JP3276429B2 - Semiconductor wafer processing members - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer processing member such as a process tube or a wafer boat.

[0002]

2. Description of the Related Art In the past, high-purity quartz glass was exclusively used as a material for semiconductor wafer processing members, but recently Si-SiC-based materials have been widely used together with quartz glass. The Si-SiC-based material has sufficient thermal shock resistance even in a high-temperature heating / cooling cycle for diffusing impurities in a semiconductor wafer, and has a high mechanical strength and is an excellent material.

[0003]

However, the conventional Si
-SiC-based semiconductor wafer processing members have not always been sufficiently satisfactory in strength and purity.

In particular, when the semiconductor processing member has a complicated shape such as a boat, the wafer is placed and the temperature is increased.
During the repetition of the heat cycle of lowering the temperature, a portion weak in strength was sometimes broken by thermal stress.

[0005] Further, a Si-SiC-based semiconductor wafer processing member is prepared by subjecting a silicon carbide powder as a raw material to acid cleaning, molding, purification,
It is generally manufactured through various steps such as impregnation of high-purity Si and final acid treatment. However, even if the cleaning treatment is performed through such a complicated process, a trace amount of impurities still remains in the molded body, which has had a great effect on the performance deterioration of the semiconductor wafer. In particular, impurities trapped inside the silicon carbide particles as the raw material are extremely difficult to remove even in the subsequent cleaning treatment. Such impurities are diffused and released from inside by heating at a high temperature when the semiconductor wafer processing member is used. This is believed to contaminate the semiconductor wafer.

[0006]

SUMMARY OF THE INVENTION The present invention provides a Si-SiC
In the system-based semiconductor wafer processing member, the structure has at least two layers including a surface layer portion and a remaining portion, and the surface layer portion has an average grain size.
It is composed of a matrix of fine powder SiC and Si having a diameter of 5 to 18 μm , and the remainder is coarse powder S having an average particle diameter of 50 to 100 μm.
iC and a matrix of SiC and Si in the form of fine powder having an average particle size of 10 to 20 μm , and the surface layer portion is at least 300 μm.
The gist of the present invention is a semiconductor wafer processing member having a thickness of μm and a total metal impurity content of a surface layer portion of 1 ppm or less.

[0007]

Since the surface layer of the Si-SiC-based semiconductor wafer processing member does not contain coarse SiC but is composed of fine SiC powder and a matrix of Si, the semiconductor wafer processing member is heated and cooled in a heat cycle. Even if thermal stress is generated due to the temperature difference by repeatedly performing the above, breakage is difficult.

In addition, S in the surface layer of the semiconductor wafer processing member
Since the iC particles are small, impurities can be removed to the inside of the SiC particles by performing high-purity treatment at a high temperature using halogen or hydrogen halide at the stage of the silicon carbide molded body. Therefore, even if the semiconductor wafer is heated to a high temperature, impurities are not diffused and emitted from the inside, and the semiconductor wafer is hardly contaminated.

The reason for limiting the thickness of the surface layer composed of the fine powdered SiC and Si matrix to 300 μm or more is that if the surface layer is less than 300 μm, breakage is likely due to thermal stress due to temperature difference. .

Preferably, the thickness of the surface layer is 500 to 150.
0 μm. The average particle size of the SiC fine powder in the surface layer is 5-1.
It is preferably 8 μm. The average particle size of the remaining coarse particles is 5
0 to 100 μm, the average particle size of the fine powder is 10 to 20 μm
It is preferred that

Further, at least the purity of the surface layer, when analyzed by a flameless atomic absorption spectrometry, has an average Fe of 0.5 ppm or less, and the Fe, Ni, Cu, Na, C
a, V, K, Cr, Mg, and Mr.
It is preferably 0 ppm or less, and it is preferable that Al exceeds 1.0 ppm.

[0012]

EXAMPLE A phenolic resin was added as a binder to coarse powder having an average particle diameter of 60 μm and fine powder having an average particle diameter of 10 μm, and kneaded with a kneader. This is designated as raw material 1.

Next, phenol resin is added as a binder to the fine powder having an average particle size of 10 μm, and the mixture is kneaded in a kneader. This is designated as raw material 2.

A raw material 1 and a raw material 2 are mixed with a plunger molding machine 3
(FIG. 1). At this time, raw material 2
Is placed circumferentially on the inner wall of the cylinder 4 and the raw material 1 is replaced with the raw material 2
To the center of Thereafter, the piston 5 is moved in the direction of the arrow, and is extruded from a predetermined die 6 and molded. After baking it, a high purity treatment is performed at 1600 ° C. or higher with HCl gas using an inert gas as a carrier gas, then impregnated with Si, and a rod 7 (diameter 10 mm,
(Length 100 mm). The surface layer 8 of the rod 7 had a thickness of 1000 μm. If the surface layer is polished in the final step, this thickness is reduced accordingly. Si was entirely impregnated, and the surface layer portion 8 and the remaining portion 9 had an integral double structure.

As a comparative example, a phenolic resin was added as a binder to a coarse powder having an average particle diameter of 60 μm and a fine powder having a average particle diameter of 10 μm, kneaded with a kneader, extruded in the same manner with a plunger molding machine, and subjected to a high-purification treatment after firing. Further S
rod impregnated with i (diameter 10mm, length 100mm)
Was made.

These rods were heated to a predetermined temperature, dropped into water when the temperature was sufficiently uniform, and the operation was repeated until the rods were broken. Table 1 shows the results.

[0017]

[Table 1] Further, the bending strength was measured according to JIS standard R1601. Table 2 shows the results.

[0018]

[Table 2] In addition, the chemical analysis value of the total amount of metal impurities in the surface layer portion of the rod used in the above-described example was 1 ppm or less. Analysis was performed using a solution extracted with an acid after heating in a Teflon pressure vessel. For details of the analysis method, see the summary of lectures on “Analytical Chemistry Seminar for Fine Ceramics” sponsored by the Nagoya Industrial Technology Association (197-205, November 15 and 16, 1984).
Page.

3 and 4 show the structure of the impregnated body. FIG.
5 is a photograph showing a partial cross section of a semiconductor wafer processing member according to the present invention. FIG. 4 is a photograph showing a conventional type for comparison. Incidentally, the surface of the sample shown in FIG.

[0020]

As described above, the Si-SiC-based semiconductor wafer processing member of the present invention has a surface portion composed of a fine powder SiC and a Si matrix having a thickness of at least 300 μm or more. The performance is improved.

Further, S of the surface layer of the semiconductor wafer processing member is
Since the iC particles are fine powder, at the stage of the silicon carbide molded body,
By performing high-purity treatment at a high temperature using halogen, hydrogen halide, or the like, impurities inside the SiC particles can be easily removed, and a high-purity semiconductor wafer processing member can be obtained.

Further, when a high-purity SiC film is formed on the obtained semiconductor wafer processing member by the CVD method, the surface can be further purified. In this case, it has a three-layer structure.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a plunger molding machine for manufacturing a semiconductor wafer processing member of the present invention.

FIG. 2 is a cross-sectional view of the semiconductor wafer processing member of the present invention.

FIG. 3 is a micrograph showing the cross-sectional particle structure of the semiconductor wafer processing member of the present invention.

FIG. 4 is a micrograph showing a cross-sectional particle structure of a conventional semiconductor wafer processing member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material 2 Raw material 3 Plunger molding machine 4 Cylinder 5 Piston 6 Cap 7 Rod 8 Surface part 9 Remaining part ◆

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuji Matsuda 378 Oguni-machi, Oguni-machi, Oguni-machi, Nishiokitama-gun, Yamagata Prefecture Inside the Oguni Plant, Toshiba Ceramics Co., Ltd. 378 Toshiba Ceramics Co., Ltd. Oguni Works (56) References JP-A-62-12666 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/22 H01L 21 / 205 C01B 33/02

Claims (1)

(57) [Claims] An Si-SiC-based semiconductor wafer processing member having a structure of at least two layers including a surface layer portion and a remaining portion, wherein the surface layer portion is a fine powder S having an average particle size of 5 to 18 μm.
It is composed of a matrix of iC and Si, and the rest is average particle size
SiC of coarse powder of 50 to 100 μm and average particle size of 10 to 20
A semiconductor wafer processing member comprising a matrix of SiC and Si in fine powder of μm, a surface layer having a thickness of at least 300 μm, and a total metal impurity content of the surface layer of 1 ppm or less.