JP4139833B2 - Etching method - Google Patents

Description

The present invention relates to an etching processing method , and more particularly to an etching processing method for processing a sample such as a semiconductor element substrate using plasma.

A conventional technique for generating a plasma to process a sample has, for example, a plasma generation chamber in a waveguide that propagates microwaves, as shown in FIG. A plasma is generated in the waveguide by the action of the microwave electric field. Then, the semiconductor wafer substrate is processed using this plasma.

NIKKEI MICRODEVICES August 1990 issue

  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 an etching processing method capable of high-speed wafer processing.

In order to achieve the above-described object, the present invention provides a substrate placed on a sample mounting surface on a sample stage disposed below in a discharge chamber having a substantially circular cross section and supplies a processing gas into the discharge chamber. Then, an electric field is supplied from a means for generating an electric field arranged outside the discharge chamber to generate a plasma from the processing gas, and the plasma is used while applying a high frequency to the sample stage. The discharge chamber is disposed above the sample installation surface above the sample installation surface so as to face the sample installation surface, and is made of an insulator in which the electric field propagates from above into the discharge chamber. A plate member facing the plasma , and the treatment is performed from a supply port arranged in the vicinity of the central axis of the plate member and narrowed down to a region of ¼ or less of the maximum diameter of the discharge chamber. Gas for discharge into the discharge chamber And etching the substrate while reducing the pressure in the discharge chamber by exhausting the processing gas from an exhaust port disposed on the outer peripheral side of the sample table between the sample table and the inner wall of the discharge chamber. It was.

  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 exhausting 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 in 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.

  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 taper 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. Further, the sample stage 12 includes, for example, a temperature control means (not shown), 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 conventional case, and oscillates a microwave of 2.45 GHz, for example. 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. .

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.

  FIG. 4 shows a plan view of another embodiment of the present invention. A gas supply port 17 provided in the quartz plate 18 includes a plurality of small holes 17a. The area where the hole is formed is set to ¼ or less of the maximum diameter of the discharge chamber. By configuring in this way, there is an effect that the gas velocity from the gas supply port 17 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 (1)

A substrate is placed on a sample mounting surface provided on a sample stage disposed inside a discharge chamber having a substantially circular cross section, and a processing gas and a plasma are generated in the discharge chamber using the processing gas in the discharge chamber. And an etching process method for etching the substrate using plasma generated in the discharge chamber and supplying an electric field for generating
The discharge chamber is a plate member made of an insulator which is disposed above the sample installation surface above the sample installation surface and is opposed to the sample installation surface and through which the electric field propagates from above to the discharge chamber. Having a plate member facing
Introducing the processing gas into the discharge chamber from a supply port arranged in the vicinity of the central axis of the plate member and squeezed into a region of ¼ or less of the maximum diameter of the discharge chamber;
From the means for generating an electric field disposed outside the discharge chamber, an electric field is supplied into the discharge chamber to generate plasma from the processing gas, and a high frequency is applied to the sample stage.
Discharging the processing gas from an outlet between the outer peripheral side of the sample stage and the inner wall of the discharge chamber;
Etching treatment of the substrate using the plasma, and a reaction by-product generated on the substrate by the etching treatment is exhausted from the discharge port by the flow of the processing gas. .

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