JP2828457B2 - Heat treatment furnace for semiconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to diffusion, oxidation, and the like of semiconductors such as silicon wafers.
The present invention relates to an improvement in an inlet tube for introducing a heat treatment gas into a furnace core tube of a gas in a heat treatment furnace for semiconductor used in a heat treatment step such as annealing.

[Prior Art] Various gases such as oxygen, nitrogen, hydrogen, and water vapor are used in heat treatment steps such as diffusion, oxidation, and annealing in the semiconductor industry. For example, in the oxidation step, nitrogen and oxygen are often used simultaneously.

Conventionally, in this oxidation step, the treatment is performed while simultaneously flowing a plurality of heat treatment gases from a gas introduction pipe provided in a process tube, and in many cases, the mixing of these heat treatment gases is left to the natural.

However, since some types of heat treatment gases are difficult to mix, the method of leaving the mixing of multiple gases naturally causes a problem in that the thickness of the oxide film of the silicon wafer subjected to the oxidation treatment varies. there were. (Of course, the variation in the thickness of the oxide film has other causes.
For example, the temperature of the silicon wafer is not uniform, the flatness of the surface, the flow rate of the gas, and the like. [Problems to be Solved by the Invention] Therefore, conventionally, a container for mixing a plurality of heat treatment gases is provided in the middle of the gas introduction pipe, and the heat treatment gas is mixed in the container before the process. The method of introducing into a tube was taken. However, since the gas introduction pipe and its jig are often made of stainless steel, in this method, the gas introduction pipe and its jig are often oxidized by the gas for heat treatment and rust or the like is generated on the surface thereof. . The rust or the like contaminates the heat treatment gas, resulting in a problem that the silicon wafer to be oxidized is contaminated.

It has been known that the heat treatment gas is preferably mixed at a temperature as high as possible. This is because the higher the temperature, the lower the viscosity of the gas itself and the easier it is to mix. However, in the case of a stainless steel gas introduction pipe or jig, if the temperature is raised, the problem of corrosion due to oxidation occurs as described above, and therefore it is impossible to raise the temperature itself.

[Means for Solving the Problems] The present inventors have made various studies in view of the above-mentioned actual situation, and as a result, have reached the present invention.

That is, the present invention includes a furnace core tube, a gas introduction tube connected to an open end of the furnace core tube, and a gas mixer disposed inside the gas introduction tube, wherein the gas mixer comprises: SiC
A core rod made of a high-quality material, and formed outside the core rod;
A spiral-shaped blade made of a SiC material, and the spiral-shaped blade is separated from the inner wall of the gas introduction pipe, and is provided with a plurality of semiconductor heat treatments supplied to the gas introduction pipe. The semiconductor heat treatment furnace is characterized in that the gas is mixed by the gas mixer and then sent to the furnace core tube.

In the present invention, the SiC material is, for example, a SiC sintered body or a SiC material impregnated with Si. The heat resistance of the SiC sintered body or the SiC material impregnated with Si is higher than quartz glass by 200 ° C. or more, and the chemical purity thereof is equivalent to that of quartz glass.

The SiC sintered body has pores, and gas can flow through the pores. The SiC material impregnated with Si is obtained by impregnating the pores of a SiC sintered body with Si. Since the pores of the SiC sintered body are buried by the impregnation of Si, gas flow is impossible. In the present invention, both can be used effectively.

In addition, the SiC material used in the present invention has a higher oxidation resistance at high temperatures with respect to a normal oxidizing gas containing oxygen and the like than a metal such as stainless steel, and has the above-described problems such as corrosion. Does not occur. Further, since the shape of the SiC material can be freely given by bonding, a complicated spiral shape can be manufactured.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing a furnace core tube and a gas introduction tube of a heat treatment furnace for semiconductor of the present invention, partially cut away.

In FIG. 1, reference numeral 1 denotes a furnace core tube for semiconductor heat treatment, in which a semiconductor to be subjected to heat treatment such as a silicon wafer is placed. Examples of the heat treatment include a diffusion treatment and an oxidation treatment.

The gas introduction pipe 2 is connected to the open end of the furnace core tube 1, that is, the connection portion 3 by spherical contact or planar contact. A gas mixer 4 is provided inside the gas introduction pipe 2.

The gas mixer 4 has a spiral-shaped blade plate 6 around a core rod 5. This gas mixer 4 (core rod 5
And the spiral blade 6) are made of a sintered SiC or S
Manufactured using i-impregnated SiC material. These SiC
Since the quality material has a characteristic that it has good adhesiveness and can freely give a shape, a material having a complicated shape such as a spiral shape can be easily manufactured. Further, the heat resistance is higher than quartz glass by 200 ° C. or more, has oxidation resistance to withstand radiant heat of 1200 ° C., and is excellent in corrosion resistance. For this reason, there is no risk of contaminating a semiconductor to be subjected to a heat treatment such as a silicon wafer.

When various gas bodies A are introduced into the gas introduction pipe 2,
These gas bodies A collide with the spiral blade plate 6 and are disturbed, and then collide with the inner wall of the gas introduction pipe 2. Thereafter, this step is repeated. In this way, the gas body A is repeatedly mixed by the gas mixer 4 while passing through the introduction pipe 2, and is sent to the inside of the furnace core tube 1 after being uniformly mixed.

Here, one end (the right end in FIG. 1) of the gas mixer 4 is fixed, but it may be rotated.

[Effects of the Invention] As described above, according to the heat treatment furnace for a semiconductor of the present invention, the heat treatment gas can be favorably mixed with a simple structure, and there is no possibility of contaminating the semiconductor to be subjected to the heat treatment. This has the effect.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a furnace core tube and a gas introduction tube of a heat treatment furnace for semiconductor of the present invention, partially cut away. DESCRIPTION OF SYMBOLS 1 ... Furnace core pipe, 2 ... Gas introduction pipe 3 ... Spherical or flat connection part 4 ... Gas mixer, 5 ... Core rod 6 ... Spiral blade plate

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazunori Meguro 378, Oguni-machi, Oguni-machi, Oguni-machi, Nishiokitama-gun, Yamagata Pref. JP-A-2-254169 (JP, A) JP-A-63-54718 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/22 H01L 21/205 H01L 21/31

Claims (1)

(57) [Claims] 1. A furnace core tube, a gas introduction tube connected to an open end of the furnace core tube, and a gas mixer disposed inside the gas introduction tube, wherein the gas mixer is SiC And a spiral-shaped blade formed outside the core and formed of a SiC material, and the spiral-shaped blade is separated from the inner wall of the gas introduction pipe. A plurality of semiconductor heat treatment gases supplied to the gas inlet tube are mixed by the gas mixer and then sent to the furnace core tube.