Heterogeneous diffusion model for simulation of resist process

There have been imposed quite incompatible requirements on lithographic simulation tool for OPC, that is it should be enough accurate and enough fast. Though diffused aerial image model (DAIM) has achieved these goals successfully [1,2], rapid transition of lithography into very low k1 and sub-resolution regime makes it very difficult to meet these goals without loss of any of speed or accuracy. In this paper we suggested new modeling method of resist process which is called heterogeneous diffusion of aerial image. First, various examples of CD discrepancy between experiment and simulation with DAIM are suggested. Then the theoretical background of new model is explained and finally CD prediction performance of new model is demonstrated in 60nm 0.29k1 patterning of real DRAM devices. Improved CD prediction capability of new model is observed in various critical patterning of DRAM.