Robustness of advanced surface mount technology for space applications

Advanced surface mount technology, which includes ball grid array packaging, is quickly becoming a preferred technology for ground based applications. Compared to leaded quad flat packs, ball grid array packaging offers increased manufacturing yields, reduced parasitics and reworkability. Reliability for space applications is an issue which is being aggressively worked. A methodology for examination of various part type/size/board combinations in terms of thermal cycle reliability has been previously developed (1997). Important factors in determining this reliability are: thermal expansion differences between component packages and the printed wiring board (PWB), processes and materials used in creating the interconnect, and the overall package size dimensions. This paper reviews literature data on the reliability of the advanced surface mountable package/board level interconnect. Experimental data are presented to indicate the importance of board level design and package selection in order to effect optimal reliability. The experimental results were fit to a two parameter Weibull model. The boards containing a constraining core provided a factor of 2 increase in thermal cycle robustness over the conventional glass-epoxy/copper board. The results indicate that the material stack-up within a PWB can have a significant effect on surface mount reliability