JPH0710648A - Thermally insulating material for semicondcutor heat treatment oven - Google Patents

Abstract

PURPOSE:To provide a thermally insulating material for a semiconductor heat treatment oven, of high thermal insulation, having no adverse effects on high- purity semiconductor wafers. CONSTITUTION:The thermally insulating material the surface of which consists of a gas-impermeable dense silicon carbide matter is 1-20% in porosity and contains a sintered compact of silicon carbide grains.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating furnace for a semiconductor heat treatment furnace which is particularly used for a semiconductor heat treatment work for heating a semiconductor wafer to form a silicon oxide film on the surface thereof and diffusing impurity atoms therein. Regarding materials

[0002]

2. Description of the Related Art Conventionally, in the work of heat-treating a semiconductor wafer in a furnace core tube of a semiconductor heat treatment furnace, the semiconductor wafer is heated by a heater while being placed on a wafer support boat made of quartz glass or silicon carbide. .

In this heat treatment, the end of the furnace core tube is generally covered.

However, the thermal insulation of the furnace core tube is not sufficient with only such a lid. Particularly, in a horizontal type semiconductor wafer heat treatment furnace, the heat insulating property in the length direction (axial direction) of the furnace core tube is remarkably insufficient, and the thermal efficiency is poor.
Therefore, there is a disadvantage that the temperature of the soaking part in the furnace core tube rises easily due to the heating of the heater.

For the purpose of eliminating this drawback, a plate-shaped heat insulating material made of quartz glass or silicon carbide is placed near the end of the wafer support boat.

Explaining this heat insulating material made of silicon carbide, there is used a dense silicon carbide / silicon composite material in which silicon is impregnated in a silicon carbide sintered body, or a surface of which is coated with silicon carbide.

[0007]

However, since the above-mentioned heat insulating materials of quartz glass and silicon carbide have high thermal conductivity and have a small effect of blocking radiant heat, the heat insulating properties of these heat insulating materials are satisfactory. However, the above-mentioned drawbacks cannot be fully eliminated.

Various other materials can be considered as a heat insulating material having a sufficient heat insulating property. However, a heat insulating material for a semiconductor heat treatment furnace is required to have not only sufficient heat insulating properties but also not to adversely affect a high-purity semiconductor wafer and to be inexpensive. Quartz glass and other materials such as silicon carbide do not fully meet such requirements.

It is an object of the present invention to provide a heat insulating material for a semiconductor heat treatment furnace which has a high heat insulating property and does not adversely affect a high purity semiconductor wafer.

[0010]

According to the present invention, the surface is made of dense gas-impermeable silicon carbide and has a porosity of 1% to 2%.
The gist is a heat insulating material for a semiconductor heat treatment furnace, which is 0% and contains a sintered body of silicon carbide particles.

[0011]

EXAMPLE A heat insulating material for a semiconductor heat treatment furnace according to a preferred embodiment of the present invention will be described.

The surface of this heat insulating material for a semiconductor heat treatment furnace is made of gas-impermeable dense silicon carbide, and the porosity of this heat insulating material is 1% to 20%. It contains a sintered body of particles.

A method for manufacturing such a heat insulating material for a semiconductor heat treatment furnace will be described. An organic binder is added to silicon carbide particles, they are kneaded and molded, the molded product is fired, and the fired body is heated at a high temperature. A high-purification treatment is performed and a gas-impermeable dense silicon carbide is coated on the surface of the fired body to obtain a heat insulating material.

As described below, a heat insulating material for a semiconductor heat treatment furnace was manufactured by this manufacturing method.

First, silicon carbide powder having an average particle size of 44 μm and phenol resin are kneaded, dried, granulated, and then powdered phenol resin is added to form a powder containing 20 to 50 wt% of the total amount of phenol resin. Then, the molded product was fired in a non-oxidizing atmosphere to obtain a fired body. afterwards,
Purification treatment was performed on the fired body in a furnace while flowing a hydrochloric acid (HCl) gas at a temperature of 1500 ° C. The porosity of the fired body after the purification treatment was 12%.

Thereafter, 2 g to 20 g per minute of trichloromethylsilane using hydrogen gas as a carrier gas is supplied to the surface of the fired body in the reaction furnace so that the fired body is made of gas impermeable dense silicon carbide. It was coated with a film having a thickness of 0.1 mm.

In this way, a heat insulating material for a semiconductor heat treatment furnace was obtained. This heat insulating material has a disk shape and an outer diameter of 1
It was 80 mm and its thickness was 2 mm. This heat insulating material contained a sintered body of silicon carbide particles, and the porosity of the heat insulating material was 11%.

Next, two pieces of such heat insulating material 1 were produced and, as shown in FIG. 1, placed one on each end of a wafer support boat 2 made of quartz glass. They have an inner diameter of 20
It was placed in a 0 mm cylindrical quartz glass furnace core tube 3, and the heat insulating material 1 was set so as to be positioned at both ends of the soaking part A of the furnace core tube 3. The temperature of the soaking part A of the furnace core tube 3 is raised to 10 by heating with the heater 4 arranged outside the furnace core tube 3.
It was kept at 00 ° C.

The temperature distribution inside the furnace core tube 3 at this time is shown by a solid line 10 in the graph of FIG. The horizontal axis of this graph corresponds to the position of the furnace core tube 3 in the axial direction.

Comparative Example Two pieces of the above-mentioned conventional heat insulating material made of quartz glass and two pieces of heat insulating material made of silicon carbide were prepared. The shape of these heat insulating materials was the same as the shape of the heat insulating materials of the above-described examples (that is, a disk shape having an outer diameter of 180 mm and a thickness of 2 mm).

In the same manner as in the above-mentioned embodiment, those heat insulating materials were arranged at both ends of the soaking section of the furnace core tube.

The temperature distribution inside the furnace core tube when the heat insulating material of quartz glass is arranged is shown by a broken line 12 in the graph of FIG. 2, and the temperature distribution inside the furnace core tube when the heat insulating material made of silicon carbide is arranged. The temperature distribution is shown by a chain double-dashed line 11.

Further, the temperature distribution inside the furnace core tube when the heat insulating material is not arranged is shown by a one-dot chain line 13.

As is clear from FIG. 2, the heat insulating material of the example is superior to the heat insulating material of the comparative example in the heat insulating property in the axial direction of the furnace core tube, and the heat insulating material of the inside and outside of the soaking section is excellent. The space is well insulated.

The present invention is not limited to the above embodiment. For example, the shape of the heat insulating material is not limited to the disk shape.

Further, the fired body is not limited to the above-mentioned one, and a conventional fired body of silicon carbide can be adopted. For example, a fired body produced by using another conventional binder instead of the phenol resin can also be used.

The gas-impermeable dense silicon carbide material can be formed by any other conventional method than the above-mentioned method.

[0028]

As described in detail above, according to the heat insulating material for a semiconductor heat treatment furnace of the present invention, silicon carbide particles as an aggregate are provided inside a heat insulating material having a gas-impermeable dense silicon carbide surface. It has high heat insulating properties, high mechanical strength, and strong thermal shock, since it contains spores and has pores.

Further, since the heat insulating material has a porosity of 1% to 20%, the heat insulating property can be significantly improved as compared with the conventional heat insulating material made of quartz glass or silicon carbide.

Since the surface of the heat insulating material is made of gas impermeable dense silicon carbide and has a high purity, it does not adversely affect the high purity semiconductor wafer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state where a heat insulating material for a semiconductor heat treatment furnace according to a preferred embodiment of the present invention is arranged in a furnace core tube.

FIG. 2 is a graph showing a temperature distribution in the axial direction of the furnace core tube shown in FIG.

[Explanation of symbols]

 1 Heat Insulation Material for Semiconductor Heat Treatment Furnaces 2 Wafer Support Boat 3 Furnace Core Tube 4 Heater A Soaking Part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuharu Sasa 378 Oguni-machi, Oguni-cho, Nishiokitama-gun, Yamagata Prefecture Inside the Oguni Factory of Toshiba Ceramics Co., Ltd. (72) Katsunori Sato 378 Oguni-cho, Oguni-machi, Nishiokitama-gun, Yamagata Prefecture Address Toshiba Ceramics Co., Ltd. Oguni Factory (72) Inventor Yasumi Sasaki Oguni Town, Oguni Town, Nishikitama District, Yamagata 378 Oguni Town, Toshiba Ceramics Co., Ltd. Oguni Factory

Claims (1)

[Claims] 1. A semiconductor heat treatment furnace having a surface made of a gas-impermeable dense silicon carbide material, having a porosity of 1% to 20% and containing a sintered body of silicon carbide particles. Insulation.