JPH02183533A - Contamination preventing method for plasma vapor growth apparatus - Google Patents

Abstract

PURPOSE:To prevent contamination of a chamber inner wall caused by a formation film by installing a cylindrical adhesion preventive plate, which is electrically insulated from the chamber and composed of conductive material, along the inner wall of a plasma reaction chamber, and applying a position DC voltage to the plate at the time of forming a film. CONSTITUTION:A cylindrical adhesion preventive plate 6 which is electrically insulated from the chamber 1 and composed of conductive material is installed along the inner wall of a plasma reaction chamber 15 so as to surround a wafer 3, and a positive DC voltage is applied to the anti-attachment plate 6 at least at the time of forming film. The adhesion preventive plate 6, to which the DC voltage is applied, repels ionized gas and prevents the film from being formed. Thereby, the contamination of the inner wall of the chamber 1 caused by a formation film, which is the particle generation factor of a plasma vapor growth apparatus, can be prevented.

Description

[Detailed Description of the Invention] [Summary] A plasma vapor phase growth apparatus used for manufacturing semiconductor devices,
In particular, regarding methods to prevent contamination of the chamber inner wall, which causes deterioration of the characteristics of the produced film, we will introduce
In order to provide a method for preventing contamination of the inner wall of the chamber by the generated film, a cylindrical anti-adhesion barrier made of a conductive material that is electrically insulated from the chamber is placed along the inner wall of the plasma reaction chamber to surround the wafer. and is configured to temporarily apply a positive DC voltage to prevent deposition at least during film formation.

[Industrial application field]

The present invention relates to a plasma vapor phase growth apparatus used for manufacturing semiconductor devices, and more particularly to a method for preventing contamination of the inner wall of a chamber, which leads to deterioration of the characteristics of a produced film.

In recent years, as the degree of integration of semiconductor devices has increased, patterns have become finer and, for example, it is required that the thickness of the produced insulating protective film be uniform. However, plasma vapor phase epitaxy equipment used to generate insulating protective films sometimes generates a film on the wafer and also on the inner walls of the chamber, and when the film on the inner walls of the chamber becomes thick, fine particles (referred to as particles) are generated. As a result, the uniformity of the thickness of the insulating protective film deposited on the wafer is reduced.

Therefore, it is desired to realize a plasma vapor phase growth apparatus that can efficiently form a film on a wafer to be processed and suppress the formation of a film on the inner wall of a chamber as equipment for manufacturing highly integrated semiconductor devices.

[Conventional technology]

FIG. 3 is a side sectional view showing the main parts of a conventional plasma vapor phase growth apparatus.

In the figure, conventional electron cyclotron resonance (ECR)
The plasma vapor phase growth apparatus (referred to as
1 and a plasma reaction chamber 12, and a magnet coil 2 attached to the outside of the plasma generation chamber 11.

A waveguide 14 is connected to the plasma generation chamber 11 through a microwave introduction window 13, and a stage 4 on which a wafer 3 is placed is provided inside the plasma reaction chamber 12. Note that the gas in the chamber 1 is exhausted from the plasma reaction chamber 12 to the outside via the exhaust pipe 15.

For example, when forming a silicon nitride (SiN) film on the wafer 3, nitrogen gas (N2) is introduced into the plasma generation chamber 11 as a first reaction gas through the pipe 16, and
7, monosilane (Sit14) is introduced into the plasma reaction chamber 12 as a second reaction gas.

In addition, when forming a silicon dioxide (SiO□) film on the wafer 3, oxygen gas (0□) is supplied to the first
5i) I4 is introduced into the plasma reaction chamber 12 as a second reaction gas through the piping 17.

In such a plasma vapor phase growth apparatus, for example, 2
．． Gas (N,
", 02"SrH', etc.) are adsorbed to the wafer 3 together with non-ionized gas and react with each other to form a SiN film or a SiO□ film.

However, chamber 1 is generally made of aluminum, stainless steel, etc., which easily adsorbs gas, so chamber 1 is
The gas that should be adsorbed is also adsorbed on the inner wall of the chamber 1, especially the plasma reaction chamber 12, and a SiN film, a SiO□ film, etc. are generated.

Because the film formed on the inner wall of chamber 1 becomes thick (and the generation of particles increases), it is often necessary to stop the equipment and clean the inner wall of chamber 1. However, cleaning the inner wall of chamber 1 is extremely difficult. This will increase the downtime of the equipment.

Therefore, a cylindrical suction plate 5 made of a conductive material such as aluminum or stainless steel is installed along the inner wall of the plasma reaction chamber 12 so as to surround the wafer 3 to be processed.
The generation of particles is suppressed by frequently replacing the suction plate 5.

[Problem to be solved by the invention]

In the case of conventional plasma vapor phase growth equipment, the film formed on the adsorption plate is removed by self-cleaning using plasma etching technology, but the film formed on the adsorption plate cannot be completely removed and particles are removed. In order to suppress the occurrence, there was a problem in that the device had to be stopped and the suction plate replaced about once every month.

An object of the present invention is to provide a method for preventing contamination of the inner wall of a chamber by a produced film, which is a cause of particle generation in a plasma vapor deposition apparatus.

(Means for Solving the Problems) Fig. 1 is a side sectional view showing an embodiment of the pollution prevention method according to the present invention.The same objects are represented by the same symbols throughout the figures.

The above problem is solved by installing a cylindrical adhesion prevention plate 6 made of a conductive material that is electrically insulated from the chamber 1 so as to surround the wafer 3 along the inner wall of the plasma reaction chamber 12, and at least during film formation. This is achieved by the method for preventing contamination of a plasma vapor deposition apparatus according to the present invention, which applies a direct current voltage of 100 mL to the anti-deposition Fi6.

[Function] In FIG. 1, a cylindrical adhesion prevention plate made of a conductive material and electrically insulated from the chamber is installed along the inner wall of the plasma reaction chamber so as to surround the wafer, and at least during film formation. By applying a positive DC voltage to the deposition prevention plate, the deposition prevention plate to which the positive DC voltage has been applied repels ionized gas and prevents the formation of a film. That is, it is possible to realize a method of preventing contamination of the inner wall of the chamber by the produced film, which is a cause of particle generation in the plasma vapor deposition apparatus.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that FIG. 2 is a perspective view showing an example of the adhesion prevention plate.

An ECR plasma vapor phase growth apparatus incorporating the pollution prevention method of the present invention has a plasma generation chamber 11,
and a chamber 1 having a plasma reaction chamber 12, and a magnet coil 2 attached to the outside of the plasma generation chamber 11.
It is equipped with

A waveguide 14 is connected to the plasma generation chamber 11 through a microwave introduction window 13, and a stage 4 on which a wafer 3 is placed is provided inside the plasma reaction chamber 12. Note that the gas in the chamber 1 is exhausted from the plasma reaction chamber 12 to the outside via the exhaust pipe 15.

Further, a cylindrical deposition prevention plate 6 made of a conductive material and electrically insulated from the chamber 1 is installed in the plasma reaction chamber 12 so as to surround the wafer 3 along the inner wall.
A DC power source 7 provided outside the chamber 1 is connected to the .

This DC power source 7 can vary the voltage between 20 and 100 cm, and when forming a film, a positive DC voltage is applied to the deposition prevention plate 6, but when self-cleaning, the switch 71 is switched. A negative DC voltage can be applied.

The cylindrical deposition prevention plate 6 is made of aluminum, stainless steel, or the like, as shown in FIG. 2, and an insulator 61 for electrically insulating it from the chamber 1 is attached to both ends thereof.

Note that the through hole 62 opened on the side surface of the adhesion prevention plate 6 is a hole into which the piping 17 is inserted.

In such a plasma vapor phase growth apparatus, a first reactant gas and a second reactant gas are introduced into the chamber l through the piping 16 and the piping 17, and a high frequency of 2.45 GHz is introduced through the microwave introduction window 13. By doing this manually, the ionized gas is adsorbed onto the wafer 3 together with the non-ionized gas.

The contamination prevention method of the present invention differs from conventional plasma vapor deposition equipment in that a positive DC voltage of 20 to 100 μ is applied to the deposition prevention plate 6 during film formation, and the ionized gas is repelled to prevent deposition. It will not be attracted to the plate 6. That is, it is possible to realize a method of preventing contamination of the inner wall of the chamber by the produced film, which is a cause of particle generation in the plasma vapor deposition apparatus.

This effect is larger as the ratio of the number of molecules of the total gas to the number of ionized molecules, that is, the ionization rate, is higher, and the ionization rate is greater than in a general RF plasma vapor phase epitaxy device with a low ionization rate (10-' to 10-'). High rate (10-”~10-’)E
The CR plasma vapor phase growth apparatus is more effective.

Gases that cause contamination include ionized gases and non-ionized gases, and gases that are not ionized even when a positive DC voltage is applied to the deposition prevention plate are adsorbed. Therefore, it is not possible to completely eliminate contamination of the deposition prevention plate during film formation, but when applied to an ECR plasma vapor phase epitaxy apparatus, the replacement of the deposition prevention plate is reduced to once every few months, which greatly improves the equipment operation rate. can be increased.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a method for preventing contamination of the inner wall of a chamber by a produced film, which is a cause of particle generation in a plasma vapor deposition apparatus.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the contamination prevention method according to the present invention, Fig. 2 is a perspective view showing an example of an anti-adhesion plate, and Fig. 3 is a main part of a conventional plasma vapor deposition apparatus. This is a side sectional view. In the figure, 1 is a chamber, 2 is a magnet coil, 3 is a wafer, 4 is a stage, 6 is an anti-adhesion plate,
7 is a DC power supply, 11 is a plasma generation chamber, 12 is a plasma reaction chamber, 13 is a microwave introduction window, 14 is a waveguide, 15 is an exhaust pipe, 16.17 is piping, 61
62 represents an insulator, 62 represents a through hole, and 71 represents a switch. A＼＼．≦日月1-7II-RUshishi set up digger, direction; 1 in the center 溪 λ1 row deficit '5 six pull 41J-'I1 ro rise 1 z

Claims (1)

[Claims] A cylindrical adhesion prevention plate (6) made of a conductive material and electrically insulated from the chamber (1) is installed along the inner wall of the plasma reaction chamber (12) so as to surround the wafer (3),
At least during film formation, a positive DC voltage is applied to the deposition prevention plate (
6) A method for preventing contamination of a plasma vapor deposition apparatus, characterized by applying voltage.