Contact Resistance of 3D-Printed Interconnects to Thin-Film Metals for Advanced Packaging

High resolution 3D-printing of conductive inks has shown promise in enabling rapid prototyping for package scale interconnects and devices. If additive manufacturing becomes broadly adopted for package and chip-scale prototyping, it is critical to investigate contact resistance between printed materials and IC bond pad materials. In this work, contact resistance between direct-write printed silver interconnects and common IC contact materials (aluminum copper, gold) was measured across a range of ink thermal cure conditions. While contact resistance to gold and copper pads was largely dominated by sheet resistance and improved with increased cure time and temperature, contact resistance to aluminum pads was an order of magnitude larger, and increased with increasing cure time and temperature.