THE EFFECT OF PACKAGING MATERIAL AND PROCESS ON DEVICE PERFORMANCE OF LIGHT EMITTING DIODE

摘要

The needs for light emitting device with high flux under high power operation have been increased in wide range of applications from automobile to small consumer products. The acquisition of a good thermal management in LED under high flux operations is critical, which can suppress a thermal degradation and increase a lifetime of devices. Therefore, as the power intake of light emitting device increases, the packaging and assembly process becomes more and more important in thermal behavior of the development of light emitting device. LED with adopting the eutectic solder system of Sn-Ag in die-attach process has been investigated in this work. Thermal resistance of device with silver paste was 8.2 K/W, and 6.5 K/W with solder in the current study, which indicates the decrease of about 2K/W in a thermal resistance was found in the LED processed with eutectic solder in comparison to a conventional LED with Ag paste dieattach. It was observed that the LED applied with dieattach of the Sn-Ag solder showed a drastic reduction in optical power depreciation under 85oC, 350 mA operation compared to that of a conventional LED with Ag paste as well. As a result, the improvement in a thermal performance and a lifetime has been proved in this study.