Optical testing of fine grating structures

The ability to measure the relief parameters and the absolute position accuracy of micrometer-sized structures is of obvious importance, not only to determine if the desired structure has been realized, but also to optimize the fabrication process. In this paper a simple characterization method is presented allowing fast and non-destructive testing of phase and amplitude gratings over large areas. Local line width and position errors can be detected. The theoretical modeling is based on rigorous diffraction theory.