MORPHOLOGICAL-STUDIES OF SPIN-COATED FILMS OF POLY(STYRENE-BLOCK-METHYL METHACRYLATE) COPOLYMERS BY ATOMIC-FORCE MICROSCOPY

The surface structure of very thin (15-20 nm) spin-coated films of a s ymmetrical poly(styrene-b-methyl-methacrylate) block copolymer on sili con and mica is analyzed by atomic force microscopy (AFM). The films s how a surface corrugation of a very regular approximately 100 nm later al periodicity and approximately 6-8 nm amplitude. Film thickness is m easured by AFM at induced film defects and checked by ellipsometry. XP S shows that both blocks are at the film surface. Selective degradatio n of the methyl methacrylate block is used for contrast enhancement an d allows to assign poly(styrene) to the elevated surface regions and p oly(methyl methacrylate) to the substrate/film interface. Friction int eractions of the AFM tip with the film surface may be used to induce h igh orientational ordering of the morphological pattern perpendicular to the fast scan direction.