Patent ID: 7935639

Claim:
A method used to form a semiconductor device, comprising: forming a plurality of vertically oriented first support features, wherein each feature comprises first and second sidewalls and the first support features are formed to have a first pitch; forming a plurality of first mask spacers, wherein one first mask spacer is formed on each first support feature sidewall, and each first mask spacer comprises an exposed, vertically oriented sidewall; forming a plurality of vertically oriented second support features, wherein one second support feature is formed on the exposed, vertically oriented sidewall of each first mask spacer, and each second support feature is separated from an adjacent second support feature by a gap; forming a plurality of second mask features, wherein one second mask feature is formed within each gap; and removing the first and second support features and leaving the first and second mask spacers to provide an etch pattern, wherein the first and second mask features have a second pitch, and the first pitch is about three times the second pitch.