Bonding wire profile for minimizing vibration fatigue failure

摘要

Any two segments of a wire bonded on two bond pads at different elevations can be distinguished by a stationary node (or zero-displacement) during its second-mode vibration. In order to boost the natural frequency of such a bond wire to avoid a second-mode resonance occurring at the lowest frequency in the in-plane vibration, a wire can be optimized by connecting two equalized (shortest possible) wire segments to replace a wire consisting of a larger segment and a shorter segment. The purpose is to re-distribute a larger vibration movement in the longer segment with a lower stiffness of an arbitrary bond wire to two smaller equalized segments of an optimized wire to reduce an in-plane vibration to significantly improve the wire natural frequency and reliability in a harsh vibration environment such as over 30 kHz.