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Expired Canadian patentCanada

Surface treatment of a molybdenum screening mask

CA 1260334 A · Owner: International Business Machines Corporation · Inventors: Schick, Henry C.; Mackinnon, Donald A.; Li, Pei-Ching

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Abstract From the Canadian patent

Abstract, Disclosed is a method of treating the surface of a molybdenum mask used for screening a metallized paste pattern to render it smooth and preserve the mask's hardness. The treatment consists of subjecting the mask to a nitridation step by which an ultrathin layer of molybdenum layer is first formed followed by, deposition of a comparatively thick silicon nitride layer thereon. The nitridation step may be accomplished in a plasma deposition system using either forming gas, ammonia or gas mixture of nitrogen and ammonia at a predetermined low temperature and pressure. The silicon nitride deposition may be accomplished in the same system at the same temperature and pressure by …

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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 September 26, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 26, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 27, 1986
GrantedSeptember 26, 1989
Term endedSeptember 26, 2006
Patent numberCA 1260334 A
Classification (IPC)C23C16/34 +2 more

Timeline

Timeline From CIPO dates

1987198919911993199519971999200120032005Application filedJan 27, 1986Patent grantedSep 26, 1989Term endedSep 26, 2006

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