ENDPOINT CONTROL DURING CHEMICAL MECHANICAL POLISHING BY DETECTING INTERFACE BETWEEN DIFFERENT LAYERS THROUGH SELECTIVITY CHANGE

摘要

Embodiments described herein relate to methods of detecting an endpoint for a target substrate during chemical mechanical polishing process. In one embodiment, the method includes polishing one or more target substrates at a first film removal rate to provide reference spectra, polishing one or more target substrates at a second film removal rate to provide current spectra of the one or more target substrates, wherein the second film removal rate is different from the first film removal rate, identifying an interface transition between different layers formed on the one or more target substrates using a sequence of endpoint values obtained based on the reference spectra collected during polishing of the one or more reference substrates.