Three-dimensional laser inverse scattering phase method for evaluating microstructure

The 3D laser inverse scattering phase method offers the advantage of measuring a 3D microprofile within the whole area illuminated by laser beam at one time. No scanning process is required as you see in SPM (Scanning Probe Microscope). So, this method finds application where the in-process measurement of a 3D microprofile with accuracy in the nanometer order is required for the process error evaluation. The work reported in this paper deals with development of a new iterative Fourier phase retrieval algorithm based on practical object-domain constraints and actual measurements of a NIST traceable surface topography reference with rectangular pockets 44nm deep at intervals of 10micrometers . The results obtained in the measurements show the validity of the newly developed laser inverse scattering phase method.