JP2000160343A - Corrosion resistant cvd-silicon carbide and corrosion resistant cvd-silicon carbide coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the etching resistance to various gases and corrosion resistance to various metals, in the crystals composing β-SiC formed by a CVD method, by specifying the ratio of the (111) plane to be occupied. SOLUTION: A graphite substrate is coated with SiC by a CVD method, next, graphite is mechanically or chemically removed to form into dense CVD- SiC only, by which β-SiC as cubic crystals is obtd. At this time, by controlling the substance temp. at the time of CVD treatment to about 1300 deg.C, desirably to about >=1400 deg.C and controlling the CVD treating conditions, in the crystals composing the surface of β-SiC, the ratio of the crystals showing the crystal orientation in the (111) plane to be occupied is controlled to <=0.5 of the whole, desirably to <=0.4. In this way, CVD-SiC excellent in corrosion resistance to metals such as Al, Cr, Fe or the like or the alloys thereof and exhibiting etching resistance to the gases of HCl, ClF3 or the like can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epitaxial growth apparatus in a semiconductor manufacturing process and a chemical vapor deposition (Chemical Vapor Deposition) in which in-line cleaning is performed.
por Deposition (hereinafter, referred to as CVD)
Corrosion resistant CVD-SiC excellent in corrosion resistance to metal and cleaning gas used as a jig of the apparatus, and corrosion resistant CVD in which the substrate surface is coated with corrosion resistant CVD-SiC
The present invention relates to a SiC coating material.

[0002]

2. Description of the Related Art Conventionally, components, jigs and the like of various apparatuses in a semiconductor manufacturing process include SiC alone,
BACKGROUND ART A SiC coating material in which a substrate surface made of a carbonaceous material such as graphite or ceramics is coated with SiC is widely used.

For example, it is used as a jig for a silicon epitaxial growth apparatus 1 shown in FIG. The epitaxial growth apparatus 1 is an apparatus for growing a crystal on a surface of a silicon wafer 2 heated by an RF coil 5 or the like in a reaction chamber 4 so as to have the same crystal orientation. Here, as the susceptor 3 on which the silicon wafer 2 is mounted, a high-purity isotropic graphite whose surface is coated with CVD-SiC is widely used.

However, the SiC film may be unusable due to peeling or cracking of the SiC film due to repetitive thermal stress, or a defect such as a pinhole which is considered to be generated by a reaction with a metal that has entered for some reason.

In the semiconductor manufacturing process, in addition to the formation of the epitaxial growth film, a process of forming a polycrystalline Si film or the like on a wafer by various CVD devices is one of essential processes. At this time, the wafer is placed on a jig having at least a surface made of SiC, like the susceptor used in the above-described epitaxial growth apparatus. Therefore, a film of the same quality as the wafer is formed on the jig. Conventionally, the film adhered and formed on the jig has been washed and removed with an acid or alkali solution before a step of mounting a new wafer and forming a film.

[0006] However, in the conventional wet cleaning, the apparatus is once stopped, the jigs are taken out of the apparatus, washed outside the apparatus, washed, and reloaded into the apparatus each time the cleaning is performed. Further, since the cleaning is performed outside the apparatus, there is a problem that impurities are attached to the jig when the apparatus is moved in and out, and this not only adversely affects the product quality but also shortens the life of the jig itself.

Recently, in order to improve the above problem,
With the improvement of various CVD apparatuses and the development of cleaning techniques, dry cleaning with a chlorine fluoride gas such as ClF ₃ has been performed in the same reaction chamber of the CVD apparatus after forming a film, that is, inline.

[0008] It has been found that dry cleaning with chlorine fluoride gas such as ClF ₃ etches SiC on the jig surface which is not so etched by conventional wet cleaning. As a result, the SiC on the jig surface peels off and falls off,
The particles are scattered in the chamber of the CVD apparatus as particles and fall on the wafer, which is one of the causes of the defect of the wafer. In addition, the service life of the jig has been shortened, and a new problem has occurred which causes a reduction in yield and a reduction in production efficiency.

Also, the jigs used in these CVD apparatuses sometimes react with the metal that has entered for some reason to generate pinholes, which makes the jig unusable.

[0010]

Therefore, in the present invention,
Various metals, especially Al, Cr, Fe, Co, Ni, Cu or ClF, ClF ₃ , ClF ₅ , NF ₃ , HCl,
Β-Si having corrosion resistance to gases such as Cl ₂ and HF
It is an object of the present invention to provide C and a β-SiC coating material coated on the surface of a substrate with the same.

[0011]

Means for Solving the Problems The present inventors have found that the ratio of the (111) plane of β-SiC formed on the surface to the main crystal plane to be formed is 0.5 or less. To
ClF, Cl used for in-line cleaning
It has excellent etching resistance to gases such as F ₃ , ClF ₅ , NF ₃ , HCl, Cl ₂ , and HF.
The present invention has been found to have corrosion resistance to an alloy composed of one or more of metals such as l, Cr, Fe, Co, Ni, and Cu, and completed the present invention.

That is, the invention of claim 1 of the present invention provides
Corrosion resistant CVD-SiC in which the ratio of the (111) plane in the crystal constituting β-SiC formed by the VD method is 0.5 or less.

According to a second aspect of the present invention, there is provided a corrosion-resistant CVD-SiC wherein the ratio of the (111) plane occupying 0.5 or less in the crystal constituting β-SiC formed by the CVD method is as follows:
It is a corrosion-resistant CVD-SiC coating material coated on a substrate made of SiC or a carbonaceous material.

According to a third aspect of the present invention, there is provided a jig for a CVD apparatus for semiconductor production using the corrosion-resistant CVD-SiC coating material according to the second aspect.

In the present invention, SiC is obtained by adding CV to a graphite substrate.
A method in which SiC is coated by the method D, and then graphite is removed mechanically or chemically to obtain only dense CVD-SiC. Graphite material, SiC converted from graphite material, sintered SiC, and CVD -Any of SiC coated and formed on the surface of a substrate made of SiC by a CVD method may be used. Here, the SiC converted from the graphite material is a so-called CVR-SiC obtained by reacting the graphite material with a silicate gas to convert the graphite material into SiC.
iC is obtained by adding a sintering aid to SiC powder and sintering at a high temperature of 1600 ° C. or higher.

Further, the SiC formed by the CVD method is an emergency formed by a nucleus of SiC generated from a source gas at the time of a CVD process being deposited on the surface of a base material and growing the deposited nucleus. It is a dense film. In addition, SiC
There are two types of α-type, hexagonal, and β-type, cubic. In the CVD method according to the present invention, β-type SiC is generated.

The ratio of the crystal having the crystal orientation in the (111) plane direction to the crystal constituting the surface of β-SiC by the CVD method is 0.5 or less, preferably 0.4 or less.
The following is assumed. If it is larger than 0.5, it is considered that the orientation of the same plane becomes large, so that erosion between crystals or between crystal layers is likely to occur, and corrosion resistance to various metals or a cleaning gas is not exhibited. Here, the crystal planes targeted for this ratio are the (200) plane, the (220) plane, and the (311) plane having different orientations from the (111) plane. This ratio can be determined from (11) based on the result of X-ray diffraction.
1) The value obtained by dividing the peak intensity of the (111) plane by the sum of the peak intensities (peak heights) of the crystal planes having different orientations from the plane is adopted.

By adjusting the conditions of the CVD process, the ratio of the crystallites constituting the crystallite in the (111) plane direction can be reduced to 0.5 or less on the surface of β-SiC. The orientation of each constituent crystal becomes disordered. In comparison with β-SiC formed of crystallites grown only in the (111) plane direction, Al, Cr, Fe, Co,
It becomes excellent in corrosion resistance to an alloy composed of one or more of metals such as Ni and Cu. Further, ClF, ClF ₃ , ClF ₅ , NF ₃ , HCl, C
It is presumed that any one of l ₂ and HF or any one of them is diluted with an inert gas to exhibit etching resistance to a mixed gas. Among them, HCl and ClF ₃ gas exhibit excellent etching resistance.

The (200), (220), and (311) planes, which are crystal planes different from the (111) plane, have a CV orientation.
Among the control factors such as substrate, substrate temperature, raw material gas, furnace pressure, raw material gas concentration at the time of D processing, the temperature is particularly affected, and becomes more remarkable as the substrate temperature at the time of CVD processing becomes higher. . Therefore, the ratio occupied by the (111) plane is 0.5
Or less, preferably 0.4 or less, the substrate temperature at the time of CVD treatment is at least 1300 ° C., preferably 1
400 ° C. or higher.

As described above, the β-SiC formed on the surface of a CVD-SiC coating material in which SiC is coated on the surface of a base material of a carbonaceous material such as graphite or graphite or a ceramic such as SiC by a CVD method. Among the crystals that constitute SiC,
By setting the ratio of the (111) plane to 0.5 or less,
It has corrosion resistance to metal. This allows
It can be used as a jig for a CVD device for manufacturing various semiconductors. That is, by forming the CVD-SiC according to the present invention on the surface of the jig, the occurrence of pinholes and the like can be suppressed, and the useful life can be extended.

As a CVD apparatus for manufacturing a semiconductor, for example, an epitaxial growth apparatus, or dry cleaning using chlorine fluoride gas or the like, that is, in-line cleaning is performed to improve yield and production efficiency.
There are a CVD apparatus, an RTPCVD apparatus, and the like. These Si
The present invention can be applied as a jig such as a susceptor for mounting a wafer. Each of these has one or more reaction chambers, and the in-line cleaning is performed in the same reaction chamber.

FIG. 6 is a schematic sectional view of a reaction chamber of the LPCVD apparatus. LPPress is an LPCVD system.
It is an abbreviation of re CVD device, and as shown in the figure, it is composed of a SiC boat 13 on which a wafer 14 is placed and a SiC soaking tube 12, and a CVD process is performed under reduced pressure. 14 is used for forming or diffusing a polycrystalline silicon film or a silicon nitride film. Here, the jig according to the present invention is the boat 13 and the soaking tube 12.

FIG. 7 is a schematic sectional view of a reaction chamber of an RTPCVD apparatus. RTPCVD equipment means Rapid T
It is an abbreviation of a thermal processing CVD apparatus, and as shown in FIG.
C susceptor 22 and S on which susceptor 22 is placed
and a jig 24 made of iC, which is heated by a halogen lamp and heated by local heating such as oxidation or CVD.
Which is used for forming a polycrystalline silicon film or a silicon nitride film. Here, the jig according to the present invention includes the susceptor 22 and the jig 24 made of SiC on which the susceptor 22 is mounted.

As described above, the CVD-S
iC or CVD-SiC coating material is CV for semiconductor manufacturing
It can be applied as a jig for the D device. In addition to the jig for the CVD apparatus for semiconductor production, it can be used as a jig for a single crystal pulling apparatus by utilizing its excellent corrosion resistance.

Hereinafter, the present invention will be described specifically with reference to examples.

[0026]

EXAMPLES (Example 1) A bulk density of 1.85 g /
cm ³ of isotropic graphite material (manufactured by Toyo Tanso Co., Ltd.)
It was processed to 20 × 20 × 5 mm. Next, these are set in a CVD apparatus, and SiCl ₄ + C ₃ H ₈ is used as a raw material gas, the furnace pressure is 250 Torr, and the substrate temperature is 1400 ° C.
VD processing was performed, and the entire surface was coated with SiC.

After coating with CVD-SiC, the surface is
X-ray diffraction analysis was performed using a tube of No. FIG. 1 shows the results of the analysis. Β-SiC (111) described in the figure
Etc. represent each crystal plane. Next, of the crystals constituting the surface, the ratio occupied by the (111) plane is (111)
It was calculated by the following equation using the intensity ratio of each crystal plane having a different crystal orientation from the crystal plane (the height of the peak representing each crystal plane). That is, the ratio = (111) / ((111) + (200) + (220) + (311)). Among the constituent crystallites of SiC whose surface is covered, (1
11) The ratio occupied by the plane was 0.32.

(Example 2) After processing a base material of the same quality as in Example 1 into the same shape, using the same CVD apparatus as in Example 1, using SiCl ₄ + C ₃ H ₈ as a raw material gas, 250
CVD treatment was performed at Torr and a substrate temperature of 1300 ° C., and the entire surface was coated with SiC. Thereafter, in the same manner as in Example 1, X-ray diffraction analysis was performed on the surface coated with SiC.
FIG. 2 shows the result of the X-ray diffraction. From this result, the ratio of the (111) plane occupied by the constituent crystallites of the SiC covering the surface was determined in the same manner as in Example 1.
It was 0.

(Example 3) 1.85 g of bulk density as a substrate
/ Isotropic graphite material cm ³ using (manufactured by Toyo Tanso Co.) was processed into 20 × 20 × 5 mm as in Example 1 the same shape. These are placed together with metal Si in a CVD apparatus, the furnace temperature is heated to 1800 ° C., carbon dioxide gas is introduced into the furnace, and the sublimation gas of metal Si reacts with carbon dioxide gas to form SiC on the substrate surface. Was deposited. Thereafter, in the same manner as in Example 1, X-ray diffraction analysis was performed on the surface coated with SiC. FIG. 3 shows the result of the X-ray diffraction. From this result, the ratio of the (111) plane occupied by the constituent crystallites of the SiC covering the surface was determined in the same manner as in Example 1.
0.36.

(Comparative Example 1) After processing a base material of the same quality as in Example 1 into the same shape, using the same CVD apparatus as in Example 1, using SiCl ₄ + C ₃ H ₈ as the raw material gas, 250
A CVD process was performed at Torr and a substrate temperature of 1200 ° C., and the entire surface was coated with SiC. Thereafter, in the same manner as in Example 1, X-ray diffraction analysis was performed on the surface coated with SiC.
FIG. 4 shows the result of the X-ray diffraction. From this result, as in Example 1, the ratio of the (111) plane to the constituent crystallites of SiC whose surface was covered was 1.0.

Examples 1 and 2 and Comparative Example 1 differ only in the substrate temperature during the CVD process, and all the other processing conditions are the same. As the base material temperature increases, the proportion of the (111) plane in the crystals constituting the surface decreases. In other words, it can be said that as the temperature of the base material increases, the direction in which SiC precipitates and grows becomes multi-directional, and the crystals constituting the surface become disordered.

In order to examine the etching resistance to the gas used for in-line cleaning of the samples of Examples 1 to 3 and Comparative Example 1, each sample was treated with ClF ₃ , 1 at 800 ° C.
Each was exposed to HCl at 100 ° C. for 60 minutes, and the etching resistance was examined.

Table 1 shows the etching resistance of each sample to each gas.

[0034]

[Table 1]

In order to examine the reactivity of the samples of Example 1 and Comparative Example 1 with metals, each sample was prepared so that the film thickness and surface roughness did not affect the reaction with various metals. The film thickness was 105 μm, and the surface of each sample was polished under the same conditions. A metal powder having a purity of 99% or more and a particle size of 40 μm is placed on the polished surface.
After heating to 300 ° C., the reactivity with the metal was examined. In addition,
The reactivity was observed by an electron microscope, and the cross section of each sample was evaluated by performing X-ray line analysis from the outer surface side toward the inside.

Table 2 shows the degree of reaction of the sample of Example 1 and Table 3 of the sample of Comparative Example 1 with each metal at each temperature. The degree of reaction was evaluated on a three-point scale. In the table, ○ indicates that a reaction was observed only in the surface layer, Δ indicates that a reaction was observed all the way into the film, and X indicates that a violent reaction reaching the substrate was observed.

[0037]

[Table 2]

[0038]

[Table 3]

As shown in Table 1, by increasing the substrate temperature during the CVD process, the growth direction of
1) It can be seen that the resistance to the etching gas used for in-line cleaning is improved by growing not only the surface direction but also the other surface.

From Tables 2 and 3, it can be seen that Example 1 has a higher reaction start temperature with each metal than the sample of Comparative Example 1.

[0041]

According to the present invention, at least the surface is β-
Of the crystals formed of SiC and constituting the surface, (1
11) When the ratio occupied by the surface is 0.5 or less, it exhibits etching resistance to various gases used for in-line cleaning in an LPCVD apparatus, an RTPCVD apparatus, and a CVD apparatus for epitaxial growth,
In addition, it has corrosion resistance to various metals,
It can contribute to improvement of production efficiency and yield in semiconductor manufacturing.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction result of SiC subjected to a CVD process at 1400 ° C.

FIG. 2 is an X-ray diffraction result of SiC subjected to a CVD process at 1300 ° C.

FIG. 3 is an X-ray diffraction result of SiC coated on the surface by a reaction between a sublimation gas of Si and a carbon dioxide gas.

FIG. 4 is an X-ray diffraction result of SiC subjected to a CVD process at 1200 ° C.

FIG. 5 is a schematic sectional view of an epitaxial growth apparatus.

FIG. 6 is a schematic sectional view of an LPCVD apparatus.

FIG. 7 is a schematic sectional view of an RTPCVD apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 epitaxial growth apparatus 2 silicon wafer 3 susceptor 4 reaction chamber 5 RF coil 11 LPCVD apparatus reaction chamber 12 soaking tube 13 board 14 wafer 21 RTPCVD apparatus reaction chamber 22 susceptor 23 wafer 24 jig

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H01L 21/68 H01L 21/68 N

Claims (3)

[Claims] 1. The ratio of the (111) plane occupying 0.5% of the crystal constituting β-SiC formed by CVD.
The following corrosion resistant CVD-SiC. 2. The ratio of the (111) plane occupying 0.5% of the crystal constituting β-SiC formed by the CVD method.
Corrosion resistant CVD-S obtained by coating the following corrosion resistant CVD-SiC on a substrate made of SiC or carbonaceous material
iC coating. 3. A jig for a CVD apparatus for semiconductor production using the corrosion-resistant CVD-SiC coating material according to claim 2.