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arXiv · 2601.16416

Low-Loss, High-Coherence Airbridge Interconnects Fabricated by Single-Step Lithography

Jibang Fu·Bo Ren·Jiandong Ouyang·Cong Li·Kechengqi Zhu·Yonggang Che·Xiang Fu·Shichuan Xue·Zhaohua Yang·Mingtang Deng·Junjie Wu
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Abstract

Airbridges are essential for creating high-performance, low-parasitic interconnects in integrated circuits and quantum devices. Conventional multi-step fabrication methods hinder miniaturization and introduce process-related defects. We report a simplified process for fabricating nanoscale airbridges using only a single electron-beam lithography step. By optimizing a multilayer resist stack with a triple-exposure-dose scheme and a thermal reflow step, we achieve smooth, suspended metallic bridges with sub-200-nm features that exhibit robust mechanical stability. Fabricated within a gradiometric SQUID design for superconducting transmon qubits, these airbridges introduce no measurable additional loss in the relaxation time $T_1$, while enabling a 2.5-fold enhancement of the dephasing time $T_2^*$. This efficient method offers a practical route toward integrating high-performance three-dimensional interconnects in advanced quantum and nano-electronic devices.

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Jibang Fu, Bo Ren, Jiandong Ouyang, Cong Li, Kechengqi Zhu, Yonggang Che, Xiang Fu, Shichuan Xue, Zhaohua Yang, Mingtang Deng, Junjie Wu. 2026-01-23. Low-Loss, High-Coherence Airbridge Interconnects Fabricated by Single-Step Lithography. https://arxiv.org/abs/2601.16416

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