In thermal cycling tests comparing the board-level reliability of SMD versus NSMD PBGA solder pads, packages incorporating the NSMD pads were observed to last much longer. No failures were detected through 15,000 0 to 100°C cycles on NSMD packages built onto NSMD test board pads. Four failures of NSMD packages on SMD test board pads detected up to 12,556 cycles appeared to be premature and may not be bulk solder fatigue related as no additional events have occurred on these configurations. These four failures will be investigated further.
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