Meniscus-confined three-dimensional electrodeposition for direct writing of wire bonds

Continued progress in the electronics industry depends on downsizing, to a few micrometers, the wire bonds required for wiring integrated chips into circuit boards. We developed an electrodeposition method that exploits the thermodynamic stability of a microscale or nanoscale liquid meniscus to "write" pure copper and platinum three-dimensional structures of designed shapes and sizes in an ambient air environment. We demonstrated an automated wire-bonding process that enabled wire diameters of less than 1 micrometer and bond sizes of less than 3 micrometers, with a breakdown current density of more than 10¹¹ amperes per square meter for the wire bonds. The technology was used to fabricate high-density and high-quality interconnects, as well as complex three-dimensional microscale and even nanoscale metallic structures.