Modeling and Analysis of Signal Integrity of High-Frequency Transmission Channel With Degraded Fuzz Button Connectors

Fuzz button connectors are extensively used in vertical interconnection for high-density integrated circuits. However, fuzz buttons operating in harsh environments for extended periods are subject to degradation, which may directly affect the communication systems reliability. In this work, the specific effects of fuzz button degradation on its electrical properties are studied by theoretical and experimental analysis. The surface morphology and contact states of the metal wires inside the degraded samples are observed to analyze the degradation mechanism. The equivalent circuit models for the transmission channel with fuzz buttons before and after degradation are developed to evaluate signal reflection and transmission loss. The equivalent impedance networks of the fuzz button interconnections with slight and severe degradation levels are proposed and the corresponding parasitic electrical parameters of the equivalent impedance networks are also calculated and analyzed. Finally, fuzz buttons with different degradation levels are obtained by accelerated tests and the experiment tests are conducted to validate the equivalent circuit model results. The results of experimental test and equivalent circuit model are compared and show good agreement. The research results provide a better understanding of the electrical characteristics of degraded fuzz buttons and theoretical guidance for improving electronic system reliability.