Straightforward directed self-assembly process flows enabled by advanced materials

A variety of advanced DSA materials have been developed to offer the ease of fabrication and precise control of DSA processes, especially to minimize the number of processing steps and material depositions needed in the DSA implementation. Exemplary materials include spin-on hardmask neutral layer (HM-NL) materials, crosslinkable guiding polymers materials (X-mat), and block copolymers (BCPs) with respective unique combinations of multiple functionalities, e.g., HM-NL materials having etch resistance capability, reflectance control, and non-preferential surface energy to BCP blocks; BCPs with solubility in orthogonal solvents to photoresist, low thermal annealing temperatures required, and no need for top-coat or solvent annealing to get perpendicular orientation. Empowered by these materials, both conventional graphoepitaxy and chemoepitaxy DSA processes can be simplified and enhanced with more potential. For instance, simplified graphoepitaxy DSA by using positive-tone development (PTD) photoresist patterns has been successfully demonstrated. This simplified graphoepitaxy DSA has also led to a facile approach to generate chemoepitaxy guiding patterns.