Patent ID: 8034693

Claim:
A method for fabricating a semiconductor device including a multilayer wiring structure including a plurality of wiring layers having an air gap between wirings, the method comprising the steps of: forming an insulating film on a semiconductor substrate; forming a plurality of wiring trenches in the insulating film; forming a plurality of the wirings in the plurality of wiring trenches; forming a resist mask having an opening for selectively exposing one of regions between the plurality of wirings, on the insulating film and the plurality of wirings; forming an air gap trench by removing the insulating film from the selectively exposed one of the regions between the plurality of wirings by etching using the resist mask; and forming the air gap in the air gap trench by depositing an inter-layer insulating film over the plurality of wirings after removal of the resist mask, wherein the air gap is formed only in at least one wiring layer having a relatively thin film thickness of the plurality of wiring layers.