Investigation of signal integrity of fuzz button connectors under different compression states

Abstract

AbstractFuzz button connectors are extensively used in vertical interconnection for high‐density integrated circuits. This work studied the impact of fuzz buttons under different compression states on high‐frequency signal transmission using theoretical analysis and experimental testing. The resistance values for fuzz buttons with different heights in compression states were measured. The physical dimensions were obtained for sample fuzz buttons subjected to various compression states. The effects of long‐term compression of fuzz button on the resistance values and S parameters of the device under test (DUT) were analyzed. In addition, the high‐frequency parameters were measured for the DUT with fuzz buttons in various compression states. Both a three‐dimensional (3D) electromagnetic field model and an equivalent circuit model for the fuzz buttons under compression states were developed and the results of these two models show good agreement with experimental results. In the circuit model, a fuzz button connector with a three‐wire transmission line structure was modeled as a π impedance network, composed of equivalent inductances and capacitances. It was found that the proposed 3D electromagnetic field model and an equivalent circuit model can accurately predict the effect of fuzz buttons under different compression states on the signal transmission in the affected frequency band. However, the models cannot evaluate the communication performance of the whole system.