JP2003300785A - Ceramic jointed body and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic jointed body in which a ceramic substrate is tightly jointed with a ceramic body and which is able to surly protect external terminals, or the like, arranged on the ceramic substrate from a corrosive gas. <P>SOLUTION: In the ceramic jointed body, the ceramic body is jointed to the bottom surface of the ceramic substrate in which a conductor is provided on the surface or at the inside of the ceramic substrate, and the ceramic substrate contains carbon in such a manner that the concentration at the inside of the substrate of the carbon is higher than that in the vicinity of the surface of the substrate. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic bonded body which is used for a hot plate (ceramic heater), an electrostatic chuck, a susceptor, etc. and has a conductor provided on the surface or inside thereof, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In semiconductor manufacturing / inspection equipment including etching equipment and chemical vapor deposition equipment, heaters and electrostatic chucks using metal base materials such as stainless steel and aluminum alloy have been conventionally used. Has been used.

However, such a metal heater is
There were the following problems. First of all, because it is made of metal,
The thickness of the heater plate should be as thick as about 15 mm. This is because, in a thin metal plate, warping, distortion, etc. may not occur due to thermal expansion due to heating, and the silicon wafer placed on the metal plate may be damaged or tilted. However, when the thickness of the heater plate is increased, there is a problem that the weight of the heater becomes heavy and the heater becomes bulky.

Further, the temperature of a surface (hereinafter referred to as a heating surface) for heating an object to be heated such as a silicon wafer is controlled by changing the voltage and the amount of current applied to the resistance heating element. Since it is thick, the temperature of the heater plate does not quickly follow changes in voltage and current amount, and there is a problem that temperature control is difficult.

Therefore, aluminum nitride, which is a non-oxide ceramic having high thermal conductivity and high strength, is used as a substrate for a heater or the like in semiconductor manufacturing / inspection equipment,
A hot plate has been proposed in which a resistance heating element and a through hole made of tungsten are formed in the aluminum nitride substrate, and a nichrome wire is brazed to these as an external terminal.

Since such a hot plate uses an aluminum nitride substrate having high mechanical strength even at high temperatures, the thickness of the aluminum nitride substrate can be reduced to reduce the heat capacity, and as a result, the voltage can be reduced. The temperature of the aluminum nitride substrate can be quickly made to follow the change of the current amount.

Further, in such a hot plate, as in the ceramic bonded body described in Japanese Patent No. 2783980, a solution containing a sintering aid is applied to the bonding surface of a cylindrical ceramic to form a disk shape. By contacting the ceramic with the ceramic and heating, the ceramic particles grow at the interface so as to extend to both sides of the interface, and the cylindrical ceramic and the disk-shaped ceramic are joined, and the reaction used in the semiconductor manufacturing process is performed. Means have been taken to protect the wiring such as external terminals from volatile gas and halogen gas.

[0008]

However, in the above-mentioned ceramic bonded body, the carbon compounded in the ceramic substrate for the purpose of hiding the electrodes and utilizing the black body radiation is uniformly distributed over the entire ceramic substrate. Since it is distributed, when the ceramic body coated with the solution containing the sintering aid on the joint surface is brought into contact with the ceramic substrate and heated, carbon existing near the surface of the ceramic substrate becomes impurities, and In some cases, the grain growth of ceramic particles at the interface was hindered and the bonding was insufficient. As a result of diligent research into this cause, the presence of carbon hinders the diffusion of the sintering aid, or the sintering aid is reduced by carbon and does not function as a sintering aid, resulting in unsatisfactory bonding. It was found to be sufficient.

The inclusion of carbon in the ceramic substrate is indispensable from the viewpoint of concealing the electrodes, utilization of black body radiation, and the like, and further suppresses reduction in volume resistivity and thermal conductivity of the ceramic substrate at high temperatures. Therefore, using a ceramic substrate that does not contain carbon,
It was practically difficult to manufacture a ceramic bonded body.

The present invention has been made to solve the above-mentioned problems, and is intended for a case where the ceramic bonded body is continuously exposed to a reactive gas or a halogen gas for a long period of time, or a case where temperature rising / falling is repeated. Even if it exists, it is an object of the present invention to realize a ceramic bonded body having a high bonding strength between the ceramic substrate and the ceramic body and excellent durability.

[0011]

According to the present invention, a ceramic substrate having a conductor provided on the surface or inside thereof is provided on the bottom surface of the ceramic substrate.
A ceramic joined body in which a ceramic body is joined,
The ceramic substrate contains carbon, and the concentration of carbon near the surface of the ceramic substrate is lower than the concentration of carbon inside the ceramic substrate.

According to the ceramic bonded body of the present invention, the concentration of carbon contained in the ceramic substrate in the vicinity of the surface of the ceramic substrate is lower than that in the inside of the ceramic substrate. When a solution containing a sintering aid is applied to the joint surface, the ceramic substrate is brought into contact with the solution, and the mixture is heated,
At the joint surface of the ceramic body and the ceramic substrate,
Since the diffusion of the sintering aid is not hindered by the presence of carbon, and the sintering aid is not reduced by carbon, good grain growth of ceramic particles occurs at the interface between the two, and It is possible to firmly bond the ceramic substrate and the ceramic body.

Further, in the ceramic joined body of the present invention, the carbon concentration is low only near the surface of the ceramic substrate, and a sufficient carbon concentration is secured inside the ceramic substrate. The advantages of the addition of carbon, such as hiding and the use of black body radiation, are not affected at all, and a ceramic joined body having excellent heating characteristics can be obtained. Here, the vicinity of the surface of the ceramic substrate means a region from the surface of the ceramic substrate to 10% of the thickness of the ceramic substrate, and the inside of the ceramic substrate means the vicinity of the surface of the ceramic substrate out of the entire ceramic substrate. It means the area excluding.

The conductor is a resistance heating element, and the ceramic bonded body of the present invention preferably functions as a hot plate. This is because it is particularly desirable that the ceramic joined body of the present invention be used at a high temperature. The resistance heating element may be formed in a layered form or a linear body.

The conductor is an electrostatic electrode, and the ceramic bonded body of the present invention preferably functions as an electrostatic chuck. This is because the electrostatic chuck is often used in a corrosive atmosphere, and by using the ceramic bonded body of the present invention as an electrostatic chuck, it can be suitably protected from corrosive gas.

Further, the ceramic bonded body of the present invention is obtained by firing a ceramic molded body containing ceramic powder and carbon or a material serving as a carbon raw material to prepare a ceramic substrate containing carbon in a substantially uniform concentration. The substrate is subjected to carbon non-uniformity treatment under atmospheric pressure, 1800 to 2000 ° C. under N ₂ gas atmosphere, and then the above ceramic body obtained by applying a solution containing a sintering aid to the bonding surface is applied to the bottom surface of the ceramic substrate. It is characterized in that the ceramic substrate and the ceramic body are joined by bringing them into contact with each other and heating. At this time, the reactions shown in the following chemical formulas (1) and (2) occur, and carbon on the surface of the ceramic substrate is removed.

AlN + 3C + N ₂ + Y ₂ O ₃ → AlN + 3CO ↑ + 2YN (1)

2YN + Al ₂ O ₃ → Y ₂ O ₃ + 2AlN (2)

When a molded body containing a ceramic powder such as aluminum nitride and a carbon raw material such as an acrylic resin is fired by a usual method, carbon diffuses in the ceramic substrate and the entire ceramic substrate Although the carbon concentration becomes almost uniform, the carbon concentration inside the ceramic substrate is largely changed by further treating the obtained ceramic substrate under normal pressure, 1800 to 2000 ° C., and N ₂ gas atmosphere. Without
Only the carbon concentration near the surface of the ceramic substrate can be reduced.

Further, yttria, ytterbium oxide, etc. are added to the ceramic substrate as a sintering aid, and these sintering aids move to the vicinity of the surface of the ceramic substrate with sintering. Therefore, carbon in the vicinity of the surface of the ceramic substrate is oxidized by oxygen in the sintering aid near the surface of the ceramic substrate, and the carbon becomes a gas such as carbon monoxide or carbon dioxide and escapes from the surface of the ceramic substrate. It is considered that, as a result, the carbon concentration near the surface of the ceramic substrate decreases. In addition, the step of heating under the above conditions (hereinafter,
In the non-uniform carbon treatment), by introducing a trace amount of oxygen in addition to the N ₂ gas, the oxidation of carbon near the surface of the ceramic substrate is further promoted, and the carbon concentration near the surface of the ceramic substrate is further reduced. Can be made.

Further, the carbon non-uniformizing step does not require a special step or apparatus and can be performed only by heating the ceramic substrate under a certain condition, and therefore can be performed relatively easily. it can. It should be noted that such carbon non-uniformity treatment will be described in detail in the description of the manufacturing method of the present invention.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the embodiments. The present invention is not limited to this description.

The ceramic bonded body of the present invention is a ceramic bonded body in which a ceramic body is bonded to the bottom surface of a ceramic substrate provided with a conductor on the surface or inside thereof, and the ceramic substrate contains carbon. The carbon concentration near the surface of the ceramic substrate is lower than the carbon concentration inside the ceramic substrate. An embodiment of a ceramic bonded body of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view schematically showing a hot plate which is an example of the ceramic bonded body of the present invention, and FIG. 2 is a plan view schematically showing the hot plate shown in FIG. Further, FIG. 3 is a cross-sectional view schematically showing the distribution state of carbon in the entire ceramic substrate.

As shown in FIG. 1, this hot plate 1
In No. 0, the cylindrical ceramic body 17 is directly bonded near the center of the bottom surface 11b of the disk-shaped ceramic substrate 11. Further, since the cylindrical ceramic body 17 is formed so as to be in close contact with the bottom plate (not shown) of the support container, the inside and outside of the ceramic body 17 are completely separated.

Further, in FIG. 3, in the ceramic substrate 11, a region having a high carbon concentration is darkened, and a region outside the dark portion has a low carbon concentration. In FIG. 3, the tone is clearly changed between the high carbon concentration portion and the low carbon concentration portion, but in reality, the carbon concentration is the lowest near the surface of the ceramic substrate 11, and as it goes inward. It is gradually increasing, and when it reaches a certain depth, the concentration is almost constant. Therefore, when the solution containing the sintering aid is applied to the bonding surface 17a of the ceramic body 17 and brought into contact with the bottom surface 11b of the ceramic substrate 11 and the bonding is performed by heating, the ceramic body 17 of the ceramic substrate 11 is joined. The carbon concentration is low in the vicinity of the joint surface with. Therefore, at the bonding interface between the ceramic substrate 11 and the ceramic body 17, the relative concentration of the ceramic particles becomes high, so that the grain growth of the ceramic particles occurs in such a manner that the sintering proceeds, and the ceramic particles form the bonding interface. Since the structure is such that the ceramic substrate 11 and the ceramic body 17 penetrate each other, the ceramic substrate 11 and the ceramic body 17 can be firmly bonded to each other.

The carbon concentration is almost constant in the portion of the ceramic substrate 11 excluding the vicinity of the surface. As described above, since a sufficient carbon concentration is secured inside the ceramic substrate 11, there is no influence on the advantages of the addition of carbon such as concealment of the electrode portion and use of black body radiation, and the heating characteristics are excellent. It can be a hot plate 10.

Further, as shown in FIG. 1, the resistance heating element 12
A conductor circuit 18 extending toward the center of the ceramic substrate 11 is formed between the bottom surface 11b and the bottom surface 11b, and the resistance heating element end portion 12a and one end of the conductor circuit 18 are connected via a via hole 16. ing.

This conductor circuit 18 has the end portion 12 of the resistance heating element.
Is formed to extend to the central portion, and a through hole 13 'is formed in the inside of the ceramic substrate 11 immediately below the other end of the conductor circuit 18 extending to the vicinity of the inside of the ceramic body 17. Has been done. Further, when the end portion 12 of the resistance heating element is inside the ceramic body 17, a via hole or a conductor circuit is not necessary, so the through hole 13 is formed directly on the end portion of the resistance heating element.

Further, the through holes 13 and 13 'have
A screw hole having an opening is formed on the bottom surface thereof, and an external terminal 23 having a screw portion at the tip is screwed into this screw hole. A socket 31 having a conductive wire 230 is attached to these external terminals 23, and the conductive wire 230 is pulled out from a through hole formed in a bottom plate (not shown) to a power source (not shown). ) Is connected with.

On the other hand, a temperature measuring element 21 such as a thermocouple having a lead wire 210 is inserted into the bottomed hole 14 formed in the bottom surface 11b of the ceramic substrate 11, and a heat resistant resin, ceramic (silica gel, etc.) is used. Are sealed. The lead wire 210 is inserted through the inside of the protective tube and is drawn out to the outside through a through hole (not shown) formed in the bottom plate of the support container, and the inside of the insulator is also isolated from the outside. Further, a through hole 15 for inserting the lifter pin 8 is provided in a portion near the center of the ceramic substrate 11.

The lifter pin 8 is designed so that an object to be processed such as a silicon wafer can be placed on the lifter pin 8 and moved up and down, whereby the silicon wafer 9 is transferred to a transfer machine (not shown) or transferred. While receiving the silicon wafer from the machine, the silicon wafer 9 is placed on the heating surface 11a of the ceramic substrate 11 to be heated, or the silicon wafer is supported and heated while being separated from the heating surface 11a by 50 to 2000 μm. Is able to.

A state in which a through hole or a recess is provided in the ceramic substrate 11 and a support pin having a pointed or hemispherical tip is inserted into the through hole or the recess, and then the support pin is slightly projected from the ceramic substrate 11. The heating surface 1 is fixed by fixing it with
You may heat in the state spaced apart from 1a by 50-2000 micrometers.

Further, inside the ceramic substrate 11, as shown in FIG. 2, the resistance heating element 12a, which is an arc pattern repeatedly formed on the outermost periphery of the ceramic substrate 11 so as to draw a part of a concentric circle, is formed. .About.12d are arranged, and resistance heating elements 12e to 12h, which are concentric circular patterns partially cut, are arranged inside thereof.

The outermost resistance heating element 12a is formed by repeatedly forming arc-shaped patterns obtained by dividing a concentric circle into four in the circumferential direction, and the ends of adjacent arcs are connected by bending lines to form a series of circuits. ing. Then, four circuits of the resistance heating elements 12a to 12d, which have the same pattern as this, are formed close to each other so as to surround the outer circumference, and form an annular pattern as a whole.

Further, the end portions of the resistance heating elements 12a to 12d are formed inside the annular pattern, so that the end portion of the outer circuit is extended toward the inner side. A via hole 16 is formed immediately below the ends of the resistance heating elements 12a to 12d, and a conductor circuit 18 extending from the via hole 16 to the vicinity of the center is formed.

Resistance heating elements 12a-1 formed on the outermost periphery
Inside the 2d, resistance heating elements 12e to 12h each having a circuit of a concentric pattern, a part of which is cut, are formed. In the resistance heating elements 12e to 12h, a series of circuits are configured by sequentially connecting the ends of adjacent concentric circles with resistance heating elements formed of a straight line, and the ends are formed of the cylindrical ceramic body 17. When it is not located in the portion corresponding to the inside, the via hole 16 is formed immediately below it, and the conductor circuit 18 extending from the via hole 16 to the vicinity of the center is formed.

Further, the resistance heating elements 12a to 12d, 12
Between e, 12f, 12g, and 12h, there is a strip (annular shape)
The heating element non-formation area of is provided, and in the center part,
A circular heating element non-forming area is provided.

Therefore, as a whole, annular resistance heating element forming regions and heating element non-forming regions are alternately formed from the outside to the inside, and these regions are formed in the size (caliber of the ceramic substrate). ), The thickness, etc., the temperature of the heating surface can be made uniform by appropriately setting.

Such a hot plate 10 is usually
It is used in a state of being arranged in a support container. FIG. 4 is a cross-sectional view schematically showing how the hot plate 10 is arranged in such a supporting container.

In the hot plate unit 100, the hot plate 10 is fitted into the substantially cylindrical support container 20 via the heat insulating ring 24 having an L-shaped cross section.
In addition, the support container 20 has a substantially cylindrical outer frame portion 27 and a disc-shaped bottom plate 22 that are integrally formed. The support container 20 includes a substantially cylindrical outer frame portion 27 and an outer frame portion 27.
It is composed of a disc-shaped bottom plate 22 fixed to the bottom plate receiving portion 27c at the inner lower portion, and an inner bottom plate 23 fixed to the middle bottom plate receiving portion 27b of the inner middle step of the outer frame portion 27. A ring-shaped substrate receiving portion 27 a for supporting the heat insulating ring 24 is provided on the inner upper portion of the outer frame portion 27. The hot plate 10 is inserted through the heat insulating ring 24 and is fixed by the fixing metal fitting 28a via the bolt 28b screwed into the substrate receiving portion 27a. That is, the fixing member 28a is attached to the bolt 28b, and the hot plate 10 is fixed by being pressed by the fixing member 28a.

The bottom plate 22 is provided for the purpose of heat shield and the like, and the bottom plate 22 is provided with a refrigerant introduction pipe 26 so that a refrigerant for forced cooling or the like can be introduced into the inside of the support container 20. The through hole 22a for discharging the introduced cooling medium for forced cooling and the like is formed. Further, the hot plate 10 and the bottom plate 22 of the support container 20 are supported and fixed so as to be substantially parallel to each other. Therefore, it is possible to cool the ceramic substrate 11 by energizing the hot plate unit 100 to heat it to heat the silicon wafer 9 to a predetermined temperature and then blowing the refrigerant through the refrigerant introducing pipe 26.

A through hole is formed in the inner bottom plate 23 so as not to interfere with the refrigerant introduction pipe 26 fixed to the bottom plate 22, the guide pipe 25 for protecting the lifter pin 8, and the like.

Further, as described above, in this hot plate 10, the ceramic body 17 is joined to the bottom surface 11b of the ceramic substrate 11, and the ceramic body 17 is formed up to the bottom plate 22 of the support container. The inside and the outside are completely isolated.

Therefore, by protecting the wiring 230 drawn out from the through hole of the bottom plate 22 with the tubular member, the periphery of the hot plate 10 becomes an atmosphere containing reactive gas, halogen gas, etc. Even if gas or the like easily enters the inside of the support container, the wiring or the like inside the ceramic body 17 does not corrode. The wiring 210 from the temperature measuring element 21 is also protected by the protective tube 140, and therefore does not corrode.

Further, by injecting an inert gas or the like slowly into the ceramic body 17 so that the reactive gas or the halogen gas does not flow into the ceramic body 17, the wiring 230 is more reliably corroded. Can be prevented.

The above-mentioned hot plate 10 is a device in which only a resistance heating element is provided inside the ceramic substrate 11, whereby an object to be processed such as a silicon wafer is placed on or separated from the surface of the ceramic substrate 11. Hold
It can be heated to a predetermined temperature or washed.

Furthermore, since the ceramic body 17 also has a function of firmly supporting the ceramic substrate 11,
Even when the ceramic substrate 11 is heated to a high temperature, it is possible to prevent the ceramic substrate 11 from warping due to its own weight. As a result, damage to an object to be processed such as a silicon wafer is prevented and the object to be processed is heated to a uniform temperature. Can also be heated to.

FIG. 5 is a bottom view schematically showing another example of the hot plate of the present invention, and FIG. 6 is a plan view of the hot plate shown in FIG. As shown in FIGS. 5 and 6, the ceramic substrate 51 is formed in a disc shape, and a plurality of ceramic bodies 57 are bonded to the ceramic substrate 51 near the outer periphery of the bottom surface 51 b.

In the hot plate 50 as well, as in the hot plate 10 shown in FIG. 1, the carbon concentration is high inside the ceramic substrate 51, but near the surface of the ceramic substrate 51, inside the ceramic substrate 51. The concentration is lower than that of

Therefore, the joint surface 57a of the ceramic body 57 is formed.
When a solution containing a sintering aid is applied to, the ceramic substrate 51 is brought into contact with the solution, and the bonding is performed by heating,
The carbon concentration is low in the vicinity of the bonding surface of the ceramic substrate 51 with the ceramic body 57. As a result, the relative concentration of the ceramic particles increases at the bonding interface between the ceramic substrate 51 and the ceramic body 57, so that good grain growth of the ceramic particles occurs, and the ceramic particles penetrate into each other beyond the bonding interface. Therefore, the ceramic substrate 51 and the ceramic body 57 can be firmly bonded to each other.

On the bottom surface 51b of the ceramic substrate 51, as shown in FIG. 6, the resistance heating element 5 is an arc pattern which is repeatedly formed so as to draw a part of a concentric circle.
2a to 52d are arranged adjacent to each other, and these circuits are combined so that the temperature on the heating surface 51a is uniform. The end portion of the resistance heating element 52 is provided near the outer peripheral portion of the ceramic substrate 51, and accordingly, the external terminal 63 is also formed near the outer peripheral portion of the ceramic substrate 51. In addition, the resistance heating element 52,
A metal coating layer 520 is formed in order to prevent oxidation and the like. An external terminal 63 is brazed to the end of the resistance heating element 52, and the external terminal 63 is
The conductive wire 630 is connected via the socket 31.

Further, a bottomed hole 54 for inserting a temperature measuring element is formed in the bottom surface 51b of the ceramic substrate 51,
Inside the bottomed hole 54, the temperature measuring element 21 such as a thermocouple is embedded. In addition, a through hole 55 for inserting the rod-shaped lifter pin 8 is provided in a portion near the center.
Are provided (see FIG. 5). The description of the lifter pin 8, the temperature measuring element 21, and the like that compose the hot plate 50 is the same as that of the hot plate 10, and thus the description thereof is omitted.

Next, members constituting the hot plate which is one form of the ceramic bonded body of the present invention will be described.

The ceramic substrate forming the hot plate of the present invention contains carbon for the purpose of concealing the electrodes and utilizing black body radiation, and its concentration is higher than that in the vicinity of the surface of the ceramic substrate. Higher concentration inside. Here, the vicinity of the surface of the ceramic substrate means a region from the surface of the ceramic substrate to 10% of the thickness of the ceramic substrate, and the inside of the ceramic substrate means the vicinity of the surface of the ceramic substrate out of the entire ceramic substrate. It means the area excluding. However, as described above, the carbon concentration in the vicinity of the surface is the smallest, and the carbon concentration gradually increases toward the inside, rather than the clear difference in the concentration between the surface of the ceramic substrate and the region excluding it. When reaching a certain depth, the concentration becomes almost constant. The region where the concentration is almost constant is 3 from the surface of the ceramic substrate to the thickness of the ceramic substrate.
The area is 0 to 70%.

The concentration of carbon near the surface of the ceramic substrate is preferably 80% or less of the concentration inside the ceramic substrate. This is because if the carbon concentration exceeds 80% of the internal concentration of the ceramic substrate, the effect of the present invention that the ceramic substrate and the ceramic body are firmly bonded cannot be exhibited sufficiently.

The concentration of carbon in the portion of the ceramic substrate where the concentration is almost constant is 200 to
It is preferably 5000 ppm. If it is less than 200 ppm, it cannot be said that it is black, and the brightness exceeds N6. On the other hand, if the addition amount exceeds 5000 ppm, the sinterability of the ceramic particles constituting the ceramic substrate is lowered. The unit of carbon concentration is ppm
Means mass parts per million.

There are amorphous carbon and crystalline carbon. Amorphous carbon can suppress a decrease in volume resistivity of a substrate at a high temperature, and crystalline carbon does not Since the decrease in the thermal conductivity of the substrate at a high temperature can be suppressed, the type of carbon can be appropriately selected according to the purpose of the substrate to be manufactured.

Amorphous carbon is, for example, C, H or O.
It can be obtained by calcining a hydrocarbon consisting only of saccharides, preferably sugar, in air, and graphite powder or the like can be used as the crystalline carbon.
Carbon can be obtained by thermally decomposing an acrylic resin in an inert gas atmosphere and then heating and pressing it. However, by changing the acid value of this acrylic resin, the crystalline (non-crystalline) ) Can be adjusted.

That is, an acrylic resin having an acid value of 5 to 17 KOHmg / g is mixed with a ceramic raw material, which is then molded, and then an inert gas atmosphere (nitriding gas, argon gas).
It is pyrolyzed and carbonized below 350 ° C. Then, after thermally decomposing these acrylic resins, they are heated and pressed to obtain a sintered body. The reason why the crystallinity is lowered by using such an acrylic resin is not clear, but the acid value is 5 to 17 KOHmg / g.
It is presumed that carbonization proceeds while the amorphous skeleton of the acrylic resin remains, because the acrylic resin is less likely to be thermally decomposed and carbonized. Furthermore, since the acrylic resin having an acid value of 5 to 17 KOHmg / g is difficult to thermally decompose, it is desirable to adjust the blending amount to 2.5 to 8% by weight based on the raw material powder. The acrylic resin having an acid value of 5 to 17 KOHmg / g is -30.
It is desirable to have a Tg point of ℃ to -10 ℃. The weight average molecular weight is preferably 1 to 50,000.

In addition to this, the acid value is 0.3 to 1.0.
There is also a method in which an acrylic resin of KOH mg / g is mixed with a ceramic raw material, which is molded, and then decomposed and carbonized at a heat temperature of 350 ° C. or higher in an inert gas atmosphere (nitriding gas, argon gas). Then, after the acrylic resin is thermally decomposed, it is heated and pressed to obtain a sintered body. Although the reason why carbon having both crystallinity and amorphousness can be obtained by using such an acrylic resin is not clear, the acid value is 0.3 to 1.0 KOHm.
It is presumed that the acrylic resin of g / g is likely to be thermally decomposed and easily carbonized, so that carbonization proceeds while cutting the amorphous skeleton of the acrylic resin, and thus the crystallinity is likely to increase. There is. Furthermore, the acid value is 0.3 to
Since 1.0 KOHmg / g of acrylic resin is easily decomposed by heat, it is desirable to adjust the compounding amount to 8 to 20% by weight based on the raw material powder. The acid value is 0.3-1.0K
OHmg / g acrylic resin is T of 40 ℃ -60 ℃
It is desirable to have g points. The weight average molecular weight is 1 to
It is preferably 50,000.

Further, the acrylic resin is acrylic acid,
A copolymer composed of any one or more of acrylic acid esters and / or any one or more of methacrylic acid or methacrylic acid esters is desirable. As a commercial product of such an acrylic resin, Kyoeisha KC-600 is available.
There is a series. This series has an acid value of 10-17KO
All of Hmg / g are available. In addition, S manufactured by Mitsui Chemicals, Inc.
There is also the A-545 series, which has an acid value of 0.
5 to 1.0 KOHmg / g is available.

The brightness of the ceramic substrate 11 is JIS Z.
The value based on the standard of 8721 is preferably N6 or less. This is because those having such brightness are excellent in radiant heat amount and concealing property. Further, the hot plate constituted by such a ceramic substrate enables accurate surface temperature measurement by a thermoviewer.

Here, the lightness N is such that the ideal lightness of black is 0 and the ideal lightness of white is 10, and the brightness of that color is between the lightness of black and the lightness of white. Each color is divided into 10 so that the perception of is equal to each other, and is displayed by symbols N0 to N10. And the actual measurement is N0-N
The color chart corresponding to 10 is compared. In this case, the first decimal place is 0 or 5. The ceramic substrate 11 having such characteristics has 100 to 500 carbon in the substrate.
It is obtained by containing 0 ppm.

In the ceramic bonded body of the present invention, the ceramic forming the ceramic substrate is preferably, for example, a nitride ceramic, a carbide ceramic or an oxide ceramic. Nitride ceramics, carbide ceramics, and oxide ceramics have a thermal expansion coefficient smaller than that of metals, and their mechanical strength is significantly higher than that of metals. Therefore, even if the thickness of the ceramic substrate is reduced, it may warp due to heating. , Not distorted. Therefore, the ceramic substrate can be made thin and light. Furthermore, since the ceramic substrate has high thermal conductivity and the ceramic substrate itself is thin, the surface temperature of the ceramic substrate quickly follows the temperature change of the resistance heating element. That is, the surface temperature of the ceramic substrate can be controlled by changing the temperature of the resistance heating element by changing the voltage and current values.

Examples of the above nitride ceramics include:
Examples thereof include aluminum nitride, silicon nitride, boron nitride, titanium nitride and the like. These may be used alone or 2
You may use together 1 or more types.

Examples of the above-mentioned carbide ceramics include silicon carbide, zirconium carbide, titanium carbide, tantalum carbide, tungsten carbide and the like. These may be used alone or in combination of two or more.

Further, as the above oxide ceramic,
Examples thereof include alumina, zirconia, cordierite, mullite and the like. These may be used alone,
You may use 2 or more types together.

Among these, aluminum nitride, which is a nitride ceramic, is most preferable. Thermal conductivity is 180
This is because it has the highest W / m · K and is excellent in temperature followability.

The ceramic substrate may contain a sintering aid. Examples of the sintering aid include, for example,
Examples thereof include alkali metal oxides, alkaline earth metal oxides and rare earth oxides. Among these sintering aids,
CaO, Y ₂ O ₃ , Na ₂ O, Li ₂ O and Rb ₂ O are preferable. The content of these is 0.1 to 20% by weight.
Is preferred. It may also contain alumina.

The ceramic substrate 11 preferably has a disc shape as shown in FIG. 2, and its diameter is 200 mm.
The above is preferable, and 250 mm or more is optimal. This is because the disk-shaped ceramic substrate 11 is required to have a uniform temperature, but a substrate having a larger diameter tends to have a non-uniform temperature.

The thickness of the ceramic substrate 11 is preferably 50 mm or less, more preferably 20 mm or less. Also, 1
~ 5 mm is optimal. This is because if the thickness is too thin, warpage is likely to occur when heating at high temperatures, while if it is too thick, the heat capacity becomes too large and the temperature raising / lowering characteristics deteriorate.

The porosity of the ceramic substrate 11 is 0.
Alternatively, it is preferably 5% or less. The porosity is measured by the Archimedes method. This is because it is possible to suppress the decrease in thermal conductivity at high temperatures and the occurrence of warpage.

The pattern of the resistance heating element 12 is shown in FIG.
In addition to the concentric circular pattern and the arcuate pattern obtained by dividing the concentric circular shape, a spiral shape, an eccentric circular shape, a combination of a concentric circular shape and a bent line shape, and the like can be given. The resistance heating element 12 preferably has a thickness of 1 to 50 μm and a width of 5 to 20 μm.
Is desirable.

The resistance value can be changed by changing the thickness or width of the resistance heating element 12, but this range is the most practical. The resistance value of the resistance heating element 12 increases as the thickness thereof decreases and the width thereof decreases.

The resistance heating element 12 has a rectangular cross section, an elliptical cross section,
It may have a spindle shape or a kamaboko shape, but it 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 transfer to the heating surface can be increased and the temperature distribution on the heating surface is less likely to occur. In addition,
The resistance heating element 12 may have a spiral shape.

In the hot plate 10, the number of circuits consisting of the resistance heating elements 12 is not particularly limited as long as it is 1 or more, but it is desirable to form a plurality of circuits in order to uniformly heat the heating surface. .

When the resistance heating element 12 is formed inside the ceramic substrate 11, its formation position is not particularly limited, but at least one layer is formed at a position from the bottom surface of the ceramic substrate 11 to 60% of its thickness. Is preferred. This is because the heat diffuses while the heat propagates to the heating surface, and the temperature on the heating surface tends to be uniform.

The resistance heating element 1 is provided inside the ceramic substrate 11.
When forming 2, the conductor paste made of metal or conductive ceramic is preferably used. That is, when the resistance heating element 12 is formed inside the ceramic substrate 11,
After the conductor paste layer is formed on the green sheet, the green sheets are laminated and fired to produce the resistance heating element 12 inside.

The above-mentioned conductor paste is not particularly limited, but it is preferable that the conductor paste contains metal particles or a conductive ceramic to secure conductivity, and contains a resin, a solvent, a thickener and the like.

As the metal particles, for example, noble metals (gold, silver, platinum, palladium), lead, tungsten, molybdenum, nickel and the like are preferable. These may be used alone or in combination of two or more. This is because these metals are relatively difficult to oxidize and have a resistance value sufficient to generate heat.

As the above-mentioned conductive ceramic, for example,
Examples thereof include tungsten and molybdenum carbides.
These may be used alone or in combination of two or more. The particle size of these metal particles or conductive ceramic particles is preferably 0.1 to 100 μm. This is because if it is less than 0.1 μm and too fine, it is easily oxidized, while if it exceeds 100 μm, it becomes difficult to sinter and the resistance value increases.

Even if the shape of the metal particles is spherical,
It may be flaky. When these metal particles are used, they may be a mixture of the above-mentioned spherical material and the above-mentioned scaly material. When the metal particles are scaly particles or a mixture of spherical particles and scaly particles, it becomes easier to hold the metal oxide between the metal particles, and the resistance heating element 12 and the ceramic substrate 1
This is advantageous because it is possible to secure the adhesion to 1 and to increase the resistance value.

The resin used for the conductor paste is
For example, epoxy resin, phenol resin, etc. may be mentioned. Examples of the solvent include isopropyl alcohol and the like. Examples of the thickener include cellulose and the like.

The through holes 13, 13 'and the via holes 16 are made of a metal such as tungsten or molybdenum, or a carbide thereof, and have a diameter of 0.1 to 1.
0 mm is desirable. This is because it is possible to prevent cracks and distortions while preventing disconnection.

The material of the external terminal 23 is not particularly limited, and examples thereof include metals such as nickel and kovar. The size is not particularly limited because it is appropriately adjusted depending on the size of the ceramic substrate 11 used, the size of the resistance heating element 12, and the like, but the diameter of the shaft portion is 0.5 to 5 mm, and the length of the shaft portion is long. It is desirable that the length is about 1 to 10 mm. A socket having a conductive wire is attached to such an external terminal 23, and the conductive wire is connected to a power source or the like.

Further, a temperature measuring element such as a thermocouple having a lead wire is inserted into the bottomed hole 14 and sealed with a heat resistant resin, ceramic (silica gel or the like) or the like. This is because it is possible to control the temperature of the hot plate 10 according to the present invention by measuring the temperature of the resistance heating element 12 with a temperature measuring element such as the thermocouple and changing the voltage and current amount based on the data. .

The size of the joining portion of the lead wire of the thermocouple is preferably equal to or larger than the wire diameter of each lead wire, and 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 11a of the wafer is reduced. Examples of the thermocouple include K-type, R-type, B-type, E-type, J-type, and T-type thermocouples, as described in JIS-C-1602 (1980).

In addition to the above-mentioned thermocouple, as the temperature measuring means of the hot plate 10 according to the present invention, for example, a temperature measuring element such as a platinum resistance temperature detector or a thermistor can be mentioned, and an optical means such as a thermoviewer. There is also a temperature measuring means using.

When the above-mentioned thermoviewer is used, the temperature of the heating surface of the ceramic substrate 11 can be measured, and the temperature of the surface of an object to be heated such as a silicon wafer can be directly measured. The accuracy of temperature control is improved.

The horizontal sectional shape of the ceramic body in the hot plate of the present invention is not particularly limited, and examples thereof include a circular ring shape, an elliptical ring shape, and a polygonal shape. Of these, the annular shape is desirable. If the cross-sectional shape of the ceramic body is an annular shape, since there are no corners on its outer circumference, stress concentration due to heat or shock is unlikely to occur, and the shape of the ceramic substrate is usually a disk shape, This is because the ceramic substrate can be stably supported. Further, the ceramic body may have a columnar shape, a polygonal columnar shape, or the like. That is, the ceramic body does not have to have a cavity formed therein, and may have the interior filled with ceramic. When such a ceramic body is used, a resistance heating element formed on the ceramic substrate and a power source can be electrically connected by providing a through hole made of a conductive ceramic, a refractory metal, or the like inside. . In the ceramic body as described above, it is possible to increase the joint surface between the ceramic body and the ceramic substrate, so that they can be joined more firmly. Further, the ceramic body may have a shape having a plurality of through holes for inserting an external terminal, a wiring connecting the external terminal and a power source, or the like in a cylindrical or polygonal column-shaped member.

When the ceramic body has a cylindrical shape or a circular cross section, the outer diameter is 33 mm.
The above is desirable. Moreover, when the cross-sectional shape of the ceramic body is an annular shape, the inner diameter is preferably 30 mm or more. When it is less than 30 mm, it becomes difficult to firmly support the ceramic substrate, and when the ceramic substrate is heated to a high temperature, the ceramic substrate may warp due to its own weight.

When the ceramic body has an annular cross section, the thickness of the ceramic body is 3 to 20 mm.
Is desirable. If it is less than 3 mm, the ceramic body is too thin, resulting in poor mechanical strength.
There is a possibility that the ceramic body may be damaged by repeating the heating and cooling, and if it exceeds 20 mm, the thickness of the ceramic body is too thick, so that the heat capacity becomes large and the temperature rising rate may decrease. Because there is.

When the ceramic body is joined to the ceramic substrate having the resistance heating element formed on the bottom surface, the resistance heating element may cross the joint surface between the ceramic substrate and the ceramic body. In this case, it is desirable to form a recess corresponding to the shape of the resistance heating element on the joint surface of the ceramic body. As a result, the ceramic substrate and the ceramic body can be brought into close contact with each other without a gap, and these can be joined firmly.

As the ceramic forming the ceramic body, the same ceramics as the above-mentioned ceramic substrate can be used. The method of joining the ceramic body and the ceramic substrate will be described in detail later.

When the conductor formed inside the ceramic substrate of the present invention is an electrostatic electrode, the ceramic substrate functions as an electrostatic chuck. FIG. 7 is a vertical sectional view schematically showing such an electrostatic chuck.
FIG. 4 is a horizontal cross-sectional view schematically showing the vicinity of electrostatic electrodes formed on a substrate that constitutes an electrostatic chuck.

Semicircular chuck positive and negative electrode electrostatic layers 72a and 72b are arranged to face each other inside a ceramic substrate 71 which constitutes the electrostatic chuck 70, and a ceramic dielectric film is formed on these electrostatic electrodes. 74 are formed. In addition, the resistance heating element 720 is provided inside the ceramic substrate 71.
Is provided so that an object to be processed such as a silicon wafer can be heated. The ceramic substrate 7
An RF electrode may be embedded in 1 as required.

Further, a cylindrical ceramic body 77 is joined near the center of the bottom surface of the ceramic substrate 71. In the electrostatic chuck 70 as well, as in the hot plate 10 shown in FIG. 1, the carbon concentration is high inside the ceramic substrate 71. However, near the surface of the ceramic substrate 71, the carbon concentration is higher than that inside the ceramic substrate 71. And the concentration is low.

Therefore, the joint surface 77a of the ceramic body 77 is
When a solution containing a sintering aid is applied to, the ceramic substrate 71 is brought into contact with the ceramic substrate 71, and the bonding is performed by heating,
The carbon concentration is low in the vicinity of the joint surface of the ceramic substrate 71 with the ceramic body 77. As a result, the relative concentration of the ceramic particles increases at the bonding interface between the ceramic substrate 71 and the ceramic body 77, so that good grain growth of the ceramic particles occurs, and the ceramic particles penetrate into each other beyond the bonding interface. Therefore, the ceramic substrate 71 and the ceramic body 77 can be firmly joined.

The electrostatic electrode is made of a noble metal (gold, silver, platinum,
Palladium), lead, tungsten, molybdenum, nickel, or another metal, or tungsten, molybdenum carbide, or another conductive ceramic is preferable. These may be used alone or in combination of two or more.

As shown in FIGS. 7 and 8, the electrostatic chuck 70 includes electrostatic electrodes 72a and 7a in a ceramic substrate 71.
2b is formed, a through hole 73 is formed immediately below the ends of the electrostatic electrodes 72a and 72b, and a ceramic dielectric film 74 is formed on the electrostatic electrode 72, except that the hot plate 10 is formed. Is configured.

Further, through holes 73 and 730 are formed above the inside of the ceramic body 77, and these through holes 73 and 730 are formed by the electrostatic electrodes 72a and 7a.
2b, which is connected to the resistance heating element 720, and also has a bag hole 7
It is connected to an external terminal 760 inserted in 90, and a socket 750 having a conductive wire 731 is connected to one end of this external terminal 760. The conductive wire 731 is drawn out through a through hole (not shown).

Further, in the case of the resistance heating element 720 having an end portion outside the ceramic body 77, as in the case of the hot plate 10 shown in FIG. 1, the via hole 79, the conductor circuit 780 and the through hole 730 'are formed. Thus, the end portion of the resistance heating element 720 is extended inside the ceramic body 77 (see FIG. 7). Therefore, the external terminal 760 can be stored inside the ceramic body 77 by inserting and connecting the external terminal 760 into the bag hole 790 exposing the through hole 730 '.

When operating such an electrostatic chuck 70, a voltage is applied to each of the resistance heating element 720 and the electrostatic electrode 72. As a result, the electrostatic chuck 70
The silicon wafer placed thereon is heated to a predetermined temperature and electrostatically attracted to the ceramic substrate 71. The electrostatic chuck does not necessarily have to include the resistance heating element 720.

FIG. 9 is a horizontal cross-sectional view schematically showing electrostatic electrodes formed on the substrate of another electrostatic chuck. Inside the substrate 81, a chuck positive electrode electrostatic layer 82 including a semi-circular portion 82a and a comb tooth portion 82b, and a semi-circular portion 83a similarly.
And a chuck negative electrode electrostatic layer 83 including a comb tooth portion 83b are arranged so as to face each other so as to intersect the comb tooth portions 82b and 83b.

FIG. 10 is a horizontal sectional view schematically showing the electrostatic electrode formed on the substrate of another electrostatic chuck. In this electrostatic chuck, chuck positive electrode electrostatic layers 92a and 92b and chuck negative electrode electrostatic layers 93a and 93b having a shape obtained by dividing a circle into four are formed inside a substrate 91.
Further, the two chuck positive electrode electrostatic layers 92a and 92b and the two chuck negative electrode electrostatic layers 93a and 93b are formed so as to intersect 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.

Next, a method for manufacturing the ceramic joined body of the present invention will be described. The method for producing a ceramic joined body according to the present invention is a method of producing a ceramic substrate containing ceramic powder and carbon or a raw material for carbon to obtain a ceramic substrate containing carbon in a substantially uniform concentration. Substrate is normal pressure, 1800-200
After performing the carbon non-uniformization treatment at 0 ° C. under N ₂ gas atmosphere, the ceramic body having the bonding surface coated with the solution containing the sintering aid is brought into contact with the bottom surface of the ceramic substrate and heated. The ceramic substrate and the ceramic body are bonded together.

An example of the method for manufacturing the ceramic bonded body of the present invention will be described below with reference to FIG. 11 based on the above manufacturing method. 11 (a) to 11 (d)
FIG. 6 is a cross-sectional view schematically showing a part of a method for manufacturing a hot plate having a resistance heating element inside a ceramic substrate.

(1) Green Sheet Making Process First, a ceramic powder and yttria are mixed with a binder, a solvent and the like to prepare a paste, which is used to make a green sheet. Note that crystalline or amorphous carbon is added to the green sheet. Examples of the method of adding crystalline carbon include a method of directly adding graphite powder, and examples of the method of adding amorphous carbon include a method of thermally decomposing an acrylic resin or the like. Further, it is desirable that yttria is contained in the green sheet in an amount of 0.1 to 10% by weight. Furthermore, in the green sheet, in addition to the yttria, for example, CaO, Na ₂ O, Li ₂ O,
Rb ₂ O _{3 and the} like may be contained. This is because these compounds also function favorably as sintering aids.

Further, 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 the doctor blade method to obtain the green sheet 1.
Make 10. The thickness of the green sheet 110 is 0.
1-5 mm is preferable. Next, a portion 160 serving as a via hole for connecting the end portion of the resistance heating element and the conductor circuit.
And the portions 130 and 13 that will be through holes for connecting the conductor circuit and external terminals
A green sheet having 0 'is formed.

The through holes may be filled with the above paste containing carbon. This is because the carbon in the green sheet reacts with the tungsten and molybdenum filled in the through holes to form these carbides.

(2) Process of Printing Conductor Paste on Green Sheet A conductor paste containing a metal paste or a conductive ceramic for forming the resistance heating element 12 and the conductor circuit 18 is printed to form the conductor paste layers 120 and 180. Then, the conductor paste filling layers 130 and 130 'for the through holes 13 and 13' and the conductor paste layer 160 for the via holes 16 are formed in the through holes. The conductive paste contains metal particles or conductive ceramic particles.

The average particle size of the above-mentioned metal particles such as tungsten particles or molybdenum particles is preferably 0.1 to 5 μm. This is because it is difficult to print the conductor paste when the average particle size is less than 0.1 μm or exceeds 5 μm.

Examples of such a conductor paste include, for example, 85 to 87 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. And a composition (paste) in which 1.5 to 10 parts by weight of at least one solvent selected from α-terpineol and glycol is mixed.

(3) Laminating step of green sheet Green sheet 11 on which no conductor paste is printed is provided above and below the green sheet on which conductor paste layer 120 is printed.
A plurality of 0s are stacked (FIG. 11A). At this time, the number of green sheets 110 stacked on the upper side of the green sheet on which the conductor paste layer 120 is printed is made larger than the number of green sheets 110 stacked on the lower side, and the formation position of the resistance heating element to be manufactured is on the bottom side. Eccentric in the direction of. Specifically, the number of stacked green sheets 110 on the upper side is 20 to 50.
The number of stacked green sheets 110 on the lower side is 5 to 20.
Sheets are preferred.

(4) Firing step of the green sheet laminate The green sheet 1 is heated to heat the green sheet 1.
10 and the conductor paste inside are sintered to form through holes 13, 13 'and via holes 16 (FIG. 11).
(B)). Here, the firing of the green sheet laminate is performed in a mixed atmosphere of CO and N ₂ . The heating temperature at this time is preferably 1000 to 2000 ° C. The heating is performed in an inert gas atmosphere. As an inert gas,
For example, argon, nitrogen, etc. can be used.
In addition, at the stage where this green sheet firing process is completed,
The carbon concentration in the sintered body is uniform throughout.

Next, in the obtained sintered body, through holes for lifter pins for inserting the lifter pins 8 for supporting the silicon wafer 9, bottomed holes for embedding a temperature measuring element such as a thermocouple, etc. are formed. Form.

The step of forming the through hole and the bottomed hole may be performed on the green sheet laminate, but is preferably performed on the sintered body. This is because there is a risk of deformation during the sintering process. Next, through holes 13 and 1 formed in the ceramic substrate 11.
Screw holes 19 were formed on the bottom surface of 3'by drilling.

At the stage where this green sheet firing process is completed, the carbon concentration in the ceramic substrate 11 is generally uniform.

(5) Non-uniform carbon treatment step Next, for the purpose of lowering the concentration of carbon contained in the ceramic substrate 11 in the vicinity of the surface of the ceramic substrate 11 as compared with the inside of the ceramic substrate 11, the ceramic substrate 11 11 is subjected to carbon non-uniformity treatment. Specifically, the ceramic substrate 11 obtained in the step (4) is heated to 1800 to 2000 ° C. under normal pressure and N ₂ gas atmosphere. Note that heating at normal pressure makes it easier for carbon in the ceramic substrate to be oxidized, and the carbon to escape as gas in a larger proportion, as compared with the case of heating under pressure.

In the carbon non-uniformizing step, it is desirable to add a trace amount of oxygen in addition to N ₂ gas. This is because the oxidation of carbon near the surface of the ceramic substrate 11 is further promoted, and the carbon concentration near the surface of the ceramic substrate can be further reduced.

(6) Manufacture of Ceramic Body Ceramic powder such as aluminum nitride is put into a cylindrical mold and molded, and if necessary, cut. This is sintered at a heating temperature of 1000 to 2000 ° C. under normal pressure to manufacture a cylindrical ceramic body 17 made of ceramic. The sintering is performed in an inert gas atmosphere. As an inert gas,
For example, argon, nitrogen or the like can be used. Here, it is desirable that the ceramic powder contains yttria or the like as a sintering aid. The size of the ceramic body 17 is adjusted so that the through holes 13 and 13 'formed inside the ceramic substrate fit inside the through holes 13 and 13'. Then, the end surface of the ceramic body 17 is polished and flattened.

(7) Coating process of bonding aids Ceramic substrate 11 and / or manufactured in the process of (6)
Alternatively, a solution containing a sintering aid is applied to the joint surface of the ceramic body 17. As the sintering aid, water-soluble yttrium chloride, yttrium sulfate, yttrium acetate, yttrium nitrate, ytterbium chloride, ytterbium sulfate,
Ytterbium acetate, ytterbium nitrate, etc. can be used. The concentration of the solution is 0.2-0.3 m
ol / l is desirable. As a solvent for the solution, water, alcohol, etc. are desirable. This is because the above-mentioned yttrium chloride and the like dissolve in these solvents.

(8) Bonding Step of Ceramic Substrate and Ceramic Body Then, after the ceramic body 17 is brought into contact with the vicinity of the central portion of the bottom surface 11b of the ceramic substrate 11, the ceramic body 17 and the ceramic body 11 are heated by heating them. Body 17
Join with. At this time, the through holes 13 and 13 ′ in the ceramic substrate 11 are formed inside the inner diameter of the ceramic body 17.
The ceramic body 17 so that
It is bonded to the bottom surface 11b of the (FIG. 11 (c)).

When the ceramic substrate 11 and the ceramic body 17 are bonded together, it is desirable to heat them at 1000 to 2000 ° C. In such a joining method, since the relative concentration of the ceramic particles in the joining surfaces of the ceramic body 17 and the ceramic substrate 11 becomes high, the grain growth of the ceramic particles occurs well at the interface between the two, so that the ceramic particles are Substrate 11 and ceramic body 17
And can be firmly joined.

Furthermore, when the ceramic substrate 11 and the ceramic body 17 are joined, 0.5-10 kPa (5-1
It is desirable to press the ceramic body 17 against the ceramic substrate 11 with a pressure of 00 g / cm ² ) and heat the ceramic substrate 17 to bond them. By bonding in such a pressed state, it is possible to reduce the gap generated between the ceramic substrate 11 and the ceramic body 17, so that they can be bonded more firmly.

(9) Attachment of Terminals, etc. External terminals 23 having a threaded portion at the tip are screwed into the screw holes 19 formed on the bottoms of the through holes 13 and 13 'of the ceramic substrate 11 to connect the external terminals 23 to the through hole 1.
3 and 13 '(FIG. 11 (d)). The external terminals 23 and the through holes 13 and 13 'are connected to the through holes 13 and 13' by using a method such as soldering or brazing the external terminal 23 having a T-shaped cross section. Good.

Next, the external terminal 23 is connected to the conductive wire 230 connected to the power source through the socket 31. Further, the temperature measuring element 21 is inserted into the formed bottomed hole 14 and sealed with a heat resistant resin or the like, whereby the resistance heating element 1
It is possible to manufacture a hot plate 10 with a ceramic substrate 11 having two.

In this hot plate, a semiconductor wafer such as a silicon wafer is placed on a ceramic substrate, or the silicon wafer or the like is held by lifter pins or support pins and then heated or cooled. While performing, operations such as washing can be performed.

When manufacturing the hot plate, an electrostatic chuck can be manufactured by providing an electrostatic electrode inside the ceramic substrate. However, in this case,
It is necessary to form a through hole for connecting the electrostatic electrode and the external terminal, but it is not necessary to form a through hole for inserting the support pin.

When the electrodes are provided inside the ceramic substrate, a conductor paste layer serving as an electrostatic electrode may be formed on the surface of the green sheet as in the case of forming the resistance heating element.

Further, by supporting the hot plate 10 with a supporting container as shown in FIG. 3, a hot plate unit can be obtained.

Next, a method for manufacturing a hot plate having a resistance heating element formed on the bottom surface of a ceramic substrate will be described. 12A to 12D are cross-sectional views schematically showing a part of the method for manufacturing the hot plate in which the resistance heating element is formed on the bottom surface of the ceramic substrate.

(1) Step of Manufacturing Ceramic Substrate Yttria (Y) is added to the above-mentioned ceramic powder of a nitride such as aluminum nitride or silicon carbide, if necessary.
₂ O ₃ ) or B ₄ C or the like, a sintering aid, a compound containing Na, Ca, a binder, etc. are mixed to prepare a slurry, and the slurry is granulated by a method such as spray drying. It is put in a mold and pressed to form a plate or the like to produce a green body (green).

Note that crystalline or amorphous carbon is added to the green body. Examples of the method of adding crystalline carbon include a method of directly adding graphite powder, and examples of the method of adding amorphous carbon include a method of thermally decomposing an acrylic resin or the like.

Next, this green body is heated and fired to be sintered to produce a ceramic plate-like body. After that, the ceramic substrate 51 is manufactured by processing it into a predetermined shape, but it may have a shape that can be used as it is after firing. By heating and firing while applying pressure, it becomes possible to manufacture a ceramic substrate 51 having no pores. The heating and firing may be carried out at a sintering temperature or higher, but in the case of nitride ceramics and carbide ceramics, it is 100
It is 0-2500 degreeC. In oxide ceramics,
It is 1500 ° C to 2000 ° C.

Further, a drilling process is carried out to form a lifter pin through hole 55 for inserting the lifter pin 8 for supporting the silicon wafer 9 and a bottomed hole 54 for embedding a temperature measuring element such as a thermocouple. To form a part to be.
(See FIG. 12 (a)).

At the stage where the green sheet firing process is completed, the carbon concentration in the ceramic substrate 51 is generally uniform.

(2) Non-uniform carbon treatment step Next, for the purpose of reducing the concentration of carbon contained in the ceramic substrate 51 in the vicinity of the surface of the ceramic substrate 51 as compared with the inside of the ceramic substrate 51, the ceramic substrate 51 51 is subjected to carbon non-uniformity treatment. Specifically, the ceramic substrate 51 obtained in the step (1) is heated to 1800 to 2000 ° C. under normal pressure and N ₂ gas atmosphere. Note that heating at normal pressure makes it easier for carbon in the ceramic substrate to be oxidized, and the carbon to escape as gas in a larger proportion, as compared with the case of heating under pressure.

In the carbon nonuniformizing step, it is desirable to add a trace amount of oxygen in addition to the N ₂ gas. This is because the oxidation of carbon near the surface of the ceramic substrate 51 is further promoted, and the carbon concentration near the surface of the ceramic substrate can be further reduced.

(3) Process of Printing Conductor Paste on Ceramic Substrate Generally, the conductor paste is a highly viscous fluid containing metal particles, resin and solvent. The conductor paste layer is formed by printing the conductor paste on the portion where the resistance heating element 52 is to be provided by screen printing or the like. The conductor paste layer is preferably formed such that the resistance heating element 52 after firing has a rectangular cross section. Further, it is desirable to use a refractory metal such as tungsten or molybdenum for the conductor paste.

(4) Firing of Conductor Paste The conductor paste layer printed on the bottom surface of the ceramic substrate 51 is heated and fired to remove the resin and the solvent, and the metal particles are sintered and baked on the bottom surface of the ceramic substrate 51.
The resistance heating element 52 is formed. The temperature for heating and firing is 500
The temperature is preferably 1000 ° C. When the above-mentioned oxide is added to the conductor paste, the metal particles, the ceramic substrate and the oxide are sintered and integrated, so that the adhesion between the resistance heating element 52 and the ceramic substrate 51 is improved.

(5) Formation of Metal Cover Layer Next, a metal cover layer 520 is formed on the surface of the resistance heating element 52. The metal coating layer 520 can be formed by electrolytic plating, electroless plating, sputtering, etc.
Considering mass productivity, electroless plating is most suitable (Fig. 1
2 (b)).

(6) Manufacture of Ceramic Body Ceramic powder such as aluminum nitride is put into a cylindrical mold and molded, and if necessary, cut. This is sintered at a heating temperature of 1000 to 2000 ° C. under normal pressure to manufacture a ceramic cylindrical ceramic body 57. The sintering is performed in an inert gas atmosphere. As an inert gas,
For example, argon, nitrogen, etc. can be used.
Further, a concave portion corresponding to the shape of the resistance heating element 52 is formed on the joint surface 57a of the ceramic body 57. This allows
Even when the resistance heating element 52 crosses the joint surface between the ceramic body 57 and the ceramic substrate 51, the ceramic substrate 51 and the ceramic body 57 can be closely adhered to each other without a gap, and these can be firmly joined. it can. Here, it is desirable that the ceramic powder contains yttria or the like as a sintering aid.

(7) Application of the bonding aid The ceramic substrate 51 and / or manufactured in the step (6)
Alternatively, a solution containing a sintering aid is applied to the joint surface of the ceramic body 57. As the sintering aid, water-soluble yttrium chloride, yttrium sulfate, yttrium acetate, yttrium nitrate, ytterbium chloride, ytterbium sulfate,
Ytterbium acetate, ytterbium nitrate, etc. can be used. The concentration of the solution is 0.2-0.3 m
ol / l is desirable. As a solvent for the solution, water, alcohol, etc. are desirable. This is because the above-mentioned yttrium chloride and the like dissolve in these solvents.

(8) Joining Process of Ceramic Substrate and Ceramic Body Next, after the ceramic body 57 is brought into contact with the bottom surface 51b of the ceramic substrate 51, these are heated to
The ceramic substrate 51 and the ceramic body 57 are joined.
At this time, the ceramic body 57 is bonded to the bottom surface 51b of the ceramic substrate 51 so that the concave portion formed on the bonding surface of the ceramic body 57 and the resistance heating element 52 correspond to each other. And
The gap formed between the ceramic body 57 and the resistance heating element 52 is sealed with silica sol, polyimide or the like (see FIG. 12C).

When the ceramic substrate 51 and the ceramic body 57 are joined together, it is desirable to heat them at 1000 to 1600 ° C. In such a joining method, since the relative concentration of the ceramic particles in the joining surfaces of the ceramic body 57 and the ceramic substrate 51 becomes high, the grain growth of the ceramic particles occurs well at the interface between the two, so that the ceramic particles are not mixed with each other. Substrate 51 and ceramic body 57
And can be firmly joined.

(9) Attaching terminals and the like External terminals 63 for connecting to a power source are attached to the ends of the pattern of the resistance heating element 52 by soldering. Also, the bottomed hole 54
Fix the thermocouple (not shown) with silver solder, gold solder, etc.
Hot plate 50 sealed with heat resistant resin such as polyimide
Is finished (see FIG. 12D).

In the case of the hot plate 50 as well, as in the case of the hot plate 10, it can be made into a hot plate unit by supporting it with a supporting container as shown in FIG.

The present invention will be described in more detail below.

【Example】

(Example 1) Production of hot plate (see FIGS. 1, 2 and 11) (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), yttrium oxide (Y ₂ O)
₃ : 4 parts by weight of yttria, average particle size 0.4 μm, acrylic resin binder (KC-600 manufactured by Kyoeisha)
Acid value 10 KOHmg / g) 11.5 parts by weight, dispersant 0.
A paste obtained by mixing 5 parts by weight and 53 parts by weight of an alcohol composed of 1-butanol and ethanol was molded by a doctor blade method to have a thickness of 0.47 m.
A green sheet 110 having a diameter of m and a diameter of 330 mm was produced.

(2) Next, after drying this green sheet 110 at 80 ° C. for 5 hours, it becomes a through hole 15 for inserting a lifter pin for carrying a silicon wafer as shown in FIG. Part, part 1 to be a via hole
60, and the portions 130 and 13 to be through holes
0'was formed by punching.

(3) A conductor obtained by mixing 100 parts by weight of tungsten carbide particles having an average particle size of 1 μm, 3.0 parts by weight of an acrylic binder, 3.5 parts by weight of an α-terpineol solvent and 0.3 part by weight of a dispersant. Paste A was prepared.

Tungsten particles 100 having an average particle size of 3 μm
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 were mixed to prepare a conductor paste B.

This conductor paste A was screen-printed on a green sheet having a portion 160 to be a via hole, to form a conductor paste layer 120 for a resistance heating element. The printed pattern was a combination of concentric circles as shown in FIG. 2 and circular arcs divided in the circumferential direction, and the conductor paste layer 120 had a width of 10 mm and a thickness of 12 μm.

Subsequently, the conductor paste A is printed by screen printing on the green sheet on which the portion 130 'to be the through hole is formed, and the conductor paste layer 180 for the conductor circuit is formed.
Was formed. The print shape was a band.

Further, the conductive paste B is added to the portion 160 to be a via hole and the portion 130 to be a through hole.
Filled 130 '.

The conductor paste layer 120 which has been subjected to the above processing
37 sheets of the green sheet on which the conductor paste is not printed are stacked on the green sheet on which the conductor paste is printed, the green sheet on which the conductor paste layer 180 is printed is stacked under the green sheet, and the conductor paste is printed on the bottom of the green sheet. Twelve green sheets that had not been formed were stacked and laminated at 130 ° C. and a pressure of 8 MPa.

(4) Next, the obtained laminated body was degreased in nitrogen gas at 600 ° C. for 5 hours, at 1890 ° C. and a pressure of 15M.
It was hot pressed at Pa for 10 hours to obtain an aluminum nitride plate-shaped body having a thickness of 3 mm. This is cut into a disk shape of 230 mm, and the resistance heating element 1 having a thickness of 6 μm and a width of 10 mm is internally formed.
2. A ceramic substrate 11 having a conductor circuit 18 having a thickness of 20 μm and a width of 10 mm, a via hole 16 and through holes 13 and 13 ′.

(5) Next, the ceramic substrate 11 obtained in (4) was polished with a diamond grindstone and then heated in N ₂ gas at 1800 ° C. and normal pressure for 1 hour.

(6) A mask was placed, and a bottomed hole 14 for a thermocouple was provided on the surface by blasting with glass beads. Then, after forming a bottomed hole on the bottom surface of the through holes 13 and 13 'formed in the ceramic substrate 11 by drilling, a screw groove is provided in this bottomed hole to form the screw hole 19
Was formed.

(7) Aluminum nitride powder (manufactured by Tokuyama Corp., average particle size 1.1 μm) 100 parts by weight, Y ₂ O ₃ (average particle size 0.4 μm) 4 parts by weight, acrylic resin binder 11.5 parts by weight , 0.5 parts by weight of a dispersant and 53 parts by weight of an alcohol consisting of 1-butanol and ethanol were mixed to prepare granules by a spray drying method, and the granules were put in a cylindrical mold and Pressure, 1890
Sintered at ℃, length 200mm, outer diameter 45mm, inner diameter 3
A 5 mm ceramic body 17 was produced.

(8) Yttrium nitrate (2.61 × 10 6) is formed on the joint surface between the ceramic substrate 11 and the ceramic body 17.
^-1 mol / L) After applying the aqueous solution, the end surface of the ceramic body 17 is brought into contact with the bottom surface 11b of the ceramic substrate 11 at a position where the bag hole 19 is set inside the inner diameter and heated to 1890 ° C. The ceramic substrate 1
1 and the ceramic body 17 were joined.

(9) Next, after screwing the external terminal 23 having the thread groove formed at the tip into the screw hole 19 formed in the through holes 13 and 13 ', the socket 3 is inserted into the external terminal 23.
The conductive wire 230 was connected through 1.

(10) Then, a thermocouple for temperature control is inserted into the hole 14 having a bottom, silica sol is filled, and 190 ° C.
After being hardened and gelled for 2 hours, the cylindrical ceramic body is bonded to the bottom surface of the ceramic substrate having the resistance heating element, the conductor circuit, the via hole and the through hole provided therein, and the ceramic substrate is hot. A ceramic bonded body that functions as a plate was manufactured.

Example 2 Production of Hot Plate (See FIGS. 5, 6 and 12) (1) Aluminum Nitride Powder (Average Particle Size: 0.6 μm)
100 parts by weight, yttria (average particle size: 0.4 μm) 4
Parts by weight, acrylic binder (Kyoeisha product name SA-5
A composition comprising 12 parts by weight of 45 acid value 0.5 KOHmg / g) and alcohol was spray-dried to prepare a granular powder.

(2) Next, the granular powder was put into a mold and molded into a flat plate to obtain a green molded body (green).

(3) Next, this green body was treated at 1800 ° C.
It was hot pressed at a pressure of 20 MPa to obtain an aluminum nitride plate-shaped body having a thickness of 3 mm. Next, a disc body having a diameter of 230 mm was cut out from this plate body to obtain a ceramic plate body (ceramic substrate 51).

(4) Then, the ceramic substrate 51 obtained in (3) was heated in N ₂ gas at 1800 ° C. and normal pressure for 5 hours.

(5) Next, the ceramic substrate 51 was drilled to form a lifter pin through hole 55 into which the lifter pin 8 of the silicon wafer is inserted, and a bottomed hole 54 for embedding a thermocouple. (See FIG. 12 (a))

(6) Ceramic substrate 5 obtained in (5) above
1, a conductor paste layer was formed by screen printing.
The print pattern was an arc pattern which was repeatedly formed by drawing a part of a concentric circle as shown in FIG. As the conductor paste, 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, an acrylic binder 1.
A composition having 9 parts by weight, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant was used.

(7) Further, after forming the conductor paste layer of the heating element pattern, the ceramic substrate 51 is heated and fired at 780 ° C. to sinter the tungsten particles in the conductor paste and bake it on the ceramic substrate 51. The resistance heating element 52 was formed. The resistance heating element 52 has a thickness of 5
μm, the width was 2.4 mm, and the sheet resistivity was 7.7 mΩ / □.

(8) Nickel sulfate 80 g / l, sodium hypophosphite 24 g / l, sodium acetate 12 g / l,
The ceramic substrate 51 prepared in (7) above was immersed in an electroless nickel plating bath consisting of an aqueous solution having a concentration of 8 g / l boric acid and 6 g / l ammonium chloride, and a thickness of 1 μm was formed on the surface of the resistance heating element 52 of silver-lead. Metal coating layer (nickel layer)
520 was deposited (see FIG. 12 (b)).

(9) Aluminum nitride powder (manufactured by Tokuyama Corp., average particle size 1.1 μm) 100 parts by weight, Y ₂ O ₃ (average particle size 0.4 μm) 4 parts by weight, acrylic resin binder 11.5 parts by weight , 0.5 parts by weight of a dispersant and 53 parts by weight of an alcohol consisting of 1-butanol and ethanol were mixed to prepare granules by a spray drying method, and the granules were put in a cylindrical mold and Pressure, 1890
Sintered at ℃, length 200mm, outer diameter 15mm, inner diameter 5
Eight mm mm ceramic bodies 57 were manufactured. Then, the joint surface 57a of the ceramic body 57 is blasted,
A recess corresponding to the shape of the resistance heating element 52 was formed.

(10) Yttrium nitrate (2.61 × 1) is formed on the joint surface of the ceramic substrate 51 and the ceramic body 57.
(0 ⁻¹ mol / L) aqueous solution is applied, and then the end surface of the ceramic body 57 is brought into contact with the bottom surface 51 b of the ceramic substrate 51 at a position where the end portion of the resistance heating element 52 fits inside the inner diameter thereof. Then, the ceramic substrate 51 and the ceramic body 57 were joined by heating to 1890 ° C. (see FIG. 12C).

(11) Next, a silver-lead solder paste (manufactured by Tanaka Kikinzoku Co., Ltd.) is printed by screen printing on the portion where the external terminal 63 for securing the connection with the power supply is attached, and the solder layer (not shown). Form). Next, the external terminal 63 made of Kovar was placed on the solder layer and heated at 420 ° C. for reflow, and the external terminal 63 was attached to the surface of the resistance heating element 52. (See FIG. 12 (d))

(12) Then, a gap between the ceramic body 57 and the resistance heating element 52 and a thermocouple (not shown) for temperature control are sealed with polyimide, and the hot plate 5 is used.
I got 0.

Example 3 Manufacturing of Electrostatic Chuck (FIG. 7)
(1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), 4 parts by weight of yttrium (average particle size 0.4 μm), acrylic resin binder 12
(Kyoeisha brand name KC-600 acid value 16KOHmg
/ G) part by weight, a dispersant 0.5 part by weight, and a composition obtained by mixing 53 parts by weight of an alcohol consisting of 1-butanol and ethanol, and by molding using a doctor blade method, a thickness of 0.47 mm is obtained. I got a green sheet.

(2) Next, this green sheet is heated to 80 ° C.
After drying for 5 hours, the unprocessed green sheet is punched and the green sheet is provided with through holes for via holes for connecting the resistance heating element and the conductor circuit, and the conductor circuit and the outside. A green sheet provided with a via hole through hole for connecting a terminal and a green sheet provided with a through hole through hole for connecting an electrostatic electrode and an external terminal were produced.

(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. Further, 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 parts by weight of a dispersant.

(4) Conductor paste A was printed by a screen printing method on the surface of the green sheet provided with through holes for via holes to print a conductor paste layer to be a resistance heating element. Further, the conductive paste A is printed by a screen printing method on the surface of the green sheet provided with through holes for through holes for connecting the conductor circuit and the external terminals to print a conductor paste layer to be a conductor circuit. . Further, a conductor paste layer having an electrostatic electrode pattern having the shape shown in FIG. 8 was formed on the green sheet which was not processed.

Further, the conductor paste B was filled in the through holes for via holes for connecting the resistance heating element and the conductor circuit and the through holes for through holes for connecting the external terminals.

Next, the green sheets that had been subjected to the above treatment were laminated. First, on the upper side (heating surface side) of the green sheet on which the conductor paste layer serving as the resistance heating element is printed, 34 green sheets in which only the portions to be the through holes 73 are formed are stacked, and immediately below (the bottom surface). Side) is laminated with a green sheet on which a conductor paste layer to be a conductor circuit is printed, and further, through holes 73, 73 are provided under the green sheet.
Twelve green sheets each having a portion corresponding to 0,730 'were formed. A green sheet on which a conductor paste layer composed of an electrostatic electrode pattern is printed is laminated on the top of the thus laminated green sheet, and two unprocessed green sheets are further laminated thereon. A laminated body was formed by pressure bonding at 130 ° C. and a pressure of 8 MPa.

(5) Next, the obtained laminate was degreased in an inert gas at 600 ° C. for 5 hours, and then hot pressed for 3 hours at 1890 ° C. and a pressure of 15 MPa to give a thickness of 3 m.
A ceramic substrate 71 of m was obtained. 230 mm diameter
It is cut out into a disc shape and has a thickness of 5 μm and a width of 2.
4 mm resistance heating element 720, thickness 20 μm, width 10
A ceramic substrate 71 having a conductor circuit 780 mm of mm, a chuck positive electrode electrostatic layer 72a and a chuck negative electrode electrostatic layer 72b having a thickness of 6 μm was obtained.

(6) Next, the ceramic substrate 71 obtained in (5) was heated in N ₂ gas at 1800 ° C. and normal pressure for 3 hours.

(7) Next, after polishing the ceramic substrate 71 with a diamond grindstone, a mask is placed and a bottomed hole 700 for a thermocouple is provided on the surface by blasting with glass beads. A bag hole 790 is formed by scooping out the portion of the bottom surface 71b where the through holes 73 and 73 'are formed.

(8) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), 4 parts by weight of yttria (average particle size 0.4 μm), 11.5 parts by weight of acrylic resin binder, dispersant Using a composition obtained by mixing 0.5 parts by weight and 53 parts by weight of an alcohol composed of 1-butanol and ethanol, granules were produced by a spray drying method, and the granules were put into a pipe-shaped mold and subjected to normal pressure, 1
Sintered at 890 ° C, length 200 mm, outer diameter 45 mm,
A ceramic body 77 having an inner diameter of 35 mm was manufactured.

(9) Ytterbium nitrate (2.61 × 1) is formed on the joint surface of the ceramic substrate 71 and the ceramic body 77.
(0 ⁻¹ mol / L) aqueous solution is applied, and then the end face of the ceramic body 77 is brought into contact with the bottom surface 71b of the ceramic substrate 71 at a position where the bag hole 79 fits inside its inner diameter, and the temperature is raised to 1890 ° C. By heating, the ceramic substrate 71 and the ceramic body 77 were joined.

(10) Next, in the bag hole 790 inside the ceramic body 77, silver solder (Ag: 40% by weight, Cu: 30)
%, Zn: 28% by weight, Ni: 1.8% by weight, balance: other elements, reflow temperature: 800 ° C.), and the external terminal 760 was attached. And the external terminal 7
The conductive wire 731 was connected to 60 through the socket 750.

(11) Then, a thermocouple for temperature control is inserted into the hole 700 having a bottom, and silica sol is filled, and 190
By hardening and gelling at ℃ for 2 hours, the cylindrical ceramic body is bonded to the bottom surface of the ceramic substrate in which the electrostatic electrode, the resistance heating element, the conductor circuit, the via hole and the through hole are provided. A ceramic bonded body in which the ceramic substrate functions as an electrostatic chuck was manufactured.

Example 4 In the step (5) of Example 1,
A hot plate was produced in the same manner as in Example 1 except that the heating time was 30 minutes.

(Comparative Example 1) After manufacturing a ceramic substrate by carrying out the steps (1) to (4) of Example 1,
With respect to the obtained ceramic substrate, a hot plate was manufactured in the same manner as in Example 1 except that the carbon nonuniformizing step (5) was not performed.

Comparative Example 2 After manufacturing a ceramic substrate by carrying out the steps (1) to (3) of Example 2,
With respect to the obtained ceramic substrate, a hot plate was manufactured in the same manner as in Example 2 except that the carbon nonuniformizing step (4) was not performed.

(Comparative Example 3) After manufacturing a ceramic substrate by carrying out the steps (1) to (5) of Example 3,
An electrostatic chuck was manufactured in the same manner as in Example 3 except that the carbon nonuniformizing step (5) was not performed on the obtained ceramic substrate.

The following evaluation tests were performed on the ceramic joined bodies according to Examples 1 to 4 and Comparative Examples 1 to 3. The results are shown in Table 1 below.

(1) Measurement of Carbon Concentration When sample pieces collected from the vicinity of the surface of the ceramic substrate and inside were crushed and heated at 500 to 800 ° C.,
It was carried out by collecting the generated CO _x gas.

(2) Measurement of Lightness Based on the JIS Z 8721, the lightness of the ceramic bonded body was measured from the Munsell color chart.

(3) Measurement of Wafer Temperature A wafer was placed on a ceramic bonded body so as to be separated from the surface of the ceramic substrate by 200 μm via support pins, and then heated in a vacuum at 400 ° C. The temperature of the wafer was measured with a thermocouple.

(4) Measurement of Breaking Strength A bending strength test was conducted to measure the breaking strength of the joint surface between the ceramic body and the ceramic substrate.

(5) Heat Cycle Test A heat cycle test, in which the process of holding at 25 ° C. and then heating to 450 ° C. is repeated 500 times, was performed to confirm the occurrence of cracks at the joint between the ceramic body and the ceramic substrate. .

(6) Presence of Corrosion of Wiring etc. Corrosion of wiring etc. of the ceramic bonded body after the ceramic bonded bodies according to the examples and comparative examples were attached to a support container and heated up to 300 ° C. in a CF ₄ gas atmosphere. The state was visually observed. In addition, N ₂ gas was introduced as an inert gas into the inside of the ceramic body.

[0203]

[Table 1]

As is clear from the results shown in Table 1, the ceramic bonded bodies according to Examples 1 to 4 have sufficiently large bonding strengths in both the fracture strength test and the heat cycle test. Further, the wirings and the like arranged inside the ceramic body of these ceramic bonded bodies were not corroded by CF ₄ gas. This is comparable to the conventional one. Further, the brightness is as low as 6 or less, and the hiding property is excellent. Further, radiant heat can be used. This is because in the ceramic heaters according to Examples 1 to 4, the concentration of carbon contained in the ceramic substrate near the surface of the ceramic substrate is lower than the concentration inside the ceramic substrate. The diffusion of the sintering aid is not hindered by the presence of carbon at the joint surface of the ceramic substrate, and the grain growth of the ceramic particles occurs well at the interface between the two, and the sintering aid acts as an aid. Therefore, it was considered that the above-mentioned ceramic substrate and the above-mentioned ceramic body can be firmly bonded to each other.

[0205]

As described above, in the ceramic joined body of the present invention, the concentration of carbon contained in the ceramic substrate near the surface of the ceramic substrate is lower than the concentration inside the ceramic substrate. Therefore, when a solution containing a sintering aid is applied to the joint surface of the ceramic body, and the ceramic body and the ceramic substrate are joined together by heating, the relative amounts of the ceramic particles on the joint surface of the ceramic body and the ceramic substrate are Due to the increase in the effective concentration, the grain growth of the ceramic particles occurs favorably at the interface between the two, so that the ceramic substrate and the ceramic body can be firmly bonded.

Since the method for manufacturing a ceramic joined body of the present invention is as described above, the carbon concentration inside the ceramic substrate is not significantly changed,
Since only the carbon concentration near the surface of the ceramic substrate can be reduced, it is possible to manufacture a ceramic joined body having excellent corrosion resistance and durability.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing a hot plate which is an example of a ceramic bonded body of the present invention.

FIG. 2 is a plan view of the hot plate shown in FIG.

FIG. 3 is a sectional view schematically showing a carbon distribution state in the hot plate shown in FIG.

FIG. 4 is a cross-sectional view schematically showing a case where a hot plate unit is formed by supporting the hot plate shown in FIG. 1 with a support container.

FIG. 5 is a plan view schematically showing a hot plate which is another example of the ceramic joined body of the present invention.

FIG. 6 is a plan view of the hot plate shown in FIG.

FIG. 7 is a plan view schematically showing an electrostatic chuck which is another example of the ceramic bonded body of the present invention.

FIG. 8 is a horizontal cross-sectional view schematically showing an example of an electrostatic electrode embedded in a ceramic substrate.

FIG. 9 is a horizontal sectional view schematically showing another example of the electrostatic electrode embedded in the ceramic substrate.

FIG. 10 is a horizontal sectional view schematically showing still another example of the electrostatic electrode embedded in the ceramic substrate.

11A to 11D are cross-sectional views schematically showing an example of a method for manufacturing a hot plate which is an example of the ceramic joined body of the present invention.

12A to 12D are cross-sectional views schematically showing an example of a method for manufacturing a hot plate which is another example of the ceramic joined body of the present invention.

[Explanation of symbols]

8 lifter pins 9 Silicon wafer 10, 50 hot plate 11, 51, 71 Ceramic substrate 12, 52, 720 Resistance heating element 13, 13'73, 73 'through hole 14, 54 Bottom hole 15, 55, 75 through holes 16,76 via holes 17, 57, 77 Ceramic body 18, 78 Conductor circuit 19 screw holes 20 Support container 520 metal coating layer 70 Electrostatic chuck 79 bag holes

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 3/74 H05B 3/20 393 // H05B 3/20 393 H01L 21/302 101G F term (reference) 3K034 AA02 AA15 AA21 BA06 BA14 BC04 BC17 DA04 JA01 3K092 PP20 QA05 QB02 QB31 QB43 QB68 QB75 RF03 RF11 RF19 RF27 UA05 VV09 4G026 BA16 BB16 BF01 BF41 BG04 EM05BB29 BB09 BB09 BB09 BB09 BB09 B22

Claims (4)

[Claims] 1. A ceramic bonded body in which a ceramic body is bonded to a bottom surface of a ceramic substrate having a conductor provided on the surface or inside thereof, the ceramic substrate containing carbon, and the surface of the ceramic substrate. A ceramic joined body, wherein the carbon concentration in the vicinity is lower than the carbon concentration inside the ceramic substrate. 2. The ceramic bonded body according to claim 1, wherein the conductor is a resistance heating element and functions as a hot plate. 3. The ceramic joined body according to claim 1, wherein the conductor is an electrostatic electrode and functions as an electrostatic chuck. 4. A ceramic substrate containing ceramic powder and carbon or carbon raw material is fired to produce a ceramic substrate containing carbon in a substantially uniform concentration, and the obtained ceramic substrate is under normal pressure at 1800 to 200.
After performing the carbon non-uniformization treatment at 0 ° C. under N ₂ gas atmosphere, the ceramic body having the bonding surface coated with the solution containing the sintering aid is brought into contact with the bottom surface of the ceramic substrate and heated. A method for producing a ceramic joined body, comprising joining the ceramic substrate and the ceramic body.