The effect of acid on fast through-hole filling by Cu electroplating

Through-holes (TH) filling of printed circuit board (PCB) by copper electroplating using single organic additive was carried out. The inhibition of the organic additive was sensitive to acid. We chose different kind of organic acids with different concentrations as supporting electrolytes to achieve TH copper filling, which was called butterfly technology (BFT). To reduce plating time, high current density was necessary but it had to combine with raising the concentration of chloride ions and force convection. These combinations can significantly improve the filling performance of the copper plating solution. All of the results of electroplating were observed by optical microscope (OM).