Mask and Template Assignment on DSA-MP with Triple BCP Materials Lithography

In the sub-7nm technology nodes, as the mask cost for printing the dense via layers increases dramatically with conventional lithography techniques, triple block copolymer (triple-BCP) materials for directed self-assembly (DSA) lithography is considered as a promising technology to reduce the mask cost. In this paper, we consider triple-BCP and template assignment for triple patterning lithography with DSA. Firstly, we formulate the problem as a maximum weighted independent set (MWIS) problem, and then use the integer linear programming (ILP) to obtain its solution. Furthermore, to gain a better trade-off between runtime and solution quality, we proposed a modification of the Fiduccia-Mattheyses heuristic method (MCFM) to efficiently solve the MWIS problem. Experimental results verify the effectiveness of our method, and indicate that adopting three different BCP materials can dramatically reduce conflict numbers compared with existing works using double BCP materials.