US Patent 7790045 Formation of close-packed sphere arrays in V-shaped grooves

The present invention relates to the self-assembly of a spherical-morphology block copolymer into V-shaped grooves of a substrate. Although spherical morphology block copolymers typically form a body-centered cubic system (bcc) sphere array in bulk, the V-shaped grooves promote the formation of a face-centered cubic system (fcc) sphere array that is well ordered. In one embodiment, the (111) planes of the fcc sphere array are parallel to the angled side walls of the V-shaped groove. The (100) plane of the fcc sphere array is parallel to the top surface of the substrate, and may show a square symmetry among adjacent spheres. This square symmetry is unlike the hexagonal symmetry seen in monolayers of spherical domains and is a useful geometry for lithography applications, especially those used in semiconductor applications.