Patent ID: 8248621
Filing Date: 2012-08-21
Classification: G01N

Abstract:
1. A method for the optical characterisation of repeat units repeated in a regular manner so as to form a diffraction structure, each repeat unit comprising at least one geometric pattern, each of said patterns being produced, at least in part, using a porous material, said method comprising: determining the geometric parameters of said patterns; performing a scatterometric acquisition using an optical measurement system of the experimental optical response of said diffraction structure placed in a chamber at a given pressure, a presence of an adsorbable gaseous substance in said chamber causing condensation of said adsorbable gaseous substance in at least one part of open pores of the patterns of the structure; and determining a theoretical optical response of said diffraction structure from the determined geometric parameters and by adjusting an optical index of the material of an area of each of said patterns, in which the adsorbable gaseous substance has condensed, so as to make a difference between said experimental response and said theoretical response less than or equal to a given threshold.