Failure analysis of die-bonding interfaces between LED chip and heat sink

The die bonding technology played a key role during the heat dissipating process in the high power LED packaging. At present, many manufacturers were confused about which kind of bonding technology they should choose. In this study, the high power LED devices from Cree and Lumileds were employed to study their die-bonding technologies. For the tested Cree's products, the initial interface had few voids before aged, however, under the action of injection current, the voids would initiated and propagated along the bonding boundary between LED chip and heats sink. For the tested Rebel LEDs, the crack and delamination of bonding pads were observed at the LED chip side.