JPS6124228A - Vapor growth apparatus - Google Patents

Abstract

PURPOSE:To enable to perform a vapor growth and an etching on a shielding plate simultaneously as well as to grow an excellent semiconductor film having few abnormal grow and contamination by a method wherein an invertable shielding plate is provided on a wafer supporting stand, and etching gas is supplied on the upper surface of the shielding plate. CONSTITUTION:When a semiconductor film is grown on the upper surface of a wafer 21 by performing a vapor growth method, an unnecessary deposit is adhered to the lower surface of a shielding plate 19. The shielding plate 19 is inverted in the next process, and it is placed on retaining plates 18 with the surface, whereon the unnecessary deposit is adhered, facing upward. Besides, a new wafer is placed on the upper surface of a supporting stand 11, a semiconductor film is grown by reaction gas and, at the same time, hydrogen chloride is poured from an etching gas introducing hole 15, and the unnecessary deposit adhered to the upper surface of the shielding plate 19 is removed by etching.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for optically growing a semiconductor film on a semiconductor wafer.

Conventional configurations and their problems There are horizontal, vertical, and barrel types of equipment for vapor phase growth of semiconductor films, but vertical vapor growth equipment has a higher gas flow and temperature than horizontal types. It is easy to control and is often used for growing high-quality semiconductor films.

FIG. 1 shows a cross-sectional view of an example of a conventional vertical vapor phase growth apparatus. In the figure, the earthen wall of a reaction vessel 1 is constructed of a quartz plate 2, and a wafer support 3 is installed inside the reaction vessel 1. Unino 8 is placed on the top surface. The reaction gas is diluted with gear gas and introduced into the reaction container 1 through the gas inlet 6 on the side wall of the reaction container, and the reacted gas is discharged together with the carrier gas from the gas exhaust lower. Reaction vessel 1°
An infrared lamp 4 and a reflector plate 6 are provided above the exterior of the
The sea urchin 8 is heated by an infrared lamp to raise the temperature to the required growth temperature. Then, the introduced reaction gas reacts or decomposes, forming a semiconductor film on the wafer.

However, the introduced reaction gas also heats the soil walls of the reaction container due to thermal radiation and gas convection, and as a result, powder particles are generated and adhered as unnecessary deposits. Therefore, when repeated growth is performed, unnecessary deposits formed on the upper wall of the reaction chamber peel off and fall onto the wafer 8, causing abnormal growth and contamination of the semiconductor film. In addition, infrared rays are absorbed by unnecessary deposits generated on the quartz plate 2 on the upper wall of the reaction vessel, and if the temperature to the sea urchins does not reach the desired value or the layer of unnecessary deposits becomes thick, the expansion coefficient will be different from that of the quartz plate. Unfortunately, there was a problem in that the quartz plate would crack.

Furthermore, there is a problem in that the generated powder passes through the gas exhaust lower and accumulates in the exhaust pipe (not shown), resulting in clogging.

To avoid this situation, after growing multiple times,
For example, the cine deposits may be periodically removed by etching by flowing a gas such as hydrogen chloride (CHGI), but this increases the number of operations and remains a problem.

OBJECTS OF THE INVENTION The present invention provides a vapor phase growth apparatus which eliminates the above-mentioned conventional drawbacks and allows efficient growth of high-quality semiconductor films.

Composition of the Invention The vapor phase growth apparatus of the present invention includes a reaction container, a wafer support provided inside the reaction container, a heating means for heating the wafer support, and a reactor that is reversible above the wafer support. a shielding plate provided to separate the substrate into upper and lower parts, a reactive gas inlet for supplying a reactive gas to the upper surface of the urchin supporter, a reactive gas outlet, and an etching gas inlet for supplying etching gas to the upper surface of the shielding plate. It consists of an opening and an etching gas discharge port, and by inverting the shielding plate, unnecessary deposits attached to the lower surface of the shielding plate due to the growth of the semiconductor film are removed by etching simultaneously with the growth of the semiconductor film.

In the present invention, by feeding the etching gas discharged from the etching gas discharge port into the reaction gas discharge port, it is possible to prevent unnecessary deposits from adhering to the reaction gas discharge pipe.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view of a vapor phase growth apparatus according to an embodiment of the present invention. In the figure, a holder 18 is provided on the upper side wall of the wafer support stand 11 inside the reaction vessel 9, and holds the periphery of a shielding plate 19 made of quartz.

The shielding plate 1e has a rectangular shape so that it can be easily removed, and a projection is provided on the upper surface of the holder 18 to prevent it from falling due to displacement. The reaction vessel is divided into two upper and lower chambers by the holder 18 and the shielding plate 19. An etching gas inlet 15 is provided in the side wall of the upper chamber, and an etching gas outlet is provided in the side wall opposite to the gas inlet 16. 17 are provided. Further, a reaction gas inlet 14 is provided on the side wall of the lower chamber, and a reaction gas outlet 16 is provided at the bottom of the reaction vessel on the opposite side of the wafer support 11. Further, the etching gas exhaust port 17 is connected to the reaction gas exhaust port 16 through a flexible pipe 20, and further communicates with a pipe (not shown) communicating with an exhaust system for processing the exhausted gas.

12 is an infrared lamp as heating means for the wafer support;
13 is a reflecting plate, and 10 is a quartz plate constituting the earthen wall of the reaction vessel.

To explain the operation of the vapor phase growth apparatus having the above configuration, first, the wafer 21 is placed on the upper surface of the wafer support 11, and the temperature of the wafer surface is brought to a desired value using the infrared lamp 12. In vapor phase growth, dichlorosilane S+ is used as the reaction gas.
A semiconductor film was grown on the upper surface of the wafer 21 by using a mixed gas of H2G12 and 7LfH2 and supplying it from the reaction gas inlet 14 at a gas flow rate of 301/min. At this time, unnecessary deposits also adhere to the lower surface of the shielding plate 19. Next, the wafer after the vapor phase growth is taken out and the shielding plate 19 is taken out. At this time, the shielding plate 19 is made into a rectangular shape and can be easily taken out by rotating and tilting it by 90 degrees. Next, the shielding plate 19 is inverted and placed on the holder 18 with the side to which the unnecessary deposits are attached facing upward. Further, a new wafer is placed on the upper surface of the wafer support 11, and a semiconductor film is grown using the reactive gas in the same manner as described above.
From there, hydrogen chloride HOI is flowed to remove unnecessary deposits adhering to the upper surface of the shielding plate 19 by etching. At this time, the flow rate of hydrogen chloride I (Cβ was 1071 per minute),
Hydrogen chloride HCβ is fed into the reaction gas outlet 16 through the flexible pipe 20 to prevent unnecessary deposits from reaching a pipe (not shown) communicating with the gas exhaust system.

If further 1'f growth is to be performed, the above-described operations after taking out the wafer are repeated.

In the above embodiments, hydrogen chloride HOβ was used as the etching gas, but it goes without saying that an appropriate etching gas can be selected depending on conditions such as the type of reaction gas.

Further, in the above embodiment, the shielding plate 19 is reversed every time the vapor phase growth is repeated to remove unnecessary deposits by etching, but depending on the amount of attached unnecessary deposits and other conditions, the vapor phase growth may be repeated multiple times. The shielding plate 19 may be reversed each time the etching is performed.

In addition, in the present invention, if the shielding plate is reversible, the wider the area, the more effective it is;=1, quartz plate.

Stainless steel plate etc. can be used.

Further, the heating means used in the present invention is not particularly limited, and may include resistance heating in addition to infrared lamp heating.

High frequency heating etc. can be used.

Effects of the Invention In this way, the present invention provides a reversible shielding plate above the wafer support and supplies etching gas to the upper surface of the shielding plate, so that vapor phase growth and etching of the shielding plate can be performed simultaneously. It is possible to efficiently grow a high-quality semiconductor film with little abnormal growth or dirt, and its practical effects are great.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an example of a conventional air A''d growth apparatus;
The figure is a sectional view of a vapor phase growth apparatus in one embodiment of the present invention. 11...Wafer support stand, 14...Reaction gas inlet, 16...Etching gas inlet, 19...
...shielding plate, 20...flexible pipe.

Claims (2)

[Claims] (1) Consists of a reaction container, a wafer support provided inside the reaction container, and a heating means for heating the wafer support, which is capable of being turned over above the wafer support and capable of separating the reaction container into upper and lower parts. a shielding plate provided, a reactive gas inlet and a reactive gas outlet for supplying a reactive gas to the upper surface of the wafer support;
A vapor phase growth apparatus comprising an etching gas inlet for supplying etching gas to the upper surface of the shielding plate, and an etching gas outlet. (2) The vapor phase growth apparatus according to claim 1, wherein the etching gas discharged from the etching gas discharge port is introduced into the reaction gas discharge port.