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:
Nov. 03, 1981
Filed:
Oct. 22, 1979
Hiroshi Nishizuka, Kodaira, JP;
Susumu Komoriya, Tachikawa, JP;
Koyo Morita, Higashimurayama, JP;
Takayoshi Osakaya, Kodaira, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A wafer projection aligner comprises an optical system for projecting a radiation pattern onto a surface of a semiconductor wafer and a wafer position setting apparatus for positioning the wafer at a position within a focal depth of the optical system for allowing printing of a fine pattern on the wafer. The wafer position setting apparatus includes paralleling means provided with three leveling pads defining a reference plane, air micrometers having a plurality of nozzles opened at least in the vicinity of respective ones of the leveling pads for measuring the distance between the wafer surface and the reference plane in a non-contacting manner, wafer leveling mechanism having a semispherical seat member for holding the wafer and adapted to be vertically movable between the reference plane and the focal plane, and control apparatus for controlling the wafer leveling mechanism so that a focal plane of the wafer is set on the basis of the measured convexity or concavity of the wafer surface as measured by air micrometer, when the parallelism of the wafer as measured by the air micrometer lies within a predetermined standard range.