JPS6281018A - Normal pressure cvd device - Google Patents

Abstract

PURPOSE:To improve the yield of a normal pressure CVD device by horizontally feeding reaction gas to a semiconductor wafer surface, thereby preventing the wafer from damaging by a reaction product. CONSTITUTION:Two dispersion heads 1 are opposed to each other, and horizontally mounted on a semiconductor wafer 5 surface. Thus, reaction gas is supplied from a reaction gas suction port 10 to flow through the heads 1 along the wafer 5 moving on a tray 4, and exhausted through a gas exhaust passage 11. Since the passage 11 can be shaped smooth, an exfoliation can be suppressed to prevent a reaction product from locally accumulating and to prevent the product from dropping on the wafer 5 or the wafer 5 from damaging due to the contact with the product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an atmospheric pressure CVD apparatus suitable for introducing a reaction gas.

[Background of the invention]

FIG. 1 shows the basic overall configuration of a typical conventional atmospheric pressure CVD apparatus. In the normal pressure CVD apparatus, a semiconductor wafer 5 is placed on a movable tray 4 and passed under two dispersion heads 1 to form a desired thin film on the semiconductor wafer 5. . FIG. 2 shows details of the dispersion head 1. As shown in the second @, the reactive gas (PHa, S i Ha
) is ejected from below the dispersion head 1 onto the semiconductor wafer 5 while causing a reaction, as shown by the arrow. As a result, a thin film is formed on the semiconductor wafer 5, and a large amount of reaction products (solid fine particles of SiOx) are generated. In addition, not all of the reactive gas that has flowed into the reactor undergoes a reaction, but some unreacted gas remains. This unreacted gas and reaction products are forcibly discharged to the outside from an exhaust port 8 through a discharge channel 7 formed by the dispersion head 1 and head cover 3 by a suction pump (not shown) provided externally. Ru. The details of the gas flow are shown in Figure 3.As shown in Figure 3, in order to prevent unreacted gas and reaction products from leaking outside through the gap between the hem of the head cover 3 and the tray 4, External air is sucked in from the hem of the head cover 3 along with the reaction gas and reaction products. Therefore, the unreacted gas will newly react with oxygen in the air, and further reaction products will be generated. As a result, these reaction products 9 are deposited in large quantities on the head cover 3 and the corners of the dispersion head 1, as shown in FIG. This deposited reaction product 9 is transferred to a semiconductor wafer 5 which passes under the dispersion head 1 on a tray 4.
fall on top. Further, as the deposition progresses, the semiconductor wafer 5 and the deposited reaction product 9 come into contact. Due to these things,
The semiconductor wafer 5 is damaged and the yield of the semiconductor wafer 5 in the CVD process is reduced. In order to prevent this decline, the reaction products are removed periodically. Therefore, there is a problem that the operating rate decreases.

As an example of this solution, nitrogen gas is ejected in the form of a sheet through a large number of micropores from the wall surface of the area where reaction products tend to accumulate. It is thought that by doing this, the adhesion of reaction products to the wall surface can be prevented to some extent, but it is not completely possible.

Furthermore, this method is not considered to be very practical because of problems such as the structure of the dispersion head 1 becoming complicated and the micropores becoming clogged. In addition, for those related to this type of equipment,
There is No. 46056.

(Objective of the Invention) The object of the present invention is to improve the yield of semiconductor wafers by preventing as much as possible damage to semiconductor wafers due to reaction products in the CVD process, and to reduce the number of times the reaction product removal work is required. An object of the present invention is to provide a CVD device that facilitates inspection work.

[Summary of the invention]

The gas flow in the discharge channel of the conventional device was analyzed by numerical calculation. The results are shown in FIG.

Since the location where the flow of unreacted gas is separated in the discharge channel 7 and the location where reaction products are deposited in the actual device match, reducing the separation area This is thought to help prevent the accumulation of Therefore,
The present invention is composed of a dispersion head for ejecting a reaction gas onto a semiconductor wafer, and a head cover for preventing the reaction gas from leaking to the outside and forming an exhaust flow path for reaction products and unreacted gas. In the atmospheric pressure CVD apparatus, the reactant gas is configured to flow horizontally to the semiconductor wafer surface,
This is designed to achieve the above purpose.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIG. Fifth
As shown in the figure, two dispersion heads 1 are placed facing each other in a horizontal direction with respect to the surface of a semiconductor wafer 5. Therefore, the reactive gas is supplied from one reactive gas inlet 10, passes through the dispersion head 1, flows along the surface of the semiconductor wafer 5 moving on the tray 4, and is discharged to the outside through the gas exhaust channel 11. be done.

By adopting such a structure, the gas exhaust channel 11 can be formed into a smooth shape, so that occurrence of peeling can be suppressed and local accumulation of reaction products can be prevented. Therefore, it is possible to prevent damage to the semiconductor wafer 5 due to reaction products falling onto or touching the semiconductor wafer 5, which occurs in conventional apparatuses, and thus the yield in the CVD process can be improved.

In addition, since the number of times of removal work for one reaction product can be reduced, there is a great effect of improving the operating rate of the CVD apparatus.

〔Effect of the invention〕

According to the present invention, it is possible to prevent local deposition of reaction products in the CVD apparatus, thereby improving the yield in the CVD process of semiconductor wafers and reducing the operating rate of the CVD apparatus due to the removal work of the reaction products. It has the effect of preventing

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of the atmospheric pressure CVD apparatus, and FIG. 2 is a C
3 is a longitudinal sectional view of the dispersion head of the VD device, FIG. 4 is an explanatory diagram of the analysis results of gas flow, and FIG. 5 is a longitudinal sectional view of the embodiment of the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1...Dispersion head, 3...Head cover, 4...Tray, 5...Semiconductor wafer, 9...
reaction product. 10... Intake port, 11... Discharge channel. 'Az diagram f 3 diagram

Claims (1)

[Claims] A conventional device consisting of a dispersion head for ejecting a reaction gas onto a semiconductor wafer, and a head cover for preventing the reaction gas from leaking to the outside and forming an exhaust channel for reaction products and unreacted gas. 1. An atmospheric pressure CVD apparatus, characterized in that the reactant gas is introduced horizontally to the surface of a semiconductor wafer.