Optical Lithography in the dominant patterning technology in chip-manufacturing, in which the patterns on mask is transferred to wafer using monochromatic laser. Due to diffraction effects, the patterns on mask is different from the patterns actually printed on wafer. The inverse problem here is: given the desired patterns on wafer, what patterns on mask should be used?
Another typical inverse problem in optical inspection is: given a measured image from inspection tool of a potentially defective mask, find the defect shape on mask.
In this talk, we present a formulation in which the mask is represented using one or multiple level-set function(s), and the problems as an optimization problem with a properly-chosen fit function. This is the so-called Inverse Lithography Technology (ILT), populated by Luminescent technologies, Inc. co-founded by Stanley Osher and others in 2003. We present some of the results obtained using this approach, some of which is highly non-intuitive, and challenges in choosing the proper fit functions and inverse algorithm. By Danping Peng, Tom Cecil, Lin He
Tom Cecil and Lin He, Co-presenters
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