Guiding Template Design for Lamellar DSA with Multiple Patterning and Self-Aligned Via Process

Directed self-assembly (DSA) with block copolymers (BCP) has become a promising lithography technology for generating tiny features in integrated circuits. There have been many existing studies investigating the design methodologies using cylinder-forming BCP for via/contact layer manufacturing. However, cylindrical DSA suffers from the limited natural pitch of generated holes and the displacement errors due to guiding template distortions. Consequently, only few feasible hole patterns are manufacturable with a template and the unsatisfactory yield is still one of the major concerns. On the other hand, lamellar DSA using lamella-forming BCP emerges as another solution for hole generation, which in combination with the self-aligned via (SAV) process is immune to hole displacement errors and able to produce various linear hole patterns. In this paper, we propose the first work of guiding template design for lamellar DSA by using the SAV process and multiple patterning lithography (MPL). An integer linear programming (ILP)-based approach and a heuristic method are respectively proposed that consider the design constraints induced by lamellar DSA with SAV. Experimental results demonstrate the optimality of the ILP-based approach, and the heuristic method can also efficiently derive near-optimal solutions.