Arbitrary cross sections and stack forms measurement simulations for the semiconductor circuits by scatterometry

Abstract

This paper shows the basic numerical calculation methods for measuring line widths and shapes between 45-80nm using normal and oblique incident light waves to control the resist and silicon line widths for the next-generation semiconductor circuits. The shape measurement method by no destruction and no contact, using the light wave scattering method is called "Scatterometry". While using scatterometry with the actual manufacturing process, it is necessary to compare the characteristics in proportion to the trench shape with the measured values in the real-time. In this paper, we calculate the scattering characteristic from the resist trenches that are put on the silicon substrate. Arbitrary shape groove regions are divided into multilayers using step approximations. The electromagnetic field in each layer can be expanded into eigenmodes of Maxwell's equations. Then, the scattering matrices are obtained. Here, we use the generalized scattering matrix method for the multi-step connection and propose the time shortening method for seeking the groove shapes. Next, the 3D rectangular and arbitrary shape grooves analysis is carried out by considering the oblique incidence using RCWA and FDTD, respectively.