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:
Jan. 07, 2003
Filed:
Nov. 08, 1999
Kohzo Abe, Annaka, JP;
Nobuaki Iguchi, Kawasaki, JP;
Other;
Abstract
A pair of optical profile measuring systems are located at positions facing to both surfaces of a wafer vertically supported at its edge. A thickness gauge having one or more sensors is located between the optical systems for measuring thickness at several points on the wafer . Each optical system comprises a light emitter for discharging a measuring light beam , a collimator lens for rectifying the light beam into a collimated beam, an optical flat for transmitting the collimated light beam , a light detector receiving the light beams reflected on a surface of the wafer and on a referential plane of the optical flat through the collimator lens and a computer for processing interference fringes which occur between the surface of the wafer and the referential plane of the optical flat . Profiles of main and backside surfaces of the wafer are calculated from interference fringes corresponding to both surfaces of a wafer , and a real shape of the wafer is determined from the profiles in consultation with thickness values measured by the thickness gauge