Method and system for measuring a surface of an object comprising different structures using low coherence interferometry

A method for measuring a surface of a substrate comprising at least one structure using low coherence optical interferometry, the method being implemented with a system comprising an interferometric device, a light source, an imaging sensor, and a processing module, the method comprising the following steps:

• acquiring, with the imaging sensor, an interferometric signal formed by the interferometric device between a reference beam and a measurement beam reflected by said surface at a plurality of measurement points in a field of view;
• the following steps being carried out by the processing module:
• distributing the acquired interferometric signals according to homogenous regions of the field of view, where the regions are homogenous according to a predefined criterion;
• for at least one measurement point, identifying a class associated with a reference interferometric signal, representative of a typical structure, from the acquired interferometric signals in the homogeneous region to which the measurement point belongs;
• classifying, by a learning technique, the acquired interferometric signals according to a plurality of identified classes;
• and
• analysing the interferometric signals in order to derive therefrom information on the structure at the measurement points, as a function of the class of each interferometric signal.