Soldering of Ti+Cu Dual Metallized AlN to Copper Substrate

Bonding of Aluminum Nitride to Copper using Surface Modification Technique (Report 1)

Abstract

Soldering of surface-modified AIN to copper was investigated using Sn-38 mass%Pb solder. AlN substrate was dually metallized by Ti and Cu using ion plating technique as follows ; the 10μm thick Ti film was first plated on the AIN substrate, heat-treated in vacuum on various conditions and then the 5-10μm thick Cu film was plated on the heat-treated Ti film again. The thermal stress and heat conduction analyses suggested that the soldered joints could possess the superior properties when the thickness of soldering layer was kept less than 0.4 mm. Defects such as micro voids and cracks were occurred in Ti film after heat treatment, and the fraction of defects increased with increasing the treating temperature and time. The tensile strength of Ti+Cu dual metallized AlN to copper joint was approx. 20 MPa, and slightly decreased as the treating time of Ti film was increased. The Ti+Cu dual metallized AIN to copper soldered joint indicated the superior reliability for thermal fatigue and heat conduction.