Shelf-Life Evaluation of Lead-

The integrated circuit (IC) industry is converting to lead (Pb)-free termination finishes for
leadframe-based packages. IC component users need to know the maximum length of time
that components can be stored prior to being soldered. This study predicts shelf life of the
primary Pb-free finishes being proposed by the industry. Components were exposed to a
controlled environment, with known aging acceleration factors. The Pb-free components
were exposed to a Battelle Class 2 environment both in and outside of their normal packing
materials. Results show that the Pb-free-finished ICs stored in tubes, trays, or tape-and-reel
packing material pass solderability testing after 96-h exposure to the Class 2 environment.
This exposure correlates to eight years in an uncontrolled indoor environment, such as a
warehouse.