Brazing of AlN to Copper using Low Expansivity Interlayer

Study on Bonding of Aluminum Nitride to Metals (Report 3)

Abstract

The influence of the low expansivity interlayer on the cracking susceptibility and properties of AIN -copper joints brazed with Ag-Cu-Ti filler metal was examined. The thermal stress and heat conduction numerical analyses suggest that not only crack-free joints but also the superior thermal conductive joints can be produced by employing tungsten or molybdenum interlayer for AIN to copper joining. The cracking of AIN-OFC joints can be prevented by increasing the tungsten and molybdenum interlayer thicknesses above 0.8 mm and 2.0 mm, respectively. The tensile strength of AIN-OFC joints brazed at 1078 K for 120 s with 1.0 mm thick tungsten interlayer is approx. 50 MPa. AIN-W-OFC joints using Ag-Cu-Ti filler metal indicate the superior reliability for thermal fatigue and heat conduction.