Patent ID: 7205240

Claim:
A method for depositing a film to fill a gap in a surface of a substrate, the method comprising: depositing a first portion of the film in the gap using a first gaseous mixture in a high-density-plasma chemical-vapor-deposition (HDP-CVD) process, the first gaseous mixture consisting of a first process gas and a first fluent gas, the first process gas having chemical elements incorporated into the film and the first fluent gas not having chemical elements incorporated into the film, wherein the first process gas comprises a silicon-containing gas and an oxygen-containing gas; thereafter, etching the film with a fluorine-containing gas; and thereafter, depositing a remainder of the film in the gap using a remainder gaseous mixture in an HDP-CVD process, the remainder gaseous mixture consisting of a second process gas and a second fluent gas, the second process gas having chemical elements incorporated into the film and the second fluent gas not having chemical elements incorporated into the film, wherein the second process gas comprises a silicon-containing gas and an oxygen-containing gas, wherein the second fluent gas has a lower average molecular weight than the first fluent gas.