Patent ID: 6149761
Filing Date: 2000-11-21
Classification: B24B,H01J,H01L

Abstract:
A plasma etching apparatus comprising: a vacuum processing chamber;electrodes arranged in said vacuum processing chamber, with an object being placed on one of said electrodes and a high frequency voltage being to be applied to said electrodes;means for introducing a process gas into said vacuum processing chamber;means for exhausting said vacuum processing chamber;a detection window formed a wall of said vacuum processing chamber; anda system for detecting an etching endpoint based on plasma light detected by way of the detection window, wherein said etching endpoint detection system includes:means for receiving the plasma light through said detection window and photoelectrically transducing said plasma light into a photoelectrically transduced signal;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 changes in the quality of the received plasma light for an arithmetic operation performed on said time series data; andmeans for detecting an etching endpoint from the corrected time series data.