Positive type photoresist composition
CA 1255952 A · Owner: Sumitomo Chemical Co. Ltd. · Inventors: Hiroaki, Osamu; Yasui, Seimei; Furuta, Akihiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A positive type photoresist composition comprising a novolak resin and a quinonediazide compound the novolak resin being one which is obtained by the addition condensation reaction of a phenol and formaldehyde which is performed in one stage by using as a catalyst an organic acid salt of a divalent metal which is more electropositive than hydrogen, or in two stages by using an acid catalyst in the subsequent stage the, phenol being at least one compound represented by the formula wherein R is hydrogen or an alkyl group of carbon number 1 to 4, the compound being such that the average carbon number in the substituent per one phenol nucleus is 0.5 to 1.5 and the ones with the substituent at …
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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 20, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 20, 2006.
- 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.