Method of producing reference spectral library for use in film-thickness estimation for workpiece

Abstract

[Problem] This invention provides a technique to expand the range of multiple reference spectra used for film thickness estimation on workpieces such as wafers, thereby increasing the range of film thicknesses that can be estimated. [Solution] The method for creating a reference spectrum library involves generating a pre-grinding reference spectrum corresponding to a pre-grinding time tm-1 before the start of grinding on the reference workpiece (tm) and a post-grinding reference spectrum corresponding to a post-grinding time tn+1 after the end of grinding on the reference workpiece (tn) by extrapolation. Multiple reference film thicknesses T-1 to T+1 corresponding to the pre-grinding reference spectrum, multiple actual reference spectra, and post-grinding reference spectra are calculated. A reference spectrum library is created by associating the multiple reference film thicknesses T-1 to T+1 with the pre-grinding reference spectrum, multiple actual reference spectra, and post-grinding reference spectrum, respectively.

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