서브 마이크론급 구리 입자의 은도금 공정에 따른 내산화성 강화 연구

To fabricate a copper (Cu)-based fine conductive filler having antioxidation property, submicron silver (Ag)- coated Cu particles were fabricated and their antioxidation property was evaluated. After synthesizing the Cu particles of 0.705 μm in average diameter by a wet-reduction process, Ag-coated Cu particles were fabricated by successive Ag plating using ethylene grycol solvent. Main process parameters in the Ag plating were the concentration of reductant (ascorbic acid), the injection rate of Ag precursor solution, and the stirring rate in mixed solution. Thus, Ag plating characteristics and the formation of separate fine pure Ag phase were observed with different combinations of process parameters. As a result, formation of the separate pure Ag phase and aggregation between Ag-coated Cu particles could be suppressed by optimization of the process parameters. The Ag-coated Cu particles which were fabricated using optimal conditions showed slight aggregation, but excellent antioxidation property. For example, the particles indicated the weight gain not exceeding 0.1% until 225oC when they were heated in air at the rate of 10oC/min and no weight gain until 75 min when they were heated in air at 150oC.