Patent ID: 6194285
Filing Date: 2001-02-27
Classification: H01L

Abstract:
A method of forming a shallow trench isolation comprising the steps of:providing a substrate having predetermined active areas and passive regions;forming a pad oxide layer over said substrate;forming a nitride layer over said pad oxide layer;forming organic BARC layer over said nitride layer;forming a first photoresist layer over said organic BARC layer;patterning said first photoresist layer to form a first photoresist mask defining openings for at least one shallow trench to be formed in said substrate;etching said organic BARC layer, said nitride layer and said pad oxide layer through said openings in said first photoresist mask to expose a portion of said substrate;etching said exposed portion of said substrate to form a shallow trench in said substrate;removing said first photoresist mask;forming a conformal layer of oxide on the inside walls of said shallow trench;filling said shallow trench with isolation oxide;forming a second photoresist layer over said substrate;patterning said second photoresist layer to form a second photoresist mask defining reverse openings corresponding to at least one active area in said substrate;etching said isolation oxide through said reverse openings in said second photoresist mask until said organic BARC layer over said active area is reached;removing said second photoresist mask over said substrate;performing chemical mechanical polishing of said isolation oxide until stopping on said organic BARC layer on said substrate;removing said organic BARC layer and said nitride layer;performing well implanting over said substrate using pad oxide as a screen oxide;growing low temperature oxide to anneal the surface of said substrate;removing said pad oxide and said low temperature oxide; andgrowing gate oxide layer over said substrate.