Patent ID: 9607850
Date: 2017-03-28
CPC Classifications: H01L

Claim:
1. A method comprising: forming a first hard mask layer over a semiconductor device layer; forming a mandrel layer over the first hard mask layer; patterning the mandrel layer to form a set of mandrels over the first hard mask layer, the set of mandrels having first widths, wherein the patterning the mandrel layer comprises: forming a first spacer layer over the set of mandrels and the first hard mask layer, the first spacer layer having first widths on at least sidewalls of the set of mandrels; forming a second spacer layer over the first spacer layer, the second spacer layer having first widths on at least sidewalls of the first spacer layer; patterning the first spacer layer and the second spacer layer to form a mask pattern; and patterning the first hard mask layer using the mask pattern as a mask.