Patent ID: 6074954
Filing Date: 2000-06-13
Classification: H01L

Abstract:
A method for recess etchback of a polysilicon-filled trench formed in a substrate, wherein the method comprises the steps of:a) providing a trench formed in a semiconductor structure, wherein said structure includes a substrate, at least one gate dielectric layer overlying a surface of said substrate, and at least one etch barrier layer overlying said gate dielectric layer;b) forming a conformal dielectric film overlying said etch barrier layer and the sidewall and bottom of said trench;c) filling said trench with a layer of polysilicon which overlies said conformal dielectric film; andd) isotropically etching said polysilicon back to a depth within said trench using a plasma produced from a plasma source gas comprising a reactive species which selectively etches polysilicon, wherein said plasma source gas comprises from about 80% to about 95% by volume of a fluorine-comprising gas, and from about 5% to about 20% by volume of an additive gas selected from the group consisting of a bromine-comprising gas, a chlorine-comprising gas, an iodine-comprising gas, or a combination thereof.