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Rhodora Zaide, Aleli Velarde, Roseller Felipe, Allegro Microsystems Phils., Inc.
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This paper describes how vacuum sealing can be employed to prolong the storage of leadframes without any significant negative effect on their quality. Vacuum sealing of leadframes involves putting the leadframes inside a pouch, evacuating the air from the pouch by purging it with nitrogen gas, and subsequently sealing the pouch with a vacuum sealer. This technique prevents atmospheric air and contaminants from reaching the leadframes under storage. In this study, the functionality and quality of stored leadframes were assessed at different points in time using a variety of tests, e.g., die shear testing, wire pull testing, and resin bleed testing. Statistical tools were then applied on the data to check for any degradation in the leadframes. This paper showed that leadframes can be stored under vacuum-sealed conditions for up to 4 years without exhibiting any bondability or quality problems during assembly. This study on prolonged leadframe storage by vacuum sealing was able to reduce the number of evaluations needed to be done on slow-moving leadframe materials prior to their actual use on the line.
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