Determining endpoint in etching processes using real-time principal components analysis of optical emission spectra

摘要

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 analyzing at least a portion of the collected intensity data into at most first and second Principal Components with respective Loadings and corresponding Scores. The method also includes determining the etch endpoint using the respective Loadings and corresponding Scores of the second Principal Component as an indicator for the etch endpoint using real-time Principal Components Analysis applied to optical emission spectral data from a previous portion of the plasma etch process.