Calculation of changes in pattern dimensions to compensate for proximity effects in electron lithography

Abstract

Calculation of changes in pattern dimensions to compensate for proximity effects in electron lithography have been performed for simple patterns (isolated shapes and lines adjacent to large areas). The formulation of intershape and intrashape proximity effects lead to a set of nonlinear coupled equations. Such equations have been solved iteratively and/or graphically for a variety of cases. Results for isolated lines are in good agreement with empirically determined values that are reportedly being used in electron lithography. Calculated results, for the shapes considered here, can now be used as design rules for pattern generation in electron lithography. The intrinsic quality of corrections (i.e., edge definition) that can be expected from such a technique is discussed. Calculations for interacting shapes show the impracticality of this technique for arbitrary patterns. Despite shortcomings, such a technique may be the only viable technique for electron projection lithography and thus may be useful.