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:
Sep. 20, 1983
Filed:
May. 20, 1981
Applicant:
Inventor:
Herbert E Mayer, Eschen, AT;
Assignee:
Censor Patent- und Versuchs-Anstalt, Vaduz, LI;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
355 77 ; 355 44 ; 355 53 ; 355125 ;
Abstract
In the projection-copying of a mask on a workpiece including a light-reflecting semiconductor substrate, the alignment of mask and workpiece is effected by illuminating marks on the substrate which appear dark relative to a surrounding area. To provide each mark with a contrasting background of sufficient brightness, a partly reflecting surface layer overlying the substrate in that area has a nonuniform optical thickness whereby cancellation of reflections due to interference is limited to isolated regions.