Patent ID: 6544887
Filing Date: 2003-04-08
Classification: H01L

Abstract:
A method for forming a plurality of contact openings, comprising:providing a polycide layer disposed over a substrate, said polycide layer including a polysilicon layer disposed above said substrate and a metal silicide layer disposed above said polysilicon layer; forming a patterned mask layer over a first portion and a second portion of said polycide layer to expose said metal silicide layer, the first portion defined over a thinner polycide layer than the second portion; selectively etching with a silicide etch said silicide layer to define a first and second contact opening therein, said silicide etch being effective to substantially remove said exposed portions of said silicide layer; performing a polycide etch to extend said contact openings towards said substrate and continuing until said substrate has been exposed at said first contact opening, said polycide etch having a polycide selectivity greater than one such that said metal silicide layer is etched at a faster rate than said polysilicon layer; and performing a poly overetch such that the second contact opening exposes said substrate.