JP2003249545A - Ceramic substrate for semiconductor manufacturing and inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic substrate which keeps a sufficiently high breakdown voltage, even though the diameter of the maximum pore is 50 μm or smaller, which is larger than conventional ones, possesses increased fracture toughness because it has pores, withstands thermal shocks, and possesses reduced warping at high temperatures. <P>SOLUTION: This ceramic substrate is constituted by forming an electric conductor on the surface of or inside the ceramic substrate, wherein the ceramic substrate is composed of oxygen-containing nitride ceramic, and the diameter of the maximum pore is 50 μm or smaller. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic substrate for a semiconductor manufacturing / inspection apparatus mainly used in the semiconductor industry, and particularly to a silicon wafer which has a high withstand voltage and which is used for electrostatic chucking to adsorb a silicon wafer. The present invention relates to a ceramic substrate which has excellent ability and also has excellent temperature rising / falling characteristics when used as a hot plate (ceramic heater) and a ceramic plate for a wafer prober.

[0002]

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

In the process of manufacturing this semiconductor chip,
A silicon wafer placed on the electrostatic chuck is subjected to various treatments such as etching and CVD to form conductor circuits, elements and the like. At that time, since a corrosive gas is used as a deposition gas, an etching gas, etc., it is necessary to protect the electrostatic electrode layer from corrosion by these gases, and in order to induce an adsorption force. The electrostatic electrode layer is usually covered with a ceramic dielectric film or the like.

[0004]

A nitride ceramic is conventionally used as the ceramic dielectric film, but conventionally, the dielectric film was formed by firing without adding an oxide or the like. Most of the pores formed inside the dielectric film communicated with each other, and there were many open pores. When such pores are present, when the volume resistivity of the dielectric layer decreases at high temperature, electrons are likely to fly through the air in the pores due to the application of voltage, causing a so-called spark, and thus the pore diameter of the maximum pores. There is a problem that it is difficult to keep the withstand voltage of the ceramic dielectric film high unless the value is made smaller.

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

[0006]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that sintering can be advanced by adding an oxide to a nitride ceramic and firing it. , It is newly found that the communicating pores are almost eliminated and the independent pores are formed, and the presence of the oxide at the boundary of the ceramic particles makes it possible to secure the withstand voltage at high temperature even if the pore diameter becomes large. Came to.

That is, the present invention is a ceramic substrate in which a conductor is formed on the surface or inside of the ceramic substrate, wherein the ceramic substrate is made of a non-oxide ceramic containing oxygen and has a pore diameter of maximum pores. Is 5
It is a ceramic substrate for semiconductor manufacturing / inspection equipment, which is characterized by being 0 μm or less.

The non-oxide ceramic is preferably 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 the temperature range of 100 to 700 ° C. The ceramic substrate has a thickness of 25 m
It is preferably m or less 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 semiconductor manufacturing / inspection equipment of the present invention is a ceramic substrate having a conductor formed on the surface or inside thereof, and the ceramic substrate contains a non-oxygen-containing non-conductive material. It is characterized by being made of an oxide ceramic and having a maximum pore diameter of 50 μm or less.

In the ceramic substrate of the present invention, the pores do not exist at all, or when the pores exist, the maximum pore diameter is 50 μm or less. If there are no pores,
The withstand voltage at a high temperature becomes particularly high, and conversely, when pores are present, the fracture toughness value becomes high. Or either the design for this may be determined in consideration of the required properties. The reason why the fracture toughness value increases due to the existence of pores is not clear, but it is presumed that the crack extension 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 the inclusion of oxygen allows the sintering to proceed, the communicating pores are almost eliminated, and independent pores are formed, so that the corrosive gas does not erode the conductor. In addition, the independent pores are less likely to cause electrons to fly in the pores than the continuous ventilation holes. Furthermore, by allowing the oxide to exist at the boundaries of the ceramic particles, it is possible to secure the withstand voltage at high temperature even if the pore size becomes large.

In the ceramic substrate of the present invention, it is necessary that the maximum pore diameter is 50 μm or less. If the maximum pore diameter exceeds 50 μm, 100-700 ° C,
This is because it becomes impossible to secure the withstand voltage characteristics at a high temperature of 200 ° C. or higher. The maximum pore diameter is 10μ.
m or less is desirable. This is because the warp amount becomes small at 100 to 700 ° C., particularly at 200 ° C. or higher.

The porosity and the pore size of the maximum porosity are adjusted by the pressurizing time, pressure and temperature at the time of sintering, but the nitride ceramic is adjusted by additives such as SiC and BN. SiC
The reason is that since BN and BN hinder sintering, pores can be introduced.

The measurement of the pore diameter of the maximum pores is carried out by preparing five samples, mirror-polishing the surfaces thereof, and photographing the surfaces at 10 sites with an electron microscope at a magnification of 2000 to 5000 times. Then, the maximum pore diameter was selected from the photographed photographs, and the average of 50 shots was taken as the maximum pore diameter.

0.05 to 10 is contained in the ceramic substrate.
It is desirable to contain oxygen by weight, particularly preferably 0.1 to 5% by weight. If the amount is less than 0.1% by weight, the withstand voltage may not be secured in some cases, and conversely, if the amount exceeds 5% by weight, the withstand voltage may be lowered due to the deterioration of the high temperature withstand voltage characteristic of the oxide. Because. Further, if the oxygen amount exceeds 5% by weight, the thermal conductivity may decrease, and the temperature rising / falling characteristics may deteriorate.

The ceramic substrate has a porosity of 5
% Or less is desirable. If it exceeds 5%, the number of pores increases, and the pore diameter becomes too large. As a result, the pores are easily communicated with each other and the withstand voltage is reduced. The porosity is measured by the Archimedes method. The sinter is crushed, the crushed product is put in an organic solvent or mercury, the volume is measured, the true specific gravity is calculated from the weight and volume of the crushed product, and the porosity is calculated from the true specific gravity and the apparent specific gravity. .

The above ceramic substrate has a temperature of 100 to 700 ° C.
It is desirable to be used in the temperature range of. This is because the structure of the present invention is particularly advantageous because the withstand voltage decreases in such a temperature range. The ceramic substrate is 1
It is desirable that the amount of warpage at 00 to 700 ° C is small.
This is because the semiconductor wafer can be heated uniformly when the ceramic substrate is used as a heater or an electrostatic chuck. If the amount of warpage is large, the semiconductor wafer does not adhere to the heating surface of the heater, and the semiconductor wafer cannot be heated uniformly. This is because the distance from the surface becomes uneven and the semiconductor wafer cannot be heated uniformly. The amount of warpage (that is, the difference between the amounts of warpage before and after the temperature rise) when the temperature of the ceramic substrate is raised to 100 to 700 ° C. and returned to room temperature (25 ° C.) is preferably 7 μm or less.

The ceramic substrate of the present invention is used for semiconductor manufacturing.
It can be used for inspection, and can be used for an electrostatic chuck, a hot plate (ceramic heater), a ceramic plate for a wafer prober (hereinafter simply referred to as a wafer prober), and the like.

The thickness of the ceramic substrate of the present invention is
It is preferably 50 mm or less, particularly 25 mm or less. Particularly, when the thickness of the ceramic substrate exceeds 25 mm, the heat capacity of the ceramic substrate becomes large, and particularly when the temperature control means is provided to heat and cool, the temperature followability deteriorates due to the large heat capacity. is there. Further, the problem of warpage due to the presence of pores that the ceramic substrate of the present invention solves,
This is because it does not easily occur in a thick ceramic substrate having a thickness exceeding 25 mm. Especially, 5 mm or less is optimal. The thickness is preferably 1 mm or more.

The diameter of the ceramic substrate of the present invention is 200 m.
m or more is desirable. Particularly, it is desirable that it is 12 inches (300 mm) or more. This is because it will become the mainstream of next-generation silicon wafers. Further, the problem of warpage in a high temperature region, which is solved by the present invention, is less likely to occur in a ceramic substrate having a diameter of 200 mm or less.

It is preferable that the ceramic substrate has a plurality of through holes into which lifter pins of a semiconductor wafer are inserted. This is because the presence of the through holes facilitates warping due to the release of strain during processing, especially when the Young's modulus decreases at high temperatures, and the present invention is considered to be the most effective structure.

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

In the ceramic substrate of the present invention, it is desirable to include a sintering aid in the ceramic substrate. As the sintering aid, alkali metal oxides, alkaline earth metal oxides and rare earth oxides can be used, and among these sintering aids, CaO, Y ₂ O ₃ , Na ₂ are particularly preferable.
O, Li ₂ O and Rb ₂ O are preferred. Alternatively, alumina may be used. The content of these is 0.1 to 2
0 wt% is desirable.

In the ceramic substrate of the present invention, it is desirable that the ceramic substrate contains 5-5000 ppm of carbon. By including 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, it is possible to prevent a decrease in volume resistivity at high temperatures, and when crystalline carbon is used, it is possible to prevent a decrease in thermal conductivity at high temperatures. Because. Therefore, depending on the application, both crystalline carbon and amorphous carbon may be used together. The carbon content is more preferably 50 to 2000 ppm.

When carbon is contained in the ceramic substrate, it is desirable that carbon is contained so that the lightness thereof is N6 or less as a value based on the regulation of JIS Z8721. Radiant heat has a brightness of this level,
This is because it has excellent concealing properties. Here, for the lightness N, the ideal lightness of black is 0, and the ideal lightness of white is 10,
Each of the colors is divided into 10 so that the perception of the brightness of the color becomes equal between the brightness of black and the brightness of white.
It is indicated by the symbol N10. The actual lightness is measured by comparing with the 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 placement surface of the ceramic substrate, and the silicon wafer is supported by lifter pins or the like, as shown in FIG. It may be held at a fixed distance from the substrate. FIG.
FIG. 3 is a partially enlarged 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 provided in the through hole 95.
6 is inserted and holds the silicon wafer 99. By moving the lifter pin 96 up and down, the silicon wafer 99 is received from the carrier, the silicon wafer 99 is placed on the ceramic substrate 91, and the silicon wafer 9 is moved.
It can be heated while supporting 9. A heating element 92 is formed on the bottom surface 91a of the ceramic substrate 91, and a metal coating layer 92a is provided on the surface of the heating element 92. Further, a bottomed hole 94 is provided, but a thermocouple is inserted therein. The silicon wafer 99 is heated on the wafer heating surface 91b side. In addition, semiconductor manufacturing of the present invention
When the ceramic substrate for the inspection device is used for the ceramic heater, the semiconductor wafer and the heating surface can be separated from each other. The separation distance is preferably 50 to 5000 μm. Further, the present invention is particularly effective in the case of such separation. This is because the amount of warpage of the ceramic substrate at high temperatures is small and the distance between the semiconductor wafer and the heating surface is uniform.

When the ceramic substrate of the present invention is used as a hot plate (ceramic heater), the conductor is a heating element, which may be a metal layer of about 0.1 to 100 μm, or a heating wire. 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 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 100 ° C. or higher, preferably 200 ° C. or higher.

The present invention will be described below by taking an electrostatic chuck and a wafer prober having a hot plate function as examples.

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 contains a non-oxide ceramic containing oxygen, such as a nitride ceramic or a carbide. It is made of ceramics and has a porosity of 5% or less and a maximum pore diameter of 50 μm or less.
It is composed of independent pores. Therefore,
A gas or the like that lowers the withstand voltage does not penetrate the ceramic dielectric film to corrode the electrostatic electrode, and the withstand voltage of the ceramic dielectric film does not drop even at high temperatures. Further, by setting the thickness of the ceramic dielectric film to be 50 to 5000 μm, sufficient withstand voltage can be secured without lowering the chucking force.

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

In this 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. The 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 comprises a semi-circular arc portion 2a and a comb tooth portion 2b, and the chuck negative electrode electrostatic layer 3 also has a semi-circular 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 so as to face each other so as to intersect the comb teeth 2b and 3b. The negative electrode electrostatic layer 3 has a DC power source +
The side and the-side are connected, and the DC voltage V ₂ is applied.

Further, 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, and the resistance heating element 5 is provided. The external terminal pins 6 are connected and fixed to both ends of each of them, and the voltage V ₁ is applied thereto. Although not shown in FIGS. 1 and 2, on the ceramic substrate 1, as shown in FIG. 3, there is a bottomed hole 11 for inserting a temperature measuring element and a lifter pin for supporting and vertically moving the silicon wafer 9. Through hole 12 for inserting (not shown)
Are formed. The resistance heating element 5 may be formed on the bottom surface of the ceramic substrate.

When the electrostatic chuck 101 is made to function, a DC voltage V ₂ is applied to the chuck positive electrode electrostatic layer 2 and the chuck negative electrode 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, the silicon wafer 9 is subjected to various processes such as CVD.

The electrostatic chuck according to the present invention has a structure as shown in FIGS. In the following, 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 the maximum pore diameter is 50 μm.
It is the following. The thickness is preferably 50 to 1500 μm, and the porosity is preferably 5% or less.

Examples of the above-mentioned nitride ceramics include metal nitride ceramics such as aluminum nitride, silicon nitride, boron nitride and titanium nitride. Among these, aluminum nitride is most preferable. This is because the withstand voltage is high and the thermal conductivity is 180 W / m · K, which is the highest.

The above-mentioned nitride ceramic contains oxygen. Therefore, in the nitride ceramic, sintering easily proceeds, and even when the pores are included, the pores become independent pores, and thus the withstand voltage is improved for the reason described above.

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 the raw material powder of the nitride ceramic is mixed with a metal oxide and fired. To 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. To be The addition amount of these metal oxides is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the nitride ceramic.

The porosity of the ceramic dielectric film is preferably 5% or less. Moreover, the thickness is 50 to 50.
It is desirable that the diameter is 00 μm and the pore diameter of the maximum pore is 50 μm or less. The thickness of the ceramic dielectric film is 5
If it is less than 0 μm, a sufficient withstand voltage cannot be obtained because the film thickness is too thin, and when the silicon wafer is placed and adsorbed, the ceramic dielectric film may cause dielectric breakdown. 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 becomes large, and the ability to adsorb the silicon wafer becomes low. The thickness of the ceramic dielectric film is 100-1500μ
m is more preferred.

When the porosity exceeds 5%, the number of pores increases and the pore diameter becomes too large. As a result,
The pores become easier to communicate with each other. With the ceramic dielectric film having such a structure, the withstand voltage is lowered. further,
When the pore diameter of the maximum pore exceeds 50 μm, the withstand voltage at high temperature cannot be secured even if the oxide is present at the grain boundary. The porosity is 0.001 to 1 when the porosity exists.
3% is more preferable, and the maximum pore diameter is 0.1 to 1
0 μm is more preferable.

Carbon is preferably contained in the ceramic dielectric film in an amount of 50 to 5000 ppm. This is because the electrode pattern provided in the electrostatic chuck can be hidden and high radiant heat can be obtained.
Also, the lower the volume resistivity, the higher the adsorption capacity of the silicon wafer in the low temperature range.

In the electrostatic chuck according to the present invention, the reason why pores may be present in the ceramic dielectric film to some extent is that the fracture toughness value can be increased and the thermal shock resistance is high. 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. The metal foil is also preferably made of the same material as the metal sintered body. This is because these metals are relatively hard to oxidize and have sufficient conductivity as electrodes.
As the conductive ceramic, at least one selected from carbides of tungsten and molybdenum can be used.

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 semi-circular 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. The chuck positive electrode electrostatic layers 32a and 32b and the chuck negative electrode electrostatic layers 33a and 33b, each having a shape obtained by dividing a circle into four, are formed inside. Further, the two positive electrode electrostatic layers 22a and 22b and the two chuck negative electrode electrostatic layers 33a and 33b are formed to intersect with each other. In the case of forming an electrode having a shape in which a circular electrode is divided, the number of divisions is not particularly limited and may be 5 or more, and the shape thereof is not limited to a fan shape.

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

Examples of the above-mentioned nitride ceramics include:
Examples thereof include aluminum nitride, silicon nitride, boron nitride, titanium nitride and the like. Examples of the above-mentioned carbide ceramics include silicon carbide, boron carbide, titanium carbide, tungsten carbide and the like. Further, it is desirable that the ceramic dielectric film and the ceramic substrate are made of the same material. This is because the nitride ceramic has a high thermal conductivity and can satisfactorily transfer the heat generated by the resistance heating element. Further, when the ceramic dielectric film and the ceramic substrate are made of the same material, the electrostatic chuck can be easily manufactured by stacking the green sheets produced by the same method and firing them under the same conditions. . Aluminum nitride is most preferable among the nitride ceramics. This is because the highest thermal conductivity is 180 W / m · K.

Carbon is contained in the above-mentioned ceramic substrate.
It is desirable to contain 0 to 5000 ppm. This is because high radiant heat can be obtained. As the carbon, either crystalline or amorphous that cannot be detected by X-ray diffraction may be used, or both crystalline and amorphous may be used.

In the electrostatic chuck according to the present invention, usually, as shown in FIG. 1, temperature control means such as a resistance heating element is provided. This is because it is necessary to perform the CVD process or the like while heating the silicon wafer placed on the electrostatic chuck or the like.

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 used. The resistance heating element may be provided inside the ceramic substrate or on the bottom surface of the ceramic substrate. When the resistance heating element is provided, a support container into which the electrostatic chuck is fitted may be provided with a blowing port for a cooling medium such as air as a cooling means.

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 the pattern is formed in any of the layers as viewed from the heating surface. For example, a structure in which staggered arrangement is provided.

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

As the conductive ceramic, at least one selected from carbides of tungsten and molybdenum is used.
Seeds can be used. Further, when the 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, flaky, or a mixture of spherical and flaky.

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

Examples of the above metal oxide include, for example, oxidation.
Lead, zinc oxide, silica, boron oxide (B _TwoO_Three), Al
At least one selected from Mina, Yttria, and Titania
Seeds are preferred. These oxides are the resistance value of the resistance heating element.
Between the metal particles and the ceramic substrate without increasing the
This is because the adhesion can be improved.

The amount of the above metal oxide is preferably 0.1 part by weight or more and less than 10 parts by weight with respect to 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 proportion 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, lead oxide is 1 to 1. 10 parts by weight, 1 to 30 parts by weight of silica, 5 to 50 parts by weight of boron oxide, 20 to 7 of zinc oxide.
0 parts by weight, alumina 1 to 10 parts by weight, yttria 1
-50 parts by weight and titania 1-50 parts by weight are preferred.
However, it is desirable that the total amount of these components be adjusted within a range not exceeding 100 parts by weight. This is because these ranges can 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 the metal layer 150 (see FIG. 4). The resistance heating element 15 is a sintered body of metal particles, and if exposed, it is easily oxidized, and the resistance value changes due to this oxidation. Therefore, by covering the surface with the metal layer 150, oxidation can be prevented.

The metal layer 150 has a thickness of 0.1 to 10 μm.
Is desirable. This is because the resistance heating element can be prevented from being oxidized 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 preferable.
Of these, nickel is more preferable. This is because the resistance heating element needs a terminal for connecting to a power supply, and this terminal is attached to the resistance heating element via solder, but nickel prevents heat diffusion of the solder. A terminal pin made by Kovar can be used as the connection terminal.

When the resistance heating element is formed inside the heater plate, the surface of the resistance heating element is not oxidized, so that no coating is required. 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 foil as a resistance heating element by patterning by etching or the like. The patterned metal foil may be laminated 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 a p-type or n-type thermoelectric element 81.
Are connected in series and are joined to the ceramic plate 82 or the like. Examples of the Peltier element include silicon / germanium-based materials, bismuth / antimony-based materials, lead / tellurium-based materials, and the like.

As an electrostatic chuck according to the present invention, for example, as shown in FIG. 1, 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. An electrostatic chuck 101 having a structure in which a resistance heating element 5 is provided inside the ceramic substrate 1,
As shown in FIG. 4, 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 15 is provided on the bottom surface of the ceramic substrate 1. Of the electrostatic chuck 201 having the above configuration, FIG.
As shown in FIG. 3, a chuck positive electrode electrostatic layer 2 and a chuck negative electrode electrostatic layer 3 are provided between the ceramic substrate 1 and the ceramic dielectric film 4, and a metal wire 7 as a resistance heating element is provided inside the ceramic substrate 1. Electrostatic chuck 30 having a structure in which
As shown in FIG. 1 and FIG. 6, 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 thermoelectric element 81 is provided on the bottom surface of the ceramic substrate 1. Peltier element 8 consisting of ceramic plate 82
An electrostatic chuck 401 or the like having a structure in which is formed.

The electrostatic chuck according to the present invention is shown in FIGS.
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 wire are provided inside the ceramic substrate 1. 7 are formed, connection portions (through holes) 16 and 1 for connecting these and external terminals are formed.
7 is required. The through holes 16 and 17 are made of a refractory metal such as tungsten paste or molybdenum paste.
It is formed by filling a conductive ceramic such as tungsten carbide or molybdenum carbide.

Further, the connecting portions (through holes) 16 and 17
The diameter is preferably 0.1 to 10 mm. This is because it is possible to prevent cracks and distortions while preventing disconnection. The external terminal pins 6 and 18 are connected using the through holes as connection pads (see FIG. 7D).

Connection is made with solder or brazing material. As a brazing material, silver brazing, palladium brazing, aluminum brazing,
Use gold wax. Au-Ni alloy is preferable for gold brazing. This is because the Au-Ni alloy has excellent adhesion to tungsten.

The Au / Ni ratio is [81.5 to 82.
5 (wt%)] / [18.5 to 17.5 (wt%)] is desirable. The thickness of the Au—Ni layer is preferably 0.1 to 50 μm. This is because the range is sufficient to secure the connection.
In addition, 500 to 10 at a high vacuum of 10 ⁻⁶ to 10 ⁻⁵ Pa.
When used at a high temperature of 00 ° C., the Au—Cu alloy deteriorates, but the Au—Ni alloy is advantageous because it does not deteriorate. The total amount of impurity elements in the Au-Ni alloy is 1
When the amount is 00 parts by weight, it is preferably 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 if necessary. This is because the temperature of the resistance heating element can be measured with a thermocouple and the temperature can be controlled by changing the amount of voltage and current based on the data. The size of the joining portion of the metal wire of the thermocouple is equal to or larger than the wire diameter of each metal wire, and is preferably 0.5 mm or less. With such a configuration, the heat capacity of the joint portion is reduced, and the temperature is converted into a current value accurately and quickly. Therefore, the temperature controllability is improved and the temperature distribution on the heating surface of the semiconductor wafer is reduced. Examples of the thermocouple include JIS-C-1602 (198).
0), K type, R type, B type, S type, E
Type, J type, and T type thermocouples.

FIG. 10 is a sectional view schematically showing a support container 41 for disposing the electrostatic chuck according to the present invention having the above structure. The electrostatic chuck 101 is fitted into the support container 41 via a heat insulating material 45. In addition, a refrigerant outlet 42 is formed in the support container 11, and the refrigerant is blown from the refrigerant inlet 44, passes through the refrigerant outlet 42, and exits from the suction port 43. By the action of this coolant, the electrostatic chuck 101 can be cooled.

Next, an example of a method of manufacturing the 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 above-mentioned ceramic powder, 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 sheets 50 'to be laminated on the green sheet on which the electrostatic electrode layer printed body 51 to be described later is formed are layers to be the ceramic dielectric film 4, the nitriding is performed. It is assumed that the powder of the product is mixed with the powder of the oxide. Usually, it is desirable to use the same material for the ceramic dielectric film 4 and the ceramic substrate 1. This is because these are often sintered as one body, and the firing conditions are the same. However, when the materials are different, the ceramic substrate may be manufactured first, the electrostatic electrode layer may be formed thereon, and the ceramic dielectric film may be further formed thereon.

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

If necessary, the green sheet 50 may be provided with through holes for inserting the lifter pins of the silicon wafer and recesses for embedding the thermocouple. The through holes and the recesses can be formed by punching or the like. The thickness of the green sheet 50 is preferably about 0.1 to 5 mm.

Next, the green sheet 50 is printed with a conductive paste that will serve as an electrostatic electrode layer and a resistance heating element. The printing is performed so that a desired aspect ratio is obtained in consideration of the shrinkage rate of the green sheet 50, whereby the electrostatic electrode layer printed body 51 and the resistance heating element layer printed body 52 are obtained. The printed body is formed by printing a conductive paste containing conductive ceramics, metal particles and the like.

Carbide of tungsten or molybdenum is most suitable as the conductive ceramic particles contained in these conductor pastes. This is because it is difficult to oxidize and the thermal conductivity does not easily decrease. Further, as the metal particles, for example, tungsten, molybdenum, platinum, nickel or the like can be used.

The average particle diameter of the conductive ceramic particles and the 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. Examples of such paste include 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 printed bodies 53 and 54.

Next, as shown in FIG. 7A, the printed body 5
A green sheet 50 having 1, 52, 53, 54;
The green sheet 50 'is laminated. The green sheet 50 'having no printed body is laminated on the resistance heating element formation side in order to prevent the end surface of the through hole from being exposed and being oxidized during firing of the resistance heating element formation. is there.
If firing is performed to form the resistance heating element with the end face of the through hole exposed, it is necessary to sputter a metal that is difficult to oxidize, such as nickel, and more preferably, coat with Au—Ni gold brazing. Good.

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

(3) Next, as shown in FIG. 7C, bag 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 is made conductive, and the conductive inner walls are connected to the chuck positive electrode electrostatic layer 2, the chuck negative electrode electrostatic layer 3, the resistance heating element 5, and the like. desirable.

(4) Finally, as shown in FIG. 7 (d),
External terminals 6 and 18 are provided in the bag holes 13 and 14 through a brazing filler metal. Further, a bottomed hole 11 may be provided and a thermocouple may be embedded inside the hole 11 if necessary. Solder is silver-lead,
Alloys such as lead-tin, bismuth-tin can be used. The thickness of the solder layer is preferably 0.1 to 50 μm. This is because the range is sufficient to secure the connection with solder.

In the above description, the electrostatic chuck 101
(See FIG. 1) as an example, the electrostatic chuck 201 (see FIG.
In the case of manufacturing), after manufacturing a ceramic plate having an electrostatic electrode layer, a conductor paste is printed and fired on the bottom surface of the ceramic plate to form a resistance heating element 15, and then electroless plating or the like. The metal layer 150 may be formed by. Further, 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, in the case of manufacturing the electrostatic chuck 401 (see FIG. 6), after manufacturing a ceramic plate having an electrostatic electrode layer, a Peltier element may be bonded 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 the conductor inside is at least one of a guard electrode and a ground electrode, the ceramic substrate is a wafer prober. Function as.

FIG. 11 is a sectional view schematically showing an embodiment of the wafer prober according to the present invention, and FIG.
FIG. 12 is a sectional view taken along the line AA of the wafer prober shown in FIG. 11. In this wafer prober 601, grooves 6 each having a concentric circular shape in plan view are formed on the surface of a ceramic substrate 63 having a circular shape in plan view.
7 is formed, 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 the electrode of the silicon wafer. The chuck top conductor layer 62 is formed in a circular shape.

On the other hand, on the bottom surface of the ceramic substrate 63, in order to control the temperature of the silicon wafer, there are provided heating elements 69 having a concentric circular shape in plan view as shown in FIG. Has external terminal pins (not shown) connected and fixed. Also, the ceramic substrate 6
A guard electrode 65 and a ground electrode 66 (see FIG. 7) having a lattice shape in plan view are provided inside the unit 3 in order to remove stray capacitors and noise. Guard electrode 65
The material of the ground electrode 66 and 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. This is because if it is less than 1 μm, the resistance value becomes too high to function as an electrode, and if it exceeds 20 μm, peeling easily occurs due to the stress of the conductor.

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

In the wafer prober having such a structure, after mounting a silicon wafer having an integrated circuit formed thereon, a probe card having tester pins is pressed against this silicon wafer, and a voltage is applied while heating and cooling. Continuity test can be performed. In the case of manufacturing a wafer prober, for example, as in 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. Then, the metal layer may be formed by performing sputtering, plating or the like on 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 calcined 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: 0.4μ
m) Using a paste prepared 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 an alcohol consisting of 1-butanol and ethanol, a doctor blade method was used to perform molding. Thickness 0.
A 47 mm green sheet was obtained.

(2) Next, this green sheet is heated to 80 ° C.
1.8m in diameter after punching after drying for 5 hours.
m, 3.0 mm, and 5.0 mm semiconductor wafers were provided with portions to be through holes for inserting lifter pins and portions to be through holes for connecting to external terminals.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm and an acrylic binder of 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 conductor 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 part 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 having an electrostatic electrode pattern having the shape shown in FIG. 2 was formed on another green sheet.

Further, the conductor paste B was filled in the through holes for through holes for connecting the external terminals. 34 green sheets 50 'on which the conductor paste A is not printed are laminated on the upper side (heating surface) and 13 layers on the lower side of the green sheet 50 which has been subjected to the above-mentioned treatment, and a conductor including an electrostatic electrode pattern is formed on the green sheet 50'. A green sheet 50 on which a paste layer is printed is laminated, two green sheets 50 'on which a tungsten paste is not printed are further laminated thereon, and these are pressure-bonded at 130 ° C. and a pressure of 80 kg / cm ² to obtain a laminated body. Was formed (FIG. 7A).

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

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

(6) Further, the portions where the through holes are formed are cut out to form the bag holes 13 and 14 (see FIG. 7).
(C)), Ni braze alloy made of Ni-Au was used for the bag holes 13 and 14, and reflowed by heating at 700 ° C. to connect the external terminals 6 and 18 made of Kovar (FIG. 7D). In addition,
The connection of the external terminal is preferably a structure in which the tungsten support supports at three points. This is because connection reliability can be secured.

(7) Next, a plurality of thermocouples for temperature control were embedded in the bottomed holes to complete the manufacture of the electrostatic chuck having the resistance heating element. The porosity, the pore diameter, the withstand voltage, the fracture toughness value, the adsorption force, the temperature rising characteristic, and the warp amount of the electrostatic chuck having the resistance heating element manufactured in this manner 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 firing time of the aluminum nitride powder, and the value is 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 electrostatic chuck (see FIG. 4) (1) Aluminum nitride powder calcined in air at 500 ° C. for 0, 1 and 7 hours (manufactured by Tokuyama Corp., average particle size) 1.1μ
m) 100 parts by weight, yttria (average particle size: 0.4μ
m) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 parts by weight, BN 0, 3, 5% by weight (details in Table 3) and alcohol 53 parts by weight consisting of 1-butanol and ethanol. By using the mixed paste of (1) and (2), a doctor blade method was performed to obtain a green sheet having a thickness of 0.47 mm.

(2) Next, this green sheet is heated to 80 ° C.
1.8m in diameter after punching after drying for 5 hours.
m, 3.0 mm, and 5.0 mm semiconductor wafers were provided with portions to be through holes for inserting lifter pins and portions to be through holes for connecting to external terminals.

(3) 100 parts by weight of tungsten carbide particles having an average particle diameter of 1 μm and an acrylic binder of 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 conductor 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 part by weight of a dispersant. This conductor paste A was printed on a green sheet by screen printing to form a conductor paste layer having an electrostatic electrode pattern having the shape shown in FIG.

Further, the conductor paste B was filled in the through holes for through holes for connecting the external terminals. On top of the green sheet that has undergone the above treatment, a green sheet on which the conductor paste A is not printed is placed on the upper side (heating surface).
48 sheets are laminated on the lower side and 130 ° C, 80 kg
A pressure was applied at a pressure of / cm ² to form a laminate.

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

(5) A mask was placed on the bottom surface of the plate obtained in (4) above, and a recess (not shown) for a thermocouple or the like 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. The conductor paste was used for printing. The conductor paste used was Solvest PS603D manufactured by Tokuriki Kagaku Kenkyusho, which is used for forming through holes in printed wiring boards. This conductor paste is
It is a silver / lead paste and contains 7 parts by weight of a metal oxide composed of lead oxide, zinc oxide, silica, boron oxide, and alumina (each weight ratio is 5/55/10/25/5). It contained 0.5 parts by weight. Further, the silver had a scaly shape with an average particle size of 4.5 μm.

(7) The plate-shaped body printed with the conductor paste is
By heating and firing at 80 ° C., silver and lead in the conductor paste were sintered and baked on the ceramic substrate. Further, the plate-shaped body is dipped in an electroless nickel plating bath made of 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 is immersed. Then, a nickel layer 150 having a thickness of 1 μm and a boron content of 1% by weight or less was deposited.
Then, the plate-shaped body was subjected to an annealing treatment at 120 ° C. for 3 hours. The resistance heating element made of a silver sintered body has a thickness of 5
μm, width 2.4 mm, area resistivity 7.7 mΩ /
It was □.

(8) Next, a blind hole for exposing the through hole 16 was provided in the ceramic substrate. N in this bag hole
Using a gold braze made of an i-Au alloy (Au 81.5% by weight, Ni 18.4% by weight, impurities 0.1% by weight), 97
Reflowing was performed by heating at 0 ° C. and external terminal pins made of Kovar were connected. Further, 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 embedded in the recess to obtain the electrostatic chuck 201. The porosity, the pore diameter, the withstand voltage, the fracture toughness value, the adsorption force, the temperature rising characteristic, and the warp amount of the electrostatic chuck having the resistance heating element manufactured in this manner 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 firing time of the aluminum nitride powder, and the value is shown in Table 3.

(10) Next, the electrostatic chuck 201 is attached to the stainless steel support container 41 having the cross-sectional shape shown in FIG.
It was fitted in via a heat insulating material 45 made of ceramic fiber (trade name: Ibiwool, manufactured by Ibiden Co., Ltd.). This support container 41 has a coolant 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 the refrigerant into the support container, but it was extremely excellent. The 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 stamping a tungsten foil having a thickness of 10 μm. did. Two electrodes and tungsten wire in air at 500 ℃, 0,
Alumina 0, 1.5, 3.5, together with 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corp., average particle size 1.1 μm) and 4 parts by weight of yttria (average particle size 0.4 μm), which were calcined for 1 to 7 hours. 15% by weight was put in a molding die, and at 1890 ° C. in nitrogen gas, the pressure was 0 to 150 kg / cm.
² (Details in Table 5) Hot pressed for 3 hours, thickness 3mm
To obtain an aluminum nitride plate. This is 230m in diameter
A circular plate of m was cut out to obtain a plate-shaped body. At this time, the thickness of the electrostatic electrode layer was 10 μm.

(2) The steps (5) to (7) of Example 1 were carried out on this plate-like body to obtain the electrostatic chuck 301. The porosity, the pore diameter, the withstand voltage, the fracture toughness value, the adsorption force, the temperature rising characteristic, and the warp amount of the electrostatic chuck having the resistance heating element manufactured in this manner 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 firing time of the aluminum nitride powder.
Is shown in.

[0110]Evaluation methods (1) Oxygen amount Samples sintered under the same conditions as the sintered body according to the example
Grind in a Gusten mortar and sample 0.01 g of this
Oxygen under the conditions that the material heating temperature is 2200 ° C and the heating time is 30 seconds.
Nitrogen simultaneous analyzer (TC-136 type made by LECO)
It was measured. (2) Measurement of porosity of ceramic dielectric film Cut out the ceramic dielectric film and use the Amikimedes method.
Then, the porosity was measured. Specifically, the cut out sample
Crush into powder and put in organic solvent or mercury for volume
The true specific gravity from the weight of the powder measured in advance.
The porosity was calculated from the measured specific gravity and the apparent specific gravity.

(3) Measurement of Pore Diameter of Ceramic Dielectric Film The electrostatic chuck was cut at several positions in the vertical 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 Regarding the electrostatic chucks manufactured in Examples 1 to 3 and Comparative Examples 1 to 3, a metal electrode was placed on the electrostatic chuck to form an electrostatic electrode layer and an electrode. A voltage was applied during this period 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 meter (MVK-D type manufactured by Akashi Seisakusho Co., Ltd.), the length of cracks generated was measured, and this was substituted into the following formula.

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

(6) Adsorption force load cell (Autograph AGS-5 manufactured by Shimadzu Corporation)
0A).

(7) Temperature rising characteristics The time required to raise the temperature to 450 ° C. was measured. (8) Warpage amount The temperature was raised to 450 ° C., a load of 150 kg / cm ² was applied, the temperature was cooled to 25 ° C., and the amount of warpage was measured using a shape measuring instrument (Nanoway manufactured by Kyocera Corp.).

[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 of 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 at 450 ° C. mm is good. Further, when it has pores, the fracture toughness value can be secured to be 3.5 MPam ^1/2 or more. Further, by setting the pore diameter of the maximum pores to 50 μm or less, the amount of warpage at high temperature can be reduced.
When there are no pores, the withstand voltage becomes very high, and the warp can be almost completely eliminated.

Example 4 The electrostatic chuck 401 (see FIG. 6)
Process) (1) to (5) of manufacturing example 2 (see the conditions of the first stage of Table 3).
After performing the above, the bottom surface was further sprayed with nickel, and thereafter, a lead / tellurium Peltier element was joined to obtain an electrostatic chuck 401. The electrostatic chuck thus manufactured had excellent temperature lowering characteristics, and when cooled by a Peltier device, the temperature was lowered from 450 ° C. to 100 ° C. in 3 minutes.

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

(2) Next, this green sheet is heated to 80 ° C.
After drying for 5 hours, a through hole for 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 and an acrylic binder of 3.0
Parts 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. 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 conductor paste B.

Next, a grid-shaped guard electrode print body and a ground electrode print body were printed on the green sheet by screen printing using the conductor paste A. Further, the conductor paste B was filled in the through holes for through holes for connecting to the terminal pins.

Further, 50 printed green sheets and unprinted green sheets are laminated to form 1
A laminated body was produced by integrating at 30 ° C. and a pressure of 80 kg / cm ² .

(4) Next, this laminated body was subjected to 6 in nitrogen gas.
Degreasing at 00 ℃ for 5 hours, 1890 ℃, pressure 150kg /
It was hot-pressed at cm ² for 3 hours to obtain an aluminum nitride plate-shaped body having a thickness of 3 mm. The plate-shaped body thus obtained has a diameter of 300.
A circular plate of mm was cut out to obtain a ceramic plate-like body. The size of the through hole 660 is 0.2 mm in diameter,
The depth was 0.2 mm.

In addition, the guard electrode 65 and the ground electrode 66
Has a thickness of 10 μm, the guard electrode 65 is formed at a position 1 mm from the wafer mounting surface, and the ground electrode 66 is formed at a position
It was 1.2 mm from the wafer mounting surface. In addition, the conductor non-formed region 66a of the guard electrode 65 and the ground electrode 66
The size of one side was 0.5 mm.

(5) After polishing the plate-like body obtained in (4) above with a diamond grindstone, a mask is placed, and a blast treatment with SiC or the like is performed to form a concave portion for a thermocouple and a wafer adsorption portion on the surface. Groove 67 (width 0.5 mm, depth 0.5 mm)
Was set up.

(6) Further, a layer for forming the heating element 69 is printed on the surface facing the wafer mounting surface. The conductor paste was used for printing. The conductor paste used was Solvest PS603D manufactured by Tokuriki Kagaku Kenkyusho, which is used for forming through holes in printed wiring boards. 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 added to silver 10.
The content was 7.5 parts by weight with respect to 0 parts by weight. Further, 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 bake it 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 dipped in an electroless nickel plating bath made of an aqueous solution containing nickel to form a nickel layer (not shown) having a thickness of 1 μm and a boron content of 1% by weight or less on the surface of the silver sintered body 69.
Was deposited. Then, 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 an area resistivity of 7.7 mΩ / □.

(8) A titanium layer, a molybdenum layer and a nickel layer were sequentially formed on the surface where the groove 67 was formed by a sputtering method. As an apparatus for sputtering, SV-4540 manufactured by Nippon Vacuum Technology Co., Ltd. was used. The sputtering conditions are atmospheric pressure of 0.6 Pa, temperature of 100 ° C. and electric power of 2
The sputtering time was 00 W, and the sputtering time was adjusted depending on each metal within the range of 30 seconds to 1 minute. The thickness of the obtained film was 0.3 μm for the titanium layer from the image of the fluorescent X-ray analyzer.
m, the molybdenum layer was 2 μm, and the nickel layer was 1 μm.

(9) Nickel sulfate 30 g / l, boric acid 3
The surface of the metal layer formed by sputtering by immersing the ceramic plate obtained in (8) above in an electroless nickel plating bath consisting of an aqueous solution containing 0 g / l, ammonium chloride 30 g / l and Rochelle salt 60 g / l 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 carry an electric current and is not covered with electrolytic nickel plating.

Further, on the surface, 2 g of potassium gold cyanide /
1, ammonium chloride 75 g / l, sodium citrate 50 g / l, and sodium hypophosphite 10 g / l 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 is formed in the groove 67 to the rear surface by drilling, and a bag hole (not shown) for exposing the through hole 660 is provided.
Ni-Au alloy (Au 81.5% by weight, Ni
Using a gold braze composed of 18.4% by weight and 0.1% by weight of impurities, reflow was performed by heating at 970 ° C. and external terminal pins made of Kovar were connected. In addition, solder (tin 90
Wt% / 10 wt% lead) to form external terminal pins made of Kovar.

(11) Next, a plurality of thermocouples for temperature control were embedded in the recess 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%. Also, raise the temperature of the ceramic substrate to 200 ° C and increase the voltage to 2
Dielectric breakdown did not occur even when 00V was applied. Further, the amount of warpage was 1 μm or less, which was good.

(Example 6 and Comparative Example 4) 50 in air
100 parts by weight of silicon carbide powder (average particle size: 1.1 μm, manufactured by Yakushima Denko), which was calcined at 0 ° C. for 0, 1, 7 hours, carbon 4
Parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.
Using a paste prepared by mixing 5 parts by weight and 53 parts by weight of alcohol consisting of 1-butanol and ethanol, the paste was molded by the doctor blade method to obtain a green sheet having a thickness of 0.5 mm.

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

The porosity, the pore diameter, the withstand voltage, the fracture toughness value, the adsorption force, the temperature rising characteristic, and the warp amount of the electrostatic chuck having the resistance heating element manufactured as described above 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 firing time of the aluminum nitride powder, and the value is 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 to 8 above, in the electrostatic chuck according to Example 6, the dielectric strength of the ceramic dielectric film is good. Also, the fracture toughness value is 4.0 MPam.
More than ^1/2 can be secured. Further, by setting the pore diameter of the maximum pores to 50 μm or less, the amount of warpage at high temperature can be reduced.

Example 7 and Comparative Example 5 A recess is formed by drilling on the surface of the electrostatic chuck of Example 1 and Comparative Example 1, and a support pin made of alumina for supporting a silicon wafer in this recess. Was formed, and the distance between the silicon wafer and the surface was set to be 100 μm. Next, without applying to the electrostatic electrode, only the resistance heating element was energized 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 warp amount of the ceramic substrate is 1
In the case of 0 μm, the surface temperature difference of the silicon wafer is 3 ° C., but when the warp amount is 8 μm, the temperature difference of the surface of the silicon wafer becomes 10 ° C., and the temperature uniformity of the silicon wafer is poor. It was

(Test Example) As in Comparative Example 1, the aluminum nitride powder was not fired in air but was sintered under normal pressure.
An electrostatic chuck having a thickness of 30 mm was manufactured. In addition, the aluminum nitride powder was not fired in air, and an electrostatic chuck having a diameter of 150 mm was manufactured by pressureless sintering. Both are 45
Even after the temperature was raised to 0 ° C., the warpage amount was 1 μm or less.
That is, in the 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. An electrostatic chuck having no through hole formed was manufactured, but the amount of warp after heating to 450 ° C. was 1 μm or less. As described above, the present invention has a thickness of 25 m.
It is considered that the ceramic substrate for a semiconductor manufacturing / inspection device having a through hole of m or less, a diameter of 200 mm or more, and a through hole is particularly effective.

[0148]

As described above, in 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, which is larger than the conventional one, the withstand voltage is increased. Can be kept large enough. Further, 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 drawings]

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

2 is a cross-sectional view of the electrostatic chuck shown in FIG. 1 taken along the line AA.

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

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

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

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

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

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

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

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

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

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

FIG. 13 is a 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 electrostatic layer 3, 23, 33a, 33b Chuck negative electrode electrostatic layer 2a, 3a semi-circular part 2b, 3b comb teeth 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 holes 13, 14 blind holes 15 Resistance heating element 150 metal layers 16,17 through hole 41 Support container 42 Refrigerant outlet 43 Inhalation port 44 Refrigerant inlet 45 thermal insulation

Continued front page    F term (reference) 3K034 AA02 AA10 BB06 BB14                 3K092 PP20 QA05 RF03 RF11 RF19                       RF22 RF27 VV31 VV34 VV40                 5F031 CA02 HA02 HA16 HA17 HA18                       HA33 HA37 HA38 MA28 MA33                       PA18

Claims (8)

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