CMP PROCESS CONTROL VIA IN-SITU AND REAL-TIME CHEMICAL ENDPOINT DETECTION

摘要

A proven technology has been developed for monitoring and controlling the CMP processes involving a stop at a layer which contains nitride. This technology is based on the fact that a measurable amount of ammonia (NH_3) will be generated during the nitride polishing. The detection of ammonia is accomplished by converting ammonia to nitrogen monoxide (NO) catalytically, then reacting the NO with ozone (O_3) to form excited state nitrogen dioxide (NO_2~*) followed by detecting its light emission. The endpoint detection system is designed to analyze and to measure these very small changes of ammonia concentration within the slurry with high velocity (～ 1 sec) and accuracy (ppb). The system is already approved for BPSG and STI CMP processes on different polisher types - Ebara and SpeedFam-IPEC (Westech and Auriga C).