Exposure and development models used in electron beam lithography

This review examines exposure and development models which are used in electron beam lithography to predict resist profiles. The following topics are discussed: development models of positive polymeric electron resists, in particular, poly-methyl-methacrylate; exposure models based on analytic or Monte Carlo calculations of energy dissipation; comparisons of experimental measurements of linewidth and profile shape and predictions based upon exposure and development models; the dependence of proximity effects on resist and substrate thickness, beam voltage, and substrate material; and finally algorithms used to alter the exposure or pattern shape or both to compensate for proximity effects. The understanding which is gained from the exposure and development models is discussed in terms of fabrication techniques used in electron beam lithography.