Effect of electro-thermal diffusion induced deterioration on the failure mechanism of Pd-Au-coated Cu wires

Abstract

This study investigates the deterioration mechanisms of commercial Palladium-Gold-coated Copper wires during the packaging process due to electrification. We conducted long-term electrification tests using CPA wires and copper-plated silicon pads to simulate electro-thermal effects under operational conditions. The primary cause of CPA wire deterioration was found to be Joule heating resulting from electrification. The actual operating temperatures were verified through electro-thermal equations and electrifying-tensile tests. Additionally, vacuum heat treatment experiments were performed to simulate heat generation in low-oxygen environments. Analysis showed Pd diffusion depth of approximately 5 microns, indicating that under low-oxygen conditions, copper and oxygen tend to form cubic copper(I) oxide. These findings provide critical insights for electronic packaging industries regarding design, material selection, thermal management, and reliability enhancement of wires. This research not only highlights potential issues with CPA wires in electronic packaging applications but also proposes solutions, thereby advancing electronic packaging technologies. These results are significant for improving packaging performance and extending the lifespan of electronic products.