JP2001319967A - Method for manufacturing ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic substrate which can relatively facilitate a cutting processing, etc., of a sintered body can cut it in a short time, can reduce the manufacturing cost, and can readily take out the sintered body from a crucible. SOLUTION: In a method for manufacturing a ceramic substrate which is provided with a conductor layer on its surface or in its interior, and is circular or elliptic in plan view, the method comprises the steps of: manufacturing a non-sintered polygonal body; manufacturing a sintered body by sintering the polygonal body to manufacture a polygonal sheet-like sintered body; and performing a cutting processing by cutting the sheet-like sintered body to manufacture the circular or elliptic ceramic substrate in plan view.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic substrate constituting a ceramic heater, an electrostatic chuck, a wafer prober and the like mainly used in the semiconductor industry.

[0002]

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

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

Conventionally, nitride ceramics have been used as this ceramic dielectric film.
JP-8140 discloses an electrostatic chuck using a nitride such as aluminum nitride. Japanese Patent Application Laid-Open No. 9-48668 discloses a carbon-containing aluminum nitride having an Al-ON structure. Also,
The manufacturing method of such an electrostatic chuck is disclosed in Japanese Patent Publication No. 6-9767.
No. 7, for example. Such a ceramic electrostatic chuck is manufactured by a so-called green sheet method as described in JP-A-62-264638 and JP-A-60-261377.

FIGS. 17A to 17D are cross-sectional views schematically showing one example of a conventional method for manufacturing an electrostatic chuck by a green sheet method. (1) First, a slurry is prepared by mixing a ceramic raw material powder such as a nitride ceramic and a carbide ceramic with a sintering aid powder, a binder, a solvent, and the like, and then using this slurry by a doctor blade method or the like. A sheet-like green sheet 50 is produced.

[0006] The green sheet is usually rectangular, since a continuously formed sheet is appropriately cut by a cutter. After drying this green sheet and forming a through hole or the like in a portion to be a through hole or the like, printing is performed using a conductive paste containing a metal or the like on the surface thereof,
Paste layer 51 for electrostatic electrode or paste layer 5 for resistance heating element
Form 2 and so on. In addition, a conductive paste is filled into the through holes and the like. Thereafter, the green sheets are dried.

Next, one or more green sheets on which the conductor paste is not printed are placed above and below the green sheet on which the resistive heating element paste layer 52 is formed and the green sheet on which the electrostatic electrode paste layer 51 is formed. A plurality of sheets are appropriately laminated to form a green sheet laminate (see FIG. 17A).

Next, this green sheet laminate is usually put into a firing crucible or the like and, if necessary, is fired while applying pressure from above and below to obtain a sintered body made of a rectangular plate-like body in plan view. (Plate-shaped sintered body) is manufactured, and then, the rectangular plate-shaped sintered body is subjected to a cutting process to produce a circular ceramic substrate (see FIG. 17B).

Thereafter, a blind hole or the like is formed by using a sand blast method or the like so that the through holes 16 and 17 are exposed (FIG. 17C). Thereafter, external terminals are formed in the blind holes 16 and 17. The manufacture of the ceramic substrate 1 constituting the electrostatic chuck is completed by brazing 6, 18, etc., using a brazing material or the like (FIG. 17D).

[0010]

However, in such a method for manufacturing an electrostatic chuck, since the manufactured sintered body is a rectangular plate-shaped body, it is cut into a circular shape by cutting. It must be, not only takes time to cut, but also the consumption of tools for processing is severe,
There was a problem that manufacturing cost was high. In the case of sintering, the unsintered body is put into the crucible via a mold release agent. However, if it is formed into a disk shape from the beginning, the release agent layer between the crucible wall surface and the unsintered body There is a problem that the sintered body cannot be taken out from the crucible because the wall surface and the sintered body are adhered to each other at the portion where the release agent layer is thin. These are common problems not only in the above-mentioned electrostatic chuck but also in the manufacture of a ceramic substrate constituting a ceramic heater or a wafer prober.

[0011] The present invention has been made to solve the above-mentioned problems, and it is easy to take out a sintered body from a mold.
It is an object of the present invention to provide a method of manufacturing a ceramic substrate for various semiconductor manufacturing apparatuses, in which cutting of a sintered body is relatively easy, cutting can be performed in a short time, and manufacturing cost can be reduced. Aim.

[0012]

SUMMARY OF THE INVENTION A first aspect of the present invention is a method for manufacturing a circular or elliptical ceramic substrate in a plan view having a conductor layer provided on the surface or inside thereof. And baking the polygonal body,
Including a sintered body manufacturing step of manufacturing a polygonal plate-shaped sintered body, and a cutting step of cutting the plate-shaped sintered body to produce a circular or elliptical ceramic substrate in plan view A method for manufacturing a ceramic substrate characterized by the following.

Conventionally, when sintering an unsintered body, the unsintered body is put into a crucible for hot pressing, but a release agent is placed between the unsintered body and a molding die. Distribute. This release agent uses BN or carbon. However, when the unsintered body is a disc, the gap between the crucible wall surface and the unsintered body is varied, and the release agent layer is formed in a thin portion. There has been a problem that the sintered body cannot be taken out of the crucible because the wall surface of the crucible has adhered to the sintered body.

In the present invention, both the crucible wall surface and the side surface of the green body are flat, and the thickness of the release agent layer between the wall surface of the crucible and the side surface of the green body can be easily made uniform. For this reason, the problem that the crucible wall surface and the sintered body adhere to each other at the portion where the release agent layer is thin does not occur. Further, as shown in FIG. 16A, a release agent 74 such as BN is applied to one surface of the guide plate 73 (the surface in contact with the unsintered body), and as shown in FIG. By disposing the guide plate 73 having the layer of the release agent 74 between the wall surface of the crucible 71 and the green body 800,
The thickness of the release agent layer can be controlled, and the sintered body can be easily taken out of the crucible.

As the guide plate 73, ceramic or carbon can be used. When the green body is aluminum nitride, an aluminum nitride substrate to which no sintering aid (such as yttria) is added is desirable. This is because the sintering aid that has exuded during sintering can be absorbed and adhesion between the guide plate and the crucible can be prevented. The polygon in the present invention may be a pentagon or more, and more preferably a hexagon or more and has an even number of diagonals (hexagon, octagon, etc.). This is because the bilateral symmetry is excellent.

A second aspect of the present invention is a method of manufacturing a circular or elliptical ceramic substrate in plan view having a conductor layer provided on the surface or in the inside thereof. A printing step of printing a conductor paste on the sheet, a laminate production step of laminating another green sheet on the green sheet on which the conductor paste is printed to produce a green sheet laminate, and cutting the green sheet laminate Cutting process to produce a polygonal laminate by applying, and firing the polygonal laminate, a sintered body production step of producing a polygonal plate-shaped sintered body,
And a cutting step of cutting the plate-like sintered body to produce a circular or elliptical ceramic substrate in plan view.

In the conventional method of manufacturing a ceramic substrate, a rectangular plate-shaped sintered body is manufactured, and then a circular ceramic substrate is cut out by performing a cutting process. The wear and tear was severe, and the manufacturing cost had increased. However, in the second aspect of the present invention, for example, a rectangular green sheet laminate is cut into a polygon such as a regular hexagon at the stage of producing the green sheet laminate, so that cutting after firing becomes easy.
Further, at the stage of the green sheet laminate, the cutting process is extremely easy, and in some cases, the chips of the green sheet can be used again as a raw material. It can be significantly reduced.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A first method of manufacturing a ceramic substrate according to the present invention is a method of manufacturing a circular or elliptical ceramic substrate having a conductor layer provided on its surface or inside. A step of manufacturing a sintering polygonal body, a step of firing the polygonal body to produce a polygonal plate-like sintered body, and a step of cutting the plate-like sintered body to obtain a plan view. And a cutting process for producing a circular or elliptical ceramic substrate.

In the first aspect of the present invention, the polygonal body produced in the step of producing an unsintered polygonal body is not limited to the green sheet laminate described in the second aspect of the present invention, but includes ceramic powder. Put the granules in a mold, etc.
It may be a formed form formed by pressing.
In this case, the cutting process may not be necessary. In any case, after the above steps, the ceramic substrate is manufactured through the steps described in the second aspect of the present invention described below.

Hereinafter, description will be given along the second embodiment of the present invention, but the present invention is not limited to this. The method for manufacturing a ceramic substrate according to the second aspect of the present invention is a method for manufacturing a circular or elliptical ceramic substrate in a plan view having a conductor layer provided on the surface or inside thereof, after forming a rectangular green sheet. A printing step of printing a conductor paste on the green sheet, a laminate manufacturing step of stacking another green sheet on the green sheet on which the conductor paste is printed to form a green sheet laminate, and a green sheet laminate. A cutting step of producing a polygonal laminate having five or more corners by subjecting the polygonal laminate to firing,
Including a sintered body manufacturing step of manufacturing a polygonal plate-shaped sintered body, and a cutting step of cutting the plate-shaped sintered body to produce a circular or elliptical ceramic substrate in plan view It is characterized by the following.

The ceramic substrate to which the production method of the present invention is applied is a circular or elliptical ceramic substrate having a conductor layer provided on the surface or inside thereof. Its use is not particularly limited. When the conductor layer is an electrostatic electrode, it functions as an electrostatic chuck; when the conductor layer is a resistance heating element, it functions as a hot plate; and when the conductor layer is a guard electrode and / or a ground. If it is an electrode, it functions as a wafer prober.

Here, a method of manufacturing a ceramic substrate functioning as an electrostatic chuck will be described first.
A method for manufacturing a ceramic substrate that functions as a hot plate and a method for manufacturing a ceramic substrate that functions as a wafer prober will be sequentially described.

However, the basic method of manufacturing a ceramic substrate is as follows.
Since there is almost no change, in the case of the method of manufacturing the hot plate and the wafer prober, only the portions different from the method of manufacturing the electrostatic chuck will be described.

FIGS. 1A to 1C and FIGS. 2D to 2 D
(F) is sectional drawing which showed typically some processes in the manufacturing method of the electrostatic chuck which is an example of the manufacturing method of the ceramic substrate of this invention.

(1) In the present invention, first, similarly to the conventional case, a ceramic raw material powder such as a nitride ceramic and a carbide ceramic is mixed with a sintering aid powder, a binder, a solvent and the like to form a slurry. Prepare and use this slurry,
A green sheet is prepared by a doctor blade method or the like.

The green sheet preferably has a small average thickness variation and a relatively low surface roughness. If the surface roughness is large, when a conductive paste layer or the like is formed thereon, the thickness of the conductive paste layer will vary, and the characteristics of the manufactured electrostatic electrodes and resistance heating elements will vary from place to place. This is because it occurs.

The ceramic material constituting the ceramic substrate to be manufactured 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 such as aluminum nitride, silicon nitride, and boron nitride. Examples of the carbide ceramic include metal carbide ceramics such as silicon carbide, zirconium carbide, tantalum carbide, and tungsten carbide.

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

[0030] Among these ceramics, nitride ceramics and carbide ceramics are preferable. Among the above nitride ceramics, aluminum nitride is most preferred. This is because the thermal conductivity of the manufactured ceramic substrate is the highest at 180 W / m · K. Further, among the above carbide ceramics, silicon carbide is preferable. This is because the thermal conductivity is relatively high and the mechanical properties at high temperatures are excellent.

The ceramic raw material powder may be, for example, an aluminum nitride powder having an oxide layer formed on the surface by firing in an oxidizing atmosphere.

If necessary, a sintering aid such as yttria, alumina, carbon, boron, silica, a sulfur compound or a catalyst may be added. The average particle size of the raw material powder is
0.1-5 μm is preferred.

The binder used in preparing the slurry is preferably at least one selected from an acrylic binder, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol. As the solvent, at least one selected from α-terpineol and glycol is desirable.

The viscosity of the green sheet before drying is 1 × 1
0 ⁴ to 4 × 10 ⁴ cP is preferred. By setting the green sheet in such a viscosity range, the variation in the thickness of the green sheet can be reduced and the surface roughness can be reduced.

Thereafter, the green sheet is heated at 50 to 200 ° C.
For 10 to 60 minutes to make the green sheet easy to handle in a subsequent step. The green sheet 50 produced in this manner has a rectangular shape as shown in FIG. This is because a green sheet formed continuously in a sheet shape (strip shape) is cut by a cutter or the like at regular intervals.

After the drying, the green sheet 50 contains
If necessary, a portion serving as a through hole for inserting a lifter pin of a silicon wafer, a portion serving as a concave portion for embedding a thermocouple,
A through hole can be provided in a portion where a through hole is formed or the like. The through holes can be formed by punching or the like.

These through holes and recesses may be provided after forming the green sheet laminate, or may be formed by using a drill or blast treatment after forming the sintered body. The average of the thickness of the green sheet 50 is 0.1 to 5 m
m is preferable.

(2) Next, in a printing step, as in the conventional case, printing is performed on the surface of the green sheet 50 using a conductive paste containing a metal or the like, and the green sheet 50 is used for electrostatic electrodes and / or resistance heating. Form paste layer for body. Also, as shown in FIG. 17A, the through-holes and the like are filled with a conductive paste.

Printing is performed in consideration of the shrinkage ratio of the green sheet 50 so that a resistance heating element or an electrode layer having a desired aspect ratio can be obtained. As the conductive paste, a conductive paste containing conductive ceramic, metal particles, or the like is used.

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

The average particle size of the conductive ceramic particles and metal particles is preferably 0.1 to 5 μm. These particles are
This is because it is difficult to print the conductor paste if it is too large or too small.

As such a conductive 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 kind of binder selected from acrylic, ethyl cellulose, butyl cellosolve and polyvinyl alcohol, α A conductor paste prepared by mixing 1.5 to 10 parts by weight of at least one solvent selected from terpineol, glycol, ethyl alcohol and butanol; In this case, the viscosity of the prepared conductor paste is 5 × 10 ⁴ to 50 × 10 ⁴ c
P (50 to 500 Pa · s) is preferred.

The shape of the electrostatic electrode layer when manufacturing the electrostatic chuck includes, for example, the shapes shown in FIGS. 4, 9 and 10. Examples of the shape of the resistance heating element include a concentric shape as shown in FIG. 5, and a concentric shape and a bent shape (a shape formed of a straight line portion and a bent portion).
And a combination thereof.

After forming the conductive paste layer on the green sheet and filling the through holes and the like with the conductive paste,
The conductor paste layer is dried to obtain a green sheet having the conductor paste layer (FIG. 1A). FIG.
(A) does not show a conductor paste layer.

(3) Next, as a laminate production step, one or a plurality of green sheets 50 on which no conductor paste is printed are placed above and below each green sheet 50 having such a conductor paste layer. The green sheet laminate 500 is prepared by appropriately laminating the laminate and pressing the laminate under heating (FIG. 1B). The heating temperature during the production of the laminate is preferably 50 to 300 ° C., and the pressure for pressurization is 2 to 20 MPa (20 to 200 kg / cm).
² ) is preferred.

The number of stacked green sheets on which the conductor paste layer is not formed may be appropriately increased or decreased according to the thickness of the ceramic substrate, the positions where the electrodes and the resistance heating elements are formed, and the like. The green sheet laminated on the green sheet on which the conductive paste layer for the electrostatic electrode is formed is a sheet of a portion to be a ceramic dielectric film, and may have a different composition from the green sheet to be a lower ceramic layer. Good.

On the lower surface of the green sheet 50 on which the conductive paste filling layer for through holes is formed, usually,
Green sheet 50 on which no conductor paste layer is formed
This is to prevent the end faces of the through holes from being exposed and being oxidized during firing. 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. Further, it may be covered with a gold solder made of an Au-Ni alloy.

(4) Thereafter, as a cutting step, the green sheet laminate is cut to obtain a polygonal laminate 700 having five or more corners (FIG. 1C). Cutting is
Usually, a cutter used for cutting a green sheet or the like may be used. The shape of the polygonal laminate 700 is not particularly limited, and may be a pentagon or a heptagon. However, in consideration of the ease of cutting the green sheet 50, the ease of cutting after manufacturing the sintered body, and the like. Then, a hexagon is preferable. The ceramic substrate to be manufactured may have an elliptical shape in plan view. However, the shape of the ceramic substrate is generally a circular shape in plan view. Therefore, the polygon is preferably a regular polygon (regular hexagon).

(5) Thereafter, as a sintered body manufacturing process, the polygonal laminated body 700 is placed inside a crucible 71 or the like in which a concave portion is formed such that the shape of the polygonal laminated body 700 when viewed from above is the same polygon. (FIG. 2 (d)) and, if necessary, sintering while pressing from above and below, and sintering the ceramic powder in the green sheet and the metal powder in the conductive paste to form a polygonal plate-shaped sintered body 72. It is manufactured (FIG. 2E).

The firing temperature is 1000 to 2000.
° C., the pressure of the pressurization at the time of firing is 10 to 20 MPa (10
0 to 200 kg / cm ² ) is preferred. 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 firing step, through holes, electrostatic electrodes, resistance heating elements, and the like are formed.

After the ceramic substrate is manufactured by the above-described method, annealing may be performed at 1400 to 2000 ° C. Thereby, impurities such as oxygen contained in the crystal particles are discharged out of the crystal, and the thermal conductivity is improved.

(6) Next, as a cutting step, a polygonal plate-shaped sintered body 72 is cut to produce a circular or elliptical ceramic substrate 1 in plan view (FIG. 2).
(F)). As a cutting method, for example, a diamond cutter or the like made of an endless tape-shaped flat blade is used.
There is a method of cutting as shown by a dashed line.

In this case, as compared with a rectangle (square), there are many portions in contact with the circle and the length of the portion to be cut is short, so that cutting can be performed relatively easily. Thereafter, the cut surface is polished using a grindstone or the like, so that the cut surface has an accurate circular shape or the like and the roughness of the side surface is within a predetermined range.

Thereafter, when a resistance heating element is provided on the bottom surface of the ceramic substrate, a conductor paste layer is formed on the bottom surface of the ceramic substrate, and then heated and fired to form a resistance heating element. The method of forming the resistance heating element will be described later in detail.

Thereafter, as in the conventional case, a blind hole or the like for connecting an external terminal is provided, and the external terminal is provided in the blind hole through a brazing material such as gold brazing or solder. Further, a bottomed hole is provided as necessary, and a thermocouple is embedded therein. As the solder, alloys such as silver-lead, lead-tin, and bismuth-tin can be used. The thickness of the solder layer or the brazing material layer is desirably 0.1 to 50 μm.

In the method of manufacturing a ceramic substrate, since the polygonal laminated body 700 is manufactured, as described above, the cutting after the production of the sintered body is facilitated.
Processing can be performed in a short time. In addition, the amount of cutting is reduced and the amount of wear of the cutting tool is also reduced, so that the manufacturing cost can be reduced.

Next, the electrostatic chuck made of the ceramic substrate manufactured by the above method will be described. FIG.
FIG. 4 is a longitudinal sectional view schematically showing an embodiment of the electrostatic chuck manufactured by the above method, FIG. 4 is a sectional view taken along line AA of the electrostatic chuck shown in FIG. 3, and FIG. FIG. 4 is a sectional view taken along line BB of the electrostatic chuck shown in FIG. 3.

In this electrostatic chuck 101, an electrostatic electrode layer composed of a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer 3 is embedded in a disk-shaped ceramic substrate 1. A thin ceramic layer 4 (hereinafter, referred to as a ceramic dielectric film) is formed on the electrode layer. A silicon wafer 9 is placed on the electrostatic chuck 101 and is grounded.

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

In order to control the temperature of the silicon wafer 9, a resistance heating element 5 having a concentric circular shape in plan view as shown in FIG. 4 is provided inside the ceramic substrate 1. at both ends of the external terminals 6 connected, is fixed, so that the voltages V ₁ is applied. Although not shown in FIG. 3, the ceramic substrate 1 has a bottomed hole 11 for inserting a temperature measuring element and a lifter pin (FIG. 5) for supporting and raising and lowering the silicon wafer 9 as shown in FIG. (Not shown) are formed. Note that the resistance heating element 5 may be formed on the bottom surface of the ceramic substrate 1.

When the electrostatic chuck 101 functions, a DC voltage V ₂ is applied to the chuck positive electrostatic layer 2 and the chuck negative electrostatic layer 3. As a result, the silicon wafer 9 is adsorbed and fixed to the chuck positive electrode electrostatic layer 2 and the chuck negative electrode electrostatic layer 3 via the ceramic dielectric film 4 by the electrostatic action (Coulomb force) of these electrodes. Will be done. After fixing the silicon wafer 9 on the electrostatic chuck 101 in this manner, the silicon wafer 9
Can be subjected to various processes such as CVD.

Next, the ceramic substrate constituting the electrostatic chuck will be described. The ceramic substrate refers to a portion other than the ceramic dielectric film in this electrostatic chuck. The electrostatic chuck may or may not include the resistance heating element.
If this electrostatic chuck has a resistance heating element,
It is preferably used at 100 ° C. or higher, most preferably at 200 ° C. or higher.

The ceramic substrate preferably has a maximum pore size of 50 μm or less, and a porosity of 5% or less. Further, the ceramic substrate has no pores or, if pores exist, the maximum pore diameter is desirably 50 μm or less.

When no pores are present, the withstand voltage at a high temperature is particularly high, and when some pores are present, the fracture toughness becomes higher. Or either the design for this is the vary required characteristics. It is not clear why the presence of the pores increases the fracture toughness value, but it is presumed that the cracks are stopped by the pores.

In the present invention, the pore diameter of the maximum pore is desirably 50 μm or less because if the pore diameter exceeds 50 μm, it becomes difficult to secure a withstand voltage characteristic at a high temperature, especially at 200 ° C. or more. is there. The maximum pore size is 10
μm or less is desirable. This is because the amount of warpage at 200 ° C. or higher is reduced.

The porosity and the maximum pore diameter can be adjusted by the pressurization time, pressure, temperature, and additives such as SiC and BN during sintering. As described above, since SiC and BN inhibit sintering, pores can be introduced.

When measuring the pore diameter of the maximum pore, five samples were prepared, and the surfaces thereof were mirror-polished,
The surface is photographed at 10 times 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 .

The diameter of the ceramic substrate is desirably 200 mm or more. In particular, it is desirable to be 12 inches (300 mm) or more. In the case of a large substrate having a diameter of more than 150 mm, the cutting time after manufacturing the sintered body becomes longer. Therefore, as in the present invention, the polygonal laminated body should be formed at the stage of producing the green sheet laminated body. This makes it possible to shorten the processing time and the like.

The thickness of the ceramic substrate is desirably 50 mm or less, particularly desirably 25 mm or less. When the thickness of the ceramic substrate exceeds 25 mm, the heat capacity of the ceramic substrate may be too large. In particular, when the temperature control means is provided for heating and cooling, the temperature followability is reduced due to the large heat capacity. This is because it may happen. The thickness of the ceramic substrate is optimally more than 1.5 mm and 5 mm or less. When the thickness of the ceramic substrate is 1.5 mm or less, a large ceramic substrate having a diameter of more than 150 mm has a large amount of warpage and is not practical.

The ceramic substrate desirably contains 0.05 to 20% by weight of oxygen. This is because the segregation of oxygen at the grain boundaries can improve the fracture toughness value. If the oxygen content is less than 0.05% by weight, sintering does not proceed and the porosity increases, and the thermal conductivity decreases. Conversely, if the oxygen amount exceeds 20% by weight, the amount of oxygen in the grain boundaries increases. Is too large, the thermal conductivity is reduced, and the temperature raising / lowering characteristics are lowered.

In order to make the ceramic substrate contain oxygen, as described above, the raw material powder is fired in an oxidizing atmosphere, or the raw material powder is mixed with a metal oxide and fired. 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), and calcium carbonate (CaCO ₃ ). Can be The content of these metal oxides is preferably 0.1 to 20% by weight.

According to the present invention, 5 to 50
Desirably, it contains 00 ppm of carbon.
By containing carbon, the ceramic substrate can be blackened, and radiant heat can be sufficiently used when used as a heater. The carbon may be amorphous or crystalline. When amorphous carbon is used, a decrease in volume resistivity at high temperatures can be prevented, and when crystalline carbon is used, a decrease in thermal conductivity at high temperatures can be prevented. Because. Therefore, depending on the application, both crystalline carbon and amorphous carbon may be used in combination. The content of carbon is 50 to 2
000 ppm is more preferred.

When carbon is contained in the ceramic substrate, it is desirable that the carbon be contained so that the lightness is N4 or less as a value based on JIS Z 8721. What has this level of brightness is the amount of radiant heat,
This is because the concealing property is excellent.

Here, the lightness N is defined as 0 for an ideal black lightness, 10 for an ideal white lightness, and the brightness of the color between these black lightness and white lightness. Each color is divided into ten so that the perception of the color is equal, and displayed by symbols N0 to N10. The actual measurement of lightness is N0 to N1
The comparison is made with the color chart corresponding to 0. Decimal point 1 in this case
The place is 0 or 5.

The material of the ceramic dielectric film constituting the electrostatic chuck is not particularly limited, and may be a nitride ceramic,
Examples thereof include carbide ceramics and oxide ceramics, and among these, nitride ceramics and carbide ceramics are preferable. As the above-mentioned nitride ceramic, the same as the above-mentioned ceramic substrate can be mentioned, but it is preferable that the nitride ceramic contains oxygen.

For example, in order to make the above-mentioned nitride ceramic contain oxygen, the raw material powder of the nitride ceramic is fired in an oxidizing atmosphere, or the raw material powder is mixed with a metal oxide and fired. Examples of the metal oxide include alumina (Al ₂ O ₃ ) and silicon oxide (SiO ₂ ). The addition amount of these metal oxides is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the nitride ceramic.

The thickness of the ceramic dielectric film is set to 50 to 50
By setting the thickness to 00 μm, a sufficient withstand voltage can be secured without lowering the chucking force. 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 thickness of the ceramic dielectric film is 50
If it exceeds 00 μm, the distance between the silicon wafer and the electrostatic electrode will be long, and the ability to adsorb the silicon wafer will be reduced. The thickness of the ceramic dielectric film is 100
〜1500 μm is preferred.

In the electrostatic chuck 101, the ceramic dielectric film 4 is made of a nitride ceramic containing oxygen, has a porosity of 5% or less, and has a maximum pore diameter of 5%.
It is desirable that the thickness be 0 μm or less. It is desirable that the pores in the ceramic dielectric film 4 be constituted by pores independent of each other. In the ceramic dielectric film 4 having such a configuration, a gas or the like that lowers the withstand voltage permeates the ceramic dielectric film to corrode the electrostatic electrodes,
Even at high temperatures, the withstand voltage of the ceramic dielectric film does not decrease.

When the porosity exceeds 5%, the number of pores increases, and the pore diameter becomes too large. As a result, the pores easily communicate with each other. With a ceramic dielectric film having such a structure, the withstand voltage is reduced. Further, when the pore diameter of the maximum pore exceeds 50 μm, it becomes difficult to secure a withstand voltage at high temperatures even if an oxide exists at the grain boundary. The porosity is preferably 0.01% to 3%, and the maximum pore diameter is preferably 0.1 μm to 10 μm.

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

In the present invention, the reason why a certain amount of pores may exist in the ceramic dielectric film is that the fracture toughness value can be further increased, thereby further improving the thermal shock resistance. Can be improved.

FIGS. 9 and 10 are horizontal cross-sectional views schematically showing electrostatic electrodes of another electrostatic chuck. In the electrostatic chuck 20 shown in FIG. In the electrostatic chuck shown in FIG. 10, chuck positive electrode electrostatic layers 32a and 32b each having a shape obtained by dividing a circle into four parts are formed in the electrostatic chuck shown in FIG. And chuck negative electrode electrostatic layers 33a and 33b are formed. Further, the two positive electrode electrostatic layers 22a and 22b and the two chuck negative electrode electrostatic layers 33a and 33b are formed to cross each other. In the case of forming an electrode in which a circular electrode or the like is divided, the number of divisions is not particularly limited, and may be five or more, and the shape is not limited to a sector.

As the electrostatic chuck to be manufactured in the present invention, for example, as shown in FIG. 3, a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer are provided between a ceramic substrate 1 and a ceramic dielectric film 4. The electrostatic chuck 101 has a structure in which a layer 3 is provided and a resistance heating element 5 is provided inside the ceramic substrate 1. As shown in FIG. 6, a chuck positive electrode is provided between the ceramic substrate 1 and the ceramic dielectric film 4. An electrostatic layer 2 and a chuck negative electrode electrostatic layer 3 are provided.
An electrostatic chuck 201 having a configuration in which a resistance heating element 25 is provided on the bottom surface of a chuck, a chuck positive electrostatic layer 2 and a chuck negative electrostatic layer between a ceramic substrate 1 and a ceramic dielectric film 4 as shown in FIG. And an electrostatic chuck 301 in which a metal wire 7 serving as a resistance heating element is embedded in the ceramic substrate 1 as shown in FIG.
Positive electrode electrostatic layer 2 between chuck and ceramic dielectric film 4
And a chuck negative electrode electrostatic layer 3, and an electrostatic chuck 401 having a configuration in which a Peltier element 8 including a thermoelectric element 81 and a ceramic plate 82 is formed on the bottom surface of the ceramic substrate 1.

When a Peltier element is used as the temperature control means as in the electrostatic chuck shown in FIG. 8, it is advantageous because both heat generation and cooling can be performed by changing the direction of current flow. The Peltier element 8 is a p-type,
It is formed by connecting n-type thermoelectric elements 81 in series and joining them to a ceramic plate 82 or the like. As the Peltier element, for example, silicon-germanium-based,
Bismuth / antimony-based materials, lead / tellurium-based materials, and the like can be given.

As shown in FIGS. 3 to 7, in the electrostatic chuck, 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 elements 5 and the metal wires 7 are formed inside the ceramic substrate 1, connection portions (through holes) 16 and 17 for connecting these to external terminals are required.

The through holes 16 and 17 are formed by filling a refractory metal such as tungsten paste and molybdenum paste and a conductive ceramic such as tungsten carbide and molybdenum carbide.

The connection 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 terminals 6 and 18 are connected using the through holes as connection pads.

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

The ratio of Au / Ni is [81.5-82.
5 (% by weight)] / [18.5 to 17.5 (% by weight)] is desirable. The thickness of the Au—Ni layer is desirably 0.1 to 50 μm. This is because the range is sufficient to secure the connection.
Moreover, 500-1000 at a high vacuum of 10 ^-6 to 10 ^-5 Pa.
When used at high temperature of ℃, Au-Cu alloy deteriorates,
An Au-Ni alloy is advantageous without such deterioration.
The total amount of impurity elements in the Au—Ni alloy is 100%.
It is desirable that the amount be less than 1 part by weight when it is used as a part by weight.

In the present invention, a thermocouple can be embedded in the bottomed hole of the ceramic substrate as required. 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 thermocouple metal wire is
The diameter 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 joint portion is small, and the temperature is accurate,
In addition, it is 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, JIS
-C-1602 (1980).
Type, R type, B type, S type, E type, J type, T type thermocouple.

When the electrostatic chuck 101 (see FIGS. 3 and 4) is manufactured, as described above, a conductive paste layer for an electrostatic electrode or a resistance heating element is formed and laminated on a green sheet. When manufacturing the electrostatic chuck 201 (see FIG. 6), a ceramic substrate having an electrostatic electrode layer is manufactured, and then a conductive paste is printed and fired on the bottom surface of the ceramic substrate to form the resistance heating element 25. Thereafter, the metal coating layer 25a may be formed by electroless plating or the like.
When the electrostatic chuck 301 (see FIG. 7) is manufactured, a metal wire is placed on a green sheet instead of forming a conductive paste layer serving as a resistance heating element. The electrostatic chuck may be manufactured in substantially the same manner as in the above case. Further, the electrostatic chuck 401
In the case of manufacturing (see FIG. 8), 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.

FIG. 11 is a cross-sectional view schematically showing a support container 41 for fitting the electrostatic chuck of the present invention having the above configuration. The support container 41 includes the electrostatic chuck 1
01 is fitted through the heat insulating material 45. In addition, the support container 11 has a refrigerant outlet 42.
Is formed, and the refrigerant is blown from the refrigerant injection port 44 and goes out of the suction port 43 through the refrigerant discharge port 42, and the electrostatic chuck 101 is cooled by the action of the refrigerant. You can do it. The support container 41 shown in FIG. 11 is of a type in which a ceramic substrate is fitted into the support container 41, but the support container is of a type in which the ceramic substrate is placed thereon and then fixed. Is also good.

Next, a method of manufacturing a ceramic substrate functioning as a hot plate (ceramic heater) will be described. In this method of manufacturing a hot plate, a ceramic heater having a resistance heating element inside is substantially the same as the above-described method of manufacturing the electrostatic chuck, except that only the conductor paste for the resistance heating element is printed on the surface of the green sheet. To manufacture. Therefore, only the method of forming the resistance heating element will be described here.

The resistance heating element is preferably made of a metal such as a noble metal (gold, silver, platinum, palladium), tungsten, molybdenum, nickel, or a conductive ceramic such as a carbide of tungsten or molybdenum.
This is because the resistance value can be increased, the thickness itself can be increased for the purpose of preventing disconnection, and the like, and it is hard to be oxidized and the thermal conductivity does not easily decrease. These may be used alone or in combination of two or more.

Since the resistance heating element needs to make the temperature of the entire ceramic substrate uniform, a concentric pattern as shown in FIG. 5 or a combination of a concentric pattern and a bent line pattern is used. Are preferred.
Also, the thickness of the resistance heating element in the obtained ceramic heater is 1 to 50 μm, and the width thereof is 5 to 20 mm.
It is desirable to set the width and thickness of the conductor paste.

The resistance value can be changed by changing the thickness or width of the resistance heating element, but the above range is most practical. The resistance value of the resistance heating element is
The thinner and thinner, the larger.

When the resistance heating element is provided inside, the distance between the heating surface and the resistance heating element becomes short, and the uniformity of the surface temperature is reduced. Therefore, it is necessary to increase the width of the resistance heating element itself. Further, since the resistance heating element is provided inside the ceramic substrate, it is not necessary to consider the adhesion to the ceramic substrate.

The resistance heating element may have a cross section of any of a square, an ellipse, a spindle, and a kamaboko, but is preferably flat. This is because the flat surface is more likely to radiate heat toward the heating surface, so that the amount of heat propagation to the heating surface can be increased, and the temperature distribution on the heating surface is less likely to occur. The resistance heating element may have a spiral shape.

When forming the resistance heating element inside the ceramic substrate, it is desirable to form the resistance heating element in an area up to 60% in the thickness direction from the bottom surface. This is because the temperature distribution on the heating surface can be eliminated and the semiconductor wafer can be uniformly heated.

In the present invention, since a ceramic substrate is manufactured using green sheets, when a hot plate having only a resistance heating element is manufactured, the resistance heating element is formed inside the ceramic substrate. In the method of manufacturing the electric chuck, the electrostatic electrode may be formed inside the ceramic substrate, and the resistance heating element may be formed on the bottom surface of the ceramic substrate. Therefore, here, the case where the resistance heating element is formed on the bottom surface of the ceramic substrate will also be described.

In the case where a resistance heating element is formed on the bottom surface of the ceramic substrate, usually, after firing, the ceramic substrate is manufactured, and then the above-mentioned conductive paste layer is formed on the surface of the ceramic substrate.
By firing, a resistance heating element is formed.

[0103] The conductive paste used for forming the conductive paste on the bottom surface of the fired ceramic substrate or for forming the conductive paste layer on the surface of the green sheet is not particularly limited. Particles or conductive ceramic particles are preferable, and those containing a resin, a solvent, a thickener, and the like are preferable.

Examples of the material of the metal particles and the conductive ceramic particles include those described above. The particle size of these metal particles or conductive ceramic particles is 0.1 to 10
0 μm is preferred. If it is too fine, less than 0.1 μm, it is liable to be oxidized, while if it exceeds 100 μm, sintering becomes difficult and the resistance value becomes large.

The shape of the metal particles may be spherical,
It may be scaly. When these metal particles are used, they may be a mixture of the above-mentioned spheres and the above-mentioned flakes.

When the metal particles are flakes or a mixture of spheres and flakes, the metal oxide between the metal particles is easily held, and the adhesion between the resistance heating element and the ceramic substrate is improved. This is advantageous because it can ensure the performance and can increase the resistance value.

As the resin used for the conductor paste, for example, acrylic resin, epoxy resin, phenol resin and the like can be mentioned. Examples of the solvent include isopropyl alcohol. Examples of the thickener include cellulose and the like. When the resistance heating element is provided inside the ceramic substrate, the viscosity of the conductive paste is 5 × 10 ⁴ to 50 × 10 ⁴ cP (50 to 500 Pa).
-S) is preferred.

When forming a conductor paste for a resistance heating element on the surface of a ceramic substrate, a metal oxide is added to the conductor paste in addition to the metal particles, and the metal particles and the metal oxide are sintered. It is preferable that they are tied. As described above, by sintering the metal oxide together with the metal particles, the ceramic substrate and the metal particles can be more closely adhered.

Although the reason for improving the adhesion to the ceramic substrate by mixing the above metal oxide is not clear, the surface of the metal substrate or the surface of the ceramic substrate made of non-oxide has a slight surface. It is considered that the oxide film is oxidized to form an oxide film, and the oxide films are sintered and integrated via the metal oxide, so that the metal particles and the ceramic adhere to each other. Further, when the ceramic constituting the ceramic substrate is an oxide, the surface is naturally made of an oxide, so that a conductor layer having excellent adhesion is formed.

Examples of the metal oxide include, for example, oxide
Lead, zinc oxide, silica, boron oxide (B _Two O_Three ), Al
Selected from the group consisting of Mina, Yttria and Titania
At least one is preferred. These oxides have resistance
Metal particles and ceramics can be used without increasing the resistance of the heating element.
This is because the adhesion to the substrate can be improved.
You.

The ratio of the above-mentioned lead oxide, zinc oxide, silica, boron oxide (B ₂ O ₃ ), alumina, yttria, and titania is as follows: 1-10, silica 1-30, boron oxide 5-50, zinc oxide 20-70, alumina 1
-10, yttria 1-50, titania 1-50, and the total is preferably adjusted so as not to exceed 100 parts by weight. By adjusting the amounts of these oxides in these ranges, the adhesion to the ceramic substrate can be particularly improved.

The addition amount of the metal oxide to the metal particles is preferably 0.1% by weight or more and less than 10% by weight. The area resistivity when the resistance heating element is formed using the conductor paste having such a configuration is preferably 1 to 45 mΩ / □.

When the area resistivity exceeds 45 mΩ / □, the heat generation becomes too large with respect to the applied voltage, and it is difficult to control the heat generation in a ceramic substrate for a semiconductor device provided with a resistance heating element on the surface. Because. When the addition amount of the metal oxide is 10% by weight or more, the sheet resistivity is 50%.
It exceeds mΩ / □, and the calorific value becomes too large to make temperature control difficult, and the uniformity of the temperature distribution decreases.

When the resistance heating element is formed on the surface of the ceramic substrate, it is preferable that a metal coating layer is formed on the surface of the resistance heating element. This is to prevent the internal metal sintered body from being oxidized to change the resistance value.
The thickness of the metal coating layer to be formed is preferably 0.1 to 10 μm.

The metal used for forming the metal coating layer is not particularly limited as long as it is a non-oxidizing metal.
Specifically, for example, gold, silver, palladium, platinum, nickel and the like can be mentioned. These may be used alone,
Two or more kinds may be used in combination. Of these, nickel is preferred. 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.

Also in the method of manufacturing the ceramic substrate constituting the hot plate, by forming the polygonal laminated body 700 of the green sheets, the cutting after the production of the sintered body becomes easy, and the processing is performed in a short time. As a result, the manufacturing cost of the hot plate can be reduced.

The resistance heating element constituting the hot plate manufactured by the above method has a concentric shape like the resistance heating element formed on the electrostatic chuck of FIG. 5, for example. FIG. 12 is a partially enlarged sectional view showing a part of the ceramic heater.

Although not shown, the ceramic substrate 61
It is formed in a disk shape, and inside the ceramic substrate 61, resistance heating elements 62 are formed in a concentric pattern or the like, and these resistance heating elements 62 are a pair of double concentric circles close to each other. The external terminal 63 serving as an input / output terminal is connected to both ends of the circuit through a through hole 69 as a single circuit.

The ceramic substrate 61 has through holes 65.
The lifter pins 66 are inserted through the through holes 65, and the silicon wafer 9 is held. By moving the lifter pins 66 up and down, the silicon wafer 9 is received from the carrier, the silicon wafer 9 is placed on the heating surface 61a of the ceramic substrate 61 and heated, or the silicon wafer 9 is heated on the heating surface 61a. From 50 to 50
It can be supported and heated in a state of being separated by 00 μm.

Further, a through hole or a concave portion is provided in the ceramic substrate 61, and a pin having a spire or a hemispherical tip is inserted into the through hole or the concave portion, and then the support pin is slightly projected from the ceramic substrate. By supporting the silicon wafer with the support pins, the silicon wafer can be supported and heated in a state of being separated from the heating surface by about 50 to 2000 μm.

A bottomed hole 64 for inserting a temperature measuring element such as a thermocouple is provided in the bottom surface 61a of the ceramic substrate 61. Then, when the resistance heating element 62 is energized, the ceramic substrate 61 is heated, so that an object to be heated such as a silicon wafer can be heated.

In the case where a resistance heating element is provided inside the ceramic substrate 61, a blower for a refrigerant such as air may be provided as a cooling means in a support container for fixing the ceramic substrate. 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.

Next, a method of manufacturing a ceramic substrate functioning as a wafer prober will be described. In this wafer prober manufacturing method, first, a conductor paste for a guard electrode or a ground electrode is printed on the surface of the green sheet,
These green sheets are laminated. Between the green sheet on which the conductor paste for the guard electrode is formed and the green sheet on which the conductor paste for the ground electrode is formed,
A green sheet laminate 500 is formed by sandwiching a plurality of green sheets on which the conductive paste is not printed.
(B)).

For the printing of the guard electrode and the ground electrode, a conductive paste having the same composition as that of the conductive paste used for printing the electrostatic electrode can be used. To print guard electrodes and ground electrodes. As guard electrode and ground electrode,
For example, a rectangular conductor layer non-forming portion 95 as shown in FIG.
a having a lattice shape. The conditions and methods other than those described above in the printing step and the laminate manufacturing step are the same as those in the method for manufacturing the electrostatic chuck shown in FIGS.

Thereafter, a cutting step, a sintered body manufacturing step, and a cutting step are performed in substantially the same manner as the above-described electrostatic chuck manufacturing method, and a disk-shaped ceramic substrate having a guard electrode and a ground electrode therein is provided. To manufacture.

Thereafter, as in the conventional case, a circular groove is formed on the upper surface of the ceramic substrate, a chuck top conductor layer is formed by sputtering or plating, and a suction hole is formed. And the like, to terminate the production of the wafer prober.

In the method of manufacturing the ceramic substrate constituting the wafer prober, the green sheet polygonal laminate 700 (see FIG. 1C) is also produced.
Cutting after the production of the sintered body is facilitated, and the processing can be performed in a short time. As a result, the production cost of the hot plate can be reduced.

FIG. 13 is a cross-sectional view schematically showing one embodiment of a ceramic substrate constituting a wafer prober manufactured by the above method, and FIG. 14 is a plan view of the wafer prober shown in FIG. FIG. 15 is a sectional view taken along line AA of the wafer prober shown in FIG.

In this wafer prober 90, a groove 97 having a concentric circular shape in a plan view is formed on the surface of a disk-shaped ceramic substrate 91.
Are formed, and a plurality of suction holes 98 for sucking the silicon wafer are provided in a part of the groove 97.
Chuck top conductor layer 92 for connecting to a silicon wafer electrode on most of ceramic substrate 91 including groove 97
Are formed in a circular shape.

On the other hand, a concentric heating element 93 as shown in FIG. 5 is provided on the bottom surface of the ceramic substrate 91 to control the temperature of the silicon wafer. External terminals (not shown) are connected and fixed. Further, inside the ceramic substrate 91, a guard electrode 95 and a ground electrode 96 (see FIG. 15) having a lattice shape in plan view are provided for removing stray capacitors and noise. The materials of the guard electrode 95 and the ground electrode 96 may be the same as those of the electrostatic electrode.

The thickness of the chuck top conductor layer 92 is 1 to
20 μm is desirable. If the thickness is less than 1 μm, the resistance value becomes too high to function as an electrode, while if it exceeds 20 μm, the conductor tends to be peeled off due to the stress of the conductor.

As the chuck top conductor layer 92, for example, copper, titanium, chromium, nickel, a noble metal (gold, silver,
At least one metal selected from refractory metals such as platinum, molybdenum, and the like can be used.

In a wafer prober having such a configuration, after a silicon wafer having an integrated circuit formed thereon is mounted thereon, a probe card having tester pins is pressed against the silicon wafer, and a voltage is applied while heating and cooling. To conduct a continuity test.

[0134]

The present invention will be described in more detail with reference to the following examples. (Example 1) Production of electrostatic chuck (see FIGS. 1 and 3) (1) 1000 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size: 0.6 μm), yttria (average particle size:
0.4 [mu] m) 40 parts by weight, 115 parts by weight of an acrylic binder, 5 parts by weight of a dispersant, and 530 parts by weight of an alcohol composed of 1-butanol and ethanol have a viscosity of 1
0 ⁴ using cP paste, after molding by the doctor blade method, by drying, thickness 0.4
A 7 mm rectangular green sheet 50 was obtained (FIG. 1).
(A)).

(2) Next, some of the green sheets were punched to have a diameter of 1.8 mm and 3.0 m.
A portion serving as a through hole for inserting a 5.0 mm lifter pin 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, 3.0 parts by weight of an acrylic resin binder, 3.5 parts by weight of an α-terpineol solvent, and 0.3 part by weight of a dispersant are mixed. A conductor paste A was prepared. 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 resin binder, 3.7 parts by weight of an α-terpineol solvent, and 0.2 parts by weight of a dispersant.

This conductive paste A was printed on a green sheet by screen printing to form a conductive paste layer for a resistance heating element. The printing pattern was a concentric pattern having a width of 10 mm and a thickness of 12 μm.
Further, a conductor paste layer composed of an electrostatic electrode pattern having the shape shown in FIG. 4 was formed on another green sheet. The thickness of this conductor paste layer was 10 μm. Further, a conductive paste B was filled in a through hole for a through hole for connecting an external terminal.

(4) On the green sheet 50 after the above treatment, 34 green sheets 50 on which no conductor paste is printed are laminated on the upper side (heating surface) and 13 green sheets 50 on the lower side, and the electrostatic electrodes are further laminated thereon. A green sheet 50 on which a conductor paste layer made of a pattern is printed is laminated, and two green sheets 50 on which a tungsten paste is not printed are further laminated thereon. These are laminated at 130 ° C. and 8 MPa (8 MPa).
0 kg / cm ² ), the length is 270 mm,
A green sheet laminate 700 having a width of 270 mm was formed (FIG. 1B).

(5) Next, this green sheet laminate 5
00 was placed on a rotatable base provided with a cutter, and cut while rotating the green sheet laminate 500, thereby producing a regular hexagonal polygon laminate 700 (FIG. 1C). reference). The width L of this green sheet
Was 265 mm. The width L is the same as the diameter when an inscribed circle is drawn on this regular hexagon.

(6) Next, the obtained polygonal laminate 700
Is used as a release agent 74 made of BN powder as shown in FIG.
Into a crucible 71 together with a guide plate 73 made of AlN not containing yttria (Y ₂ O ₃ ) coated with (FIG. 2D)
After degreasing for 5 hours at 600 ° C. in nitrogen gas.
3 at 890 ° C, 15MPa (150kg / cm ² )
Hot pressing was performed for a time to obtain a 3 mm-thick regular hexagonal aluminum nitride plate-like sintered body 72 (FIG. 2E).
reference). The width L 'is also the same as the diameter when an inscribed circle is drawn on this regular hexagon. When the sintered body was taken out of the crucible, the crucible and the sintered body did not adhere to each other. (7) Next, this plate-shaped sintered body 72 is cut out into a disk shape of 230 mm using a diamond cutter, and a resistance heating element 5 having a thickness of 6 μm and a width of 10 mm and a thickness of 10 μm are internally formed.
A plate-shaped body made of aluminum nitride having a chuck positive electrode electrostatic layer 2 and a chuck negative electrode electrostatic layer 3 of FIG.
(F)).

(8) Next, the plate obtained in (7) 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.

(9) Further, the portion where the through-hole is formed is cut out to form a blind hole, and Ni-A
An external terminal made of Kovar was connected by heating and reflowing at 700 ° C. using a gold solder made of u. The connection of the external terminals is desirably 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 FIGS. 1 and 3) A regular octagonal green sheet laminate 7 having a width L of 300 mm
An electrostatic chuck was manufactured in the same manner as in Example 1 except that 00 was formed.

Comparative Example 1 Green Sheet Laminate 500
Of the green sheet laminate 500, and thus the green sheet laminate 500 is directly degreased and baked, as in the conventional case, without producing the polygonal laminate 700 of green sheets. An electrostatic chuck was manufactured.

In Example 1 and Comparative Example 1, the time required to cut a disc-shaped ceramic plate from the sintered body produced by firing was measured.
Compared to 1-2 minutes, Comparative Example 1 takes 5 minutes, and Comparative Example 1 takes longer, and by manufacturing the polygonal plate-shaped sintered body 72, it takes less time. A disk-shaped ceramic plate could be cut out.

The diamond cutter was also manufactured in Comparative Example 1.
In the case of (1), when 100 pieces of the sintered body manufactured by the same method were cut, it was necessary to replace it with a new blade. On the other hand, in the case of Example 1, 1000 pieces could be cut. In the case of, it was found that the consumption of the cutter was small.

Example 3 Production of Hot Plate (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size: 0.6 μm), yttrium oxide (Y
₂ O ₃ : yttria, average particle size: 0.4 μm) 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 2 A green sheet 50 having a thickness of 0.47 mm was prepared by using a paste of × 10 ⁴ cP by a doctor blade method.

(2) Next, this green sheet 50
After drying at 0 ° C. for 5 hours, a portion serving as a through hole and a portion serving as a through hole for inserting a lifter pin for supporting a silicon wafer were formed by punching.

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

Tungsten particles 10 having an average particle diameter of 3 μm
A conductive paste B was prepared by mixing 0 parts by weight, 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.

After filling the through holes for the through holes with the conductive paste B, the conductive paste A was printed on a green sheet by screen printing to form a conductive paste layer for the resistance heating element 62. The printing pattern was a concentric pattern, the width of the conductive paste layer was 10 mm, and the thickness thereof was 12 μm.

(4) On the green sheet after the above processing, 37 sheets of green sheet on which no tungsten paste is printed are provided on the upper side (heating surface), 13 sheets on the lower side, 130 ° C.
The layers are laminated at a pressure of 8 MPa (80 kg / cm ² ),
Green sheet laminate 50 having a width of 70 mm and a width of 270 mm
0 (see FIG. 1 (b)).

(5) Next, the obtained green sheet laminate 500 is placed on a rotatable table provided with a cutter, and cut while rotating the green sheet laminate 500 to form a regular hexagon. A polygonal laminate 700 having a shape was produced (see FIG. 1C). The width L of this green sheet was 265 mm. (6) Next, the obtained polygonal laminate 700 is put into a crucible 71 (see FIG. 2D), degreased in a nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 15 MPa (150 kg /
cm ² ) for 10 hours to obtain a regular hexagonal plate-shaped sintered body 72 made of aluminum nitride and having a thickness of 3 mm (see FIG. 2E).

(7) Next, the plate-shaped sintered body 72 was cut out into a disk shape of 230 mm by using a diamond cutter, and a 6 μm thick and 10 mm wide (aspect ratio: 1666) resistance heating was formed inside. A plate-like body having a body 62 (see FIG. 2 (f)). At this time, since the shape of the plate-like sintered body was a regular hexagon, a circular plate-like body could be easily cut out.

(8) Next, the plate obtained in (7) is
After polishing with a diamond grindstone, a mask is placed and Si
A bottomed hole for a thermocouple was formed on the surface by blasting with C or the like.

(9) Further, the plate-shaped body is drilled to form a blind hole, and the external terminal 63 having a T-shaped cross section is formed in the blind hole.
Is inserted and then heated and reflowed at 970 ° C. by using a gold brazing filler made of a Ni—Au alloy (Au: 81.5% by weight, Ni: 18.4% by weight, impurities: 0.1% by weight). The external terminal 63 was brazed and connected to the end of the resistance heating element 62.

(10) A plurality of thermocouples for temperature control are embedded in the bottomed holes, filled with a polyimide resin, and heated at 190 ° C.
For 2 hours to produce a hot plate.

(Embodiment 4) Wafer prober 90 (FIG. 13)
(1) 1000 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), 40 parts by weight of yttria (average particle size 0.4 μm), 115 parts by weight of an acrylic resin binder, 1- A mixed composition obtained by mixing 530 parts by weight of an alcohol composed of butanol and ethanol was molded by a doctor blade method to a thickness of 0.47.
mm green sheet was obtained.

(2) Next, the green sheet was heated to 80 ° C.
After drying for 5 hours, through holes were formed in some of the green sheets by punching to connect the resistance heating elements to external terminals.

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

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

(4) Further, 50 green sheets on which the conductor paste was printed and 50 green sheets on which no conductor paste had been printed were laminated, and 130 ° C., 8 MPa (80 kg / c
m ² ), the length is 360 m
A green sheet laminate 500 having a width of 360 mm and a width of 360 mm was produced (see FIG. 1B).

(5) Next, the obtained green sheet laminate 500 is placed on a rotatable table provided with a cutter, and cut while rotating the green sheet laminate 500 to form a regular hexagon. A polygonal laminate 700 having a shape was produced (see FIG. 1C). The width L of this green sheet was 350 mm.

(6) Next, the obtained polygonal laminate 700
Into a crucible 71 (see FIG. 2 (d)), degrease this laminate in nitrogen gas at 600 ° C. for 5 hours, and hot-press at 1890 ° C. and a pressure of 15 MPa (150 kg / cm ² ) for 3 hours to obtain a width L 'Was a regular hexagonal plate-shaped sintered body 72 made of aluminum nitride having a thickness of 346 mm and a thickness of 3 mm. At this time, since the shape of the plate-like sintered body was a regular hexagon, a circular plate-like body could be easily cut out.

(7) Next, the plate-shaped sintered body 72 was cut into a circular shape having a diameter of 300 mm using a diamond cutter to obtain a ceramic plate-shaped body. Through hole 1
The size of No. 6 was 0.2 mm in diameter and 0.2 mm in depth.

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

(8) After polishing the plate-like body obtained in the above (6) with a diamond grindstone, a mask is placed, and a blast process using SiC or the like is performed on the surface to form a concave portion for a thermocouple and a wafer-absorbing portion. Groove 47 (width 0.5 mm, depth 0.5 mm)
Was provided.

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

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

(11) On the surface where the groove 47 was formed, a titanium layer, a molybdenum layer, and a nickel layer were sequentially formed by a sputtering method. The equipment for sputtering is
SV-4540 manufactured by Japan Vacuum Engineering Co., Ltd. was used.
The sputtering conditions are as follows: atmospheric pressure 0.6 Pa, temperature 100
° C, power 200W, sputtering time 30
Adjusted by each metal within seconds to 1 minute. The thickness of the obtained film was determined from the image of the X-ray fluorescence spectrometer as 0.3 μm for the titanium layer, 2 μm for the molybdenum layer, and 1 μm for the nickel layer.
μm.

(12) The ceramic plate obtained in (8) above was placed 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. Was deposited on the surface of the metal layer formed by sputtering to deposit a nickel layer having a thickness of 7 μm and a boron content of 1% by weight or less, and annealing at 120 ° C. for 3 hours. The surface of the heating element does not pass current and is not covered with electrolytic nickel plating.

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

(13) The air suction hole 48 that passes through the groove 67 to the back surface was formed by drilling, and a blind hole (not shown) for exposing the through hole 660 was provided.
A Ni-Au alloy (81.5% by weight of Au, Ni
An external terminal made of Kovar was connected by heating and reflowing at 970 ° C. using a brazing filler metal consisting of 18.4% by weight and 0.1% by weight of impurities. External terminal pins made of Kovar were formed on the heating element via solder (90% by weight of tin / 10% by weight of lead).

(14) Next, a plurality of thermocouples for temperature control were buried in the recesses to obtain a wafer prober 501. In each of the examples, the sintered body could be easily taken out of the crucible.

[0176]

As described above, in the method for manufacturing a ceramic substrate according to the present invention, a polygonal laminated body of green sheets is fired to produce a polygonal plate-shaped sintered body. Processing is relatively easy, cutting can be performed in a short time, and manufacturing cost can be reduced. Further, the crucible can be easily taken out of the sintered body.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views schematically showing a part of a manufacturing process in a method of manufacturing a ceramic substrate according to the present invention.

FIGS. 2D to 2F are cross-sectional views schematically showing a part of the manufacturing process in the method for manufacturing a ceramic substrate of the present invention.

FIG. 3 is a cross-sectional view schematically showing one example of an electrostatic chuck manufactured by the manufacturing method of the present invention.

4 is a cross-sectional view of the electrostatic chuck shown in FIG. 3, taken along the line AA.

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

FIG. 6 is a cross-sectional view schematically showing one example of an electrostatic chuck manufactured by the manufacturing method of the present invention.

FIG. 7 is a cross-sectional view schematically showing one example of an electrostatic chuck manufactured by the manufacturing method of the present invention.

FIG. 8 is a cross-sectional view schematically showing one example of an electrostatic chuck manufactured by the manufacturing method of the present invention.

FIG. 9 is a horizontal sectional view schematically showing the shape of an electrostatic electrode constituting an electrostatic chuck manufactured by the manufacturing method of the present invention.

FIG. 10 is a horizontal sectional view schematically showing the shape of an electrostatic electrode constituting an electrostatic chuck manufactured by the manufacturing method of the present invention.

FIG. 11 is a cross-sectional view schematically showing a state where the electrostatic chuck manufactured by the manufacturing method of the present invention is fitted into a supporting container.

FIG. 12 is a partially enlarged cross-sectional view schematically showing a part of a ceramic heater manufactured by the manufacturing method of the present invention.

FIG. 13 is a sectional view schematically showing a wafer prober manufactured by the manufacturing method of the present invention.

FIG. 14 is a plan view of the wafer prober shown in FIG.

FIG. 15 is a sectional view taken along line AA of the wafer prober shown in FIG.

FIGS. 16A and 16B are explanatory views schematically showing a method for manufacturing a ceramic substrate using a guide plate.

FIGS. 17A to 17D are cross-sectional views schematically showing a conventional method for manufacturing a ceramic substrate.

[Explanation of symbols]

 1, 61, 91 Ceramic substrate 2, 22, 32a, 32b Chuck positive electrode electrostatic layer 3, 23, 33a, 33b Chuck negative electrode electrostatic layer 2a, 3a Semicircular portion 2b, 3b Comb portion 4 Ceramic dielectric film 5 , 62, 93 Resistance heating element 6, 18, 25, 63 External terminal 7 Metal wire 8 Peltier element 9 Silicon wafer 16, 17, 69 Through hole 25a Metal coating layer 35, 36 Bag hole 41 Support container 42 Refrigerant outlet 43 Suction Port 44 Refrigerant injection port 45 Insulating material 50 Green sheet 60 Ceramic heater 61a Heating surface 61b Bottom 64 Bottomed hole 65 Through hole 66 Lifter pin 71 Crucible 72 Plated sintered body 90 Wafer prober 92 Chuck top conductor layer 95 Guard electrode 96 Ground Electrode 97 Groove 98 Suction hole 101, 201, 301, 401 Electrostatic Jack 500 green sheet laminate 700 polygon laminate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G001 BA09 BA36 BB09 BB36 BC35 BC42 BC73 BD38 BE32 4M106 DD01 DD10 5F031 HA02 HA03 HA17 HA18 HA37

Claims (2)

[Claims] 1. A method for manufacturing a circular or elliptical ceramic substrate in plan view having a conductor layer provided on its surface or inside, comprising the steps of manufacturing an unsintered polygon, and firing the polygon. And a sintered body manufacturing step of manufacturing a polygonal plate-shaped sintered body, and a cutting step of cutting the plate-shaped sintered body to produce a circular or elliptical ceramic substrate in plan view. A method for manufacturing a ceramic substrate, comprising: 2. A method for manufacturing a circular or elliptical ceramic substrate in a plan view having a conductor layer provided on the surface or inside thereof, comprising: forming a rectangular green sheet;
A printing step of printing a conductor paste on the green sheet, a laminate production step of laminating another green sheet on the green sheet on which the conductor paste is printed to produce a green sheet laminate, and A cutting step of producing a polygonal laminate by performing a cutting process; a sintered body production step of firing the polygonal laminate to produce a polygonal plate-like sintered body; and And a cutting process for producing a ceramic substrate having a circular shape or an elliptical shape in plan view by performing a cutting process of the united body.