JP2002033377A - Electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic chuck where temperature fully quickly rises and falls, even if the diameter of a ceramic substrate exceeds 190 mm, and, especially reaches 300 mm or larger. SOLUTION: In this electrostatic chuck, a temperature control means is provided on a ceramic substrate, at the same time, an electrostatic electrode is formed on the ceramic substrate, and a ceramic dielectric film is provided on the electrostatic electrode. In this case. the diameter and thickness of the ceramic substrate should be equal to at least 190 mm and 20 mm or less, respectively, and 0.1 to 20 wt.% oxygen should be contained in the ceramic dielectric film.

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,
A semiconductor wafer such as a silicon wafer is placed on an apparatus capable of performing various processes, and subjected to various processes such as etching and CVD to form a conductor circuit, an element, and the like.

At this time, the semiconductor wafer needs to be firmly fixed to the device. For this reason, an electrostatic chuck provided with an electrostatic electrode for adsorbing and fixing a semiconductor wafer inside the apparatus is widely used.

Also, oxide ceramics such as alumina, nitride ceramics, and the like are used as materials for forming the electrostatic chuck. In the electrostatic chuck using such a ceramic, an electrostatic electrode is provided on a ceramic substrate, a thin dielectric film is formed on the electrostatic electrode, and a semiconductor wafer is coulombed through the dielectric film. The force is applied to the ceramic substrate.

Further, when performing thermal CVD or the like, the semiconductor wafer must be heated. Therefore, the electrostatic chuck is usually provided with a means for heating a ceramic substrate such as a resistance heating element. I have.

In such an electrostatic chuck using ceramics, since the Young's modulus (strength) is large even at a high temperature, the thickness of the ceramic substrate can be made relatively thin, and the weight of the electrostatic chuck can be reduced. It has the feature of being able to.

[0008]

However, with the recent increase in the size of semiconductor wafers, the size of the ceramic substrate must be increased, so that the heat capacity of the electrostatic chuck increases and the voltage and current amount change. On the other hand, the temperature of the ceramic substrate does not follow quickly, and the rate of temperature rise and fall is slow, which causes a problem that productivity of semiconductor wafers and the like is reduced. Further, when the diameter of the ceramic substrate is set to be larger than 300 mm in order to accommodate a 12-inch semiconductor wafer, the temperature of the outer peripheral portion is remarkably reduced, and a problem that the temperature uniformity of the heating surface is lacking occurs. .

The present invention has been made to solve these problems, and has a ceramic substrate having a diameter of 190 m.
It is an object of the present invention to provide an electrostatic chuck in which the rate of temperature rise and fall is sufficiently fast even when the size of the chuck becomes larger than 300 m, especially more than 300 mm.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the thickness of the ceramic substrate has been reduced to 20 mm or less and the heat capacity has been further reduced, thereby increasing the temperature. The present inventors have found that it is possible to prevent a decrease in temperature-fall characteristics, and have completed the present invention.

That is, a first aspect of the present invention is an electrostatic chuck in which a temperature control means is provided on a ceramic substrate, an electrostatic electrode is formed on the ceramic substrate, and a ceramic dielectric film is provided on the electrostatic electrode. The ceramic substrate has a diameter exceeding 190 mm and a thickness of 20 mm.
mm or less in the ceramic dielectric film.
It is characterized by containing up to 20% by weight of oxygen.

According to the electrostatic chuck of the first aspect of the present invention, even if the ceramic substrate has a large diameter exceeding 190 mm, the thickness of the ceramic substrate is reduced to 20 mm or less, so that the outer peripheral portion can be formed. In this case, the temperature drop can be made as small as possible and the heat capacity can be made small, so that an electrostatic chuck capable of quickly raising and lowering the temperature can be realized. Also, when the diameter of the ceramic substrate is large, it is easy to bend under its own weight, a gap is formed between the semiconductor wafer and the ceramic substrate, it is difficult to uniformly heat the semiconductor wafer, and when the thickness of the substrate is thin, the amount of deflection is small. Increase. However, the ceramic dielectric film is
Since 0.1 to 20% by weight of oxygen is contained, the rigidity is improved and the amount of deflection can be reduced.

In the electrostatic chuck according to the first aspect of the present invention, it is preferable that a resistance heating element is used as the temperature control means. After applying the conductive paste to the green sheet or sintered body, heating and firing, or embedding the metal wire in the molded body and firing, it is possible to form the resistance heating element relatively easily. is there.

According to a second aspect of the present invention, there is provided an electrostatic chuck in which a temperature control means is provided on a ceramic substrate, an electrostatic electrode is formed on the ceramic substrate, and a ceramic dielectric film is provided on the electrostatic electrode. The ceramic substrate has a diameter of more than 300 mm and a thickness of 20 mm or less.

If the diameter of the ceramic substrate is larger than 300 mm, the area of the outer peripheral side surface becomes large and heat is taken off by contact with air, so that the temperature of the outer peripheral portion is greatly reduced. However, in the electrostatic chuck of the second aspect of the present invention, the thickness of the substrate is adjusted to 20 mm or less, the contact area between the side surface and the air is reduced, the heat is hardly dissipated, and the temperature drop in the outer peripheral portion is reduced. In addition, since the heat capacity is reduced, it is possible to realize an electrostatic chuck capable of quickly raising and lowering the temperature.

In the electrostatic chuck according to the second aspect of the present invention, the ceramic dielectric film preferably contains 0.1 to 20% by weight of oxygen. When the diameter of the ceramic substrate exceeds 300 mm, the thickness of the substrate is 2
When the thickness is 0 mm or less, the semiconductor wafer is easily bent by its own weight, and a gap is formed between the semiconductor wafer and the ceramic substrate, so that it is difficult to uniformly heat the semiconductor wafer, and the chuck force varies. Therefore, 0.1 to 20 in the ceramic dielectric film.
This is because by containing oxygen by weight, rigidity is improved, and deflection can be reduced.

In the electrostatic chuck according to the second aspect of the present invention, it is preferable that a resistance heating element is used as the temperature control means. After applying the conductive paste to the green sheet or sintered body, heating and firing, or embedding the metal wire in the molded body and firing, it is possible to form the resistance heating element relatively easily. is there.

Further, in the electrostatic chuck according to the second aspect of the present invention, the ceramic dielectric film has a thickness of 50 to 5000 μm.
It is desirable that the thickness be This is because the amount of deflection of the ceramic substrate can be reduced.

Japanese Patent Application Laid-Open No. 4-304942 discloses an electrostatic chuck made of a ceramic substrate having a thickness of 10 mm and a diameter of 150 mm. However, since the diameter is small, the problem to be solved by the present invention does not occur. . Also, in Japanese Patent Application Laid-Open No. 7-86379, the thickness is 5 m.
An electrostatic chuck made of a ceramic substrate having a diameter of 210 mm and a diameter of 210 mm is disclosed. However, the content of yttria is as small as 2% by weight and the rigidity is not sufficient. For this reason, the chuck force varies. Further, Japanese Patent Application Laid-Open No. H10-722
No. 60 discloses a ceramic substrate having a diameter of 200 mm and a thickness of 12 mm. However, there is no description of the oxygen content. Therefore, all of these known techniques relate to a substrate having a diameter of less than 300 mm, and the problem of a decrease in the temperature of the outer periphery of the substrate cannot be recalled.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an electrostatic chuck according to a first embodiment of the present invention will be described with reference to the drawings. According to a first aspect of the present invention, there is provided an electrostatic chuck in which a temperature control unit is provided on a ceramic substrate, an electrostatic electrode is formed on the ceramic substrate, and a ceramic dielectric film is provided on the electrostatic electrode. The ceramic substrate has a diameter of 1
An electrostatic chuck having a thickness of more than 90 mm and a thickness of 20 mm or less, wherein the ceramic dielectric film contains 0.1 to 20% by weight of oxygen.

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

In this electrostatic chuck 101, a semicircular arc portion 2a and a comb tooth portion 2 are formed on the surface of a disc-shaped ceramic substrate 1.
b, and an electrostatic electrode layer composed of a chuck negative electrode electrostatic layer 3 also composed of a semicircular arc-shaped part 3a and a comb tooth part 3b, and a comb tooth part 2b and a comb tooth part 3b Are formed so as to cross each other, and a thin ceramic dielectric film 4 is formed on the ceramic substrate 1 including this electrostatic electrode layer.
Are formed.

The chuck positive electrode electrostatic layer 2 and the chuck negative electrode electrostatic layer 3 respectively have a positive side and a negative side of a DC power supply.
Is connected to the side, the DC voltage V ₂ is adapted to be applied. A silicon wafer 9 is mounted on the electrostatic chuck 101 and is grounded.

On the other hand, a resistance heating element 5 having a concentric circular shape in plan view as shown in FIG. 3 is provided inside the ceramic substrate 1 for controlling the temperature of the silicon wafer 9. 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, as shown in FIG. 3, this ceramic substrate 1 supports a bottomed hole 11 for inserting a temperature measuring element and a silicon wafer 9 and moves it up and down. A through hole 12 for inserting a lifter pin (not shown) is formed. Note that the resistance heating element 5 may be formed on the bottom surface of the ceramic substrate.

Then, when a DC voltage V ₂ is applied between the chucking positive electrode electrostatic layer 2 and the chucking negative electrode electrostatic layer 3, the silicon wafer 9 moves between the chucking positive electrode electrostatic layer 2 and the chucking negative electrode electrostatic layer 3. It is adsorbed and fixed to the ceramic dielectric film 4 by an electrostatic action (Coulomb force).

The diameter of the ceramic substrate constituting the electrostatic chuck of the first invention exceeds 190 mm. This is to cope with an increase in the size of the silicon wafer. The diameter of the ceramic substrate is desirably 200 mm or more, particularly preferably greater than 200 mm. Especially 300m
m is more desirable. This is for dealing with the next generation of semiconductor wafers.

The ceramic substrate has a thickness of 20 m.
m, preferably 10 mm or less. This is because, with the enlargement of the electrostatic chuck, the thickness is reduced to reduce the heat capacity thereof. Also, if the diameter of the ceramic substrate is 3
In the case of not less than 00 mm, the area of the outer periphery becomes large, the contact area with the atmospheric gas such as air becomes large, and the temperature of the outer periphery is significantly lowered. Therefore, the contact area is reduced by reducing the thickness of the ceramic substrate. Thereby, the temperature of the outer peripheral portion is prevented from lowering. In particular, by setting the thickness to 10 mm or less, the temperature lowering characteristics are improved. The thickness of the ceramic substrate is desirably 1 to 5 mm. This is because the variation in the temperature of the heating surface is reduced.

The ceramic dielectric film constituting the first electrostatic chuck of the present invention contains 0.1 to 20% by weight of oxygen. The smaller the thickness of the substrate, the greater the amount of flexure. However, by including 0.1 to 20% by weight of oxygen, the rigidity can be improved and the flexure can be reduced.

The electrostatic chuck according to the first aspect of the present invention has the above-described configuration, and has, for example, an embodiment as shown in FIGS. In the following, each member constituting the electrostatic chuck and other embodiments of the electrostatic chuck according to the first aspect of the present invention will be sequentially described in detail.

The ceramic dielectric film constituting the electrostatic chuck according to the first aspect of the present invention is provided so as to cover the electrostatic electrodes formed on the ceramic substrate. The ceramic material forming the ceramic dielectric film is not particularly limited, and examples thereof include a nitride ceramic, a carbide ceramic, and an oxide ceramic.

Examples of the nitride ceramic include metal nitride ceramics, for example, aluminum nitride, silicon nitride, boron nitride, titanium nitride and the like. Further, as the carbide ceramic, metal carbide ceramic,
For example, silicon carbide, zirconium carbide, titanium carbide,
Examples include tantalum carbide and tungsten carbide.

Examples of the oxide ceramic include metal oxide ceramics such as alumina, zirconia, cordierite, and mullite. These ceramics may be used alone or in combination of two or more.

Of these ceramics, nitride ceramics and carbide ceramics are more preferable than oxide ceramics. This is because the thermal conductivity is high. Also, among nitride ceramics, aluminum nitride is most preferred. This is because the thermal conductivity is the highest at 180 W / m · K.

The ceramic dielectric film contains 0.1 to
Desirably, it contains 20% by weight of oxygen. 0.
If the amount is less than 1% by weight, the withstand voltage cannot be ensured. On the other hand, if the amount exceeds 5% by weight, the withstand voltage also decreases due to the decrease in the high temperature withstand voltage characteristics of the oxide. On the other hand, if the oxygen content exceeds 20% by weight, the thermal conductivity decreases and the temperature rise / fall characteristics deteriorate.

In order to make the above-mentioned nitride ceramic or carbide ceramic contain oxygen, usually, these raw material powders are heated in the air or oxygen or mixed with a raw material powder and baked. Examples of the metal oxide include yttria (Y ₂ O ₃ ) and alumina (Al
₂ O ₃ ), rubidium oxide (Rb ₂ O), lithium oxide (Li ₂ O), calcium carbonate (CaCO ₃ ) and the like. The addition amount of these metal oxides is preferably 1 to 20 parts by weight based on 100 parts by weight of the nitride ceramic.

The above dielectric film is used as a sintering aid
It may be made of silicon carbide containing B, C, Be, BeO and the like. This is because mechanical strength is high and heat resistance is excellent.

The ceramic dielectric film desirably contains carbon. If it is not desired to lower the thermal conductivity of the ceramic dielectric film at high temperatures (about 500 ° C.), it is desirable to add crystalline carbon. If it is not desired to lower the volume resistivity at high temperatures, It is desirable to add amorphous carbon. Therefore, in some cases, by adding both,
Both volume resistivity and thermal conductivity can be adjusted appropriately. Crystalline carbon can be determined by the size of the peak near 1550 cm ^-1 and near 1333 cm ^-1 when measured Raman spectrum.

When carbon is contained in the ceramic dielectric film, the content is preferably 5 to 5000 ppm. When the content of carbon is less than 5 ppm, radiant heat is reduced, and it is difficult to conceal the electrostatic electrode. On the other hand, when the content of carbon exceeds 5000 ppm, densification and reduction in volume resistivity are suppressed. It will be difficult to do. The carbon content is 100 to 2000 ppm
Is more preferred.

In order to make the carbon in the ceramic dielectric film amorphous, when a raw material powder, a resin or the like and a solvent are mixed to produce a molded body, the resin is hardly crystalline even when heated. Or a carbohydrate may be added, and the molded body may be degreased in an atmosphere containing less oxygen or a non-oxidizing atmosphere. Alternatively, amorphous carbon may be produced by heating a carbohydrate or resin which is likely to become amorphous by heating sucrose or the like, and then adding it. Further, when crystalline carbon is added, crystalline carbon black or graphite powder obtained by pulverizing graphite may be used. Further, since the acrylic resin binder has a different degree of decomposability depending on the acid value, it is possible to adjust the carbon amount and the crystallinity to some extent by changing the acid value.

The thickness of the ceramic dielectric film is 50 to 50.
It is desirable to be 5000 μm. If the thickness of the ceramic dielectric film is less than 50 μm, a sufficient withstand voltage cannot be obtained because the film thickness is too small, and the dielectric breakdown of the ceramic dielectric film occurs when a silicon wafer is placed and adsorbed. In some cases, the rigidity is low, and the bending of the ceramic substrate cannot be prevented. On the other hand, if the thickness of the ceramic dielectric film exceeds 5000 μm, the distance between the silicon wafer and the electrostatic electrode is increased, and the ability to adsorb the silicon wafer is reduced. The thickness of the ceramic dielectric film is more preferably 50 to 1500 μm.

The porosity of the ceramic dielectric film is preferably 5% or less, and the maximum pore diameter is preferably 50 μm or less. If the porosity exceeds 5%, the number of pores in the ceramic dielectric film increases, and the pore diameter becomes too large. As a result, the pores easily communicate with each other, and the ceramic dielectric having such a structure is used. This is because the withstand voltage of the film decreases. Further, when the pore diameter of the maximum pore exceeds 50 μm, the ratio of the pore diameter to the thickness of the ceramic dielectric film increases, and the proportion of the pores communicating with each other increases, so that the withstand voltage also decreases. Because. The porosity is more preferably 0 or 3% or less, and the pore diameter of the maximum pore is more preferably 0 or 10 μm or less.

The porosity and the maximum pore diameter are adjusted by the pressurizing time, pressure, temperature, and additives such as SiC and BN during sintering. Since SiC and BN hinder sintering, pores can be introduced. For the measurement of the pore diameter of the maximum pore, five samples were prepared, the surface thereof was mirror-polished,
This is performed by photographing the surface at 10 places with an electron microscope at a magnification of 00 times. Then, the maximum pore diameter is selected from the photographed images, and the average of 50 shots is defined as the maximum pore diameter.

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 .

As described above, the reason why the ceramic dielectric film may have a certain amount of pores is that the presence of a certain amount of open pores on the surface of the ceramic dielectric film facilitates the dechucking. Because it can be done.

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.

Examples of the material of the ceramic substrate used in the electrostatic chuck of the first invention include a nitride ceramic, a carbide ceramic, an oxide ceramic and the like. The nitride ceramic, the carbide ceramic,
Examples of the oxide ceramic include those described in the description of the ceramic dielectric film.

Among these ceramics, nitride ceramics and carbide ceramics are desirable. These are because they have high thermal conductivity and can satisfactorily transmit the heat generated by the resistance heating element.

It is desirable that the ceramic dielectric film and the ceramic substrate are made of the same material. In this case, the green sheets produced by the same method are laminated and fired under the same conditions, whereby the green sheets can be easily produced. Also, among nitride ceramics, aluminum nitride is most preferred. This is because the thermal conductivity is the highest at 180 W / m · K.

[0049] The ceramic substrate may contain carbon. Thereby, high radiant heat is obtained. The carbon content is preferably about 5 to 5000 ppm. The carbon may be crystalline such as graphite powder, or may be amorphous formed using a carbohydrate or resin that is likely to be amorphous,
Both crystalline and amorphous may be used.

Further, it is preferable that 0.1 to 20% by weight of a metal oxide is contained in the ceramic such as the nitride ceramic constituting the ceramic substrate as in the case of the ceramic dielectric film. The porosity of the ceramic substrate is preferably 5% or less, and the maximum pore diameter is preferably 50 μm or less. The porosity is more preferably 0 or 3% or less, and the maximum pore size is 0 or 10 μm.
m or less is more preferable.

FIGS. 8 and 9 are horizontal cross-sectional views schematically showing electrostatic electrodes in another electrostatic chuck.
In the electrostatic chuck 20 shown in FIG. 1, 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. Inside are formed chuck positive electrostatic layers 32a and 32b and chuck negative electrostatic layers 33a and 33b each having a shape obtained by dividing a circle into four parts. Also, two positive electrode electrostatic layers 22a and 22b and two chuck negative electrode electrostatic layers 3
3a and 33b are formed to cross each other. An RF electrode may be provided on the electrostatic chuck, and the electrostatic electrodes may be provided on both sides of the ceramic substrate. 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.

In the electrostatic chuck according to the first aspect of the present invention, as shown in FIG. 1, a temperature control means such as a resistance heating element is provided. 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.

When the resistance heating element is embedded in the ceramic substrate, it is desirable to provide the resistance heating element within a range of 60% of the thickness from the bottom surface. This is because heat is diffused before reaching the heating surface, and the temperature of the heating surface tends to be uniform.

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 _TwoO_Three), 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.

It is desirable that the above metal oxide is used in an amount of 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 ratios of lead oxide, zinc oxide, silica, boron oxide (B ₂ O ₃ ), alumina, yttria, and titania are 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 ceramic substrate, no coating is required because the surface of the resistance heating element is not oxidized. When the resistance heating element is formed inside the ceramic substrate, a part of the surface of the resistance heating element may be exposed.

In the case where a ceramic substrate is manufactured by charging a ceramic powder or the like into a mold, forming a molded body, and then firing the molded body, a metal foil or a metal wire is embedded in the molded body to generate resistance heat. A body can be provided. As the metal foil to be used as the resistance heating element, it is desirable to use a nickel foil or a stainless steel foil which is patterned by etching or the like to form a resistance heating element. 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 substrate 82 or the like. As a Peltier element,
For example, a silicon-germanium-based material, a bismuth-antimony-based material, a lead / tellurium-based material, and the like can be given.

As shown in FIG. 1, 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. The electrostatic chuck 101 has a configuration in which the resistance heating element 5 is provided inside the ceramic substrate 1. As shown in FIG. 4, the electrostatic chuck 101 is provided between the ceramic substrate 1 and the ceramic dielectric film 4. An electrostatic chuck 20 having a configuration in which an electric layer 2 and a chuck negative electrode electrostatic layer 3 are provided, and a resistance heating element 15 is provided on the bottom surface of the ceramic substrate 1.
1. As shown in FIG. 5, 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 resistance heating element is provided inside the ceramic substrate 1. An electrostatic chuck 301 having a configuration in which a certain metal wire 7 is embedded, 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. An electrostatic chuck 401 or the like having a configuration in which a Peltier element 8 including a thermoelectric element 81 and a ceramic substrate 82 is formed on the bottom surface of the ceramic substrate 1 is exemplified.

In the first embodiment of the present invention, as shown in FIGS. 1 to 5, the chuck positive electrostatic layer 2 and the chuck negative electrostatic layer 3 are provided between the ceramic substrate 1 and the ceramic dielectric film 4. Since the resistance heating element 5 and the metal wire 7 are formed inside the ceramic substrate 1, connection portions (through holes) 16 and 17 for connecting these and external terminals are required. The through holes 16 and 17 are formed by filling a high melting point metal such as a tungsten paste or a molybdenum paste, or 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 to 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 first aspect of the present invention, a thermocouple can be embedded in the bottomed hole 12 of the ceramic substrate 1 as needed. 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. For this reason, the temperature controllability is improved and the temperature distribution on the heated surface of the wafer is reduced. As the thermocouple,
For example, as described in JIS-C-1602 (1980), K-type, R-type, B-type, S-type, E-type, J-type, and T-type thermocouples can be used.

FIG. 10 is a sectional view schematically showing a support container 41 for disposing the electrostatic chuck of the first aspect of 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. Further, the support container may be configured such that, after placing the ceramic substrate on the upper surface of the support container, the support substrate is fixed with a fixing member such as a bolt. The electrostatic chuck of the first aspect of the present invention can be used at 100 to 800 ° C.

Next, an example of the first method of manufacturing the electrostatic chuck of the present invention will be described with reference to the sectional views shown in FIGS. (1) First, powder of ceramics such as oxide ceramics, oxygen-containing nitride ceramics and carbide ceramics obtained by firing in an oxidizing atmosphere is used as an auxiliary,
Mix with a binder and a solvent to prepare a paste,
This paste is formed into a sheet by a doctor blade method or the like, and a green sheet 50 is produced. As the above-mentioned ceramic powder, for example, aluminum nitride, silicon carbide or the like can be used, and if necessary, a sintering aid such as yttria or carbon may be added.

It is to be noted that several or one green sheet 50 laminated on a green sheet on which a later-described electrostatic electrode layer printed body 51 is formed is a layer to be the ceramic dielectric film 4. Usually, it is desirable to use the same material for the ceramic dielectric film 4 and the material for the ceramic substrate 1. Because these are often sintered together,
This is because suitable 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.

Examples of the binders usually used include acrylic binders, ethyl cellulose, butyl cellosolve,
Examples thereof include polyvinyl alcohol, and at least one selected from these can be used as a binder for forming a ceramic substrate. Further, as the solvent, at least one selected from α-terpineol and glycol is desirable.

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 required. 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 to be 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, tungsten or molybdenum carbide is 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 diameter of the conductive ceramic particles and metal particles is preferably 0.1 to 5 μm. This is because it is difficult to print the conductor paste when these particles 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 paste for a conductor 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 conductor 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 having no printed body is laminated. On the green sheet on which the electrostatic electrode layer printed body 51 is formed, several or one green sheets 5 having the above-described configuration are provided.
0 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. . If baking for forming the resistance heating element is performed with the end face of the through hole exposed, it is necessary to sputter a metal which is hardly oxidized such as nickel. Furthermore, it is preferable to coat with Au-Ni gold solder.

(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.

(7) Finally, as shown in FIG.
External terminals 6 and 18 are provided in the blind holes 13 and 14 via a brazing material such as gold brazing. Further, if necessary, the bottomed hole 12
And a thermocouple can be embedded therein. As the solder, alloys such as silver-lead, lead-tin, and bismuth-tin can be used. The thickness of the solder layer is 0.1 to
50 μm is desirable. 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.
When manufacturing a ceramic substrate having an electrostatic electrode layer, a conductive paste is printed and baked on the bottom surface of the ceramic substrate 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. Further, when manufacturing the electrostatic chuck 301 (see FIG. 5), when a ceramic powder (granules) is charged into a mold or the like to form a molded body, a metal foil or a metal wire is formed by an electrostatic electrode or resistance heating. It may be embedded as a body and sintered. Further, when manufacturing the electrostatic chuck 401 (see FIG. 6), after manufacturing a ceramic substrate having an electrostatic electrode layer, a Peltier element may be joined to the ceramic substrate via a sprayed metal layer or the like.

Next, the electrostatic chuck according to the second embodiment of the present invention will be described. According to a second aspect of the present invention, there is provided an electrostatic chuck in which a temperature control unit is provided on a ceramic substrate, an electrostatic electrode is formed on the ceramic substrate, and a ceramic dielectric film is provided on the electrostatic electrode. The ceramic substrate is an electrostatic chuck having a diameter of more than 300 mm and a thickness of 20 mm or less. 1 to 10 are diagrams schematically showing an example of the second embodiment of the present invention.

The ceramic substrate constituting the electrostatic chuck according to the second aspect of the present invention has a diameter exceeding 300 mm. This is in order to cope with an increase in the size of a silicon wafer and to deal with a next-generation semiconductor wafer.

The ceramic substrate has a thickness of 20 mm or less, preferably 10 mm or less.
This is because, with the enlargement of the electrostatic chuck, the thickness is reduced to reduce the heat capacity thereof. Further, when the diameter of the ceramic substrate is 300 mm or more, the area of the outer periphery becomes large,
The contact area with an atmospheric gas such as air is increased, and the temperature of the outer peripheral portion is significantly reduced. Therefore, the contact area is reduced by reducing the thickness of the ceramic substrate. Thereby, the temperature of the outer peripheral portion is prevented from lowering.

The other components of the electrostatic chuck according to the second embodiment of the present invention, such as the ceramic substrate, the ceramic dielectric film, the resistance heating element, and the thermocouple, are the same as those of the first embodiment of the present invention. Therefore, the description is omitted.

Further, according to the second method of manufacturing the electrostatic chuck of the present invention, the diameter of the ceramic substrate is set to exceed 300 mm, and 0.1 to 20% by weight of oxygen is contained in the ceramic dielectric film. The method is the same as the first method for manufacturing an electrostatic chuck of the present invention except that it is desirable to contain the same, and therefore description thereof will be omitted.

[0091]

The present invention will be described in more detail below. (Example 1) Manufacture of electrostatic chuck (see FIG. 1) (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama, average particle size 1.1 μm), yttria (average particle size:
0.4 μm) 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 is performed by a doctor blade method. Thus, 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, punch 1.8m in diameter
m, a portion serving as a through hole for inserting a lifter pin for a 3.0 mm and 5.0 mm semiconductor wafer, 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 by screen printing.

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 no tungsten paste is printed are laminated on the upper side (heating surface) and 13 green sheets 50 on the lower side, and a conductive paste layer composed of an electrostatic electrode pattern is formed thereon. Are laminated, and one green sheet 50 on which the tungsten paste is not printed is further laminated thereon, and these are pressed at 130 ° C. under a pressure of 80 kg / cm ² to form a laminate. (FIG. 7 (a)).

(4) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 150 ° C.
It was hot-pressed at kg / cm ² for 3 hours to obtain an aluminum nitride plate having a thickness of 3 mm. This was cut out into a 210 mm disk shape, and a plate-like body made of aluminum nitride having therein a 6 μm thick, 10 mm wide resistance heating element 5, a 10 μm thick chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3. (FIG. 7B). The thickness of the ceramic dielectric film was 500 μm.

(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.

Example 2 Production of Electrostatic Chuck (See FIG. 4) (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama, average particle size 1.1 μm), yttria (average particle size:
0.4 μm) 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 is performed by a doctor blade method. hand,
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, punch 1.8m in diameter
m, a portion serving as a through hole for inserting a lifter pin for a 3.0 mm and 5.0 mm semiconductor wafer, 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 through holes for through holes for connecting external terminals. On the green sheet 50 after the above processing, two green sheets 50 on which the tungsten paste is not printed are further laminated on the upper side (heating surface) and 48 on the lower side.
The laminate was formed by pressure bonding at 0 ° C. and a pressure of 80 kg / cm ² .

(4) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 150
It was hot-pressed at kg / cm ² for 3 hours to obtain an aluminum nitride plate having a thickness of 5 mm. This was cut into a 210 mm disc to obtain a plate made of aluminum nitride having a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3 each having a thickness of 15 μm. The thickness of the ceramic dielectric film is
It was 1000 μm.

(5) A mask was placed on the bottom of the plate-like body obtained in (4) above, and a recess (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-shaped body on which the conductor 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 is 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 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, a blind hole for exposing the through hole 16 was 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, and 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.

(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). The support container 41 has a cooling gas 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 Production of Electrostatic Chuck 301 (FIG. 5) (1) Two electrodes having the shape shown in FIG. 8 were formed by punching a 10 μm-thick tungsten foil. 100 parts by weight of the two electrodes and the tungsten wire were treated with aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm),
With 4 parts by weight of yttria (average particle size 0.4 μm)
1890 ° C., pressure 150 in nitrogen gas in a mold
Hot pressing was performed at kg / cm ² for 3 hours to obtain an aluminum nitride plate having a thickness of 10 mm. This is 250mm in diameter
Was cut into a circular shape to obtain a plate-like body. At this time, the thickness of the electrostatic electrode layer was 10 μm. The thickness of the ceramic dielectric film was 2000 μm.

(2) The steps (5) to (7) of Example 1 were performed on the plate-like body to obtain an electrostatic chuck 301.

Example 4 Production of Electrostatic Chuck 401 (FIG. 6) The steps (1) to (5) of Example 2 were carried out to a thickness of 14 m.
After forming an aluminum nitride plate having a thickness of m, nickel was further sprayed on the bottom surface, and then a lead / tellurium-based Peltier element was joined to obtain an electrostatic chuck 401.
The thickness of the ceramic dielectric film was 2500 μm.

Comparative Examples 1 to 5 Electrostatic chucks were manufactured in the same manner as in Examples 1 to 4, except that the thickness of the ceramic substrate was 25 mm. Comparative Example 5 is different from Example 1 in that the diameter of the ceramic substrate is 190 mm and the thickness is 25 mm, but other conditions are the same as in Example 1.

Comparative Example 6 As in Example 1, but 2 parts by weight of yttria (average particle size: 0.4 μm) were added.

Comparative Example 7 As in Example 1, except that the aluminum nitride raw material powder was heated for 3 hours to introduce oxygen.

(Example 5) Electrostatic chuck (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama, average particle size 1.1 μm), yttria (average particle size:
0.4 μm) 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 is performed by a doctor blade method. Thus, 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, punch 1.8m in diameter
m, a portion serving as a through hole for inserting a lifter pin for a 3.0 mm and 5.0 mm semiconductor wafer, 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 by screen printing. 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 no tungsten paste is printed are laminated on the upper side (heating surface) and 13 green sheets 50 on the lower side, and a conductive paste layer composed of an electrostatic electrode pattern is formed thereon. Are laminated, and a green sheet 50 on which no tungsten paste is printed is further laminated on the green sheet 50.
The sheets were laminated and pressed at 130 ° C. under a pressure of 80 kg / cm ² to form a laminate (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 150 ° C.
It was hot-pressed at kg / cm ² for 3 hours to obtain an aluminum nitride plate having a thickness of 3 mm. This was cut out into a 310 mm disk shape, and a plate-like body made of aluminum nitride having a 6 μm thick, 10 mm wide resistance heating element 5, a 10 μm thick chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3 inside. (FIG. 7B). The thickness of the dielectric film is 500 μ
m.

(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.

Example 6 Production of Electrostatic Chuck (See FIG. 4) (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), yttria (average particle size:
0.4 μm) 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 is performed by a doctor blade method. hand,
A green sheet having a thickness of 0.47 mm was obtained.

(2) Next, the green sheet was heated to 80 ° C.
After drying for 5 hours, punch 1.8m in diameter
m, a portion serving as a through hole for inserting a lifter pin for a 3.0 mm and 5.0 mm semiconductor wafer, 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, 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, two green sheets 50 on which the tungsten paste is not printed are further laminated on the upper side (heating surface) and 48 on the lower side.
The laminate was formed by pressure bonding at a pressure of 80 kg / cm ² .

(4) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 150 ° C.
It was hot-pressed at kg / cm ² for 3 hours to obtain an aluminum nitride plate having a thickness of 5 mm. This was cut out into a 330 mm disk to obtain a plate-like body made of aluminum nitride having a 15 μm-thick chuck positive electrode electrostatic layer 2 and a chuck negative electrode electrostatic layer 3 inside. The thickness of the dielectric film is 1000μ
m.

(5) A mask was placed on the bottom surface 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 (each weight ratio is 5/55/10/25/5) is added to 100 parts by weight of silver with respect to 7 parts by weight. 0.5 parts by weight. The silver had a scaly shape with an average particle size of 4.5 μm.

(7) The plate-like body on which the conductor 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 is 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 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, and 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.

(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). The support container 41 has a cooling gas 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 7 Production of Electrostatic Chuck 301 (FIG. 5) (1) Two electrodes having the shape shown in FIG. 8 were formed by punching a 10 μm-thick tungsten foil. 100 parts by weight of the two electrodes and the tungsten wire were treated with aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm),
With 4 parts by weight of yttria (average particle size 0.4 μm)
1890 ° C., pressure 150 in nitrogen gas in a mold
Hot pressing was performed at kg / cm ² for 3 hours to obtain an aluminum nitride plate having a thickness of 10 mm. This is 350mm in diameter
Was cut into a circular shape to obtain a plate-like body. At this time, the thickness of the electrostatic electrode layer was 10 μm. The thickness of the ceramic dielectric film was 2000 μm.

(2) The steps (5) to (7) of Example 1 were performed on the plate-like body to obtain an electrostatic chuck 301.

Example 8 Production of Electrostatic Chuck 401 (FIG. 6) Steps (1) to (5) of Example 6 were performed to
After forming an aluminum nitride plate having a thickness of 18 mm and a thickness of 18 mm, nickel was further sprayed on the bottom surface, and then a lead / tellurium-based Peltier element was joined to obtain an electrostatic chuck 401. The thickness of the ceramic dielectric film was 2500 μm.

Comparative Examples 8 to 11 Electrostatic chucks were produced in the same manner as in Examples 5 to 8, except that the thickness of the ceramic substrate was 25 mm. Note that the thickness of the ceramic dielectric film was 500 μm.

(Comparative Example 12) As Example 1, except that
2 parts by weight of yttria (average particle size: 0.4 μm) was added.

(Comparative Example 13) Same as Example 1, except that
The aluminum nitride raw material powder was heated for 3 hours to introduce oxygen.

(Comparative Example 14) As in Example 1, except that the thickness of the ceramic dielectric film was reduced to 10 μm by polishing.
And

(Comparative Example 15) As in Example 1, except that
The thickness of the ceramic dielectric film was set to 5500 μm.

The electrostatic chucks according to Examples 1 to 8 and Comparative Examples 1 to 15 obtained through the above steps were evaluated by the following indexes. Table 1 shows the results.

Evaluation method (1) Heating time and cooling time of the electrostatic chuck The electrostatic chucks of the examples and comparative examples were energized, and the time required for the electrostatic chuck to rise to 400 ° C. was measured. Further, the time until the temperature naturally decreased to 400 to 50 ° C. was measured. (2) Temperature difference of heating surface In the electrostatic chuck according to the example and the comparative example, 4
Thermoviewer (IR162012-001, manufactured by Nippon Datum Co.)
It was measured in 2). (3) Oxygen Content in Ceramic Dielectric Film A sample sintered under the same conditions as those of the sintered bodies according to the examples and the comparative examples was pulverized in a tungsten mortar, and 0.01 g thereof was crushed.
And a simultaneous oxygen / nitridation analyzer (TC- manufactured by LECO) under the conditions of a sample heating temperature of 2200 ° C and a heating time of 30 seconds.
136). (4) Measurement of Variation of Silicon Wafer Chuck Force The silicon wafer divided into 10 was placed on the electrostatic chuck according to the example and the comparative example, and electricity was supplied to the electrostatic chuck, and the temperature of the electrostatic chuck was raised to 400 ° C. Then, the chucking force of the silicon wafer in each divided section was measured with a load cell, and the average value was calculated. Furthermore, the difference between the maximum chucking force and the minimum chucking force was divided by the average and expressed as a percentage.

[0143]

[Table 1]

As shown in Table 1, the electrostatic chucks according to Examples 1 to 8 reached 400 ° C. in 190 to 950 seconds, whereas the electrostatic chucks according to Comparative Examples 1 to 5 and 8 to 11 In the case of the electric chuck, the time to reach 400 ° C. became longer. In addition, the cooling time was set to 24.5 by setting the thickness to 10 mm or less (Examples 1 to 3 and 5 to 7).
It is shorter than seconds. Further, the temperature difference is optimally 4 ° C. or less when the thickness is 5 mm or less and the oxygen content is 20% by weight or less. It should be noted that there was no problem in the characteristics such as the chucking force of the electrostatic chuck in both the above Examples and Comparative Examples. In the case of a substrate having a diameter of 300 mm or more, the thickness is 25 mm.
If it exceeds mm, the temperature of the outer peripheral portion is significantly reduced. Therefore, by adjusting the thickness to 25 mm or less, variations in temperature and variations in chucking force can be reduced. Further, by adjusting the thickness of the dielectric film and the oxygen content in the dielectric film, it is possible to reduce variations in the temperature of the heating surface and variations in the chucking force.

[0145]

As described above, the first and second electrostatic chucks of the present invention have a small thickness despite the large diameter of the ceramic substrate, so that the heat capacity does not increase. Excellent heating and cooling characteristics. In addition, the entire electrostatic chuck device can be reduced in weight and thickness, which is convenient for transportation and the like, and can save space in operations such as semiconductor manufacturing.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing one example of first and second electrostatic chucks of 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 longitudinal sectional view schematically showing one example of the first and second electrostatic chucks of the present invention.

FIG. 5 is a longitudinal sectional view schematically showing one example of the first and second electrostatic chucks of the present invention.

FIG. 6 is a longitudinal sectional view schematically showing one example of the first and second electrostatic chucks of the present invention.

FIGS. 7A to 7D are longitudinal sectional views schematically showing a part of a manufacturing process of the first and second electrostatic chucks.

FIG. 8 is a horizontal sectional view schematically showing one example of an electrostatic electrode constituting the first and second electrostatic chucks of the present invention.

FIG. 9 is a horizontal sectional view schematically showing one example of an electrostatic electrode constituting the first and second electrostatic chucks of the present invention.

FIG. 10 is a cross-sectional view schematically showing a state in which the first and second electrostatic chucks of the present invention are fixed to a support container.

[Explanation of symbols]

 2, 22, 32a, 32b Chuck positive electrode electrostatic layer 2a, 3a Semicircular portion 2b, 3b Comb portion 3, 23, 33a, 33b Chuck negative electrode electrostatic layer 4 Ceramic dielectric film 5 Resistance heating element 6 External terminal pin Reference Signs List 7 metal wire 8 Peltier element 9 silicon wafer 11 bottomed hole 12 through hole 15 resistance heating element 16, 17 through hole 20, 30, 101 electrostatic chuck 41 support container 42 refrigerant outlet 43 suction port 44 refrigerant injection port 45 heat insulating material 81 thermoelectric element 82 ceramic substrate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C016 GA10 4G001 BA09 BA36 BB09 BB36 BB73 BC35 BC42 BC54 BC72 BC73 BD38 BE31 BE32 5F031 CA02 HA02 HA03 HA10 HA16 HA18 HA37 HA38 JA46 MA28 MA32 PA18 PA30

Claims (6)

[Claims] 1. An electrostatic chuck in which a temperature control means is provided on a ceramic substrate, an electrostatic electrode is formed on the ceramic substrate, and a ceramic dielectric film is provided on the electrostatic electrode. Is an electrostatic chuck having a diameter of more than 190 mm and a thickness of not more than 20 mm, wherein the ceramic dielectric film contains 0.1 to 20% by weight of oxygen. 2. The electrostatic chuck according to claim 1, wherein a resistance heating element is used as said temperature control means. 3. An electrostatic chuck in which a temperature control means is provided on a ceramic substrate, an electrostatic electrode is formed on the ceramic substrate, and a ceramic dielectric film is provided on the electrostatic electrode. Is an electrostatic chuck having a diameter exceeding 300 mm and a thickness of 20 mm or less. 4. The ceramic dielectric film according to claim 1, wherein
4. The electrostatic chuck according to claim 3, which contains -20% by weight of oxygen. 5. The electrostatic chuck according to claim 3, wherein a resistance heating element is used as said temperature control means. 6. The ceramic dielectric film according to claim 5, wherein
The electrostatic chuck according to claim 1, having a thickness of 00 μm.