Patent ID: 8426121

Claim:
A method for self-aligned spatial frequency doubling in one dimension comprising: forming a film stack over a substrate, wherein the film stack comprises a first pattern of a sacrificial material having a first pitch p; forming a conformal material by consuming a portion of the first pattern of the sacrificial material such that the conformal material has a substantially uniform thickness U-shape to surround each remaining portion of the sacrificial material, wherein a sidewall thickness of the substantially U-shape of the conformal material is about p/4 and each remaining portion of the sacrificial material has a width of about p/4; depositing a polymer material over the conformal material to fill spaces between adjacent portions of the conformal material; etching a portion of the polymer material and etching a top portion of the conformal material to expose a top portion of the sacrificial material; and removing remaining portions of both the polymer material and the sacrificial material such that remaining portions of the conformal material form a second pattern having a pitch of p/2.