Curve evolution models for real-time identification with application to plasma etching

It is desirable, in constructing an algorithm for real-time control or iden tification of free surfaces, to avoid representations of the surface requir ing mesh refinement at corners or special logic for topological transitions . Level set methods provide a promising framework for such algorithms. In t his paper we present: 1) A mathematical representation of free surface moti on that is particularly well-suited to real-time implementation; 2) a techn ique for estimating an isotropic and homogeneous normal velocity based on a simple measurement; and 3) an application to a semiconductor etching probl em.