Free Energy Modeling of Block-Copolymer Within Pillar Confinements on Dsa Lithography

To a major candidate and beyond, directed self-assembly (DSA) lithography is investigated on DRAM contact-hole fabrication. We perform a systematic study about behavior of asymmetric PS-b-PMMA block copolymers (BCP) within pillar confinement for DSA and find that selectively removed PMMA contact domain has a different morphology according to chemically modified pillar surfaces. We calculate the perturbation of PMMA contacts by pillar diameter using free energy magnitude model. This established model provides practical engineering insight for present pillar scheme and future graphoepitaxial self-assembly techniques for semiconductor DSA procedure.