Material Deposition
Electrochemical coating techniques apply a uniform metallic layer to conductive surfaces immersed in an electrolyte bath under the influence of an external electrical current. The process, referred to as electrodeposition, builds the copper paths and via connections that form the electrical backbone of a printed circuit board. Ions migrate toward the cathodic board surface, where they receive electrons and reduce to solid metal.
The resulting layer provides the necessary conductivity to handle designed circuit currents. Plated through-holes rely on this continuous metal growth to link different board layers.
Process Parameter
Precise control of chemical concentration and current density governs the quality of the plated metal. Technicians monitor the bath temperature, organic additives, and agitation levels to prevent irregular grain growth or burning at high-current areas. Adding proprietary organic suppressors and levelers ensures that copper grows preferentially in narrow blind vias rather than on the flat surface.
Maintaining a stable current flow prevents variations that lead to thin plating and subsequent circuit failures.
Thickness Uniformity
Inadequate control over the metal deposition leads to uneven copper thickness across the board area. Electrodeposition must be carefully calibrated to avoid over-plating near the panel edges while leaving the center under-plated. Regular cross-sectional measurements or X-ray fluorescence tests ensure the thickness meets IPC specifications.
