Gold electrodeposition is widely employed in microelectronics and connector manufacturing, where coating uniformity critically affects device reliability and performance. This study evaluates the effects of electrolyte pH, bath temperature, and gold concentration on deposition uniformity and efficiency in a cyanide-based bath. Electrodeposition was conducted at current densities of 0.2 and 50 A/dm 2 with a fixed charge of 5 C, and coatings were characterized using X-ray fluorescence, as well as Hull cell and Haring-Blum cell tests. Cathodic polarization results show that increasing pH shifts potentials negatively due to enhanced hydrogen evolution, whereas higher temperatures induce cathodic depolarization and shift potentials positively. The throwing power of 72.1%–85.9% decreased with increasing pH and temperature. Hull cell analysis indicates that coating thickness increases with pH, temperature, and gold concentration; however, optimal uniformity is achieved at lower pH (3.5–4.5), moderate temperatures (25°C–35°C), and gold concentration of 2 g/L. These conditions enable uniform coatings while reducing gold consumption. • Au coating was electroplated on Ni-precoated Cu substrate • The uniform gold plating thickness was varied by electrolyte pH, temperature and metal concentrations in solution • The polarization curves were shift with the change of electrolyte parameters • The uniformity of thickness was achieved by utilizing Hull-cell experiments
Do et al. (Fri,) studied this question.