Verified Optical Scatterometry Model for Line-Space and Metal-Gate Structures

Metrology is an important area in semiconductor manufacturing. As the dimensions of nanostructure rapidly shrink, the optical critical dimension (OCD) metrology has become more and more critical. Owing to OCD's fast, non-destructive, and in-line-compatible advantages, it has proved to be an effective tool to detect three-dimensional (3D) periodic structure's geometry at several-nanometer scale. In this paper, we introduce a verified and effective method to realize the simulation of optical scatterometry. We use rigorous coupled-wave analysis (RCWA) due to the speed of the algorithms. By comparing our scatterometry model with the experimental data, its validity and accuracy will be proved. We provide enough signal channels as the intensity of the diffracted light is measured as a function of incoming angle and wavelength. Then, we use our verified algorithm to simulate a high-k metal gate model, and comparing the detective sensitivity under different illumination conditions.