Electrochemical printing: software reconfigurable electrochemical microfabrication

Abstract

Electrochemical printing (EcP) is a software reconfigurable tool and process for electrodeposition of multi-scale, multi-material objects from input drawings. The EcP system—comprising custom LabVIEW print driver software, hardware, electrolyte and a microjet print nozzle—creates complex patterns by locally electroplating individual metal and alloy dots as the microjet rasters over a substrate. The rastering of a microjet just a few microns above the substrate provides extraordinary convective mass transfer rates, allowing material growth rates that are routinely two orders of magnitude greater than in conventional plating. EcP has the flexibility to vary the print resolution and material composition during the patterning process via real time control of the microjet fly height, electrolyte flow rate and applied current. Microjet fly-height is used to vary the print resolution from 50 to 1000 dots per inch during the printing of a copper pattern. Simultaneous control of electrolyte flow rate and applied current through the microjet nozzle is used to achieve high plating efficiencies, well-formed dots and alloys of specific compositions for the copper and nickel–copper systems. It is also shown that commercially available noble metal plating baths can be used in the EcP tool, despite the unusually large current densities achievable and the complexity of commercial bath additives. Issues associated with making EcP a robust tool for 2D and 3D microfabrication are discussed.

Sono-electrodeposition transfer of micro-scale copper patterns on to A7 substrates using a mask-less method

“…A number of alternative techniques [9][10][11] employing direct-writing or mask-less methods have also been developed to electrodeposit micro-structures, and these have the advantage of reducing the costs and limitations associated with conventional lithography. However, while these approaches are capable of high resolution, they are serial fabrication methods and therefore less suitable for the volume production of micro-devices.…”

Bipolar Electrochemical Displacement: A New Phenomenon with Implications for Self‐Limiting Materials Patterning

“…We have recently made the first demonstration of locally controlled microscopic bipolar electrodeposition on electrically isolated, macroscopic conducting substrates using a scanning bipolar cell (SBC) . The SBC geometry induces a high local potential variation in the electrolyte, even when using electrolytes with conductivities similar to standard electrodeposition baths . The previous study's redox chemistry was the highly reversible copper system, where localized copper reduction occurred beneath the SBC tip and equal, but opposite, oxidation of the copper substrate occurred in the far‐field, effectively letting the scanning tip sculpt the surface by redistributing copper from the far‐field to the region beneath the SBC.…”

Electrocodeposition and Characterization of Ni-WC Composite Coating From Non − Aqueous Bath

“…Among the processes deployed in order to produce metal matrix composites, electrodeposition technique has proved itself to be a convenient method by producing smoother and harder surfaces, better bonding between particles and metal, easy control of the coating thickness, the ability to deposit metallic and composite coatings and suitability for automation. In the recent past [2,3] electrodeposition of composites attracted renewed attention, due its adoption by major companies for the processing of advanced microelectronic components.…”