| abstract |
The present invention is broadly concerned with materials, processes, and structures that allow an underlayer to be imaged directly using conventional lithography, thus avoiding the photoresist processing steps required by prior art directed self-assembly (DSA) processes. The underlayers can be tailored to favor a selected block of the DSA block co-polymers (BCP), depending on the pattern, and can be formulated either to initially be neutral to the BCP and switch to non-neutral after photoexposure, or can initially be non-neutral to the BCP and switch to neutral after exposure. These materials allow fast crosslinking to achieve solvent resistance and possess good thermal stability. |