Development of an Accelerated Life Test Method Using the Conversion of Thermal Shock Stress to Mechanical Stress

In general, thermal-shock-induced accelerated life testing needs a considerable amount of time because of the slow response of thermal properties. However, the shortened lifecycle of electronic components requires an increasingly short reliability assessment time. To achieve this objective, a method for converting the thermal-stress-induced fatigue into the mechanical-stress-induced fatigue was developed by identifying a mathematical relation between the thermal stress and the mechanical stress. In order to prove the methodology for actual application, we have presented the thermal stress distribution data under field conditions for a miniature cylindrical inductor and a method to accurately simulate them using the artificially produced mechanical stress. The thermal stress distribution was predicted by means of the finite element method and the conditions capable of exerting a mechanical stress with a similar stress distribution were investigated. The accelerated life test model predicted a maximum acceleration factor of 3,582,000.This research was supported by the Reliability Industry Spreading Program through the Korea Institute for Advancement of Technology (KIAT) funded by the Ministry of Trade, Industry and Energy (2014N0001042), Republic of Korea