JPH0397691A - Jig for producing semiconductor device - Google Patents

Abstract

PURPOSE:To improve quality by coating carbon graphite with a film which makes the surface thereof non-porous and coating the surface thereof with a polycrystalline film of SiC by a chemical vapor growth method. CONSTITUTION:Resin, such as phenol, having the compsn. of a CH system is applied on the surface of the porous carbon graphite 11 constituting a susceptor 21 from Fig. II expanding the part A of Fig. I to fill holes 13. The resin is subjected to a high-temp. treatment in an inert atmosphere and is thereby carbonized to change the compsn. to a glassy carbon film 15. The surface thereof is then coated with the polycrystalline film 12 of the SiC by the chemical vapor growth method. The epitaxial layer which obviates the exhalation of H2O, O2, etc., is thus obtd.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to improvements in jigs for manufacturing semiconductor devices, such as susceptors for epitaxial length equipment or wafer baskets for holding silicon wafers. The purpose of the jig is to provide a jig with a structure that has fewer adsorption sites where contaminants and the like can enter. Carbon graphite is coated with a film that makes its surface non-porous, and then chemically coated with a film that makes the surface non-porous. It includes a jig for manufacturing non-porous semiconductor devices obtained by coating a silicon carbide (SiC) polycrystalline film using a vapor phase process.

? INDUSTRIAL APPLICATION FIELD The present invention relates to improvements in semiconductor device manufacturing jigs, for example, jigs such as susceptors for epitaxial growth equipment or wafer baskets for holding silicon wafers. In recent manufacturing processes, there is a demand for jigs that contain low impurities and that incorporate little moisture and 0.

[Conventional technology]

For example, in a conventional Si epitaxial film manufacturing process, a silicon carbide (SiC) coated graphite susceptor was used. However, while performing processing such as loading a wafer (processed substrate) in the atmosphere, moisture in the atmosphere, 02, is absorbed.

FIG. 3 shows a cross section of the susceptor 21 on which the wafer 22 is placed. When the part surrounded by circle A in the diagram of this sucrose pig 21 was enlarged with a microscope, the condition shown in FIG. 2 was observed. In the figure, 11 is carbon graphite forming the susceptor 21, and 12 is a SiC polycrystalline film. To coat the susceptor 21 with SiC, the susceptor 2
SiC is deposited by chemical vapor deposition (CVD) method on carbon graphite 11 containing S
The iC polycrystalline film 12 is stretched in a polycrystalline state on the carbon graphite 11 as shown in the figure. Since carbon graphite itself is a porous material, pores 13 are created near its surface, and since SiC is a so-called bulky crystal, gaps 14 are created between SiC crystal films 12. The same thing can be observed in the case of a wafer basket, and when the susceptor or wafer basket is exposed to the atmosphere, moisture etc. enters into these holes 13 and gaps 14. In addition, cases have been observed in which contamination sources such as metals have entered the holes and crevices.

? [Problems to be Solved by the Invention] Therefore, during the high-temperature evitaxial elongation process, the jigs H20, O2, etc. come out from these holes 13 and gaps 14 and diffuse inside the reactor, causing the diffused O■ and contaminants are incorporated into the epitaxial layer, degrading the quality of the elongated epitaxial film. In addition, in the case of a wafer basket, it is used to hold silicon wafers, and when the wafers are placed in a high-temperature furnace for high-temperature processing such as annealing, oxide film formation, etc., the wafers are +120 from the basket
There is a problem that metals such as , O and metal adhere to the surface of the wafer.

Therefore, the present invention provides a jig for manufacturing semiconductor devices such as a susceptor to H. The object of the present invention is to provide a structure with fewer adsorption sites into which contaminants, etc., can enter.

[Means for solving the problem] The above problem can be solved by coating carbon graphite with a film that makes its surface non-porous, and then coating it with a polycrystalline silicon carbide (SiC) film by chemical vapor deposition. The problem is solved by the resulting non-porous semiconductor device manufacturing jig.

? Effect] The upper figure is a diagram of an embodiment for explaining the principle of the present invention.
In the figure, the same parts as those shown in FIG. 2 are denoted by the same reference numerals, and 15 is a glassy carbon film. Carbon graphite 11 is porous as described above, and Si
Since the C polycrystalline film 12 is in a polycrystalline state, it easily contains moisture, etc. However, the glassy carbon film 15 covers the surface of the carbon graphite 11 by filling in pores l3, thereby changing the porous surface state of the carbon graphite 11. This changes the material into a dense, non-porous state and prevents I1■0, 0■, etc. from entering.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

In the embodiment of the present invention, the surface of the susceptor 21 is coated with a film that makes the surface part non-porous, for example, a glassy carbon film 15, thereby forming the carbon graphite 11 that constitutes the susceptor 2l. The holes 13 are filled as shown in FIG.

To create the glassy carbon film 15, a resin such as a Cl-based composition or phenol is applied to the surface of the susceptor 21, and the resin is carbonized in an inert atmosphere at a high temperature of 1300°C to deactivate the composition. Change to C for quality.

Or, in place of the above, CH. The surface of the susceptor 2L is covered with a pore-free, highly anisotropic graphite pie-shaped graphite (pyrolytic graphite) film that is pore-free and has strong anisotropy. Good too.

An example is shown in which a susceptor coated with a galanocarbon film 15 is used in the Si epitaxial process.

Kaicho conditions: Temperature: 1100°C Gas: SiHzα2/H2 Pressure: 760 Torr When comparing the Si epitaxial film grown under these conditions with the S+ epitaxial film made using a conventional susceptor, the number of shallow pits was 10. In the example using the susceptor according to the present invention, the number of shallow bits is 103 bits/crt! Met.

To explain shallow bits here, after a Si epitaxial layer is formed on a wafer, when the surface of the elongated Si film is lightly etched and observed, fine sand-like pits (holes) are observed. It is called shallow bit. If the number of shallow pits is large, the quality of the Si epitaxial film is poor, so the number of shallow bits is
It serves as a standard for determining the film quality of epitaxial membranes. In the embodiment of the present invention, the number of shallow bits is reduced by three orders of magnitude compared to the conventional example. ? Effects of the Invention) As described above, according to the present invention, a glassy carbon film is formed on the surface of the carbon graphite constituting the susceptor, the pores of the carbon graphite are filled, and the surface is made of a dense material. This prevents HzO from entering the carbon graphite when the susceptor is exposed to the atmosphere, and thereby prevents the emission of 11■0,0■ from the susceptor in the epitaxial length. , HzO and the like are not introduced into the epitaxial layer, and the quality of the epitaxial layer can be improved, which greatly contributes to improved yield.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention. Figure 2 is a sectional view of a conventional example; FIG. 3 is a sectional view of a susceptor on which a wafer is placed. In the figure, 11 is carbon graphite, 12 is a SiC polycrystalline film; 13 is a hole; 14 is a gap, 15 is a glassy carbon film; 21 is the susceptor, 22 is a wafer shows. Figure 1

Claims (1)

[Claims] A non-porous material obtained by coating carbon graphite (11) with a film (15) that makes its surface non-porous, and then coating it with a silicon carbide (SiC) polycrystalline film (12) by chemical vapor deposition. Jig for manufacturing semiconductor devices.