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Expired Canadian patentCanada

Method for passivating an undercut in semiconductor device preparation

CA 1238118 A · Owner: International Business Machines Corporation · Inventors: Ma, William H.; Ahlgren, David C.; Revitz, Martin

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

A method, useful in fabricating semiconductor integrated circuits, for passivating an undercut formed by etch-back of a silicon dioxide layer under a diverse insulator film is disclosed. The method includes the step of coating the device with a thin, conformal film to a thickness sufficient only to line, without refilling, the lateral walls of the undercut region.

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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 June 14, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 14, 2005.
  • 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 12, 1986
GrantedJune 14, 1988
Term endedJune 14, 2005
Patent numberCA 1238118 A
Classification (IPC)H01L21/42 +2 more

Timeline

Timeline From CIPO dates

1987198919911993199519971999200120032005Application filedFeb 12, 1986Patent grantedJune 14, 1988Term endedJune 14, 2005

Sources & verification

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