Plasma processing apparatus and processing method

• US 5,759,424 A
• Filed: 03/22/1995
• Issued: 06/02/1998
• Est. Priority Date: 03/24/1994
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kamimura, Takashi, Imatake, Mitsuko, Sasaki, Ichiro, Tamura, Hitoshi, Otsubo, Toru
• Primary Examiner(s): DANG, THI D
• Application Number:
  US08/409,077
• Time in Patent Office: 1,168 Days
• Field of Search: 156/345, 156/626.1, 156/627.1, 216/60, 216/59, 204/192.13, 204/192.33, 204/298.03, 204/298.32
• US Class Current: 216/60
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/3299 Feedback systems

Abstract

A plasma processing apparatus is provided with a processing chamber having at least a pair of opposing windows to allow observation of the interior thereof, a plasma generation unit for generating a plasma in the processing chamber, a plasma light emission monitoring unit arranged externally of the processing chamber for monitoring the light emission of the plasma through one of the pair of opposing windows, a reference light irradiation unit for irradiating a reference light to the plasma light emission monitoring unit from that window of the pair of opposing windows which is opposite to the plasma light emission monitoring unit through the pair of opposing windows, and a control for controlling a plasma processing state of the substrate to be processed by comparing the data on the light emission of the plasma monitored by the plasma light emission unit and the reference light.

Claims

1. A plasma processing method for a plasma processing apparatus, comprising the steps of:

detecting a light emission of a plasma generated in a plasma processing chamber and a light of a known spectrum emitted from a light source external of said plasma processing chamber and transmitted through said plasma processing chamber;

determining a difference between a spectrum of the light emission of the plasma and a spectrum of the light of the known spectrum after being transmitted through said plasma processing chamber;

determining an internal state of said plasma processing chamber based on the difference of the spectra; and

controlling a setting condition of said processing apparatus to control a plasma characteristic within said plasma processing chamber based on said internal state.

2. A plasma processing method as claimed in claim 1, wherein said controlling step more specifically controls a plasma characteristic within said plasma processing chamber to be substantially constant based on said internal state from said determining step.

3. A plasma processing method as claimed in claim 1, wherein said controlling step more specifically controls at least one of a processing pressure, a gas flow rate and a plasma generation power to control said plasma characteristic.

4. A plasma processing method for a plasma processing apparatus, comprising the steps of:

detecting the plasma light emission of a plasma generated in a plasma processing chamber through a window and a light of a known spectrum emitted from a light source external of a plasma processing apparatus and transmitted through a same said window of the plasma processing apparatus;

determining a difference between a spectrum of the plasma light emission and a spectrum of the light of the blown spectrum and determining an internal state of the plasma processing chamber based on the difference of the spectrum; and

controlling a setting condition of said processing apparatus to control a plasma characteristic within said plasma processing chamber based on said internal state.

5. A plasma processing method according to claim 4, further comprising the step of controlling a condition of the plasma to maintain a spectrum of the detected light emission of the plasma substantially constant.

6. A plasma processing apparatus for plasma processing a wafer comprising:

a light source of a known spectrum;

a sampling window for sampling a plasma light emission;

an optical system for directing a light through said sampling window and a processing chamber;

an optical system for directing a light not through said processing chamber;

a spectrometer for analyzing a spectrum; and

a controller;

wherein an internal state of said sampling window is detected based on a difference between spectra of the lights emitted from said light source derived by said spectrometer through said optical systems, and an internal state of said processing chamber is detected based on the detected internal state of said sampling window; and

said controller controlling a setting condition of said processing apparatus to control a plasma characteristic within said processing chamber based on said internal state.

7. A plasma processing apparatus for processing a wafer by plasma comprising:

a processing chamber having a sampling window for sampling a plasma light emission; and

a reference light source external to said processing chamber for shining a reference light through said processing chamber and said sampling window;

means for comparing the plasma light emission and reference light sampled through said sampling window to detect an internal state of said processing chamber; and

a controller controlling a setting condition of said processing apparatus to control a plasma characteristic within said processing chamber based on said internal state.

9. A plasma processing apparatus according to claim 7 wherein an effective value of a setting condition of processing is estimated based on a result of monitoring of said internal state.

8. A plasma processing apparatus for processing a wafer by plasma comprising:

a processing chamber having a sampling window for sampling a plasma light emission; and

a reference light source external to said processing chamber for shining a reference light through said processing chamber and said sampling window;

means for comparing the plasma light emission and reference light sampled through said sampling window to detect an internal state of said processing chamber; and

means for controlling a processing condition of said processing apparatus based upon said internal state to maintain a spectrum of the plasma through said sampling window substantially constant.

10. A plasma etching method for a plasma etching apparatus, comprising the steps of:

detecting a light emission of a plasma generated in a plasma etching chamber and a light of a known spectrum emitted from a light source external of said plasma etching chamber and transmitted through said plasma etching chamber;

determining a difference between a spectrum of the light emission of the plasma and a spectrum of the light of the known spectrum after being transmitted through said plasma etching chamber;

determining an internal state of said plasma etching chamber based on the difference of the spectra; and

controlling a setting condition of said processing apparatus to control a plasma characteristic within said plasma etching chamber based on said internal state.

11. A plasma etching apparatus for processing a wafer by plasma comprising:

a processing chamber having a sampling window for sampling a plasma light emission; and

a reference light source external to said processing chamber for shining a reference light through said processing chamber and said sampling window;

means for comparing the plasma light emission and reference light sampled through said sampling window to detect an internal state of said processing chamber; and

a controller controlling a setting condition of said processing apparatus to control a plasma etching characteristic within said processing chamber based on said internal state.

12. A plasma etching apparatus as claimed in claim 11, wherein said controller more specifically controls said plasma etching characteristic within said processing chamber to be substantially constant based of said internal state detected by said means for comparing.

13. A plasma etching apparatus as claimed in claim 11, wherein said controller more specifically controls at least one of a processing pressure, a gas flow rate and a plasma generation power to control said plasma etching characteristic.

14. A plasma processing apparatus comprising:

a processing chamber having a substrate to be processed arranged therein and maintaining processing gas at a predetermined pressure and having at least a pair of opposing windows to allow observation of the interior thereof;

plasma generation means for generating a plasma in said processing chamber having the processing gas maintained at the predetermined pressure;

plasma light emission monitor means arranged externally of said processing chamber for monitoring the light emission of the plasma through one of said pair of opposing windows;

reference light irradiation means for irradiating a reference light to said plasma light emission monitoring means from that window of said pair of opposing windows which is opposite to said plasma light emission monitoring means and through said processing chamber using said pair of opposing windows; and

control means for controlling a setting condition of said plasma processing apparatus to control a plasma characteristic within said processing chamber based on a comparison of the data on the light emission of the plasma and the reference light as monitored by said plasma light emission means.