Method of removing negative acting photoresists
View Patent ↗Polymerized negative acting photoresists are removed from substrates at relatively low temperatures and fast stripping times using aqueous based alkaline solutions.
1. A method comprising:
a) providing a substrate comprising polymerized negative acting photoresist; and
b) contacting the substrate comprising the polymerized negative acting photoresist with an aqueous alkaline solution consisting of ammonium hydroxide at a concentration of 0.1 g/L to 15 g/l, one or more alkanolamines at a concentration of 0.5 g/l to 100 g/L, one or more quaternary ammonium hydroxides and one or more anticorrosion agents and water to remove the polymerized negative acting photoresist from the substrate.
2. The method of claim 1 , wherein the polymerized negative acting photoresist is removed from the substrate at temperatures of 15° C. or higher.
3. The method of claim 2 , wherein the polymerized negative acting photoresist is removed from the substrate at temperatures of 30° C. to 50° C.
4. The method of claim 1 , wherein the one or more anticorrosion agents are chosen from aromatic hydroxyl compounds and triazole compounds.
5. The method of claim 1 , wherein the polymerized negative acting photoresist has a thickness of 10 μm or greater.
6. The method of claim 5 , wherein the polymerized negative acting photoresist is an inner layer polymerized photoresist and has a thickness of 30 μm to 40 μm.
7. The method of claim 5 , wherein the substrate is a printed circuit board.
8. The method of claim 7 , wherein the polymerized negative acting photoresist is an outer layer and has a thickness of 50 μm to 100 μm.