Patent ID: 7088444
Filing Date: 2006-08-08
Classification: G01N,G01R,H01L

Abstract:
1. A method for evaluating a structure that has a plurality of layers, the method comprising: measuring a first reflectance of a first layer in the structure, to obtain a first measurement; measuring a second reflectance of a second layer in the structure, to obtain a second measurement; and comparing the first measurement and the second measurement to determine existence of a defect; wherein the first layer comprises a plurality of traces of conductive material supported by the second layer; wherein the measuring of first reflectance is performed across a group of traces, thereby to obtain in the first measurement an average measure of the first reflectance across traces in the group; wherein the measuring of first reflectance comprises illuminating the structure with a beam comprising electromagnetic radiation having a wavelength greater than a pitch between two adjacent traces in said group; wherein the beam is hereinafter first beam, and the measuring of first reflectance comprises focusing a second beam of electrons, said second beam having intensity modulated at a predetermined frequency; and wherein the measuring of first reflectance further comprises sensing a modulated portion of the first beam.