JP2001308168A - Ceramic substrate for semiconductor manufacturing and inspecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic substrate of which breakdown voltage can be kept sufficiently high even if the diameter of the largest pore is 50 μm or less and larger than that of a conventional substrate, whose fracture toughness value can be increased since it has pores, which can resist thermal shock and further whose warpage at high temperature can be reduced. SOLUTION: The ceramic substrate on the surface or inside of which a conductor is formed is made of nitride ceramic containing oxygen and the diameter of its maximum pore is 50 μm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Detailed description of the invention]

[0002]

2. Description of the Related Art Semiconductors are extremely important products required in various industries.
The silicon wafer is manufactured by slicing a silicon single crystal to a predetermined thickness to produce a silicon wafer, and then forming a plurality of integrated circuits and the like on the silicon wafer.

In the manufacturing process of this semiconductor chip,
Various processes such as etching and CVD are performed on the silicon wafer placed on the electrostatic chuck to form a conductive circuit, an element, and the like. At that time, since corrosive gases are used as deposition gas, etching gas, etc., it is necessary to protect the electrostatic electrode layer from corrosion by these gases, and to induce adsorption force. The electrostatic electrode layer is usually covered with a ceramic dielectric film or the like.

[0004]

Conventionally, a nitride ceramic has been used as the ceramic dielectric film. However, conventionally, the dielectric film was formed by firing without adding an oxide or the like. Most of the pores formed inside the dielectric film are communicated with each other, and there are many open pores. When such pores are present, when the volume resistivity of the dielectric layer decreases at a high temperature, electrons easily fly through the air in the pores by applying a voltage, and so-called sparks are caused. If is not small, it is difficult to keep the withstand voltage of the ceramic dielectric film high.

For example, Japanese Patent Application Laid-Open No. 5-8140 discloses that
An electrostatic chuck using a nitride having a very small pore diameter of 5 μm or less, the maximum pore diameter, is disclosed.
It has been found that such a problem is found not only in the electrostatic chuck but also in a ceramic substrate for a semiconductor manufacturing / inspection apparatus in which a conductor is formed on the surface or inside of the ceramic substrate.

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, it has been found that sintering can be advanced by adding an oxide to a nitride ceramic and firing it. It has been newly found that the communicating pores are almost eliminated, independent pores are formed, and the oxide is present at the boundary of the ceramic particles, so that the withstand voltage at a high temperature can be ensured even if the pore diameter becomes large. Reached.

That is, the present invention relates to a ceramic substrate having a conductor formed on the surface or inside of a ceramic substrate, wherein the ceramic substrate is made of a non-oxide ceramic containing oxygen and has a maximum pore diameter. Is 5
A ceramic substrate for a semiconductor manufacturing / inspection device, which is not more than 0 μm.

Preferably, the non-oxide ceramic is a nitride ceramic or a carbide ceramic. The ceramic substrate preferably contains 0.05 to 10% by weight of oxygen. The ceramic substrate preferably has a porosity of 5% or less. The ceramic substrate is preferably used in a temperature range of 100 to 700C. The ceramic substrate is 25m thick
m and a diameter of 200 mm or more. The ceramic substrate preferably has a plurality of through holes into which lifter pins of a semiconductor wafer are inserted.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The ceramic substrate for a semiconductor manufacturing / inspection apparatus of the present invention is a ceramic substrate having a conductor formed on the surface or inside of the ceramic substrate. It is made of an oxide ceramic and has a maximum pore diameter of 50 μm or less.

In the ceramic substrate of the present invention, no pores are present, or when pores are present, the maximum pore diameter is 50 μm or less. If there are no pores,
The withstand voltage at a high temperature is particularly high, and conversely, when pores are present, the fracture toughness value is high. Or either the design for this may be determined in consideration of the required properties. The reason why the fracture toughness value is increased by the presence of the pores is not clear, but it is presumed that the extension of the crack is stopped by the pores.

In the ceramic substrate of the present invention, it is preferable to use a nitride ceramic or a carbide ceramic containing oxygen. This is because sintering can be advanced by containing oxygen, communicating pores are almost eliminated, and independent pores are formed, so that the corrosive gas does not erode the conductor. Further, it is because electrons are less likely to jump in the pores in the independent pores than in the continuous vents. Further, by allowing the oxide to be present at the boundary between the ceramic particles, it is possible to ensure a withstand voltage at high temperatures even if the pore diameter increases.

[0012] In the ceramic substrate of the present invention, the pore diameter of the maximum pore must be 50 µm or less. When the maximum pore diameter exceeds 50 μm, 100-700 ° C.
This is because withstand voltage characteristics at a high temperature of 200 ° C. or more cannot be ensured. The pore diameter of the largest pore is 10μ.
m or less is desirable. This is because the amount of warpage at 100 to 700 ° C., particularly at 200 ° C. or higher, is reduced.

The porosity and pore diameter of the maximum pores are adjusted by the pressurizing time, pressure and temperature during sintering, but are adjusted with respect to the nitride ceramic by using additives such as SiC and BN. SiC
And BN inhibit sintering, so that pores can be introduced.

The measurement of the pore diameter of the maximum pore is performed by preparing five samples, polishing the surface of the sample to a mirror surface, and photographing the surface at 10 places with an electron microscope at a magnification of 2000 to 5000 times. Then, the largest pore diameter was selected in the photographed photograph, and the average of 50 shots was defined as the largest pore diameter.

In the above ceramic substrate, 0.05 to 10
%, Particularly preferably 0.1 to 5% by weight of oxygen. If the amount is less than 0.1% by weight, the withstand voltage cannot be ensured in some cases. On the other hand, if the amount exceeds 5% by weight, the withstand voltage may also decrease due to a decrease in the high-temperature withstand voltage characteristics of the oxide. Because. On the other hand, if the oxygen content exceeds 5% by weight, the thermal conductivity may decrease, and the temperature raising / lowering characteristics may decrease.

The ceramic substrate has a porosity of 5%.
% Is desirable. If it exceeds 5%, the number of pores increases, and the pore diameter becomes too large. As a result, the pores easily communicate with each other and the withstand voltage decreases. The porosity is measured by the Archimedes method. Pulverize the sintered body, put the pulverized material in an organic solvent or mercury, measure the volume, calculate the true specific gravity from the weight and volume of the pulverized material, and calculate the porosity from the true specific gravity and the apparent specific gravity .

[0017] The ceramic substrate is 100-700 ° C.
It is desirable to use in the temperature range. This is because the withstand voltage decreases in such a temperature range, and the configuration of the present invention is particularly advantageous. The ceramic substrate is 1
It is desirable that the amount of warpage at 00 to 700 ° C. is small.
This is because when the ceramic substrate is used for a heater or an electrostatic chuck, the semiconductor wafer can be uniformly heated. When the amount of warpage is large, the semiconductor wafer does not adhere to the heating surface of the heater, so that the semiconductor wafer cannot be heated uniformly, or when the semiconductor wafer is heated while being separated from the heating surface, the semiconductor wafer is heated. This is because the distance from the surface becomes uneven and the semiconductor wafer cannot be heated uniformly. The amount of warpage when the temperature of the ceramic substrate is raised to 100 to 700 ° C. and returned to room temperature (25 ° C.) (that is, the difference in the amount of warpage before and after the temperature rise) is preferably 7 μm or less.

The ceramic substrate of the present invention can be used for semiconductor manufacturing and
It can be used for inspection, and can be used for electrostatic chucks, hot plates (ceramic heaters), ceramic plates for wafer probers (hereinafter simply referred to as wafer probers), and the like.

The thickness of the ceramic substrate of the present invention is as follows:
50 mm or less, especially 25 mm or less is desirable. In particular, when the thickness of the ceramic substrate exceeds 25 mm, the heat capacity of the ceramic substrate becomes large, and in particular, when the temperature control means is provided for heating and cooling, the temperature followability is reduced due to the large heat capacity. is there. In addition, the problem of warpage due to the presence of pores solved by the ceramic substrate of the present invention,
This is because it is unlikely to occur with a thick ceramic substrate having a thickness exceeding 25 mm. Particularly, 5 mm or less is optimal. The thickness is desirably 1 mm or more.

The diameter of the ceramic substrate of the present invention is 200 m.
m or more is desirable. In particular, it is desirable to be 12 inches (300 mm) or more. This is because it will become the mainstream of next-generation silicon wafers. In addition, the problem of warping in a high temperature region that is solved by the present invention is because it hardly occurs in a ceramic substrate having a diameter of 200 mm or less.

The ceramic substrate desirably has a plurality of through holes for inserting lifter pins of a semiconductor wafer. This is because the presence of the through holes releases strain during processing and tends to cause warpage particularly when the Young's modulus is lowered at a high temperature, and it is considered that the present invention is the most effective structure.

As the nitride ceramic constituting the ceramic substrate of the present invention, a metal nitride ceramic, for example,
Examples include aluminum nitride, silicon nitride, boron nitride, and titanium nitride.

In the ceramic substrate of the present invention, it is desirable that the ceramic substrate contains a sintering aid. Alkali metal oxides, alkaline earth metal oxides, and rare earth oxides can be used as the sintering aid. Among these sintering aids, CaO, Y ₂ O ₃ , Na ₂
O, Li ₂ O and Rb ₂ O are preferred. Also, alumina may be used. The content of these is 0.1 to 2
0% by weight is desirable.

In the ceramic substrate of the present invention, it is desirable that the ceramic substrate contains 5-5000 ppm of carbon. By containing carbon, the ceramic substrate can be blackened, and radiant heat can be sufficiently utilized when used as a ceramic heater. The carbon may be amorphous or crystalline. When amorphous carbon is used, a decrease in volume resistivity at high temperatures can be prevented, and when crystalline carbon is used, a decrease in thermal conductivity at high temperatures can be prevented. Because. Therefore, depending on the application, both crystalline carbon and amorphous carbon may be used in combination. Further, the content of carbon is more preferably 50 to 2000 ppm.

When carbon is contained in the ceramic substrate, it is desirable that carbon be contained so that its brightness becomes N6 or less as a value based on the provisions of JIS Z 8721. What has this level of brightness is the amount of radiant heat,
This is because the concealing property is excellent. Here, the lightness N is set to 0 for an ideal black lightness and 10 for an ideal white lightness.
Between these black lightness and white lightness, each color is divided into ten so that the perception of the brightness of the color becomes equal, and N0 to N0
This is indicated by the symbol N10. The actual measurement of the lightness is performed by comparing with color patches corresponding to N0 to N10. In this case, the first decimal place is 0 or 5.

In the ceramic substrate of the present invention, the silicon wafer is placed in contact with the wafer mounting surface of the ceramic substrate, and the silicon wafer is supported by lifter pins or the like, as shown in FIG. In some cases, it may be held at a constant distance from the substrate. FIG.
1 is a partially enlarged cross-sectional view schematically showing a ceramic heater which is an example of the ceramic substrate of the present invention.

In FIG. 13, the lifter pin 9 is inserted into the through hole 95.
6 are inserted to hold the silicon wafer 99. By moving the lifter pins 96 up and down, the silicon wafer 99 is received from the transfer machine, the silicon wafer 99 is placed on the ceramic substrate 91, and the silicon wafer 9
9 while supporting it. A heating element 92 is formed on the bottom surface 91 a of the ceramic substrate 91, and a metal coating layer 92 a is provided on the surface of the heating element 92. A bottomed hole 94 is provided, into which a thermocouple is inserted. The silicon wafer 99 is heated on the wafer heating surface 91b side. It should be noted that the semiconductor manufacturing of the present invention
When the ceramic substrate for an inspection apparatus is used for a ceramic heater, the semiconductor wafer and the heating surface can be separated. The separation distance is desirably 50 to 5000 μm. In addition, the present invention is particularly effective for such separation. This is because the amount of warpage of the ceramic substrate at a high temperature is small, and the distance between the semiconductor wafer and the heating surface becomes uniform.

When the ceramic substrate of the present invention is used as a hot plate (ceramic heater), the conductor is a heating element, and may be a metal layer having a thickness of about 0.1 to 100 μm. Good. When used as an electrostatic chuck, the conductor is an electrostatic electrode, and R
The F electrode and the heating element may be formed below the electrostatic electrode and as a conductor in the ceramic substrate. further,
When used as a wafer prober, a chuck top conductor layer is formed as a conductor on the surface, and a guard electrode and a ground electrode are formed inside as a conductor. The ceramic substrate of the present invention is optimally used at a temperature of 100 ° C. or higher, preferably 200 ° C. or higher.

Hereinafter, the present invention will be described with reference to an electrostatic chuck and a wafer prober having a hot plate function.

In the electrostatic chuck according to the present invention, an electrostatic electrode is formed on a ceramic substrate, and a ceramic dielectric film covering the electrostatic electrode has a non-oxide ceramic containing oxygen, such as a nitride ceramic or a carbide. Since it is made of ceramic and has a porosity of 5% or less and a maximum pore diameter of 50 μm or less, the pores in this dielectric film are:
It is composed of mutually independent pores. Therefore,
Gas or the like that lowers the withstand voltage does not permeate the electrostatic electrode by permeating the ceramic dielectric film, and does not lower the withstand voltage of the ceramic dielectric film even at a high temperature. Also, by setting the thickness of the ceramic dielectric film to 50 to 5000 μm, a sufficient withstand voltage can be secured without lowering the chucking force.

FIG. 1 is a longitudinal sectional view schematically showing an electrostatic chuck which is an embodiment of the ceramic substrate of the present invention, and FIG. 2 is a sectional view of the electrostatic chuck shown in FIG.
FIG. 3 is a sectional view taken along line BB of the electrostatic chuck shown in FIG. 1.

In the electrostatic chuck 101, a chuck positive electrode electrostatic layer 2 is formed on the surface of a ceramic substrate 1 having a circular shape in plan view.
And a chuck negative electrode electrostatic layer 3 are formed, and a ceramic dielectric film 4 made of a nitride ceramic containing oxygen is formed so as to cover the electrostatic electrode layer. A silicon wafer 9 is placed on the electrostatic chuck 101 and is grounded.

As shown in FIG. 2, the chuck positive electrode electrostatic layer 2 includes a semicircular arc portion 2a and a comb tooth portion 2b, and the chuck negative electrostatic layer 3 also includes a semicircular arc portion 3a and a comb tooth portion. Part 3b
The chuck positive electrode electrostatic layer 2 and the chuck negative electrode electrostatic layer 3 are arranged to face each other so as to intersect the comb teeth portions 2b and 3b. Each of the negative electrode electrostatic layers 3 has a DC power supply of +
The side - the side are connected, the DC voltage V ₂ is adapted to be applied.

In order to control the temperature of the silicon wafer 9, a resistance heating element 5 having a concentric circular shape in a plan view as shown in FIG. 3 is provided inside the ceramic substrate 1. at both ends of the external terminal pin 6 is connected, is fixed, so that the voltages V ₁ is applied. Although not shown in FIGS. 1 and 2, the ceramic substrate 1 has a bottomed hole 11 for inserting a temperature measuring element and a lifter pin for supporting and lowering the silicon wafer 9 as shown in FIG. (Not shown) through hole 12 for insertion
Are formed. Note that the resistance heating element 5 may be formed on the bottom surface of the ceramic substrate.

When the electrostatic chuck 101 is operated, a DC voltage V ₂ is applied to the chuck positive electrostatic layer 2 and the chuck negative electrostatic layer 3. As a result, the silicon wafer 9 is adsorbed and fixed to these electrodes via the ceramic dielectric film 4 by the electrostatic action of the chuck positive electrode electrostatic layer 2 and the chuck negative electrode electrostatic layer 3. . After fixing the silicon wafer 9 on the electrostatic chuck 101 in this manner, various processes such as CVD are performed on the silicon wafer 9.

The electrostatic chuck according to the present invention has, for example, a configuration as shown in FIGS. Hereinafter, each member constituting the electrostatic chuck, and
Other embodiments of the electrostatic chuck according to the present invention will be sequentially described in detail.

The ceramic dielectric film used in the electrostatic chuck according to the present invention is preferably made of a nitride ceramic containing oxygen, and has a maximum pore diameter of 50 μm.
It is as follows. The thickness is preferably 50 to 1500 μm, and the porosity is preferably 5% or less.

Examples of the nitride ceramic include metal nitride ceramics, for example, aluminum nitride, silicon nitride, boron nitride, titanium nitride and the like. Of these, aluminum nitride is most preferred. This is because the withstand voltage is high and the thermal conductivity is the highest at 180 W / m · K.

The above nitride ceramic contains oxygen. For this reason, the sintering of the nitride ceramic is facilitated, and even when the nitride ceramic contains pores, the pores become independent pores, and thus the withstand voltage is improved for the above-described reason.

In order to make the above-mentioned nitride ceramic contain oxygen, usually, the raw material powder of the nitride ceramic is heated in oxygen or air, or a metal oxide is mixed into the raw material powder of the nitride ceramic, followed by firing. Do. Examples of the metal oxide include yttria (Y ₂ O ₃ ), alumina (Al ₂ O ₃ ), rubidium oxide (Rb ₂ O), lithium oxide (Li ₂ O), calcium carbonate (CaCO ₃ ), and the like. Can be The addition amount of these metal oxides is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the nitride ceramic.

The porosity of the ceramic dielectric film is desirably 5% or less. In addition, the thickness is 50-50
It is preferable that the maximum pore diameter is not more than 50 μm. The thickness of the ceramic dielectric film is 5
If the thickness is less than 0 μm, a sufficient withstand voltage cannot be obtained because the film thickness is too thin, and the dielectric breakdown of the ceramic dielectric film may occur when the silicon wafer is placed and adsorbed.
If the thickness of the ceramic dielectric film exceeds 5000 μm, the distance between the silicon wafer and the electrostatic electrode becomes long, and the ability to adsorb the silicon wafer is reduced. The thickness of the ceramic dielectric film is 100 to 1500 μ
m is more preferred.

When the porosity exceeds 5%, the number of pores increases and the pore diameter becomes too large.
The pores are easily communicated with each other. With a ceramic dielectric film having such a structure, the withstand voltage is reduced. further,
When the pore diameter of the largest pore exceeds 50 μm, it is not possible to ensure a withstand voltage at high temperatures even if the oxide exists at the grain boundary. The porosity is 0.001 to 0.001 if porosity exists.
3% is more preferable, and the pore diameter of the maximum pore is 0.1 to 1
0 μm is more preferred.

It is desirable that the ceramic dielectric film contains 50 to 5000 ppm of carbon. This is because the electrode pattern provided in the electrostatic chuck can be hidden and high radiation heat can be obtained.
In addition, the lower the volume resistivity, the higher the silicon wafer adsorption capacity in a low temperature range.

In the electrostatic chuck according to the present invention, a certain amount of pores may be present in the ceramic dielectric film because the fracture toughness value can be increased, and the thermal shock resistance Can be improved.

Examples of the electrostatic electrode formed on the ceramic substrate include a sintered body of metal or conductive ceramic, a metal foil, and the like. The metal sintered body is preferably made of at least one selected from tungsten and molybdenum. It is desirable that the metal foil is also made of the same material as the metal sintered body. This is because these metals are relatively hard to be oxidized and have sufficient conductivity as electrodes.
As the conductive ceramic, at least one selected from carbides of tungsten and molybdenum can be used.

FIGS. 8 and 9 are horizontal sectional views schematically showing electrostatic electrodes in another electrostatic chuck.
In the electrostatic chuck 20 shown in FIG. 9, a semicircular chuck positive electrode electrostatic layer 22 and a chuck negative electrode electrostatic layer 23 are formed inside the ceramic substrate 1. In the electrostatic chuck shown in FIG. Are formed with chuck positive electrode electrostatic layers 32a and 32b and chuck negative electrode electrostatic layers 33a and 33b each having a shape obtained by dividing a circle into four parts. Further, the two positive electrode electrostatic layers 22a and 22b and the two chuck negative electrode electrostatic layers 33a and 33b are formed to cross each other. In the case of forming an electrode in which a circular electrode or the like is divided, the number of divisions is not particularly limited, and may be five or more, and the shape is not limited to a sector.

The ceramic substrate used in the electrostatic chuck according to the present invention is preferably made of a nitride ceramic or a carbide ceramic.

As the above-mentioned nitride ceramic, for example,
Examples include aluminum nitride, silicon nitride, boron nitride, and titanium nitride. Examples of the carbide ceramic include silicon carbide, boron carbide, titanium carbide, and tungsten carbide. Further, it is desirable that the ceramic dielectric film and the ceramic substrate are made of the same material. This is because nitride ceramics have high thermal conductivity and can transmit heat generated by the resistance heating element satisfactorily. Further, when the ceramic dielectric film and the ceramic substrate are made of the same material, an electrostatic chuck can be easily manufactured by laminating green sheets manufactured by the same method and firing them under the same conditions. . Also, among nitride ceramics, aluminum nitride is most preferred. This is because the thermal conductivity is the highest at 180 W / m · K.

In the above ceramic substrate, 5
It is desirable to contain 0 to 5000 ppm. This is because high radiation heat can be obtained. As the carbon, either crystalline or non-crystalline amorphous which can be detected by X-ray diffraction may be used, or both crystalline and amorphous may be used.

The electrostatic chuck according to the present invention is usually provided with a temperature control means such as a resistance heating element as shown in FIG. This is because it is necessary to perform a CVD process or the like while heating the silicon wafer placed on the electrostatic chuck.

As the temperature control means, in addition to the resistance heating element 5 shown in FIG. 3, a Peltier element (see FIG. 6) can be mentioned. The resistance heating element may be provided inside the ceramic substrate, or may be provided on the bottom surface of the ceramic substrate. When a resistance heating element is provided, a blowing port for a refrigerant such as air may be provided as a cooling means in a support container into which the electrostatic chuck is fitted.

When the resistance heating element is provided inside the ceramic substrate, a plurality of layers may be provided. In this case, it is desirable that the patterns of the respective layers are formed so as to complement each other, and that the pattern is formed on any layer when viewed from the heating surface. For example, the structure is a staggered arrangement.

Examples of the resistance heating element include a sintered body of metal or conductive ceramic, a metal foil, a metal wire, and the like. As the metal sintered body, at least one selected from tungsten and molybdenum is preferable. This is because these metals are relatively hard to oxidize and have a resistance value sufficient to generate heat.

The conductive ceramic may be at least one selected from carbides of tungsten and molybdenum.
Seeds can be used. Further, when a resistance heating element is formed on the bottom surface of the ceramic substrate, it is desirable to use a noble metal (gold, silver, palladium, platinum) or nickel as the metal sintered body. Specifically, silver, silver-palladium, or the like can be used. The metal particles used in the metal sintered body may be spherical, scaly, or a mixture of spherical and scaly.

A metal oxide may be added to the metal sintered body. The use of the metal oxide is for bringing the ceramic substrate and the metal particles into close contact. Although the reason why the metal oxide improves the adhesion between the ceramic substrate and the metal particles is not clear, the surface of the metal particles has a slight oxide film formed thereon, and the ceramic substrate is formed of an oxide. Of course, even in the case of a non-oxide ceramic, an oxide film is formed on the surface. Therefore, it is considered that this oxide film is sintered and integrated on the surface of the ceramic substrate via the metal oxide, so that the metal particles and the ceramic substrate adhere to each other.

As the metal oxide, for example, oxidized
Lead, zinc oxide, silica, boron oxide (B ₂O₃), Al
At least one selected from Mina, Yttria and Titania
Species are preferred. These oxides have the resistance value of the resistance heating element.
Between the metal particles and the ceramic substrate without increasing the
This is because adhesion can be improved.

The content of the metal oxide is desirably 0.1 to less than 10 parts by weight based on 100 parts by weight of the metal particles. By using a metal oxide in this range,
This is because the resistance value does not become too large and the adhesion between the metal particles and the ceramic substrate can be improved.

The ratio of lead oxide, zinc oxide, silica, boron oxide (B ₂ O ₃ ), alumina, yttria, and titania is such that when the total amount of metal oxide is 100 parts by weight, 10 parts by weight, 1 to 30 parts by weight of silica, 5 to 50 parts by weight of boron oxide, 20 to 7 parts of zinc oxide
0 parts by weight, alumina 1 to 10 parts by weight, yttria 1
-50 parts by weight and titania of 1-50 parts by weight are preferred.
However, it is desirable that the total be adjusted so that the total does not exceed 100 parts by weight. This is because these ranges can particularly improve the adhesion to the ceramic substrate.

When the resistance heating element is provided on the bottom surface of the ceramic substrate, it is desirable that the surface of the resistance heating element 15 be covered with a metal layer 150 (see FIG. 4). The resistance heating element 15 is a sintered body of metal particles, and is easily oxidized when exposed, and the oxidation changes the resistance value. Therefore, by covering the surface with the metal layer 150, oxidation can be prevented.

The thickness of the metal layer 150 is 0.1 to 10 μm
Is desirable. This is because the oxidation of the resistance heating element can be prevented without changing the resistance value of the resistance heating element. The metal used for coating may be a non-oxidizing metal. Specifically, gold, silver, palladium, platinum,
At least one selected from nickel is preferred.
Among them, nickel is more preferable. The resistance heating element requires a terminal for connection to a power supply, and this terminal is attached to the resistance heating element via solder. Nickel prevents thermal diffusion of the solder. As connection terminals, terminal pins made of Kovar can be used.

When the resistance heating element is formed inside the heater plate, the surface of the resistance heating element is not oxidized, so that the coating is unnecessary. When the resistance heating element is formed inside the heater plate, a part of the surface of the resistance heating element may be exposed.

As the metal foil used as the resistance heating element, it is desirable to use a nickel foil or a stainless steel foil as a resistance heating element by forming a pattern by etching or the like. The patterned metal foil may be bonded with a resin film or the like. Examples of the metal wire include a tungsten wire and a molybdenum wire.

When a Peltier element is used as the temperature control means, heat is generated by changing the direction of current flow.
This is advantageous because both cooling can be performed. As shown in FIG. 6, the Peltier element 8 is composed of p-type and n-type thermoelectric elements 81.
Are connected in series and joined to a ceramic plate 82 or the like. Examples of the Peltier element include a silicon-germanium-based material, a bismuth-antimony-based material, and a lead / tellurium-based material.

In the electrostatic chuck according to the present invention, for example, as shown in FIG. 1, a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3 are provided between a ceramic substrate 1 and a ceramic dielectric film 4. An electrostatic chuck 101 having a configuration in which a resistance heating element 5 is provided inside a ceramic substrate 1;
As shown in FIG. 4, a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3 are provided between a ceramic substrate 1 and a ceramic dielectric film 4, and a resistance heating element 15 is provided on the bottom surface of the ceramic substrate 1. Electrostatic chuck 201 having the configuration shown in FIG.
As shown in FIG. 2, a chuck positive electrode electrostatic layer 2 and a chuck negative electrode electrostatic layer 3 are provided between a ceramic substrate 1 and a ceramic dielectric film 4, and a metal wire 7 serving as a resistance heating element is provided inside the ceramic substrate 1. Chuck 30 having a structure in which is embedded
1. As shown in FIG. 6, a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3 are provided between a ceramic substrate 1 and a ceramic dielectric film 4, and a thermoelectric element 81 is provided on the bottom surface of the ceramic substrate 1. Peltier element 8 made of ceramic plate 82
And the like.

In the electrostatic chuck according to the present invention, FIGS.
As shown in FIG. 2, the chuck positive electrode electrostatic layer 2 and the chuck negative electrode electrostatic layer 3 are provided between the ceramic substrate 1 and the ceramic dielectric film 4, and the resistance heating element 5 and the metal wires are provided inside the ceramic substrate 1. 7 are formed, connecting portions (through holes) 16, 1, and 1 for connecting these to external terminals.
7 is required. The through holes 16 and 17 are made of a high melting point metal such as tungsten paste and molybdenum paste,
It is formed by filling a conductive ceramic such as tungsten carbide or molybdenum carbide.

The connecting portions (through holes) 16 and 17
Is preferably 0.1 to 10 mm. This is because cracks and distortion can be prevented while preventing disconnection. The external terminal pins 6 and 18 are connected using the through holes as connection pads (see FIG. 7D).

The connection is made by solder or brazing material. As brazing materials, silver brazing, palladium brazing, aluminum brazing,
Use gold brazing. As the gold solder, an Au-Ni alloy is desirable. This is because the Au-Ni alloy has excellent adhesion to tungsten.

The ratio of Au / Ni is [81.5-82.
5 (% by weight)] / [18.5 to 17.5 (% by weight)] is desirable. The thickness of the Au—Ni layer is desirably 0.1 to 50 μm. This is because the range is sufficient to secure the connection.
Also, at a high vacuum of ^10-6 to ^10-5 Pa, 500 to 10
When used at a high temperature of 00 ° C., the Au—Cu alloy deteriorates, but the Au—Ni alloy is advantageous because such deterioration does not occur. The total amount of impurity elements in the Au—Ni alloy is 1
When the amount is 00 parts by weight, it is desirably less than 1 part by weight.

In the ceramic substrate of the present invention, a thermocouple can be embedded in the bottomed hole 11 of the ceramic substrate 1 as necessary. This is because the temperature of the resistance heating element can be measured using a thermocouple, and the temperature and the amount of current can be changed based on the data to control the temperature. The size of the junction of the metal wires of the thermocouple is preferably equal to or larger than the element diameter of each metal wire and 0.5 mm or less. With such a configuration, the heat capacity of the junction is reduced, and the temperature is accurately and quickly converted to a current value. Therefore, the temperature controllability is improved and the temperature distribution on the heating surface of the semiconductor wafer is reduced. As the thermocouple, for example, JIS-C-1602 (198
0), K type, R type, B type, S type, E type
Type, J type, and T type thermocouples.

FIG. 10 is a sectional view schematically showing a supporting container 41 for disposing the electrostatic chuck according to the present invention having the above-described structure. The electrostatic chuck 101 is fitted into the support container 41 via a heat insulating material 45. The support container 11 has a refrigerant outlet 42 formed therein. The refrigerant is blown from the refrigerant inlet 44 and passes through the refrigerant outlet 42 to the outside through the suction port 43. The operation of the coolant can cool the electrostatic chuck 101.

Next, an example of a method for manufacturing an electrostatic chuck according to the present invention will be described with reference to the sectional view shown in FIG. (1) First, a ceramic powder of a nitride ceramic is mixed with a binder and a solvent to obtain a green sheet 50. As the ceramic powder described above, for example, aluminum nitride or the like can be used, and if necessary,
A sintering aid such as yttria may be added.

Since several or one green sheet 50 ′ to be laminated on the green sheet on which the electrostatic electrode layer printed body 51 described later is formed is a layer to be the ceramic dielectric film 4, It is assumed that the oxide powder is mixed with the product powder. Usually, it is desirable to use the same material for the ceramic dielectric film 4 and the material for the ceramic substrate 1. This is because these are often sintered together, and the firing conditions are the same. However, when the materials are different, it is also possible to manufacture a ceramic substrate first, form an electrostatic electrode layer thereon, and further form a ceramic dielectric film thereon.

The binder is preferably at least one selected from an acrylic binder, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol.
Further, as the solvent, at least one selected from α-terpineol and glycol is desirable. A paste obtained by mixing these is formed into a sheet shape by a doctor blade method to produce a green sheet 50.

The green sheet 50 may be provided with a through hole for inserting a lifter pin of a silicon wafer or a concave portion for burying a thermocouple as necessary. The through holes and the concave portions can be formed by punching or the like. The thickness of the green sheet 50 is preferably about 0.1 to 5 mm.

Next, a conductor paste serving as an electrostatic electrode layer and a resistance heating element is printed on the green sheet 50. The printing is performed so as to obtain a desired aspect ratio in consideration of the shrinkage ratio of the green sheet 50, thereby obtaining the electrostatic electrode layer print body 51 and the resistance heating element layer print body 52. The printed body is formed by printing a conductive paste containing conductive ceramic, metal particles, and the like.

As the conductive ceramic particles contained in these conductor pastes, carbides of tungsten or molybdenum are most suitable. This is because it is hard to be oxidized and the thermal conductivity is hard to decrease. Further, as the metal particles, for example, tungsten, molybdenum, platinum, nickel and the like can be used.

The average particle size of the conductive ceramic particles and metal particles is preferably 0.1 to 5 μm. This is because it is difficult for these particles to print the conductor paste even if they are too large or too small. As such a paste, 85 to 97 parts by weight of metal particles or conductive ceramic particles, 1.5 to 10 parts by weight of at least one binder selected from acrylic, ethyl cellulose, butyl cellosolve and polyvinyl alcohol, α-terpineol, glycol A conductor paste prepared by mixing 1.5 to 10 parts by weight of at least one solvent selected from ethyl alcohol and butanol is most suitable. Further, the holes formed by punching or the like are filled with a conductive paste to obtain through-hole prints 53 and 54.

Next, as shown in FIG.
A green sheet 50 having 1, 52, 53, 54;
The green sheet 50 'is laminated. The reason why the green sheet 50 'having no printed body is laminated on the side where the resistance heating element is formed is to prevent the end face of the through hole from being exposed and being oxidized during firing for forming the resistance heating element. is there.
If baking for forming the resistance heating element is performed while the end face of the through hole is exposed, it is necessary to sputter a metal that is difficult to oxidize, such as nickel, and more preferably to coat it with Au-Ni gold solder. Is also good.

(2) Next, as shown in FIG. 7B, the laminate is heated and pressed to sinter the green sheet and the conductive paste. Heating temperature is 1000-20
The temperature and the pressure are preferably 100 to 200 kg / cm ^{2 at} 00 ° C., and the heating and pressurization are performed in an inert gas atmosphere. As the inert gas, argon, nitrogen, or the like can be used. In this step, the through holes 16, 1
7, a chuck positive electrode electrostatic layer 2, a chuck negative electrode electrostatic layer 3, a resistance heating element 5, and the like are formed.

(3) Next, as shown in FIG. 7C, blind holes 13 and 14 for connecting external terminals are provided. Blind hole 1
At least a part of the inner walls of the electrodes 3 and 14 are made conductive, and the conductive inner walls are connected to the chuck positive electrostatic layer 2, the chuck negative electrostatic layer 3, the resistance heating element 5, and the like. desirable.

(4) Finally, as shown in FIG.
External terminals 6 and 18 are provided in blind holes 13 and 14 via a brazing filler metal. Further, if necessary, a bottomed hole 11 can be provided, and a thermocouple can be embedded therein. Solder is silver-lead,
Alloys such as lead-tin and bismuth-tin can be used. Note that the thickness of the solder layer is desirably 0.1 to 50 μm. This is because the range is sufficient to secure the connection by soldering.

In the above description, the electrostatic chuck 101
(See FIG. 1), the electrostatic chuck 201 (see FIG.
In the case of manufacturing, a ceramic plate having an electrostatic electrode layer is manufactured, and then a conductive paste is printed and fired on the bottom surface of the ceramic plate to form a resistance heating element 15, and thereafter, electroless plating or the like is performed. May be used to form the metal layer 150. When the electrostatic chuck 301 (see FIG. 5) is manufactured, a metal foil or a metal wire may be embedded in a ceramic powder as an electrostatic electrode or a resistance heating element and sintered. Further, when manufacturing the electrostatic chuck 401 (see FIG. 6), after manufacturing a ceramic plate having an electrostatic electrode layer, a Peltier element may be joined to this ceramic plate via a sprayed metal layer.

When a conductor is provided on the surface and inside of the ceramic substrate of the present invention, and when the inside conductor is at least one of a guard electrode and a ground electrode, the ceramic substrate is replaced with a wafer prober. Function as

FIG. 11 is a cross-sectional view schematically showing one embodiment of the wafer prober according to the present invention, and FIG.
FIG. 12 is a sectional view taken along line AA of the wafer prober shown in FIG. 11. In the wafer prober 601, the grooves 6 having a concentric circular shape in plan view are formed on the surface of the ceramic substrate 63 in a circular shape in plan view.
7 are formed, and a plurality of suction holes 68 for sucking the silicon wafer are provided in a part of the groove 67, and most of the ceramic substrate 63 including the groove 67 is connected to an electrode of the silicon wafer. Are formed in a circular shape.

On the other hand, on the bottom surface of the ceramic substrate 63, a heating element 69 having a concentric circular shape in plan view as shown in FIG. 3 is provided to control the temperature of the silicon wafer. Are connected and fixed to external terminal pins (not shown). The ceramic substrate 6
Inside 3, a guard electrode 65 and a ground electrode 66 (see FIG. 7) having a lattice shape in plan view are provided for removing stray capacitors and noise. Guard electrode 65
The material of the ground electrode 66 may be the same as that of the electrostatic electrode.

The thickness of the chuck top conductor layer 62 is
1 to 20 μm is desirable. If the thickness is less than 1 μm, the resistance value becomes too high to function as an electrode, while if it exceeds 20 μm, the conductor tends to be peeled off due to the stress of the conductor.

As the chuck top conductor layer 62, for example, copper, titanium, chromium, nickel, a noble metal (gold, silver,
At least one metal selected from refractory metals such as platinum, molybdenum, and the like can be used.

In the wafer prober having such a configuration, after a silicon wafer having an integrated circuit formed thereon is mounted thereon, a probe card having tester pins is pressed against the silicon wafer, and a voltage is applied while heating and cooling. To conduct a continuity test. In the case of manufacturing a wafer prober, for example, similarly to the case of an electrostatic chuck, first, a ceramic substrate in which a resistance heating element is embedded is manufactured, and then, a groove is formed on the surface of the ceramic substrate, and then, Then, a metal layer may be formed by applying sputtering, plating, or the like to the surface portion where the groove is formed.

[0089]

The present invention will be described in more detail below. (Example 1 and Comparative Example 1) Electrostatic chuck (see FIG. 1)
(1) Aluminum nitride powder fired in air at 500 ° C. for 0, 1, and 7 hours (manufactured by Tokuyama Corporation, average particle size 1.1 μm)
m) 100 parts by weight, yttria (average particle size: 0.4 μm)
m) Using a paste obtained by mixing 4 parts by weight, 11.5 parts by weight of an acrylic binder, 0.5 parts by weight of a dispersant, and 53 parts by weight of alcohol composed of 1-butanol and ethanol, molding was performed by a doctor blade method, Thickness 0.
A 47 mm green sheet was obtained.

(2) Next, the green sheet is heated to 80 ° C.
After drying for 5 hours, punch 1.8m in diameter
A portion serving as a through hole for inserting a lifter pin of a semiconductor wafer having a length of 3.0 mm or 5.0 mm and a portion serving as a through hole for connecting to an external terminal were provided.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm, acrylic binder 3.0
By weight, 3.5 parts by weight of the α-terpineol solvent and 0.3 parts by weight of the dispersant were mixed to prepare a conductor paste A. A conductive paste B was prepared by mixing 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of an α-terpineol solvent, and 0.2 parts by weight of a dispersant. This conductor paste A was printed on a green sheet by screen printing to form a conductor paste layer. The printing pattern was a concentric pattern. Further, a conductor paste layer composed of an electrostatic electrode pattern having the shape shown in FIG. 2 was formed on another green sheet.

Further, a conductive paste B was filled in a through hole for a through hole for connecting an external terminal. On the green sheet 50 after the above processing, 34 green sheets 50 ′ on which the conductor paste A is not printed are laminated on the upper side (heating surface) and 13 green sheets 50 ′ are laminated on the lower side. A green sheet 50 on which a paste layer is printed is laminated, and two green sheets 50 'on which a tungsten paste is not printed are further laminated thereon, and these are pressed at 130 [deg.] C. under a pressure of 80 kg / cm < ² > to form a laminate. Was formed (FIG. 7A).

(4) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 0 to 1 ° C.
Hot pressing was performed at 50 kg / cm ² (details in Table 1) for 3 hours to obtain an aluminum nitride plate having a thickness of 3 mm. This is cut out into a disk shape of 230 mm and the thickness is 6 μm inside.
A plate made of aluminum nitride having a resistance heating element 5 having a width of 10 mm, a chuck positive electrostatic layer 2 having a thickness of 10 μm, and a chuck negative electrostatic layer 3 was formed (FIG. 7B).

(5) Next, the plate obtained in (4) is
After polishing with a diamond grindstone, a mask is placed and Si
A bottomed hole (diameter: 1.2 mm, depth: 2.0 mm) for a thermocouple was provided on the surface by blasting treatment with C or the like.

(6) Further, the portions where the through holes are formed are cut out to form blind holes 13 and 14 (FIG. 7).
(C)) External holes 6 and 18 made of Kovar were connected to the blind holes 13 and 14 by heating and reflowing at 700 ° C. using gold solder made of Ni—Au (FIG. 7D). In addition,
The connection of the external terminals is preferably a structure in which a tungsten support is supported at three points. This is because connection reliability can be ensured.

(7) Next, a plurality of thermocouples for temperature control were embedded in the bottomed holes, and the manufacture of the electrostatic chuck having the resistance heating element was completed. The porosity, pore diameter, withstand voltage, fracture toughness value, adsorption force, temperature rise characteristics, and warpage of the electrostatic chuck having the resistance heating element thus manufactured were measured by the following methods. The results are shown in Tables 1 and 2 below. The amount of oxygen contained in the ceramic substrate varies depending on the time for firing the aluminum nitride powder, and the values are shown in Table 1. In the thermal conductivity measurement by the laser flash method, 180 to 200 W / m
-It was K.

(Example 2 and Comparative Example 2) Production of an electrostatic chuck (see FIG. 4) (1) Aluminum nitride powder fired in air at 500 ° C. for 0, 1, and 7 hours (manufactured by Tokuyama Corporation, average particle size) 1.1μ
m) 100 parts by weight, yttria (average particle size: 0.4 μm)
m) 4 parts by weight, 11.5 parts by weight of an acrylic binder, 0.5 parts by weight of a dispersant, 0, 3, 5% by weight of BN (details in Table 3) and 53 parts by weight of an alcohol composed of 1-butanol and ethanol Was molded by a doctor blade method using a paste obtained by mixing the above, to obtain a green sheet having a thickness of 0.47 mm.

(2) Next, the green sheet is heated to 80 ° C.
After drying for 5 hours, punch 1.8m in diameter
A portion serving as a through hole for inserting a lifter pin of a semiconductor wafer having a length of 3.0 mm or 5.0 mm and a portion serving as a through hole for connecting to an external terminal were provided.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm, acrylic binder 3.0
By weight, 3.5 parts by weight of the α-terpineol solvent and 0.3 parts by weight of the dispersant were mixed to prepare a conductor paste A. A conductive paste B was prepared by mixing 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of an α-terpineol solvent, and 0.2 parts by weight of a dispersant. This conductor paste A was printed on a green sheet by screen printing to form a conductor paste layer composed of an electrostatic electrode pattern having the shape shown in FIG.

Further, the conductive paste B was filled in a through hole for a through hole for connecting an external terminal. On the green sheet after the above processing, a green sheet on which the conductor paste A is not printed is further placed on the upper side (heating surface).
Sheets, 48 sheets are laminated on the lower side, and these are stacked at 130 ° C.
/ Cm ² to form a laminate.

(4) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 0 to 1 ° C.
Hot pressing was performed at 50 kg / cm ² (details in Table 3) for 3 hours to obtain a 3 mm-thick aluminum nitride plate. This is cut out into a 230 mm disc, and the thickness is 15 μm
Of aluminum nitride having chuck positive electrode electrostatic layers 32a and 32b and chuck negative electrode electrostatic layers 33a and 33b (see FIG. 9).

(5) A mask was placed on the bottom of the plate obtained in (4) above, and a concave portion (not shown) for a thermocouple was provided on the surface by blasting with SiC or the like.

(6) Next, the resistance heating element 15 was printed on the surface (bottom surface) facing the wafer mounting surface. For printing, a conductor paste was used. As the conductive paste, Solvest PS603D manufactured by Tokuri Chemical Laboratory, which is used for forming through holes in a printed wiring board, was used. This conductor paste
It is a silver / lead paste, and a metal oxide composed of lead oxide, zinc oxide, silica, boron oxide, and alumina (the weight ratio of each is 5/55/10/25/5) is 7 to 100 parts by weight of silver. 0.5 parts by weight. The silver had a scaly shape with an average particle size of 4.5 μm.

(7) The plate on which the conductive paste is printed is
By heating and baking at 80 ° C., silver and lead in the conductor paste were sintered and baked on a ceramic substrate. Further, the plate was immersed in an electroless nickel plating bath comprising an aqueous solution containing 30 g / l of nickel sulfate, 30 g / l of boric acid, 30 g / l of ammonium chloride and 60 g / l of Rochelle salt, and the surface of the silver sintered body 15 was immersed. A nickel layer 150 having a thickness of 1 μm and a boron content of 1% by weight or less was deposited.
Thereafter, the plate was subjected to annealing at 120 ° C. for 3 hours. A resistance heating element made of a silver sintered body has a thickness of 5 mm.
μm, a width of 2.4 mm, and a sheet resistivity of 7.7 mΩ /
It was □.

(8) Next, blind holes for exposing the through holes 16 were formed in the ceramic substrate. N
Using a gold solder made of an i-Au alloy (81.5% by weight of Au, 18.4% by weight of Ni, 0.1% by weight of impurities),
After heating and reflow at 0 ° C., external terminal pins made of Kovar were connected. Also, external terminal pins made of Kovar were formed on the resistance heating element via solder (tin 9 / lead 1).

(9) Next, a plurality of thermocouples for temperature control were buried in the concave portions to obtain the electrostatic chuck 201. The porosity, pore diameter, withstand voltage, fracture toughness value, adsorption force, temperature rise characteristics, and warpage of the electrostatic chuck having the resistance heating element thus manufactured were measured by the following methods. The results are shown in Tables 3 and 4 below. The amount of oxygen contained in the ceramic substrate varies depending on the time for firing the aluminum nitride powder, and the values are shown in Table 3.

(10) Next, this electrostatic chuck 201 is mounted on a stainless steel supporting container 41 having a sectional shape shown in FIG.
Was inserted through a heat insulating material 45 made of ceramic fiber (trade name: IBIWOOL, manufactured by IBIDEN). This support container 41 has a refrigerant outlet 42 for cooling gas,
The temperature of the electrostatic chuck 201 can be adjusted. The resistance heating element 15 of the electrostatic chuck 201 fitted in the support container 41 was energized to raise the temperature, and the temperature of the electrostatic chuck 201 was controlled by flowing a coolant through the support container. Temperature could be controlled.

Example 3 and Comparative Example 3 Production of Electrostatic Chuck 301 (See FIG. 5) (1) Two electrodes having the shape shown in FIG. 8 were formed by punching a 10 μm-thick tungsten foil. did. The two electrodes and the tungsten wire were placed in air at 500 ° C.
100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle diameter 1.1 μm) and 4 parts by weight of yttria (average particle diameter 0.4 μm) fired for 1, 7 hours, and alumina 0, 1.5, 3.5, 15% by weight is put in a mold, and the pressure is 0 to 150 kg / cm in nitrogen gas at 1890 ° C.
² (Table 5 for details) Hot-press for 3 hours, 3mm thick
Was obtained. This is 230m in diameter
The plate was cut out into a circular shape of m. At this time, the thickness of the electrostatic electrode layer was 10 μm.

(2) The steps (5) to (7) of Example 1 were performed on this plate-like body to obtain an electrostatic chuck 301. The porosity, pore diameter, withstand voltage, fracture toughness value, adsorption force, temperature rise characteristics, and warpage of the electrostatic chuck having the resistance heating element thus manufactured were measured by the following methods. The results are shown in Tables 5 and 6 below. The amount of oxygen contained in the ceramic substrate varies depending on the time for firing the aluminum nitride powder.
Is shown in

[0110]Evaluation method  (1) Oxygen content A sample sintered under the same conditions as the sintered body according to the example was tanned.
Grind in a Gusten mortar and collect 0.01 g of this
Oxygen at a heating temperature of 2200 ° C and a heating time of 30 seconds.
Nitrogen simultaneous analyzer (TC-136 manufactured by LECO)
It was measured. (2) Measurement of porosity of ceramic dielectric film A ceramic dielectric film was cut out and measured by the Akimimedes method.
And the porosity was measured. Specifically, the cut sample is
Crush into powder and put into organic solvent or mercury
And then calculate the true specific gravity from the weight of the powder measured in advance.
The porosity was calculated from the measured values and the apparent specific gravity.

(3) Measurement of Pore Diameter of Ceramic Dielectric Film The electrostatic chuck was cut at several locations in the longitudinal direction, and the length of the cut pores was measured with a microscope. When the vertical and horizontal lengths were different, the maximum value was taken. (4) Evaluation of Withstand Voltage of Ceramic Dielectric Film For the electrostatic chucks manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, a metal electrode was placed on the electrostatic chuck, and the electrostatic electrode layer and the electrode were During this period, a voltage was applied, and the voltage at which dielectric breakdown occurred was measured.

(5) Fracture Toughness Value An indenter was pressed into the surface with a Vickers hardness tester (MVK-D type, manufactured by Akashi Seisakusho), and the length of the generated cracks was measured and substituted into the following formula.

Fracture toughness = 0.026 × E^1/2× 0.
5 × P^1/2× a × C^-3/2  E is Young's modulus (3.18 × 10¹¹Pa), P is pushed
Only load (98N), a is half of the diagonal length of the indentation (m),
C is half (m) of the average of the crack length.

(6) Adsorption force Load cell (Autograph AGS-5 manufactured by Shimadzu Corporation)
OA).

(7) Temperature rise characteristics The time required to raise the temperature to 450 ° C. was measured. (8) Amount of warpage After raising the temperature to 450 ° C and applying a load of 150 kg / cm ² , the temperature was cooled to 25 ° C, and the amount of warpage was measured using a shape measuring device (Nanoway manufactured by Kyocera Corporation).

[0116]

[Table 1]

[0117]

[Table 2]

[0118]

[Table 3]

[0119]

[Table 4]

[0120]

[Table 5]

[0121]

[Table 6]

As is clear from Tables 1 to 6, in the electrostatic chucks according to Examples 1 to 3, the withstand voltage of the ceramic dielectric film was 11 to 20 kV / mm at room temperature, and 1 to 10 kV / mm even at 450 ° C. mm. In the case of having pores, a fracture toughness value of 3.5 MPam ^1/2 or more can be secured. Further, by setting the pore diameter of the maximum pore to 50 μm or less, the amount of warpage at a high temperature can be reduced.
When there is no pore, the withstand voltage becomes very high, and the warpage can be almost completely eliminated.

(Embodiment 4) Electrostatic chuck 401 (FIG. 6)
Production of Example 2) Steps (1) to (5) of Example 2 (First-stage conditions in Table 3)
After that, nickel was further sprayed on the bottom surface, and thereafter, a lead / tellurium-based Peltier element was joined to obtain an electrostatic chuck 401. The thus manufactured electrostatic chuck was excellent in temperature-fall characteristics, and was cooled from 450 ° C. to 100 ° C. in 3 minutes when cooled by a Peltier device.

Embodiment 5 A wafer prober 601 (FIG. 1)
(1) Production of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), which was calcined in air at 500 ° C. for 1 hour 100
Using a doctor blade method, a mixed composition obtained by mixing 0 parts by weight, 40 parts by weight of yttria (average particle diameter: 0.4 μm), 10 parts by weight of SiC, and 530 parts by weight of an alcohol composed of 1-butanol and ethanol was mixed. Molded,
A green sheet having a thickness of 0.47 mm was obtained.

(2) Next, the green sheet is heated to 80 ° C.
After drying for 5 hours, a through hole for a through hole for connecting the heating element and the external terminal pin was provided by punching.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm, acrylic binder 3.0
By weight, 3.5 parts by weight of an α-terpineol solvent and 0.3 part by weight of a dispersant were mixed to prepare a conductor paste A. Further, 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of an α-terpineol solvent, and 0.2 parts by weight of a dispersant were mixed to prepare a conductive paste B.

Next, a grid-shaped printed body for a guard electrode and a printed body for a ground electrode were printed on the green sheet by screen printing using the conductive paste A. In addition, the conductive paste B was filled in through holes for through holes for connection with terminal pins.

Further, 50 printed green sheets and 50 unprinted green sheets were laminated and
A laminate was produced by integrating at 30 ° C. under a pressure of 80 kg / cm ² .

(4) Next, this laminate is placed in nitrogen gas for 6 hours.
Degreasing at 00 ° C for 5 hours, 1890 ° C, pressure 150kg /
It was hot-pressed at ² cm for 3 hours to obtain a 3 mm-thick aluminum nitride plate. The obtained plate-like body was prepared with a diameter of 300
It was cut out into a circular shape of mm to obtain a ceramic plate. The size of the through hole 660 is 0.2 mm in diameter,
The depth was 0.2 mm.

The guard electrode 65 and the ground electrode 66
Is 10 μm, the formation position of the guard electrode 65 is 1 mm from the wafer mounting surface, and the formation position of the ground electrode 66 is
It was 1.2 mm from the wafer mounting surface. The conductor non-forming region 66a of the guard electrode 65 and the ground electrode 66
Of one side was 0.5 mm.

(5) The plate-like body obtained in (4) is polished with a diamond grindstone, a mask is placed, and a blast treatment with SiC or the like is performed on the surface to form a concave portion for a thermocouple and a wafer suction member. Groove 67 (width 0.5 mm, depth 0.5 mm)
Was provided.

(6) Further, a layer for forming the heating element 69 was printed on the surface facing the wafer mounting surface. For printing, a conductor paste was used. As the conductive paste, Solvest PS603D manufactured by Tokuri Chemical Laboratory, which is used for forming through holes in a printed wiring board, was used. This conductor paste is a silver / lead paste, and a metal oxide composed of lead oxide, zinc oxide, silica, boron oxide, and alumina (the weight ratio of each is 5/55/10/25/5) is converted to silver 10
It contained 7.5 parts by weight with respect to 0 parts by weight. The silver had a scaly shape with an average particle size of 4.5 μm.

(7) The heater plate on which the conductor paste was printed was heated and fired at 780 ° C. to sinter silver and lead in the conductor paste and to sinter them on the ceramic substrate 63. Further, nickel sulfate 30 g / l, boric acid 30 g / l, ammonium chloride 30 g / l and Rochelle salt 60 g / l
The heater plate is immersed in an electroless nickel plating bath composed of an aqueous solution containing, and a nickel layer having a thickness of 1 μm and a boron content of 1% by weight or less (not shown) is formed on the surface of the silver sintered body 69.
Was precipitated. Thereafter, the heater plate was annealed at 120 ° C. for 3 hours. The heating element made of a silver sintered body had a thickness of 5 μm, a width of 2.4 mm, and a sheet resistivity of 7.7 mΩ / □.

(8) A titanium layer, a molybdenum layer, and a nickel layer were sequentially formed on the surface on which the grooves 67 were formed by sputtering. As a device for sputtering, SV-4540 manufactured by Japan Vacuum Engineering Co., Ltd. was used. The sputtering conditions are as follows: atmospheric pressure 0.6 Pa, temperature 100 ° C., electric power 2
00 W, and the sputtering time was adjusted for each metal within the range of 30 seconds to 1 minute. From the image of the X-ray fluorescence spectrometer, the thickness of the obtained film was 0.3 μm for the titanium layer.
m, the molybdenum layer was 2 μm, and the nickel layer was 1 μm.

(9) Nickel sulfate 30 g / l, boric acid 3
The ceramic plate obtained in the above (8) is immersed in an electroless nickel plating bath comprising an aqueous solution containing 0 g / l, ammonium chloride 30 g / l and Rochelle salt 60 g / l, and the surface of the metal layer formed by sputtering. Then, a nickel layer having a thickness of 7 μm and a boron content of 1% by weight or less was deposited and annealed at 120 ° C. for 3 hours. The surface of the heating element does not pass current and is not covered with electrolytic nickel plating.

Further, 2 g of potassium potassium cyanide /
l, 75 g / l ammonium chloride, 50 g / l sodium citrate and 10 g / l sodium hypophosphite in an electroless gold plating solution at 93 ° C. for 1 minute,
A gold plating layer having a thickness of 1 μm was formed on the nickel plating layer.

(10) An air suction hole 68 extending from the groove 67 to the back surface was formed by drilling, and a blind hole (not shown) for exposing the through hole 660 was provided.
A Ni-Au alloy (81.5% by weight of Au, Ni
An external terminal pin made of Kovar was connected by heating and reflowing at 970 ° C. using a brazing filler metal consisting of 18.4% by weight and 0.1% by weight of impurities. In addition, solder (tin 90)
(Weight% / lead 10 weight%) to form external terminal pins made of Kovar.

(11) Next, a plurality of thermocouples for temperature control were buried in the recesses to obtain a wafer prober heater 601.

The ceramic substrate thus obtained had a maximum pore diameter of 2 μm and a porosity of 1%. The temperature of the ceramic substrate was raised to 200 ° C.
No dielectric breakdown occurred even when 00V was applied. Further, the amount of warpage was good at 1 μm or less.

(Example 6 and Comparative Example 4)
100 parts by weight of silicon carbide powder (average particle size 1.1 μm, manufactured by Yakushima Denko) baked at 0 ° C. for 0, 1, and 7 hours, carbon 4
Parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.
Using a paste in which 5 parts by weight and 53 parts by weight of alcohol composed of 1-butanol and ethanol were mixed, molding was performed by a doctor blade method to obtain a green sheet having a thickness of 0.5 mm.

Then, the same processing as in (2) to (7) of Example 1 was performed to manufacture an electrostatic chuck. In addition, a glass paste was applied and laminated on a portion in contact with the conductor paste.

The porosity, pore diameter, withstand voltage, fracture toughness, adsorption force, temperature rise characteristics, and warpage of the electrostatic chuck having the resistance heating element thus manufactured were measured in the same manner as in Example 1. . The results are shown in Tables 7 and 8 below.
The amount of oxygen contained in the ceramic substrate varies depending on the time for firing the aluminum nitride powder, and the values are shown in Table 7. The withstand voltage was measured between the wafer mounting surface and the electrostatic electrode.

[0143]

[Table 7]

[0144]

[Table 8]

As is clear from Tables 7 and 8, in the electrostatic chuck according to Example 6, the withstand voltage of the ceramic dielectric film is good. Also, the fracture toughness value is 4.0 MPam.
^1/2 or more can be secured. Further, by setting the pore diameter of the maximum pore to 50 μm or less, the amount of warpage at a high temperature can be reduced.

(Example 7 and Comparative Example 5) A concave portion was formed on the surface of the electrostatic chuck of Example 1 and Comparative Example 1 by drilling, and a support pin made of alumina for supporting a silicon wafer in the concave portion. Was formed, and the distance between the silicon wafer and the surface was set to be 100 μm. Next, the voltage was applied to only the resistance heating element without applying the voltage to the electrostatic electrode and heated, the temperature of the silicon wafer was raised to 400 ° C., and the temperature difference on the surface of the silicon wafer was measured. As a result, the warpage of the ceramic substrate is 1
In the case of 0 μm, the difference in surface temperature of the silicon wafer is 3 ° C., but in the case of a warpage of 8 μm, the difference in surface temperature of the silicon wafer is as high as 10 ° C., resulting in poor uniformity of the temperature of the silicon wafer. Was.

(Test Example) As in Comparative Example 1, the aluminum nitride powder was not fired in air, but was sintered by normal pressure.
An electrostatic chuck having a thickness of 30 mm was manufactured. In addition, without sintering the aluminum nitride powder in the air, an electrostatic chuck having a diameter of 150 mm was manufactured by normal pressure sintering. All 45
Even after the temperature was raised to 0 ° C., the amount of warpage was 1 μm or less.
That is, in the case of a ceramic substrate having a thickness of more than 25 mm and a diameter of less than 200 mm, the problem of warpage does not occur in the first place. Further, an electrostatic chuck having no through-hole was manufactured, but the amount of warpage after heating to 450 ° C. was 1 μm or less. As described above, the present invention is particularly effective when the thickness is 25 m.
It is considered that a ceramic substrate for a semiconductor manufacturing / inspection apparatus having a diameter of 200 mm or less and a diameter of 200 mm or more and having a through hole is particularly effective.

[0148]

As described above, according to the ceramic substrate of the present invention, the ceramic substrate is made of a non-oxide ceramic containing oxygen, and even if the maximum pore diameter is 50 μm or less, the withstand voltage can be increased. Can be kept sufficiently large. In addition, since it has pores, the fracture toughness value can be increased, and it can withstand thermal shock. Furthermore, the amount of warpage at high temperatures can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of an electrostatic chuck according to the present invention.

FIG. 2 is a sectional view taken along line AA of the electrostatic chuck shown in FIG.

FIG. 3 is a sectional view taken along line BB of the electrostatic chuck shown in FIG. 1;

FIG. 4 is a sectional view schematically showing an example of the electrostatic chuck according to the present invention.

FIG. 5 is a sectional view schematically showing an example of the electrostatic chuck according to the present invention.

FIG. 6 is a cross-sectional view schematically showing one example of the electrostatic chuck according to the present invention.

FIGS. 7A to 7D are cross-sectional views schematically showing a part of the manufacturing process of the electrostatic chuck according to the present invention.

FIG. 8 is a horizontal sectional view schematically showing a shape of an electrostatic electrode constituting the electrostatic chuck according to the present invention.

FIG. 9 is a horizontal sectional view schematically showing the shape of an electrostatic electrode constituting the electrostatic chuck according to the present invention.

FIG. 10 is a cross-sectional view schematically showing a state where the electrostatic chuck according to the present invention is fitted into a support container.

FIG. 11 is a cross-sectional view schematically showing a wafer prober according to the present invention.

FIG. 12 is a cross-sectional view schematically showing a guard electrode of a wafer prober according to the present invention.

FIG. 13 is a cross-sectional view schematically showing a hot plate according to the present invention.

[Explanation of symbols]

 101, 201, 301, 401 Electrostatic chuck 1 Ceramic substrate 2, 22, 32a, 32b Chuck positive electrode layer 3, 23, 33a, 33b Chuck negative electrode layer 2a, 3a Semicircular portion 2b, 3b Comb portion Reference Signs List 4 ceramic dielectric film 5 resistance heating element 6, 18 external terminal pin 7 metal wire 8 Peltier element 9 silicon wafer 11 bottomed hole 12 through hole 13, 14 blind hole 15 resistance heating element 150 metal layer 16, 17 through hole 41 support Container 42 Refrigerant outlet 43 Inlet 44 Refrigerant inlet 45 Insulation material

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/66 C04B 35/56 101Y 35/58 104Y 104D 104S

Claims (8)

[Claims] 1. A ceramic substrate having a conductor formed on a surface or inside of a ceramic substrate, wherein the ceramic substrate is made of a non-oxide ceramic containing oxygen and has a maximum pore diameter of 50 μm or less. A ceramic substrate for a semiconductor manufacturing / inspection apparatus, characterized in that: 2. The ceramic substrate according to claim 1, wherein the non-oxide ceramic is a nitride ceramic. 3. The ceramic substrate according to claim 1, wherein the non-oxide ceramic is a carbide ceramic. 4. The ceramic substrate for a semiconductor manufacturing / inspection apparatus according to claim 1, which contains 0.05 to 10% by weight of oxygen. 5. The ceramic substrate for a semiconductor manufacturing / inspection apparatus according to claim 1, wherein the porosity is 5% or less. 6. The ceramic substrate for a semiconductor manufacturing / inspection apparatus according to claim 1, which is used in a temperature range of 100 to 700 ° C. 7. The semiconductor device according to claim 1, which has a thickness of 25 mm or less and a diameter of 200 mm or more.
Ceramic substrate for inspection equipment. 8. The ceramic substrate for a semiconductor manufacturing / inspection apparatus according to claim 1, comprising a plurality of through holes into which lifter pins of a semiconductor wafer are inserted.