Au-Sn Solders Applied in Transient Liquid Phase Bonding: Microstructure and Mechanical Behavior

Abstract

Transient liquid phase bonding offers one option to generate a robust lead-free die attach with sound thermal and electrical conductivity in microelectronic packages. However, it remains a challenge to characterize the microstructure of the bonding layer because of its ultra-thin thickness and its nano-sized constituents. In this work, we characterized a Au-Sn soldering system of transient liquid phase bonding process in detail using various advanced techniques which successfully identified the nano-constituents and mapped their distribution in the sub-layers. On top of that, the mechanical behavior of the bonding layer has been investigated by micro-cantilever bending testing.

Keywords: Au-Sn solder, micro-cantilever testing, micro-bending, fracture toughness