Hybrid lithography optimization with E-Beam and immersion processes for 16nm 1D gridded design

Abstract

Since some of major IC industry participants are moving to the highly regular 1D gridded designs to enable scaling to sub-20nm nodes, how to manufacture the randomly distributed cuts with reasonable throughput and process variation becomes a big challenge. With the help of hybrid lithography, people can apply different types of processes for one single layer manufacturing such that the advantages from different technologies can be combined together to further benefit manufacturing. In this paper, targeting cut printing difficulties and hybrid lithography with electron beam (E-Beam) and 193 nm immersion (193i) processes, we propose a novel algorithm to optimally assign cuts to 193i or E-Beam processes with proper modifications on cut distribution, in order to maximize the overall throughput. To validate our method, we construct our algorithm based on the forbidden patterns obtained from the optical simulation; then we formulate the redistribution problem into a well defined ILP problem and finally call a reliable solver to solve the whole problem. Experimental results show that the throughput is dramatically improved by the cut redistribution. Besides that, for sparser layers, the EBL process can be totaly saved, which largely reduces the fabrication cost.