Selective Inverse Lithography (ILT) approach recently introduced by authors has proven to be advantageous for extending life-span of lower-NA 193nm exposure tools to achieve satisfactory 65nm contact layer patterning. We intend to find an alternative solution without the need for higher NA tools and advanced light source optimization. In this paper we explore possible region selection criteria for ILT application based on pitch for a full chip optical proximity correction (OPC). Through studying the impact of a given selection criteria on runtime, resolution, and the process window we recommend an optimal combination. With a justified choice of an ILT selection criteria, we construct a hybrid OPC flow comprising a recursive sequence of direct assist features generation, selective ILT application, layout repair, model OPC and hot spots screening.

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