Prediction of Bending Reliability of BGA Solder Joints on Flezible Printed Circuit (FPC)
In this paper, the mechanical performance of solder joints of BGA mounted on flexible printed circuit (FPC) was studied using finite element method (FEM). To optimize the electric components layout during the design, it is necessary to predict the bending reliability of components on FPC. Traditionally, 3-point or 4-point bending are common used to study if the substrate is rigid. In order to simulate the free bending condition with soft substrate, a new bending method is taken. Thats to fix the FPC at one side and move the other side to bend the FPC. Based on this novel model, the length of the FPC, the height and diameter of the solder joints are respectively taken as the optimized variables. With the variable change, there are many different cases. For one general case, the bending process is divided into two steps. At first, to rotate the FPC about 180° at one side and make the two fixtures parallel; then move the fixture to control the bending. It is found that the stress of the solder joints in first step linearly proportioned increase with the bending. While in the second step, the stress reaches the peak and declines gradually with the two ends of the FPC get closer. Simulation results indicate that by using the longer FPC can improve the reliability significantly. Normally, reliability can be also improved by increasing the height and diameter of the solder joints. While in the translating-induced bending, increasing the diameter will worsen the solder reliability unless the diameter is larger than 0.3mm.
Jianlin Huang Quayle Chen Leon Xu G. Q. Zhang
Guilin University of Electronic Technology,No. 1 Jinji Road, Qixing Area, Guilin, Guangxi, China, 54 Nokia Research Center (Beijing)No. 5 Dong Huan Zhong Lu, BDA, Beijing, China 100176 Strategy and Business Development of NXP Semiconductors, Eindhoven, the Netherlands
国际会议
北京
英文
1195-1200
2009-08-10（万方平台首次上网日期，不代表论文的发表时间）