Block Copolymer Lithography Glenn H. Fredrickson, UC Santa Barbara, DMR 0603710 Have you ever thought about how the flash memory in your camera or music player is made? More and more, the self-assembly of polymeric materials known as block copolymers are used to define magnetic features at a 5 nanometer length scale – a scale not accessible by conventional “top-down” lithographic techniques. The problem with self-assembly, however, is that it is not perfect, leading to defects in the templated magnetic structure. Our group has been conducting computer simulations to learn how to design polymers and create topographic features on a wafer so that perfect arrays of magnetic dots can be manufactured. For example, the figure at left below shows 100 nm square wells that have been created in silicon using top-down lithography. When block copolymers are placed in the wells they can assemble to produce square lattices of cylindrical or spherical features. We are conducting simulations (at right) to explore the effect of line edge roughness on defects in the self- assembled lattices. Studies like these will provide the scientific understanding necessary to design the next generation of electronic devices.