Inversion of V(z) Data in the Scanning Acoustic Microscope (SAM) to Determine Material Properties of a Layered Solid

Abstract

A systematic inversion scheme for the characterization of the material properties of a layered solid from measured V(z) data by SAM is proposed. The approach is based on the perturbation of V(z) function and two iterative procedures: the well-known damped least-squares [DLS] method and the pseudo-second-derivative [PSD] method. By using these methods, we have successfully obtained the inversion solutions of V(z) inversion problem from the theoretical simulation test and from a practical measured V(z) data. Furthermore, the generalized inverse approach is also applied to V(z) problem in order to provide the designer with some useful means for evaluation in the inversion course.