Patent ID: 8918742
Filing Date: 2014-12-23
Classification: G03F,G06F

Abstract:
1. A method, implemented by a computer, selecting a set of test patterns for being imaged via a projection lithography system, the set of test patterns having a predetermined characteristic of a lithography response to a predefined wavefront aberration term of the projection lithography system, the predefined wavefront aberration term mathematically representing a characteristic of a wavefront aberration of the lithography system, the method comprising the steps of: a) generating a mathematical series expansion as an approximation of the lithography response as a function of the predefined wavefront aberration term; b) selecting a set of selected expansion terms from the mathematical series expansion; c) generating a cost function comprising the selected expansion terms; d) solving, using the computer, the cost function to define coefficients corresponding to the predefined wavefront aberration term while constraining at least part of the unselected expansion terms substantially to zero; and e) selecting the set of test patterns from among a group of patterns using the coefficients.