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. 27, 1990
Filed:
Sep. 13, 1989
Kazumitsu Nakamura, Katsuta, JP;
Yukio Yoshinari, Toukai, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An electron beam lithography apparatus having an external magnetic field correcting device comprises an electron gun for irradiating an electron beam onto a semiconductor wafer, a electron beam column made from a high magnetic permeability material disposed around the electron beam, a coil equipped on the electron beam column, a magnetic sensor for detecting an external magnetic field which is disposed at the outside of the electron beam column, a stage for mounting and moving the semiconductor wafer, a position detecting means for detecting the position mark on the stage, a correcting device for generating a correcting signal based on the outputs from the magnetic sensor and the position detecting means, and a current adjusting device for adjusting a correcting current flown into the coil according to the correcting signal from the correcting device so as to compensate a rotational deviation of the electron beam caused by the external magnetic field. The electron beam lithography apparatus is obtained at a low cost and results in high positioning accuracy without requiring a covering of a high magnetic permeability material around the electron beam lithography apparatus.