How to stabilize dilute sulfuric-peroxide based solution in presence of dissolved copper?
I work in a PCB fab, traditionally, we use dilute sulfuric-peroxysulfate based microetch machine conveyor (proccess used to clean circuit copper traces by uniform removal of 0.5u-1u copper), it's quite stable but it leaves heavy sulfate residues and oxidizes copper faster after rinse and drying
Other day, I tried making a dilute sulfuric-peroxide based microetch and its performance and finish quality was insanely good except peroxide based bath doesn't last very long in presence of copper ions, what can I do to stabilize dilute peroxide sulfuric based microetch bath in presence of metal catalyst, so far ive tried phosphoric acid, but only remained stable for a day
Basically, compared to persulfate, peroxide microetch gives higher quality but is very unstable and short lived, so what stabilizers would you recommend
Basically, I need to mantain a stable ORP for a longer period of time without oxidizer rapidly consuming itself