JP2002246160A - Hot plate unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot plate unit, capable of securing flatness for the heating surface of a ceramic heater and uniformly heating a semiconductor wafer as a heated object, by adjusting a deflection quantity of a ceramic board. SOLUTION: The hot plate unit includes the ceramic board with a resistance heating element formed on a surface or inside of the ceramic board and a support container of a bottomed cylinder shape for supporting the ceramic board, and is characterized by that a reflection quantity adjusting means for adjusting the deflection quantity of the ceramic board is provided with the support container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot plate unit used mainly for drying, sputtering and the like in the semiconductor industry, and a hot plate unit used as a hot plate, an electrostatic chuck, a wafer prober and the like. , A hot plate unit for semiconductor manufacturing and inspection.

[0002]

2. Description of the Related Art Semiconductor products are manufactured through a process of forming a photosensitive resin on a semiconductor wafer as an etching resist and etching the semiconductor wafer. This photosensitive resin is a liquid and is applied to the surface of the semiconductor wafer using a spin coater or the like.However, it must be dried after application, and the applied semiconductor wafer is placed on a heater and heated. become.

Conventionally, as a heater for heating such a silicon wafer, a heater provided with a resistance heating element such as an electric resistor on the back side of an aluminum substrate has been frequently used. A thickness of about 15 mm is required, which increases the weight and is bulky, making it difficult to handle. Further, the temperature controllability is insufficient from the viewpoint of the temperature followability with respect to the flowing current, and the silicon wafer is heated uniformly. It was not easy.

Therefore, recently, a ceramic heater using a ceramic such as aluminum nitride as a substrate has been developed. These heaters are excellent in mechanical properties such as bending strength, so that the thickness can be reduced, and the heat capacity can be reduced, so that the heaters are excellent in various properties such as temperature followability.

Usually, such a ceramic heater has a disk shape and is mounted on a supporting container having a bottomed cylindrical shape having substantially the same diameter as the ceramic substrate, and is used as a hot plate unit. In addition, the supporting container supports the ceramic heater, and the wiring is stored in the inside, and also shields the radiant heat from the ceramic heater,
It serves to protect a surrounding power supply and / or a control device or the like in which precision equipment is housed.

[0006]

By the way, in the recent manufacture of semiconductor products, a large-diameter ceramic heater capable of mounting a large-diameter semiconductor wafer has been required as the diameter of the semiconductor wafer has increased. I have. However, in the ceramic heater (hot plate unit) having the above-described configuration, the thickness of the ceramic substrate is reduced and the heat capacity is reduced so as to have excellent temperature followability and the like. , 2
In a middle temperature range of 00 to 400 ° C. or a high temperature range of 400 to 800 ° C., the ceramic substrate bends, and the distance between the heating surface of the ceramic heater and the semiconductor wafer to be heated varies depending on the location. As a result, there is a problem that it becomes difficult to uniformly heat the semiconductor wafer.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the flatness of a heating surface of a ceramic heater is ensured by adjusting the amount of deflection of a ceramic substrate. It is an object of the present invention to provide a hot plate unit that can uniformly heat a semiconductor wafer to be heated.

That is, the hot plate unit of the present invention is a hot plate unit including a ceramic substrate having a resistance heating element formed on the surface or inside thereof, and a bottomed cylindrical support container for supporting the ceramic substrate. Further, the hot plate unit is characterized in that the support container is provided with a bending adjusting means for adjusting a bending amount of the ceramic substrate.

According to the present invention, since the supporting container is provided with the bending adjusting means for adjusting the amount of bending of the ceramic substrate, the amount of bending of the ceramic substrate is adjusted using the bending adjusting means. Thereby, the flatness of the heating surface of the ceramic heater can be ensured, and the semiconductor wafer to be heated can be uniformly heated.

[0010] In the hot plate unit of the present invention, the deflection adjusting means may be provided at the bottom of the support container.
It is desirable that a screw hole be formed and a deflection adjusting screw be disposed in the screw hole. In the supporting container, the amount of deflection of the ceramic substrate can be accurately adjusted by adjusting the tightening of the deflection adjusting screw provided in the screw hole at the bottom thereof and pushing up the ceramic substrate from the bottom surface. Because you can. In addition,
The configuration of such a flexure adjusting means is not complicated, so that the productivity of the hot plate unit is not reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hot plate unit according to the present invention comprises a ceramic substrate having a resistance heating element formed on the surface or inside thereof, and a bottomed cylindrical support container for supporting the ceramic substrate. A hot plate unit, wherein the support container is provided with a bending adjusting means for adjusting a bending amount of the ceramic substrate.

FIG. 1A is a sectional view schematically showing a hot plate unit of the present invention, and FIG. 1B is a partially enlarged sectional view thereof. FIG. 2 is a plan view schematically showing a ceramic substrate constituting the hot plate unit of FIG. 1, and FIG. 3 is a perspective view of a container constituting the hot plate unit as viewed from above.

The hot plate unit 100 is in contact with the ceramic substrate 1a in a non-contact manner only through a disk-shaped ceramic substrate 1a in which a resistance heating element 2 is formed and a bolt 18 provided on the bottom surface thereof. It is configured to include a cylindrical support container 10 with a bottom that supports in a state.
As shown in FIG. 2, a resistance heating element 2 composed of a plurality of circuits is embedded in the ceramic substrate 1a.
A bottomed hole 4 and a through hole 5 are formed. In the through hole 5,
By inserting lifter pins (not shown), the semiconductor wafer 29 to be heated can be supported, and by moving the lifter pins up and down, delivery and the like of the semiconductor wafer 29 can be performed. It is possible.
In the bottomed hole 4, a temperature measuring element 3 to which a lead wire 19 is connected for measuring the temperature of the ceramic substrate 1a is embedded. Note that, as described above, the ceramic substrate in which the resistance heating element is formed inside or on the surface and in which the bottomed hole and the through hole are formed is also referred to as a ceramic heater in the following description.

A resistance heating element 2 is formed inside a disk-shaped ceramic substrate 1a constituting the ceramic heater 1. Then, the resistance heating element 2 is, as shown in FIG.
On the outermost periphery of the ceramic substrate 1a, resistance heating elements 2a to 2d, which are arc patterns repeatedly formed so as to draw a part of a concentric circle, are arranged. Heating elements 2e to 2g are arranged.

The outermost resistance heating element 2a is formed by repeating a circular arc-shaped pattern obtained by dividing a concentric circle into four in the circumferential direction, and ends of adjacent arcs are connected by a bent line to form a series of circuits. ing. Then, four circuits of the resistance heating elements 2a to 2d having the same pattern are formed close to each other so as to surround the outer periphery, and constitute an overall annular pattern.

The ends of the resistance heating elements 2a to 2d are formed inside an annular pattern in order to prevent the occurrence of a cooling spot or the like. It is extended toward.

Resistance heating elements 2a to 2d formed on the outermost periphery
Inside, are formed resistance heating elements 2e to 2g each formed of a circuit of a concentric pattern whose part is cut off. In the resistance heating elements 2e to 2g, a series of circuits is configured by connecting the ends of adjacent concentric circles sequentially with resistance heating elements formed of straight lines.

The resistance heating elements 2a to 2d, 2e, 2
Between f and 2g, a band-shaped (annular) non-heating element non-forming area is provided, and a circular heating element non-forming area is also provided at the center.

Accordingly, as a whole, annular resistance heating element forming areas and heating element non-forming areas are alternately formed from the outside to the inside, and these areas are defined by the size (diameter) of the ceramic substrate. ), Thickness, etc., the temperature can be made uniform by setting the temperature appropriately.

The above-described resistance heating element 2 is a ceramic substrate 1
a, a blind hole 7 is formed immediately below the portion where the end of the circuit exists, and a washer 9 serving as a conductive buffer is fitted into the blind hole 7 and the The lead wire 19 is inserted into the center hole, and the washer 9 and the lead wire 19 are brazed so that the end of the resistance heating element 2 and the lead wire 19 are connected through the through hole 8. In addition, the washer 9
Due to the difference in the coefficient of thermal expansion between the lead wire 19 and the ceramic substrate 1a, in order to prevent cracks that occur when the material forming the lead wire 19 is directly embedded in the ceramic substrate,
It is installed as a cushioning material and has a coefficient of thermal expansion intermediate between the two.

Further, a plurality of recesses 6a are formed in the heating surface of the ceramic heater 1, and support pins 6 are provided in the recesses 6a. It can be supported and heated in a state of being separated from the heating surface by a certain distance. In the hot plate unit 100 of the present invention, the recess 6a and the support pin 6 may or may not be provided. It is also possible to support and heat the semiconductor wafer 29 at a certain distance from the heating surface of the ceramic heater 1 using lifter pins (not shown) inserted through the through holes 5 instead of the support pins 6. It is.

Further, as shown in FIG.
Has a cylindrical outer frame portion 17 and a disc-shaped bottom portion 12,
It is formed integrally, and the middle bottom part 11 is attached in the middle of the outer frame part 17. The bottom portion 12 is provided for the purpose of heat shielding and the like, and a coolant introduction pipe 16 is attached to the bottom portion 12 so that a coolant or the like for forced cooling can be introduced into the support container 10. And a through hole 12a for discharging the introduced forced cooling refrigerant or the like is formed. Further, as shown in FIG.
A cross-shaped reinforcing member 28 is provided for the purpose of preventing the bending of the reinforcing member. The reinforcing member 28 is provided at the bottom 1
2 may be provided integrally, or may be provided on the lower surface of the bottom portion 12.

The midsole plate 11 is provided for the purpose of fixing wiring and the like, heat shielding, and the like. The midsole plate 11 has a refrigerant introduction pipe 16 fixed to the bottom 12 and a lifter pin (not shown). ), A bending adjusting screw 20 for adjusting the amount of bending of the ceramic substrate 1a, and the like, and a through hole is formed in a portion that does not interfere with these. In the present invention,
The midsole plate 11 is not essential. That is, even if the midsole plate 11 is not formed in the support container 10, it functions as the hot plate unit of the present invention.

A through hole is formed in a portion near the outer peripheral edge of the ceramic heater 1, and a bolt 1 is formed in the through hole.
8 is inserted, and an end of the bolt 18 is fixed to the support container bottom 12. Therefore, the ceramic heater 1 is supported by the support container 10 (outer frame) via the bolt 18 erected on the support container bottom 12. Inside the part 17), the support container 1
It is supported and fixed in a non-contact state with 0.
Further, the ceramic heater 1 and the bottom 12
It is supported and fixed so as to be substantially parallel to. further,
In this state, the side surface of the ceramic heater 1 and the inner side surface of the outer frame portion are slightly separated from each other so as not to be in contact with each other, and the air plays a role as a heat insulating material. Difficult to escape.

In the hot plate unit 100 of the present invention, a screw hole 21 is formed in the bottom portion 12 of the support container 10 as the above-mentioned deflection adjusting means, and the tip of the screw hole 21 has a conical deflection adjustment. Screw 20 is provided. Accordingly, by adjusting the tightening of the deflection adjusting screw 20 and pushing up the ceramic substrate 1a from the bottom surface, the amount of deflection of the ceramic substrate 1a can be adjusted with high accuracy. As a result, the flatness of the heating surface of the ceramic heater 1 can be ensured, and the semiconductor wafer 29 to be heated can be uniformly heated. In addition, since the tip of the deflection adjusting screw 20 has a conical shape, the heat of the ceramic heater 1 does not easily dissipate, and the occurrence of a singular point such as a cooling spot can be prevented.
Note that the deflection adjusting means does not necessarily need to use the deflection adjusting screw 20, and is not particularly limited as long as it can adjust the amount of deflection of the ceramic substrate.

The hot plate unit 100 includes:
A control device (not shown) containing a control device, a power supply, and the like is provided below the hot plate unit. The lead wire 19 is connected to a control device, a power supply, and the like in the control device and is energized. Function as

In the hot plate unit shown in FIGS.
Although the resistance heating element 2 is embedded inside the ceramic substrate 1a, in the hot plate unit of the present invention, the resistance heating element may be formed on the surface of the ceramic substrate.

FIG. 4 is a cross-sectional view schematically showing another embodiment of the hot plate unit of the present invention, and FIG.
FIG. 5 is a plan view schematically illustrating a ceramic substrate constituting the hot plate unit in FIG. 4.

The hot plate unit 500 includes a ceramic substrate 51a having a surface (bottom surface) on which a resistance heating element 52 is formed, and a bottomed cylindrical support container 60 for supporting the ceramic substrate 51a. As shown in FIG. 5, on the surface (bottom surface) of the disc-shaped ceramic substrate 51a, a resistance heating element 52 including a plurality of circuits is formed, and a bottomed hole 54 and a through hole 55 are formed. . Also, like the hot plate unit 100,
By inserting lifter pins (not shown) into the through-holes 55, the semiconductor wafer 29 as an object to be heated can be held. Delivery of the wafer 29 or the like is possible. In the bottomed hole 54, the ceramic substrate 51 is provided.
A temperature measuring element 53 connected to a lead wire 69 for measuring the temperature of a is embedded.

A resistance heating element 52 is formed on the surface (bottom surface) of a disk-shaped ceramic substrate 51a constituting the ceramic heater 51. And the resistance heating element 52
As shown in FIG. 5, the ceramic substrate 51a
Resistance heating elements 52a to 52a which are repetitive patterns of bent lines
2d, and the resistance heating elements 52a-5
Resistance heating elements 52e to 52h and 52i to 52l, which are a repetitive pattern of bent lines having the same shape as 2d, are arranged.

A metal coating layer (not shown) is formed on the surface of the resistance heating element 52 to prevent oxidation or the like of the resistance heating element, and an external terminal 63 is provided at an end of the resistance heating element 52. The external terminal 63 has a socket 6
4 is connected to the lead wire 69 (see FIG. 4).

Further, on the heating surface of the ceramic heater 51, a plurality of concave portions 56a are formed, and the concave portions 56a are formed.
A is provided with support pins 56 so that the semiconductor wafer 29 as an object to be heated can be supported and heated with a certain distance from the heating surface of the ceramic heater 51. In the hot plate unit 500 of the present invention, the recess 56a and the support pin 5
6 is similar to the hot plate unit 100,
It may be provided or may not be provided. The semiconductor wafer 29 is not held by the support pins 56 but by lifter pins (not shown) inserted through the through holes 55.
It is also possible to support and heat the ceramic heater 51 while keeping it at a certain distance from the heating surface.

As with the hot plate unit 100 shown in FIG. 1, a through hole is formed in a portion near the outer peripheral edge of the ceramic heater 51, and a bolt 68 is inserted into the through hole and the bolt 68 Is fixed to the support container bottom 62. Therefore, the ceramic heater 51 is supported and fixed inside the support container 60 (outer frame 67) via the bolt 68 provided upright on the support container bottom 62. Have been. In this state, the side surface of the ceramic heater 51 and the inner surface of the outer frame portion are slightly separated from each other so as not to be in contact with each other, and the air plays a role as a heat insulating material. It is difficult for heat to escape.
The support container 60 has the same configuration as the support container 10 shown in FIG.

In the hot plate unit 500 of the present invention, the bending adjusting screw 30 is used as the bending adjusting means. That is, the screw hole 31 is formed in the bottom 62 of the support container 60, and the screw hole 31 is formed in the screw hole 31.
A bending adjustment screw 30 having a semi-spherical tip is provided. By adjusting the tightening of the bending adjustment screw 30 and pushing up the ceramic substrate 51a from the bottom surface, the amount of bending of the ceramic substrate 51a can be precisely controlled. Can be adjusted well. As a result, the flatness of the heating surface of the ceramic heater 51 can be ensured, and the semiconductor wafer 29 to be heated can be uniformly heated. Further, since the tip of the deflection adjusting screw 30 has a hemispherical shape, the heat of the ceramic heater 51 does not easily dissipate, and the occurrence of a singular point such as a cooling spot can be prevented. In addition,
The screw hole 31 is formed so that the deflection adjusting screw 30 does not contact the resistance heating element 52 formed on the bottom surface of the ceramic heater 51.

The deflection adjusting means does not necessarily need to be a means using the deflection adjusting screw 30, and is not particularly limited as long as it can adjust the amount of deflection of the ceramic substrate.

The hot plate unit 500 includes:
A control device (not shown) containing a control device, a power supply, and the like is provided below the hot plate unit. The lead wire 69 is connected to a control device, a power supply, and the like in the control device and is energized. Function as

In the hot plate unit of the present invention, examples of the bending adjusting means provided on the supporting container include the above-mentioned bending adjusting screw, a pin,
Springs, jacks, and the like are included. When a pin or a spring is used as the deflection adjusting means, a pin and / or a spring is inserted between the bottom of the support container and the ceramic substrate,
By adjusting the amount of deflection of the ceramic substrate by pushing up the ceramic substrate from the bottom with pins and / or springs,
When a jack is used as the deflection adjusting means, a jack is provided between the bottom of the support container and the ceramic substrate, and the jack is used to push up the ceramic substrate from the bottom surface to adjust the amount of deflection of the ceramic substrate.

It is also possible to use a jack having a hydraulic press mechanism such as hydraulic or pneumatic as the jack. Further, the hot plate unit is provided with a means for measuring the amount of deflection of the ceramic substrate, such as a displacement meter, and by connecting the deflection adjusting screw or the jack to a servomotor or the like, the amount of deflection of the ceramic substrate can be accurately determined. Can also be controlled.

As a method of adjusting the amount of deflection of the ceramic substrate, a screw hole is formed in the bottom of the above-described support container, a screw for adjusting deflection is provided in the screw hole, and the tightening of the screw for adjusting deflection is adjusted. By doing so, it is preferable to push up the ceramic substrate from the bottom surface and adjust the amount of bending of the ceramic substrate. By adjusting the tightening of the deflection adjusting screw and pushing up the ceramic substrate from the bottom surface, the amount of deflection of the ceramic substrate can be adjusted accurately, and such a deflection adjusting means has a complicated structure. This is because the productivity of the hot plate unit does not decrease.

Accordingly, in the following description, a description will be given of a hot plate unit provided with the above-described deflection adjusting screw as the deflection adjusting means, but the deflection adjusting screw uses the deflection adjusting screw. It is not limited to the means.

In the hot plate unit of the present invention, the number of the deflection adjusting screws provided is not particularly limited, but it does not decrease the productivity of the hot plate unit and increases the heating surface of the ceramic heater. From the viewpoint of ensuring flatness, when the diameter of the ceramic substrate is 200 mm or more, it is preferable that the number is 1 to 7.

Further, it is desirable that the deflection adjusting screws are widely distributed at the bottom of the support container and are arranged at equal intervals. By arranging the deflection adjusting screw in such a form, it becomes possible to accurately adjust the deflection of the ceramic substrate depending on the location, so that the flatness of the heating surface of the ceramic heater can be ensured, It is possible to uniformly heat the semiconductor wafer to be heated. On the other hand, when the deflection adjusting screws are unevenly distributed on the bottom of the support container and / or are provided at irregular intervals, a place where the interval between the deflection adjusting screws is wide is formed, and at that location, the ceramic substrate is formed. Since bending occurs,
The flatness of the heating surface of the ceramic heater cannot be ensured, and it becomes difficult to uniformly heat the semiconductor wafer to be heated.

With regard to the arrangement of the above-mentioned deflection adjusting screws, for example, a plurality of deflection adjusting screws which are in contact with the ceramic substrate at equal intervals are provided on the relatively outer peripheral portion of the ceramic substrate and on the circumference of a concentric circle with the ceramic substrate. An arrangement in which one deflection adjusting screw is provided in contact with the center of the ceramic substrate may be used.

In the case of a hot plate unit including a ceramic substrate having a resistance heating element formed on its surface (bottom surface), a supporting container is provided so that the deflection adjusting screw does not contact the resistance heating element. A screw for adjusting the deflection is arranged at the bottom of the. Further, in order to prevent heat from escaping from the resistance heating element through the deflection adjustment screw, it is desirable to dispose the deflection adjustment screw as far as possible from the resistance heating element.

The tip of the deflection adjusting screw is, for example,
It is desirable that the shape be a conical shape as shown in FIG. 1 or a semi-spherical shape as shown in FIG. This is because it is possible to prevent a singular point such as a cooling spot from being generated on the heating surface of the ceramic heater.

The material used for the deflection adjusting screw is not particularly limited, but a material having excellent strength at a high temperature so that the ceramic substrate can be pushed up and the amount of deflection can be adjusted. It is desirable to use. Also, at high temperatures, at the bottom of the support vessel,
It is desirable to use a screw having a low coefficient of thermal expansion so that cracks and the like due to expansion of the deflection adjusting screw do not occur. Furthermore, in order to prevent the ceramic heater from exhibiting excellent temperature followability at the time of temperature rise and to prevent a singular point such as a cooling spot from being generated on the heating surface of the ceramic heater, it is desirable to use a material having a low thermal conductivity. . Examples of such a material include a resin, a ceramic, and a metal. Among these, the resin and the ceramic are preferable.

Examples of the resin include PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy fluororesin), epoxy resin and the like.
Examples of the ceramic include alumina, mullite, quartz, and the like.

The above-described deflection adjusting screw is provided in a screw hole formed at the bottom of the support container. As shown in FIG. 1, the support container 10 has a cylindrical shape with a bottom, and a cylindrical outer frame portion 17 and a disk-shaped bottom portion 12 are integrally formed. The midsole plate 11 is attached in the middle of the figure.

The bottom is desirably disc-shaped, and the thickness of the bottom is desirably 0.1 mm or more. If it is less than 0.1 mm, the bottom is too thin,
Since it is difficult to form a screw hole and the strength becomes poor, the bending adjustment screw provided on the bottom part
When pushed up from the bottom of the ceramic substrate, the bottom is bent,
It may be difficult to adjust the deflection of the ceramic substrate. When the bottom is thin, it is desirable to provide a reinforcing member on the bottom in order to suppress the occurrence of bending, and when such a reinforcing member is provided, the thickness of the bottom is 0.1 mm. It may be less than 1 mm. For example, as shown in FIG. 3, the reinforcing member can be formed on the upper surface of the bottom portion so as to have a cross shape inside the outer frame portion.

Further, as shown in FIG. 1, the outer frame portion and the bottom portion may be integrated, or the bottom portion may be connected and fixed to the outer frame portion. It is desirable that the outer frame portion and the bottom portion are integrated so as to prevent the bottom portion from being bent when being pushed up from the bottom surface of the ceramic substrate by the deflection adjusting screw provided on the bottom portion.

The outer frame portion and the bottom portion are easy to process and have excellent mechanical properties, secure the strength of the entire support container, and are pushed up from the bottom surface of the ceramic substrate by the deflection adjusting screws provided at the bottom portion. At this time, it is preferable that the supporting container is made of a metal such as SUS, aluminum, and inconel (a nickel-based alloy containing 16% of chromium and 7% of iron) so as not to bend the supporting container. When the outer frame portion and the bottom portion are not integrated, the bottom portion is blended with, for example, a heat-resistant resin, a ceramic plate, and a heat-resistant organic fiber or an inorganic fiber so as to have excellent heat shielding properties. It is also possible to use a composite plate or the like that does not have a large thermal conductivity and is excellent in heat resistance.

A member that can be fixed may be installed in the through hole provided at the bottom so that the lead wire or the like does not move while being inserted. Etc. may be inserted.

Further, it is desirable that a refrigerant introduction pipe is attached to the bottom. This is because a forced cooling refrigerant or the like for cooling the ceramic heater can be efficiently introduced into the support container. Further, it is desirable that a through hole for discharging the introduced forced cooling refrigerant or the like be formed at the bottom.

The midsole plate is provided for the purpose of fixing wiring and the like and for heat shielding. However, in the hot plate unit of the present invention, the midsole plate may be provided in the support container, and is not provided. You may. Further, as shown in FIG. 1, the middle bottom plate 11 includes a refrigerant introduction pipe 16 fixed to the bottom 12, a guide pipe 15 for protecting a lifter pin (not shown), and a deflection adjusting screw 20. A through hole is formed so as not to obstruct.

The deflection adjusting screw provided at the bottom of the above-described support container functions as a deflection adjusting means by operating as follows. That is, as shown in FIG. 1, a screw hole 21 having a thread groove is provided in the bottom portion 12,
A screw 20 for bending adjustment is provided in the screw hole 21, and the screw 20 for bending adjustment can be moved up and down by rotating the screw 20 for bending adjustment.
The upper end of the deflection adjusting screw 20 is connected to the ceramic substrate 1a.
Is in contact with Therefore, by rotating the bending adjustment screw 20, the ceramic substrate 1a is pushed up from the bottom surface, the amount of bending of the ceramic substrate 1a is adjusted, and the flatness of the heating surface of the ceramic heater 1 can be ensured. The semiconductor wafer 29 as an object can be uniformly heated.

The adjustment of the amount of deflection of the ceramic substrate as described above may be performed when the temperature of the hot plate unit is raised, or may be performed when the temperature is not raised. In addition, a temperature rise test is performed on the ceramic substrate in advance, and the relationship between the material, thickness, diameter, etc. of the ceramic substrate, the amount of deflection, and the temperature is obtained, and the flatness of the heating surface of the ceramic heater is ensured during the temperature rise. Before the temperature rise, the tightening of the deflection adjusting screw may be adjusted so that the temperature can be increased.

Further, the operating temperature range of the hot plate unit of the present invention having the above-described deflection adjusting means is as follows.
There is no particular limitation, and a low temperature range of 100 to 200 ° C., 200
It can be used in each of a medium temperature region of 400 to 800C and a high temperature region of 400 to 800C. Above all, 200-4
It is desirable to use it in each of a middle temperature range of 00 ° C. and a high temperature range of 400 to 800 ° C. This is because the rigidity of the ceramic substrate is reduced at a high temperature, and the ceramic substrate is likely to be bent due to its own weight or the like, so that the configuration of the present invention functions effectively.

Next, the ceramic heater constituting the hot plate unit of the present invention will be described in more detail.

The ceramic substrate used for the ceramic heater has a disk shape and a diameter of 200 mm.
mm is desirable. This is because a substrate having such a large diameter is capable of mounting a semiconductor wafer having a large diameter, and a ceramic substrate having a large diameter is liable to be bent, and the configuration of the present invention functions effectively. It is. The diameter of the ceramic substrate is particularly preferably 12 inches (300 mm) or more. This is because it will become the mainstream of next-generation semiconductor wafers.

The thickness of the ceramic substrate is 25
mm or less. This is because if the thickness of the ceramic substrate exceeds 25 mm, the temperature followability decreases. Further, its thickness is desirably 0.5 mm or more. When the thickness is smaller than 0.5 mm, the strength of the ceramic substrate itself is reduced, so that the ceramic substrate is easily broken. More preferably, it is more than 1.5 and 5 mm or less. If the thickness is more than 5 mm, the heat is difficult to propagate, and the heating efficiency tends to decrease. May occur, and the strength of the ceramic substrate may be reduced to cause breakage.

In the ceramic heater constituting the hot plate unit of the present invention, as shown in FIG. 1A, the ceramic substrate has a surface facing the heating surface from the side opposite to the heating surface on which the object to be heated is placed. It is preferable that the bottomed hole 4 is provided, the bottom of the bottomed hole 4 is formed closer to the heating surface than the resistance heating element 2, and the temperature measuring element 3 such as a thermocouple is provided in the bottomed hole 4. Further, the distance between the bottom of the bottomed hole 4 and the heating surface of the ceramic heater 1 is preferably 0.1 mm to 1/2 of the thickness of the ceramic substrate. As a result, the temperature measurement location is closer to the heating surface of the ceramic heater 1 than the resistance heating element 2, and the temperature of the semiconductor wafer can be measured more accurately.

If the distance between the bottom of the bottomed hole 4 and the heating surface of the ceramic heater 1 is less than 0.1 mm, heat will be radiated, and a temperature distribution will be formed on the heating surface of the ceramic heater 1 and the thickness will be １ ／. If the temperature exceeds the limit, the temperature of the resistance heating element becomes liable to be affected, and the temperature cannot be controlled, and a temperature distribution is formed on the heating surface of the ceramic heater 1.

The diameter of the bottomed hole 4 is desirably 0.3 mm to 5 mm. This is because if it is too large, the heat radiation will be large, and if it is too small, the workability will be reduced and the distance to the heating surface of the ceramic heater 1 cannot be equalized.

As shown in FIG. 2, it is desirable that a plurality of the bottomed holes 4 are arranged symmetrically with respect to the center of the ceramic substrate 1a and form a cross. This is because the temperature of the entire heating surface can be measured.

As the temperature measuring element, for example, a thermocouple,
Platinum resistance thermometers, thermistors and the like can be mentioned. As the thermocouple, for example, JIS-C-1602 (1
980), K type, R type, B type, S type
Type, E-type, J-type, and T-type thermocouples, and among them, a K-type thermocouple is preferable.

It is desirable that the size of the junction of the thermocouple is equal to or larger than the diameter of the strand, and is 0.5 mm or less. This is because, if the junction is large, the heat capacity increases and the responsiveness decreases. It is difficult to make the diameter smaller than the diameter of the strand.

The above temperature measuring element may be adhered to the bottom of the bottomed hole 4 using gold brazing, silver brazing or the like. Or both may be used in combination. Examples of the heat-resistant resin include a thermosetting resin, particularly an epoxy resin, a polyimide resin, a bismaleimide-triazine resin, and the like. These resins may be used alone or in combination of two or more.

As the above-mentioned gold brazing filler, 37-80.5% by weight of Au-63-19.5% by weight of Cu alloy, 81.5-8% by weight
2.5% by weight: Au-18.5 to 17.5% by weight: Ni
At least one selected from alloys is desirable. These are because the melting temperature is 900 ° C. or higher and it is difficult to melt even in a high temperature region. As a silver solder, for example, Ag
-A Cu-based material can be used.

Further, a semiconductor wafer or the like to be heated is
Since the semiconductor wafer is held at a fixed distance from the heating surface of the ceramic heater so as not to cause temperature variations due to the influence of the temperature distribution on the heating surface of the ceramic heater, as shown in FIG. It is desirable to form the support pins 6 for supporting the semiconductor wafer 29 and the concave portions 6 a for providing the support pins 6. It is also possible to form a through-hole instead of the concave portion and insert and fix the support pin.

The height at which the support pins project from the heating surface of the ceramic heater is 5 to 5000 μm, that is, the object to be heated is 5 to 5 μm from the heating surface of the ceramic substrate.
It is desirable to hold them in a state of being separated by 000 μm. 5
If it is less than μm, the temperature of the semiconductor wafer becomes non-uniform under the influence of the temperature distribution of the ceramic substrate, and if it exceeds 5000 μm, the temperature of the semiconductor wafer becomes difficult to rise, and especially, the temperature of the outer peripheral portion of the semiconductor wafer becomes low. It is because it becomes. The object to be heated and the heating surface of the ceramic substrate are 5
It is more preferable that the distance is about 500 μm.
It is more desirable to be separated by 0 μm.

In the hot plate unit of the present invention, the ceramic forming the ceramic heater is preferably a nitride ceramic or a carbide ceramic. Nitride ceramics and carbide ceramics have a lower coefficient of thermal expansion than metals and have much higher mechanical strength than metals, so even if the thickness of the ceramic substrate is reduced, it does not warp or warp due to heating . Therefore, the ceramic substrate can be made thin and light. Further, since the thermal conductivity of the ceramic substrate is high and the ceramic substrate itself is thin, the surface temperature of the ceramic substrate quickly follows the temperature change of the resistance heating element. That is, the surface temperature of the ceramic substrate can be controlled by changing the voltage and the current value to change the temperature of the resistance heating element.

As the above-mentioned nitride ceramic, for example,
Examples include aluminum nitride, silicon nitride, boron nitride, and titanium nitride. These may be used alone or 2
More than one species may be used in combination.

Examples of the carbide ceramic include silicon carbide, zirconium carbide, titanium carbide, tantalum carbide, and tungsten carbide. These may be used alone or in combination of two or more.

Of these, aluminum nitride is most preferred. The highest thermal conductivity is 180W / m · K,
This is because it has excellent temperature followability.

When a nitride ceramic or a carbide ceramic is used as the ceramic substrate, an insulating layer may be formed as necessary. Nitride ceramics have a tendency to decrease in volume resistance at high temperatures due to oxygen solid solution, etc.Carbide ceramics have conductivity unless particularly highly purified. This is because, even if it contains, a short circuit between circuits can be prevented and the temperature controllability can be secured. Further, the ceramic substrate may contain a sintering aid. Examples of the sintering aid include alkali metal oxides, alkaline earth metal oxides, and rare earth oxides. Among these sintering _{aids, CaO, Y 2 O 3,} Na 2 O, Li
₂ O and Rb ₂ O are preferred. As their content,
0.1-20% by weight is preferred. Further, it may contain alumina. The porosity of the ceramic substrate is 0.
Or 5% or less is preferable. This is because mechanical strength is high and insulation properties are excellent.

The insulating layer is preferably made of an oxide ceramic, specifically, silica, alumina, mullite,
Cordierite, beryllia and the like can be used.
Such an insulating layer may be formed by spin-coating a sol solution obtained by hydrolyzing and polymerizing an alkoxide on a ceramic substrate, followed by drying and firing, or by sputtering, CVD, or the like. Further, an oxide layer may be provided by oxidizing the surface of the ceramic substrate.

The thickness of the insulating layer is preferably 0.1 to 1000 μm. If the thickness is less than 0.1 μm, the insulating property cannot be secured, and if the thickness exceeds 1000 μm, the thermal conductivity from the resistance heating element to the ceramic substrate is hindered.
Further, it is desirable that the volume resistivity of the insulating layer is 10 times or more (same measurement temperature) as the volume resistivity of the ceramic substrate. If it is less than 10 times, a short circuit cannot be prevented.

Further, in the hot plate unit of the present invention, the ceramic substrate used for the ceramic heater contains carbon, and its content is 200 to 500.
Desirably, it is 0 ppm. This is because the electrode can be concealed and black body radiation can be easily used.

The above ceramic substrate has a brightness of JI.
It is desirable that the value based on the definition of SZ8721 be N6 or less. This is because a material having such a lightness is excellent in radiant heat and concealing property. Where the lightness N
Sets the ideal black lightness to 0 and the ideal white lightness to 1
0, each color is divided into 10 between these black lightness and white lightness so that the perception of the brightness of the color becomes the same rate, and displayed by symbols N0 to N10. The actual measurement is performed by comparing the color charts corresponding to N0 to N10. In this case, the first decimal place is 0 or 5.

In the present invention, if the resistance heating element formed on the ceramic heater is divided into a plurality of circuits,
The pattern is not particularly limited. For example, a pattern using a combination of a circular arc repetition pattern and a concentric pattern shown in FIG. 2, a repetition pattern of a bent line shown in FIG. pattern,
An eccentric pattern, a concentric pattern, and the like can be given. Further, these patterns may be formed alone, or may be formed by arbitrarily combining these patterns.

It is preferable that the resistance heating element is divided into at least two or more circuits. This is because, by dividing the circuit, the amount of heat generated can be changed by controlling the power supplied to each circuit, and the temperature of the heating surface of the semiconductor wafer can be adjusted.

The thickness of the resistance heating element is preferably 1 to 30 μm, more preferably 1 to 10 μm. Further, the width of the resistance heating element is preferably 0.1 to 20 mm, and 0.1 to 5 mm.
Is more preferred. Although the resistance value of the resistance heating element can be varied depending on its width or thickness, the above range is most practical.

The resistance heating element may have a rectangular or elliptical cross section, but is preferably flat. This is because the flat surface is more likely to dissipate heat toward the heating surface, so that the temperature distribution on the heating surface is less likely to occur. The aspect ratio of the cross section (the width of the resistance heating element / the thickness of the resistance heating element) is 10 to 50.
00 is desirable. By adjusting to this range, the resistance value of the resistance heating element can be increased, and the uniformity of the temperature of the heating surface can be ensured.

When the thickness of the resistance heating element is constant, if the aspect ratio is smaller than the above range, the amount of heat transmission in the direction of the heating surface of the ceramic substrate is reduced, and the heat distribution approximates the pattern of the resistance heating element. If the aspect ratio is too large, on the other hand, if the aspect ratio is too large, the temperature immediately above the center of the resistance heating element becomes high, and eventually, a heat distribution similar to the pattern of the resistance heating element occurs on the heating surface. Would. Therefore, considering the temperature distribution, the aspect ratio of the cross section is 1
It is preferably from 0 to 5000.

Regarding the variation of the resistance value of the resistance heating element, the variation of the resistance value with respect to the average resistance value is preferably 5% or less, more preferably 1%. It is desirable that the resistance heating element of the present invention is divided into a plurality of circuits. However, by reducing the variation of the resistance value in this way, the number of divisions of the resistance heating element can be reduced and the temperature can be easily controlled. Can be. Further, it is possible to make the temperature of the heating surface uniform during the transition of the temperature rise.

Normally, such a resistance heating element is formed by applying a conductive paste containing metal particles or conductive ceramic particles for securing conductivity on a ceramic substrate and firing it. Note that the resistance heating element may be formed using a physical vapor deposition method such as a plating method or sputtering. In the case of plating, a resistive heating element can be formed by forming a plating resist, and in the case of sputtering or the like, by performing selective etching.

The conductive paste is not particularly limited, but preferably contains not only the metal particles or the conductive ceramic but also a resin, a solvent, a thickener and the like.

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

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.

As the conductor paste, it is preferable to use a paste obtained by adding a metal oxide to metal particles, apply this on a ceramic substrate, and then sinter the metal particles and the metal oxide. . By sintering the metal oxide together with the metal particles in this manner, the ceramic substrate, such as a nitride ceramic, and the metal particles can be more closely adhered to each other.

It is not clear why the mixing with the metal oxide improves the adhesion to the nitride ceramic or the like. However, the surface of the metal particles or the surface of the nitride ceramic or the like is slightly oxidized to form an oxide film. It is considered that these oxide films are sintered and integrated via the metal oxide, and the metal particles and the nitride ceramics or the like adhere to each other. Further, when the ceramic constituting the ceramic substrate is an oxide ceramic, the surface is naturally made of an oxide, so that a conductor layer having excellent adhesion is formed.

As the metal oxide, for example,
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
Nitriding of metal particles without increasing the resistance of the heating element
Can improve the adhesion to ceramics etc.
It is.

The ratios of the above-mentioned lead oxide, zinc oxide, silica, boron oxide (B ₂ O ₃ ), alumina, yttria, and titania are 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 within a range not exceeding 100 parts by weight. By adjusting the amounts of these oxides within these ranges, the adhesion to nitride ceramics and the like 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 1 mΩ.
/ □ to 10Ω / □ are preferred. Area resistivity is 1mΩ / □
If the area resistivity is less than 10 Ω / □, the heat generation becomes large with respect to the applied voltage when the area resistivity exceeds 10 Ω / □. This is because it is difficult to control the amount of heat generated by the resistance heating element. From the viewpoint of controlling the amount of generated heat, the area resistivity of the resistance heating element is more preferably 1 to 50 mΩ / □. However, when the sheet resistivity is increased, the pattern width (cross-sectional area) can be increased, and the problem of disconnection hardly occurs. Therefore, in some cases, it is preferable to set the resistance to 50 mΩ / □ or more.

The metal used for forming the metal coating layer is not particularly limited as long as it is a non-oxidizing metal, and specific examples thereof include gold, silver, palladium, platinum and nickel. . These may be used alone or in combination of two or more. Of these, nickel is preferred. Further, the resistance heating element requires a terminal for connection to a power supply, and this terminal is attached to the resistance heating element via solder, but nickel prevents heat diffusion of the solder. Examples of the connection terminal include those made of Kovar.

Next, the hot plate unit 1 of the present invention
An example of a method of manufacturing the ceramic heater 1 constituting the ceramic heater 00 will be described with reference to the cross-sectional views shown in FIGS. 6A to 6D. Further, a method of assembling the hot plate unit 100 using the ceramic heater 1 will be described in a simplified manner. Will be described.

(1) Preparation of Green Sheet First, a ceramic sheet such as a nitride ceramic or a carbide ceramic is mixed with a binder and a solvent to obtain a green sheet 70. As ceramic powder, for example,
Aluminum nitride powder, silicon nitride powder, or the like can be used. Further, a sintering aid such as yttria 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. A paste obtained by mixing these is formed into a sheet by a doctor blade method to produce a green sheet 70. The thickness of the green sheet 70 is preferably about 0.1 to 5 mm.
In the green sheet 70, a through hole is formed at a portion where a through hole is formed by punching or the like. In addition,
In the green sheet 70, it is also possible to form a through hole in a portion to be the through hole 5.

Next, a conductive paste is filled into the through holes of the green sheet 70 to obtain a filling layer 78, and then a conductive paste serving as a resistance heating element is printed on the green sheet 70. The printing is performed so as to obtain a desired aspect ratio in consideration of the shrinkage ratio of the green sheet 70, thereby obtaining the conductive paste layer 72. The conductor paste is a high-viscosity fluid containing conductive ceramics, metal particles, and the like.

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

The average particle size of the conductive ceramic particles and metal particles is preferably 0.1 to 5 μm. This is because it is difficult for these particles to print the conductor paste even if they are too large or too small. As such a paste, 85 to 97 parts by weight of metal particles or conductive ceramic particles, 1.5 to 10 parts by weight of at least one binder selected from acrylic, ethyl cellulose, butyl cellosolve and polyvinyl alcohol, α-terpineol, glycol A paste for a conductor prepared by mixing 1.5 to 10 parts by weight of at least one solvent selected from ethyl alcohol and butanol is most suitable.

(2) Preparation of Green Sheet Laminate Next, as shown in FIG. 6A, a green sheet 70 having a filling layer 78 and a conductive paste layer 72, and a filling layer 78 and a conductive paste layer 72 are provided. And a green sheet 70 not to be laminated. The filling layer 78 is provided on the resistance heating element forming side.
And green sheet 7 having no conductive paste layer 72
The reason why 0 is laminated is to prevent the end face of the through hole from being exposed and being oxidized during firing for forming the resistance heating element. If baking for forming the resistance heating element is performed while the end face of the through hole is exposed, it is necessary to sputter a hardly oxidizable metal such as nickel, and more preferably, to coat with Au-Ni gold solder. Is also good.

(3) Firing the laminate Next, as shown in FIG. 6B, the laminate is heated and pressed to form a green sheet laminate. Thereafter, the green sheet and the conductive paste are sintered.
The temperature at the time of firing is 1700 to 2000 ° C, and the pressure at the time of firing is 10 to 20 MPa (100 to 200 kg /
cm ² ) is preferred. These heating and pressurizing are performed under an inert gas atmosphere. As the inert gas, argon, nitrogen, or the like can be used. In this firing step, the through holes 8, the resistance heating elements 2, and the like are formed. Further, it is desirable to form a concave portion 6a for inserting and fixing the support pin 6 in the obtained sintered body.

(4) Mounting of Terminals and the like Next, a blind hole 7 for connecting an external terminal is provided.
Into the washer 9. The washer 9 has a coefficient of thermal expansion between the ceramic substrate 1a and the lead wire 19, functions as a buffer, and is preferably conductive. Further, a through hole 5 through which the lifter pin is inserted and a bottomed hole 4 into which the temperature measuring element 3 such as a thermocouple is embedded are formed in the ceramic substrate 1a (see FIG. 6C).

Finally, as shown in FIG. 6D, a lead wire 19 is inserted into the center hole of the washer 9, and the washer 9 and the lead wire 19 are bonded to the ceramic substrate 1a by soldering, brazing, or the like. At the same time, the lead wire 19 is connected to the resistance heating element 2 via the through hole 8. As the solder, alloys such as silver-lead, lead-tin, and bismuth-tin can be used. The thickness of the solder layer is
0.1 to 50 μm is desirable. This is because the range is sufficient to secure the connection by soldering.

Further, a temperature measuring element 3 such as a thermocouple is inserted into a bottomed hole 4 provided on the bottom surface of the ceramic substrate 1a, and is fixed with a heat-resistant insulating member such as a silicone resin. By inserting and fixing the pins 6, the manufacture of the ceramic heater 1 is completed.

(5) Preparation of Support Container Next, a support container 10 as shown in FIG. 1 is prepared. The support container 10 has a cylindrical shape with a bottom, and it is desirable that the outer frame portion 17 and the bottom portion 12 are formed integrally. A screw hole 21 is formed in the bottom portion 12, and a deflection adjusting screw 20 is provided in the screw hole 21. Further, it is also possible to provide a coolant introduction pipe 16 for supplying a coolant for forced cooling in the bottom portion 12 and to form a through hole 12a for discharging the supplied coolant. Further, a reinforcing member 28 as shown in FIG. 3 may be formed on the lower surface of the bottom portion 12. (6) Assembly of Hot Plate Unit After this, the obtained ceramic heater 1 was connected to the ceramic heater 1 via bolts 18 as shown in FIG.
The bottom portion 12 of the support container 10 is separated from the support container 10 by a predetermined distance, and is supported and fixed to the support container 10 so that the outer frame portion 17 constituting the support container 10 and the ceramic heater 1 are in a non-contact state. Then, the wiring from the temperature measuring element 3 and the resistance heating element 2 is provided, and the lead wire 19 is drawn out from the bottom portion 12, thereby completing the manufacture of the hot plate unit 100.

Next, the hot plate unit 5 of the present invention
An example of a method for manufacturing the ceramic heater 51 constituting the first embodiment will be described with reference to the cross-sectional views shown in FIGS.
Further, a method of assembling the hot plate unit 500 using the ceramic heater 51 will be briefly described.

(1) Step of Manufacturing Ceramic Substrate The above-mentioned ceramic powder such as nitride such as aluminum nitride or silicon carbide is added to yttria (Y ₂ O ₃ ) as necessary.
And a sintering aid such as B ₄ C, a compound containing Na and Ca, a binder, etc. are blended to prepare a slurry, and then the slurry is granulated by a method such as spray-drying, and the granules are formed into a mold or the like. It is molded into a plate shape by putting and pressing,
A green form is produced. Next, the formed body is heated, fired and sintered to produce a ceramic plate. Thereafter, the ceramic substrate 51a 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 baking while applying pressure, it is possible to manufacture a ceramic substrate 51a having no pores. Heating and firing may be performed at a sintering temperature or higher.
0 to 2500 ° C. In oxide ceramics,
1500 ° C to 2000 ° C.

Next, if necessary, a portion serving as a through hole 55 into which a lifter pin for supporting a semiconductor wafer is inserted, a temperature measuring element 53 such as a thermocouple, or the like is provided on the ceramic substrate 51a.
Is formed as a bottomed hole 54 for embedding a hole. Further, it is desirable to form a concave portion 56a for inserting and fixing the support pin (see FIG. 7A).

(2) Step of Printing Conductive Paste on Ceramic Substrate The conductive paste is a highly viscous fluid composed of metal particles composed of two or more kinds of noble metals, a resin, and a solvent. This conductor paste is formed by screen printing or the like to form a conductor paste layer serving as a resistance heating element pattern.

At this time, a conductor paste layer is formed on the outermost periphery of the ceramic substrate 51a so as to form at least two circuits divided in the circumferential direction, and the inside of the conductor paste layer printed on the outermost periphery is formed. Then, it is desirable to form a conductor paste layer that becomes another circuit. The pattern formed on the outermost periphery of the ceramic substrate as the resistance heating element pattern includes, for example, a repetition pattern of arcs, a repetition pattern of bending lines, and the like. The pattern formed therein may be, for example, a concentric pattern. Further, it is desirable that the conductive paste layer be formed such that the cross section of the resistance heating element 52 after firing has a rectangular and flat shape.

(3) Firing of Conductive Paste The conductive paste layer printed on the bottom surface of the ceramic substrate 51a is heated and fired to remove the resin and the solvent, sinter the metal particles, and baked on the bottom surface of the ceramic substrate 51a. The resistance heating element 52 is formed (see FIG. 7B). The temperature of the heating and firing is preferably from 500 to 1000C. If the above-described oxide is added to the conductor paste, the metal particles, the ceramic substrate and the oxide are sintered and integrated, so that the adhesion between the resistance heating element and the ceramic substrate is improved.

(4) Formation of Metal Coating Layer A metal coating layer 520 is provided on the surface of the resistance heating element 52 (see FIG. 7C). The metal coating layer 520 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 Terminals (external terminals 63) for connection to a power supply are attached to the end of the pattern of the resistance heating element 52 by soldering. Further, a temperature measuring element 5 such as a thermocouple or the like with
3 is fixed and sealed with a heat-resistant resin such as polyimide.
6a, by inserting and fixing the support pin 56,
The manufacture of the ceramic heater 51 ends (see FIG. 7D).

(6) Preparation of Support Container Next, a support container 60 as shown in FIG. 4 is prepared. The support container 60 has a bottomed cylindrical shape similarly to the hot plate unit 100, and it is desirable that the outer frame 67 and the bottom 62 are formed integrally. A screw hole 31 is formed in the bottom portion 62 so that the deflection adjusting screw 30 does not come into contact with the resistance heating element 52 formed on the bottom surface of the ceramic substrate 51a. The screw 30 is provided. Further, it is also possible to provide a coolant introduction pipe 66 for supplying a coolant for forced cooling in the bottom portion 62, and to form a through hole 62a for discharging the supplied coolant. Further, a reinforcing member 58 as shown in FIG. 3 may be formed on the lower surface of the bottom portion 62.

(7) Assembly of hot plate unit After this, the obtained ceramic heater 51 is connected to the ceramic heater 51 via bolts 68 as shown in FIG.
And the bottom portion 62 of the support container 60 are separated by a predetermined distance, and the outer frame 67 and the ceramic heater 1 that constitute the support container 60 are separated.
Is supported by the support container 60 so that
Fix it. Then, the wiring from the temperature measuring element 53 and the resistance heating element 52 is provided, and the lead wire 69 is drawn out from the bottom part 62, thereby completing the manufacture of the hot plate unit 500.

Although the hot plate unit has been described above, an electrostatic chuck may be provided by providing a resistance heating element on the surface or inside the ceramic substrate and providing an electrostatic electrode inside the ceramic substrate. In the ceramic heater of the present invention, an electrostatic chuck may be provided by providing an electrostatic electrode, or a chuck top plate for a wafer prober may be provided by providing a chaptop conductor layer.

[0120]

The present invention will be described in more detail below.

Example 1 Production of Hot Plate Unit (See FIGS. 1, 2, 3 and 6) (1) 100 parts by weight of aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm), yttria (average particle size) Diameter 0.
4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight,
Using a paste obtained by mixing 0.5 parts by weight of a dispersant and 53 parts by weight of alcohol composed of 1-butanol and ethanol, the mixture was molded by a doctor blade method to a thickness of 0.1 part.
A 47 mm green sheet 70 was obtained.

(2) Next, this green sheet 70 is
After drying at 5 ° C. for 5 hours, a diameter of 1.8 was punched.
mm, 3.0 mm, and 5.0 mm through holes were respectively formed. These through holes are a portion to be a through hole 5 for inserting a lifter pin, a portion to be a through hole 8, and the like. (3) Tungsten carbide particles 1 having an average particle diameter of 1 μm
A conductor paste A was prepared by mixing 00 parts by weight, 3.0 parts by weight of an acrylic binder, 3.5 parts by weight of an α-terpineol solvent and 0.3 part by weight of a dispersant.

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 part by weight of a dispersant.

The conductor paste A was printed on a green sheet by screen printing to form a conductor paste layer 72 to be the resistance heating element 52. As shown in FIG. 2, the printing pattern used was a combination of a repetition pattern of circular arcs and a pattern consisting of concentric circles. In addition, the conductive paste B was filled in the through-hole portion to be the through hole 8. On the green sheet after the above-mentioned processing, 37 green sheets which have not been subjected to a printing process are laminated on the upper side (heating surface) and 13 on the lower side, and integrated at 130 ° C. and a pressure of 8 MPa (80 kg / cm ² ). Thus, a laminate was produced (see FIG. 6A).

(4) Next, the obtained laminate is placed in nitrogen gas.
Degreasing at 600 ° C for 5 hours, 1890 ° C, pressure 15MPa
(150kg / cm ²⁾ at 10 hours hot pressed to obtain an aluminum nitride plate-like body having a thickness of 3 mm. This is 21
Cut out into a 0 mm disk shape and have a thickness of 6 μm and a width of 10
This was a ceramic substrate 1a having a resistance heating element 2 of 1 mm. The size of the through hole 8 is 0.2 m in diameter.
m and a depth of 0.2 mm. Then, after polishing the obtained plate-like body with a diamond grindstone, a mask is placed,
Four pits 6a each having a diameter of 3 mm and a depth of 2 mm were formed at equal intervals on the surface by blasting with SiC or the like (FIG. 6).
(B)).

(5) Further, a mask is placed on the surface of the obtained plate-shaped body where no concave portion is formed, and a bottomed hole 4 for the temperature measuring element 3 is formed on the surface by blasting with SiC or the like. Provided and drilled 5mm in diameter and 0.5m deep
A bag hole 7 of m was formed (see FIG. 6C).

(6) A washer 9 made of W is fitted into the blind hole 7, and a lead wire 19 is inserted into the center hole of the washer 9, and then a Ni-Au alloy (Au: 81.5% by weight, Ni:
(18.4% by weight, impurity: 0.1% by weight), and by heating and reflowing at 970 ° C., the washer 9 and the lead wire 19 were connected to the ceramic substrate 1.
a. Then, an alumina support pin 6 (length: 2.1 mm) was fitted into the recess 6a. Further, the temperature measuring element 3 was embedded in the bottomed hole 4, and the manufacture of the ceramic heater 1 in which the resistance heating element 2 was embedded was completed (see FIG. 6D). Note that the support pins 6 protruded from the heating surface of the ceramic heater 1 by 100 μm.

(7) Next, as shown in FIG.
7 (thickness: 2 mm) and the bottom part 12 (thickness: 2 mm) are integrated, and a SUS support container 10 having a reinforcing member 28 formed thereon as shown in FIG. did. On the bottom 12, six deflection adjusting screws 20 are arranged at regular intervals so as to be in contact with the circumference of a concentric circle with the ceramic substrate.
And 1 so as to be in contact with the center of the ceramic substrate.
So that a total of seven screw holes 21 can be arranged.
Was formed. Then, in the screw hole 21, a bending adjustment screw 20 (outer diameter: 4 mm) made of quartz was provided.

(8) Thereafter, the ceramic heater 1 is replaced with the one shown in FIG.
As shown in the figure, while being supported and fixed to the supporting container 10 having the above-described configuration via eight bolts 18 (outer diameter: 4 mm), the lead wires 19 from the resistance heating element 2 and the temperature measuring element 3 are connected. The drawer and the manufacture of the hot plate unit 100 were completed.

Example 2 Production of Hot Plate Unit (See FIGS. 4, 5 and 7) (1) Aluminum Nitride Powder (Average Particle Size: 1.1 μm) 1
A composition comprising 00 parts by weight, 4 parts by weight of yttria (average particle size: 0.4 μm), 12 parts by weight of an acrylic binder and alcohol was spray-dried to prepare a granular powder.

(2) Next, the granular powder was put into a mold and molded into a flat plate to obtain a formed product (green). (3) The processed form is processed at 1800 ° C., pressure: 2
Hot pressing was performed at 0 MPa to obtain an aluminum nitride plate having a thickness of 3 mm. Next, a diameter 310
mm was cut out to obtain a ceramic plate-like body (ceramic substrate) 51a.

Drilling is performed on this molded body to form a portion serving as a through hole 55 for inserting a lifter pin for supporting a semiconductor wafer, and a portion serving as a bottomed hole 54 for embedding a temperature measuring element 53 such as a thermocouple (diameter: 1.1 mm, depth: 2 mm)
Was formed. Also, a mask was placed, and five concave portions 56a having a diameter of 3 mm and a depth of 2 mm were formed at regular intervals on the surface opposite to the surface on which the bottomed holes 54 were formed by blasting with SiC or the like (FIG. 7 (a)).

(4) The ceramic substrate 51a obtained in the above (3)
Then, a conductor paste was printed by screen printing, and a conductor paste layer was formed so as to be a resistance heating element 52 having a repeating pattern of bent lines. 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,
A metal oxide composed of lead oxide (5% by weight), zinc oxide (55% by weight), silica (10% by weight), boron oxide (25% by weight), and alumina (5% by weight) was added to 00 parts by weight. It contained 7.5 parts by weight. The silver particles had an average particle size of 4.5 μm and were scaly.

(5) Next, the ceramic substrate 51a on which the conductor paste is printed is heated and baked at 780 ° C. to sinter silver and lead in the conductor paste and to form the ceramic substrate 5a.
1a to form a resistance heating element 52 (FIG. 7).
(B)). The silver-lead resistance heating element 52 has a thickness of 5 μm.
m, the width was 2.4 mm, and the sheet resistivity was 7.7 mΩ / □.

(6) The above electroless nickel plating bath consisting of an aqueous solution having a concentration of 80 g / l of nickel sulfate, 24 g / l of sodium hypophosphite, 12 g / l of sodium acetate, 8 g / l of boric acid, and 6 g / l of ammonium chloride was used. The ceramic substrate 51a prepared in (5) was immersed to deposit a metal coating layer (nickel layer) having a thickness of 1 μm on the surface of the silver-lead resistance heating element 52 (see FIG. 7C).

(7) A silver-lead solder paste (manufactured by Tanaka Kikinzoku Co., Ltd.) was printed by screen printing on a portion where a terminal for securing connection to a power supply was to be formed, to form a solder layer. Then, an external terminal 63 made of Kovar was placed on the solder layer, and heated and reflowed at 420 ° C., and the external terminal 63 was attached to the surface of the resistance heating element 52.

(8) A temperature measuring element 53 for temperature control is fitted into the bottomed hole 54, and a ceramic adhesive (manufactured by Toa Gosei Co., Ltd.)
Aron ceramic) was embedded and fixed. Then, an alumina support pin 56 (length: 2.1
mm) to obtain a ceramic heater 51 (FIG. 7).
(D)). Note that the support pins 56 protruded from the heating surface of the ceramic heater 51 by 100 μm.

(9) Next, as shown in FIG.
7 (thickness: 2 mm) and a bottom portion 62 (thickness: 2 mm) were integrated, and a support container 60 made of SUS having a reinforcing member 58 formed on the upper surface of the bottom portion 62 was produced. The bottom portion 62 may be provided with six flexure adjusting screws 30 at regular intervals so as to be in contact with the circumference of a concentric circle with the ceramic substrate and one to be in contact with the center portion of the ceramic substrate. A total of seven screw holes 31 were formed as possible. Then, in the screw hole 31, a deflection adjusting screw 30 (outer diameter: 4 mm) made of quartz was provided.

(10) Thereafter, as shown in FIG. 4, the ceramic heater 51 is connected to twelve bolts 68 (outer diameter: 4 m
Through m), while being supported and fixed to the support container 60 having the above-described configuration, the lead wires 69 from the resistance heating element 52 and the temperature measuring element 53 were pulled out, and the production of the hot plate unit 500 was completed.

(Comparative Example 1) Manufacture of hot plate unit Except that the screw hole 21 was not formed in the bottom portion 12 of the support container 10 and the deflection adjusting screw 20 was not provided, the same as in Example 1 was performed. Manufactured a hot plate unit.

(Comparative Example 2) Manufacture of hot plate unit In the same manner as in Example 2 except that the screw hole 31 was not formed in the bottom portion 62 of the support container 60 and the deflection adjusting screw 30 was not provided. Manufactured a hot plate unit.

The hot plate units according to Examples 1 and 2 and Comparative Examples 1 and 2 obtained through the above steps were evaluated by the following indexes. Table 1 shows the results.
In the hot plate units according to Examples 1 and 2, a temperature rise test was performed in advance, and the amount of deflection of the ceramic substrate was determined.
After examining the temperature relationship and adjusting the tightening of the deflection adjusting screw, the temperature was raised.

[0143]Evaluation method  (1) Flatness measurement When the temperature of the hot plate unit is raised to 300 ° C
Laser flatness of heating surface of ceramic heater
(Manufactured by Keyence Corporation). Table 1 shows the results.
Shown in The flatness refers to the heating surface of the ceramic heater.
The difference between the highest and lowest parts of
And

(2) Temperature uniformity within the heating surface A silicon wafer (thickness:
(0.7 mm), and the temperature was raised to 300 ° C., and the highest and lowest temperatures on the silicon wafer surface were measured with a thermoviewer (IR-16-2012-001 manufactured by Nippon Datum Co., Ltd.).
It measured by 2). The results are shown in Table 1.

[0145]

[Table 1]

As is clear from Table 1, the hot plate unit according to the embodiment has a flat heating surface of the ceramic heater and the silicon wafer as the object to be heated, as compared with the hot plate unit according to the comparative example. Was heated uniformly. This is because, in the hot plate unit according to the embodiment, a screw hole is formed in the bottom of the support container as a deflection adjusting means, and a screw for adjusting the deflection is provided in the screw hole. Since the amount of deflection of the ceramic substrate of the ceramic substrate can be adjusted by using the adjusting unit, the flatness of the heating surface of the ceramic heater can be ensured, and the semiconductor wafer to be heated can be uniformly heated. On the other hand, the hot plate unit according to the comparative example was not provided with the bending adjusting means, and the amount of bending of the ceramic substrate could not be adjusted. Therefore, it is considered that the semiconductor wafer as the object to be heated could not be uniformly heated.

[0147]

As described above, according to the ceramic heater of the present invention, since the supporting container is provided with the bending adjusting means for adjusting the amount of bending of the ceramic substrate, the bending adjusting means is used. Thus, the amount of deflection of the ceramic substrate can be adjusted. As a result, the flatness of the heating surface of the ceramic heater can be ensured, and the semiconductor wafer to be heated can be uniformly heated.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view schematically showing a hot plate unit of the present invention, and FIG. 1B is a partially enlarged cross-sectional view thereof.

FIG. 2 is a plan view schematically showing the hot plate unit of FIG. 1;

FIG. 3 is a perspective view schematically showing a support container used in the hot plate unit of FIG. 1;

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

FIG. 5 is a plan view schematically showing the hot plate unit shown in FIG. 3;

FIGS. 6A to 6D are cross-sectional views schematically showing a part of a method for manufacturing a ceramic heater used in the hot plate unit shown in FIG.

FIGS. 7A to 7D are cross-sectional views schematically showing a part of a method of manufacturing a ceramic heater used in the hot plate unit shown in FIG.

[Explanation of symbols]

 1, 51 Ceramic heater 100, 500 Hot plate unit 1a, 51a Ceramic substrate 2 (2a to 2g), 52 (52a to 52l) Resistance heating element 520 Metal coating layer 3, 53 Temperature measuring element 4, 54 Bottomed hole 5, 55 through hole 7 blind hole 8 through hole 9 washer 10, 60 support container 11, 61 middle bottom plate 12, 62 bottom 12a through hole 13, 63 external terminal 14, 64 socket 15, 65 guide tube 16, 66 refrigerant introduction tube 17, 67 Outer frame portion 18, 68 Bolt 20, 30 Deflection adjusting screw 21, 31 Screw hole 28, 58 Reinforcing member 29 Semiconductor wafer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 3/16 H05B 3/18 3/18 3/20 393 3/20 393 H01L 21/30 567 F term ( Reference) 3K034 AA02 AA03 AA05 AA08 AA12 AA16 AA19 BA12 BA17 BB06 BB14 BC04 BC12 BC16 CA02 CA15 CA26 DA04 DA05 GA02 GA03 GA04 GA11 3K092 PP20 QA05 QB02 QB08 QB17 QB26 QB43 QB48 QB75 RFBQ QC02 RFB1 QC02 RFB1 QC02 HA16 HA37 MA28 MA29 MA32 MA33 PA13 5F046 KA04 KA10

Claims (2)

[Claims] A hot plate unit including a ceramic substrate having a resistance heating element formed on the surface or inside thereof, and a bottomed cylindrical support container for supporting the ceramic substrate, wherein the support container has A hot plate unit provided with a bending adjusting means for adjusting a bending amount of the ceramic substrate. 2. The hot plate unit according to claim 1, wherein a screw hole is formed in a bottom portion of the support container as the bending adjusting means, and a bending adjusting screw is provided in the screw hole. .