Patent ID: 8003543

Claim:
A method of forming a pattern of a semiconductor device, comprising: providing a substrate having an electrically insulating film disposed thereon; forming a first film and a first hard mask layer on the insulating film; forming a first sacrificial pattern of substantially identical features on the first hard mask layer, wherein the features are spaced from one another in a first direction by a first pitch; forming a second hard mask layer on the first sacrificial pattern and the first hard mask layer, wherein the second hard mask layer delimits recesses each of which extends between a respective pair of adjacent ones of the features of the first sacrificial pattern; forming a second sacrificial pattern within the recesses; removing upper portions of the second hard mask layer to expose the first sacrificial pattern; subsequently removing the first sacrificial pattern and the second sacrificial pattern to form a plurality of projections, constituted by the second hard mask layer, on the first hard mask layer; subsequently forming a mask having an opening on the substrate, wherein the opening exposes portions of the first hard mask layer and the second hard mask layer; etching the second hard mask layer and the first hard mask layer using the mask having the opening as an etch mask to form a hard mask of residual portions of the first hard mask layer and the second hard mask layer; etching the first film using the mask having the opening and the hard mask together as an etch mask to form a first pattern; and etching the insulating film using the mask having the opening and the first pattern together as an etch mask to form contact holes in the insulating film.