The influence of wafer edge profile on STI-CMP process

Abstract

Optimum wafer edge profile for uniform removal rate near wafer edge in STI-CMP process was investigated. The distribution of removal rate was estimated by calculating the contact pressure on wafer surface using FEM analysis. As a result, shortening the edge width is confirmed to achieve flatter distribution of removal rate near the wafer edge. To meet the specification for the generation of hp=36nm with 1.5mm edge exclusion, the edge width would be reduced to 250um in case of ROA being 100nm.