Experimental Study And Numerical Simulation Of BGA Package Under Vibration Load

Generally, the low-cycle fatigue induced by thermal cycling is the major concern in the reliability of surface mounted technology (SMT) for electronic packaging, but the high-cycle fatigue induced by vibration can also contribute significant effects, especially for applications in automobile, military, and avionic industries.To assess vibration-induced fatigue failures, the dynamic properties of printed circuit board (PCB) play very important roles. In this paper, the dynamic properties of a ball grid array (BGA) assembly are characterized by using vibration test and finite element analysis. Firstly, the BGA package was clamped to the shaker at one end to complete the vibration test. The frequency of the excitation signal range from5Hz to1000Hz. Then, a curve of the frequency response of the testing board is drawn, from which the first three natural frequency is extracted. Secondly, the vibration tests are combined with FEA to calculate the equivalent Young’s Module of PCB. Further more, a comparing test and analysis with mass attached to the free end of PCB is finished to validate the feasibility of the method.After the vibration test, impose a fixed frequency (BGA package the first natural frequency) and different amplitude of sinusoidal excitation when performing the vibration experiment of BGA package. After the vibration experiment, use the method of metallographic analysis and dye test to observe the failure modes of BGA package, solder joint cracks and the crack expansion form, summarizes the distribution of failure solder joint. Because the solder balls are too small for direct measurement of their stresses and strains, FEA is used for obtaining the BGA package in response to vibration loading instead. Then, determine the solder joint’s stress and strain in a dangerous position, as a basis to predict the fatigue life of BGA package.