Here is the abstract you requested from the HiTEC_2012 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Durability of Microalloyed Lead-Free Solder under Combined Thermal Cycling and Vibration|
|Keywords: Lead-free Solder, Reliability, Accelerated Testing|
|The RoHS ban on lead in electronics has driven industry to find alternatives to the high lead solders that have traditionally been used in high temperature environments. In this study quad flat packs (QFP) and 2512 chip resistors were attached to ENIG finished polyimide printed circuit boards by reflowing commercially available Sn3.5Ag and SAC305, as well as experimental SAC+Mn and SnAg+Cu Nano alloys. High temperature isothermal aging for up to 500 hours was performed to permit the growth of interfacial intermetallic compounds. The thickness and composition of these intermetallic compounds were characterized. A durability assessment was then performed by subjecting the samples to thermal cycling from -40°C to temperatures up to 200°C intermixed with 50G vibration cycling. Failure analysis was performed to explain the durability results. The results show very limited improvements in reliability in the microalloyed samples versus standard SAC305 despite significantly reduced interfacial intermetallic growth.|
|F. Patrick McCluskey, Associate Professor
University of Maryland
College Park, MD