Systems and methods of characterizing wafer shape using coherent gradient sensing (CGS) interferometry are disclosed. The method includes measuring at least 3×106 data points on a wafer surface using a CGS system to obtain a topography map of the wafer surface. The data are collected on a wafer for pre-processing and post-processing of the wafer, and the difference calculated to obtain a measurement of the effect of the process on wafer surface shape. The process steps for processing the same wafer or subsequent wafers are controlled based on measured process-induced change in the wafer surface shape in order to improve the quality of the wafer processing.