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. 04, 1995
Filed:
Nov. 26, 1993
Manabu Ohno, Kasugai, JP;
Akio Yamada, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Fujitsu VLSI Limited, Kasugai, JP;
Abstract
A charged particle beam exposure system checks for the shape of the charged particle beam shaped by a mask by causing a scanning of a marker pattern provided on a substrate along a scanning path. The reflected electrons emitted from the substrate are detected, and the shape of the charged particle beam is obtained based upon the profile of the reflected electrons along the scanning path. By comparing expected pattern of the reflected charged particles, one can detect anomaly in the beam shaping aperture on the mask, wherein the step for comparing the observed pattern and the expected pattern includes a step of pattern matching for shifting the patterns with each other for seeking a minimum of unoverlapped area of the patterns. When the difference between the observed pattern and the expected pattern exceeds a threshold in the state that the unoverlapped area is minimized, an alarm produced with the information indicative of the location of the pattern wherein the threshold has been exceeded.