부산대학교 도서관

A modern development process of lifetime prediction for reliable electronics uses numerically prepared failure data from accelerated thermal-cycling aging experiments. In this type of experiment, soldered assemblies are subjected to a temperature cycling load and damaged by low cycle fatigue procedure. The solder joints of this LGA-like assembly are stressed by an increased temperature range to accelerate the degradation of the solder alloy material and initiates the change of microstructure and crack propagation. Creep mechanisms in SAC-based solder alloys are activated at the temperature ranges of 150 °C to -40 °C. Tests without accelerated conditions take too much experimental time and costs until reaching mean time to failure. On the other hand, the level of acceleration due to an increased temperature range is limited by the package materials and damage mechanisms. The major challenge is to transfer these accelerated failure data to a lifetime estimation under field conditions, which operates in reduced temperature range. Electronic designers require the acceleration factors or lifetime estimation data to adapt suited, reliable electronic to field condition of electronics in services.