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Expired Canadian patentCanada

Hydrogen etching of semiconductors and oxides

CA 1184478 A · Owner: Western Electric Company, Incorporated · Inventors: Chang, Robert P.H.

CIPO record

Overview

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

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Abstract From the Canadian patent

Abstract, Atomic hydrogen, typically produced in a plasma etches a wide range of materials, including III-V materials and their oxides. GaAs oxide is etched at a faster rate than GaAs, for example, providing significant possibilities for processing integrated circuits and other devices. Silicon is etched preferentially as compared to silicon dioxide or silicon nitride. Native oxides are also conveniently removed by this method prior to other processing steps.

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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 March 26, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 26, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 22, 1982
GrantedMarch 26, 1985
Term endedMarch 26, 2002
Patent numberCA 1184478 A
Classification (IPC)C03C15/00 +2 more

Timeline

Timeline From CIPO dates

1983198519871989199119931995199719992001Application filedFeb 22, 1982Patent grantedMarch 26, 1985Term endedMarch 26, 2002

Sources & verification

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