Study of Cut Mask Lithography Options for Sub-20nm Metal Routing

Printing contact-like cut mask form the line end of very dense pitches is imposing a significant challenge to lithography. Various lithography options including optical multi-patterning and EUV have been considered for sub-20nm half pitch metal line cut process. Different lithography solutions of cut mask will impose different design restrictions and thus lead to different scalability of chip. In this paper, we will study routing limitations of sub-20nm half pitch metal lines cut with various optical and EUV lithography options. Key metal routing rules for each cut mask option will be derived based on study of forbidden cut mask configurations. The associated logic area impact will be derived based on real digital design.