Alkaline-containing photoresist stripping compositions producing reduced metal corrosion with cross-linked or hardened resist resins
CA 2106750 C · Owner: Avantor Performance Materials, Inc. · Inventors: Schwartzkopf, George
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Addition of non-nitrogen containing weak acids to amine-containing alkaline strippers for photoresists produce stripper compositions able to strip highly cross-linked or hardened photoresist films without producing any substantial metal corrosion. Weak acids useful in the stripping compositions include those having a pK in aqueous solution of 2.0 or higher and an equivalent weight of less than about 140 and are employed in an amount to neutralize from about 19% to about 75% of the amine present in the stripper composition.
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 September 22, 1993 and granted March 30, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 22, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 22, 2015.
- 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.