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:
Sep. 26, 1995
Filed:
Oct. 12, 1993
Anthony M Ledger, New Fairfield, CT (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
Systems for making thickness measurements in a thin film structure using an incoherently or coherently coupled structured surface. A system is used to measure the thickness of a thin film layer of a thin film structure in which polished and structured surfaces are coherently coupled together. Visible light used to measure the thickness of thin bonded wafers that have a ground upper surface, or infrared light is used to measure the thickness of thick silicon wafers where one surface is ground, and the other is polished. Other systems use a structured surface that is incoherently coupled to a thin film structure in order to illuminate the thin film structure at many angles. The systems produce interference fringes that are detected and recorded, and multispectral pattern matching is used in a computer to compute film thickness based on scattering characteristics included in a library f stored interference patterns.