Patent ID: 6672941
Filing Date: 2004-01-06
Classification: B24B,H01L

Abstract:
A chemical/mechanical planarization apparatus to planarize a surface of a substrate while forming shallow trench isolation to reduce dishing of wide trench shallow trench isolation and to reduce erosion of small silicon nitride areas on the surface of the substrate, comprising:a first chemical/mechanical planarization platen having a first product of a pressure applied between the substrate and said platen and the relative velocity between the substrate and the platen to chemical/mechanical planarization polish said substrate at a high rate with low selectivity; an end point determining means to detect while said substrate is being chemical/mechanical planarization polished on the first platen to determine if the surface of the substrate has reached an end point exposure of the silicon nitride areas by measuring techniques selected from a group of measuring techniques consisting of measuring an increase in current of a motor driving a wafer carrier holding said substrate and ellipsometrically measuring said trench oxide overlaying said silicon nitride area; and a second chemical/mechanical planarization polishing platen having a second product of the pressure applied between the substrate and the platen and the relative velocity between the substrate and the platen to chemical/mechanical planarization polish, after the end point exposure of the silicon nitride areas is reached, to slowly over polish the surface of the substrate to control the thickness of a trench oxide of the shallow trench isolation to reduce dishing and reduce erosion of the silicon nitride areas.