Selective deposition on electrodes of chip component by electroless plating method

摘要

The selective electroless deposition on metallic electrodes of a micro-passive-chip component was investigated. We performed three pretreatments: (a) alkaline degreasing, (b) acid activation, and (c) catalytic activation by the double alternate-dipping method consisting of two steps, i.e., sensitization (SnCl_2 and activation (PdCl_2). Catalytic conditions such as the concentration of PdCl_2, activation time, and number of activation times were optimized to achieve the selectivity of electroless deposition. The mechanism of the selectivity of electroless deposition was investigated by X-ray photoelectron spectroscopy measurements. Tetravalent Sn and metallic Pd are observed on the inner electrode of the sample. On the other hand, metallic Sn and tetravalent Pd are mainly observed in certain areas except the inner electrode areas. These results indicate that the sensitization is performed well in the inner electrode region because Pd must be in a metallic state to validate its catalytic activity.