Patent ID: 7262837

Claim:
Method for characterizing embedded microstructures with critical dimensions of between 10 μm and 100 μm, the method comprising: (a) providing polarized light, (b) focusing the polarized light onto a predetermined two-dimensional region from a predetermined number of two-dimensional regions at a predetermined number of angles on a wafer which contains the embedded microstructures, (c) focusing the light, scattered by the respective region on the wafer, onto a detector with the aid of a focusing unit, (d) interposing a polarization filter between the focusing unit and the detector, (e) recording intensity spectra for a specific number of polarization planes, angles of incidence and a specific wavelength region, (f) calculating the ellipsometric parameters Ψ and Δ for a specific wavelength region, (g) determining the ellipsometric parameters after the method steps (a)-(f) for the remaining predetermined two-dimensional regions of the wafer, (h) storing the ellipsometric parameters Ψ and Δ for the specific number of angles φ and the two-dimensional regions of the wafer in a data record, (i) comparing the data record with the predetermined reference data records from a reference data library, and (j) determining the reference data record which corresponds most highly to the data record in accordance with a predetermined criterion for providing characterization of embedded microstructures to a database, wherein the most highly corresponding reference data record is that which has the smallest metric distance on the measured data record.