Fast imaging algorithm for simulating pattern transfer in deep-UV resist and extracting postexposure bake parameters

This paper presents a simulator, RIAR (Rapid Imaging Analysis for Resists), for fast imaging resist profiles given a post exposure bake (PEB) model. First, the aerial image profile on the surface of the resist is obtained through SPLAT. Then the image profile is converted into the resist pattern after PEB and develop by solving a given 2-dimensional PEB model, which is usually a 2-D partial differential equation (PDE) system. The 2-D PDE system is taken as an image transform and is solved by iteratively approximating the solution with 3- variable polynomial on space and is much faster than the traditional PDE solver. The time complexity of RIAR and STORM are compared with respect to reaction rate, diffusivity, simulation scale, etc. RIAR achieves a speed up of 5 to 7 times STORM, maintaining the precision. In addition, RIAR consumes much less memory and can simulate domains of 9,000 nodes on a DEC Alpha 600 MHz, 256 MB DRAM workstation in a reasonable time. An example of applying RIAR in line-end shortening simulation is also given.