Atomic Force Microscope-Based Meniscus-Confined Three-Dimensional Electrodeposition

The development of a 3D electrochemical deposition system, which combines meniscus-confined electrodeposition (MCED) with atomic force microscope (AFM) closed-loop control and has a submicron resolution, is described. Thanks to the high rigidity of the hollow borosilicate glass (or quartz) tip and quartz crystal tuning fork (QTF), combined with the QTF's high force sensitivity, the use of a solution-filled AFM tip in air is successful. The AFM control enables full automation and in situ growth control. Using this scheme, 3D printing of high-quality, fully dense, uniform and exceptionally smooth, freestanding straight and overhang pure polycrystalline copper pillars, with diameters ranging from 1.5 µm to 250 nm, and an aspect ratio > 100, is demonstrated. This process may be useful for manufacturing of high-frequency terahertz antennas, high-density interconnects, precision sensors, micro- and nano-electromechanical systems, batteries, and fuel cells, as well as for repair or modification of existing micro-sized or nano-sized features.