Obtaining at least one of a cross-section profile, depth, width, slope, undercut and other parameters of via-holes by a non-destructive technique using an optical system having an illumination system for producing at least one light beam and directing it on a sample in a region of the structure containing at least one via-hole, a detection system configured and operable to collect a pattern of light reflected from the illuminated region, the light pattern being indicative of one or more parameters of said via-hole, and, a control system connected to the detection system, the control system comprising a memory utility for storing a predetermined theoretical model comprising data representative of a set of parameters describing via-holes reflected pattern, and a data processing and analyzing utility configured and operable to receive and analyze image data indicative of the detected light pattern and determine one or more parameters of said via-hole.