Plasma processing method

• US 5,374,327 A
• Filed: 04/28/1993
• Issued: 12/20/1994
• Est. Priority Date: 04/28/1992
• Status: Expired due to Term

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Koshimizu, Chishio, Ishii, Nobuo, Imahashi, Issei
• Primary Examiner(s): DANG, THI D
• Application Number:
  US08/053,353
• Time in Patent Office: 601 Days
• Field of Search: 156/626, 156/627, 156/643, 204/192.33, 204/192.13, 204/298.03, 204/298.32, 427/8-10, 427/571, 427/575
• US Class Current: 438/9
• CPC Class Codes: G01N 21/68 using high frequency electric fields

Abstract

HBr and Cl₂ are used as etching gases and Ar is used as a carrier gas in an ECR etching apparatus in which a semiconductor wafer is processed. Light emitted from plasma generated is dispersed by first and second spectroscopes to detect intensities of those spectra of the plasma which have first and second wavelengths. Both of these spectra are selected from those of an Ar atom. A CPU compares a present value, which represents a ratio of the spectral intensities detected, with a selected value of the ratio previously stored, and adjusts the intensity of a magnetic field such that the present value becomes closer to the selected value. The adjustment of the magnetic field intensity is carried out by changing the value of a current applied to magnetic coils. The magnetic field intensity is a parameter for adjusting an electron temperature of the plasma, and thus, the electron temperature of the plasma is adjusted by adjusting the magnetic field intensity.

Claims

1. A method of generating plasma for processing a substrate therewith in a process chamber, comprising the steps of:

selecting a plasma to be generated in said process chamber and raw gas for generating said plasma selected;

selecting a first parameter upon which a generation of said plasma depends, an electron temperature of said plasma being alterable by changing said first parameter;

generating control data as a function of intensities of spectra of light emitted from said plasma having first and second wavelengths, and establishing, as a first datum, a relationship between said control data and said electron temperature of said plasma;

establishing, as a second datum, a relationship between said electron temperature of said plasma and said first parameter;

establishing, as a third datum, a relationship between said control data and said first parameter of said first datum, and storing said third datum in a memory of a control unit;

storing a selected value of said control data in said memory of said control unit;

loading said substrate into said process chamber;

establishing a vacuum atmospheric condition within said process chamber;

introducing said raw gas into said process chamber while exhausting said process chamber;

generating plasma by forming said raw gas into generated plasma;

guiding light emitted from said generated plasma into first and second spectroscopes;

detecting intensities of spectra of said light emitted from said generated plasma having said first and second wavelengths via said first and second spectroscopes;

calculating a present value of said control data from detected spectral intensities of light emitted from said generated plasma by means of said control unit;

adjusting said first parameter via said control unit while monitoring said present value of said control data such that said present value becomes closer to said selected value of said control data over time; and

processing said substrate with said generated plasma, wherein each of said spectra of said light emitted from said generated plasma having said first or second wavelengths represents a first atom or molecule which neither substantially nor chemically acts on said substrate when said substrate is being processed, wherein said control data represents a ratio of an intensity of light emitted from said generated plasma having said first wavelength to an intensity of light emitted from said generated plasma having said second wavelength, and wherein said generated plasma is excited by electron cyclotron resonance.

2. The method according to claim 1, wherein said electron cyclotron resonance is caused by a magnetic field generated within said process chamber and microwaves introduced into said process chamber.

3. The method according to claim 2, wherein said first parameter represents an intensity of said magnetic field.

4. The method according to claim 2, wherein said raw gas includes gas containing atoms which enhance a chemical etching action on said substrate.

5. The method according to claim 4, wherein said first atom or molecule is selected from a group consisting of argon, helium, and nitrogen.

6. The method according to claim 4, wherein said first atom or molecule is hydrogen.

7. The method according to claim 4, wherein said raw gas comprises said first atom or molecule and serves as a monitoring gas for monitoring spectra of light emitted from said generated plasma.

8. A method of generating plasma for processing a substrate therewith in a process chamber, comprising the steps of:

selecting a plasma to be generated in said process chamber and raw gas for generating said plasma selected;

selecting a first parameter upon which a generation of said plasma depends, an electron temperature of said selected plasma being alterable by changing said first parameter;

generating control data as a function of intensities of spectra of light emitted from said plasma having first and second wavelengths, and establishing, as a first datum, a relationship between said control data and said electron temperature of said plasma;

establishing, as a second datum, a relationship between said electron temperature of said plasma and said first parameter;

establishing, as a third datum, a relationship between said control data and said first parameter of said first datum, and storing said third datum in a memory of a control unit;

storing a selected value of said control data in said memory of said control unit;

loading said substrate into said process chamber;

establishing a vacuum atmospheric condition within said process chamber;

introducing said raw gas into said process chamber while exhausted said process chamber;

generating plasma by forming said raw gas into generated plasma;

guiding light emitted from said generated plasma into first and second spectroscopes;

detecting intensities of spectra of said light emitted from said generated plasma having said first and second wavelengths via said first and second spectroscopes;

calculating a present value of said control data from detected spectral intensities of light emitted from said generated plasma by means of said control unit;

adjusting said first parameter via said control unit while monitoring said present value of said control data such that said present value becomes closer to said selected value of said control data over time; and

processing said substrate with said generated plasma, wherein each of said spectra of said light emitted from said generated plasma having first said first or second wavelengths represents a first atom or molecule which neither substantially nor chemically acts on said substrate when said substrate is being processed, wherein said control data represents a ratio of an intensity of light emitted from said generated plasma having said first wavelength to an intensity of light emitted from said generated plasma having said second wavelength, and wherein said plasma is excited by a high-frequency electric field generated between parallel plate electrodes within said process chamber.

9. The method according to claim 8, wherein said first parameter represents a pressure within said process chamber.

10. The method according to claim 8, wherein said raw gas includes gas containing atoms which enhance a chemical etching action on said substrate.

11. The method according to claim 10, wherein said first atom or molecule is selected from a group consisting of argon, helium, and nitrogen.

12. The method according to claim 10, wherein said first atom or molecule is hydrogen.

13. The method according to claim 10, wherein said raw gas comprises said first atom or molecule and serves as a monitoring gas for monitoring spectra of light emitted from said generated plasma.

14. A method of generating plasma for processing a substrate therewith in a process chamber, comprising the steps of:

selecting a plasma to be generated in said process chamber and raw gas for generating said plasma selected;

selecting a first parameter upon which a generation of said plasma depends, an electron density of said plasma being alterable by changing said first parameter;

generating control data as a function of intensities of spectra of light emitted from said plasma having first and second wavelengths, and establishing, as a first datum, a relationship between said control data and said electron density of said plasma;

establishing, as a second datum, a relationship between said control data and said electron density of said plasma;

establishing, as a third datum, a relationship between said control data and said first parameter of said first datum, and storing said third datum in a memory of a control unit;

storing a selected value of said control data in a memory of said control unit;

loading said substrate into said process chamber;

establishing a vacuum atmospheric condition within said process chamber;

introducing said raw gas into said process chamber while exhausting said process chamber;

generating plasma by forming said raw gas into generated plasma;

guiding light emitted from said generated plasma into first and second spectroscopes;

detecting intensities of spectra of said light emitted from said generated plasma having said first and second wavelengths via said first and second spectroscopes;

calculating a present value of said control data from detected spectral intensities of light emitted from said generated plasma by means of said control unit;

adjusting said first parameter via said control unit by monitoring said present value of said control data such that said present value becomes closer to said selected value of control data over time; and

processing said substrate with said generated plasma, wherein each of said spectra of said light emitted from said generated plasma having said first or second wavelengths represents a first atom or molecule which neither substantially nor chemically acts on said substrate when said substrate is being processed, wherein said control data represents a ratio of an intensity of light emitted from said generated plasma having said first wavelength to an intensity of light emitted from said generated plasma having said second wavelength, and wherein said generated plasma is excited by electron cyclotron resonance.

15. The method according to claim 14, wherein said electron cyclotron resonance is caused by a magnetic field generated within said process chamber and microwaves introduced into said process chamber.

16. The method according to claim 15, wherein said first parameter represents an intensity of said microwaves.

17. The method according to claim 15, wherein said raw gas includes gas containing atoms which enhance a chemical etching action on said substrate.

18. The method according to claim 17, wherein said first atom or molecule is selected from a group consisting of argon, helium, and nitrogen.