Molela Moukara

Introduction of full-level alternating phase-shift mask technology into IC manufacturing

A study to partition a gate level design into an alternating phase shift mask and a chrome on glass trim mask is presented. After determination of important rules for the partitioning by simulation, all investigated gate level pattern could be partitioned, only with slight modifications of the wiring. By application of optical proximity correction (OPC) good gate width and sufficient pattern fidelity control was obtained with the chosen OPC methodology using a calibrated optical model. Nevertheless, several indications of weak spots at two dimensional patterns at extreme defocus are discussed based on experimental data and simulation. To further improve the process window of such pattern, new methods are necessary to detect and prevent such remaining weak spots.