A geometric model for active contours in inverse lithography

We propose a new model for active contours in inverse lithography based on a geometric partial differential equation. By cognitive analogy to the classic ‘snakes” model, the closed parametric contour of the interesting layout pattern is evolved under smoothness control, the influence of a distance-metric minimizing image force and an additional distance-regularized level-set (DRLS) pressure force. Numerical implementation is performed locally in the vicinity of zero levelsets with additive operator splitting (AOS) based semi-implicit differencing tenable for sufficient large stepsizes. Simulation results show that the computation efficiency is improved with reduced optimization dimensionality and the convergence efficiency is improved with sufficiently large stepsize when semi-implicit scheme is applied.