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. 26, 1989
Filed:
Sep. 23, 1988
Takeo Sato, Kawasaki, JP;
Shinichiro Aoki, Kawasaki, JP;
Katsumasa Yamaguchi, Sagamihara, JP;
Tadashi Kaneko, Sagamihara, JP;
Noboru Nomura, Kyoto, JP;
Keisuke Koga, Osaka, JP;
Kazuhiro Yamashita, Amagasaki, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A system for controlling the relation in position between a photomask and a wafer for use in manufacturing apparatus of a highly integrated circuit such as large scale integration (LSI). The position control system includes a coherent light source for generating two light beams which are different in frequency and polarizing direction from each other. The light beams from the coherent light source is introduced into a first diffraction grating and the diffracted light from the first diffraction grating selectively pass through a telecentric lens system and are led to second and third diffraction gratings respectively disposed on the photomask and the wafer. Light beat signals are obtained in correspondance with the diffracted light from the second and third difraction gratings and the position relation between the photomask and wafer is controlled on the basis of the phase difference between the obtained light beat signals which corresponds to the position difference between the photomask and the wafer.