Electrolytic Solution
Electroplating chemistry for circuit board manufacturing consists of copper sulfate and sulfuric acid combined with trace halides to deposit metallic copper onto board traces and within via holes. An acid copper sulfate bath provides the primary source of copper ions for electrolytic deposition in the fabrication of rigid printed boards. The reaction is driven by an external direct current source that forces metal ions to reduce at the cathode surface.
Anode dissolution replenishes the copper ions in solution to sustain the deposition process over hours of continuous operation.
Deposition Control
Organic additives regulate the plating rate across varying features to ensure uniform thickness. Without these compounds, the electrodeposition rate would be much higher on the surface of the board than inside narrow high aspect ratio holes, leading to incomplete plating or voiding. The bath chemistry must be carefully balanced to prevent uneven metal distribution.
Bath Maintenance
Periodic analysis of the chemical constituents maintains the performance of the plating system over extended production cycles. Testing is performed via cyclic voltammetric stripping to measure the concentration of active organic components. This analytical technique prevents the accumulation of breakdown products that would otherwise degrade the ductility of the plated copper.
