This work systematically examined the development of a new plating bath for fine-patterned manganese electrochemical deposition on an organic substrate under various conditions. Hull cell tests, potentiodynamic scans, and galvanostatic experiments conducted with widely diverse pH and current densities revealed that CyDTA played a critical role as a pH buffer in the formation of fine-patterned manganese films. Optimized plating conditions enabled the formation of fine-patterned manganese electrochemical deposits of 10 μm squares with 20 μm pitch.
Using a sulfuric acid solution containing thiourea was investigated for selective and equivalent etching of copper in contact with dissimilar metals: Sn, Ni, Fe, and Zn. The copper electrode potential was dropped with increasing thiourea concentration. In contrast, the potentials of the other metals （Sn, Ni, Fe, Zn） exhibited upward trends with increasing thiourea concentration. Each metal, except for Zn, showed a potential crossing point with copper at a certain thiourea concentration depending on the metal. Copper was etched selectively at thiourea concentrations higher than the potential crossing point. Copper and the other metals were etched equivalently around the potential crossing point. The thiourea concentration of the potential crossing point was increased concomitantly with increasing metallic ion concentration. Results show that the etching rates of contacting copper and the other metal were controlled arbitrarily by adjusting the thiourea concentration. The thiourea concentration must be strictly controlled to establish a sustainable selective or equivalent etching system.