Effects of Solder Joint Shape on Joint Reliability Under Drop Impact Loadings

The purpose of this paper is to compare the ability of solder joint with different shape (hourglass-shaped, barrel-shaped and cylinder-shaped) to resist destruction under drop impact loadings. Three 3D finite element models of VFBGA (very-thin-profile fine-pitch BGA) packages, including different shape of solder joints, are established respectively. According to the condition B in the drop test standard of JEDEC, the stress-strain responses of the whole packages under drop impact loadings are calculated by ANAYA/LS-DYNA. The results showed that the stress on the solder joint reaches its peak at about 1ms and the maximum peeling stress on the critical solder joint which is located at the most outer corner of the BGA package. The hourglass-shaped solder joints which show the minimum peeling stress at the critical moment, have the strongest ability to resist destruction among three shaped solder joints under drop impact loadings.