Patent ID: 8012846

Claim:
A method of forming a shallow trench isolation structure, comprising the steps of: (a) forming an opening within a substrate and through a pad oxide formed thereover; (b) forming a first substantially conformal liner layer along walls of the opening; (c) performing a first annealing step to increase a density of the first liner layer, before depositing a second substantially conformal liner layer; (d) after step (c), forming the second substantially conformal liner layer comprising a tetraethoxysilane (TEOS) layer along the walls of the opening and over the annealed first liner layer without filling the opening, wherein the step of forming the second liner layer comprises a first sub-atmospheric pressure chemical vapor deposition (SACVD) process without using a processing bias; (e) performing a second annealing step so as to increase a density of the second liner layer, before filling the opening; and (f) forming a dielectric layer over the TEOS layer, the dielectric layer substantially filling the opening.