Electrical contact failure mechanisms relevant to electronic packages

The most common failure mechanisms for electrical contacts are classified, defined, and discussed. Time- and temperature-dependent mechanisms include metallurgical diffusion, surface migration, evaporation, decomposition, outgassing, stress relaxation, and creep. Concentration gradients and mechanical loads also affect the rate of these mechanisms. Other mechanisms are induced from a mismatch in coefficient of thermal expansion and are triggered by thermal cycling. Corrosion mechanisms result from corrosive gases and particulates. Wear mechanisms result from motion at interfaces. Mechanical failures occur from structural defects and foreign particulate contamination. Various parameters influence these failure mechanisms. The ultimate single effect is a degradation of the contact interface resulting in high contact resistance, an open, or an intermittent open. It is concluded that, with sound understanding, these failure mechanisms and their undesirable effects can be avoided by appropriate connector design or selection, implementation, and quality control.<
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