Application of Selective Electrodeposition of Copper Arrays Based on Bicontinuous Microemulsion in Power Device Packaging

Next-generation devices stand out due to their superior characteristics, thereby necessitating high-performance packaging materials to endure severe operational conditions. Incorporating 3D porous frameworks to expand the reaction interface can further accelerate the reaction kinetics, making transient liquid-phase bonding an ideal option for the interconnection process. This study centers on synthesizing monolithic porous Cu films through selective electrodeposition, employing a bicontinuous microemulsion (BME) as a dynamic soft template. The BME phase is defined by interlinked 3D networks of aqueous and oil phases, separated by surfactants and cosurfactants. This unique structure enables highly selective Cu electrodeposition, ensuring deposition occurs solely within the aqueous domains while preventing unwanted reactions in the oil phase. By modifying the water-to-oil phase ratio in the BME, the porosity of the monolithic Cu film can be accurately regulated. The tin-coated porous Cu films prepared via this selective electrodeposition method exhibit notably low-temperature reflow properties while maintaining high service temperatures. Utilizing the BME soft template in selective electrodeposition presents a promising strategy for fabricating monolithic Cu films with tunable porosity, offering considerable versatility in controlling interconnection compositions and performance.