Corrections to proximity effects in electron beam lithography. I. Theory

Electron lithography at micrometer dimensions suffers from a seemingly fatal problem due to proximity effects. Three corrections techniques are discussed. The self-consistent technique computes the incident electron exposure such that identical average specific fragmentation occurs in each written shape of the pattern. A unique solution, that depends only on the form and on the magnitude of proximity function, is obtained. The unaddressed-region compensation technique attempts to compensate for proximity effects in regions between shapes; this, however, leads to computational complexities and impracticalities. The shape-dimension adjustment technique attempts to compute dimension of exposed shapes such that the shapes developed in the resist will have the designed dimension. A set of nonlinear (and impractical) equations are obtained in this case. The implementation of these techniques and the experimental results obtained therefrom are the subject of the two succeeding papers.