Bonding Characteristics of Solder and Sinter Joints on Active-Metal-Brazing Substrates with Nano Sputtered Ag-Cu-Ti Brazing Filler Metal

Abstract

In this study, to improve the bonding interfacial characteristics of active metal brazing (AMB) substrates, a Ag-Cu-Ti brazing filler metal (BFM) layer was formed on aluminum nitride (AlN) and silicon nitride (Si₃N₄) ceramics by nano sputtering. The AMB substrates were manufactured by brazing bonding. The measured peel strengths of the bonding interfaces of the AlN and Si₃N₄ ceramics were 2.35 kgf/mm and 4.26 kgf/mm, respectively. Fracture surface analysis revealed AlN crack initiation at the ceramic/BFM interface, which progressed into the ceramic interior. Silicon carbide (SiC) devices for a power module were bonded on the AMB substrates by Sn-3.0Ag-0.5Cu soldering and Ag sintering bonding. To compare the deterioration characteristics of the joint interfaces, a thermal shock test was conducted. Microstructural analysis after the thermal shock test showed that no defects occurred at the Si₃N₄/BFM interface, whereas delamination occurred at the AlN/BFM interface. Summarizing, in this study, the characteristics of AMB interfaces coated with a Ag-Cu-Ti BFM using the sputtering process were identified and the suitability of a SiC-based power module package was confirmed.