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:
Jun. 30, 1987
Filed:
Nov. 26, 1985
Atsushi Kikkawa, Osaka, JP;
Noriyuki Kondo, Kyoto, JP;
Dainippon Screen Mfg. Co., Ltd., Kyoto, JP;
Abstract
Apparatus and a method are disclosed for measuring the thickness of a very thin transparent film formed, for example, on a photomask or wafer for an integrated circuit. Diffracted reflected light from a film specimen is converted photoelectrically by use of a one dimensional image sensor array and then by an A/D converter having a resolution of more than 2.sup.10, which allows for discrimination into 1,000 graduations of output level. Enhanced precision in determining film thickness is obtained by utilizing this high discrimination to first determine the variations among individual elements of the one dimensional sensor array and compensating for them, as well as by using known averaging and statistical techniques to generate output for comparison to reference data from film specimens of known thickness.