Method of determining etch endpoint using principal components analysis of optical emission spectra
AssigneeAdvanced Micro Devices, Inc.
InventorsAnthony John Toprac, Hongyu Yue
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Abstract
A method is provided for determining an etch endpoint. The method includes collecting intensity data representative of optical emission spectral wavelengths during a plasma etch process. The method further includes calculating Scores from at least a portion of the collected intensity data using at most first, second, third and fourth Principal Components derived from a model. The method also includes determining the etch endpoint using Scores corresponding to at least one of the first, second, third and fourth Principal Components as an indicator for the etch endpoint.
Claims20
A method for determining an etch endpoint, the method comprising:
- collecting intensity data representative of optical emission at a plurality of spectral wavelengths during a plasma etch process;
- determining a plurality of Loadings using at least a portion of previous intensity data representative of optical emission at the plurality of spectral wavelengths, the previous intensity data being collected during a plurality of previous plasma etch processes;
- calculating a plurality of approximate Scores from at least a portion of the collected intensity data using the plurality of Loadings;
- and
- determining the etch endpoint using the approximate Scores.
A method for etching a wafer, the method comprising:
- etching a wafer using a plasma process so that a light-emitting discharge is produced;
- terminating the etching of the wafer when an etch endpoint is determined, wherein the determination of the etch endpoint further comprises:
- collecting intensity data representative of optical emission at a plurality of spectral wavelengths during a plasma etch process;
- determining a plurality of Loadings using at least a portion of previous intensity data representative of optical emission at the plurality of spectral wavelengths, the previous intensity data being collected during a plurality of previous plasma etch processes;
- calculating a plurality of approximate Scores from at least a portion of the collected intensity data using the plurality of Loadings;
- and
- determining the etch endpoint using the approximate Scores.
Dependencies are inferred from the claim text.