Ball grid array reliability assessment for aerospace applications

Reliability of ball grid arrays (BGAs) was evaluated with special emphasis on space applications. This work was performed as part of a consortium led by the Jet Propulsion Laboratory (JPL) to help build the infrastructure nec essary for implementing this technology. Nearly 200 test vehicles, each wit h four package types, were assembled and tested using an experiment design. The most critical variables incorporated in this experiment were package t ype, board material, surface finish, solder volume, and environmental condi tion. The packages used for this experiment were commercially available pac kages with over 250 I/Os including both plastic and ceramic EGA packages. The test vehicles were subjected to thermal and dynamic environments repres entative of aerospace applications. Two different thermal cycling condition s were used, the JPL cycle ranged from -30 degrees C to 100 degrees C and t he Boeing cycle ranged from -55 degrees C to 125 degrees C. The test vehicl es were monitored continuously to detect electrical failure and their failu re mechanisms were characterized. They were removed periodically for optica l inspection, scanning electron microscopy (SEM) evaluation, and cross-sect ioning for crack propagation mapping. Data collected from both facilities w ere analyzed and fitted to distributions using the Weibull distribution and Coffin-Manson relationships for failure projection. This paper will descri be experiment results as well as those analyses. (C) 1999 Elsevier Science Ltd. All rights reserved.