Low Temperature Solder Paste Characterization for Memory Module and SSD Product Level Reliability Tests

In order to investigate and characterize LTS (low temperature solder paste) performance, 2 types of LTS pastes were selected for Memory module and SSD which are assembled in different forms for test items. For Dual In-line Memory Module (DIMM), reliability testing include temperature cycling with different cycling conditions, biased HAST, vibration TC, module 3pt bend, module torsion, shock, random vibration, and solder joint Bi% mixing area analysis. For Solid State Drive (SSD), evaluated reliability items include temperature cycling, biased HAST, shock, random vibration, and solder joint Bi% mixing area analysis. For sample batches in this study, Bismuth (Bi) mixing area ratio of Hybrid SAC-LTS solder joint is controlled around 30% to 60%, and has higher joint height compared to SACSAC joints. Reliability-wise, performance of temperature cycling is the main challenge among various reliability test items. The improvement strategy of temperature cycling is the key topic discussed in this paper.