Patent Document ID: 9746315
Application ID: 14733092
Patent Status: 1

Claim One:
1. An optical profilometric method for measuring a sample surface with a single data acquisition scan when local conditions of the surface prevent the formation of interferometric correlograms on portions of the surface, the method comprising the following steps: providing a scanning interferometer configured to split an interferometric beam into an object beam and a reference beam, said interferometer including a source of side illumination; scanning the sample surface through focus while illuminating the sample surface with said object beam and a side illumination beam; acquiring irradiance data produced by said side illumination beam and by interference of the object beam with the reference beam during the scanning step; and processing said irradiance data with an interferometric technique where said data contain correlogram information and with a depth-from-focus mapping technique where the data do not contain correlogram information; wherein said processing step comprises deriving interferometric maps and depth-from-focus maps of corresponding adjacent portions of said surface and merging said interferometric maps and contrast maps to produce a continuous map of said adjacent portions of the surface, and further comprises processing said irradiance data with a depth-from-focus mapping technique also where the data contain correlogram information to derive corresponding depth-from-focus secondary maps, and then utilizing an offset between said depth-from-focus maps and said depth-from-focus secondary maps to align vertically the interferometric maps and the depth-from-focus maps.