A structure design in HP-LED chip for higher reliability

As the fourth-generation lighting, LED attracts a lot of public attention with the advantages of high luminous efficiency, energy-efficiency, environment protection and long lifetime. Stress is one of the most important reasons in affecting high power LED (HP-LED) reliability and lifetime. The stress may be generated from heat, current or humidity, and has bad influence on LED reliability. In this paper, a new structure for HP-LED chip with a via was proposed to reduce the maximal thermal stress of LED chip. Firstly, the thermal stress and the temperature distributions of conventional HP-LED are simulated with the application of ANSYS software. The result shows that the highest temperature is on LED chip and the maximum thermal stress is at the four corners of LED chip. And then, the thermal stress distribution of the new chip structure was simulated as well, based on the whole model above with only changing the structure of the LED chip. Compared to the conventional HP-LED structure, the result suggests that the maximal thermal stress of new HP-LED structure is lower. Finally, the Synthesis analysis was finished to guide the LED structure design and improve the HP-LED reliability.