JPH06132275A - Gas feeder in multiple-gas reaction type surface processor - Google Patents

Abstract

PURPOSE:To equalize the film ingredients in the thickness direction of a film, and easily control the thickness of the film, and lessen the dispersion of film thickness with every batch operation, in case of forming a film on a silicon wafer by supplying the reaction gas from a plurality of reaction gas supply through gas supply pipes into a processing chamber containing a silicon water. CONSTITUTION:A purge pipe 7, which is arranged so as to discharge the reaction gas from each reaction gas supply pipe 4 and 5 to outside of a gas supply pipe 2, is connected to the gas supply pipe 2 to a processing chamber 1, and also a changeover means is provided for selectively changing over the state between the first state, which lets the reaction gas from each reaction gas supply pipe 4 and 5 flow to the purge pipe 7, and the second state, which supplied it to the processing chamber 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when manufacturing a semiconductor chip, forms various thin films on the upper surface of a silicon wafer by the reaction of various kinds of gas such as forming an oxide film by the reaction of hydrogen gas and oxygen gas. When performing surface treatment by reaction of many kinds of gas, such as forming or etching of silicon nitride by reaction of many kinds of gas, supply many kinds of gas into the processing chamber. It is related to the device.

[0002]

2. Description of the Related Art Conventionally, an oxide film forming apparatus for thermal oxidation using water vapor, among surface treating apparatuses of this type using a large number of gases, is a processing in which a silicon wafer (not shown) is accommodated as shown in FIG. The external combustion chamber C is connected to the gas supply pipeline B to the chamber A, and the hydrogen gas supply pipeline D, the oxygen gas supply pipeline E and the nitrogen gas supply pipeline F are connected to the external combustion chamber C, First, by supplying the nitrogen gas from the nitrogen gas supply pipeline F into the processing chamber A through the gas supply pipeline B, the inside of the processing chamber A is filled with the nitrogen gas atmosphere, and then the external combustion chamber C. By supplying hydrogen gas from the hydrogen gas supply pipeline D and oxygen gas from the oxygen gas supply pipeline E to the inside of the processing chamber A. By supplying the liquid through the path B, So that an oxide film is formed on the surface of the N'ueha.

[0003]

However, when the hydrogen gas from the hydrogen gas supply line D and the oxygen gas from the oxygen gas supply line E are supplied, these two reaction gases are initially converted into steam. It is impossible to supply a predetermined amount necessary for production, and a certain rise time is required until the predetermined amount is reached and a stable flow rate is reached. If it precedes supply, it may explode.

Therefore, conventionally, the supply of oxygen gas is preceded, and after the supply of oxygen gas reaches a predetermined amount, the supply of a predetermined amount of hydrogen gas is started. as a result,
Oxygen gas is first supplied to the processing chamber within the rising time of oxygen gas, and then a mixed gas of oxygen gas and hydrogen gas is supplied within the time of incomplete combustion within the rising time of hydrogen gas, and Since the water vapor is supplied by the complete combustion of oxygen gas and hydrogen gas and the formation of the oxide film proceeds by the supply of the oxygen gas and the supply of the mixed gas, the film components are distributed in the thickness direction of the film. There is a problem that it will be different along the line, and it is extremely difficult to control the film thickness to a predetermined value,
There is also a problem that a large variation occurs in the film thickness for each batch operation.

Also, when a CVD thin film of silicon nitride (SiN) is formed by the plasma reaction of SiH ₄ gas and NH ₃ gas, a predetermined mixing ratio is achieved due to the existence of the rising time when the various reaction gases are supplied. The same problem as described above occurs due to the supply of a mixed reaction gas that does not exist, and furthermore, etching of silicon nitride (SiN) by a plurality of kinds of reaction gases such as CF ₄ gas, CBrF ₃ gas and oxygen gas. In this case, there is a problem that uneven etching and excess / deficiency of etching occur due to the supply of a mixed gas that does not have a predetermined mixing ratio due to the rising time at the time of supplying various reaction gases.

SUMMARY OF THE INVENTION The present invention has a technical object to provide a gas supply device in which these problems do not occur.

[0007]

In order to achieve this technical object, the present invention provides a multi-gas reaction type surface treatment apparatus in which a plurality of reaction gas supply pipes are connected to a gas supply pipe into the processing chamber. In the portion of the gas supply pipe to the processing chamber on the downstream side of the connection portion of each reaction gas supply pipe line, the reaction gas from each reaction gas supply pipe to the outside of the gas supply pipe. A first state in which the purge gas lines adapted to release the gas are connected, and the reaction gas from each of the reaction gas supply lines flows into the purge line and the second state in which the reaction gas is supplied to the processing chamber.
The switching means for selectively switching to the above state is provided.

[0008]

[Operation] In this configuration, when supplying the reaction gas from each reaction gas supply pipe, first, the switching means,
By setting the first state, all the reaction gas supplied from each reaction gas supply pipeline is discharged from the purge pipeline without being supplied to the processing chamber.

Therefore, when the rising time at the time of supplying the reaction gas from each of the reaction gas supply pipes elapses and the supply amount reaches a predetermined amount and becomes stable,
By switching the switching means to the second state,
A mixed gas having a predetermined mixing ratio can be stably and continuously supplied into the processing chamber.

[0010]

Therefore, according to the present invention, when various reaction gases are supplied to the processing chamber, an unstable rising time elapses at the start of the supply, and various reaction gases from the respective reaction gas supply pipelines are supplied. Since it can be performed after the supply amount is stable, when forming a thin film such as an oxide film, the film components can be made uniform in the film thickness direction, and the film thickness can be easily controlled. Furthermore, it is possible to reduce variations in film thickness between batch operations.

Further, in the etching process, it is possible to reliably reduce the occurrence of etching unevenness and the occurrence of excess or deficiency of etching.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drawing (FIG. 1) in which an embodiment of the present invention is applied to an oxide film forming apparatus for thermal oxidation with steam will be described below. In this figure, reference numeral 1 indicates a processing chamber accommodating a plurality of silicon wafer (not shown) films.
Are respectively gas supply pipelines into the processing chamber 1. An external combustion chamber 3 is connected to the gas supply pipeline 2 and a hydrogen gas supply pipeline provided with a valve 4a is provided in the external combustion chamber 3. 4 is connected to the oxygen gas supply line 5 which is also provided with the valve 5a.

On the other hand, the gas supply pipe 2 is provided with a valve 6 in the middle thereof, and a valve 7 is provided at a portion upstream of the valve 6.
The purge line 7 having a is connected to the downstream side of the valve 6 to the nitrogen gas supply line 8 having a valve 8a. In this configuration, the valve 6 in the gas supply line 2
When the valve 8a in the nitrogen gas supply line 8 is opened in the closed state, the nitrogen gas is supplied from the nitrogen gas supply line 8 into the processing chamber 1 containing a plurality of silicon wafers (not shown) in advance. By supplying the gas, the inside of the processing chamber 1 is made an atmosphere of nitrogen gas.

Next, the valve 8a in the nitrogen gas supply line 8 is closed, the valve 7a in the purge line 7 is opened, and then the valve 5a in the oxygen gas supply line 5 is opened to open the external combustion chamber. When the supply of oxygen gas to 3 is started, this oxygen gas is discharged from the purge line 7 without being supplied to the processing chamber 1. Therefore, the valve 4a in the hydrogen gas supply conduit 4 is opened and hydrogen gas is supplied to the external combustion chamber 3 for combustion after a suitable delay in the supply of the oxygen gas. The gas of complete combustion is discharged from the purge line 7 without being supplied to the processing chamber 1.

When the combustion of oxygen gas and hydrogen gas in the external combustion chamber 3 becomes stable, the valve 6 in the gas supply line 2 is opened while the valve 7a in the purge line 7 is opened. As a result, a predetermined amount of water vapor can be continuously supplied into the processing chamber 1 in a stable state, so that the formation of the oxide film on the surface of the silicon wafer can be started from this point.

In the above embodiment, the valves 6 and 7a are provided in both the gas supply line 2 and the purge line 7 to allow the reaction gas to flow in the purge line 7 in the first state and the process. Although the case of selectively switching to the second state in which the gas is supplied to the chamber 1 is shown, as shown in FIG. 2, a three-way switching valve 9 is provided at the connection portion of the purge line 7 to the gas supply line 2. The three-way switching valve 9 allows the reaction gas to flow in the purge line 7 in the first state and the processing chamber 1 to supply the second state.
It may be configured to selectively switch to the above state.

Further, the present invention is not limited to the formation of an oxide film by oxygen gas and hydrogen gas as in the above-mentioned embodiment, and for example, the formation of a CVD thin film by SiH ₄ gas and NH ₃ gas,
Alternatively, it goes without saying that the same can be applied to etching with CF ₄ gas, CBrF ₃ gas, oxygen gas and the like.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing another embodiment of the present invention.

FIG. 3 is a vertical sectional front view showing a conventional example.

[Explanation of symbols]

 1 Processing Chamber 2 Gas Supply Pipeline 3 External Combustion Chamber 4 Hydrogen Gas Supply Pipeline 5 Oxygen Gas Supply Pipeline 6 Valve 7 Purge Pipeline

Claims (1)

[Claims] 1. A multi-gas reaction type surface treatment apparatus comprising a gas supply pipe into the processing chamber and a plurality of reaction gas supply pipes connected to the reaction chamber. A purge pipe line for releasing the reaction gas from each of the reaction gas supply pipes to the outside of the gas supply pipe is connected to a site downstream of the connection portion of the gas supply pipe, and each reaction A switching means is provided for selectively switching between a first state in which the reaction gas from the working gas supply pipeline is supplied to the purge pipeline and a second state in which the reactive gas is supplied to the processing chamber. Gas supply device for gas reaction type surface treatment equipment.