摘要
In integrated circuits manufacturing, specific structures are used as tools to evaluate the quality of the lithographic process, and the shape of these structures is often described by a few parameters, of which in particular the side-wall angle suffers from considerable inaccuracies. Using scalar diffraction theory, we investigate whether a properly shaped cylindrically focused probing beam could increase the ability to detect tiny changes in this angle in the case of a cliff-like structure, modeled as a phase object. This paper describes the theoretical formulation used to calculate the optimized beam and compares its performance with the case of a focused plane wave.
- 出版日期2017-1-1