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Expired European patentEurope

Method for controlled doping trench sidewalls in a semiconductor body

EP 0174997 B1 · Applicant: AT&T Corp.

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Overview

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Filed March 25, 1985 and granted August 3, 1988. A European patent lasts at most 20 years from filing, so its term ended March 25, 2005.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by September 25, 2010.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledMarch 25, 1985
PublishedMarch 26, 1986
GrantedAugust 3, 1988
Term endedMarch 25, 2005
Application numberEP 85901826
Classification (CPC)H10P32/1414 +2 more

Timeline

Timeline From EPO dates

1986198819901992199419961998200020022004Application filedMarch 25, 1985PublishedMarch 26, 1986Patent grantedAug 3, 1988Term endedMarch 25, 2005

Sources & verification

Official EPO records

Full published documentClaims, description and drawings as a PDF.EPOEuropean Patent RegisterProcedure, status, file inspection and legal events.EPOLinked open EP data recordThe bibliographic record this page is built from.EPO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comEspacenetNational family members and their legal status.European Patent Office

Everything on this page comes from the EPO record linked above. EPO data used under CC BY 4.0.