JP2002025756A - Hot plate for apparatus for manufacturing and inspecting semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot plate, whose base board of ceramic is supported in such a way that its side faces and bottom peripheries are not contacting at all with a supporting vessel. SOLUTION: The ceramic base board of this hot plate is structured, so that a resistance type heating element is provided at the surface or inside and is installed in the supporting vessel, where the base board is supported by a supporting member provided inside the vessel, and the contacting part of the supporting member with the base board is positioned inside the region, where the heating element is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a hot plate (ceramic heater) used for the manufacture and inspection of semiconductors.
About.

[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 heater or a wafer prober using a metal base material such as stainless steel or an aluminum alloy is used. I have been.

[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.

In addition, by changing the voltage or the amount of current applied to the resistance heating element, the temperature of a surface to be heated (hereinafter, referred to as a heating surface) such as a silicon wafer is controlled. 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.

Japanese Patent Application Laid-Open No. H11-40330 discloses that a substrate made of a nitride ceramic or a carbide ceramic having a high thermal conductivity and a high strength is used as a substrate, and the surface of a plate made of these ceramics is coated with a metal. There has been proposed a ceramic substrate provided with a resistance heating element formed by sintering particles.

FIG. 7 is a cross-sectional view schematically showing a hot plate in which a ceramic substrate having such a configuration is installed in a supporting container. In this hot plate 20, the bottom surface 4
A disk-shaped ceramic substrate 41 having a resistance heating element 42 formed on 1b is fitted into the annular supporting container main body 21 via a heat insulating ring 25, and an end of the resistance heating element 42 is provided with a solder layer. The external terminal 43 is connected via a (not shown) or the like.

A substrate receiving portion 21 a for supporting the ceramic substrate 41 is provided inside a lower portion of the supporting container body 21.
On the other hand, a bottomed cylindrical heat shielding member 26 is attached to the lower surface of the support container body 21 using bolts 28 and fixed.

The bolt 28 also has a function of fixing the holding metal member 27, and the ceramic metal member 41 is pressed against the substrate receiving portion 21 a via the heat insulating ring 25 by the holding metal member 27, and is fixed. I have.

At the bottom of the heat shielding member 26, a refrigerant introduction pipe 19 is provided. Through the refrigerant introduction pipe 19, the refrigerant is introduced into the inside of the support container 20, and the heat shielding member 26 It is discharged through the provided through hole 26a,
At the time of cooling after heating, the ceramic substrate 41 is cooled.

When power is supplied to the hot plate 20 having such a configuration, the resistance heating element generates heat, and as a result, the silicon wafer 9 and the like placed on the ceramic substrate can be heated to a predetermined temperature.

[0011]

However, in the hot plate 20 having the above-described structure, the outer periphery of the side surface or the bottom surface of the ceramic substrate is in contact with the support container main body 21 via the heat insulating ring 25 or the like. Heat easily escapes.

In order to prevent such heat dissipation, a heat insulating ring 25 having heat insulating performance is interposed between the ceramic substrate 41 and the support container 20.
When 1, for example, becomes high temperature of about 300 ° C.,
Again, it was difficult to completely prevent heat from escaping through this insulating ring 25.

Further, since the resistance heating element 42 is not formed on the side surface or the bottom surface of the ceramic substrate 41, the temperature is more likely to be lowered due to the dissipation of heat. Therefore, a so-called cooling spot (local portion) is formed in this portion. In this case, there is a problem that it is difficult to uniformly heat an object to be heated such as a silicon wafer.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, in order to prevent heat radiation from the side surfaces and the outer periphery of the bottom surface of the ceramic substrate where no resistance heating element is formed, the side surfaces of the ceramic substrate and The present inventors have found a method of supporting a ceramic substrate without bringing the outer peripheral portion of the bottom surface into contact with the supporting container at all, and have completed the present invention.

[0015]

That is, the present invention provides a hot plate in which a ceramic substrate having a resistance heating element formed on the surface or inside thereof is disposed in a support container. It is supported by a support member installed inside the support container, and a contact portion between the support member and the ceramic substrate is present inside an area in which the resistance heating element is formed. Hot plate.

According to the hot plate, the outer peripheral portion of the side surface and the bottom surface of the ceramic substrate is not in contact with the heat insulating ring or the supporting container at all, and is in contact with air like other portions. Does not dissipate more heat than the other parts, and therefore no cooling spots occur in these parts.

Further, since the contact portion between the support member and the ceramic substrate exists inside the region where the resistance heating element is formed, there is some escape of the radiation through the support member. However, by controlling the amount of heat generated by the resistance heating element, heat dissipation from the support member can be compensated. Therefore, no cooling spot is generated on the ceramic substrate.

In the hot plate, the support member is preferably made of an elastic material. By supporting the ceramic substrate with an elastic body, the elastic body absorbs shocks even when a sudden load is applied to the ceramic substrate, preventing damage to a heated object such as a ceramic substrate or a silicon wafer. Because it can be.

As the elastic body, a plate spring or a coil spring can be used. Further, as the material of the coil spring or the plate-shaped spring, a metal may be used. As the metal, for example, stainless steel, Inconel, steel, aluminum,
Nickel, copper and the like can be mentioned.

Of these, metal springs are desirable. This is because the metal spring has heat resistance and thus has excellent durability even when used as a hot plate for high temperature. In the present invention, the support member may be ceramic. This is because ceramics have relatively lower thermal conductivity than metals and are superior in heat resistance.

The ceramics include alumina, silica, cordierite, zirconia, SiC and AlN.
At least one selected from the following can be used.
Of these, alumina is preferred. further,
The surface of the contact portion between the support member and the ceramic substrate is JI
In SR0601, Rmax is desirably 0.1 μm or more. This is because if Rmax is less than 0.1 μm, the contact area becomes large, and a cooling spot is easily generated on the heating surface.

The surface of the contact portion between the support member and the ceramic substrate is the contact surface on the support member side or the contact surface on the ceramic substrate side, but is both the contact surface on the support member side and the contact surface on the ceramic substrate side. You may. Examples of the surface roughening method include a polishing treatment and a sandblasting treatment.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The hot plate of the present invention is a hot plate in which a ceramic substrate having a resistance heating element formed on its surface or inside is disposed in a support container. It is supported by a support member installed inside a support container, and a contact portion between the support member and the ceramic substrate exists inside a region where the resistance heating element is formed. .

Hereinafter, the hot plate of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a bottom view schematically showing an example of the hot plate of the present invention, and FIG.
FIG. 3 is a plan view of the hot plate shown in FIG.

The ceramic substrate 41 is formed in a disk shape, and the resistance heating element 42 is formed on the bottom surface of the ceramic substrate 41 in a concentric pattern. In addition, these resistance heating elements 42 are formed such that double concentric circles close to each other are one.
The circuits are connected as a single line as a set of circuits. By forming the resistance heating element having such a pattern, the temperature of the heating surface 41a can be made uniform.

An external terminal 43 is connected to an end of the resistance heating element 42 via a solder layer (not shown) or the like, and the socket 23 having the conductive wire 14 is attached to the external terminal 43. The conductive wire 14 is drawn out of the support container 11 and is connected to a power source (not shown).

A plurality of through holes 45 for inserting lifter pins used for carrying a silicon wafer or the like are formed in a portion near the center, and a through hole communicating with these is formed in the bottom of the support container 11. A hole is formed.

On the other hand, a bottomed hole 44 for inserting a temperature measuring element 47 such as a thermocouple is formed in the bottom surface of the ceramic substrate 41, and a wiring 46 is led out from the temperature measuring element 47 to form a bottom portion of the support container 11. Through the through hole 11a.

At the bottom of the support container 11, a plurality (four) of slightly bent support members 12, one end of which is fixed by a fixture 18, is installed in an inclined state. A concave portion 49 is provided on the bottom surface of the ceramic substrate 41.
The upper end of the support member 12 is inserted into the concave portion 49, and the ceramic substrate 41 is supported and fixed using this portion as a fulcrum.

The support member 12 is formed of a metal spring such as stainless steel, inconel, steel or the like, and has a concave portion (contact portion) at a position crossing the center of the ceramic substrate 41. The number of the support members 12 is not particularly limited as long as the number is three or more. However, it is preferable that the contact portions are formed so as to be rotated with respect to the center of the ceramic substrate 41.

The support member 12 may be formed of ceramic or the like. This is because the heat conductivity is low and heat can be prevented from escaping from the ceramic substrate 41. A through hole or the like may be provided inside the resistance heating element forming region of the ceramic substrate, and the ceramic substrate may be supported and fixed by inserting a support member into the through hole.

A coolant inlet pipe 19 is fixed to the bottom of the support container 11 as in the case of the conventional hot plate 20, so that it can be cooled.

As described above, the ceramic substrate 41
A plurality of through holes 45 for inserting the lifter pins are provided. By supporting the silicon wafer 9 with the plurality of lifter pins, the silicon wafer 9 is separated from the upper surface of the ceramic substrate 41 by a certain distance. And heating can be performed.

Further, a through hole or a concave portion is formed in the ceramic substrate 41, and a pin having a spire or a hemispherical tip is inserted and fixed into the through hole or the like with the support pin slightly projecting from the ceramic substrate 41. The silicon wafer 9 is placed on the ceramic substrate 4
1 can be placed at a certain distance from the upper surface.

In the hot plate 10 of the present invention, the ceramic substrate 41 is supported inside the region where the resistance heating element 42 is formed by the support member 12 provided at the bottom of the support container 11 as described above. Even if there is some heat dissipation from that portion, by controlling the amount of heat generated by the resistance heating element 42, it is possible to prevent a cooling spot from being generated.

The outer periphery of the side surface and the bottom surface of the ceramic substrate 41 is in contact with air, like the other portions, and therefore,
Heat dissipation from these portions does not become particularly large, and the heating surface 41a of the ceramic substrate can be made to have a uniform temperature. Therefore, by using the hot plate 10 of the present invention, an object to be heated such as the silicon wafer 9 can be uniformly heated.

FIG. 3 is a sectional view schematically showing another embodiment of the hot plate of the present invention. In the hot plate 50, the ceramic substrate 51 is formed in a disk shape, and the resistance heating element 52 is provided inside the ceramic substrate 51 with a pattern similar to the pattern shown in FIG. 1, that is, a concentric pattern. It is formed with.

A through hole 58 is formed directly below the end of the resistance heating element 52, and a blind hole (not shown) for exposing the through hole 58 is formed on the bottom surface 51b.
The external terminal 53 is inserted into the blind hole, and is joined with a brazing material (not shown) or the like. And the external terminal 5
3, a socket 23 having a conductive wire 14 is attached, and the conductive wire 14 is connected to a power supply (not shown).

As in the case of the hot plate 10 shown in FIG.
Is fixed with one end fixed by the fixture 18. On the other hand, the upper end of the support member 12 is inserted into the concave portion 59 formed on the bottom surface of the ceramic substrate 51, and the ceramic substrate 51 is supported. I have.

Also in this hot plate 50, since the supporting member 12 supports the ceramic substrate 51 inside the region where the resistance heating element 52 is formed, even if there is some heat dissipation from that portion, the resistance is reduced. By controlling the amount of heat generated by the heating element 52, it is possible to prevent a cooling spot from being generated, and to uniformly heat an object to be heated such as the silicon wafer 9 or the like.

FIG. 4 is a sectional view schematically showing still another embodiment of the hot plate of the present invention. in this case,
The configuration is the same as that of the hot plate shown in FIG. 1 except that the ceramic substrate 41 is supported by a columnar alumina support member 62. Since the hot plate having the above-described configuration uses the alumina support member 62 having a lower thermal conductivity than metal, the temperature of the heating surface of the ceramic substrate 41 becomes more uniform.

As the pattern of the resistance heating element, in addition to the concentric shape shown in FIG. 1, a single pattern such as a spiral shape and an eccentric shape, a combination of a concentric shape and a bent line shape, or a spiral shape and an eccentric shape A combination of the shape and the bent line shape can be given. Further, the resistance heating element may have a spiral shape.

In the hot plate, the number of circuits composed of the resistance heating elements is not particularly limited as long as it is one or more. However, in order to uniformly heat the heating surface, it is preferable that a plurality of circuits are formed. Preferably, a combination of a plurality of concentric circuits and a bent line circuit is preferred. In addition, as shown in FIGS. 1 and 3, in the hot plate of the present invention, the resistance heating element may be formed on the bottom surface or may be formed inside the ceramic substrate.

When the resistance heating element is formed inside the ceramic substrate, its formation position is not particularly limited.
It is preferable that at least one layer is formed at a position from the bottom surface of the ceramic substrate to 60% of its thickness. This is because heat is diffused while propagating to the heating surface, and the temperature on the heating surface tends to be uniform.

When forming a resistance heating element inside or on the bottom of the ceramic substrate, it is preferable to use a conductor paste made of metal or conductive ceramic. That is, when a resistance heating element is formed inside a ceramic substrate, a conductive paste layer is formed on a green sheet, and then the green sheet is laminated and fired to form a resistance heating element inside. On the other hand, when the resistance heating element is formed on the surface, usually, after firing, a ceramic substrate is manufactured, a conductive paste layer is formed on the surface, and the firing is performed to form the resistance heating element.

The above-mentioned conductor 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.

Although the shape of the metal particles is 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.

It is not clear why the mixing of the metal oxide with the ceramic substrate improves the adhesion to the ceramic substrate, but the surface of the metal substrate or the surface of the 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. The area resistivity when the resistance heating element is formed using the conductor paste having such a configuration is preferably 1 to 45 mΩ / □.

If the area resistivity exceeds 45 mΩ / □, the amount of heat generated becomes too large with respect to the applied voltage, and it is difficult to control the amount of heat generated in a ceramic substrate provided with a resistance heating element on the surface. . The amount of metal oxide added is 1
If the content is 0% by weight or more, the sheet resistivity exceeds 50 mΩ / □, the amount of generated heat becomes too large, temperature control becomes difficult, and the uniformity of the temperature distribution decreases.

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

The metal used for forming the metal coating layer is not particularly limited as long as it is a non-oxidizing metal.
Specifically, for example, gold, silver, palladium, platinum, nickel and the like can be mentioned. These may be used alone or in combination of two or more. Of these, nickel is preferred. When the resistance heating element is formed inside the ceramic substrate, no coating is required because the surface of the resistance heating element is not oxidized. The ceramic substrate of the present invention is desirably used at a temperature of 100 ° C. or higher.
It is more desirable to use at a temperature of 00 ° C or higher.

The material of the ceramic substrate constituting the hot plate of the present invention 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.

[0062] 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.

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 ceramic substrate has a brightness of JIS Z
It is desirable that the value based on the rule of 8721 is N4 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 set to 0 for an ideal black lightness, 10 for an ideal white lightness, and a 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 has a carbon content of 100 to 5000 p in the ceramic substrate.
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. Further, 1 to 5 mm is optimal. If the thickness is too thin, warpage tends to occur when heating at high temperature,
On the other hand, if the thickness is too large, the heat capacity becomes too large, and the temperature raising / lowering 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.

The hot plate of the present invention is an apparatus mainly used for manufacturing semiconductors and inspecting semiconductors.
Although only a resistance heating element is provided on a ceramic substrate, when an electrostatic electrode is provided inside the ceramic substrate, it functions as an electrostatic chuck, a conductor layer is provided on the surface of the ceramic substrate, and a ceramic substrate is provided. When a guard electrode or a ground electrode is provided inside, it functions as a wafer prober.

Next, a method for manufacturing a hot plate having a resistance heating element formed on the bottom surface will be described with reference to FIGS.

(1) Step of Producing Ceramic Substrate A slurry is prepared by blending a sintering aid such as yttria or a binder as necessary with the above-mentioned nitride ceramic such as aluminum nitride, and then this slurry is spray-dried. 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, the formed body is heated, fired and sintered to produce a ceramic plate. After that, the ceramic substrate 41 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 41 having no pores. Heating and firing may be performed at a temperature equal to or higher than the sintering temperature.

Next, a through hole 45 for inserting a lifter pin for carrying a silicon wafer, a bottomed hole 44 for embedding a temperature measuring element such as a thermocouple, and a silicon wafer A recess (not shown) or the like for burying a support pin for supporting the substrate is formed (FIG. 5A). Although not shown in FIG. 5, a concave portion (see FIG. 1) for inserting the support member is formed.

(2) Step of Printing Conductive Paste on Ceramic Substrate Using the above-described conductive paste, printing is performed on a heating element pattern by a method such as screen printing to form a conductive paste layer. Since the resistance heating element needs to keep the entire temperature of the ceramic substrate at a uniform temperature, the resistance heating element may be printed in a concentric shape as shown in FIG. 1 or in a pattern in which a concentric shape and a bent line are combined. preferable. The conductive paste layer is preferably formed such that the cross section of the resistance heating element 42 after firing has a rectangular and flat shape.

(3) Firing of Conductive Paste The paste layer printed on the bottom surface of the ceramic substrate 41 is heated and fired to remove the resin and the solvent, and sinter the metal particles. The heating element 42 is formed (FIG. 5B). 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 metal oxide, and the ceramic substrate 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 Next, a metal coating layer 420 is provided on the surface of the resistance heating element 42 (FIG. 5C). The metal coating layer 420 can be formed by electrolytic plating, electroless plating, sputtering, or the like. However, considering mass productivity, electroless plating is optimal.

(5) Attachment of Terminals and the Like An external terminal 43 for connection to a power supply is attached to the end of the pattern of the resistance heating element 42 using solder 470 or the like. Further, a temperature measuring element (thermocouple) 48 is inserted into the bottomed hole 44, and sealed with a heat-resistant resin such as polyimide or ceramic to form the hot plate 10 (FIG. 5D). Then, this hot plate is placed in the support container 11 having the support member 12 as shown in FIG. 1, and the lead wire extending from the socket is connected to a power source, thereby completing the production of the hot plate.

When manufacturing the hot plate, an electrostatic chuck can be manufactured by providing an electrostatic electrode inside the ceramic substrate, and a chuck top conductor layer is provided on the heating surface, and the inside of the ceramic substrate can be manufactured. A wafer prober can be manufactured by providing a guard electrode and a ground electrode on the substrate.

When 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.

Next, a method for manufacturing a hot plate having a resistance heating element inside a ceramic substrate will be described with reference to FIGS. 6 (a) to 6 (d).

(1) Green Sheet Preparation Step First, a paste is prepared by mixing a nitride ceramic powder with a binder, a solvent, and the like, and a green sheet is prepared using the paste. Aluminum nitride or the like can be used as the above-mentioned ceramic powder, and a sintering aid such as yttria may be added as necessary. Further, when producing a green sheet, crystalline or amorphous carbon may be added.

The binder is preferably at least one selected from an acrylic binder, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol.
Further, as the solvent, at least one selected from α-terpineol and glycol is desirable.

The paste obtained by mixing these is formed into a sheet by a doctor blade method to form a green sheet 5.
00 is produced. The thickness of the green sheet 500 is 0.
1-5 mm is preferred. Next, in the obtained green sheet, if necessary, a portion serving as a through hole for inserting a support pin for supporting the silicon wafer, and a through hole for inserting a lifter pin for carrying the silicon wafer or the like. A portion serving as a bottomed hole for embedding a temperature measuring element such as a thermocouple, a portion 280 serving as a through hole for connecting a resistance heating element to an external terminal, and the like are formed. The above processing may be performed after forming a green sheet laminate described later.

(2) Step of Printing Conductive Paste on Green Sheet A conductive paste layer 520 made of a conductive paste is formed on the green sheet 500 using the above-described conductive paste. In addition, a portion serving as a through hole is filled with a conductive paste to form a filling layer 580.

These conductive pastes contain metal particles or conductive ceramic particles. The material of the metal particles includes, for example, tungsten or molybdenum, and the conductive ceramic includes, for example, tungsten carbide or molybdenum carbide.

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

As such a conductor paste, 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 kind of binder selected from acrylic, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol And a composition (paste) obtained by mixing 1.5 to 10 parts by weight of at least one solvent selected from α-terpineol and glycol.

(3) Green Sheet Laminating Step The green sheet 500 on which the conductive paste or the like prepared in the above step (1) is not printed is replaced with a green sheet having the conductive paste layer 220 or the like prepared in the above step (2). The sheet 500 is laminated above and below (FIG. 6A). At this time, the number of green sheets 500 stacked on the upper side is made larger than the number of green sheets 500 stacked on the lower side, and the formation position of the resistance heating element 52 is decentered toward the bottom. Specifically, the number of layers of the upper green sheet 500 is 20 to 50.
The number of sheets of the lower green sheet 500 is 5 to 20.
Sheets are preferred.

(4) Green Sheet Laminate Firing Step The green sheet laminate is heated and pressurized to sinter the green sheet 500 and the internal conductor paste to produce the ceramic substrate 51 (FIG. 6B). ). The heating temperature is preferably from 1000 to 2000 ° C.,
10-20 MPa is preferable. Heating is performed in an inert gas atmosphere. As the inert gas, for example, argon,
Nitrogen or the like can be used.

The obtained ceramic substrate 51 is provided with a through hole 55 for inserting a lifter pin, a bottomed hole 54 for inserting a temperature measuring element, a blind hole 57 for inserting an external terminal 53, and the like. (FIG. 6 (c)). The through-hole 55, the bottomed hole 54, and the blind hole 57 can be formed by performing blast processing such as drilling or sand blasting after surface polishing.

Next, the external terminal 53 is connected to the through hole 58 exposed from the blind hole 57 using a gold solder or the like (FIG. 6).
(D)). Further, although not shown, the external terminal 53
For example, a socket having a conductive wire is detachably attached. The heating temperature is 90 to 45 in the case of soldering.
0 ° C. is preferred, and 900 ° C. in the case of brazing material treatment.
~ 1100 ° C is preferred. Further, a thermocouple or the like as a temperature measuring element is sealed with a heat-resistant resin to form a hot plate.

(5) Thereafter, the ceramic substrate 51 having the resistance heating element 52 therein is mounted on the support container 11 having the support member 12 shown in FIG. 3, and the lead wire extending from the socket is used as a power supply. The connection completes the production of the hot plate.

When the hot plate is manufactured, an electrostatic chuck can be manufactured by providing an electrostatic electrode inside the ceramic substrate, and a chuck top conductor layer is provided on the heating surface, and By providing a guard electrode and a ground electrode inside, a wafer prober can be manufactured.

When electrodes are provided inside the ceramic substrate, a conductive paste layer may be formed on a green sheet in a pattern such as an electrostatic electrode or a guard electrode, and may be laminated and fired. In the case where a conductor layer is formed on the surface of the ceramic substrate, the conductor layer may be formed by using a sputtering method or a plating method after manufacturing the ceramic substrate. At this time, the sputtering method and the plating method may be used in combination.

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

EXAMPLES (Example 1) Production of hot plate (see FIGS. 1 and 4) (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 placed in a mold and formed into a flat plate to obtain a formed product (green).

(3) The formed product 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 210 mm was cut out from the plate, and the surface was polished with a diamond paste having an average particle diameter of 1 μm, and the surface of the contact portion was Rm according to JIS R0601.
ax = 2 μm was used as a ceramic plate (ceramic substrate 41). Next, a drilling process is performed on the plate-like body, a through hole 45 for inserting a lifter pin for transporting a semiconductor wafer, and a bottomed hole for embedding a thermocouple (diameter: 1.1 mm, depth: 2 mm). 44, a recess (see FIG. 1) for inserting and fixing the support member was formed (FIG. 5).
(A)).

(4) Ceramic substrate 4 obtained in (3) above
A conductor paste was printed on the bottom surface of the substrate 1 by screen printing. The printing pattern was a concentric pattern as shown in FIG. 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 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. The silver resistance heating element 42 has a thickness of 5 μm, a width of 2.4 mm, and a sheet resistivity of 7.25 near its terminal.
It was 7 mΩ / □ (FIG. 5B).

(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 1 μm-thick metal coating layer 420 (nickel layer) on the surface of the silver resistance heating element 42 (FIG. 5C).

(7) A silver-lead solder paste (manufactured by Tanaka Kikinzoku Co., Ltd.) was printed on the end of the resistance heating element 42 by screen printing to secure a connection with a power source to form a solder layer. Then, an external terminal 43 having a T-shaped cross section was placed on the solder layer, and the terminal was heated and reflowed at 420 ° C., and the external terminal 43 was attached to the end of the resistance heating element via the solder layer 420. (8) A thermocouple for temperature control is inserted into the bottomed hole 44,
Fill the polyimide resin, cured at 190 ℃ 2 hours,
Ceramic substrate 4 having resistance heating element 42 on bottom surface 41b
1 was obtained.

(9) Thereafter, a support member made of Kovar metal spring having the shape shown in FIG.
The ceramic substrate 41 is placed in a supporting container 11 provided with R 0601 (Rmax = 0.1 μm) 12 and
9 by inserting and fixing the upper end of the support member 12
The manufacturing of the hot plate 10 was completed by supporting the ceramic substrate 41 and performing wiring work such as conductive wires.

Example 2 Hot Plate (See FIGS. 3 and 5) (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 : yttria, average particle diameter: 0.4 μm) 4 parts by weight, 11.5 parts by weight of an acrylic binder, 0.5 parts by weight of a dispersant, and a paste obtained by mixing 53 parts by weight of alcohol composed of 1-butanol and ethanol Was formed by a doctor blade method to prepare a green sheet 500 having a thickness of 0.47 mm.

(2) Next, after drying the green sheet 500 at 80 ° C. for 5 hours, a through-hole or the like serving as a through-hole 58 was formed by punching.

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

Tungsten particles 10 having an average particle diameter of 3 μm
A conductive paste B was prepared by mixing 0 parts by weight, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of an α-terpineol solvent, and 0.2 parts by weight of a dispersant. This conductor paste A was printed on a green sheet by screen printing to form a conductor paste layer 520 for the resistance heating element 52. The printing pattern was a concentric pattern as shown in FIG. 1, the width of the conductive paste layer was 10 mm, and the thickness was 12 μm.
m. In addition, a conductive paste B was filled into a portion to be a through hole to form a filling layer 580.

Green sheet 500 after the above processing
37 green sheets 500 on which no conductor paste is printed are printed on the upper side (heating surface), 13 sheets on the lower side, 130 ° C., 8
The layers were laminated at a pressure of MPa (FIG. 6A).

(4) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and at 1890 ° C. under a pressure of 15M.
Hot pressing was performed at Pa for 10 hours to obtain a 3 mm-thick aluminum nitride sintered body. This was cut out into a disk shape of 230 mm, and the surface was polished with a diamond paste having an average particle size of 1 μm, so that the surface of the contact portion was JIS R06.
01, Rmax = 2 μm, and a resistance heating element 52 having a thickness of 6 μm and a width of 10 mm (aspect ratio: 1666) inside
And a ceramic substrate 51 having a through hole 58.

(5) Next, the plate obtained in (4) is
After polishing with a diamond grindstone, a mask was placed, and a bottomed hole 54 for a thermocouple and a through hole 55 for inserting a lifter pin for carrying a silicon wafer or the like were provided on the surface by blasting with glass beads. (FIG. 6
(B)).

(6) Further, a portion immediately below the through hole 58 is cut out with a drill to have a diameter of 3.0 mm and a depth of 0.5.
A through hole 58 is formed by exposing the through hole 58 (FIG. 6 (c)).

(7) A plurality of thermocouples for temperature control are embedded in the bottomed holes 54, filled with a polyimide resin, and
Cured for 2 hours at ° C. (8) Thereafter, the support container 12 is prepared, and the support container 1
After the middle plate 15 is attached to the second plate 2, the steel plate spring (with a surface roughness of R according to JIS R 0601)
(max = 0.1 μm) 16 and the external terminal 22 are attached, and the lead wire 17 extending from the external terminal 13 is inserted into the through hole 14.
Pull out to outside via a.

(9) Thereafter, the ceramic substrate 51 is placed in the support container 11 provided with the support member 12 having the shape shown in FIG. 1, and the upper end of the support member 12 is inserted and fixed in the concave portion 59. By supporting the ceramic substrate 51 and performing wiring work of conductive wires and the like, the hot plate 2
0 has been discontinued.

Example 3 As Example 1, except that alumina having a porosity of 10% (diameter of 10 m) was used as a supporting member.
m, height 20 mm). Such an alumina support member was manufactured by molding alumina powder having a particle diameter of 1 μm into a columnar shape and sintering at 1600 ° C. for 3 hours under normal pressure. Then, after this, the end face of the column is set to an average particle diameter of 1 μm.
polished with diamond paste of m.
According to IS R0601, Rmax was set to 1 μm. The upper portion of the alumina support member is fitted into a concave portion 49 formed on the bottom surface of the ceramic substrate 41.

Example 4 The same as Example 1, except that alumina having a porosity of 10% (diameter of 10 m) was used as a supporting member.
m, height 20 mm). Such an alumina support member was manufactured by molding alumina powder having a particle diameter of 1 μm into a columnar shape and sintering at 1600 ° C. for 3 hours under normal pressure. Then, after this, the end face of the column is set to an average particle diameter of 0.
Polishing was performed with a diamond paste of 05 μm, and the surface of the contact portion was set to 0.08 μm according to JIS R0601 Rmax. The ceramic substrate is also polished with a diamond paste having an average particle diameter of 0.05 μm, and the contact surface is JIS R
0601 Rmax was set to 0.08 μm. The upper portion of the alumina support member is fitted into a concave portion 49 formed on the bottom surface of the ceramic substrate 41.

(Comparative Example 1) After a ceramic substrate 41 was manufactured in the same manner as in Example 1, it was fitted into the support container 20 shown in FIG. 7 via a heat insulating ring 25, and wiring work such as conductive wires was performed. Thus, a hot plate was manufactured.

The hot plates according to Examples 1 to 4 and Comparative Example 1 were energized and heated to 300 ° C., and the temperature of the entire heated surface was measured using a thermoviewer (IR16 manufactured by Nippon Datum Co., Ltd.).
2012-0012).

In the ceramic substrates of the products according to Examples 1 to 4, the entire heating surface was at a substantially uniform temperature.
In the hot plate according to Comparative Example 1, the ceramic substrate 4
Cooling spots were generated in portions near the outer periphery of 1, 51.

The difference between the maximum temperature and the minimum temperature (ΔT ° C.) of the heated surface was measured using this thermoviewer. In Example 1, ΔT was 5 ° C., and in Example 2, ΔT was 6 ° C.
° C, ΔT is 6 ° C in Example 3, and ΔT is 8 ° C in Example 4.
In Comparative Example 1, ΔT was 12 ° C.
And it was getting bigger. Further, in comparison of Examples 3 and 4,
Example 4 has a slightly larger ΔT. It is presumed that the contact area is large because the support member and the ceramic substrate themselves are almost mirror surfaces.

[0123]

As described above, in the hot plate according to the present invention, the side surface and the outer peripheral portion of the bottom surface of the ceramic substrate are not in contact with the heat insulating ring, the supporting container, or the like at all, and the air is the same as the other portions. , Heat dissipation from this portion does not become larger than in other portions, and a cooling spot does not occur in these portions.

Further, since the contact portion between the support member and the ceramic substrate exists inside the area where the resistance heating element is formed, the amount of heat generated from the support member is controlled by controlling the amount of heat generated by the resistance heating element. Heat dissipation can be supplemented, and the generation of a cooling spot on the ceramic substrate can be prevented. Therefore, the temperature of the heating surface of the ceramic substrate can be made uniform, and an object to be heated such as a silicon wafer can be uniformly heated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a hot plate of the present invention.

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

FIG. 3 is a cross-sectional view schematically showing another example of the hot plate of the present invention.

FIG. 4 is a sectional view schematically showing still another example of the hot plate of the present invention.

5 (a) to 5 (d) are cross-sectional views schematically showing a part of the manufacturing process of the ceramic substrate constituting the hot plate shown in FIG. 1 of the present invention.

FIGS. 6A to 6D are cross-sectional views schematically showing a part of a manufacturing process of a ceramic substrate constituting the hot plate shown in FIG. 3 of the present invention.

FIG. 7 is a cross-sectional view schematically illustrating an example of a conventional hot plate.

[Explanation of symbols]

 10, 50 Hot plate 11 Support container 11a Through hole 12 Support member 18 Fixture 23 Socket 41, 51 Ceramic substrate 42, 52 Resistance heating element 43, 53 External terminal 44, 54 Bottom hole 45, 55 Through hole 46, 56 Wiring 47, 57 Temperature measuring element 49, 59 Concave part 58 Through hole

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 29, 2001 (2001.5.2)
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

[Title of the Invention] Hot plate for semiconductor manufacturing and inspection equipment

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 3K034 AA10 AA21 AA34 AA37 BB06 BC04 BC12 CA02 CA14 CA26 DA04 3K092 PP09 QA05 QB02 QB03 QB44 QB74 QC25 QC52 RF03 RF11 RF22 TT22 UA05 VV22 4M106 AA03 HA03 HA02 HA02 HA38 HA50 JA01 JA46

Claims (6)

[Claims] 1. A hot plate in which a ceramic substrate having a resistance heating element formed on the surface or inside thereof is disposed in a support container, wherein the ceramic substrate is a support plate installed in the support container. A hot plate, wherein the hot plate is supported by a member, and a contact portion between the support member and the ceramic substrate exists inside a region where the resistance heating element is formed. 2. The hot plate according to claim 1, wherein the support member is made of an elastic body. 3. The hot plate according to claim 2, wherein the elastic body is a metal spring. 4. The hot plate according to claim 1, wherein said support member is made of ceramic. 5. The hot plate according to claim 4, wherein said support member is made of alumina. 6. The surface of the contact portion between the support member and the ceramic substrate has an Rmax of 0.1 μm according to JIS R0601.
The hot plate according to any one of claims 1 to 5, which is as described above.