Solder fatigue arrest for wafer level package

摘要

A wafer level package includes a wafer, a lead disposed of the wafer for connecting the wafer to an electrical circuit, and a core disposed of the lead. In some embodiments, the lead disposed of the wafer is a copper pillar, and the core is plated onto the copper pillar. In some embodiments, the core is polymer screen-plated onto the lead. In some embodiments, the core extends between at least approximately thirty-five micrometers (35 μm) and fifty micrometers (50 μm) from the lead. In some embodiments, the core covers between at least approximately one-third (⅓) and one-half (½) of the surface area of the lead. In some embodiments, the core comprises a stud-shape extending from the lead. In some embodiments, the core extends perpendicularly across the lead. In some embodiments, the core extends longitudinally along the lead. Further, a portion of the core can extend perpendicularly from a longitudinal core.

主权项

1. A wafer level package comprising:
a wafer; a longitudinal lead disposed on the wafer for connecting the wafer to an electrical circuit, the lead configured to transmit heat between the wafer level package and the electrical circuit; a longitudinal non-fatigue polymer core extending along a length of the lead; a plurality of polymer cores periodically extending perpendicularly from the longitudinal non-fatigue polymer core along the length of the lead, at least one of the plurality of polymer cores extending from the longitudinal non-fatigue polymer core at an intermediate location along the length of the longitudinal non-fatigue polymer core; and solder deposited on the longitudinal non-fatigue polymer core and the plurality of polymer cores.