JPH07201837A - Apparatus for manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to apply a reactive gas uniformly to a surface of a semiconductor wafer, by separating a first space, in which semiconductor wafers are arranged, and a second space, in which a reactive gas is supplied, and diffusing the gas through a porous plate from the second space to the first space. CONSTITUTION:In a semiconductor manufacturing apparatus 20, a flange of quartz glass is formed on an inner circumferential face of an inner tube 3. A porous plate 22 having a plurality of through holes 23 of 1mm or above in diameter is fixed around a quartz cap 6. The flow of a reactive gas through a nozzle 7 into a double reactive tube 8 is blocked by the porous plate 22, and the reactive gas can not diffuse immediately into a wafer-boat arranged space 25A and remains still in a nozzle arranged space 25B. After a while, the reactive gas, which is increasing in the space 25B, diffuses into the wafer- boat 4 arranged space 25A uniformly through the through holes 23 of the porous plate 22. In this way, the reactive gas is applied uniformly to a wafer 5, and thereby the an insulating film is formed uniformly in thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus,
For example, chemical vapor deposition
on)) It is suitable to be applied to a device.

[0002]

2. Description of the Related Art Conventionally, vertical low pressure CVD (chemical vapor deposition)
2. Description of the Related Art A type semiconductor manufacturing apparatus has a structure as shown in FIG. That is, in FIG. 4, reference numeral 1 denotes a semiconductor manufacturing apparatus as a whole, and a boat 4 is installed in a double reaction tube 8 constituted by an outer tube 2 and an inner tube 3 with a quartz cap 6 as a pedestal. A plurality of wafers 5 are accommodated in the boat 4 in a stacked state at a predetermined interval.

A plurality of nozzles 7 are provided inside the double reaction tube (2, 3) having such a structure, and a tetraethoxy ozosilane (hereinafter referred to as TEOS) type reaction gas is supplied through the nozzles 7. By being introduced into the double reaction tube 8, an insulating film is formed on the wafer surface by the reaction gas.

[0004]

By the way, in the semiconductor manufacturing apparatus 1 having such a structure, when the reaction gas GA is introduced into the double reaction tube 8 as shown in FIG. 5, the diffusion characteristic of the reaction gas GA is bad. , Will be unevenly diffused over the boat 4. As a result, there is a problem that the thickness of the insulating film 5A formed on the surface of the wafer 5 becomes uneven as shown in FIG.

As one method for solving this problem, a plurality of nozzles 7 for introducing the reaction gas into the double reaction tube 8 are arranged and the reaction gas GA is injected from a plurality of injection sources. Therefore, the reaction gas G in the double reaction tube 8
A method of making the diffusion of A uniform is considered.

However, in such a structure, there is an unavoidable problem that the structure of the semiconductor manufacturing apparatus 1 is complicated as a whole because a plurality of nozzles 7 are arranged.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose a semiconductor manufacturing apparatus capable of uniformly diffusing a reaction gas and adhering it uniformly to the surface of a semiconductor wafer with a simple structure. To do.

[0008]

In order to solve such a problem, in the present invention, a semiconductor manufacturing apparatus 20 for forming an insulating oxide film 5A on the surface of a semiconductor wafer using a reaction gas GA.
In the above, the semiconductor wafer 5 is placed inside, and a housing 8 for adhering the reaction gas GA to the semiconductor wafer 5 by introducing a predetermined reaction gas GA;
Is divided into a first space 25A in which is arranged and a second space 25B into which the reaction gas GA is introduced, and a porous plate 22 in which a plurality of through holes 23 are formed is provided.
The reaction gas GA introduced into B is made to diffuse into the first space 25A through the plurality of through holes 23 of the porous plate 22.

Further, in the present invention, the reaction gas GA is
A mixture of tetratoxiosilane or a silane-based gas and a predetermined doping gas is used.

Further, in the present invention, the through hole 23 has a diameter of 1 mm or more, and the edge formed on the surface of the porous plate and the connecting portion of the through hole 23 is curved.

Further, in the present invention, the through hole 23 and the perforated plate 22 form a silicon film 27 on the surface.

[0012]

By diffusing the reaction gas GA introduced into the second space 25B into the first space 25A in which the semiconductor wafer is arranged through the plurality of through holes 23 of the porous plate 22,
The diffusion of the reaction gas GA in the first space 25A can be made uniform.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 4 are designated by the same reference numerals, a flange 21 made of quartz glass is formed on the inner peripheral surface of the inner tube 3 in the semiconductor manufacturing apparatus 20. On the outer peripheral surface of the quartz cap 6, a perforated plate 22 of quartz glass, in which a plurality of through holes 23 having a diameter of 1 [mm] or more are arrayed, is formed on the lower surface of the flange 21 by about 3 to 5 [mm]. It is fixed across a gap. Therefore, double reaction tube 8
The inside is divided by the porous plate 22 into a boat arrangement space 25A in which the board 4 is arranged and a nozzle arrangement space 25B in which the nozzles 7 are arranged.

As shown in FIG. 2, the perforated plate 22 has a plurality of through holes 23 formed along the outer peripheral surface of the quartz cap 6, and is introduced from the nozzle 7 into the double reaction tube 8 through the through holes 23. The reaction gas can be introduced between the nozzle arrangement space 25B and the boat arrangement space 25A. Here, the reaction gas is a mixture of TEOS or silane (SiH ₄ ) based gas with a doping gas such as B (C ₂ H ₅ ) ₃ , PO (CH ₃ ) ₃ , PH ₃ or B ₂ H _6. To use.

Here, in the porous plate 22, as shown in FIG. 3 (A), by forming an insulating film by a reaction gas on the entire surface of the through hole 23 and the porous plate 22, the through hole 23 can be used for a long time. This may cause clogging. Therefore, Figure 3
As shown in (B), the through hole 23 is annealed to form a curved surface (round) in the edge portion, and silicon of about 10 to 20 [μm] is formed on the entire surface of the porous plate 22 including the through hole 23. By forming a silicon film 27 by depositing (Poly-Si), it is difficult to form an insulating film, and the selection ratio between the insulating film and the silicon film is large even in the regular etching of quartz parts. Therefore, the base is protected and the shape during processing can be maintained.

In the above structure, the reaction gas introduced from the nozzle 7 into the double reaction tube 8 is not immediately diffused into the boat arrangement space 25A because the porous plate 22 is provided, and the nozzle arrangement space 25B is not immediately diffused. Stay in. At this time, the reaction gas slightly flows out from the through hole 23 formed in the porous plate 22 into the boat arrangement space 25A, but the outflow amount is a minute amount compared with the amount of the reaction gas accumulated in the nozzle arrangement space 25B.

When the reaction gas accumulates in the nozzle arrangement space 25B, the reaction gas diffuses into the boat arrangement space 25A from the through hole 23 formed in the porous plate 22 using the nozzle arrangement space 25B as a diffusion source of the reaction gas. .

As a result, the reaction gas uniformly diffuses into the boat arrangement space 25A from the through holes 23 surrounding the board 4 below the boat 4, so that the reaction gas with respect to the wafers 5 accommodated in the boat 4 can be obtained. Adheres evenly. Thus, the thickness of the insulating film formed by the reaction gas on the surface of the wafer 5 becomes uniform.

According to the above construction, by disposing the perforated plate 22, the inside of the double reaction tube 8 is provided with the boat arrangement space 25.
A and the nozzle arrangement space 25B are divided, and the reaction gas accumulated in the nozzle arrangement space 25B is diffused into the boat arrangement space 25A through the plurality of through holes 23 arranged in the porous plate 22. The diffusion of the reaction gas into the board disposing space 25A can be made uniform,
As a result, the thickness of the insulating film 5A formed on the wafer 5 housed in the boat 4 can be made uniform.

In the above embodiment, the case where the present invention is applied to the vertical type semiconductor manufacturing apparatus 20 has been described, but the present invention is not limited to this, and a horizontal type semiconductor manufacturing in which the board 4 is arranged in the horizontal direction is used. The present invention can be applied to an apparatus.

[0022]

As described above, according to the present invention, a boat arrangement in which a boat for holding a semiconductor wafer is arranged inside a double reaction tube for forming a film of tetratoxiozosilane or silane on the surface of the semiconductor wafer. The space and the nozzle arrangement space for introducing the reaction gas are divided by a perforated plate having a plurality of through holes, and the reaction gas introduced from the nozzle into the double reaction tube is temporarily stored in the nozzle arrangement space. Since the reaction gas accumulated in the nozzle arrangement space is uniformly diffused into the boat arrangement space through the through holes of the perforated plate, the reaction gas can be uniformly attached to the surface of the semiconductor wafer. Thus, the thickness of the film-forming layer formed on the surface of the semiconductor wafer can be made uniform.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a semiconductor manufacturing apparatus according to the present invention.

FIG. 2 is a perspective view showing a configuration of a perforated plate according to the present invention.

FIG. 3 is a cross-sectional view showing the structure of a through hole.

FIG. 4 is a sectional view showing a conventional semiconductor manufacturing apparatus.

FIG. 5 is a cross-sectional view showing a non-uniform diffusion state of a reaction gas.

FIG. 6 is a cross-sectional view showing a non-uniform state of an insulating layer formed on the surface of a wafer.

[Explanation of symbols]

1, 20 ... Semiconductor manufacturing equipment, 2 ... Outer tube,
3 ... Inner tube, 4 ... boat, 5 ... wafer,
5A ... film forming layer (insulating layer), 6 ... quartz cap, 7 ...
… Nozzle, 8 …… Double reaction tube, 21 …… Flange, 22
…… Perforated plate, 23 …… Through hole, 27 …… Silicon film.

Claims (4)

[Claims] 1. A semiconductor manufacturing apparatus for forming an insulating oxide film on a surface of a semiconductor wafer by using a reaction gas, wherein the semiconductor wafer is placed inside, and a predetermined reaction gas is introduced into the semiconductor wafer to cause the reaction. A housing for adhering gas, a housing for dividing the housing into a first space in which the semiconductor wafer is arranged, and a second space for introducing the reaction gas, and a perforated plate having a plurality of through holes formed therein. The semiconductor manufacturing apparatus according to claim 1, wherein the reaction gas introduced into the second space is diffused into the first space through a plurality of through holes of the porous plate. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the reaction gas is a mixture of tetratoxiozosilane or a silane-based gas and a predetermined doping gas. 3. The through hole having a diameter of 1 [mm] or more, and the edge formed on the surface of the perforated plate and the connecting portion of the through hole is curved to form a curved surface. Semiconductor manufacturing equipment. 4. The semiconductor manufacturing apparatus according to claim 1, wherein the through-hole and the perforated plate have a silicon coating formed on the surface thereof.