The Degradation Mechanisms of Underfills Subjected to High Temperature Long Term Aging

Abstract

Much of automotive electronics used to support power systems and enable safety systems resides underhood. Underhood electronics may be subjected to sustained temperatures of 125-150°C for prolonged periods during operation. Majority of the available plastic encapsulated electronic components are designed for operation at 55-100°C and lower lifetimes about 3-5 years. There is dearth of commercially available components designed to operate reliably above 150°C for extended periods-of-time. The insufficient information on materials, interconnects, and packaging systems capable of surviving high temperatures for long periods (>100,000 hours), which are compatible with and protect the electronics. In this paper, 4 different types of underfills has been cured and ageing. Mechanical tests have been performed for 4 types of underfills. Uniaxial tensile tests are conducted to study the elastic modulus, ultimate tensile strength and percentage elongation of 4 types of underfills. SEM and EDX are applied to study the microstructure behaviors of 4 types of underfills. The raw data on packaging material is collected. The experimental results are compared before and after aging tests, including pristine, 30 days, 60 days and 90days. The research focuses on microstructure-property-processing-performance relationships. Reliability physics of high temperature degradation of packaging material is studied.