Conductivity Enhancement of Aerosol Jet Printed Components By Electrodeposition

Abstract

Additive manufacturing (AM) is an attractive technique in the production of electronic components at lower cost compared to traditional circuit fabrication techniques. Aerosol jet printing (AJP), a direct write technique (Figure 1(a)), uses an atomized mist of gas directed through a nozzle to achieve high resolution (< 10 μm) linewidth prints.[1] A wide variety of inks can be printed including conducting, magnetic, and insulating materials. The standoff distance of 1-5 mm allows for both planar and conformal printing with the aerosol jet. However, the films produced by aerosol jet printing are less conductive than bulk films due to the necessity to sinter nanoparticle inks. Building thick layers to achieve the necessary conductivity is possible, but it is both time consuming and reduces the achievable resolution of the printed part. An alternative approach is to use the aerosol jet printed structure as a seed layer for the deposition of a high conductivity film by electrodeposition.Aerosol jet printed components were made by printing 20 vol% UTDots Ag40X nanoparticle ink in 60 vol% xylenes and 20 vol% terpineol. Samples were modified by electrodeposition in a Microfab SC Cu bath (17 g/L Cu2+) with a Cu anode. Plating was performed in a 2-electrode configuration. Voltages between -0.4 and -0.5V were applied to the cell. Components modified included a transformer coil (Figure 1(b)) printed on a cylindrical ceramic bobbin. Here, modification of a 1.8 m long conductive coil reduced the resistance from 1.4 kΩ to 10 Ω. Similarly, Cu deposited on Ag traces over a 500 μm step decreased the resistance from 20-400 Ω to < 1 Ω. This technique represents a novel method to achieve both the high conductivity afforded by electrodeposition and the high resolution, low cost patterning of aerosol jet printing.