Presentation Information
[18p-S2_202-9]TSV-free wireless signal interconnects between substrates for superconducting quantum circuits
Miyuki Ozawa1, Shigeru Kawakami1, 〇Yutaka Tabuchi1 (1.RIKEN RQC)
Keywords:
superconducting qubit,3-dimenstional integration
Three-dimensional integration of superconducting qubits and peripheral circuits is essential for scaling quantum computers. Currently, two-layer circuits using indium bumps with vacuum gaps have often been employed, as significant dielectric loss remains a concern for qubit performance. To explore further integration with low-loss materials, we research wiring technologies based on chip-to-chip stacking, utilizing the silicon substrate itself as a low-loss insulator. Whereas through-silicon vias (TSVs) are typically used for signal transmission between substrate-surface circuits, they face challenges: open vias complicate subsequent fabrication processes, and filled vias often utilize lossy non-superconducting materials.
In this study, we propose a novel inter-substrate signal transmission technology that eliminates the need for through-substrate vias. Exploiting microwave frequencies for qubit control and readout, we designed a transmission line that guides signals through displacement current, rather than conventional conduction current. We form spiral resonators on each side of the stacked substrates and a readout resonator for superconducting qubits in the inner layer, which is capacitively coupled to the TSV-free transmission line. Measurement results demonstrate successful wireless transmission near the resonance frequency of the spiral resonators, verifying the effectiveness of the proposed signal transfer mechanism.
In this study, we propose a novel inter-substrate signal transmission technology that eliminates the need for through-substrate vias. Exploiting microwave frequencies for qubit control and readout, we designed a transmission line that guides signals through displacement current, rather than conventional conduction current. We form spiral resonators on each side of the stacked substrates and a readout resonator for superconducting qubits in the inner layer, which is capacitively coupled to the TSV-free transmission line. Measurement results demonstrate successful wireless transmission near the resonance frequency of the spiral resonators, verifying the effectiveness of the proposed signal transfer mechanism.