Thermal transient characteristics of flip chip high power light emitting diodes

The die-attached quality and the thermal transient characteristics of high power flip chip light emitting diodes (LEDs) are investigated using thermal transient tester. Various die-attached materials were utilized to compare the difference in their thermal resistances and long term performance. By applying accelerated aging stress, the deterioration rates at the die-attached layers were obtained. Numerical simulation provided further understanding of LED device temperature distribution and also revealed that the thermal variance at the die-attached interface can be recognized within only few milliseconds for the flip chip structure. The effects of bump arrangement and material were analyzed to achieve high temperature uniformity and low thermal resistance for high power LEDs.