Computer program product and method of controlling polishing of a substrate

摘要

A method of controlling polishing includes polishing a substrate of a non-metallic layer undergoing polishing and a metal layer underlying the non-metallic layer; storing a metal reference spectrum, the metal reference spectrum being a spectrum of light reflected from a same metal material as the metal layer; measuring a sequence of raw spectra of light reflected from the substrate during polishing with an in-situ optical monitoring system; normalizing each raw spectrum in the sequence of spectra to generate a sequence of normalized spectra, of which normalizing includes a division operation where the measured spectrum is in the numerator and the metal reference spectrum is in the denominator; and determining at least one of a polishing endpoint or an adjustment for a polishing rate based on at least one normalized predetermined spectrum from the sequence of normalized spectra.

主权项

1. A computer program product for controlling polishing, the computer program product tangibly embodied in a non-transitory computer readable medium and comprising instructions to cause a processor to:
receive from an in-situ optical monitoring system, during polishing of a substrate that includes a non-metallic first layer undergoing polishing, a semiconductor second layer, and a third layer between the non-metallic first layer and the semiconductor second layer, a sequence of raw spectra of light reflected from the substrate; store a reference spectrum, the reference spectrum being a spectrum of light reflected from a same material as the third layer; normalize each raw spectrum in the sequence of raw spectra to generate a sequence of normalized spectra, wherein the instructions to normalize include a division operation in which the raw spectrum is in the numerator and the reference spectrum is in the denominator; and determine at least one of a polishing endpoint or an adjustment for a polishing rate based on at least one normalized predetermined spectrum from the sequence of normalized spectra.