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:
Aug. 09, 1994
Filed:
Aug. 04, 1992
Peter B Mumola, Huntington, CT (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
An apparatus (10) that measures the thickness of a thin film layer of a wafer (12) is described. The thickness of the thin film layer is measured by irradiating a reference wafer (22) with a beam (21) of broadband radiation. The reference wafer (22) has a layer structure similar to that of the wafer (12) undergoing measurement, whereby the thin film layer of the reference wafer (22) that corresponds to the thin film layer to be measured is varied over a specific range of known thicknesses. Thus, the incident beam (21) of broadband radiation is reflected from the reference wafer (22) having a unique spectral signature that corresponds to one of these known thicknesses. A reflected beam (23, 25, 27) of unique spectral radiation is projected onto the wafer (12) undergoing measurement, where it is reflected to produce a beam (29) of unique spectral radiation having a characteristic that is indicative of the thickness of the thin film layer to be measured. The characteristic of the beam (29) of unique spectral radiation is captured by a charge coupled device camera (34), and a computer (36) correlates this captured characteristic with one of the known thin film layer thicknesses of the reference wafer (22) to provide an output that corresponds to the thickness of the thin film layer whose thickness is desired to be measured.