Implementation of rigorous coupled wave analysis having improved efficiency for characterization

Abstract

Improved optical characterization is provided by organizing the optical modeling calculations such that incident radiation parameters (e.g., wavelength) are varied in the outermost loop of any modeling run. By completing calculations for all combinations of structure parameters at one wavelength before moving to the next wavelength, calculation efficiency can be greatly improved. In particular, with this approach it is not necessary to cache (or re-compute) intermediate results pertaining to different wavelengths, in contrast to conventional approaches. Further improvements in efficiency can be obtained by organizing reflectance calculations such that for any layer L, stored intermediate results pertaining to layers below Lcan be used to calculate optical response as parameters for Land layers above Lare varied. Similarly, transmittance calculations can be organized such that for any layer L, stored intermediate results pertaining to layers above Lcan be used to calculate optical response as parameters for Land layers below Lare varied.