Patents Assigned to Fujuitsu Limited
  • Patent number: 5966200
    Abstract: The present invention is a charged particle beam exposure apparatus comprising: a column portion in which an optical system for a charged particle beam is disposed; a chamber to be coupled with the column portion; a movable sample stage located in the chamber for mounting a sample thereon; and a stage position measurement device, having an optical path for measurement, along which a laser beam having a predetermined frequency is projected and is reflected by reflection means provided on the sample stage, and an optical path for reference, which in length almost equals a distance between a starting point of the optical path for measurement and the origin of the optical system in the column portion and for which the length is increased at a rate substantially consistent with a thermal expansion coefficient as material of the chamber is expanded, for measuring a change in position of the sample stage by employing a laser optical signal for measurement, which passes along the optical path for measurement, and a r
    Type: Grant
    Filed: October 10, 1997
    Date of Patent: October 12, 1999
    Assignees: Fujuitsu Limited, Advantest Corporation
    Inventors: Kenichi Kawakami, Tatsuro Ohkawa, Kazushi Ishida, Akiyoshi Tsuda