Specialized scatterometry methods for two types of gratings with distinct groove profiles

Abstract

This paper focuses on specialized scatterometry methods for two types of featured grating structures: highly asymmetric triangular grating on a transparent substrate (type I), and standing-wave photoresist mask grating on a reflective substrate (type II). Compared with the conventional microstructures occurring in semiconductor metrology, both type I and type II have distinct groove profiles, which makes their specialized scatterometry methods also different from the conventional ones. Combining with two specific cases, by using the asymmetry of triangular profile in type I grating, and the strong dispersion property of the specific substrate in type II grating, the paper shows the feasibility of specialized scatterometry methods with high profile reconstruction sensitivity.