Integration of optical proximity correction strategies in strong phase-shifter design for polygate layers

In this paper we discuss some of the problems encountered when implementing 2-mask strong phase shifter designs for the poly gate level in logic designs. Experimental results are presented showing pattern fidelity for different reticle designs. Simulations are presented indicating the improvement in pattern fidelity that can be expected from using OPC. PSM assignment and model-based OPC correction are performed by the Calibre-OPC tool from Mentor Graphics. In conclusion we show that while fairly simple designs can be used to achieve 250nm design rules (—l5Onm gates), in order to achieve both pattern fidelity as well as small feature size it is necessary to use OPC to correct for pattern distortion for design rules of 1 8Onm and below.