JPH11312668A - Cleaning method in dry etching device for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a reaction product by applying high-frequency voltage between an electrode plate and a chamber under the state, in which a semiconductor wafer to be dry-etched is not placed on the electrode plate. SOLUTION: The semiconductor wafer, in which a dielectric film is formed on a surface, is replaced with one, in which the dielectric film is not formed on a surface, in the semiconductor wafers placed on the top face of an electrode plate 2. The inside of a chamber 4 is exhausted by a suction by a vacuum pump, etc., from an exhaust port 6 under the state while the inside of the chamber 4 is supplied with a reaction gas from a gas supply pipe 5. High-frequency voltage by a high-frequency power supply 8 is applied between the electrode plate 2 and a base plate 1 or the chamber 4. Consequently, no reaction product from one side of the semiconductor wafer is generated in the chamber 4. Accordingly, the reaction product adhering and depositing on the internal surface of the chamber 4 is gasified and exhausted together with the reactive gas, thus cleaning the reaction product adhering and depositing on the internal surface of the chamber 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a dry etching method for performing dry etching on a dielectric film formed on a surface of a semiconductor wafer used in manufacturing a semiconductor chip.

[0002]

2. Description of the Related Art Conventionally, a dry etching apparatus for performing dry etching on a dielectric film formed on the surface of a semiconductor wafer has been disclosed in Japanese Patent Application Laid-Open No. 50-39676. A semiconductor wafer on which a dielectric film is formed is placed on an upper surface of an electrode plate attached to a base plate via an insulator, while a bell jar is formed on the upper surface of the base plate to cover the entirety of the electrode plate and the semiconductor wafer on the upper surface. A mold chamber is provided, and the inside of the chamber is evacuated by a vacuum pump or the like, while the inside of the chamber is
A reaction gas is supplied from a gas supply pipe, and in this state, a plasma is generated by applying a high-frequency voltage from a high-frequency power source between the electrode plate and the base plate or the chamber, thereby generating plasma cations. Are accelerated and collide with the surface of the semiconductor wafer to etch the dielectric film on the surface of the semiconductor wafer.

[0003]

However, in dry etching using this dry etching apparatus, reaction products accompanying the etching scatter from the semiconductor wafer to the periphery thereof, and most of the reaction products are exhausted from the exhaust port together with the exhaust from the chamber. Although the reaction product is discharged, the remaining part of the reaction product adheres and accumulates on the inner surface of the chamber that covers the entire semiconductor wafer. Falling on the surface of
Defective parts partially occur on the surface of the semiconductor wafer,
Not only does the yield of semiconductor chips significantly decrease, but also the speed of dry etching decreases, and the progress of dry etching cannot be checked.

Therefore, conventionally, when the dry etching is repeated several times, the chamber covering the entire semiconductor wafer is disassembled, and the inner surface thereof is washed with a cleaning liquid to form a reaction product adhered and deposited on the inner surface. The problem is that the efficiency of dry etching is low, and the cost required for dry etching is greatly increased, since the cleaning requires a great deal of labor and time. was there.

An object of the present invention is to provide a cleaning method which solves this problem.

[0006]

In order to achieve this technical object, the present invention provides an electrode plate on which a semiconductor wafer having a film to be dry-etched formed on at least a surface thereof and a cover for covering the semiconductor wafer. A chamber formed in a bell jar type, a high-frequency power supply for applying a high-frequency voltage between the electrode plate and the chamber or base plate, and a means for supplying a reaction gas into the chamber,
In a dry etching apparatus comprising: means for exhausting the inside of the chamber, the chamber is evacuated while a semiconductor wafer to be dry-etched is not mounted on the electrode plate, and a reaction gas is supplied to the chamber. A high-frequency voltage is applied between the plate and the chamber or the base plate. Is the thing.

[0007]

As described above, in the dry etching apparatus, while the semiconductor wafer to be dry-etched is not mounted on the electrode plate, the inside of the chamber is evacuated, and the reaction gas is supplied to the chamber. By applying a high-frequency voltage between the electrode plate and the chamber or the base plate, there is no generation of reaction products from the semiconductor wafer side inside the chamber, so that they adhere and deposit on the inner surface of the chamber. The reaction products that are present are gasified and exhausted together with the reaction gas, so that the inner surface of the chamber can be cleaned so as to remove the reaction products adhered and deposited thereon.

Therefore, according to the present invention, the cleaning of the inner surface of the chamber can be performed in the same manner as ordinary dry etching, so that the number of cleaning operations can be greatly reduced and the cleaning time can be greatly reduced. It is possible to shorten the working efficiency of the dry etching, thereby improving the working efficiency of the dry etching and to reliably reduce the cost required for the dry etching.

In particular, as described in claim 2, by mounting a semiconductor wafer on the surface of which a film that is not dry-etched is formed on the electrode plate, cations are accelerated with respect to the electrode plate. Since the collision can be prevented, the occurrence of corrosion on the electrode plate during the above-described cleaning can be reliably reduced, and there is an advantage that the reduction in durability can be avoided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawing of FIG. In FIG.
Denotes a base plate, and 2 denotes an electrode plate 2 attached to the base plate 1 with an insulator 3 interposed therebetween.
On the upper surface of the base plate 1, a bell-shaped chamber 4 is provided so as to cover the entire electrode plate 2.

A gas supply pipe 5 for supplying a reaction gas into the chamber 4 is provided in the base plate 1.
And an exhaust port 6 from the inside of the chamber 4. When performing a predetermined dry etching, a semiconductor wafer 7 having a dielectric film formed on the upper surface is placed on the upper surface of the electrode plate 2, and then the inside of the chamber 4 is evacuated from a vacuum pump through an exhaust port 6. While a gas is exhausted by suction, etc., a reaction gas is supplied from the gas supply pipe 5 into the chamber 4, and in this state, the electrode plate 2
By applying a high-frequency voltage from the high-frequency power supply 8 to the base plate 1 or the chamber 4, plasma is generated, and positive ions of the plasma are accelerated and collide with the surface of the semiconductor wafer 7. The dielectric film on the surface of the semiconductor wafer is etched.

When the dry etching of the semiconductor wafer 7 is completed in this manner, the base plate 1 provided with the electrode plate 3 is moved downward or the chamber 4 is moved upward to remove the semiconductor wafer 7 after the dry etching. Then, after replacing the semiconductor wafer to be subjected to dry etching, the base plate 1 is moved upward or the chamber 4 is moved downward so that the semiconductor wafer 6 on the upper surface of the electrode plate 2 is covered with the chamber 4. The dry etching is repeated.

When this dry etching is repeated an appropriate number of times, the semiconductor wafer mounted on the upper surface of the electrode plate 4 is changed from a semiconductor wafer having a dielectric film formed on the surface to a dielectric film formed on the surface. In this state, the interior of the chamber 4 is evacuated by suction using a vacuum pump or the like from an exhaust port 6, and a reaction gas is supplied from the gas supply pipe 5 to the interior of the chamber 4. After that, a high-frequency voltage from a high-frequency power supply 8 is applied between the electrode plate 2 and the base plate 1 or the chamber 4.

Then, since no reaction products are generated from the semiconductor wafer side inside the chamber 4, the reaction products adhering and depositing on the inner surface of the chamber 4 are gasified to form a reaction gas with the reaction gas. As a result, the inner surface of the chamber 4 can be cleaned so as to remove the reaction products adhered and deposited thereon.

In this case, since a semiconductor wafer having a dielectric film not formed on the surface thereof is placed on the electrode plate 2, the above-described cleaning requires
Since the cations can be prevented from being accelerated and collided with the electrode plate 2, the occurrence of corrosion in the electrode plate 2 can be surely reduced, and a decrease in durability can be avoided.

Therefore, by performing this cleaning a plurality of times each time the dry etching is performed, the dry etching can be continuously performed for a long time. In the above embodiment, the base plate 1
Is a dry etching apparatus in which the chamber 4 is directly adhered to the upper surface of the substrate to keep the inside of the chamber 4 airtight. However, the present invention is not limited to this type of dry etching apparatus, It is needless to say that the present invention can also be applied to a dry etching apparatus of a type in which a closed box is provided on the upper surface of the substrate and a chamber for covering the electrode plate is provided inside the closed box.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base plate 2 Electrode plate 3 Insulator 4 Chamber 5 Gas supply pipe 6 Exhaust port 7 Semiconductor wafer 8 High frequency power supply

Claims (2)

[Claims] 1. An electrode plate on which a semiconductor wafer having a film to be dry-etched formed thereon is mounted, a chamber formed in a bell jar shape so as to cover the semiconductor wafer, the electrode plate and the chamber or base plate. A high-frequency power supply for applying a high-frequency voltage between the first electrode and the second electrode; a means for supplying a reaction gas into the chamber; and a means for exhausting the gas from the chamber. In a state where the semiconductor wafer having the film to be formed is not mounted, the inside of the chamber is evacuated while a reaction gas is supplied to the chamber, and then a high-frequency voltage is applied between the electrode plate and the chamber or the base plate. Cleaning of semiconductor wafer in dry etching apparatus characterized by the above-mentioned. Method. 2. A method according to claim 1, wherein a semiconductor wafer having a film that is not dry-etched on its surface is mounted on said electrode plate.