Tapering sidewalls of via holes
CA 2064922 C · Owner: Nortel Networks Corporation · Inventors: Jolly, Gurvinder; Yung, Bud K.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of tapering side walls of via holes and a tapered via hole structure for an integrated circuit is provided. Via holes having steep sidewalls are provided in an insulating layer overlying a conductive layer on a substrate, with an underlying conductive layer exposed at a bottom of each via hole. A protective layer is provided over the conductive layer in each via hole and over the, sidewalls. The via holes are then tapered by argon sputter etching to remove the protective layer and part of the insulating layer from the sidewall and around the peripheral edge of each via hole, thereby smoothly tapering the sidewall and providing a via hole increasing continuously in diameter from the …
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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 April 2, 1992 and granted November 24, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 2, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 2, 2014.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.