Patent ID: 7648921

Claim:
A method of forming a dielectric layer, comprising: providing a substrate, on which a plurality of protruding structures is formed, and a space is between two of the adjacent protruding structures; forming a liner layer on the substrate and the plurality of protruding structures; forming a first dielectric layer on the substrate, wherein the first dielectric layer located in the spaces comprises two adjacent overhangs and voids are formed under the overhangs below a top surface of each of the plurality of the protruding structures; and performing an etch-back process to remove a part of the first dielectric layer and a part of the liner layer to at least cutting off the overhangs, and exposing the voids and widening the voids, so as to form a plurality of openings forming a second dielectric layer on the substrate by performing an HDP-CVD process to cover the first dielectric layer and fill up the openings.