Comparative Study on Impact Of Various Low Creep Doped Lead Free Solder Alloys
Authors: Anto Raj, Sharath Sridhar, Sivasubramanian Thirugnanasambandam, Thomas Sanders, Ph.D., John Evans, Ph.D., Wayne Johnson, Ph.D., Mark Carpenter, Ph.D., Sa’d Hamasha, Ph.D. Company: Auburn University Date Published: 9/17/2017
Abstract: This experiment considers the reliability of 15mm and 17mm BGA and evaluates them on 0.200” power computing printed circuit boards. Additionally, various doped low creep lead free solders designed for hightemperature reliability are considered such as SAC+Sb, SAC405+Dopants, SAC+Sb+Bi+0.15Ni and SAC+Sb+Bi+0.02Ni. The performance of those lead-free solders is compared with Tin-Lead (SnPb) and SAC305. The effect of isothermal aging at 75°C for 6months is also considered for these pastes. The principal test components are 15mm and 17mm ball grid array (BGA) packages. These Single-sided assemblies were built separately for the Topside and Bottom-side of the boards. The board substrate used in this assembly is Megatron6. The assemblies were subjected thermal cycles of -40°C to +125°C on a 120- minute thermal profile with 15-minute dwell time and 45- minute transition time. The test was subjected to JEDEC JESD22-A104-B standard high and low temperature test in a single-zone environmental chamber to assess the solder joint performance. It is found that SAC405+Dopants performed better than SAC305, SnPb and other lead free solder pastes after 6months of aging at 75°C. Survival curves of solder paste performance are compared. It is found that the survival function for at least one of the solder paste is different at 5% level of significance.
BGA, High Reliability Solder, Doping, PCB, Reliability, Solder, lead free