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:
Oct. 24, 2000
Filed:
Oct. 23, 1998
Yasushi Sugiyama, Minamikawachimachi, JP;
Mikichi Ban, Hagamachi, JP;
Takehiko Suzuki, Satsute, JP;
Masaru Nyui, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method and apparatus for measuring the thickness of a film layer provided on a predetermined surface includes a step and device for detecting light reception signals of interference light of different wavelengths generated when light illuminates the film layer on the predetermined surface, a step or device for performing a first process for obtaining an approximate value for the film thickness by selecting a combination of solutions with the closest values from among solutions for the film thickness obtainable from at least three of the light reception signals corresponding to the respective wavelengths, and a step or device for performing a second process for obtaining an exact value for the film thickness by selecting a combination of solutions with the closest values from among solutions for the film thickness obtainable from all the light reception signals corresponding to the respective wavelengths. The second process is performed on the basis of the approximate value and with a restricted range for selection of the combination.