Patent ID: 8280693

Claim:
A nondestructive analysis for a periodic structure, comprising steps of: (a) illuminating a real periodic structure and measuring, by a detector, at least one physical property related to reflectivity or transmittance of the real periodic structure in response to the illumination; (b) calculating, by a processor, at least one physical property related to at least one of reflectivity or transmittance of a virtual periodic structure in response to the illumination, by setting the virtual periodic structure having a repeated shape, one-dimensionally, two-dimensionally or three-dimensionally and at least a horizontally repeating period, by dividing the virtual periodic structure into vertically stacked N layers, by defining a zero-th order structure and a perturbed structure from the virtual periodic structure, said perturbed structure being obtained by geometrically or physically changing the zero-th order periodic structure in a perturbation region, by calculating the zero-th order reflected or transmitted wave when light is incident on the zero-th order structure, by discretizing the Lippmann-Schwinger equation using M-th order interpolation with at least one divided layer of the virtual periodic structure, wherein 2 ≦M ≦N, by calculating the perturbed reflected or transmitted wave from the discretized Lippmann-Schwinger equation, and by calculating the perturbed reflectivity or transmittance from the zero-th order reflected or transmitted wave and the perturbed reflected or transmitted wave; and (c) comparing the at least one physical property related to the reflectivity or the transmittance being measured in the step (a) with the corresponding at least one physical property related to the at least one of reflectivity or transmittance being calculated in the step (b); wherein the step (b) further comprises steps of: partitioning the N layers of the virtual periodic structure into X sections, wherein 1 ≦X ≦(N−1), and discretizing the Lippmann-Schwinger equation using Mi-th order interpolation with the partitioned sections wherein 1≦Mi ≦N.