Directed self-assembly with density multiplication of block copolymer via controlled solvent annealing

We report density multiplication of chemically patterned template employing highly segregating polyhedral oligomeric silsesquioxane (POSS) containing block copolymer (PMMA-bPMAPOSS) for extending the technique to smaller dimensions than that attained by PS-b-PMMA. PMMA-b-PMAPOSS which self-assembles into hexagonally closed packed (hcp) array of dots with lattice spacing d=13nm was spin coated on the chemical template with doubled hcp lattice spacing d=26nm, and annealed under controlled CS$_{2}$ atmosphere. By tuning the swell ratio of PMMA-b-PMAPOSS, ordered array of dots with d=13nm, which correspond to 3.5Tbit/in$^{2}$ was obtained by multiplying pattern density of the chemical template in a factor of 4. This work was supported by New Energy and Industrial Technology Development Organization, Japan.