JP2010258276A - Anti-corrosion member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce heat conduction to a part of a base material which is covered with a film and to prevent generation of thermal stress in bent parts or fine parts of surrounding members by covering the whole surface or a part of the base material with the film whose thermal conductivity is lower than that thereof. <P>SOLUTION: The anti-corrosion member is exposed to a plasma environment. At least a part of the surface of its anti-corrosion base material 1 is covered with a film exhibiting a high corrosion resistance. The thermal conductivity of the film is lower than that of the anti-corrosion base material 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a corrosion-resistant member used in an atmosphere such as a corrosive plasma gas, and has, for example, a corrosion resistance having excellent corrosion resistance against a halogen-based corrosive gas or a halogen gas plasma used in a semiconductor device manufacturing process. It relates to members.

  Conventionally, silicon, quartz glass, and silicon carbide have been used according to applications as members used in a highly corrosive atmosphere in a semiconductor device manufacturing process. However, these materials have various problems. For example, in the presence of a highly reactive fluorine-based gas, quartz glass has a high vapor pressure of a reactive compound such as silicon fluoride and becomes a gas, corrosion proceeds, and the member disappears. In addition, silicon carbide, which has better corrosion resistance than quartz glass, is silicon-impregnated silicon carbide, so that the silicon portion disappears due to reaction with the fluorine-based gas, so that the silicon carbide particles are detached and cause particles.

On the other hand, aluminum-based materials such as aluminum, alumina and aluminum nitride are used because the vapor pressure of aluminum fluoride (AlF ₃ ) produced by reaction with fluorine gas is low.
In particular, aluminum and aluminum nitride have excellent thermal conductivity, and are used for heaters of semiconductor manufacturing apparatuses and substrates of electrostatic chucks to uniformly heat an object to be heated such as a Si wafer.

  However, since aluminum and aluminum nitride have high thermal conductivity, heat is easily transferred to the surroundings. In particular, there is a problem that heat is conducted to the curved portions and details of the surrounding members, and when thermal stress is repeatedly applied due to repeated raising and lowering of temperature, it is relatively easily cracked.

  As disclosed in Patent Document 1, a ceramic support member that supports the mounting table is formed into a complicated shape, or as disclosed in Patent Document 2, a joint between the mounting table and the supporting member. However, it has not been possible to sufficiently suppress cracking of the mounting table or the like.

Japanese Patent No. 4101425 Japanese Patent No. 3520074

  In view of the problems as described above, the present invention provides a corrosion-resistant material suitable for use in an electrostatic chuck or the like that is unlikely to crack even when thermal stress is repeatedly applied by repeated heating and cooling. To do.

The corrosion-resistant material of the present invention is a corrosion-resistant member that is exposed to a plasma environment, and at least part of the entire surface or part of the heat-resistant substrate is covered with a coating film having high corrosion resistance. It is a coating film having a thermal conductivity lower than the thermal conductivity.
The thermal conductivity of the film is 90 W / m · K or less, the relative density of the film is 50% or more and less than 98%, the material of the film is AlN, and TMA (trimethylaluminum) gas And the heat resistant base material is pyrolytic boron nitride, mixed sintered body of boron nitride and aluminum nitride, pyrolytic boron nitride coated graphite, aluminum nitride, rare earth oxide Any of aluminum oxide, silicon oxide, zirconia, sialon, graphite, and refractory metal is the main component, and the heat-resistant substrate has a heater and / or electrostatic chuck function, preferable.

  According to the present invention, it is possible to prevent cracks and breakage due to thermal stresses in curved portions and details by suppressing heat conduction at the portion of the film coated on the substrate. Furthermore, since it has high corrosion resistance, it can be used for a long time even in a highly corrosive atmosphere.

It is the figure which showed the corrosion-resistant member of Example 1 of this invention. It is the figure which showed the structure incorporating the corrosion-resistant member of Example 1 of this invention. It is the figure which showed the temperature measurement part of the built-in structure.

Hereinafter, the corrosion-resistant member of the present invention will be described.
As a result of intensive studies, the inventors have covered the entire surface or a part thereof with a film having a thermal conductivity lower than the thermal conductivity of the base material, thereby reducing the thermal conductivity of the coated part and surrounding members. The inventors have found that it is possible to prevent thermal stress from being generated in curved portions and details, and that it is possible to provide a highly corrosion-resistant film that can be used even in highly corrosive atmospheres, leading to the present invention. It was.
In the present invention, the entire surface or a part of the heat-resistant substrate is covered with a coating film having high corrosion resistance, and is covered with a coating film having a thermal conductivity lower than that of the substrate. Basic.

As shown in FIG. 1, the corrosion-resistant member of the present invention has a peritoneum 3 formed on at least one surface of a heat-resistant substrate 1. The heat-resistant substrate 1 can be provided with a heat generating layer 2 inside.
FIG. 2 shows a basic structure of a semiconductor manufacturing heater incorporating the corrosion-resistant member shown in FIG. The support member 4 supports the corrosion-resistant member, and an object to be processed (not shown) made of, for example, a silicon wafer is placed on the heat-resistant substrate 1 and is adsorbed and heated. Reference numeral 6 denotes an energization electrode to a coil for heat generation or electrostatic chuck. In this case, a problem such as cracking has been apt to occur in the column curved portion 5 (FIG. 3) of the column 4 in the past. By measuring the temperature in the column curved portion 5, the coating of the present invention The effect of the film can be confirmed.

The corrosion-resistant member of the present invention is a corrosion-resistant member comprising a heat-resistant substrate and a coating film made of aluminum nitride having a relative density of 50 or more and less than 98% and a thermal conductivity of 90 W / m · K or less. It is possible to suppress the conduction of heat from the surroundings to the surroundings, and to prevent cracking or breakage of surrounding members due to thermal stress.
As a heat-resistant substrate having functions of a heater and an electrostatic chuck, aluminum nitride having a high thermal conductivity is the mainstream. When aluminum nitride is used for the heat resistant substrate, the thermal conductivity of the coating film needs to be lower than that of the heat resistant substrate. Therefore, 90 W / m · of aluminum nitride sintered body (MAN-90 manufactured by Mitsui Mining Materials) It is preferable that it is K or less. Furthermore, in order to suppress heat conduction to the surroundings, it is more preferable to set it to 45 W / m · K or less. (Claim 2)

  The relative density of the coating film has a correlation with the thermal conductivity. When the relative density is high, the coating film is higher than the thermal conductivity of the base material (for example, a sintered body), and the heat insulating property to the surrounding members. Does not have. On the other hand, when the relative density is low, it is not formed as a film and peeled off from the substrate. Therefore, the relative density is preferably 50 or more and less than 98%. More preferably, it is 50 or more and less than 80% (Claim 3).

  By using aluminum nitride for the coating film, since it shows high corrosion resistance against the halogen-based gas and halogen plasma, deterioration of the base material and generation of particles can be suppressed. Furthermore, aluminum nitride formed by chemical vapor deposition using aluminum organometallic compounds or aluminum chloride and ammonia as raw materials does not contain any auxiliary agent such as a sintered body, and therefore generates less particles. . (Claim 4)

  The base material of the heat-resistant member is pyrolytic boron nitride, mixed sintered body of boron nitride and aluminum nitride, aluminum nitride, rare earth oxide, aluminum oxide, silicon oxide, zirconia, sialon, graphite, refractory metal It can fully cope with a high temperature process of 500 ° C. or higher.

  In particular, since the heat-resistant substrate 3 having a heater function is used in a high-temperature process, surrounding members that hold the heat-resistant substrate also have a high temperature. By providing the coating film of the present invention, even if the temperature of the heat-resistant substrate is increased by the heater function, it is possible to suppress heat conduction to the surroundings by the coating film. Furthermore, the coating film acts as a heat insulating action, and the temperature of the heat resistant substrate can be increased efficiently, leading to an energy saving effect.

[Example 1]
An aluminum nitride coating film was provided on one side of a φ200 × 5 t heat-resistant substrate provided with a heat generating layer inside by a thermal CVD method.
When forming the coating film, trimethylaluminum was supplied as a raw material by using a bubbler method as an organometallic compound of aluminum, and Ar gas was used as a gas for bubbling. Similar results are obtained using N ₂ , H ₂ , He, or the like.
Trimethylaluminum was placed in a thermostatic bath so as to be constant at 35 ° C., the bubbling Ar flow rate was 2 L / min, and the pressure in the cylinder was controlled to 10 kPa. In this case, the supply amount of trimethylaluminum is 0.3 mol / hr. On the other hand, ammonia was supplied by adjusting the mass flow controller so that the liquid was directly vaporized by heating to a supply amount of 1.7 mol / hr.

In order to introduce the raw material gas into the reactor, ammonia was supplied from the outside of the double tube and trimethylaluminum was supplied from the inside of the double tube.
The inside of the reaction furnace was evacuated with a vacuum pump so as to be in a vacuum state, and then the pressure was adjusted to about 50 Pa while continuing the evacuation.
The reaction temperature was changed between 600 ° C. and 1400 ° C., and a corrosion-resistant member (FIG. 1) provided with a coating film having a thickness of 100 μm made of aluminum nitride with adjusted thermal conductivity and relative density was produced. .

The physical properties of the coating film were measured by the following method.
The thermal conductivity was measured at room temperature (24 ° C.) by a periodic heating thermoreflectance method using a thermophysical microscope TM3 manufactured by BETHEL.
The relative density was calculated by measuring the film thickness and the weight before and after the film formation, taking the difference as the film weight, and the density at a relative density of 100% as 3.25 g / cm ³ .
Table 1 shows the relative density and thermal conductivity between the coating film and the substrate.

The corrosion-resistant member of FIG. 1 was incorporated in the structure shown in FIG. 2, and a temperature increase test was performed in a vacuum chamber. 3 kW of electric power was applied to the heat generation layer, and the temperature of the supporting column curved portion 5 shown in FIG. 3 when the steady state was reached was measured with a radiation thermometer. Further, as a comparative example, the temperature was similarly measured when no coating film was provided. Alumina was used as a support member, and after repeated heating and cooling 10 times, the state of the support bend 5 was observed.
Table 2 shows the results of the measurement temperature of the support column music part.

  As can be seen from the results shown in Table 2, by providing the heat resistant base material with an aluminum nitride coating film having a thermal conductivity of 90 W / m · K or less as in the present invention, the temperature of the column bending portion can be lowered. Can do. Thereby, the thermal stress which generate | occur | produces in a curved part is suppressed, it is in a favorable state after temperature rising, and generation | occurrence | production of the crack etc. is not recognized on the surface.

  As described above, the corrosion-resistant member of the present invention can suppress cracking and breakage due to thermal stress in curved portions and details by suppressing heat conduction at the film portion covered with the base material. Furthermore, since aluminum nitride has high corrosion resistance, it can be used for a long time even in a highly corrosive atmosphere.

DESCRIPTION OF SYMBOLS 1 Heat-resistant base material 2 Heat generating layer 3 Coating film 4 support | pillar 5 support | curve bending part (temperature measurement part)
6 Conductive electrodes

Claims (6)

  A corrosion-resistant member exposed to a plasma environment, wherein the entire surface or at least a part of the heat-resistant substrate is covered with a coating film having high corrosion resistance, and has a thermal conductivity lower than that of the heat-resistant substrate. A corrosion-resistant member characterized by being a coating film.   The corrosion resistance member according to claim 1, wherein the film has a thermal conductivity of 90 W / m · K or less.   The corrosion-resistant member according to claim 2, wherein the relative density of the film is 50% or more and less than 98%.   The corrosion-resistant member according to claim 3, wherein the film is made of AlN and is made using TMA (trimethylaluminum) gas and ammonia gas as raw materials.   The heat-resistant substrate is pyrolytic boron nitride, mixed sintered body of boron nitride and aluminum nitride, pyrolytic boron nitride coated graphite, aluminum nitride, rare earth oxide, aluminum oxide, silicon oxide, zirconia, sialon, graphite, high melting point The corrosion-resistant member according to claim 4, wherein any one of metals is a main component.   The corrosion resistant member according to claim 5, wherein the heat resistant substrate has a function of a heater and / or an electrostatic chuck.

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