Positive photoresists of the polyimide type
CA 2002149 A1 · Owner: Ciba-Geigy Ag · Inventors: Bartmann, Ekkehard; Sassmannshausen, Jorg; Schulz, Reinhard
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
K-17324/=/MER 21, Positive photoresists of the polyimide type Abstract of the Disclosure, The invention relates to positive working photoresists for producing relief structures of high-temperature resistant polyimide prepolymers, which photoresists can be developed in aqueous-alkaline medium and which contain in an organic, solvent, essentially at least a) one prepolymer which is convertible into a polyimide b) one radiation-sensitive quinonediazide compound and further optional components, said prepolymer being a completely esterified polyamic acid polymer.
Read the whole patent
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 3, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended November 3, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 3, 2011.
- 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.