METHOD OF DETERMINING AN ASYMMETRIC PROPERTY OF A STRUCTURE

摘要

Methods of determining asymmetric properties of structures are described. A method includes measuring, for a grating structure, a first signal and a second, different, signal obtained by optical scatterometry. A difference between the first signal and the second signal is then determined. An asymmetric structural parameter of the grating structure is determined based on a calculation using the first signal, the second signal, and the difference.