Wafer Polishing Endpoint Detection Methods and Systems

Abstract

This invention discloses a method for detecting the endpoint of wafer polishing, comprising the following steps: S1, establishing a theoretical reflectivity spectrum reference library and establishing a correspondence between reflectivity spectra and the thickness of the wafer layer to be polished; S2, grouping the theoretical reflectivity spectrum reference library and determining the representative spectrum for each group; S3, collecting spectral information of wafer reflection using a detector, processing it to obtain a measured reflectivity spectrum; S4, comparing the measured reflectivity spectrum with the theoretical reflectivity spectrum reference library step by step to determine the corresponding thickness; S5, determining the wafer polishing endpoint based on the thickness of the measured reflectivity spectrum. This invention also discloses a wafer polishing endpoint detection system. This invention establishes the relationship between reflectivity spectrum and the thickness of the wafer layer to be polished, determines the thickness of the layer to be polished to judge the wafer polishing endpoint, avoids using characteristic values ​​or intermediate variables, and therefore has flexibility; it can generate reference reflectivity spectra with different thickness spacings, improving the accuracy near the expected thickness of the polishing endpoint.

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