Patent ID: 8623223

Claim:
A method using a block copolymer (BCP) for making a master disk for use in imprinting magnetic recording disks comprising: providing a substrate having a center; depositing on the substrate a polymeric neutral layer; patterning the neutral layer into a pattern of sets of generally radial stripes about said substrate center and circumferential gap regions, each stripe set having the same number of stripes and the stripes in each set being generally equally angularly spaced with a stripe pitch of approximately nL 0 , where n is an integer equal to or greater than 2 and L 0 is the bulk period of the BCP, and the gap regions having the same circumferential gap width greater than 2 L 0 ; forming on the patterned neutral layer a BCP having a bulk period L 0 , the BCP material being guided by the stripes to self-assemble into alternating first and second radial lines of alternating first and second BCP components arranged as lamellae perpendicular to the substrate, the BCP self-assembling in the gap regions as alternating first and second components of the BCP arranged as lamellae parallel to the substrate; and removing the second component, leaving sets of generally equally angularly spaced generally radial lines of first component on the substrate.