to the surface of the window on the side of the polishing object was 0.1 mm.

Next, the above polishing body was attached to the surface plate of the flattening apparatus (FIG. 2) according to the second embodiment.

After that, 150 6-inch silicon wafers each having a thermal oxide film of 1 μm formed were continuously polished under the following conditions,
The residual film thickness of the silicon wafer was measured in-situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, rocking of the polishing head: none, polishing time: 90 seconds, polishing agent used: Cabot's SS25 diluted twice with ion exchange water, polishing agent flow rate: 200 ml
/ Min, dressing conditions: 1 minute each time one silicon wafer is polished with a diamond grindstone of abrasive grain size # 100.

As a result, scratches were generated on the window after polishing 17 sheets. When polishing was further continued, the amount of reflected light from the silicon wafer was attenuated at the 53rd wafer, making in-situ measurement difficult. When I checked the window, it looked like frosted glass due to scratches from the dressing. From the measurement of the thickness of the polishing body before and after polishing, the polishing body was worn by 0.05 m due to polishing and dressing.

[0192]

As described above, according to the polishing body and the flattening apparatus according to the present invention, the surface of the window on the side of the object to be polished is recessed with respect to the surface of the polishing body, and the recessed amount is stepwise. Or it is changing continuously. Then, when observing the polishing state of the polishing object by the device for measuring the polishing state by optically observing the polishing surface of the polishing object through the window, the window or the window When the window or that part of the window is scratched by dressing or polishing using the part without scratches, observe the polishing state of the polishing object with the device that measures the polishing state in the initial state. Switch to a window or window that has a different amount of dents and is not scratched. As a result, in-situ measurement of the polishing state can be performed, and the frequency of exchanging the polishing body or the window can be reduced, so that the cost required for polishing can be reduced.

According to the flattening apparatus of the present invention,
It has a moving device for moving the position of the surface of the window on the side of the object to be polished. Then, when observing the polishing state of the polishing target with a device that measures the polishing state by optically observing the polishing surface of the polishing target through the window, the surface of the window on the polishing target side and the polishing target By keeping the gap between the polishing surface of the object and the abrasion of the surface of the polishing object at a constant value at all times,
Further, in synchronization with the rotation of the surface plate, the distance between the surface of the window and the surface of the polishing body is dynamically controlled. As a result, the surface of the window on the object-to-be-polished side is not scratched by dressing or polishing, and the in-situ measurement of the polishing state can be performed, so that the frequency of replacement of the polishing body or the window can be reduced. This has the effect that the cost required for polishing can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a polishing body according to a first embodiment of the present invention. 1 (a) is a top view, FIG. 1 (b) is a sectional view of the A-O portion of FIG. 1 (a), and FIG. 1 (c) is a B-O portion of FIG. 1 (a). FIG. 1C is a sectional view, and FIG. 1C is a sectional view of a C-O portion of FIG.

FIG. 2 is a schematic configuration diagram of a flattening device according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a polishing body according to a third embodiment of the present invention. 3A is a top view, and FIG. 3B is a cross-sectional view of a portion D-E of FIG. 3A.

FIG. 4 is a diagram showing a polishing body according to a fifth embodiment of the present invention. 4A is a top view, and FIG. 4B is a cross-sectional view of the F-G portion of FIG. 4A.

FIG. 5 is a diagram showing a polishing body according to a seventh embodiment of the present invention. 5 (a) is a top view, and FIG. 5 (b) is a cross-sectional view of the HI portion of FIG. 5 (a).

FIG. 6 is a cross-sectional view near an opening 66 of a surface plate 36 of a flattening device according to a ninth embodiment of the present invention.

FIG. 7 (a) is a sectional view around an opening 77 of a surface plate 36 of a flattening apparatus according to an eleventh embodiment of the present invention.
FIG. 7B is a diagram showing a state when the object to be polished comes over the opening.

FIG. 8 is a flowchart showing a semiconductor device manufacturing process.

FIG. 9 is a reflection spectroscopy spectrum obtained by in-situ measurement at a certain moment during polishing. The curve (a) is in- in Example 1.
It is a reflection spectrum when measurement is possible in situ, and a reflection spectrum when curve (b) of Example 1 is difficult to measure.

FIG. 10 is a reflection spectrum obtained by in-situ measurement at a certain moment during polishing. The curve (a) shows Example 4,
The curve (b) is the reflection spectrum in Example 5, and the curve (c) is the reflection spectrum in Example 6.

FIG. 11 is a conceptual diagram of a planarization technique in a semiconductor manufacturing process and is a cross-sectional view of a semiconductor device. Figure 11
(A) is an example of planarizing an interlayer insulating film on the surface of a semiconductor device. FIG. 11B shows an example of polishing a metal film on the surface of a semiconductor device to form a so-called damascene.

FIG. 12 is a schematic configuration diagram of a conventional flattening apparatus used for CMP.

[Explanation of symbols]

11a, 11b, 11c, 21, 41, 51, 63 windows 13a, 13b, 13c, 38, 66, 77 openings 12, 22, 42, 52, 69, 75, 137 Polished body 31, 131 Polishing member 32, 132 Polishing head 33, 133 Polishing object (silicon wafer) 34, 134 Abrasive supply section 35, 135 Abrasive (slurry) 36, 136 surface plate 39, 139 Device for observing polishing state 61 Moving device 62 window support 64 O-ring 68 Interval detection device 71 Window fixed tube 72 transparent rubber window 73 glass window 74 Pneumatic control device 121 Silicon wafer 122 Interlayer insulation film 123 metal film 124 Semiconductor device

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/304 B24B 37/00 B24B 37/04

Claims (33)

(57) [Claims] 1. A load is applied between the polishing body and the polishing object in a state where an abrasive is interposed between the polishing body and the polishing object installed on a surface plate, and A polishing body for use in a flattening device for polishing the object to be polished by relative movement, having one or more openings and a window installed in the opening, the surface of the polishing body The surface of the window on the side of the object to be polished is recessed, and the amount of the recess is changed stepwise or continuously. 2. The polishing body according to claim 1, wherein the recess amount is changed stepwise by varying the recess amount for each opening. 3. The polishing body according to claim 1, wherein the recess amount is changed stepwise because the recess amount is different in two or more portions within the same opening. 4. The window is a parallel plate-shaped transparent plate, and the window is installed obliquely with respect to the surface of the polishing body so that the amount of recess is continuously changed. The polishing body according to claim 1. 5. A polishing body and a polishing pair installed on a surface plate.
In the state where an abrasive is interposed between the elephant and the elephant,
Apply a load to the object to be polished and move it relatively.
Flattening device for polishing the object to be polished by polishing
In the polishing body used for An opening, A window installed in the opening, On the side of the object to be polished of the window with respect to the surface of the polishing body
The surface is recessed, and the window is laminated with two or more transparent materials.
Between the transparent materials, which are transparent plates on parallel flat plates
Is characterized by being laminated with an adhesive force that allows peeling
Polished body. 6. A minimum dent amount dmin of the dent amounts.
Is 0 μm <dmin ≦ 400 μm
The abrasive body according to any one of 1 to 4 . 7. The amount d0 of the depression is 0 μm <d0 ≦ 400
to be μm The abrasive body according to claim 5, which is characterized in that. 8. The maximum dent amount dmax of the dent amounts
Is 0 μm <dmax ≦ 90% of the thickness of the polishing body,
Moreover, the minimum thickness tmin of the window is tmin ≧ 10% of the thickness of the polishing body, wherein
The polishing body according to any one of 1 to 4 . 9. The dent depth d0 is 0 μm <d0 ≤ polishing
90% of the body thickness, and the window thickness t0
Is characterized by t0 ≧ 10% of the thickness of the polishing body,
The polishing body according to claim 5. 10. The transmittance of at least a portion of the window is 22% or more.
9. The polishing body according to any one of 9 above. 11. The polishing body according to any one of claims 1 to 10, characterized in that the anti-reflection film on the opposite side of the object to be polished of the window is formed. 12. A load is applied between the polishing body and the object to be polished in a state where an abrasive is interposed between the polishing body and the object to be polished installed on a surface plate, and In a flattening device for polishing the object to be polished by relative movement, one or more openings formed in the surface plate, one or more openings formed in the polishing body, and the polishing body A window that is installed or that is installed on the surface plate so as to close at least a part of the opening formed in the polishing body, and an optical surface for polishing the polishing surface of the polishing object through the window. And a device for measuring a polishing state by observing, the opening formed in the polishing body and the opening formed in the surface plate are overlapped, with respect to the surface of the polishing body The surface of the window on the side of the object to be polished is dented, and the amount of dent is uneven. A flattening device characterized by being changed stepwise or continuously. 13. The flattening apparatus according to claim 12 , wherein the recess amount is changed stepwise because the recess amount is different for each opening formed in the polishing body. 14. The flattening apparatus according to claim 12 , wherein the recess amount is changed stepwise by differentiating the recess amount in two or more portions in the same opening. 15. The window is a parallel plate-shaped transparent plate, and the window is installed obliquely with respect to the surface of the polishing body, so that the recess amount is continuously changed. The flattening device according to claim 12 . 16. Polishing body and polishing installed on the surface plate
In the state where the abrasive is interposed between the object and the polishing body,
Between the object and the object to be polished, and relative movement
A flattening device for polishing the object to be polished by
In the An opening formed on the surface plate, An opening formed in the polishing body, It is installed on the polishing body or is shaped on the polishing body.
The opening is formed so as to close at least a part of the opening.
Windows installed on the surface plate, The polishing surface of the polishing object is optically observed through the window.
And a device for measuring the polishing state, Formed on the surface plate and the opening formed in the polishing body,
The opened opening overlaps, On the side of the object to be polished of the window with respect to the surface of the polishing body
The surface is concave, Parallel plate shape in which the window is formed by laminating two or more transparent materials
It is a transparent plate of The transparent materials are laminated with a peelable adhesive force.
A flattening device. 17. The dent amount d in a portion of the window through which light from the device for measuring the polishing state passes is 0 μm.
<Claim 12, characterized in that the d ≦ 400 [mu] m 1
The flattening apparatus according to any one of 5 above. 18. The recess amount d0 of the recess is 0 μm <d0 ≦ 40
The flattening according to claim 16, wherein the flatness is 0 μm.
apparatus. 19. The maximum dent amount dmax of the dent amounts
Is 0 μm <dmax ≦ 90% of the thickness of the polishing body, and the minimum thickness tmin of the window thickness is tm
16. The planarization apparatus according to claim 12, wherein in ≧ 10% of the thickness of the polishing body. 20. The dent depth d0 is 0 μm <d0 ≦
90% of the thickness of the polished body, and the thickness of the window
It is specified that t0 is t0 ≧ 10% of the thickness of the polishing body.
The flattening device according to claim 16, which is a characteristic. 21. The window, planarization apparatus according to claim 12, wherein 20 to be a resin having a polishing properties equivalent to the polishing characteristics of the polishing body. 22. A load is applied between the polishing body and the object to be polished in a state where an abrasive is interposed between the polishing body and the object to be polished installed on a surface plate, and In a flattening device that polishes the object to be polished by relative movement, one or more openings formed in the surface plate, one or more openings formed in the polishing body, and the polishing body A window installed so as to close at least a part of the formed opening, an apparatus for optically observing the polishing surface of the polishing object through the window to measure the polishing state, and the window A moving device that moves the position of the surface on the side of the object to be polished, the opening formed in the polishing body and the opening formed in the surface plate are overlapped, the window is It is installed on the surface plate through the moving device, That planarization apparatus. 23. An apparatus for detecting a gap between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished, a device for detecting a worn state of the polishing body, or a device for detecting both of them. claim 22, characterized in that it has further
The flattening apparatus according to. 24. The flattening apparatus according to claim 23 , further comprising a control device that controls a distance between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished. 25. The control device predicts the amount of wear of the polishing body from polishing conditions, polishing time, dressing conditions and dressing time, and polishes the surface of the window on the side of the polishing target and the polishing target. 25. The flattening device according to claim 24 , wherein a distance between the flat surface and the surface is controlled. 26. The control device controls the moving device so that a distance between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished is constant. The flattening apparatus according to 24 . 27. The controller controls the distance between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished in synchronization with the rotation of the surface plate.
The flattening apparatus according to 24 . Distance d between the polishing surface of the 28. The object of polishing and the polishing object side surface of the window, either of claims 22, characterized in that the 0μm ≦ d ≦ 400μm 27 of The flattening device described. 29. The distance d between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished is 0 μm ≦ d ≦ 90% of the thickness of the polishing body, and , The thickness of the window t
Is flattening device according to any one of 10% of the length of the thickness of t ≧ the polishing body, claim 22 which is a 27. 30. Light emitted from the polishing state measuring device passes through the window, passes through the abrasive between the window and the object to be polished, and is emitted on a polishing surface of the object to be polished. Reflecting, passing through the polishing agent between the window and the polishing object again, passing through the window again, returning to the apparatus for measuring the polishing state, and emitting from the apparatus for measuring the polishing state claims 12, wherein the ratio of the intensity of light returning to the device for measuring the polished state to the intensity of light is 5% or more 2
9. The flattening device according to any one of 9 above. 31. An antireflection film is formed on a surface of the window opposite to the object to be polished.
31. The flattening apparatus according to any one of 12 to 30 . 32. A method of manufacturing a semiconductor device, comprising a step of flattening a surface of a semiconductor silicon wafer by using the flattening apparatus according to any one of claims 12 to 29 . 33. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 32 .