Topography based patterning

A mask having features formed by self-organizing material, such as diblock copolymers, is formed on a partially fabricated integrated circuit. A copolymer template, or seed layer, is formed on the surface of the partially fabricated integrated circuit. To form the seed layer, diblock copolymers, composed of two immiscible blocks, are deposited in the space between copolymer alignment guides. The copolymers self-organize, with the guides guiding the self-organization and with each block aggregating with other blocks of the same type, thereby forming the seed layer. Supplemental diblock copolymers are deposited over the seed layer. The copolymers in the seed layer guide self-organization of the supplemental copolymers, thereby vertically extending the pattern formed by the copolymers in the seed layer. Block species are subsequently selectively removed to form a pattern of voids defined by the remaining block species, which form a mask that can be used to pattern an underlying substrate.