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:
Apr. 23, 1985
Filed:
Sep. 19, 1983
Keiichiro Sakato, Kawasaki, JP;
Nippon Kogaku K.K., Tokyo, JP;
Abstract
In the printing of an IC circuit pattern on a wafer or photo mask, a system performs an exposure control by measuring the amount of light passed through a shutter and controlling the opening and closing operations of the shutter. The system includes means whereby a superposed measurement of an exposure light quantity during the opening operation of the shutter or the time interval between the time that the opening is started and the time that the opening is completed is effected by preliminarily raising the quantity by an amount corresponding to an excessive exposure light quantity during the shutting operation of the shutter or the time interval between the time that the shutting is started and the time that the shutting is completed, thereby controlling the shutter up to the maximum speed determined by the characteristics of a mechanism itself including the driving system of the shutter.