Study on the Dynamic Behavior of Repetitive Drop Test for Electronic Component and the Reliability

Abstract

The purpose of this research is to investigate the dynamic behavior of repetitive drop test for electronic component and the effect of test conditions on the reliability. Considering reliability of mobile devices such as cellular phones, it is important to establish the drop impact reliability for solder joints. Many test methods have been investigated, but there are several unclear problems, such as dispersion of test result, failure mechanism and so on. In this paper, the authors proposed a repetitive drop test with simple equipments as to standardize the accelerated methods of drop impact reliability. And the authors classified roughly problems for standardization into two groups. One is the problem of repetitive drop test method. It contains collision angle between holder and ground, supporting condition of the specimen, and acceleration rate of repetitive drop test. The other is the mechanical problem of dynamic fracture. It contains interaction between holder and PCB (Printed Circuit Board), dynamic behavior of PCB, and failure modes of solder joints. For the former topics, when repetitive drop test is carried out, it is known that collision angle causes instable results of repetitive drop test. To solve this problem, a hemisphere was remodeled at the center of the holder’s bottom, and how the effect will be on the dynamic behavior of PCB was studied by series of dropping test. In addition, the acceleration test method of repetitive drop test was studied. For the latter topic, it is known that the dynamic behavior of PCB greatly affects failure of solder joints, and it is very important to understand what kind of deformation affects failure. The relation between holder and PCB was studied in view of the energy. In addition, the failure modes observed in repetitive drop test was examined by test results and analysis results.