Patent ID: 7723177

Claim:
A method comprising: forming a pad oxide layer and an insulating layer on a semiconductor substrate and then performing a first etching process on the semiconductor device to form an insulating layer pattern exposing a portion of the pad oxide layer in a trench area; and then performing a second etching process with respect to the pad oxide layer by using the insulating layer pattern as a mask; and then performing a blanket ion implantation process with respect to the insulating layer pattern and the exposed portion of the pad oxide layer to form an ion layer in the semiconductor substrate; and then performing a third etching process with respect to the semiconductor substrate to simultaneously form a pad oxide layer pattern and a trench in the semiconductor substrate, wherein performing the third etching processes comprises using ions from the ion layer as an etching gas; and then forming an insulating layer on the semiconductor substrate including the trench; and then performing a planarization process with respect to the semiconductor substrate including the insulating material and removing the pad oxide layer pattern and the insulating layer pattern, thereby forming an isolation layer in the trench.