Direct bonding of copper to aluminum nitride

Direct bonding (DB) of copper to aluminum nitride was studied. The process parameters of DB were optimized based on time, temperature and thickness of the Cu-foil for Cu-Al2O3 system in an N2 atmosphere containing 500 ppm O2 in a temperature range of 1065 to 1075 °C. These conditions were then applied to the Cu-AlN system. Wettability of AlN by Cu was studied and improved through oxidation of AlN and modification of Cu by adding 1 at.% O2. The interface of AlN and Cu containing O2 was then simulated using powder mixtures. The oxidation of AlN was found to be the driving force for improving the wettability of the AlN by copper. The activation energy for oxidation of AlN was found to be 94 kJ mol−1. It was demonstrated that direct bonding of Cu to AlN can be performed without any intermediate layer. The average peel strength of AlN-Cu, Al2O3-Cu and AlN-Al2O3-Cu systems were 42, 49 and 14.7 MPa, respectively.