Method for detecting etching endpoint, and etching apparatus and etching system using the method thereof

• US 6,669,810 B1
• Filed: 10/14/1998
• Issued: 12/30/2003
• Est. Priority Date: 12/08/1994
• Status: Expired due to Term

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Sumitomo Metal Industries Limited (Nippon Steel Corporation)
• Inventors: Hayami, Toshihiro, Miyazaki, Toshiya, Nakatsuka, Tadao, Nakamura, Toshiyuki, Tanaka, Hiroyuki
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): ALEJANDRO MULERO, LUZ L
• Application Number:
  US09/172,289
• Time in Patent Office: 1,903 Days
• Field of Search: 156/345.25, 118/712, 204/298.32
• US Class Current: 156/345.1
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32963 End-point detection
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

A method for detecting an etching endpoint and a plasma etching apparatus and a plasma etching system using such a device are disclosed, in which time series data of a signal corresponding to the amount of light of the plasma light generated during the plasma etching process are arithmetically processed, so that the change of light amount is corrected and an etching endpoint is detected from the time series data after the correction.

Claims

1. A system for detecting an etching endpoint on the basis of plasma light generated during the plasma etching process, comprising:

means for receiving the plasma light into a photoelectrically transduced signal and photoelectrically transducing said plasma light;

means for producing a time series data including a plurality of data values of the photoelectrically transduced signal;

correcting means for digitally correcting the change of light amount due to change in the quality of the received plasma light of an arithmetic operation performed on said time series data; and

means for detecting an etching endpoint from the corrected time series data.

2. An etching endpoint detecting system according to claim 1, further comprising:

means for calculating an average value of an initial time series data for a predetermined period of time; and

means for calculating a coefficient for corrective arithmetic operation using said average value,

wherein said correction means corrects the time series data using said coefficient.

3. An etching endpoint detecting system according to claim 2, wherein said correction means offsets the initial value of the time series data to zero and multiplies the offset time series data by a predetermined value in addition to correcting the change of light amount.

4. An etching endpoint detecting system according to claim 2, wherein said correcting means sets a reference value for a predetermined period when the amount of light becomes stable during the etching process and corrects the time series data after the predetermined period using said reference value.

5. An etching endpoint detecting system according to claim 1, wherein said correction means corrects the time series data by a function holding the ratio between values apart from each other by a predetermined period of time.