Method of forming isolated regions of oxide.

摘要

A method is provided for forming isolated regions of oxide of an integrated circuit, and an integrated circuit formed according to the same. A pad oxide layer (12) is formed over a portion of a substrate (10). A first silicon nitride layer (14) is formed over the pad oxide layer. A polysilicon buffer layer (16) is then formed over the first silicon nitride layer (14). A second silicon nitride layer (18) is formed over the polysilicon layer. A photoresist layer is formed and patterned over the second silicon nitride layer. An opening is etched through the second silicon nitride layer and the polysilicon buffer layer to expose a portion of the first silicon nitride layer (14). A third silicon nitride region (24) is then formed on at least the polysilicon buffer layer (16) exposed in the opening. The first silicon nitride layer (14) is etched in the opening. A field oxide region (26) is then formed in the opening. <IMAGE> <IMAGE>