Packaging technology for high power blue-green LEDs

Akhter, Mahbub; Maaskant, Pleun P.; Casey, Declan P.; Rohan, James F.; Cordero, Nicolas; Corbett, Brian M.

Packaging technology for high power blue-green LEDs

Files

9689.pdf(635.08 KB)

Accepted version

Date

2005-04

Authors

Akhter, Mahbub

Maaskant, Pleun P.

Casey, Declan P.

Rohan, James F.

Cordero, Nicolas

Corbett, Brian M.

Publisher

Society of Photo-optical Instrumentation Engineers (SPIE)

Published Version

10.1117/12.605829

Abstract

High brightness LEDs (HBLEDs) have been fabricated on GaN semiconductor material grown on sapphire substrate. These devices provide an optical output power in excess of 50 mW at a driving current of 1 amp. For this hi-h current application, large size (1.8 mm X 0.6 mm) GaN LEDs are flip-chip mounted onto a heat sink to provide a low thermal resistance path from the junction to the ambient. For the flip-chip mounting, a Au/Sn/Au solder and a Au/Au thermal compression bonding process have been optimized. The bond strength of the Au/Sn solder joints and the Au-Au bonds is measured through shear testing. Good bond strength results of 224 g/f for the Au/Sn/Au solder and 288 g/f for the solid Au bonds have been achieved. The thermal modeling of the assembly is done with a finite element analysis and the optimum design has been adopted for this high current application. At present these assemblies are under lifetime test and so far nearly 6000 hours of continuous operation has been achieved.

Keywords

HBLED , Flip-chip mounting , Solder , Thermal compression bonding

Citation

Akhter, M., Maaskant, P., Casey, D., Rohan, J., Cordero, N. and Corbett, B. (2005) 'Packaging technology for high power blue-green LEDs', Proceedings of SPIE, 5825, Opto-Ireland 2005: Optoelectronics, Photonic Devices, and Optical Networks, Dublin, Ireland, 4-6 April. doi:10.1117/12.605829