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:
Aug. 14, 1990
Filed:
Jan. 25, 1990
Shigeru Maruyama, Kawasaki, JP;
Shunsuke Fueki, Yokohama, JP;
Horonobu Kitajima, Yokohama, JP;
Takashi Kiuchi, Tsukuba, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A system for aligning a mask and a semiconductor wafer comprises radiation source for producing a radiation beam, a dual focus linear Fresnel zone plate provided on the mask for focusing the radiation beam incident thereto on a surface of the semiconductor wafer which comprises a first part having a first focal length and a second part having a second focal length substantially smaller than the first focal length, a diffraction grating provided on the surface of the semiconductor wafer in correspondence to the dual focus linear Fresnel zone plate for diffracting the radiation beam focused thereon, a detector held with a predetermined relationship with respect to the radiation source and the mask for detecting the diffracted beam, a movable stage for supporting the semiconductor wafer, and a controller for moving the stage means responsive to an output signal of the detection means.