Patent ID: 8003487

Claim:
A method of manufacturing a semiconductor device, comprising: forming first patterns separated from each other by a first width and second patterns separated from each other by a second width wider than the first width, on a substrate; etching the substrate using the first patterns and the second patterns as an etching mask to form a first trench having a first depth and a preliminary second trench having a second depth; forming a sacrificial layer to cover the first patterns and fill up a space between the first patterns while simultaneously filling up a space between the second patterns and exposing at least a floor of the preliminary second trench; and etching the substrate using the sacrificial layer as an etching mask to form a second trench having a third depth deeper than the second depth, wherein the sacrificial layer is formed by a polymer attachment process using a gas for forming the polymer; and wherein the polymer attachment process is performed at a temperature of about 500° C. to about 800° C.