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:
Mar. 20, 1990
Filed:
Dec. 18, 1987
Raul Y Tan, San Jose, CA (US);
David W Myers, Livermore, CA (US);
Robert G Ozarski, Livermore, CA (US);
John F Schipper, Palo Alto, CA (US);
Michael P Watts, Portola Valley, CA (US);
Other;
Abstract
Two methods for determination of thickness of a film of known material that is mounted on one face of a solid substrate of known material are disclosed, using: (1) inversion of an optical beam reflectivity equation; or (2) determination of the film thickness that minimizes the variance of the optical beam reflectivity, computed at each of a predetermined sequence of optical beam wavelengths. Four methods for determination of the (real) refractive index of a film of known thickness mounted on a face of a solid substrate of known material are disclosed, using: (1) minimization of absolute differences of computed and measured optical beam reflectivity, summed over a sequence of known film thicknesses, for assumed values of the refractive index; (2 and 3) two iterative techniques of promote convergence of an estimate of the index to a final value of the refractive index; or (4) solution of a quadratic equation whose coefficients are slowly varying functions of the solution variable.