JP3732210B2 - Plasma etching equipment - Google Patents

Description

The present invention relates to a microwave plasma generation apparatus, and more particularly to a microwave plasma generation apparatus suitable for increasing the processing speed of a sample such as a semiconductor element substrate using microwave plasma.

Conventional microwave generation techniques include, for example, NIKKEI MICRO
DEVICES) As shown in the August 1990 issue, page 88, FIG. 5, a plasma generation chamber is provided in a waveguide that propagates microwaves, and plasma is generated in the waveguide by the action of an external magnetic field and a microwave electric field. Is supposed to generate. Then, the semiconductor wafer substrate is processed using this plasma.

NIKKEI MICRODEVICES August 1990, page 88

In the above prior art, since the introduction of the process gas is set irrespective of the exhaust of the reaction by-product, the reaction by-product is often reattached to the wafer, and the contamination of the wafer and the reduction in the processing speed become problems. It was.

An object of the present invention is to provide a plasma generation apparatus that can perform high-speed wafer processing without contamination.

In order to achieve the above object, in the present invention, the supply port of the microwave generation gas is opposed to the wafer and concentrated in the center.

Since the product gas flows through a region where reaction by-products formed immediately above the wafer are accumulated, the reaction by-products are easily exhausted.

According to the present invention, reaction by-products generated by wafer processing can be efficiently exhausted, and the processing speed can be increased.

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a magnetic field type microwave plasma processing apparatus. 2 and 3 are a sectional view and a plan view of the present invention. Reference numeral 1 denotes a magnetron, which is a microwave oscillation source. 3-6 are waveguides. Here, 3 is a rectangular waveguide, 4 is a circular rectangular waveguide, 5 is a circular waveguide, and 6 is a tapered tube. The discharge chamber 7 is made of high-purity aluminum or the like, for example, and also serves as a waveguide. 8 is a vacuum chamber. Reference numeral 9 denotes a quartz plate for supplying microwaves to the discharge chamber 7. Reference numerals 10 and 11 denote solenoid coils that apply a magnetic field to the discharge chamber 7. Reference numeral 12 denotes a sample stage on which a semiconductor element substrate (hereinafter referred to as a wafer) 14 is mounted, and a bias power source, for example, an RF power source 13 can be connected thereto.
Reference numeral 16 denotes a vacuum pump system for evacuating the inside of the discharge chamber 7 and the vacuum chamber 8 under reduced pressure. A gas supply system 15 supplies a gas for performing processing such as etching and film formation into the discharge chamber 7. A quartz plate 18 having a gas supply port 17 is installed inside the quartz plate 9 of the discharge chamber 7, and a space 19 for storing gas is provided between the quartz plate 9 and the quartz plate 18. The distance between the quartz plate 9 and the quartz 18 is set to a minute distance so that plasma does not enter. A passage 20 is provided in the side wall 7 ′ of the discharge chamber 7, and the passage 20 communicates with the space 19 and the gas supply system 15. The discharge chamber 7 is provided with a gas discharge port 21 and communicates with the vacuum chamber 8. The size of the gas supply port 17 is set to 1/4 or less of the diameter of the maximum discharge chamber.

In FIG. 1, the sample placement surfaces of the circular waveguide 5, the tapered tube 6, the quartz plate 9, and the sample stage 12 have a coaxial central axis (not shown). Moreover, the installation of the wafer 14 on the sample installation surface of the sample stage 12 is performed using, for example, a mechanical pressing force or an electrostatic adsorption force. Sample stage 12
For example, temperature control means (not shown) is provided, and the temperature of the wafer 12 placed on the sample placement surface of the sample stage 12 is adjusted to a predetermined temperature by this means.

The magnetron is attached to the rectangular waveguide 3 as in the prior art, for example 2.45.
Oscillates GHz microwave. On the other hand, the magnetic field distribution is given in the discharge chamber 7 by the solenoid coils 10 and 11 as shown in FIG. 1B, and the place where the ECR point (875 gauss) is set is set near the center of the discharge chamber. .

The processing gas passes from the supply system 15 through the passage 20, accumulates in the space 19, and is introduced into the discharge chamber from the gas supply port 17. The gas is dissociated in the plasma in the discharge chamber 7 to become a part of radicals, and the surface of the wafer 12 is processed. By this surface treatment, reaction by-products are scattered in the discharge chamber 7. The gas flow in the discharge chamber 7 is formed so as to go from the gas supply port 17 to the discharge port 21. Accordingly, the reaction by-product that has entered the flow rides on the gas flow, and the discharge port 21.
Discarded from. However, reaction by-products tend to accumulate on the source wafer 12. According to this embodiment, since the gas supply port is narrowed to the center of the discharge chamber 7, the gas descends along the central axis from above and collides with the wafer 12 and then passes through the surface of the wafer 12. Since it goes to the discharge port, the reaction by-product is efficiently exhausted from the surface of the wafer 12 to the discharge port.

Another embodiment of the present invention will be described. In this embodiment, a gas supply port provided on a quartz plate is made from a plurality of small holes. The area where the hole is formed is set to ¼ or less of the maximum diameter of the discharge chamber. By comprising in this way, there exists an effect which the velocity of the gas from a gas supply port becomes uniform in each supply port.

The block diagram which shows the structure and magnetic field distribution of a magnetic field type | mold microwave plasma processing apparatus which show one Example of this invention. Sectional drawing of one Example of this invention. The top view of one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 7 ... Discharge chamber, 9 ... Quartz plate, 12 ... Sample stand, 14 ... Wafer, 17 ... Gas supply port, 18 ... Quartz plate, 19 ... Space, 20 ... Passage, 21 ... Discharge port

Claims (6)

A discharge chamber in which plasma is generated , and
Decompression means for decompressing the discharge chamber;
A sample stage having a sample setting surface on which the sample is placed and placed in the discharge chamber;
Means for generating an electric field for generating plasma provided outside the discharge chamber;
A high frequency power source for applying a high frequency to the sample stage;
A plate member made of an insulator that is disposed facing and facing the sample installation surface above the sample installation surface of the discharge chamber, and the electric field propagates from above to the sample installation surface direction;
A supply port that is provided in the plate member and is arranged in the vicinity of the central axis of the discharge chamber, and a processing gas is supplied into the discharge chamber;
The supply port is disposed in a region of ¼ or less of the maximum diameter of the discharge chamber;
A plasma etching apparatus in which the processing gas is exhausted from an outer peripheral side of the sample stage. 2. The plasma according to claim 1 , wherein a gas flow capable of exhausting reaction by-products generated on the surface of the sample by processing with the plasma is formed by supplying a processing gas from the supply port. Etching equipment. That the flow of the processing gas is arranged to be discharged from between the inner wall of the discharge chamber periphery and the discharge chamber along the central axis descends within the discharge chamber of the sample stage from the supply port The plasma etching apparatus according to claim 1, wherein the plasma etching apparatus is a plasma etching apparatus. The plasma etching apparatus according to any one of 3 claims 1, wherein the insulator made of the plate member is a quartz plate. A substantially cylindrical discharge chamber in which plasma is generated , and
A sample stage having a sample setting surface on which a sample is placed under the discharge chamber and near the center of the discharge chamber;
Means for generating an electric field for generating plasma provided outside the discharge chamber;
A high frequency power source for applying a high frequency to the sample stage;
A plate member made of an insulator, which is disposed so as to face the sample installation surface and in contact with the plasma above the sample installation surface of the discharge chamber, and in which the electric field propagates from above to the sample installation surface;
A supply port for the arranged concentrates near the center axis of the discharge chamber process gas provided in the plate member is supplied to the discharge chamber,
A vacuum pump system for depressurizing the discharge chamber,
The supply port is disposed in a region of ¼ or less of the maximum diameter of the discharge chamber;
The processing gas introduced into the discharge chamber flows from the supply port toward the outer periphery of the sample table, and is discharged from between the outer periphery of the sample table and the inner wall of the discharge chamber. Plasma etching equipment. 6. The plasma according to claim 5 , wherein a gas flow capable of exhausting reaction by-products generated on the surface of the sample by processing with the plasma is formed by supplying a processing gas from the supply port. Etching equipment.

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