Silicon-Containing Block Copolymers for Sub-20 Nm Pitch Patterning

Block copolymers demonstrate potential in next-generation lithography as a solution for overcoming the limitations of conventional lithographic techniques. Ideal block copolymer materials for this application can be synthesized on a commercial scale, have high χ-parameters, promoting self-assembly into sub-20 nm pitch features, and have high etch contrast between the domains for facilitating pattern transfer. Block copolymers that contain silicon in one domain are attractive materials for nanopatterning since they often fulfill these requirements. Here, we describe a new silicon-containing block copolymer system, poly(trimethylsilyl styrene-block-D,L lactide) (PTMSS-b-PLA),  synthesized by a combination of anionic and ring-opening polymerization techniques. Due to the large difference in surface energies between the blocks in silicon-containing materials, a neutral surface treatment and solvent annealing or top coat materials are generally required to achieve perpendicular orientation. The processing conditions required to promote perpendicular orientation of sub-20 nm pitch PTMSS-b-PLA, direct the self-assembly, and transfer the block copolymer pattern into the underlying substrate will be presented.