BME-Assisted Fabrication of Porous Copper Films with Adjustable Porosity and Ligament Width for Microelectronic Interconnects

Abstract

Monolithic porous Cu films are synthesized through the use of bicontinuous microemulsion (BME) to serve as a flexible template. The BME system is made up of a series of interconnected linked water and hydrocarbon phases. This one-of-a-kind structure enables precision Cu electrodeposition only in the aqueous phase, avoiding undesirable electrodeposition in the oil phase. We can fine-tune the porosity and ligament width of the resultant copper film by altering the oil phase proportion in the soft template. This Sn-plated porous Cu is capable of both low-temperature reflow and high-temperature service. The flexible template approach shows great potential for creating porous Cu with changeable porosity, allowing for more control over compositions. This approach has potential applications in advanced packaging technologies.