Investigation on the electro-mechanical behavior and reliability of fuzz button interconnects of 3D electronic assembly

With the rapid advancement of integrated circuit technology, three-dimensional (3D) electronic assembly and vertical interconnection have become critical approaches for enhancing device integration density and performance. Fuzz buttons, as a novel solderless elastic interconnection technology, have been widely adopted in aerospace, military, and high-density electronic assembly applications due to their high reliability, excellent vibration resistance, and elimination of high-temperature soldering processes. In this study, the mechanical properties, electrical performance, and reliability of fuzz buttons were systematically investigated. Quasi-static tests were first conducted to evaluate the mechanical and electrical characteristics of fuzz buttons fabricated from different materials. Subsequently, a three-layer 3D circuit assembly was implemented using dual-sided bump interposer bonding and copper wire-based parallel narrow-gap resistance welding technologies. The assembled 3D circuit module was subjected to high–low temperature thermal shock and random vibration tests to assess its reliability under harsh environmental conditions. The results demonstrate that fuzz buttons exhibit pronounced nonlinear mechanical behavior and maintain low contact resistance. Furthermore, stable electrical performance was observed after thermal shock and random vibration testing, indicating excellent environmental reliability. These findings provide important experimental evidence and theoretical support for the application of fuzz button interconnection technology in high-density 3D assembly systems.