Patent ID: 8755928
Filing Date: 2014-06-17
Classification: B24B,G01J

Abstract:
1. A computer-implemented method of generating reference spectra, comprising: polishing a plurality of set-up substrates, the plurality of set-up substrates comprising at least three set-up substrates; measuring a sequence of multi-wavelength spectra from each of the plurality of set-up substrates during polishing with an in-situ optical monitoring system to provide a plurality of sequences of spectra; for each set-up substrate from the plurality if set-up substrates, generating a sequence of potential reference spectra from the sequence of multi-wavelength spectra for the set-up substrate, thereby generating a plurality of sequences of potential reference spectra from the plurality of sequences of spectra; determining which sequence of potential reference spectra of the plurality of sequences of potential reference spectra provides a best match to remaining sequences of the plurality of sequences of potential reference spectra, wherein determining comprises a round-robin comparison of each sequence of potential reference spectra against each other sequence of potential reference spectra; and selecting and storing the sequence of potential reference spectra determined to provide the best match as reference spectra.