JP2002313539A - Planar ceramic heater and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar ceramic heater and a method of manufacturing the planar ceramic heater with excellent durability, always securing stable heat generation and heat radiation by stably ensuring electric power supply to a resistance heating element by an electric power supply terminal. SOLUTION: This planar ceramic heater has a planar ceramic base material 3 one main face of which forms a radiating-heating face; the resistance heating element 4 arranged being embedded in the ceramic base material 3; and the electric power supply terminal 1 made of tungsten or molybdenum, with one end connected to the resistance heating element 4 and with the other end side led out to the other main face side of the ceramic base material 3. At least the outer peripheral surface, exposed to a high temperature atmosphere, of the electric power supply terminal 1 is fittingly covered with a sintered aluminum nitride sleeve 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar ceramic heater and a method for manufacturing the same, and more particularly, to a planar ceramic heater which imparts oxidation resistance to a power supply terminal to maintain stable heat radiation and heat generation, and a method for manufacturing the same. It relates to a manufacturing method.

For example, in the production of semiconductors, semiconductor wafers are subjected to processing such as PVD, plasma CVD, plasma etching, and optical etching.
In addition, these processings are generally performed while arranging a workpiece on a planar ceramic heater (heating element) and heating the workpiece. In order to obtain a semiconductor having high performance or high reliability with good yield and mass production, heat treatment is one important factor.

[0003] Here, the planar ceramic heater includes, for example, a resistance heating wire (or a coil) such as a tungsten wire or a molybdenum wire inside a dense and gas-tight ceramic sintered body (ceramic base material), for example, a spiral or ceramic wire. It is buried in a zigzag shape. The power supply terminal for the resistance heating element has a structure led out of the ceramic base. The power supply terminal is made of, for example, tungsten, molybdenum, nickel, or the like, and the ceramic base is made of, for example, alumina, silica, aluminum nitride, silicon nitride, or sialon. Aluminum nitride is attracting attention in terms of thermal conductivity and corrosion resistance.

[0004] This type of ceramic heater is generally manufactured by the following means. First
Means of ceramic base material (green sheet)
On one main surface, a resistance heating element formed by the resistance heating wire is arranged, and while a heater cover sheet is laminated on the resistance heating element surface, a power supply terminal is inserted and incorporated into the cover sheet, and then a predetermined condition is applied. In this method, degreasing is performed, hot pressing is performed at a required temperature, and the like is sintered and integrated.

[0005] A second means is to prepare a plate-shaped ceramic base material forming a heat-radiating / heat-generating surface and a plate-shaped ceramic base material forming a heater cover in advance. This is a method in which a resistance heating element formed by a heating wire is arranged, and a bonding agent layer is interposed to be joined and integrated. Here, a hole corresponding to a connected portion of the resistance heating element is formed in the plate-shaped ceramic base material forming the heater cover, and a power supply terminal is attached to the formed hole, and the conductive material is electrically conductive. The electrical connection is made by filling the paste. In any of the first and second means, the formation of the resistance heating element is also performed by screen printing and baking of the resistance heating element paste, laser processing of a tungsten plate, punching punching, or the like.

[0006]

By the way, in the heat treatment in the manufacturing process of the semiconductor, the durability and good yield of the planar ceramic heater used as the heating source are reduced in view of the working rate and the cost reduction. It is a precondition for securing. In other words, in a planar ceramic heater,
It is required to maintain stable heat radiation / heat generation capacity, uniformity of in-plane temperature distribution, and the like. However, in the configuration of the conventional planar ceramic heater, the power supply terminal is likely to be deteriorated, and there are problems in durability, stable heat radiation, heat generation, and the like.

That is, when the planar ceramic heater is mounted, for example, as a component of a semiconductor manufacturing apparatus, the heat-radiating / heat-generating main body (ceramic base material in which a resistance heating element is embedded) mounts and processes a semiconductor wafer. For this purpose, it is mounted in a processing chamber in which the atmosphere can be appropriately adjusted. On the other hand, the power supply terminal is usually led out through the wall of the processing chamber into the atmosphere outside the processing chamber, and is set so as to easily supply required power from the outside.

[0008] Further, in the configuration of the manufacturing apparatus, it can be said that the power supply terminal is led out to the atmosphere when the planar ceramic heater performs a heat radiation / heat generation operation.
The temperature rises to a considerably high temperature because it is adjacent to the processing chamber of several hundred degrees Celsius. That is, the power supply terminal made of tungsten inevitably takes a state of being exposed to the high-temperature atmosphere, so that the oxidation reaction proceeds in the exposed region. In addition, the progress of the oxidation reaction not only causes a decrease in the power supply capacity or power supply capability of the power supply terminal, but also causes a decrease in mechanical strength of the power supply terminal, greatly impairing durability and the like. Become.

As described above, in the case of the conventional planar ceramic heater, there is a possibility that heat generation and heat dissipation may be impaired due to a function deterioration phenomenon caused by oxidation of the power supply terminal. That is, the difficulty of constantly supplying the required power and the difficulty of maintaining a uniform in-plane temperature distribution impair, for example, semiconductor manufacturing / processing efficiency or productivity. In addition, such a problem poses a serious problem in increasing productivity by increasing the diameter of a semiconductor wafer or the like. In other words, in response to the increase in the diameter of the workpiece, the surface ceramic heater also needs to have a large diameter, and at this time, the stability of the heat radiation and heating temperature required for the surface ceramic heater is impaired. Cannot respond to the improvement of productivity.

The present invention has been made in view of the above circumstances, and has an excellent durability in which power supply from a power supply terminal to a resistance heating element is stably ensured, and stable heat generation and heat radiation are always obtained. It is an object of the present invention to provide a ceramic heater and a method for manufacturing the same.

[0011]

According to a first aspect of the present invention, there is provided a planar ceramic base material having one main surface serving as a heat radiating / heating surface, a resistance heating element embedded and arranged in the ceramic base material, A planar ceramic heater having a tungsten or molybdenum power supply terminal, one end of which is connected to the resistance heating element and the other end of which is led out to the other main surface of the ceramic base material, wherein at least the high temperature of the power supply terminal is high. A planar ceramic heater characterized in that the outer peripheral surface exposed to the atmosphere is fitted and covered by a sintered aluminum nitride sleeve.

According to a second aspect of the present invention, in the planar ceramic heater according to the first aspect, the thickness of the sintered aluminum nitride sleeve to be fitted and covered is 0.1 to 3 mm.

According to a third aspect of the present invention, in the planar ceramic heater according to the first or second aspect, the insertion hole of the ceramic base for inserting the power supply terminal and the tapered engagement corresponding to the power supply terminal. And the power supply terminal is connected to the resistance heating element by a pressure transmitted through the taper.

The invention according to claim 4 is a step of positioning and arranging a resistance heating element having a connected terminal portion on the other main surface side of the first planar ceramic base material whose one main surface forms a heat dissipation / heating surface;
Laminating and integrating a second planar ceramic base material for inserting a tungsten or molybdenum power supply terminal connected to the connected terminal portion of the resistance heating element on the resistance heating element arrangement surface. A method for manufacturing a ceramic heater, comprising: fitting and covering a sintered aluminum nitride sleeve on at least an outer peripheral surface of a power supply terminal to be inserted into the second planar ceramic substrate, which is exposed to a high-temperature atmosphere. This is a method for manufacturing a planar ceramic heater characterized by the following.

According to a fifth aspect of the present invention, in the method for manufacturing a planar ceramic heater according to the fourth aspect, the power supply terminal insertion hole and the power supply terminal of the second planar ceramic base material are processed with corresponding tapered portions. In addition, the connection of the power supply terminal to the resistance heating element is facilitated by the taper transmission of the pressing force for lamination and integration.

According to the first to fifth aspects of the present invention, a resistance heating element is embedded and arranged in a ceramic substrate, and a tungsten or molybdenum power supply terminal connected to the resistance heating element is led out of the ceramic substrate. In the configuration of the planar ceramic heater, at least the outer peripheral surface of the power supply terminal exposed to the high-temperature atmosphere is fitted and covered with a sintered aluminum nitride sleeve having substantially the same coefficient of thermal expansion to provide oxidation resistance. And That is, the outer peripheral surface of the power supply terminal, which is easily heated to a high temperature and exposed to the atmosphere, is covered with a sintered aluminum nitride layer having substantially the same coefficient of thermal expansion, and the power supply terminal is stabilized by cutting off the contact with the atmosphere. The function or performance is maintained and exhibited.

In the first to fifth aspects of the present invention, the planar ceramic substrate is made of, for example, an alumina-based or silica-based material.
Examples thereof include aluminum nitride, silicon nitride, and sialon. Aluminum nitride is particularly preferable in terms of thermal conductivity and corrosion resistance. The resistance heating element embedded and arranged in the ceramic substrate is formed by forming a resistance heating wire (or coil) such as a tungsten wire, a molybdenum wire, a nichrome wire or the like in a spiral or zigzag shape. Further, the power supply terminal having a structure led out of the ceramic base is made of tungsten or molybdenum.

The sintered aluminum nitride sleeve for fitting and covering at least the outer peripheral surface of the power supply terminal exposed to a high-temperature atmosphere is an aluminum nitride having an average particle size of about 0.01 to 5 μm. The powder is granulated from a slurry obtained by adding and mixing a sintering aid and a binder, and this is formed into a sleeve having a required shape and dimensions.
It is produced by sintering an organic component in a high-temperature inert atmosphere of 1800 ° C. or higher or in a hydrogen gas after thermal degreasing. Specifically, an aluminum nitride sleeve molded body whose inner diameter is set so as to match the outer diameter of the power supply terminal due to shrinkage during sintering is fitted and covered on the power supply terminal, and in a high temperature inert atmosphere or the like. By sintering,
Fitting and coating with a sintered aluminum nitride sleeve are performed. The sintering aid is exemplified by yttrium oxide and the like, and the binder is exemplified by polyvinyl butyral.

When the sintered aluminum nitride sleeve is fitted to the power supply terminal in a tapered manner so as to increase the diameter of the connection side of the power supply terminal to the resistance heating element, the contact surface with the ceramic base material is widened. Therefore, it is possible to improve the bonding strength and stabilize the connection. If a groove (for example, V-shaped, square or semi-circular in cross section) is provided on the end face of the power supply terminal for the resistance heating element to engage with the connected portion, positioning is easy and reliable connection is ensured. It becomes possible to secure.

In the first to fifth aspects of the present invention, the thickness of the sintered aluminum nitride sleeve for fitting and covering the outer peripheral surface of the power supply terminal is generally about 0.1 to 3 mm, preferably 0.5 to 3 mm. It is about 1.5 mm. Here, if the sintered aluminum nitride sleeve is thin, the fitting / coating workability is reduced, and the required oxidation resistance may not be sufficiently provided. On the other hand, if the thickness is too large, the in-plane temperature distribution tends to be adversely affected.

In the first to fifth aspects of the present invention, the ceramic sintered body in which the resistance heating element is embedded / built is generally obtained by the following means. For example, an aluminum nitride-based sintered body is granulated from a slurry obtained by adding and mixing a sintering aid and a binder to aluminum nitride powder having an average particle size of about 0.01 to 5 μm, and forming the granules into a desired shape and size. After thermal degreasing of organic components,
It is manufactured by sintering in a high temperature inert atmosphere of 1800 ° C. or higher. Here, as the sintering aid, yttrium oxide or the like is exemplified, and as the binder,
Examples thereof include polyvinyl butyral. Prior to high-temperature sintering, the resistance heating element should be
It is desirable to provide a groove for embedding in advance.

When the resistance heating element is embedded in an aluminum nitride-based substrate or the like, the resistance heating element is positioned and arranged between the opposing surfaces of the aluminum nitride-based members to be combined. At this time, the power supply terminal is inserted and assembled in advance and fixed to the aluminum nitride-based member on the side from which the power supply terminal is led out. Then, a bonding agent such as an aluminum nitride-yttrium oxide-lithium oxide-based paste is printed or applied on the opposing surface of the aluminum nitride-based member to form a bonding layer. It is performed by heating at a temperature of about 1750C.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, FIGS. 1, 2 (a) and 2 (b)
An embodiment will be described with reference to FIGS. 3 (a), (b) and FIG.

First, a tungsten rod-shaped power supply terminal body having a diameter of 4 mm and a length of 300 mm was prepared in order to temporarily confirm the effect of imparting acid resistance. On the other hand, the average particle size is 0.
Granulation was performed from a slurry obtained by adding and mixing a sintering aid and a binder to an aluminum nitride powder having a size of about 01 to 5 μm, and formed into a sleeve having a required shape and size. At this time, the inner diameter of the aluminum nitride sleeve molded body is set to match the outer diameter of the rod-shaped power supply terminal main body due to shrinkage during sintering.

Next, the aluminum nitride sleeve molded body is fitted and covered with a power supply terminal, and after thermal degreasing of organic components, the aluminum nitride sleeve is formed in a high temperature inert atmosphere of 1800 ° C. or more (eg, nitrogen gas). It is produced by sintering a compact. FIG. 1 shows a cross-sectional structure of the produced power supply terminal 1, wherein 1a is a rod-shaped power supply terminal main body made of tungsten, and 1b is a sintered aluminum nitride sleeve to be fitted and covered. Further, FIG.
(A) and (b) are cross-sectional views schematically showing a state in which the aluminum nitride sleeve molded body 1b 'is fitted to the rod-shaped power supply terminal main body 1a and a state of fitting and covering after sintering, respectively. It is.

Note that the power supply terminal 1 is
(A) and (b) can be configured to show different configuration examples. That is, according to the conditions in the above embodiment, the aluminum nitride sleeve 1b having one end (the side to be connected to the resistance heating element) whose outer periphery is tapered to increase in diameter is fitted to the rod-shaped power supply terminal main body 1a. -Covered configuration (Fig. 3a) or rod-shaped power supply terminal body 1a
The outer circumference at one end is tapered to increase the diameter, and the surface of the aluminum nitride sleeve 1b can be tapered accordingly (FIG. 3B). And in the case of this tapered configuration, a resistance heating element is embedded,
In addition, the ceramic base material through which the power supply terminal 1 is inserted and drawn out is effectively subjected to the pressing force at the time of joining and integrating the ceramic base material, so that a connection with higher strength is easily formed. If the power supply terminal main body 1a connected to the resistance heating element is provided with a groove 2 that engages with the connected portion of the resistance heating element, a more reliable connection can be secured.

Next, the power supply terminal of the structure was left in the air at a temperature of 800 ° C. for 100 hours, and the oxidation resistance was examined from the weight change before and after the treatment.
It was confirmed that good oxidation resistance was exhibited at 0.05% or less. That is, the outer peripheral surface of the rod-shaped power supply terminal body 1a made of tungsten has a sintered aluminum nitride sleeve 1b.
Since they are tightly fitted and covered, they are less susceptible to oxidative degradation even when exposed to a high-temperature atmosphere, and exhibit excellent oxidation resistance.
Moreover, since the rod-shaped power supply terminal main body 1a and the sintered aluminum nitride sleeve 1b have substantially the same coefficient of thermal expansion, there is no possibility of peeling during the heating / cooling cycle, and the above-mentioned excellent oxidation resistance can be maintained for a long time. Holds and exerts throughout.

Next, an embodiment of the planar ceramic heater incorporating the power supply terminal 1 fitted and covered with the sintered aluminum nitride sleeve will be described. FIG. 4 is an enlarged cross-sectional view showing a configuration of a main part of the planar ceramic heater. Reference numeral 3 denotes an aluminum nitride-based substrate having a diameter of 230 mm.
A bonding agent between a 6 mm thick aluminum nitride base material layer 3a whose one main surface forms a heat dissipation / heating surface and a 6 mm thick aluminum nitride base material layer 3b that leads out the power supply terminal 1 to the other main surface side It is joined and integrated by hot pressing through layers (not shown). Reference numeral 4 denotes a resistance heating element made of a tungsten wire having a diameter of 0.4 mm, which is embedded between the aluminum nitride base layers 3a and 3b, and has a power supply terminal 1 corresponding to the connected terminal portion. Connected.

That is, in the configuration of the planar ceramic heater, the outer peripheral surface of the power supply terminal 1 which is at least derived from the aluminum nitride base material layer 3b and exposed to the atmosphere is covered with the sintered aluminum nitride sleeve 1b. Have been.

Next, the planar ceramic heater having the above configuration is positioned and mounted in a processing chamber of a semiconductor manufacturing CVD apparatus, the processing chamber is set to a reduced-pressure Ar-based atmosphere, and power is supplied to the planar ceramic heater. Temperature 750
It was set to be kept at ° C. In the positioning mounting of the planar ceramic heater, a part of the power supply terminal 1 is led out of the processing chamber and is exposed to the high-temperature atmosphere.

In the heating operation of the planar ceramic heater, since the property change due to oxidation of the power supply terminal 1 area exposed to the atmosphere outside the processing chamber is prevented, stable power supply is performed. That is, stable heat dissipation and heat generation in the planar ceramic heater are easily and constantly secured.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the shape and material of the resistance heating element, the material of the input power terminal, or the material, shape and dimensions of the ceramic base material can be selected and set according to the application. In addition, the present invention can be applied to a configuration of an electrostatic chuck or a susceptor with a built-in electrode.

[0033]

According to the first to third aspects of the present invention, the portion of the power supply terminal exposed to the high-temperature atmosphere is covered with a sintered aluminum nitride sleeve having substantially the same coefficient of thermal expansion. . Therefore, performance degradation due to oxidation of the power supply terminal is eliminated, and a highly durable planar ceramic heater having stable power supply capability is provided.

According to the fourth and fifth aspects of the present invention, the risk of power supply failure due to the oxidative deterioration of the power supply terminal is eliminated, and a stable planar ceramic heater suitable for semiconductor manufacturing is provided with high yield. You.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a configuration of a main part of a power supply terminal according to an embodiment.

FIGS. 2A and 2B schematically illustrate an example of a mode of manufacturing a power supply terminal according to an embodiment, in which FIG. 2A is a cross-sectional view illustrating a state in which an aluminum nitride sleeve molded body is fitted to a rod-shaped power supply terminal main body; (b) is a sectional view after sintering and integration.

FIGS. 3A and 3B are cross-sectional views showing another example of the configuration of the main part of the power supply terminal according to the embodiment, which is different from that of FIG.

FIG. 4 is a sectional view showing a configuration of a main part of the planar ceramic heater according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Power supply terminal 1a ... Power supply terminal main body 1b ... Sintered aluminum nitride sleeve 2 ... Groove for connecting the connected part of resistance heating element 3 ... Aluminum nitride base material 4 ... Resistance heating element

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 3/12 H05B 3/12 A (72) Inventor Shinichiro Aonuma 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. In the laboratory (72) Inventor Mitsuhiro Fujita 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. (72) Inventor Akira Miyazaki 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. F-term (reference) 3K034 AA02 AA04 AA10 AA33 AA34 BA06 BB06 BB14 BC17 CA02 HA01 HA04 HA10 JA10 3K092 PP20 QA05 QB02 QB26 QB30 QB31 QB62 QC02 RF03 RF11 RF27 VV09

Claims (5)

[Claims] 1. A planar ceramic substrate having one main surface serving as a heat-radiating / heating surface, a resistance heating element embedded and disposed in the ceramic substrate, and one end connected to the resistance heating element and the other end connected to the resistance heating element. A planar ceramic heater having a tungsten or molybdenum power supply terminal led out to the other main surface side of the ceramic base material, wherein at least an outer peripheral surface of the power supply terminal exposed to a high-temperature atmosphere is sintered aluminum nitride. A planar ceramic heater characterized by being fitted and covered by a sleeve. 2. The planar ceramic heater according to claim 1, wherein the thickness of the sintered aluminum nitride sleeve to be fitted and covered is 0.1 to 3 mm. 3. The connection of the power supply terminal to the resistance heating element with a pressure applied to the insertion hole of the ceramic base material into which the power supply terminal is to be inserted and the power supply terminal, and the taper transmitted. The planar ceramic heater according to claim 1, wherein the heating is performed. 4. A step of positioning and positioning a resistance heating element having a connected terminal portion on the other main surface side of the first planar ceramic base material whose one main surface forms a heat dissipation / heating surface; A step of laminating and integrating a second planar ceramic base material into which a power supply terminal made of tungsten or molybdenum to be connected to the connected terminal portion is inserted, on a surface on which the resistance heating element is arranged. A method characterized in that a sintered aluminum nitride sleeve is fitted and covered on at least an outer peripheral surface of a power supply terminal to be inserted into the second planar ceramic substrate, which is exposed to a high-temperature atmosphere. Of manufacturing ceramic heaters. 5. The power supply terminal insertion hole and the power supply terminal of the second planar ceramic base material are processed to have a corresponding taper, and power is supplied to the resistance heating element by taper transmission of a pressing force for lamination and integration. 5. The method for manufacturing a planar ceramic heater according to claim 4, wherein connection of terminals is promoted.