BLOCK COPOLYMERS AS LITHOGRAPHIC MATERIALS

Block copolymers consist of two or more polymer types connected as distinct strands. When incompatible blocks are combined, then phase separation can occur. In resist design, this offers the possibility of combining two distinct resist functions such as imaging and etch resistance using separate phases in a single polymer. Such separation of function may offer benefits in terms of dimensional stability, etch behavior and development characteristics. A series of 193nm imageable block and random copolymer resists based on t-butyl methacrylate and a silicon-containing methacrylate were studied to test these concepts and are reported here.