Inverse scattering algorithm for profile reconstruction of a buried defect beneath a dielectric rough surface based on the domain-boundary integral hybrid method.

ABSTRACT

A reconstruction algorithm for the defect profile beneath a dielectric rough surface using scattered far fields is proposed. This is a fundamental technique for optical measurements, such as diffraction tomography, for defect inspection of microfabricated devices. In general, the profile reconstruction process is considerably time consuming. We propose a domain-boundary integral hybrid method to reduce the number of operations while maintaining the rigor of scattering; the polarization properties, scattering, and multiscattering in the sample are considered. We present reconstruction simulations to validate the proposed algorithm. The reconstruction limit as well as its dependency on sample illumination and rough surface shape are also discussed.