公开(公告)号：DE3475452D1

公开(公告)日：1989-01-05

申请号：DE3475452

申请日：1984-05-30

Applicant: IBM

Inventor： FORSTER THEODOR ,  KERN DIETER ,  VETTIGER PETER ,  WILSON ALAN DIXON

IPC: H01J37/305 ,  G03F7/20 ,  H01J37/317 ,  H01L21/027 ,  H01J37/304

Abstract: Data from a computer are supplied to a pattern generator and represent the shape to be produced. The origin coordinates and incremental steps are signalled to a digital-analog converter. The resulting signals are supplied to the electron beam deflection coils (19,21) following amplification (29). A detector determines a signal representing the rate of electron back-scattering. The signal is amplified and applied to a multi-level range coder. The corresponding level signal is applied to a stepping rate selector which produces a corresponding stepping rate correction which corresponds to the signal level. This is converted to an ac voltage for application to a VCO controlling the beam stepping rate signal for the pattern generator.