Stripping / Etching
The so-called step ‘Resist Stripping’ follows immediately after the electroplating process. The photoresist, which has been added, is chemically removed from the panel and leaves the copper on the panel. Electroplated tin covers the other surfaces.
In the ‘Etching’ process step, an alkaline etchant removes the copper that is exposed between the traces. This process structures the layout of the PCB. The electroplated tin functions as a protective coating. It is removed in the following tin stripping process.