Low-temperature solid state bonding of Sn and nickel micro cones for micro interconnection

Abstract

This paper reports a low-temperature solid state bonding method for potential use in advanced electronic packaging, especially in 3D integration applications. Electrodeposited Ni micro cones with an Au anti-oxidation layer were fabricated and utilized to bond with Sn-capped Cu bumps with the help of appropriate temperature and pressure. Bonding joints were shear tested to evaluate the joint strength of samples bonded at each pressure, with results comparable to reflow soldering. Microscopic observation showed sufficient insertion between Sn and cone-structured Ni, as well as atomic scale bonding between two metals. © 2012 The Electrochemical Society. All rights reserved.