JP2004241783A - Plasma generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma generator capable of high-speed wafer processing with no contamination. <P>SOLUTION: A gas is jetted onto a wafer surface by a discharge chamber 7, a magnetron 1 for generating plasma in the discharge chamber, a waveguide, solenoid coils 10 and 11, a quartz plate 9 for supplying microwaves to the discharge chamber 7, a space for storing gas in the quartz plate 9, and a quartz plate 18 having a gas supply port 17 which is smaller than or equal to a quarter of the maximum diameter of the discharge chamber. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

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

  Conventional microwave generation techniques include, for example, a plasma generation chamber in a microwave-propagating waveguide, as described in NIKKEI MICRODEVICES, August 1990, page 88, FIG. The plasma is generated in the waveguide by the action of an external magnetic field and a microwave electric field. Then, the semiconductor wafer substrate is processed using the plasma.

NIKKEI MICRODEVICES, August 1990, p.88

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

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

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

  Since the generated gas flows through the region of the reaction by-product formed just above the wafer, the reaction by-product is easily exhausted.

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

One 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 invention. The discharge chamber 1 is a magnetron, which is a microwave oscillation source. 3 to 6 are waveguides. Here, 3 is a rectangular waveguide, 4 is a circular waveguide, and 6 is a tapered tube. The discharge chamber 7 is made of, for example, high-purity aluminum or the like, 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, to which a bias power supply, for example, an RF power supply 13 can be connected.
Reference numeral 16 denotes a vacuum pump system for depressurizing and exhausting the inside of the discharge chamber 7 and the inside of the vacuum chamber 8. Reference numeral 15 denotes a gas supply system for supplying a gas for performing processes such as etching and film formation into the discharge chamber 7. A quartz plate 18 having a gas supply port 17 is provided inside the quartz plate 9 of the discharge chamber 7, and a space 19 for storing gas is provided between the quartz plates 9. The distance between the quartz plate 9 and the quartz 18 is set to a small 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 outlet 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 setting 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). The placement of the wafer 14 on the sample placement surface of the sample stage 12 is performed using, for example, a mechanical pressing force or an electrostatic attraction force. The sample stage 12 includes, for example, a temperature control unit (not shown), and the temperature of the wafer 12 installed on the sample installation surface of the sample stage 12 is adjusted to a predetermined temperature by this unit.

  The magnetron is attached to the rectangular waveguide 3 as in the related art, and oscillates, for example, a microwave of 2.45 GHz. On the other hand, the magnetic field distribution is given to the inside of the discharge chamber 7 by the solenoid coils 10 and 11 as shown in FIG. 1B. .

The processing gas passes through the passage 20 from the supply system 15, accumulates in the space 19, and is introduced from the gas supply port 17 into the discharge chamber. The gas is dissociated in the plasma in the discharge chamber 7 to partially become a radical, and processes the surface of the wafer 12. By this surface treatment, reaction by-products scatter into 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. Therefore, the reaction by-products that have entered the stream flow along with the gas stream and are discarded from the outlet 21. 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 from above along the central axis, collides with the wafer 12, and then passes through the surface of the wafer 12. Since the flow goes to the outlet, the reaction by-product is efficiently exhausted from the surface of the wafer 12 to the outlet.

  FIG. 4 shows a plan view of another embodiment of the present invention. The gas supply port 17 provided in the quartz plate 18 is composed of a plurality of small holes 17a. The area where the holes are formed is set to 1/4 or less of the maximum diameter of the discharge chamber. With this configuration, the velocity of the gas from the gas supply port 17 is uniform at each supply port.

FIG. 1 is a block diagram showing a configuration and a magnetic field distribution of a magnetic field type microwave plasma processing apparatus according to an embodiment of the present invention. 1 is a cross-sectional view of one embodiment of the present invention. FIG. 6 is a plan view of another embodiment of the present invention.

Explanation of reference numerals

7: discharge chamber, 9: quartz plate, 12: sample table, 14: wafer, 17: gas supply port, 18: quartz plate, 19: space, 20: passage, 21: discharge port.

Claims (1)

A plasma generating apparatus having a magnetic field microwave plasma, wherein a supply port of a plasma generating gas is arranged on a wall surface of a chamber facing a wafer.

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