Thermal and Hygro Effect on delamination in LED package
Reliability problem is becoming a bottleneck of LED application in different fields.In previous studies many factors,such as thermal,moisture and electric,will lead to LED failure are investigated.Delamination is one of failures in light emitting diode during operation.In order to better understand the process of this failure experiment results and modeling results were compared.First of all the LEDs are tested at different temperatures and moistures and then examined at SAM.The results showed the delamination was occurred at the interface between die and die attach and with the temperature and moisture increase,the area of delamination increases.Secondly the three-dimensional finite element method was established to simulate the process of tests and to find the maximum stress in products.Meanwhile,for obtaining the accurate stress value the sub-model technique was used.The maximum stress existed at the surface of die attach when the test temperature are 25℃ and 85℃However,when the test condition are 85 /℃ 25% RH and 85℃/85% RH the modeling results showed the maximum stress existed at the interface between copper and epoxy.Finally,for understanding difference between experiment and modeling result.the cohesive zone method was used to simulate delamination in LEDs package at different experimental ambient.The modeling result showed the different interfaces have different adhesion strengths and the higher temperature and higher moisture have lower adhesion strength and delamination more obvious.
Bingbing Zhang Daoguo Yang
Guilin University of Electronics Technology No.1 Jinji Road,Guilin,China
国内会议
北京
英文
38-39
2013-11-10（万方平台首次上网日期，不代表论文的发表时间）