Improvement in the Reliability of AlGaInP-Based Light-Emitting Diode Package Using Optimal Silicone and Leadframe Structure
H.-Y. Kim1,2, J.W. Lee2, Y.M. Moon2, J.T. Oh2, H.-H. Jeong2, J.-O. Song1, T.-Y. Seong1, M. Kneissl3, and H. Amano4
Published in:
ECS J. Solid State Sci. Technol., vol. 9, no. 1, pp. 015014, doi:10.1149/2.0332001JSS (2020).
Abstract:
We investigated how the reliability of red light-emitting diode (LED) packages was affected by the types of silicones and package structures. The tensile strengths of different types of silicones varied from 3.2 to 8.1 MPa and their elongations were in the range of 40-150%. To characterize the output maintenance of packaged LEDs, the packages were kept under an 85°C/85% relative humidity (RH) condition for 72 h, which was then reflow-processed at 260°C three times. The output powers of the samples were degraded by 1.27-21.2% after the process, depending on the types of silicones. Only the sample LD-B experienced cracking. The effect of four different leadframe structures on the reliability of the sample LD-B was characterized. After the thermal treatments, the sample with 4 leads (circular window) suffered cracking. Simulations showed that unlike the others, the sample LD-B displayed additional stress concentrator at the centre of the silicone encapsulant. The spray-coating test revealed that moisture was permeated mainly through the Polyphthalamide (PPA)/silicone interfaces. These results show that use of silicone with high tensile strength, spray-coating, and optimized leadframe structure can be effective in achieving the high moisture reliability of red-LED packages.
1 Department of Materials Science and Engineering, Korea University, Seoul 02841, Korea
2 LED Division, LG Innotek Co., Ltd., Paju, Gyeonggi 10842, Korea
3 Technical University of Berlin, Institute of Festkorperphys, D-10623 Berlin and Leibniz Institute of Hochstfrequenztech, Ferdinand Braun Institute, D-12489 Berlin, Germany
4 Centre for Integrated Research of Future Electronics, and Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8601, Japan
Copyright © The Author(s) 2019. Published by ECS.
This is an open access article distributed under the terms of the Creative CommonsAttribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in anymedium, provided the original work is properly cited.
Full version in pdf-format.