摘要 |
A plurality of vertically spaced-apart microsprings are provided to increase microspring contact force, contact area, contact reliability, and contact yield. The microspring material is deposited, either as a single layer or as a composite of multiple sub layers, to have a tailored stress differential along its cross-section. A lower microspring may be made to push up against an upper microspring to provide increased contact force, or push down against a substrate to ensure release during manufacture. The microsprings may be provided with similar stress differentials or opposite stress differentials to obtain desired microspring profiles and functionality. Microsprings may also be physically connected at their distal ends for increased contact force. The microsprings may be formed of electrically conductive material or coated with electrically conductive material for probe card and similar applications.
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