A fast path-based method for 3-D resist development simulation

A three-dimensional (3-D) remaining resist profile often needs to be estimated and examined especially for nanoscale feature. However, conventional methods, such as the cell removal method and fast marching method, require intensive computation, and therefore are too time-consuming to be employed for large patterns such as a mask or an iterative procedure such as proximity effect correction (PEC). In this paper, a new method for 3-D resist development simulation has been developed for fast and accurate simulation of simple patterns such as lines and rectangles. It employs the concept of ‘‘development paths’’ to model the development process. In order to reduce the simulation time, each path is examined individually without a time-consuming iterative procedure which is adopted by conventional methods. An adaptive scheme has also been incorporated into the proposed simulation method, which further reduces the simulation time without sacrificing simulation accuracy substantially. The simulation results show that the proposed method achieves resist profiles well matched with those by conventional methods, even for more general patterns, but reducing simulation time by orders of magnitude, and the speedup is larger for a larger pattern. Also, the accuracy of the proposed method has been verified experimentally. 2014 Elsevier B.V. All rights reserved.