Pattern transfer by directed self-assembly (dsa) of block copolymers (bcps)

A method for patterning an exposed resist layer that is over a substrate, wherein the exposed resist layer comprises an exposed region and an unexposed region, the method comprising:

• applying a block copolymer over the resist layer;
• heating the block copolymer to initiate a directed self-assembly (DSA) process using the exposed region and the unexposed region as a template to segregate a polar region of the block copolymer from a non-polar region of the block copolymer;
• removing the polar region or the non-polar region to form a patterned mask over the resist layer;
• and
• etching the resist layer through the patterned mask.

A method, comprising:

• exposing a resist layer with extreme ultraviolet (EUV) radiation to form an exposed region and an unexposed region;
• applying a block copolymer over the resist layer;
• heating the block copolymer to allow for a directed self-assembly process to segregate a polar region of the block copolymer from a non-polar region of the block copolymer, wherein the exposed region and the unexposed region have chemical differences that provide a template to enable the directed self-assembly process;
• removing the polar region or the non-polar region to form a patterned mask over the resist layer;
• and
• etching the resist layer to form a patterned resist layer using the patterned mask.