Patent Yard Sign in
Expired Canadian patentCanada

Electron-beam exposure apparatus

CA 1284237 C · Owner: Sakamoto, Masahiko · Inventors: Sakamoto, Masahiko; Hoshinouchi, Susumu; Zumoto, Nobuyuki

CIPO record

Overview

Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

Open the CIPO record

Abstract From the Canadian patent

An electron-beam exposure apparatus having a correction function for correcting deflection distortion. The correction function is carried out by the provision of a correcting device including an analog correction unit 35 and a digital correction unit having a memory unit 10 for storing correction data other than data that can be expressed by a cubic function. The capacity of such a memory unit can be made smaller than that of conventional apparatuses.

Read the whole patent

Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted May 14, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 14, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 22, 1988
GrantedMay 14, 1991
Term endedMay 14, 2008
Patent numberCA 1284237 C
Classification (IPC)H01L21/30 +2 more

Timeline

Timeline From CIPO dates

1989199119931995199719992001200320052007Application filedSep 22, 1988Patent grantedMay 14, 1991Term endedMay 14, 2008

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.