JPH03115183A - Refractory material - Google Patents

Abstract

PURPOSE:To inhibit peeling by lowering the concn. of SiC in a composite film as the distance from the surface of a heat resistant base material is made greater and increasing the concn. of Si3N4 as the distance from the surface of the heat resistant base material is made greater. CONSTITUTION:The heat resistant base material such as carbon base material is heated at the prescribed temp. in a heat-treatment furnace. Carrier gas such as H2, gas for an Si source such as SiCl4 and gas for a carbon source such as propylene are supplied at a prescribed rate. Thereby an SiC film having proper thickness is formed on the surface of the carbon base material. Then NH3 is supplied as gas for a nitrogen source at the prescribed rate together with H2, SiCl4 and propylene. The composite layer of SiC and Si3N4 having proper thickness is formed. The SiC layer of 100mol.% concn. is formed in the part adjacent to the heat resistant base material and the composite layer of SiC and Si3N4 is formed as the distance is made farther therefrom. Furthermore H2, SiCl4 and NH3 are firstly supplied at the same rate. The composite layer of SiC and Si3N4 and an Si3N4 layer having 100mol% concn. are additionally formed. As a result, such a refractory member is obtained that the concn. of SiC in the composite film is lowered as a whole as the distance from the heat resistant base material is enlarged and also the concn. of Si3N4 is increased as the distance therefrom is enlarged.

Description

[Detailed Description of the Invention] +1) Purpose of the Invention [Field of Industrial Application] The present invention relates to a refractory material suitable as a material for forming susceptors, furnace core tubes, jigs, etc. used in semiconductor manufacturing. In particular, the present invention relates to a refractory material formed by adhering silicon carbide and silicon nitride to the surface of a heat-resistant base material to form a composite coating thereof.

[Prior Art] Conventionally, this type of refractory material has been produced by alternately depositing silicon carbide layers and silicon nitride layers on the surface of a heat-resistant base material such as carbon or silicon carbide by chemical vapor deposition or the like. When processing parts for semiconductor products (such as susceptors, furnace core tubes, or jigs) are created by forming a silicon composite film to close the pores of a heat-resistant base material, impurities that have entered the pores (for example, cleaning gas ) has been proposed to avoid contamination of semiconductor products by leaching out and diffusing into the heat treatment furnace during heat treatment of semiconductor products (for example, see Japanese Patent Publication No. 5O-4S154).

[Problems to be solved] However, in conventional refractory materials, a silicon carbide layer and a silicon nitride layer are deposited alternately to form a composite film of silicon carbide and silicon nitride. By controlling the thickness of each layer, it prevents the coarsening of crystal grains and suppresses the formation of pinholes due to erosion by cleaning gas, and secures the thickness of the composite coating to prevent thermal stress. Although the purpose of suppressing the occurrence of cracks was achieved, (i) due to the large difference between the coefficient of thermal expansion of the silicon carbide layer and the coefficient of thermal expansion of the silicon nitride layer, The disadvantage is that the layers can peel off from each other in a short period of time.
Furthermore, there was a drawback that the lifespan of (iil) could not be extended.

Therefore, the present invention aims to eliminate these drawbacks by producing silicon carbide and silicon carbide, in which the concentration of silicon carbide decreases and the concentration of silicon nitride increases as the distance from the surface of the heat-resistant base material increases. It is an object of the present invention to provide a fire-resistant material formed by forming a composite film of silicon nitride on the surface of a heat-resistant base material.

(2) Structure of the invention [Means for solving problems] The solution to the problem provided by the present invention is as follows.

"In a fire-resistant material formed by depositing silicon carbide and silicon nitride on a heat-resistant base material to form a composite film of silicon carbide and silicon nitride, the concentration of silicon carbide in the composite film varies depending on the distance from the surface of the heat-resistant base material. , and the concentration of silicon nitride in the composite film increases as the distance from the surface of the heat-resistant base material increases.

[Function] As specified in [Means for solving problems], in the fireproof material according to the present invention, the concentration of silicon carbide decreases and the concentration of silicon nitride increases as the distance from the surface of the heat-resistant base material increases. Since a composite film of silicon carbide and silicon nitride is formed on the surface of a heat-resistant base material, (i) the coefficient of thermal expansion in the composite film changes depending on the distance from the surface of the heat-resistant base material; At the very least, it has the effect of suppressing the occurrence of peeling, and also (ii) has the effect of ensuring film thickness while suppressing the coarsening of particles in the composite film, and (iii) suppresses erosion by cleaning gas. It has the effect of preventing the generation of pinholes, and also has the effect of suppressing the generation of cracks by being able to cope with thermal stress, and as a result (V) has the effect of extending the life.

[Example 1] Next, a preferred example of the fireproof material according to the present invention will be specifically described with reference to the accompanying drawings. However, the examples described below are described to facilitate or accelerate understanding of the present invention, and are not described to limit the present invention. In other words, each member disclosed in the embodiments described below includes all design changes and equivalent replacements that fall within the spirit and technical scope of the present invention.

FIG. 1 is a cross-sectional view showing one embodiment of the refractory material according to the present invention.

FIG. 2 is a graph showing changes in silicon carbide concentration in the embodiment shown in FIG.

FIG. 3 is a graph showing changes in silicon nitride concentration in the example of FIG. 1.

Yu! First, the structure of an embodiment of the fireproof material according to the present invention will be described in detail with reference to FIG.

(2) is a refractory material according to the present invention, which is suitable as a material for making susceptors, furnace core tubes, jigs, etc. used in semiconductor manufacturing;
1 and is formed on the surface of the heat-resistant base material 11 by chemical vapor deposition, etc., and has an appropriate film thickness (for example, 50 to 2000 μm).
Composite coating 12 of silicon carbide and silicon nitride with
It is equipped with

As the heat-resistant base material 11, a base material to which silicon carbide is easily attached by chemical vapor deposition or the like is suitable, such as a carbon base material, a silicon carbide base material, or a silicon-containing silicon carbide base material.

In composite coating 12, as the distance from the surface of heat-resistant base material 11 increases, the concentration of silicon carbide decreases and the concentration of silicon nitride increases. At this time, the concentration of silicon carbide in the region adjacent to the heat-resistant base material 11 of the composite coating 12 is 100.
It is preferable that the silicon nitride concentration be 100 mol % on the outer surface of the composite coating 12 because it can reduce the porosity.

The composite film 12 may be a single layer as a whole (
, or may have multiple layers.

Furthermore, with reference to FIG. 1, the action of an embodiment of the fireproof material according to the present invention will be explained in detail.

In the fire-resistant material according to the present invention, the composite film 12 of silicon carbide and silicon nitride formed on the surface of the heat-resistant base material 11 has silicon carbide in the vicinity of its inner surface (that is, the surface that contacts the heat-resistant base material 11). Since the concentration of silicon nitride is high and the concentration of silicon nitride is high on the outer surface, it easily adheres to the surface of the heat-resistant base material 11 and has excellent corrosion resistance from the outside.

Further, in the fire-resistant material according to the present invention, since the composite film 12 is continuously deposited while changing the concentration of silicon carbide and silicon nitride, (i) the coefficient of thermal expansion in the composite film 12 is lower than that of the heat-resistant base material. The peeling caused by the difference in thermal expansion coefficient between silicon carbide and silicon nitride is suppressed, and (ii) the coarsening of particles in the composite coating is suppressed. The film thickness is ensured, and (ii
i) Erosion caused by the cleaning gas is suppressed to prevent the formation of pinholes, and cracks are suppressed by being able to cope with (ivl thermal stress), resulting in an extension of (ivl life).

In addition, with reference to FIG. 1, a method for manufacturing the fireproof material according to the present invention will be briefly described.

The refractory material (1) according to the present invention is usually produced by chemical vapor deposition. That is, for fireproof materials according to the present invention,
The heat-resistant base material 11 is housed in a heat treatment furnace, and while maintaining its surface temperature at an appropriate temperature, an appropriate heat treatment gas is applied to the composite coating 1.
It is manufactured by supplying the film for a time corresponding to the film thickness of No. 2.

The heat treatment gas is a carrier gas (for example, H2 gas), a silicon source gas (for example, 5iC14 gas), a carbon source gas (for example, C, H, gas), and a nitrogen source gas (for example, NHm gas). It is adjusted by mixing at an appropriate mixing ratio that is changed in accordance with (that is, as the elapsed time increases, the silicon source gas decreases and the nitrogen source gas increases).

The refractory material according to the present invention will be described in detail by citing specific numerical values.

As the heat-resistant base material, a carbon base material having a coefficient of thermal expansion of 4.2 Xl0-' was used.

The heat-resistant base material is inserted into a heat treatment furnace and the surface temperature is increased to 130°C.
The temperature was maintained at 0°C. In this state, the heat treatment furnace contains H2 gas as a carrier gas and 5iC1 as a silicon source gas.
4 gas and C5Ha gas as a carbon source gas at 0.54/min, 1.0127 min, and 0.212/min, respectively.
was fed over a period of 10 minutes at a feed rate of 10 minutes. As a result, a silicon carbide layer with a thickness of 10 μm was formed on the surface of the heat-resistant base material.

Next, while supplying H2 gas, 5iC14 gas, and C5Hs gas at the above-mentioned supply rates, NH gas as a nitrogen source was supplied to the heat treatment furnace at a rate of 0.08 J2/min.
Additional feeds were provided over a period of minutes. As a result, a composite layer of silicon carbide and silicon nitride with a film thickness of 90 μm is additionally formed on the silicon carbide layer, and as a whole, the concentration of silicon carbide is 100 mol% in the range of 10 μm from the surface of the heat-resistant base material.
A composite film was formed in which the silicon carbide concentration and the silicon nitride concentration were both 50 mol % in the range of 10 to 90 μm.

Finally, H gas, 5iC14 gas, and NHs gas were supplied to the heat treatment furnace for 10 minutes at the above-mentioned supply ratios. As a result, a silicon nitride layer with a film thickness of 10 μm is additionally formed on the composite layer of silicon carbide and silicon nitride, and the overall concentration of silicon carbide is 100 mol% in the range of 10 μm from the surface of the heat-resistant base material. Te10~9
A composite film was formed in which the silicon carbide concentration and the silicon nitride concentration were both 50 mol % in the 0 μm range, and the silicon nitride concentration was 100 mol % in the 90 to 100 μm range.

As a result of the above, the concentration distribution of silicon carbide and the concentration distribution of silicon nitride are as shown by the broken lines in FIGS. 2 and 3, and a composite film of silicon carbide and silicon nitride with a film thickness of 100 μm is formed on the surface of the heat-resistant base material. The fire-resistant material according to the present invention was formed against the above.

When the refractory material according to the present invention was used as a susceptor in an epitaxial manufacturing device for manufacturing epitaxial wafers, no pinholes or cracks were observed even after 250 uses, and no impurities were observed in the manufactured epitaxial wafers. No increase in concentration was observed.

As the heat-resistant base material, a carbon base material having a coefficient of thermal expansion of 4.2 Xl0-' was used.

The heat-resistant base material is inserted into a heat treatment furnace and the surface temperature is increased to 130°C.
The temperature was maintained at 0°C. In this state, the heat treatment furnace contains H gas as a carrier gas and 5iC1 gas as a silicon source gas.
4 gas and CaH- gas as a carbon source gas at 0.512/min, respectively.1. O127 min and 0.212
It was fed over a 10 minute period at a feed rate of 7 minutes. As a result, a silicon carbide layer with a thickness of 10 μm was formed on the surface of the heat-resistant base material.

Next, H, gas and 5iC14 gas were supplied at the above-mentioned supply ratio, and while the supply ratio of C5Ha gas was gradually reduced, the supply ratio of NH, gas as a nitrogen source to the heat treatment furnace was 0.01. The feed rate was increased gradually over a period of 90 minutes to a feed rate of 1/min. As a result, a composite layer of silicon carbide and silicon nitride with a film thickness of 90 μm is additionally formed on the silicon carbide layer, and the overall concentration of silicon carbide is 100 mol% in the range of 10 μm from the surface of the heat-resistant base material. te10
A composite film was formed in which the silicon carbide concentration gradually decreased from 100 mol% to 0 mol% and the silicon nitride concentration gradually increased from 0 mol% to 100 mol% in the range of ~90 μm.

Finally, H8 gas, 5iC14 gas and NHI gas are
0.52/min, 1.0β/min and 0.08β respectively
was fed to the heat treatment furnace for 10 minutes at a feed rate of 1/min. As a result, a silicon nitride layer with a film thickness of 10 μm is additionally formed on the composite layer of silicon carbide and silicon nitride, and the overall concentration of silicon carbide is 100 mol% in the range of 10 μm from the surface of the heat-resistant base material. Te10-90
In the μm range, the concentration of silicon carbide gradually decreases from 100 mol% to 0 mol%, and the concentration of silicon nitride gradually increases from 0 mol% to 100 mol%, and 90-100 mol%.
A composite film with a silicon nitride concentration of 100 mol % in the micrometer range was formed.

As a result, the silicon carbide concentration distribution and the silicon nitride concentration distribution are as shown by the solid lines in FIGS. 2 and 3, and the composite coating of silicon carbide and silicon nitride with a thickness of 100 μm is formed on the surface of the heat-resistant base material. The fire-resistant material according to the present invention was formed against the above.

When the refractory material according to the present invention was used as a susceptor in an epitaxial manufacturing device for manufacturing epitaxial wafers, no pinholes or cracks were observed even after 250 uses, and no impurities were observed in the manufactured epitaxial wafers. No increase in concentration was observed.

! As the blood plate and the heat-resistant base material, a silicon carbide base material having a thermal expansion coefficient of 4.5 Xl0-' was used.

The heat-resistant base material is inserted into a heat treatment furnace and the surface temperature is increased to 130°C.
The temperature was maintained at 0°C. In this state, the heat treatment furnace contains H2 gas as a carrier gas and 5iC1 as a silicon source gas.
4 gas and C, H, and gases as carbon source gases at 0.5 ff7 min, 1.012/min, and 0.2β, respectively.
was fed over a period of 10 minutes at a feed rate of /min. As a result, a silicon carbide layer with a thickness of 10 μm was formed on the surface of the heat-resistant base material.

Next, while supplying H2 gas, 5iC14 gas, and C5Hs gas at the above-mentioned supply rates, NHs gas as a nitrogen source was additionally supplied to the heat treatment furnace at a rate of 0.01/min for 90 minutes. As a result, a composite layer of silicon carbide and silicon nitride with a film thickness of 90 μm is additionally formed on the silicon carbide layer, and as a whole, a composite layer of silicon carbide and silicon nitride is formed from the surface of the heat-resistant base material.
A composite film was formed in which the concentration of silicon carbide was 100 mol% in the range up to 0 μm, and the concentration of silicon carbide and silicon nitride were both 50 mol% in the range of 10 to 90 μm.

Finally, H2 gas, 5iC14 gas and NHs gas are
The feed rate described above was fed to the heat treatment furnace for 10 minutes. As a result, a silicon nitride layer with a film thickness of 10 μm is additionally formed on the composite layer of silicon carbide and silicon nitride, and the overall concentration of silicon carbide is 100 mol% in the range of 10 μm from the surface of the heat-resistant base material. Te10-90
A composite film was formed in which the silicon carbide concentration and the silicon nitride concentration were both 50 mol % in the μm range, and the silicon nitride concentration was 100 mol % in the 90 to 100 μm range.

As a result of the above, the concentration distribution of silicon carbide and the concentration distribution of silicon nitride are as indicated by the broken lines in FIGS. 2 and 3, and a composite coating of silicon carbide and silicon nitride with a thickness of 1001 m is formed on the surface of the heat-resistant base material. The fire-resistant material according to the present invention was formed against the above.

When the refractory material according to the present invention was used as a susceptor in an epitaxial manufacturing device for manufacturing epitaxial wafers, no pinholes or cracks were observed even after 250 uses, and no impurities were observed in the manufactured epitaxial wafers. No increase in concentration was observed.

! Amount A: As a heat-resistant base material, the coefficient of thermal expansion is 4. A silicon-containing silicon carbide base material OXl0-' was employed.

The heat-resistant base material is inserted into a heat treatment furnace and the surface temperature is increased to 130°C.
The temperature was maintained at 0°C. In this state, the heat treatment furnace contains H2 gas as a carrier gas and 5iC1 as a silicon source gas.
+ gas and C5Ha gas as carbon source gas are 0.512/min, 1.012/min and 0.212, respectively.
It was fed over a 10 minute period at a feed rate of 7 minutes. As a result, a silicon carbide layer with a thickness of 10 μm was formed on the surface of the heat-resistant base material.

Next, while supplying H2 gas and 5iC1n gas at the above supply ratio and gradually reducing the supply ratio of C3HII gas, the supply ratio of NH and gas as a nitrogen source to the heat treatment furnace was set to 0.0812. The feed rate was increased gradually over a period of 90 minutes to a feed rate of 1/min. As a result, a composite layer of silicon carbide and silicon nitride with a film thickness of 90 μm is additionally formed on the silicon carbide layer, and as a whole, a composite layer of silicon carbide and silicon nitride is formed from the surface of the heat-resistant base material.
The concentration of silicon carbide is 100 mol% in the range of 0 μm, and the concentration of silicon carbide gradually decreases from 100 mol% to 0 mol% in the range of 10 to 90 μm, and the concentration of silicon nitride is from 0 mol% to 100 mol%. Composite coatings were formed with gradually increasing mole %.

Finally, H2 gas, 5IC14 gas, and NH gas are
0.5127 minutes, 1.0127 minutes and 0.0 respectively
A feed rate of 8 I2/min was fed to the heat treatment furnace for 10 minutes. As a result, a silicon nitride layer with a film thickness of 10 μm is additionally formed on the composite layer of silicon carbide and silicon nitride, and the concentration of silicon carbide (100 mol% There is one
In the range of 0 to 90 μm, the concentration of silicon carbide gradually decreases from 100 mol% to 0 mol%, and the concentration of silicon nitride gradually increases from 0 mol% to 100 mol%, and 90 mol%.
A composite film with a silicon nitride concentration of 100 mol % was formed in the range of ~100 μm.

As a result, the silicon carbide concentration distribution and the silicon nitride concentration distribution are as shown by the solid lines in FIGS. 2 and 3, and the composite coating of silicon carbide and silicon nitride with a thickness of 100 μm is formed on the surface of the heat-resistant base material. The fire-resistant material according to the present invention was formed against the above.

When the refractory material according to the present invention was used as a susceptor in an epitaxial manufacturing device for manufacturing epitaxial wafers, no pinholes or cracks were observed even after 250 uses, and no impurities were observed in the manufactured epitaxial wafers. No increase in concentration was observed.

A carbon base material having a thermal expansion coefficient of 4.2 Xl0-' was used as the medically heat-resistant base material.

The heat-resistant base material is inserted into a heat treatment furnace and the surface temperature is increased to 130°C.
The temperature was maintained at 0°C. In this state, the heat treatment furnace contains H gas as a carrier gas and 5iC1 gas as a silicon source gas.
4 gas and CJa gas as a carbon source gas, each at a rate of 0.5β/min, 1. O was fed over 100 minutes at a feed rate of 127 minutes and 0.2 β/minute.

As a result, a silicon carbide film having a thickness of 100 μm was formed on the surface of the heat-resistant base material, and a fire-resistant material was obtained.

When the refractory material was used as a susceptor in an epitaxial manufacturing apparatus for manufacturing epitaxial wafers, pinholes were generated after 72 uses, making it unusable.

Comparison 1 As a heat-resistant base material, the coefficient of thermal expansion is 4. A silicon-containing silicon carbide base material of OX10-'' was used.

The heat-resistant base material is inserted into a heat treatment furnace and the surface temperature is increased to 130°C.
The temperature was maintained at 0°C. In this state, the heat treatment furnace contains H2 gas as a carrier gas and 5iC1 as a silicon source gas.
4 gas and C, H, and gases as carbon source gases each at 0.5β/min, 1. O127 min and 0.2127
100 minutes.

As a result, a silicon carbide film having a thickness of 100 μm was formed on the surface of the heat-resistant base material, and a fire-resistant material was obtained.

When the refractory material was used as a susceptor in an epitaxial manufacturing apparatus for manufacturing epitaxial wafers, pinholes were generated after 65 uses, making it unusable.

(3) Effects of the invention As is clear from the above (the fireproof material according to the present invention has
A composite film of silicon carbide and silicon nitride is formed on the surface of the heat-resistant base material, in which the concentration of silicon carbide decreases and the concentration of silicon nitride increases as the distance from the surface of the heat-resistant base material increases. (i) The coefficient of thermal expansion in the composite coating can be changed depending on the distance from the surface of the heat-resistant base material to suppress peeling, and (ii) It has the effect of suppressing the coarsening of particles and ensuring a suspended film thickness, and (iii) it also has the effect of suppressing erosion by cleaning gas and preventing the generation of pinholes, and (iv) it is resistant to thermal stress. It has the effect of suppressing the occurrence of cracks as much as possible, and as a result, it has the effect of extending the Vl life.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the refractory material according to the present invention, and FIGS. 2 and 3 are graphs for explaining the internal structure of the embodiment shown in FIG.

Claims (1)

[Claims] In a fire-resistant material formed by depositing silicon carbide and silicon nitride on a heat-resistant base material to form a composite film of silicon carbide and silicon nitride, the concentration of silicon carbide in the composite film varies depending on the distance from the surface of the heat-resistant base material. A fire-resistant material characterized in that the concentration of silicon nitride in the composite film decreases as the size increases, and the concentration of silicon nitride in the composite film increases as the distance from the surface of a heat-resistant base material increases.