Reliability study on high density LED packaging with Chip On Board structures

In this paper an improved LED (Light emitting diode) packaging structure was proposed, which is based on COB (Chip On Board) technology. This research mainly analyzed the thermal reliability of a 4×4 square LED die array with COB technology during temperature load. Simple intuitive for observation, two specific red glue curing profiles were compared with different curing temperature, curing time, temperature rate, and room temperature holding time, and the influences of the temperature load to LED packaging were compared with and without consideration red glue curing before the subsequent thermal cycles loaded. Last the prediction of the Silicon substrate failure was carried on referring to the Weibull distribution. The light system consists of sixteen chips that each chip is 1.2W. Every die in the LED array can be regarded as working under the same condition, the heat distribution in each die is uniform. 3D finite element model of the LED packaging was modeled.