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Expired Canadian patentCanada

Process for etching holes

CA 1101765 A · Owner: International Business Machines Corporation · Inventors: Chan, See A.; Berkenblit, Melvin; Reisman, Arnold

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

Abstract of the Disclosure A method for etching at least one aperture having a defined crystallographic geometry in single crystals which includes masking the crystal to protect predetermined portions thereof from being etched, and then anisotropically etching with a mixture of sulfuric acid and phosphoric acid.

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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 May 26, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 26, 1998.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJune 13, 1978
GrantedMay 26, 1981
Term endedMay 26, 1998
Patent numberCA 1101765 A
Classification (IPC)C09K13/04 +2 more

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedJune 13, 1978Patent grantedMay 26, 1981Term endedMay 26, 1998

Sources & verification

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