JPH10229074A - Microwave plasma etching equipment - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a microwave plasma etching apparatus capable of suppressing a decrease in an etching rate of an oxide film in etching an oxide film and obtaining a high selectivity with an underlying silicon film. That is. [Constitution] In a microwave plasma etching apparatus,
Silicon carbide is used for a constituent member of the vacuum vessel 4 for generating plasma, for example, the electrode cover 10, and high-frequency power is applied to the silicon carbide. [Effect] A decrease in the etching rate of the oxide film is suppressed, and a high selectivity with respect to the underlying silicon film can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave plasma etching apparatus for etching an oxide film with plasma generated by a magnetic field and a microwave electric field, which is suitable for obtaining a high selectivity with respect to an underlying silicon film. The present invention relates to a microwave plasma etching apparatus.

[0002]

2. Description of the Related Art A conventional microwave plasma etching apparatus is described in, for example, Hitachi Review Vol. 71 (1989), N
o. As described in 5, P33-38, a discharge tube made of quartz is provided in a waveguide for propagating microwaves, and plasma is generated in the discharge tube by the action of an external magnetic field and a microwave electric field. Is to be etched.

[0003]

In the conventional apparatus, consideration is not always given to the influence on the etching characteristics of the members constituting the vacuum vessel for generating plasma, particularly on the selectivity with the underlying silicon film. There was a problem that the etching rate of the oxide film was reduced in order to obtain a selectivity with respect to the underlying silicon film.

An object of the present invention is to provide a microwave plasma etching apparatus capable of suppressing a decrease in an etching rate of an oxide film in etching an oxide film and obtaining a high selectivity with respect to an underlying silicon film.

[0005]

In order to achieve the above object, silicon carbide is used as a member constituting a vacuum vessel, and high-frequency power is applied to the silicon carbide.

[0006]

When silicon carbide is used as a member constituting a vacuum vessel and high-frequency power is applied to the silicon carbide, silicon (silicon) or carbon, which is a component of silicon carbide, is sputtered. In addition, carbon fluoride is generated by a reaction with fluorine ions present in the plasma. The reaction with the sputtered silicon (silicon) or carbon reduces fluorine ions or fluorine atoms, which are reactive species of silicon, and decreases the etching rate of the underlying silicon film. Carbon fluoride generated by the reaction with fluorine ions is a reactive species that suppresses etching of the underlying silicon film and selectively etches the oxide film. Therefore, by using silicon carbide as a member constituting the vacuum vessel and applying high-frequency power to the silicon carbide, a decrease in the etching rate of the oxide film can be suppressed, and a high selectivity with respect to the base silicon can be obtained.

[0007]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a schematic sectional view of a microwave plasma etching apparatus. The microwave plasma etching apparatus will be described with reference to FIG. The microwave oscillated from the magnetron 1 propagates through the waveguide 2 and is guided into the vacuum vessel 4 via the discharge tube 3 made of quartz. The etching gas 6 supplied from the etching gas supply device (not shown) is turned into plasma by the magnetic field generated by the magnetic field generating solenoid coil 5 and the microwave electric field. The substrate 8 mounted on the mounting electrode 7 is etched by the plasma. The pressure at the time of etching is controlled by a vacuum exhaust device (omitted in the figure). The energy of the ions incident on the substrate 8 is controlled by the high-frequency power supplied to the mounting electrode 7 from the high-frequency power supply 9. Further, silicon (silicon) or carbon as a constituent component is sputtered on the electrode cover 10 made of silicon carbide provided on the mounting electrode 7 by the high frequency power. In addition, carbon fluoride is generated by a reaction with fluorine ions present in the plasma.

Table 1 shows the etching rate of the oxide film and the selectivity of the underlying silicon when CHF ₃ is used as an etching gas and alumina and silicon carbide are used for the electrode cover 10.

[0010]

[Table 1]

Microwave power 1 kW Pressure 1.3 Pa High frequency power 150 W

[0012]

According to the present invention, a decrease in the etching rate of the oxide film can be suppressed, and a high selectivity with respect to the underlying silicon film can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a microwave plasma etching apparatus according to the present invention.

[Explanation of symbols]

3: discharge tube, 5: solenoid coil, 7: mounting electrode, 8
... board, 9 ... high frequency power supply, 10 ... electrode cover.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshie Sato Kasamatsu, Yamaguchi Prefecture 794, Higashi-Toyoi, Hitachi Kasado Plant

Claims (1)

[Claims] In a microwave plasma etching apparatus for etching an oxide film with plasma generated by a magnetic field and a microwave electric field, silicon carbide is used as a constituent material of a vacuum vessel for generating plasma, and high-frequency power is supplied to the silicon carbide. A microwave plasma etching apparatus characterized by applying a voltage.