JP2002190371A - Ceramic heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic heater, with which the heating surface temperature of a ceramic substrate can be uniformized, in which no short circuiting occurs between the circuit ends of adjacent resistance heating elements, the end and the middle part of the circuit, or other different components, and of which the connection reliability can be maintained over a long period of usage. SOLUTION: The resistance heating element is formed on the surface of the ceramic substrate, the resistance heating element comprising one or a plurality of circuits having an outer terminal on its end. Among the pairs of the different outer terminals, the outer terminal and the circuit, and the different circuits, at least one pair consists of the components adjacent to each other with an insulation material interposed in-between.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic heater used as an apparatus for manufacturing or inspecting a semiconductor, and a ceramic heater which can be used also as an electrostatic chuck, a chap-top plate for a wafer prober and the like.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor manufacturing / inspection apparatus including an etching apparatus and a chemical vapor deposition apparatus, a chuck for a heater or a wafer prober using a metal base material such as stainless steel or aluminum alloy. Top plates and the like have been used.

[0003] However, such a metal heater has the following problems.
There were the following problems. First, because it is made of metal,
The thickness of the heater plate must be as thick as about 15 mm. This is because, in a thin metal plate, warpage, distortion, and the like are generated due to thermal expansion caused by heating, and the silicon wafer placed on the metal plate is damaged or tilted. However, when the thickness of the heater plate is increased, there is a problem that the weight of the heater increases 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 semiconductor wafer is controlled by changing a voltage or an amount of current applied to the resistance heating element. Because of the thickness, the temperature of the heater plate does not quickly follow changes in the voltage or the amount of current, and there is a problem that it is difficult to control the temperature.

Therefore, in Japanese Patent Application Laid-Open No. H11-40330, a nitride ceramic or a carbide ceramic having high thermal conductivity and high strength is used as a substrate, and a plate-like body (ceramic substrate) made of these ceramics is used. On the surface,
A ceramic heater provided with a resistance heating element formed by sintering metal particles is disclosed.

In such a ceramic heater, since a ceramic substrate having high mechanical strength is used even at high temperatures, the thickness of the ceramic substrate can be reduced to reduce the heat capacity. As a result, the voltage and current can be reduced. The temperature of the ceramic substrate can quickly follow the change in the amount.

Usually, in this type of ceramic heater, a temperature measuring element is attached to the surface or inside of a ceramic substrate,
After attaching the ceramic substrate to a metal supporting container via a resin heat insulating ring or the like, a metal wire from a thermocouple or a conductive wire from a resistance heating element is passed through a plurality of through holes provided in a bottom plate. From the support container and connected to a control device or the like, and a voltage is applied to the resistance heating element based on the temperature measured by the temperature measuring element to control the temperature of the ceramic substrate.

[0008]

However, in such a ceramic heater, as described above, the external terminals connected to both ends of the resistance heating element are connected to the support container via the opening or the like of the support container. Since it is drawn out, heat radiation occurs from this part.

[0009] In a conventional resistance heating element, for example, as shown in FIG.
In many cases, when the ceramic substrate 41 is heated to a high temperature, the resistance heating element 42 has one circuit.
Two low-temperature portions (hereinafter, referred to as cooling spots) are generated.
In this case, the temperature of the heating surface (the side opposite to the surface on which the resistance heating element is formed) becomes non-uniform, so that there is a problem that an object to be heated such as a semiconductor wafer cannot be heated uniformly. Therefore,
In order to reduce the number of such cooling spots and to make the temperature of the heating surface uniform, when a plurality of ends of the resistance heating element are present close to each other, migration of metal or the like occurs between the ends. There is a problem that short circuits are likely to occur due to the migration and the like. Further, the same problem easily occurs between circuits of the resistance heating element.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to reduce the number of cooling spots generated on a ceramic substrate and the like. Since the surface temperature can be made more uniform, the object to be heated such as a silicon wafer can be heated evenly, and between the ends of the circuit of the adjacent resistance heating element or between the end of the circuit and the circuit. An object of the present invention is to provide a ceramic heater which does not cause a short circuit with an intermediate portion or the like and can maintain connection reliability even when used for a long time.

[0011]

According to the ceramic heater of the present invention, a resistance heating element comprising one or a plurality of circuits having external terminals at its ends is formed on the surface of a ceramic substrate. At least one set is provided between terminals and the circuits, and between the circuits, and an insulator is interposed between the external terminals provided close to each other, between the external terminals and the circuits, and between the circuits. It is characterized by having been done.

In the ceramic heater according to the present invention, since the external terminals and the external terminals and the circuit are provided close to each other, the end portions of the resistive heating element and the external terminals are provided in the conventional ceramic heater. And the number of cooling spots can be reduced or eliminated as compared with the case where the circuits are formed apart from each other, and the temperature of the heating surface is made more uniform due to the reduction of the cooling spots. can do. Further, if the resistance heating elements are formed apart from each other, the temperature of the heating surface is likely to be non-uniform, but in the present invention, since these are provided close to each other, the temperature of the heating surface is made more uniform. be able to.

Further, according to the present invention, since an insulator is interposed between the external terminals and the like provided close to each other, it is possible to prevent a short circuit due to connection between the external terminals and between circuits and the like. In addition, metal migration and the like can be prevented, and short circuits caused by the migration and the like can also be prevented.

An example of the insulator is a resin having an insulating property. As this resin, at least one resin selected from a polyimide resin and a silicone resin is used.
Those consisting of seeds are preferred. This is because such a heat-resistant resin material has sufficient durability even when the temperature of the ceramic substrate rises to a temperature of about 250 ° C.

The insulator may be an oxide ceramic. The insulator made of oxide ceramic is
This is because even if the temperature of the ceramic substrate is as high as about 450 ° C., it has sufficient durability.

The oxide ceramic is preferably made of oxide glass, metal oxide sol or metal alkoxide as a raw material. As the oxide glass, lead glass, borosilicate, quartz glass, soda glass, or the like can be used.

Preferably, the ceramic substrate is made of a nitride ceramic or a carbide ceramic. This is because the nitride ceramics and carbide ceramics are excellent in mechanical properties such as strength and also have high thermal conductivity.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the ceramic heater of the present invention, a resistance heating element comprising one or more circuits having external terminals at its ends is formed on the surface of a ceramic substrate. Between the circuits, at least one set among the circuits is provided close to each other, an insulator is interposed between the external terminals provided close to each other, between the external terminals and the circuit, and between the circuits. It is characterized by having.

The ceramic heater of the present invention is a ceramic heater in which a resistance heating element comprising one or a plurality of circuits is provided on the surface of the ceramic heater. When only the resistance heating element is provided on the ceramic substrate, For example,
A resin layer or the like containing a solvent is formed on a semiconductor wafer or the like, and then functions as a heater or the like used for heating for evaporating the solvent or the like.

On the other hand, when a resistance heating element is formed on the surface of the ceramic substrate and an electrostatic electrode is provided therein, the ceramic heater functions as an electrostatic chuck, and the resistance heating element is formed on the surface of the ceramic substrate. When a body is formed and a guard electrode and / or a ground electrode are provided therein, it functions as a wafer prober (ceramic substrate for wafer prober).

FIG. 1 is a sectional view schematically showing an example of a hot plate unit using the ceramic heater of the present invention, and FIG. 2 is a bottom view of the ceramic heater. FIG. 3A is a partially enlarged cross-sectional view schematically showing a part of the ceramic heater, and FIG.
It is a bottom view of the part shown to (a).

The hot plate unit 10 includes a disc-shaped ceramic substrate 11 having a resistance heating element 12 formed on the bottom surface, and a cylindrical support container 20 having a bottom. On the bottom surface 11 b of the ceramic substrate 11, a plurality of resistance heating elements 12 having a concentric circular shape in a plan view are formed, and a plurality of bottomed holes 14 are formed. To measure the temperature,
Is embedded using a resin or the like.

The support container 20 includes a heat insulating ring 21 having an L-shaped cross section and a heat shielding member 22 for supporting the heat insulating ring 21. The heat insulating ring 21 is made of a fluorine resin or the like containing inorganic fibers or the like, and is fixed to an annular member provided above the heat shielding member 22 using bolts 28. The bolt 28 is attached via a fixing bracket 27, and the fixing bracket 27 is attached to the heat insulating ring 21.
The ceramic substrate 11 is fixed to the heat insulating ring 21 by reaching the end of the ceramic substrate 11 fitted in the ceramic substrate 11 and pressing the ceramic substrate 11 and the like with the fixing bracket 27. In addition, the bottom part of the heat shielding member 22 may be detachably attached.

As shown in FIG. 2, a plurality of resistance heating elements 12 formed of concentric circuits are formed on the bottom surface 11b of the ceramic substrate 11.
Is a set of double concentric circles close to each other,
They are connected so as to form one line.

As shown in FIG. 3, the resistance heating element 12
In order to prevent the oxidation, a metal coating layer 120 is formed on the surface, and a T-shaped external terminal is connected to an end 12a of the resistance heating element 12 having the metal coating layer 120 via a solder layer 18. 13 is connected. This external terminal 13
, A socket 25 having a conductive wire 24 is attached. The conductive wire 24 is led out of the support container 20 via a seal member fitted into the through hole 22 a of the heat shield member 22.

As shown in FIGS. 2 and 3, both ends 12a of each circuit of the resistance heating element 12 are provided close to each other with the resistance heating element 12 of the same circuit interposed therebetween. An insulating layer 110 made of the insulator of the present invention is provided continuously from the center to the outer periphery so as to cover the resistance heating element 12 and both end portions 12a sandwiched therebetween.

In a portion near the center of the ceramic substrate 11, a through hole 15 for inserting a lifter pin for supporting the silicon wafer W or the like is provided.
5, a guide pipe 2 communicating with the through hole 15 is provided so that the lifter pin can be smoothly inserted.
9 are provided.

The lifter pins are capable of placing the silicon wafer W thereon and moving the silicon wafer W up and down. While receiving the silicon wafer W, the silicon wafer W may be placed on the heating surface 11a of the ceramic substrate 11 and heated, or the silicon wafer W may be supported and heated while being spaced from the heating surface 11a by 50 to 2000 μm. I can do it.

Further, another through-hole or recess is provided in the ceramic substrate 11, and a pin having a spire or a hemispherical tip is inserted into the through-hole or recess, and then the support pin is slightly protruded from the ceramic substrate 11. By fixing the silicon wafer W with the support pins and supporting the silicon wafer W with the support pins, the silicon wafer W may be heated while being separated from the heating surface 11a by 50 to 2000 μm.

The heat shielding member 22 is provided with a refrigerant introduction pipe 26. The refrigerant such as air is introduced into the refrigerant introduction pipe 26 through a pipe (not shown), so that the temperature of the ceramic substrate 11 is reduced. And the cooling rate can be controlled, and as a result, the temperature of the silicon wafer W can be easily controlled.

In the hot plate unit 10, the ceramic substrate 11 is provided with a heat insulating ring 21
However, in another embodiment, the ceramic substrate may be mounted on the upper portion of the support container and fixed by a fixing member such as a bolt.

In this hot plate unit 10, as shown in FIG. 1, both ends of almost all the circuits of the resistance heating elements 12 are provided close to each other, so that the number of cooling spots can be reduced by half. it can. Also, since the circuits are provided close to each other, the ceramic substrate 11
The temperature of the heating surface can be made more uniform.

Further, since the continuous insulating layer 110 is formed between both ends 12a of almost all the resistance heating elements 12, the end 12a and the resistance heating elements 12 sandwiched therebetween are directly or indirectly connected to each other. A short circuit can be prevented from being generated by being connected via another conductor or the like, and a migration or the like of a metal can be prevented. Also, a short circuit due to the migration or the like can be prevented.

FIG. 4A is a partially enlarged sectional view schematically showing another example of the end of the resistance heating element circuit provided with an insulator, and FIG. 4B is a bottom view thereof. Insulator 110,
As shown in FIG. 3, 130 may be provided so as to cover the entire end portion 12a, between the end portions, and the periphery thereof, or as shown in FIG. 4, between the end portions and between the end portions. It may be provided so as to cover a part.

The distance between the external terminals, the distance between the external terminals and the circuits, and the circuits are preferably 0.1 to 20 mm. If the thickness is less than 0.1 mm, it is difficult to insulate. On the other hand, if it exceeds 20 mm, there is no need for insulation as in the present invention.

Further, as shown in FIG. 3, when a plurality of ends of the circuit of the resistive heating element are close to each other, the ends of the plurality of circuits are continuously connected by one insulating layer 110. Alternatively, as shown in FIG. 4, one insulating layer 130 may be provided for each set of ends.

The insulator is made of a resin, and the resin is
Desirably, it is composed of at least one selected from a polyimide resin and a silicone resin. A polyimide resin is a polymer compound obtained by reacting a carboxylic acid derivative with a diamine, has heat resistance of 200 ° C. or higher, and can be used in a wide temperature range. In addition, the silicone resin has a methyl group or an ethyl group as an alkyl group in the side chain of the polysiloxane, and has excellent heat resistance and rubber elasticity, and has good adhesion to a resistance heating element and a ceramic substrate. And 150-250
By drying and solidifying at a relatively low temperature of about ° C, an insulating coating can be formed.

As a method of forming such an insulating coating made of a heat-resistant resin material, a paste obtained by dissolving the above-mentioned heat-resistant resin material in a solvent or the like is applied or sprayed on the surface of the ceramic substrate, and dried to dry. And a method of forming a functional coating. Such a heat-resistant resin material has sufficient durability even when the temperature of the ceramic substrate rises to about 250 ° C.

The insulator may be made of an oxide ceramic. Oxide ceramic itself has high electrical insulation, has high adhesion strength to the ceramic substrate and resistance heating element, and is chemically stable, so it has a stable interface with the ceramic substrate and stability with the resistance heating element. Interface can be formed.

As a specific example, for example, ZnO
PbO-SiO ₂ mainly composed of _{ZnO-B 2 O 3 -SiO 2} , PbO mainly composed of, PbO-B ₂ O ₃ -S
iO _2, PbO-ZnO-B glass compositions such as ₂ O ₃ can be mentioned. These oxide ceramics may be formed of glass as described above, may be formed of a sintered body of crystalline particles, or may be formed of a composite thereof. When a glass material is used as the oxide ceramic, its glass transition point is 4
00 to 700 ° C. and a coefficient of thermal expansion of 4 to 9 ppm / ° C.
It is desirable that

As a method of forming such an insulating coating made of an oxide ceramic, a paste containing the above-mentioned oxide glass powder is applied to the surface of a ceramic substrate by screen printing or the like, and then dried and fired. And a method of forming a functional coating. In this case, it is necessary to form a layer made of a resin or the like that is relatively easily decomposed when heated so as not to form an insulating coating on the portion where the external terminal is formed.

The oxide ceramic may be made of a metal oxide sol or metal alkoxide as a raw material. These are easy to apply and contain a considerable amount of hydroxide immediately after application, but by drying and heating, water evaporates and the dehydration reaction proceeds, and ultimately most of them are dehydrated. This is because it becomes an oxide and firmly adheres to the ceramic substrate. These oxide ceramic insulators have a ceramic substrate temperature of 45
Even when it is as high as about 0 ° C., it has sufficient durability.

FIG. 5 is a bottom view schematically showing another example of the ceramic heater of the present invention, and FIG.
FIG. 2 is a partially enlarged sectional view schematically showing a part of the ceramic heater shown in FIG. 1, and FIG. 2B is a bottom view thereof.

In this ceramic heater 30, the resistance heating element 32 is formed on the bottom surface of the ceramic substrate 31 by a repetitive pattern of arcuate bent lines divided into several circuits in the circumferential direction. Extends concentrically from the center outward. The ends 32a of adjacent circuits are provided close to each other, and the insulating layer 140 is provided so as to cover these two ends 32a and between them.

In the conventional ceramic heater, the ends of the adjacent circuits are formed to be separated from each other to some extent, so that a cooling spot is generated at each end of each circuit. Since the end portions 32a of adjacent circuits are provided close to each other, the number of cooling spots can be halved, and the temperature of the heating surface can be made more uniform.

In this ceramic heater 30, as in the case of the ceramic heater 101 shown in FIG. 1, a through hole 35 for a lifter pin and a bottomed hole 34 are formed, and the other portions are also formed by the ceramic heater 101. It is configured similarly to.

FIG. 7A is a partially enlarged sectional view schematically showing another embodiment of the ceramic heater shown in FIG. 6, and FIG. 7B is a bottom view thereof. In the ceramic heater 30, the insulating layers 140 and 150 may be provided so as to cover the entire end 32a and the space between them, as shown in FIG. 6, or as shown in FIG. Part 3
It may be provided so as to cover a part of 2a and the space therebetween. As described above, when the ends of different circuits are provided close to each other, the distance between the external terminals is preferably 0.1 to 20 mm.

The pattern of the resistance heating element is shown in FIG.
In addition to the concentric circles shown in FIG. 5, as shown in FIG. 5, a repetition pattern of a bending line, a spiral shape, an eccentric circle, a pattern in which two or more of these patterns are repeated, and the like can be given.

When a resistive heating element having such a pattern is formed on the bottom surface of the ceramic substrate, it is preferable to use a conductive paste made of metal or conductive ceramic. That is, when the resistance heating element is formed on the surface of the ceramic substrate, the resistance heating element is usually formed by baking to produce the ceramic substrate, then forming a conductor paste layer on the surface, and firing. Form.

The conductive paste is not particularly limited, but preferably contains not only metal particles or conductive ceramics for ensuring conductivity, but also resin, solvent, 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 hard to oxidize and have a resistance value sufficient to generate heat.

As the conductive ceramic, for example,
Tungsten, molybdenum carbide and the like can be mentioned.
These may be used alone or in combination of two or more. The metal particles or conductive ceramic particles preferably have a particle size of 0.1 to 100 μm. If it is too fine, less than 0.1 μm, it is liable to be oxidized, while if it exceeds 100 μm, sintering becomes difficult and the resistance value becomes large.

The shape of the metal particles may be spherical,
It may be scaly. When these metal particles are used, they may be a mixture of the above-mentioned spheres and the above-mentioned flakes. When the metal particles are scaly or a mixture of spherical and scaly, the metal oxide between the metal particles is easily retained, and the adhesion between the resistance heating element and the ceramic substrate is ensured. And the resistance value can be increased.

As the resin used for the conductor paste,
For example, an epoxy resin, a phenol resin, and the like can be given. Examples of the solvent include isopropyl alcohol. Examples of the thickener include cellulose and the like.

When a conductor paste for a resistance heating element is formed on the surface of a ceramic substrate, a metal oxide is added to the conductor paste in addition to the metal particles, and the metal particles and the metal oxide are sintered. It is preferable that Thus, by sintering the metal oxide together with the metal particles, the ceramic substrate and the metal particles can be brought into close contact.

Although it is not clear why mixing metal oxide improves the adhesion to the ceramic substrate, the surface of metal particles or the surface of non-oxide ceramic substrate is slightly oxidized. Thus, an oxide film is formed, and it is considered that the oxide films are sintered and integrated through the metal oxide, and the metal particles and the ceramic adhere to each other. Further, when the ceramic constituting the ceramic substrate is an oxide, the surface is naturally made of an oxide, so that a conductor layer having excellent adhesion is formed.

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

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

The amount of the metal oxide added to the metal particles is preferably 0.1% by weight or more and less than 10% by weight. Further, the area resistivity when the resistance heating element is formed using the conductor paste having such a configuration is preferably 1 mΩ to 50 Ω / □.

If the sheet resistivity is less than 1 mΩ, the sheet resistivity becomes too small, so that it is impossible to secure a calorific value.
On the other hand, when the sheet resistivity exceeds 50Ω / □, the heat value becomes too large with respect to the applied voltage, and it is difficult to control the heat value in a ceramic substrate provided with a resistance heating element on the surface.

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

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

The ceramic substrate of the present invention is desirably used at 100 ° C. or higher, and more desirably at 200 ° C. or higher.

The material of the ceramic substrate is not particularly limited, and examples thereof include a nitride ceramic, a carbide ceramic, and an oxide ceramic.

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

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

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

Further, the ceramic material may contain a sintering aid. As the sintering aid, 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, Rb 2 O are preferred. Their content is 0.1 to 20% by weight.
Is preferred. Further, it may contain alumina.

The above ceramic substrate has a brightness of JIS Z
It is desirable that the value based on the rule of 8721 is N6 or less. This is because a material having such brightness is excellent in radiant heat and concealing property. Further, such a ceramic substrate can accurately measure the surface temperature by using a thermoviewer.

Here, the lightness N is defined as 0 for an ideal black lightness, 10 for an ideal white lightness, and the brightness of the color between these black lightness and white lightness. Each color is divided into ten so that the perception of the color is equal, and displayed by symbols N0 to N10. And the actual measurement is N0-N
The comparison is made with the color chart corresponding to No. 10. In this case, the first decimal place is 0 or 5.

A ceramic substrate having such characteristics is characterized in that carbon is added to the ceramic substrate in an amount of 100 to 5000 p.
pm. There are two types of carbon, amorphous and crystalline.Amorphous carbon can suppress a decrease in volume resistivity of a ceramic substrate at a high temperature. Since the decrease in thermal conductivity at high temperatures can be suppressed, the type of carbon can be appropriately selected according to the purpose of the substrate to be manufactured.

The amorphous carbon is, for example, C, H, O
Hydrocarbons, preferably saccharides, can be obtained by calcining in air, and graphite powder can be used as the crystalline carbon.
In addition, carbon can be obtained by thermally decomposing the acrylic resin under an inert atmosphere and then heating and pressurizing. However, by changing the acid value of the acrylic resin, it is possible to obtain a crystalline (non-crystalline) material. Can be adjusted.

The shape of the ceramic substrate is preferably a disk shape, and the diameter is preferably 200 mm or more.
mm or more is optimal. Disc-shaped ceramic substrates
This is because temperature uniformity is required, but the larger the diameter of the substrate, the more likely the temperature becomes non-uniform.

The thickness of the ceramic substrate is preferably 50 mm or less, more preferably 20 mm or less. Also, 1-5
mm is optimal. If the thickness is too thin, warpage is likely to occur when heating at a high temperature, while if it is too thick, the heat capacity becomes too large and the temperature rise / fall characteristics deteriorate.

The porosity of the ceramic substrate is preferably 0 or 5% or less. The porosity is measured by the Archimedes method. This is because a decrease in the thermal conductivity at a high temperature and the occurrence of warpage can be suppressed.

In the present invention, a thermocouple can be embedded in a ceramic substrate as needed. This is because the temperature of the resistance heating element can be measured with a thermocouple, and the temperature can be controlled by changing the voltage and current based on the data.

The size of the junction of the thermocouple metal wires is preferably equal to or larger than the diameter of each metal wire and 0.5 mm or less. With such a configuration, the heat capacity of the junction is reduced, and the temperature is accurately and quickly converted to a current value. For this reason, the temperature controllability is improved and the temperature distribution on the heated surface of the wafer is reduced. Examples of the thermocouple include J
As listed in IS-C-1602 (1980),
K-type, R-type, B-type, E-type, J-type, and T-type thermocouples are exemplified.

By using the above-mentioned hot plate unit, the whole object to be heated such as a semiconductor wafer can be heated to a uniform temperature and a predetermined temperature.

When an electrostatic electrode is provided inside a ceramic substrate constituting the ceramic heater of the present invention, it functions as an electrostatic chuck. Examples of the metal used for the electrostatic electrode include noble metals (gold, silver, platinum, and palladium),
Tungsten, molybdenum, nickel and the like are preferred.
Examples of the conductive ceramic include carbides of tungsten and molybdenum. These may be used alone or in combination of two or more.

FIG. 8A is a longitudinal sectional view schematically showing an electrostatic chuck according to the present invention, and FIG. 8B is a sectional view taken along line AA of the electrostatic chuck shown in FIG. is there. In this electrostatic chuck 60, chuck positive and negative electrostatic electrode layers 62 and 63 are embedded in a circular ceramic substrate 61, connected to through holes 68, and a ceramic dielectric film 64 is formed on the electrodes. I have.

As shown in (b), inside the ceramic substrate 61, a chuck positive electrode electrostatic layer 62 composed of a semi-circular portion 62a and a comb tooth portion 62b, and a semi-circular portion 63a and a comb Chuck negative electrode electrostatic layer 6 including tooth portion 63b
3 are arranged to face each other so as to intersect the comb portions 62b and 63b.

Further, a resistance heating element 65 and external terminals 66 are provided on the bottom surface of the ceramic substrate 61 so that an object to be heated such as the silicon wafer W can be heated. Also, although not shown in FIG.
Are connected to both ends of the resistance heating element 65 to which
An insulating layer is formed as in the case of the resistance heating element shown in FIG. Note that an RF electrode may be embedded in the ceramic substrate 61 as necessary.

The ceramic substrate having such a configuration is shown in FIG.
Are fitted into a supporting container having substantially the same structure and function as the supporting container 20 shown in FIG.
At this time, the positive and negative sides of the wiring extending from the DC power supply in the control device are connected to the chuck positive electrode electrostatic layer 62 and the chuck negative electrode electrostatic layer 63, and a DC voltage is applied. Thereby, the silicon wafer W placed on the electrostatic chuck is electrostatically attracted and heated uniformly, and in this state, it is possible to perform various processes on the silicon wafer W.

FIGS. 9 and 10 are horizontal sectional views schematically showing electrostatic electrodes of a ceramic substrate constituting another electrostatic chuck. In the ceramic substrate 71 constituting the electrostatic chuck 70 shown in FIG. 9, a semicircular chuck positive electrostatic layer 72 and a chuck negative electrostatic layer 73 are formed inside the ceramic substrate 71, as shown in FIG. In the ceramic substrate 81 constituting the electrostatic chuck 80, the chuck positive electrostatic layers 82 a and 82 b and the chuck negative electrostatic layers 83 a and 83 each having a shape obtained by dividing a circle into four inside the ceramic substrate 81.
b are formed. Also, the two positive electrode electrostatic layers 82
a, 82b and two chuck negative electrode electrostatic layers 83a, 8
3b are formed so as to cross each other. In the case of forming an electrode in which a circular electrode or the like is divided, the number of divisions is not particularly limited, and may be five or more, and the shape is not limited to a sector.

Further, as described above, when a chuck top conductor layer is provided on the surface of the ceramic substrate and a guard electrode or a ground electrode is provided as an internal conductor layer,
Functions as a chuck top plate for wafer probers.

FIG. 11 is a cross-sectional view schematically showing one embodiment of a chuck top plate for a wafer prober.
2 is a plan view, and FIG. 13 is a sectional view taken along line AA of the chuck top plate for a wafer prober shown in FIG.

In the chuck top plate for a wafer prober, a concentric groove 7 is formed on the surface of the ceramic substrate 3 having a circular shape in plan view, and a plurality of suctions for sucking a silicon wafer are partially formed in the groove 7. A hole 8 is provided, and a chuck top conductor layer 2 for connecting to an electrode of a silicon wafer is formed in a circular shape on most of the ceramic substrate 3 including the groove 7.

On the other hand, on the bottom surface of the ceramic substrate 3, a resistance heating element 4 having a concentric circular shape in a plan view is provided for controlling the temperature of the silicon wafer. The external terminal 9 is connected and fixed via a not shown). Although not shown in FIG. 11, an insulating layer is formed between both ends of the resistance heating element 4 to which the external terminals 9 are connected and between them, as in the case of the resistance heating element shown in FIG.

In order to remove stray capacitors and noise, a guard electrode 5 and a ground electrode 6 having a lattice shape as shown in FIG.
The guard electrode 5 and the ground electrode 6 are connected to external terminals (not shown) via through holes 56 and 57. Reference numeral 1 indicates an electrode non-formed portion. The reason why such a rectangular electrode non-forming portion 1 is formed inside the guard electrode 5 is to firmly bond the upper and lower ceramic substrates 3 sandwiching the guard electrode 5 therebetween.

The ceramic substrate having such a structure is fitted into a supporting container having substantially the same structure as that shown in FIG. 1 and operates as a wafer prober. In this wafer prober, after a silicon wafer on which an integrated circuit is formed is placed on a ceramic substrate 3, a probe card or the like having tester pins is pressed against the silicon wafer, and a voltage is applied while heating or cooling uniformly. A continuity test can be performed.

Next, a method for manufacturing the ceramic heater of the present invention will be described. A method for manufacturing a ceramic heater in which a resistance heating element 12 is formed on the bottom surface of a ceramic substrate will be described with reference to FIG.

(1) Step of Manufacturing Ceramic Substrate A slurry is prepared by blending a sintering aid such as yttria or a binder as necessary with the above-described nitride ceramic such as aluminum nitride, and then spray-drying the slurry. The resulting granules are put into a mold or the like and pressed into a plate or the like to form a green body. At this time, carbon may be contained.

Next, as necessary, a portion serving as a through hole 15 for inserting a lifter pin for carrying a silicon wafer and a bottomed hole 14 for embedding a temperature measuring element such as a thermocouple are formed in the formed body. And a portion to be a through hole or a recess for inserting a support pin for supporting the silicon wafer. After firing, the bottomed holes 14 and the through holes 15 may be formed in the manufactured ceramic substrate using a drill or the like.

Next, the formed body is heated, fired and sintered to produce a ceramic plate. After that, the ceramic substrate 11 is manufactured by processing into a predetermined shape, but may be a shape that can be used as it is after firing. By performing heating and firing while applying pressure, it is possible to manufacture a ceramic substrate 11 having no pores. Heating and firing may be performed at a temperature equal to or higher than the sintering temperature. Usually, after firing, a through hole 15 and a bottomed hole 14 are formed (FIG. 14A).

(2) Step of Printing Conductive Paste on Ceramic Substrate The conductive paste is generally a high-viscosity fluid composed of metal particles, resin and solvent. The conductor paste is printed on a portion where the resistance heating element is to be provided by screen printing or the like to form a conductor paste layer.
At this time, the centers of the external terminals at both ends of the circuit of the resistance heating element are provided close to each other. In addition, since the resistance heating element needs to make the entire temperature of the ceramic substrate a uniform temperature, it is preferable that the resistance heating element be printed in a concentric shape or a bent line shape, or a pattern combining a concentric shape and a bent shape. . The conductive paste layer is preferably formed such that the cross section of the resistance heating element 12 after firing has a square and flat shape.

(3) Firing of Conductive Paste The conductive paste layer printed on the bottom surface of the ceramic substrate 11 is heated and fired to remove the resin and the solvent, and sinter the metal particles.
The resistance heating element 12 is formed (FIG. 14B). The temperature of the heating and firing is preferably from 500 to 1000C. If the above-described metal oxide is added to the conductor paste, the metal particles, the ceramic substrate and the metal oxide are sintered and integrated, so that the adhesion between the resistance heating element and the ceramic substrate is improved.

(4) Formation of Metal Coating Layer A metal coating layer 120 is provided on the surface of the resistance heating element 12 (FIG. 14C). The metal coating layer 120 is formed by electrolytic plating,
Although it can be formed by electroless plating, sputtering, or the like, in consideration of mass productivity, electroless plating is optimal.

(5) Attachment of Terminals and the Like External terminals 13 for connection to a power source are attached to the end of the pattern of the resistance heating element 12 via a solder layer 18. Also, a temperature measuring element 17 such as a thermocouple is inserted into the bottomed hole 14 and sealed with a heat-resistant resin such as polyimide, ceramic, or the like (FIG. 1).
4 (d)).

(6) Covering the ends of the circuit of the resistance heating element An insulating layer is formed on both ends of the circuit of the resistance heating element 12 and between them (see FIG. 3). As a method for forming the insulating layer, for example, at this time, a method in which the contact portion is covered with a resin material in a fluidized state containing a solvent or the like and solidified by drying, and a sol solution obtained by hydrolyzing an alkoxide is dropped on both ends. After that, drying and firing method, after applying paste containing glass powder, drying and firing method, a method of forming an oxide ceramic layer by sputtering using a mask, and a coating object using a coating agent There is a method in which an oxide layer or the like is formed by a CVD method after covering an area other than a certain place. The external terminal portion does not necessarily have to be covered. Thus, the manufacture of the ceramic heater 101 is completed.

7) Installation on Support Container Next, after the ceramic substrate 11 is fitted into the heat insulating ring 21 of the support container 20, the ceramic substrate 11 is fixed to the heat insulating ring 21 using bolts 28, fixing fittings 27 and the like. And
By drawing out the conductive wires 24 and the lead wires 16 from the bottom surface of the heat shielding member 22, the hot plate unit 10 having the configuration shown in FIG. 1 is obtained.

When the ceramic heater is manufactured, if an electrostatic electrode is provided inside the ceramic substrate, the ceramic heater functions as an electrostatic chuck. In addition, a chuck top conductor layer is provided on the heating surface, and a guard electrode and a ground electrode are provided inside the ceramic substrate to function as a wafer prober chap top plate.

When the electrodes are provided inside the ceramic substrate, a metal foil or the like may be embedded inside the ceramic substrate. When a conductor layer is formed on the surface of the ceramic substrate, a sputtering method or a plating method can be used, and these may be used in combination.

The ceramic heater according to the present invention can be manufactured by a so-called green sheet method in addition to the above method. In this case, aluminum nitride powder,
A green sheet is produced by molding a composition obtained by mixing a sintering aid, a resin binder, an alcohol and the like by using a doctor blade method, and the green sheets are laminated to produce a laminate. Is fired to produce a ceramic substrate. Then, a conductive paste layer is formed on the ceramic substrate in the same manner as described above, and the resultant is baked to form a resistance heating element, thereby obtaining a ceramic heater. When a green sheet laminate is manufactured, an electrostatic electrode or the like can be formed inside the ceramic substrate by forming a conductive paste layer having a predetermined pattern on the green sheet.

Hereinafter, the present invention will be described in more detail.

EXAMPLES (Example 1) Manufacture of a ceramic heater (see FIGS. 1-3 and 14) (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 : A composition consisting of 4 parts by weight of yttria, an average particle diameter of 0.4 μm), 12 parts by weight of an acrylic resin binder and alcohol was spray-dried to produce a granular powder.

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

(3) The green body after the processing is hot-pressed at a temperature of 1800 ° C. and a pressure of 20 MPa.
An aluminum nitride sintered body having a thickness of 3 mm was obtained. next,
A disk having a diameter of 230 mm was cut out from the plate to obtain a ceramic plate (ceramic substrate 11). Next, a drilling process is performed on the plate-like body, and a through hole 15 for inserting a lifter pin for transporting a semiconductor wafer, and a bottomed hole 14 for embedding a thermocouple (diameter: 1.1 mm, depth: 2 mm) ) (FIG. 14A).

(4) On the bottom of the sintered body obtained in (3),
The conductor paste was printed by screen printing. The printing pattern was a concentric pattern as shown in FIG. 2 and a pattern in which both ends of one circuit were close to each other with an intermediate portion of the same circuit interposed therebetween. At this time, the distance between the center of the end (the center of the external terminal) and the circuit in the middle part of the resistance heating element 12 was set to 0.2 mm. As the conductor paste, Solvest PS603D manufactured by Tokuri Chemical Laboratory, which is used for forming through holes in a printed wiring board, was used.

This conductor paste is a silver-lead paste, and based on 100 parts by weight of silver, lead oxide (5% by weight), zinc oxide (55% by weight), silica (10% by weight), and boron oxide (25% by weight). % By weight) and 7.5% by weight of a metal oxide composed of alumina (5% by weight). Also,
The silver particles had an average particle size of 4.5 μm and were scaly.

(5) Next, the sintered body on which the conductive paste was printed was heated and fired at 780 ° C. to obtain silver in the conductive paste,
The lead was sintered and baked on the sintered body to form the resistance heating element 12 (FIG. 14B). The silver-lead resistance heating element 12 has a thickness of 5 μm and a width of 2.4 near its terminals.
mm, and the sheet resistivity was 7.7 mΩ / □.

(6) Next, nickel sulfate 80 g / l, sodium hypophosphite 24 g / l, sodium acetate 12 g
/ L, an aqueous solution containing boric acid 8 g / l and ammonium chloride 6 g / l in an electroless nickel plating bath (5).
Was immersed to deposit a metal coating layer 120 (nickel layer) having a thickness of 1 μm on the surface of the silver-lead resistance heating element 12 (FIG. 14C).

(7) A silver-lead solder paste (manufactured by Tanaka Kikinzoku Co., Ltd.) was printed on the terminal portion 12a for securing the connection with the power supply by screen printing to form a solder layer 18. Next, the external terminal 13 having a T-shaped cross section was placed on the solder layer 18 and heated and reflowed at 420 ° C. to attach the external terminal 13 to the terminal portion 12a of the resistance heating element. (8) A thermocouple for temperature control was inserted into the bottomed hole, filled with a polyimide resin, and cured at 190 ° C. for 2 hours.

(9) Thereafter, as shown in FIG. 2, the insulating layer 1 is coated with a silicone resin (KE3494, manufactured by Shin-Etsu Chemical Co., Ltd.) so as to continuously cover the ends of a plurality of circuits.
10 was formed. That is, a methylphenyl-based silicone resin is selectively applied to the above-mentioned range, and heated and dried and solidified at 220 ° C. in an oven.
2 and end of resistance heating element 12 (external terminal 13)
To form an insulating layer 110. At this time, the thickness of the formed insulating layer 110 was 15 μm.

(10) Next, the ceramic heater 101 obtained by the above-described process is connected to the heat insulating ring 21 of the support container 20.
After that, the ceramic plate 11 is fixed to the heat insulating ring 21 using bolts 28, fixing fittings 27 and the like, and the conductive wires 24 and the lead wires 16 are pulled out from the bottom surface of the heat shielding member 22, thereby forming the hot plate unit. Obtained.

Example 2 Manufacture of Ceramic Heater (See FIGS. 1-3 and 14) In the step (9), instead of the silicone resin, an insulating layer made of polybenzimidazole: PBI (Cerazole manufactured by Clariant) was used. Except for covering, a ceramic heater was manufactured in the same manner as in Example 1.

That is, first, the aromatic polyimide powder 8
After preparing a solution of a paste-like or viscous mixture composed of 0% by weight and 20% by weight of polyamic acid, the solution of this mixture is continuously applied to the ends of a plurality of circuits as shown in FIG. Coating was applied to form a layer of the mixture on these parts. Next, the layer of the formed mixture is heated and dried and solidified at 350 ° C. in a continuous firing furnace, and is fused to the end portion 12 a (external terminal 13) of the resistance heating element 12, the ceramic substrate 11, and the like. And

Example 3 Production of Ceramic Heater (See FIGS. 1, 5, 6, and 14) A ceramic heater was produced in the same manner as in Example 1, except for the following steps. In (4), when printing the conductor paste, as shown in FIG. 5, the printing pattern is formed by a repetitive pattern of arc-shaped bending lines divided into several circuits in the circumferential direction. The pattern had a shape concentrically expanding from the center to the outside, and the ends of adjacent circuits were adjacent patterns as shown in FIG. In this case, the center of both ends (the center of the external terminal)
And the distance from the center was set to 0.2 mm.

In (9), instead of forming an insulating layer using a silicone resin, a mixed solution consisting of 25 parts by weight of tetraethylsilicate, 0.3 parts by weight of hydrochloric acid and 23.5 parts by weight of water was used for 24 hours. Hydrolysis with stirring, after dropping on the part to be coated with the polymerized sol solution,
The insulating layer 140 was formed by baking at 780 ° C. As shown in FIG. 6, the insulating layer 140 has a shape in which all of the ends 32a of the adjacent circuits and the space between them are covered.

Example 4 Production of Electrostatic Chuck (See FIG. 8) (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama, average particle size 1.1 μm), yttria (average particle size: 0.1 μm)
4 μm) A composition obtained by mixing 4 parts by weight, 12 parts by weight of an acrylic resin binder, 0.5 parts by weight of a dispersant, and 53 parts by weight of alcohol composed of 1-butanol and ethanol is molded by a doctor blade method. As a result, a green sheet having a thickness of 0.47 mm was obtained. (2) Next, after drying the green sheet at 80 ° C. for 5 hours, punching was performed to provide a through hole for connecting a static electrode and an external terminal.

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

(4) Using a conductive paste A, a conductive paste layer having an electrostatic electrode pattern having the shape shown in FIG. 8B was formed on the surface of the green sheet. The electrostatic electrode pattern is composed of comb electrodes (62b, 63b),
2b and 63b are connected to 62a and 63a, respectively (see FIG. 8B). Further, a conductive paste B is provided in the through-hole for connecting the electrostatic electrode and the external terminal.
Was charged.

(5) Two green sheets on which the tungsten paste is not to be printed are further laminated on the upper side (on the heating side) and 48 on the lower side (on the bottom side) on the green sheet after the above-mentioned treatment. The laminate was formed by pressure bonding at a temperature of 8 ° C. and a pressure of 8 MPa.

(6) Next, the obtained laminate was degreased in a nitrogen gas at 600 ° C. for 5 hours, and then hot-pressed at 1890 ° C. and a pressure of 15 MPa for 3 hours to obtain a thickness of 3 m.
m having a diameter of 23 m.
It was cut out into a 0 mm disk shape.

(7) Ceramic substrate 6 obtained in (5) above
1 was polished with a diamond grindstone, a mask was placed on the surface, and blasting treatment with SiC or the like was performed to form a bottomed hole (diameter: 1.2 mm, depth 2.0 m) for a thermocouple on the surface.
m). (8) Further, a conductor paste was printed on the bottom surface of the ceramic substrate 61 by screen printing. The printing pattern is
A concentric pattern as shown in FIG. 2 was used, and a pattern in which both ends of one circuit were close to each other across an intermediate portion of the same circuit. At this time, the distance between the centers of the two ends of the circuit (the centers of the external terminals) and the center was set to 0.2 mm. As the conductor paste, Solvest PS603D manufactured by Tokuri Chemical Laboratory, which is used for forming through holes in a printed wiring board, was used.

This conductor paste is a silver-lead paste, and based on 100 parts by weight of silver, lead oxide (5% by weight), zinc oxide (55% by weight), silica (10% by weight), and boron oxide (25% by weight). % By weight) and 7.5% by weight of a metal oxide composed of alumina (5% by weight). Also,
The silver particles had an average particle size of 4.5 μm and were scaly.

(9) Next, the sintered body on which the conductor paste was printed was heated and fired at 780 ° C. to obtain silver in the conductor paste,
The lead was sintered and baked on the sintered body to form a resistance heating element 65. The silver-lead resistance heating element 65 had a thickness of 5 μm, a width of 2.4 mm, and a sheet resistivity of 7.7 mΩ / □ near the terminal portion. As a result, an aluminum nitride plate-shaped body 61 having a resistance heating element 65 and a chuck positive electrostatic layer 62 and a chuck negative electrostatic layer 63 having a thickness of 6 μm inside was obtained.

(10) Using a gold solder made of Ni-Au at a temperature of 700 ° C., a portion where a through hole is formed is cut out to form a blind hole and an end of a resistance heating element formed on the bottom surface. And the external terminal 66 made of Kovar was connected, and then a socket having a conductive wire was attached to the external terminal.

(11) Thereafter, although not shown in FIG. 8, the ends of the circuit of the resistance heating element including the external terminals which are close to each other are set within the range shown in FIG. Similarly, it was covered with a polyimide resin (Ube Fine, Ube Industries) to form an insulating layer. (12) Next, a plurality of thermocouples for temperature control were embedded in the bottomed holes, and the manufacture of the electrostatic chuck 60 having the resistance heating elements and the electrostatic electrodes 62 and 63 was completed.

(13) Next, the electrostatic chuck 6 is attached to the support container.
The electrostatic chuck unit was obtained by inserting and fixing 0.

(Example 5) Production of chuck top plate for wafer prober (see FIG. 11) (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), yttria (average particle size: 0.1 μm)
4 μm) A composition obtained by mixing 4 parts by weight, 12 parts by weight of an acrylic resin binder, 0.5 parts by weight of a dispersant, and 53 parts by weight of alcohol composed of 1-butanol and ethanol is molded by a doctor blade method. As a result, a green sheet having a thickness of 0.47 mm was obtained. (2) Next, after drying this green sheet at 80 ° C. for 5 hours, punching was performed to provide a through hole for connecting an electrode and an external terminal.

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

(4) The conductive paste A was printed on the surface of the green sheet by a screen printing method to form a grid-shaped guard electrode print layer (see FIG. 13) and a ground electrode print layer. Further, the through-hole for through-hole for connecting an external terminal was filled with a conductive paste B to form a filling layer for through-hole. Then, 50 green sheets on which the conductive paste is printed and 50 green sheets on which the conductive paste is not printed are stacked,
They were integrated under a pressure of MPa.

(5) The integrated laminate is heated at 600 ° C. for 5 hours.
After degreasing for 1 hour, hot pressing was performed at 1890 ° C. and a pressure of 15 MPa for 3 hours to obtain an aluminum nitride plate having a thickness of 3 mm. The plate was cut out into a circular shape having a diameter of 230 mm to obtain a ceramic substrate. In addition, the size of the through hole was 0.2 mm in diameter and 0.2 mm in depth. The thickness of the guard electrode and the ground electrode is 10 μm.
m, the formation position of the guard electrode in the sintered body thickness direction is 1 mm from the wafer mounting surface, while the formation position of the ground electrode in the sintered body thickness direction is 1.2 mm from the wafer mounting surface.
mm.

(6) After polishing the ceramic substrate obtained in the above (5) with a diamond grindstone, a mask is placed thereon.
By blasting with SiC or the like, a bottomed hole for attaching a thermocouple and a groove
m, depth 0.5 mm).

(7) Further, a conductive paste was printed on the back surface (bottom surface) facing the chuck surface where the groove was formed to form a conductive paste layer for a resistance heating element. The printing pattern was a concentric pattern as shown in FIG. 2 and a pattern in which both ends of the circuit of the resistance heating element were close to each other. At this time, the distance between the centers of the two ends of the circuit (the centers of the external terminals) and the center was set to 0.2 mm.

As this conductive paste, Solvest PS603D manufactured by Tokuri Chemical Laboratory, which is used for forming through holes in a printed wiring board, was used. That is, this conductive paste is a silver / lead paste, and a metal oxide composed of lead oxide, zinc oxide, silica, boron oxide, and alumina (the weight ratio of each is 5/55/10/25 /
5) is contained in an amount of 7.5% by weight based on the amount of silver. The silver in the conductive paste has an average particle size of 4.
A 5 μm scale was used.

(8) A ceramic substrate on which a circuit is formed by printing a conductive paste on the bottom surface is heated and fired at 780 ° C. to sinter silver and lead in the conductive paste and to bake the ceramic substrate. A resistance heating element having a pattern similar to the pattern shown was formed. Next, this ceramic substrate was treated with nickel sulfate 30 g / l, boric acid 3
0 g / l, 30 g / l of ammonium chloride, and 60 g / l of Rochelle salt in an electroless nickel plating bath comprising an aqueous solution containing the conductive paste. Was deposited and coated, followed by annealing at 120 ° C. for 3 hours. The resistance heating element including the nickel layer thus obtained has a thickness of 5 μm.
m, the width was 2.4 mm, and the sheet resistivity was 7.7 mΩ / □.

(9) Next, each layer of Ti, Mo, and Ni was sequentially laminated on the chuck surface where the groove was formed by a sputtering method. In this sputtering, SV-4540 manufactured by Nippon Vacuum Engineering Co., Ltd. was used as an apparatus, and the pressure was 0.6 P.
a, temperature: 100 ° C., power: 200 W, processing time: 30
The sputtering was performed under the conditions of seconds to 1 minute, and the sputtering time was adjusted depending on each metal to be sputtered. The obtained film had a Ti of 0.3 μm and a Mo of X-ray spectrometer image.
Was 2 μm and Ni was 1 μm.

(10) The ceramic substrate obtained in the above (9) was treated with 30 g / l of nickel sulfate, 30 g / l of boric acid,
Ammonium chloride 30g / l, Rochelle salt 60g / l
Is immersed in an electroless nickel plating bath composed of an aqueous solution containing, and a nickel layer having a boron content of 1% by weight or less (thickness: 7 μm) is deposited on the surface of the groove formed on the chuck surface. For 3 hours. Furthermore, potassium cyanide 2 is applied to the surface of the ceramic substrate (the chuck surface side).
g / l, 75 g / l ammonium chloride, 50 g / l sodium citrate, and 10 g / l sodium hypophosphite for 1 minute at 93 ° C. in an electroless gold plating solution. Further, a 1-μm-thick gold plating layer was further laminated on the nickel plating layer to form a chuck top conductor layer.

(11) Next, an air suction hole that escapes from the groove to the back surface was drilled and drilled, and a blind hole for exposing the through hole was provided. Ni-Au
An external terminal made of Kovar was connected by heating and reflowing at 970 ° C. using a gold solder made of an alloy (Au 81.5 wt%, Ni 18.4 wt%, impurity 0.1 wt%).
External terminals made of Kovar were formed on the resistance heating element via a solder alloy (tin 9 / lead 1).

(12) Thereafter, as shown in FIG. 1, an insulating layer 110 made of an oxide-based glass material is continuously formed between adjacent ends of the circuit of the resistance heating element including the external terminals and between them. Formed. That is, first, PbO: 30 wt%, SiO _2: 50 wt%, B ₂ O _3: 15 wt%, A
A paste-like mixture was prepared by adding 3 parts by weight of a vehicle and 10 parts by weight of a solvent to 87 parts by weight of a glass powder having a composition consisting of ₃ % by weight of l ₂ O _{3 and 2} % by weight of Cr ₂ O ₃ .

Next, using this paste-like mixture, screen printing was performed so as to cover the end portion (external terminal) of the resistance heating element 12 and the surface of the ceramic substrate 11 therebetween, thereby forming a layer of the paste-like mixture. Thereafter, the paste mixture is dried and fixed at 120 ° C.
By heating at 80 ° C. for 10 minutes, it was fused to the lower portion of the external terminal and the surface of the ceramic substrate 11 to form an insulating layer. Thereafter, a socket having a conductive wire was attached to the external terminal.

(13) In order to control the temperature, a plurality of thermocouples are embedded in the bottomed holes, and the surface of the chuck top conductor layer 2 is
Has a guard electrode 5 and a ground electrode 6 inside,
The manufacture of the wafer prober chuck top plate 201 having the resistance heating element 4 formed on the bottom surface has been completed. (14) Thereafter, the wafer prober chuck top plate 201 was fitted into the supporting container and fixed to obtain a wafer prober.

(Embodiment 6) In this embodiment, a glass paste (manufactured by Shoei Chemical Industry Co., Ltd.) is applied to the entire bottom surface on which the resistance heating element is formed, and heated at 700 ° C. to form an insulating layer. A ceramic heater was manufactured in the same manner as in Example 1 except that the surface was polished.

Comparative Example 1 Production of Ceramic Heater A ceramic heater was produced in the same manner as in Example 1 except that the end of the circuit of the resistance heating element was not covered with the insulating layer in (9). (Comparative Example 2) Manufacture of ceramic heater In (4), the pattern of the resistance heating element to be printed was the same as that of Example 3 except that the distance between the centers of both ends of the adjacent circuit was 23 mm. Thus, a ceramic heater was manufactured.

The ceramic heaters according to Examples 1 to 5 and Comparative Examples 1 and 2 were evaluated as described below. Table 1 shows the results.

[0146]Evaluation method  (1) Measurement of temperature distribution on heating surface The ceramic heaters according to Examples and Comparative Examples were energized.
To 200 ° C, and the heating surface of the ceramic heater
The temperature distribution was measured using a thermoviewer (IR62 manufactured by Nippon Datum).
012-0012). As shown in Table 1
Is the temperature difference between the highest temperature and the lowest temperature. (2) Presence or absence of short circuit The ceramic heaters according to the example and the comparative example were energized.
Heat cycle to 200 ℃ and return to room temperature
Test 100 times to see if there is a short circuit at the end
Was.

(3) Presence or absence of occurrence of migration The hot plate unit was heated to 200 ° C. at 100% humidity and energized for 48 hours, and a fluorescent X-ray analyzer (Shimadzu Corporation) was used to check for metal diffusion between the resistance heating elements. EPM-81
0S).

[0148]

[Table 1]

As a result, as shown in Table 1, in the ceramic heaters according to Examples 1 to 6 and Comparative Example 2, no short circuit occurred because the insulating layer having sufficient insulating properties was formed. However, in Comparative Example 1, a short circuit occurred because no insulating layer was present, and migration was also observed. Therefore, it is considered that this short circuit is caused by migration of the metal. Further, as shown in Table 1, the ceramic heaters of Examples 1 to 6 had a small temperature difference on the heating surface, whereas Comparative Example 2 had a large temperature difference on the heating surface. In Comparative Example 1, the temperature difference until a short circuit occurred was small.

[0150]

As described above, since the ceramic heater according to the present invention is configured as described above, the temperature of the heating surface on the ceramic substrate can be made uniform, and the temperature of the semiconductor wafer or the like can be reduced. The heating object can be heated uniformly. Also, no short circuit occurs between the ends of the resistance heating element or between the end and the middle part of the circuit, and the connection reliability can be maintained even when used for a long time.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an example of a hot plate unit using a ceramic heater according to the present invention.

FIG. 2 is a bottom view of the ceramic heater of the hot plate unit shown in FIG.

3A is a partially enlarged cross-sectional view schematically showing an example of a circuit end of a resistance heating element in the ceramic heater according to the present invention, and FIG. 3B is a bottom view thereof.

FIG. 4A is a partially enlarged cross-sectional view schematically showing another example of the end of the circuit of the resistance heating element in the ceramic heater according to the present invention, and FIG. 4B is a bottom view thereof.

FIG. 5 is a plan view showing another example of the portion of the ceramic heater of the hot plate unit shown in FIG. 1;

6A is a partially enlarged sectional view schematically showing an end of a circuit of a resistance heating element in the ceramic heater shown in FIG. 5, and FIG. 6B is a bottom view thereof.

FIG. 7A is a partially enlarged cross-sectional view schematically showing another example of the end of the circuit of the resistance heating element in the ceramic heater according to the present invention, and FIG. 7B is a bottom view thereof.

8A is a longitudinal sectional view schematically showing a ceramic heater when the ceramic heater of the present invention is used for an electrostatic chuck, and FIG. 8B is a longitudinal sectional view of the ceramic heater shown in FIG. FIG. 3 is a sectional view taken along line AA.

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

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

FIG. 11 is a cross-sectional view schematically showing a case where the ceramic heater of the present invention is used as a chuck top plate for a wafer prober.

FIG. 12 is a bottom view of the wafer prober chuck top plate shown in FIG. 11;

FIG. 13 is a sectional view taken along line AA of the chuck top plate for a wafer prober shown in FIG. 11;

FIGS. 14A to 14D are cross-sectional views schematically illustrating an example of a method for manufacturing a ceramic heater according to the present invention.

15A is a partially enlarged cross-sectional view schematically showing another example of the end of the circuit of the resistance heating element in the ceramic heater according to the present invention, and FIG. 15B is a bottom view thereof.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductor layer non-formed portion 2 chuck top conductor layer 3, 11, 31, 61 ceramic substrate 11a heating surface 11b bottom surface 4, 12, 32, 65 resistance heating element 5 guard electrode 6 ground electrode 7 groove 8 suction hole 9, 13, 66 External terminal 10 Hot plate unit 12a, 32a, 42a Resistance heating element end 13, 53, 58, 66 External terminal 14 Bottom hole 15 Through hole 16 Lead wire 17 Temperature measuring element 18 Solder layer 20 Support container 21 Heat insulation ring 22 Heat shielding member 24 Conductive wire 25 Socket 26 Refrigerant introduction tube 27 Fixing bracket 28 Bolt 29 Guide tube 30, 40, 101 Ceramic heater 56, 57, 68 Through hole 60, 70, 80 Electrostatic chuck 62, 72, 82a, 82b Chuck Electrode layer 63, 73, 83a, 83b Chuck negative electrode layer 64 Lamic dielectric film 22a Through hole 110, 130, 140, 150 Insulating layer 120, 320 Metal coating layer 201 Chuck top plate for wafer prober

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/66 H01L 21/66 H H05B 3/10 H05B 3/10 C 3/16 3/16 3/20 328 3/20 328 393 393 F term (reference) 3K034 AA02 AA06 AA08 AA10 AA21 AA22 AA34 BB06 BB14 BC03 BC12 BC24 BC29 CA02 CA15 CA26 CA39 DA04 DA08 EA07 HA01 HA10 JA01 JA02 3K092 PP20 QA05 QB18 Q20 QA05 QB18B QC32 QC38 QC52 QC62 RF03 RF11 RF17 RF22 TT40 UA05 UA17 UA18 UB04 VV22 VV25 4M106 AA01 BA01 DD30 DH44 DH46 DJ02

Claims (6)

[Claims] 1. A resistance heating element comprising one or a plurality of circuits having an external terminal at an end thereof is formed on a surface of a ceramic substrate, and is provided between the external terminals, between the external terminal and the circuit, and between the circuits. A ceramic heater, wherein at least one set is provided in close proximity, and an insulator is interposed between the external terminals provided close to each other, between the external terminals and the circuit, and between the circuits. 2. The ceramic heater according to claim 1, wherein the insulator is made of a resin. 3. The ceramic heater according to claim 1, wherein the insulator is made of an oxide ceramic. 4. The ceramic heater according to claim 3, wherein the oxide ceramic is an oxide glass. 5. The ceramic heater according to claim 3, wherein the oxide ceramic is made from a metal oxide sol or metal alkoxide. 6. The ceramic heater according to claim 1, wherein the ceramic substrate is made of a nitride ceramic or a carbide ceramic.