Plating process (10)

Major Components of Electroless Plating - Inorganic

 

CuSO4*5H2O: Source of Cu ions, increases conductivity of the plating solution along with sulfuric acid.

 

H2SO4: Improves electrical conductivity, enhances throwing power, and reduces plating thickness variations.

 

Cl-: Assists in inhibiting plating reduction along with the carrier. Aids in the reduction reaction from Cu2+ to Cu+ along with the brightener.

 

Major Components of Electroless Plating - Organic

 

Brightener: Basic intermediate conductor required for the reduction reaction of Cu ions. Works synergistically with the leveler to improve overall plating quality. Also, reduces plating particle size for a shiny surface.

 

Carrier: Transports or regulates the brightener, leveler, Cl-, etc., necessary for Cu reduction reaction. Also hinders the supply of Cu ions near the cathode (improves uniform deposition).

 

Leveler: Improves current distribution and hinders the supply of Cu ions. Due to the electrical characteristics, current density is higher on protruding parts. Thus, leveler adsorption is greater on high current density convex parts and lower on concave parts.

 

No Additives: Without additives, ions that interfere with copper deposition are absent, so they diffuse to active sites and create nuclei, resulting in coarse crystals, a dull appearance, and a fragile surface upon heat treatment.

 

With Additives: Additives adsorb to the cathode surface, hinder cathode surface reactions, and impede the nucleation of crystals. This leads to fine crystal formation, increased gloss, and the development of a uniformly deposited surface.

 

Today, we've learned about the electroless plating mechanism and additives.