Copper plating line process:
Electroless copper plating line is a process for printed circuit board manufacturing, often called sink-copper or PTH, which is a self-catalytic redox reactions. First treatment with activator agent, adsorbed on insulating substrate layer surface of active particles usually as metal palladium particles (palladium is a very expensive metal, the price is high and has been rising, to reduce cost now practical colloidal copper process is in the application), copper ions are first reduced on these active palladium metal particle, which these reduced metal copper nuclei itself has become a copper ion catalyst layer, so that copper reduction proceed on these new copper nuclei surfaces.
Electroless copper plating: traditional copper plating mostly as vertical lines, process are similar, the general process is:
Cleaning → Neutralization → Degreasing → Microetching → Pre-ditching → Activation → Chemical copper plating.
The main components are cathode and anode in copper plating line:
Cathode: giving rise to the starting & end a couple of stainless steel rod having a pair of electrical contact ring, copper brush is pressed against the copper ring in order to get good contact, connected to the negative pole of rectifiers. By retaining roller, the cathode cut off contact with plating solution.
Copper plating line anode: 2 titanium plate installed in plating bath, these two anode pieces connect with positive rectifies pole by electricity cable directly. Anode soaked in chemical plating solution.
Chemical copper plating line principle:
Electroless copper plating on the surface of the catalytic activity by the action of a reducing agent to precipitate the copper ions reduced:
Reduction (cathode) reactions: CuL2 + + 2e- → Cu + L
Oxide (anode) reaction: R → O + 2e-
Thus, with hypophosphite as a reducing agent for chemical copper plating main reaction is: 2H2PO2- + Cu2 + + 2OH- → Cu + 2H2PO3 + H2 ↑
In addition to the establishment of the thermodynamics, chemical reactions must also meet dynamics conditions. Like other chemical copper as the catalytic reaction thermal energy is required to cause a reaction, which is why only when the chemical bath plating deposition get speed plating under certain temperature. Theoretically copper plating speed to express by increasing the concentration of the reaction product of reactant concentrations and reduce the speed. In actual use, the electroless copper plating solution containing certain additives, its have too many factors to effect, the situation becomes too complicated. Thus, most of the electroless copper plating dynamics research is limited to the most basic component of the bath at the start.