Lithography simulation: modeling techniques and selected applications

This article reviews standard and advanced modeling techniques in lithography simulation. Rigorous electromagnetic field solvers such as the Waveguide Method and finite-difference time-domain (FDTD) algorithms in combination with vector imaging models predict the image formation inside the photoresist. Semi-empirical macroscopic and microscopic models describe physical and chemical phenomena during the processing of resists. Various local and global optimization techniques are applied to identify the best exposure and process parameters. Several examples demonstrate the application of predictive simulation for the exploration of future lithography options and for the optimization of existing technologies. This includes the consideration of mask material parameters in source/mask optimization, the evaluation and comparison of different options for double exposure and double patterning techniques, and the investigation of mask-induced imaging artifacts in EUV-lithography. Selected examples illustrate the application of lithography simulation for the modeling of cost efficient alternative exposure techniques for special applications of micro- and nanotechnology.