Determination of Thermal Fatigue Delamination of Die Attach Materials for High-Brightness LEDs

The thermal fatigue delamination interface of die attach materials in high-brightness light-emitting diodes (HB LEDs) is determined using a noninvasive approach. Failure analysis of HB LEDs containing Au80Sn20 eutectic alloy and silver paste as die attach materials is performed by monitoring the changes in the partial thermal resistances in differential structure function curves of the HB LEDs through power cycling experiments. The results suggest that delamination of the Au80Sn20 eutectic and silver paste materials occurs at the chip-to-die attach interface and die attach-to-heat sink interface, respectively, which is consistent with cross-sectional scanning electron microscope analysis.