US Patent 10515801 Pitch multiplication using self-assembling materials

Self-assembling materials, such as block copolymers, are used as mandrels for pitch multiplication. The copolymers are deposited over a substrate and directed to self-assemble into a desired pattern. One of the blocks forming the block copolymers is selectively removed. The remaining blocks are used as mandrels for pitch multiplication. Spacer material is blanket deposited over the blocks. The spacer material is subjected to a spacer etch to form spacers on sidewalls of the mandrels. The mandrels are selectively removed to leave free-standing spacers. The spacers may be used as pitch-multiplied mask features to define a pattern in an underlying substrate.