Patent ID: 9091942
Filing Date: 2015-07-28
Classification: G03F

Abstract:
1. A method of measuring line edge roughness, comprising: performing a plurality of rigorous-couples-wave-analysis simulations of absorption with multiple diffraction patterns; analyzing a physical semiconductor structure for line edge roughness with a scatterometry tool; identifying one of the plurality of rigorous-couples-wave-analysis simulations as a best-fit model based on a minimum residual between signals that are diffracted from the physical semiconductor structure and received from a detector in the scatterometry tool, and simulation data of absorption from the plurality of rigorous-couples-wave-analysis simulations of absorption with multiple diffraction patterns; using the best-fit model to derive an optimal extinction parameter value for a semiconductor structure; and associating the best-fit model to line edge roughness to identify the model that most closely models the absorption of the physical semiconductor structure; and wherein deriving an optimal extinction parameter value comprises: determining a real component of the optimal extinction parameter value based on natural absorption in an ideal sample that does not include line edge roughness; and determining a line edge roughness component of the optimal extinction parameter value, and wherein the best-fit model is used to manufacture a semiconductor integrated circuit.