公开(公告)号：FR2276624A1

公开(公告)日：1976-01-23

申请号：FR7515555

申请日：1975-05-09

Applicant: IBM

Inventor： DORAN SAMUEL K ,  PERKIN MERLYN H

IPC: H01J37/147 ,  H01J37/153 ,  H01J37/21 ,  H01L21/027 ,  G05D3/02 ,  H01J37/30

Abstract: The location of a beam of charged particles within a deflection field is determined by its orthogonal deflection voltages. With the location of the beam in the field, correction currents are supplied to a focus coil and to each of a pair of stigmator coils to correct for change of focal length and astigmatism due to the beam being deflected away from the center of its deflection field.