Simulation of optical lithography from distorted photomasks

Simulation of photomask patterning process and optical lithography at wafer level has been combined to investigate the influence of a distorted photomask feature on final photoresist image. Unlike the previous optical lithography simulations which were based on ideal mask designs, the optical lithography simulation presented in this paper is based on distorted masks. The distorted mask comes from electron beam lithography simulation or laser direct write simulation. Proximity effects in e-beam lithography or laser direct write has been taken into account. The results have shown that optical proximity effect is worsened if a distorted mask is used in the optical lithography simulation, instead of an ideal mask.