Modeling and Experimental Correlation of Bga Solder Joints under Pcb Bending

This study addresses the effects of varying configurations in board-level 4-point bend testing of BGA packages. The IPC/JEDEC 9702 test method employs 4-point monotonic PCB bending at high strain rates to characterize the PCB strains required to cause board level interconnection failures [1]. While this test is widely used, at present there is little published documentation of the resultant strain distribution at the BGA solder joints. Furthermore, the IPC-9702 test allows flexibility in various test variables such as the number of components on a board, component size/construction, and test board dimensions. In this paper 3-D finite element modeling has been used to compute the strain distribution in BGA solder joints subjected to 4-point PCB bending. The FEA model has been validated with experimental strain gage data obtained from different component sizes. The effects of varying test configurations such as the use of a single component or multiple components on a board, component size, and package construction have been studied. In addition, the possibility of using bare BGA substrates for 4-point bend testing has been examined.