Plasma processor

• US 5,115,167 A
• Filed: 04/04/1989
• Issued: 05/19/1992
• Est. Priority Date: 04/05/1988
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Tsuda, Mutsumi, Ootera, Hiroki
• Primary Examiner(s): Laroche, Eugene R.
• Assistant Examiner(s): YOO, DO H
• Application Number:
  US07/333,042
• Time in Patent Office: 1,141 Days
• Field of Search: 315/111.21, 315/111.41, 315/111.81, 313/231.31, 250/423 R, 204/298.38, 204/298.01, 204/192.1
• US Class Current: 315/111.21
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32275 Microwave reflectors
• CPC Class Codes: H01J 37/32293 using particular waveforms, e.g. polarised waves

Abstract

A plasma processor comprising a plasma generation portion in which a plasma is generated by electron cyclotron resonance, a source of a right hand polarized microwave and supplying it to the plasma generation portion, and a plasma reaction portion which accommodates a substrate to be processed with the plasma generated in the plasma generation portion. Owing to the production and supply of the right hand polarized microwaves, almost all of the microwaves injected into the plasma generation portion contribute to the generation of the plasma, to increase plasma density and raise processing speed.

Claims

1. A plasma processor comprising a chamber including a cylindrical plasma generation portion in which an electron cyclotron resonance plasma is generated, means for producing a magnetic field in said plasma generation portion for establishing the electron cyclotron resonance plasma, means for supplying a gas to the plasma generation portion in which the electron cyclotron resonance plasma is established, and means for producing right hand polarized microwave energy and for supplying the right hand polarized microwave energy and for supplying the right hand polarized microwave energy to said plasma generation portion including a magnetron oscillator and a circular cross-section waveguide interposed between said magnetron oscillator and said plasma generation portion for transmitting right hand polarized microwave energy, said chamber including a plasma reaction portion for retaining a substrate to be processed with the plasma generated in said plasma generation portion, wherein said cylindrical plasma generation portion and said circular waveguide each have diameters, and the diameter of said plasma generation portion is larger than the diameter of said circular waveguide.

2. A plasma processor comprising a chamber including a plasma generation portion in which an electron cyclotron resonance plasma is generated, means for producing a magnetic field in said plasma generation portion for establishing the electron cyclotron resonance plasma, means for supplying a gas to the plasma generation portion in which the electron cyclotron resonance plasma is established, and means for producing right hand polarized microwave energy and for supplying the right hand polarized microwave energy to said plasma generation portion, said chamber including a plasma reaction portion for retaining a substrate to be processed with the plasma generated in said plasma generation portion, wherein the means for producing and supplying the right hand polarized microwave energy includes a magnetron oscillator for producing linearly polarized microwave energy, a rectangular waveguide for propagating the linearly polarized microwave energy produced by said magnetron oscillator in a rectangular mode toward said plasma generation portion, a rectangular-circular mode converter disposed between said rectangular waveguide and said plasma generation portion for converting the linearly polarized rectangular mode microwave energy into linearly polarized circular mode microwave energy, and a wave generator for converting the linearly polarized circular mode microwave energy into right hand polarized circular mode microwave energy and for supplying the right hand polarized circular mode microwave energy to said plasma generation portion.

3. A plasma process comprising a chamber including a plasma generation portion in which an electron cyclotron resonance plasma is generated, means for producing a magnetic field in said plasma generation portion for establishing the electron cyclotron resonance plasma, means for supplying a gas to the plasma generation portion in which the electron cyclotron resonance plasma is established, and means for producing microwave energy to said plasma generation portion, said chamber including a plasma reaction portion for retaining a substrate to be processed with the plasma generated in said plasma generation portion, said plasma generation portion including an inlet part for receiving microwave energy and a vacuum vessel part, said inlet part including expansion means for expanding microwave energy received form said means for producing microwave energy, means for transmitting the microwave energy from said expansion means to said vacuum vessel part, and means for making substantially uniform the microwave energy density distribution along a radial direction in said vacuum vessel part wherein said expansion means comprises an expanding part of said chamber disposed between said means for producing microwave energy and said vacuum vessel part and said means for making substantially uniform comprises a dielectric lens disposed in said inlet part.

4. A plasma processor comprising a chamber including a plasma generation portion in which an electron cyclotron resonance plasma is generated, means for producing a magnetic field in said plasma generation portion for establishing the electron cyclotron resonance plasma, means for supplying a gas to the plasma generation portion in which the electron cyclotron resonance plasma is established, and means for producing microwave energy and for supplying the microwave energy to said plasma generation portion, said chamber including a plasma reaction portion for retaining a substrate to be processed with the plasma generated in said plasma generation portion, said plasma generation portion including an inlet part for receiving microwave energy and a vacuum vessel part, said inlet part including expansion means for expanding microwave energy received from said means for producing microwave energy, means for transmitting the microwave energy from said expansion means to said vacuum vessel part, and means for making substantially uniform the microwave energy density distribution along a radial direction in said vacuum vessel part wherein said expansion means and said means for making substantially uniform are disposed in said inlet part and include a sub reflector for reflecting microwave energy from said means for producing microwave energy and a main reflector disposed in said inlet part for reflecting microwave energy that has been reflected by said subreflector into said vacuum vessel part.

5. A plasma processor according to claim 4 wherein said sub reflector is disposed in said inlet part for entirely reflecting incident microwave energy.