JPS61274318A - Apparatus for heat-treating semiconductor product - Google Patents

Abstract

PURPOSE:To enable uniform heat treatment by providing the furnace core tube with a construction of double tubes, one of which is an inner tube that is partially composed of a sintered substance of porous SiC, and providing outside the inner tube an outer tube for flowing a gas into which the gas can flow and can be discharged therefrom, thereby preventing the occurrence of the concentration difference of the gas to be supplied to semiconductor products. CONSTITUTION:A gas is kept flowing in an outer tube 24, and a cap 30 is opened, allowing the semiconductor wafers 22 carried on a diffusion board 21 to be delivered into an inner tube 25. At this time, the setting is performed so that the semiconductor wafers 22 are positioned at the position of a venting part 25a of the inner tube 25 which is composed of a sintered substance of porous SiC. The set inner tube 25 is delivered in through the cap 31 within the outer tube 24 and received in the outer tube 24. The gap which has flowed in through a gas inlet port 27 passes between the outer tube 24 and the inner tube 25, and the gas is made to flow into the inner tube 25 only through the venting part 25a composed of a sintered substance of porous SiC. The gas is uniformly poured in parallel with the semiconductor wafers 22 and from the circumferential direction as shown by arrows, creeping around slowly, and thereafter it is discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat treatment apparatus for semiconductor articles, and more particularly to a diffusion apparatus for semiconductor wafers.

(Prior Art) Diffusion and oxidation techniques in the manufacturing process of semiconductor devices play a fundamental and important role in planar processes, which are the basis of today's LSI and VLS.

Here, a conventional heat treatment apparatus for semiconductor articles and its treatment method will be explained based on the drawings.

FIG. 5 is a sectional view of a conventional heat treatment apparatus for semiconductor articles.

In addition, here, the semiconductor wafer poc7! A diffusion device using , will be explained.

In the figure, 1 is a diffusion board, 2 is a semiconductor wafer, 3 is a heater, 4 is a reaction tube, 5 is a cap of the reaction tube, 6 is N8 and 0. a first inlet port through which gas flows; 7 is a gas inlet pipe; 8
is a second inlet into which gas containing P OC'l 2 flows; 9 is pulp; and 10 is an exhaust port.

As shown in this figure, first, the heater 3
The camp 5 at the exhaust side end is opened in the reaction tube 4 kept at a high temperature of about 6C, and the semiconductor wafer 2 mounted on the diffusion board 1 is inserted. At this time, N2 and 0□ are flowed into the reaction tube 4 from the end opposite to the exhaust side through the gas inflow pipe 7 from the first gas inlet 6. Further, the semiconductor wafer 2 is carried into the reaction tube 4 while being mounted on the diffusion board 1. After this, by opening the pulp 9, P
Gas containing OC1z (using a bubbler) is flowed into the reaction tube 4 from the second gas inlet 8 through the gas inlet pipe 7. Then, in the reaction tube 4, PtOs is generated by the reaction between POCI and 02. Diffusion is performed on the semiconductor wafer 2 using this as a diffusion source. After completing a predetermined diffusion, the cap 5 at the discharge side end is opened and the semiconductor wafer 2 is taken out. However, in this method, P! in the vicinity of the semiconductor wafer 2a near the gas inlet pipe 7 and in the vicinity of the wafer 2b on the exhaust side. 0. Since the gas flows are different and the semiconductor wafer 2 cannot be uniformly exposed to the PtOs gas, it has been difficult to perform a uniform diffusion process.

In order to solve this problem, a semiconductor wafer diffusion device as shown in FIG. 6 has also been attempted.

In the figure, 11 is a reaction tube, 12 is a gas introduction tube, and 13a to 1
3e is a gas introduction port formed in the gas introduction pipe 12-, and the other parts are the same as those shown in FIG. 5, and the explanation thereof will be omitted.

Next, to explain the method for diffusing semiconductor wafers using this diffusion device, the gas introduction tube 12 is extended to the inside of the reaction tube 11, and a mixed gas of Nt, O2, and POCl s is introduced into the reaction tube through the introduction ports 132 to 136. Let it flow into the tube.

According to this method, the gas concentration in the vicinity of semiconductor wafers 2a and 2b is improved more than with the diffusion device shown in FIG.

(Problems to be Solved by the Invention) However, even with the semiconductor wafer diffusion apparatus shown in FIG. The gas flow is different in the wafer 2d, and there is a problem in that it is difficult to perform a uniform diffusion process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat treatment apparatus for semiconductor articles that can eliminate the above-mentioned problems, prevent the occurrence of concentration differences in gases supplied to semiconductor articles, and perform uniform heat treatment.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a heat treatment apparatus for semiconductor articles in which the furnace core tube has a double tube structure, one of which is partially made of porous SiC sintered material. The inner tube is made of a solid body, and an outer tube is provided outside the inner tube through which gas can flow in and out.

(Function) According to the present invention, the gas flowing into the outer pipe 24 is transferred to the inner pipe 24.
It flows into the inner tube 25 from the ventilation part 25a made of porous SiC sintered body No. 5, is uniformly poured from the circumferential direction parallel to the semiconductor wafer 22, and has sufficiently circulated around the semiconductor wafer 22.
It is discharged from the ventilation section 25a. In other words, the inner tube 25
Since the gas concentration is equalized inside and the gas is slowly replaced, the processing surface of the semiconductor wafer is exposed to a uniform gas and heat-treated regardless of the position of the semiconductor wafer 22.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a sectional view of a heat treatment apparatus for semiconductor articles according to the present invention, FIG. 2 is a sectional view taken along line n-n' in FIG. 1, and FIG. 3 is a sectional view taken along line m-m' in FIG. .

In these figures, 21 is a diffusion board, 22 is a semiconductor wafer, 23 is a heater, 24 is an external tube made of a material such as quartz SiC, 25 is an internal tube, and 25a constitutes a part of the internal tube 25. , a tubular ventilation section made of a porous 1jsic sintered body located around the semiconductor wafer 22, 25b is a sealed section other than the ventilation section 25a, 26 is a leg provided on the inner tube 25, and the outer tube 24 It is placed so that it is in contact with the 27 is a gas inlet to the external pipe 24;
8 is a gas pipe, 29 is a gas system, 30 is an internal pipe 25
31 is the cap of the external pipe, 32 is the leg of the camp 30, and 33 is the exhaust port.

Next, the structure and material of the inner tube will be explained.

As shown in FIGS. 1 and 3, a semiconductor wafer 22
A ventilation section 25a made of a porous SiC sintered body of the inner tube 25 is arranged around the area where the inner tube 25 is located.

As this porous SiC sintered body, for example, "r Ibiceram" (trade name, manufactured by Ibiden Corporation) can be used.

Next, this porous SiC sintered body will be explained in detail. FIG. 4 is an enlarged structural diagram of this porous SiC sintered body. In the figure, 33 is a SiC bar, the length of which is about 10
0 μm 134 is the pore part, and the pore diameter is about 100 to 20
It is 0 μm.

This type of sintered body is manufactured using high-purity β-type SiC as a base material, and has a three-dimensional mesh structure in which plate-shaped crystals are intricately intertwined, taking advantage of the sintering properties of β-type fine powder. A major feature is that the pores are uniformly distributed throughout.

In addition, compared to conventional ceramic porous bodies (α type), (
1) It has excellent strength and heat resistance (can be used up to 16003C), (2) It is chemically stable and free from contamination, (3) It can be manufactured with a wide range of pore diameters, porosity, and specific surface areas, and (
4) It also has the advantage that products of various arbitrary shapes can be manufactured.

Such a porous StC sintered body is used in the ventilation section 2 of the inner tube.
5a, and the sealed portion 25b is constructed by, for example, filling the pores 34 of this sintered body with metal Si. As shown in FIGS. 1 and 2, the sealing portion 25b is disposed inside the outer tube 24 via legs 26. It should be noted here that unless a sealed part 25b filled with the pores of this sintered body is installed on the gas inflow side, the gas will pass through and directly hit the semiconductor wafer from the gas inflow side. This means that the problems of the prior art cannot be solved. Therefore, it is necessary to fill the sintered body so that there is no air permeability at least on the gas inlet side.

Note that the pore diameter of the sintered body can be appropriately selected from about 10 μm to 200 μm.

Next, the operation of this heat treatment apparatus will be explained.

First, gas is allowed to flow through the outer tube 24, the camp 30 is opened in the inner tube 25, and the semiconductor wafer 22 mounted on the diffusion board 21 is carried in. In this case, the semiconductor wafer 22 is set so as to be located at the ventilation portion 25a of the internal tube 25 made of a porous SiC sintered body. The inner tube 25 set in this manner is carried in through the cap 31 of the outer tube 24 and accommodated in the outer tube 24.

Therefore, the gas flowing in from the gas inlet 27 is transferred to the external pipe 24.
Gas passes between the inner tube 25 and the inner tube 25 and flows into the inner tube 25 only from the ventilation section 25a made of a porous SiC sintered body. In this case, the gas is uniformly poured from the circumferential direction parallel to the semiconductor wafer 22 as shown by arrows in FIG. 3, slowly circulates around the semiconductor wafer 22, and then is discharged. That is, there is no gas flow in the direction perpendicular to the semiconductor wafer 22 within the inner tube 25, so that the semiconductor wafer 22 is sufficiently exposed to a uniform gas.

In addition, in the diffusion furnace configured as described above, since the opening of the internal tube 25 is completely sealed with the cap 30 on the exhaust side of the external tube 24, the outside air is transferred to the semiconductor wafer 2 in the internal tube 25.
It does not mix into the part 2, and it is possible to prevent variations in diffusion due to the mixing of outside air.

In the above embodiments, the diffusion treatment of semiconductor wafers has been described, but the present invention is not limited thereto, and can be applied to oxidation, annealing, or alloying treatment of semiconductor articles.

Furthermore, the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, there is an external tube into which gas is introduced and exhausted, and a semiconductor article is housed inside the external tube, and the semiconductor article is exposed to the gas. (1) Semiconductor article It is possible to prevent the occurrence of concentration differences in the gas for heat treatment such as diffusion and oxidation, and to supply a uniform gas to semiconductor products, allowing uniform heat treatment to be performed regardless of the location where the semiconductor product is installed. .

(2) Since the furnace core tube has a double structure of an outer tube and an inner tube, outside air does not mix into the inner tube, and it is possible to prevent variations in heat treatment due to outside air mixing.

(3) Focusing on the various characteristics of the porous SiC sintered body described above, especially its excellent chemical stability and mechanical strength, it can be used as a vent for a furnace core tube to achieve stable and long-life heat treatment. equipment can be provided.

As described above, the present invention has various advantages, and the effects brought about by it are remarkable.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a heat treatment apparatus for semiconductor articles according to the present invention, FIG. 2 is a cross-sectional view taken along line n-n' in FIG. 1, and FIG. FIG. 4 is an enlarged structural diagram of a porous SiC sintered body, FIG. 5 is a sectional view of a conventional heat treatment apparatus for semiconductor articles, and FIG. 6 is a sectional view of another conventional heat treatment apparatus for semiconductor articles. 21... Diffusion board, 22... Semiconductor wafer, 2
3... Heater, 24... External tube, 25... Internal tube, 25a... Ventilation part, 25b... Sealed part, 2G...
- Inner tube leg, 27... Gas inlet, 28... Gas piping, 29... Gas system, 30... Inner tube cap, 31... External tube cap, 32... Legs of cap 30, 33...exhaust port.

Claims (2)

[Claims] (1) An outer tube into which a gas is introduced and exhausted, and an inner tube in which a semiconductor article is housed, and where the semiconductor article is exposed to the gas and heat-treated; 1. A heat treatment apparatus for a semiconductor article, characterized in that a ventilation section made of a porous silicon carbide sintered body is provided in a portion of the tube surrounding the semiconductor article. (2) The heat treatment apparatus for a semiconductor article according to claim 1, wherein the porous silicon carbide sintered body has a pore diameter of 10 μm to 200 μm.