Enhancement mechanism of megasonic field on bubble removal in nickel micro electroforming

In order to promote the bubble removal in the fabrication process of micro structure and enhance nickel micro electroforming, megasonic field was introduced in this paper. Electrochemical measurement was used to analyze the effects of megasonic on micro electroforming, including tests on curves of cycle voltammetry, linear sweep voltammetry, Tafel and electrochemical impedance spectroscopy. Enhancement mechanism of megasonic field on bubble removal in nickel micro electroforming was revealed and micro structures with different dimensions were fabricated. Results of electrochemical measurement demonstrated that megasonic filed not only can promote the sufficient contact between substrate and electroforming solution, but also can decrease solution resistance and increase current. Besides, megasonic field can promote nickel deposition and weaken hydrogen evolution, improving the current conversion efficiency. Fabrication results verified that megasonic field is beneficial to promote bubble removal from the surface of electroforming area. Less surface defects, higher processing efficiency and higher success rate of micro structures fabrication can be accomplished under 6 W cm⁻² megasonic field. This study may provide novel idea and method on fabrication of micro-nano structure.