JPS58141525A - Preparation of silicon carbide structural member for semiconductor - Google Patents

Abstract

PURPOSE:To economically manufacture a silicon carbide structural member for semiconductor including less impurity and having smooth surface by removing the quartz glass tube after the gas phase deposition of SiC on the internal wall or external wall of the quartz glass tube through reaction of gas compound including C and Si. CONSTITUTION:An external tube 1 is exhausted to a vacuum condition of 1mm.Hg or less, a carbon electrode 7 is heated up to 1,200-1,400 deg.C by supplying a power to a high frequency induction coil 5 in view of indirectly heating a quartz glass tube 10. When it reaches a certain temperature, trichloromethylsilane is introduced from the gas supply tube 11 with hydrogen used as the carrier gas. A raw material gas is thermally decomposed and deposited as SiC film 12 on the external wall of tube 10 by the gas phase deposition method. When the specified time has passed resulting in deposition of film in the thickness of 3mm. or more, supply of raw material gas is stopped. AFter the film is sufficiently cooled, the tube 10 on which the SiC film 12 is coated is taken out of the external tube 1 and it is dipped into the hydrofluoric acid, the tube 10 is removed by dissolving and thereby a silicon carbide furnace core tube for semiconductor consisting of the SiC film 12 can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a silicon carbide component for semiconductors.

In the manufacture of semiconductor devices, many structural members such as furnace core tubes used in the diffusion process, oxidation process, etc. are made of quartz glass. However, when semiconductor devices are manufactured using a quartz glass furnace tube, the quartz glass easily softens and deforms at high temperatures, and is easily devitrified, so the life of the furnace tube is short. Therefore, in recent years, silicon carbide furnace core tubes have come into use.

Conventionally, silicon carbide furnace core tubes are made of trichlorosilane.

CVD method (ch.
It is manufactured by a method in which silicon is deposited in a vapor phase on the surface of a carbon substrate using a chemical vapor deposition method) and SiC is generated, and then the carbon substrate is oxidized and removed.

However, the conventional method described above has the following drawbacks.

(1) Carbon substrates are generally manufactured with few impurities; it is difficult to blue them. Therefore, when a silicon carbide furnace core tube manufactured without any treatment on the carbon substrate is used for manufacturing a semiconductor device, the % performance of the semiconductor device is deteriorated. Therefore, it is necessary to perform a purification treatment on the carbon substrate by a method such as subjecting it to high temperature heat treatment in a halogen gas atmosphere, which requires a huge amount of expense and is not economical. This is particularly noticeable when manufacturing large-sized products.

(2) Since carbon substrates are generally porous, the silicon deposited in a vapor phase on the optical surface also enters the pores of the carbon substrate, forming a so-called "legged" structure7.For this reason, when the carbon substrate is baked, In silicon carbide furnace core tubes manufactured by punching (oxidation removal), the ``footed'' structure becomes protrusions and loses smoothness. Even if a furnace core tube with an unsmooth inner surface has high chemical purity, it is difficult to insert or remove the wafer from the furnace core tube during the heat treatment process for semiconductor wafers.
This gives vibration to the evaporator, which causes crystal defects (
(slip dislocation). As a result, the % performance of the manufactured semiconductor device deteriorates.

(3) The unevenness on the surface of the cardin substrate is unique to the CVD method (
This promotes the generation of pull and roughens the surface of the vapor deposited film.
This makes handling such as acid treatment before use of the product difficult.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and it is an object of the present invention to provide a method for manufacturing a silicon carbide constituent member for semiconductors that has few impurities and has a smooth surface.

. Hereinafter, an embodiment in which the present invention is applied to the manufacture of a silicon carbide furnace core tube will be described with reference to the drawings. The figure shows a CVD apparatus g used for manufacturing the silicon carbide furnace core tube for semiconductors of the present invention, and in the figure 1 is a quartz glass outer cylinder tube. A jacket 2 and a lower lid 3 are disposed on the upper and lower end surfaces of the outer cylindrical tube 1, respectively. An exhaust pipe 4 is inserted into the medium heat opening of the upper cover 2. A high frequency induction coil 5 is disposed on the outer periphery of the outer cylindrical tube 1. Further, an annular insulating support member 6 is installed on the lower cover 3 inside the outer tube 1, and has an inner diameter of 200 wm on the support member 6.

A cylindrical carbon electrode 7 with a length of 2000 mm is provided. Is there a heat insulating car between this car and the outer tube 1? Filled with felt 8. Historically, a support stand 9 is installed on the lower cover 3 inside the carbon electrode 7, and on the support stand 9 there is a diameter of 100 tram.
r length 1800 tm.

A quartz glass tube 10 with a wall thickness of 1.0 mm is arranged. A gas introduction tube 1) is inserted from the outside between the quartz glass tube 10 and the carbon electrode 7 by penetrating the lower cover 3.

Next, a method of manufacturing a silicon carbide furnace core tube for a semiconductor using the above-mentioned C'VD apparatus will be explained.1. First, the exhaust pipe 4 was evacuated to make the inside of the outer cylinder I#1 a vacuum of 1+nmHg or less. Next, the carbon electrode 7 was heated by energizing the high-frequency induction coil 5, and the temperature was raised to 1200 to 1400°C, thereby indirectly heating the quartz glass tube lθ. Subsequently, after reaching a certain temperature, trichloromethylsilane was introduced from the gas introduction pipe 11 using hydrogen as a carrier gas.

When the raw material gas reached the heated part, it was thermally decomposed and began to be deposited in the vapor phase as the SIC film 12 on the outer wall of the quartz glass tube 10. The reaction time was set so that the film thickness of this SIC film 12 was 3 curvature or more, and after a predetermined period of time, the introduction of the raw material gas was stopped to stop the reaction. .

Subsequently, the high frequency induction coil 5 was de-energized and allowed to cool naturally. After sufficiently cooling, the S1C film 12 is removed from the outer tube 1.
The quartz glass tube 10 coated with was taken out.

Subsequently, the tube was immersed in hydrofluoric acid to dissolve and remove the quartz glass tube 10 to obtain a semiconductor silicon carbide furnace core tube made of the SiC film 12. Here, when the quartz glass tube 10 coated with the SiC film 12 was taken out from the outer tube 1, cracks had occurred in the quartz glass tube 1° due to the difference in thermal expansion between the two. These conditions are advantageous when the quartz glass tube 1o is dissolved and removed using hydrogen acid. Also, sl
Although there were almost no cracks in the C film 1o, cracks did occur in some cases. However, the occurrence of cracks and cracks in the S50 film 10 can be solved by changing the diameter and wall thickness of the quartz glass tube 10 and the thickness of the SiC film J2. l According to the above embodiment, since the quartz glass tube 1o with an extremely smooth surface is used as the substrate on which the SfC film 12 is deposited in a vapor phase, the inner wall of the silicon carbide furnace core tube to be manufactured is smooth. be. Furthermore, the quartz glass tube 10 does not contain any impurities that would deteriorate the quality of the silicon carbide furnace core tube, and
Since it is completely removed by hydrofluoric acid, the silicon carbide furnace tube produced has fewer impurities.

In addition, from the following example, Suritsuno dislocation occurs6- It was confirmed that it would not.

Experimental example Outer diameter 110mm, inner diameter 100mm manufactured by the method of the present invention
A silicon carbide furnace core tube with a length of 1,500 mm was installed in the oxidizer, and both ends of the furnace core tube were made airtight with quartz glass caps (chi-day rubbing). Silicon Ueno® was introduced into this furnace core tube, and the operation of inserting and removing the Pheno® was repeated 10 times at a rate of 10 w/min in a dry 02 atmosphere at 1200°C. After this operation, Ueno was inspected, but no slip dislocation was observed as in the case of using a quartz glass furnace core tube.

From the above experimental examples, it was found that the smoothness of the inner surface of the silicon carbide furnace tube manufactured by the method of the present invention is equivalent to that of a quartz glass wire furnace tube. .

Incidentally, in the above embodiment, the outer wall of the quartz glass tube 10 is coated with SiC.
Although the film 12 was deposited in a vapor phase, a SiC film may be deposited in a vapor phase on the inner wall of the quartz lath W10. In addition, while moving the high-frequency work coil, Si
If the C film is deposited in a vapor phase, a long silicon carbide furnace core tube with a large diameter can be obtained. By this method, for example, an outer diameter of 150 w, an inner diameter of 140 m, a length of 2000 +
A +a silicon carbide furnace core tube could be obtained.

In addition, by a method similar to the method described above, the gaseous compounds serving as the carbon source and the nitrogen source are reacted to deposit S k,% on the inner or outer wall of the quartz glass tube in a vapor phase, and then the quartz glass tube is removed. For example, a silicon nitride structural member for semiconductors can be manufactured.As described above, according to the present invention, it is possible to provide a method for manufacturing a silicon carbide structural member for semiconductors that has few impurities and has a smooth surface. be.

[Brief explanation of drawings]

The figure is a sectional view showing a CVD apparatus used in an example of the present invention. 1... Quartz glass outer tube, 2... Top lid, 3...
Lower lid, 4... Exhaust pipe, 5... High frequency induction coil, 6
...Insulating support material, 7...car? electrode, 8...
Carn felt, 9... Support stand, 10... Quartz glass tube, 1... Gas introduction tube, 12... SiCM. 1 ] 111 Go 1 113- Kan 2 Ku 3

Claims (1)

[Claims] A method for producing a silicon carbide component for semiconductors, which comprises reacting a gaseous compound containing C and Si to deposit SiC in a vapor phase on the inner or outer wall of a quartz glass tube, and then removing the quartz glass tube. .