Effects of additives on filling blind vias for HDI manufacture

Copper electrodeposition from chloride-containing and chloride-free copper plating solutions was investigated. Effects of carrier, brightener and leveler on the filling power of copper deposits in blind via were investigated by response surface design. Metallurgical microscopy was used to measure the filling power. Design-expert software was used to obtain and analysis the regression equation for the filling power as the response to organic additives. An extra experiment was completed to verify the optimized condition. The results showed that chloride-ion-containing plating solution exhibited a higher filling power, compared to the case without chloride ions. The optimum conditions of each additive were obtained as the concentrations of brightener, leveler and carrier at 0.92 mL/L, 12.7 mL/L and 12.7 mL/L, respectively. The filling power of copper deposits was high at the optimum condition. The filling power of copper deposits for blind via was 97.38%, indicating less difference from that of the model value at 97.45%.