Acid Degreasing
- Remove oxides on the copper surface of the circuit, residual glue, and ink residue film.
- Ensure bonding force between primary copper and patterned copper or nickel electroplating.
- Alkaline degreaser damages graphic circuits as the graphic ink is not alkali-resistant.
- Only acid degreaser can be used before graphic plating.
- Degreaser concentration should be around 10% with a time of 6 minutes.
- Supplementary addition should be 0.5-0.8L per 100 square meters.
Micro-Etching
- Clean and roughen the copper surface for bonding between patterned copper electroplating and primary copper.
- Sodium persulfate is often used with a concentration of around 60 g/L and a time of about 20 seconds.
- Control copper content below 20 g/L.
Pickling
- Remove oxide and activate board surface using C.P grade sulfuric acid.
- Acid leaching time should not be too long to prevent surface oxidation.
- Replace acid solution if turbid or if copper content is too high.
