Patent ID: 8652862

Claim:
A method for etching an insulating film comprising the steps of: forming an insulating film; forming a first resin layer composed of a non-silicon-containing resin on the insulating film; forming a pattern including projections and recesses in the first resin layer; forming a second resin layer composed of a silicon-containing resin to cover the projections and the recesses of the pattern in the first resin layer; etching the second resin layer by reactive ion etching with etching gas containing CF 4 gas and oxygen gas until the projections of the first resin layer are exposed, a Si component of the second resin layer being oxidized in etching the second resin layer; selectively etching the first resin layer until the insulating film is exposed using as a mask the second resin layer buried in the recesses of the first resin layer to form a resin layer mask; and etching the insulating film using the resin layer mask, wherein in the step of etching the second resin layer, the reactive ion etching is performed under applying a self-bias voltage so that a Si product is removed, the Si product being provided from the Si component remaining in the second resin layer without being oxidized.