A Novel Bumping Method for Flip-Chip Interconnection

In this paper, a novel bumping method for the flip-chip interconnection is proposed, which can be used in the multichip modules (MCM) of superconducting circuits. The silicon bump was prepared by the etching method, and surface was metalized by sputtering niobium metal, which was used for the interconnection between the chip and the substrate. Through electromagnetic simulation, the silicon bump can achieve the transmission performance of
$\mathbf{S}_{11} \mathbf{\leqslant-15} \mathbf{dB}\ \mathbf{and}\ \mathbf{S}_{21} \geqslant$
-1dB in the range of 1-100GHz. By using superconducting materials, superconducting interconnection can be realized. And its excellent high-frequency transmission performance shows that silicon bump can be used for multi-chip interconnection of superconducting integrated circuits.