The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 11, 1997
Filed:
Feb. 07, 1996
Harrison H Barrett, Tucson, AZ (US);
Wyko Corporation, Tucson, AZ (US);
Abstract
An improvement to phase-shifting interferometry that consists of the addition of a pupil mask with two parallel slits and a polarizer in the optical path of a conventional phase-shifting interferometer. The pupil-mask/polarizer combination is adapted to produce a linearly polarized wavefront of light reaching the sample surface at a predetermined angle of incidence, thereby producing a corresponding phase shift on reflection. The relative orientation of the mask and polarizer can be changed to take measurements with the polarizer parallel or perpendicular to the mask slits, in each case producing a phase shift on reflection related to the test sample's refractive index and extinction coefficient. Four phase-shifting measurements conducted at .pi./2 intervals for each polarization axis yield sufficient interferometric information to map n, k and the height profile of the sample surface. The preferred mask consists of an opaque disk structure having two opposite annular slits approximately 90-degrees wide and with an outer annular radius approximately twice the size of the inner annular radius.