Effect of Materials Interfacial Strength and Environmental Conditions on Reliability of LED Packages

• Main Authors: You Lin Peng, 彭宥箖
• Other Authors: M. Y. Tsai
• Format: Others
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/00087585444624256296

碩士 === 長庚大學 === 機械工程學系 === 101 === The purpose of this research is to the material interfacial strength and the reliability of LED package. According to previous researches and literature, the oxidation and delamination of materials affect the reliability severely. This study is mainly divided into two parts: the first part is to study the bonding strength of silicone (with and with anti-precipitation powder) and other materials (leadframe and plastic materials). From the results of Peeling Test, the bonding strength of silicone with anti-precipitation powder lowers to 70% of the original. And the bonding strength between silicone and leadframe is 5~10 times higher than the bonding strength between silicone and plastic material. The second part is to study the oxidation of materials interface by long-life-time reliability test and thermal shock test. After life-time reliability test, some LED packages appear dark and delaminated. By the XPS (X-ray Photoelectron Spectroscopy) analysis, it is fund the dark surface is due to oxidation. Under 85℃ environment and powering for a long time, the packages with the silicone of high oxygen permeability have oxidation phenomenon, while there is no oxidation phenomenon under 85℃/85%RH environment, because the oxygen permeability is preventol by absorbing moisture. However, there is no oxidation phenomenon for package with the silicone of low oxygen permeability. In the thermal shock test, they are the same phenomena. To use the silicone of high oxygen permeability will cause materials oxidation in high temperature shock, but not in low temperature shock. So, we can infer that the high temperature and high oxygen permeability are the main cause to the oxidation phenomenon.