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. 08, 1993
Filed:
Feb. 07, 1992
Applicant:
Inventor:
Tsutomu Miyatake, Kiyose, JP;
Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01J / ;
U.S. Cl.
CPC ...
2502014 ; 356401 ;
Abstract
A double-focus detector utilizing a lens system having axial chromatic aberration vertically illuminates a mask and a wafer disposed at a minute interval in the direction of the optical axis of the lens system. The mask is illuminated with a single ray of wavelength 500 nm or more and the wafer is illuminated with a given band flux or a plurality of rays of wavelength larger than that selected for the mask and one of focus planes of the lens system is an image forming plane of the single ray and the other focus plane of the lens system is the same image forming plane of the given band ray or the plurality of rays so that the relative position between the mask and the wafer can be detected.