Multi-layer PC boards Fabricated using Aerosol-jet Printing

Abstract

Additive manufacturing methods hold several advantages over standard semiconductor fabrication techniques such as the reduction of hazardous waste, the reduction of fabrication steps and the elimination of mask sets. For prototyping, low volume manufacturing and custom parts, additive manufacturing has the potential to dramatically reduce both the time and cost of fabrication. As a demonstration of the capabilities of additive manufacturing, a ‘2-layer’ power supply circuit board was fabricated using aerosol-jet printing. Silver nanoparticle ink was used to print the conducting layers and polyimide was used to print the dielectric layer. Each layer was printed separately and sintered/cured for at least 90 minutes up to a temperature of 255 °C. For an initial proof of concept, a power supply circuit was selected, providing three different voltage outputs. In order to supply the necessary current while minimizing topology, the metal traces were designed to be as wide as possible while staying within a 16 × 20 mm footprint. Additionally, an “inverse via” scheme was utilized in which the dielectric layer was printed only where layer-to-layer isolation was needed. This minimized the amount of material used and eliminated the need to include standard vias into the design. Once printed, a 2-layer circuit board was populated by using standard pick-and-place techniques and a conductive adhesive to attach components in place. Built up boards were tested for functionality at room temperature, thermally cycled from 10 to 80 °C for 63 cycles and subjected to high temperature operational life testing at 70 °C for 96 hours. Design criteria, fabrication methods and test results will be presented in detail.