Systems and methods for inspection and metrology of vertical interconnect access in semiconductor substrates

Abstract

The system includes a light source that emits partially coherent or coherent light split into a reference beam and an object beam and a stage that supports a workpiece in a path of the object beam, that is transmitted through the workpiece. The workpiece includes a vertical interconnect access (VIA) extending from a first side to a second side of the workpiece. A first beam splitter combines the reference beam with the object beam transmitted through the workpiece into a combined beam, and a camera detects the combined beam received. A processor generates an interference image of the workpiece based on the combined beam, determines amplitude and phase information of the object beam based on the interference image, generates a plurality of depth images of the workpiece based on the amplitude and phase information, and determines a critical dimension (CD) of the VIA based on the plurality of depth images.