Plating process (2)

Desmear Detailed Process:

0. Drill Process: Drilling is performed to connect layers. Smear occurs within the holes on the base copper.

 

Sweller: Weakens the bond between smear and epoxy resin.

 

Epoxy Etching: Etches the epoxy resin, removing smear from the epoxy resin.

 

Neutralizing: Cleans the interface between layers to provide stability for electrical connections.

 

Swelling:

Uses high-temperature and high-alkaline chemicals to weaken the molecular bonds between smear and epoxy resin, converting polymer to monomer. Breaking intermolecular bonds reduces energy activation, making etching easier.

 

Epoxy Etching:

Utilizes permanganic acid to etch the epoxy resin, simultaneously removing the interface smear. Smear, softened by the sweller, is removed by NaMnO4. Typically controlled by time.

 

Main Reaction: Epoxy resin + NaMnO4 + OH- -> 2MnO2 + CO2 + H2O + NaOH

 

Neutralizing:

Removes byproducts converted to manganese dioxide after the reaction and performs pre-conditioning for effective chemical electroplating.

 

Main Reaction: MnO4-, MnO4(2-), MnO2 + Neutralizer -> Mn(2+) + H2O

 

Today, we have covered the first step in the electroplating process, the desmear process. In the next post, we will continue by discussing chemical electroplating and electroplating.