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Expired Canadian patentCanada

Method of manufacturing semiconductor article

CA 2221245 C · Owner: Yonehara, Takao · Inventors: Yonehara, Takao; Sakaguchi, Kiyofumi

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Abstract From the Canadian patent

A method of manufacturing a semiconductor article comprises steps of forming a diffusion region at least on the surface of one of the sides of a silicon substrate by diffusing an element capable of controlling the conduction type, forming a porous silicon layer in a region including the diffusion region, preparing a first substrate by forming a nonporous semiconductor layer on the porous silicon layer, bonding the first substrate and a second substrate together to produce a multilayer structure with the nonporous semiconductor layer located inside splitting the multilayer structure along the porous silicon layer but not along the diffusion region and removing the porous silicon layer …

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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

  • Filed November 14, 1997 and granted February 19, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 14, 2017.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 14, 2019.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 14, 1997
GrantedFebruary 19, 2002
Term endedNovember 14, 2017
Patent numberCA 2221245 C
Classification (IPC)H01L21/22 +2 more

Timeline

Timeline From CIPO dates

1998200020022004200620082010201220142016Application filedNov 14, 1997Patent grantedFeb 19, 2002Term endedNov 14, 2017

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