Solid-state qubits integrated with superconducting through-silicon vias

TL;DR

This paper demonstrates the integration of superconducting through-silicon vias with qubits, enabling dense 3D superconducting qubit arrays with high-fidelity control and readout, advancing scalable quantum computing architectures.

Contribution

It introduces the first integration of high-aspect ratio superconducting TSVs with qubits, supporting dense 3D superconducting qubit arrays without performance loss.

Findings

Successful fabrication of superconducting TSVs with 10 μm width and 200 μm depth.

High-fidelity microwave readout achieved using TSV-based control.

Qubits fabricated directly on TSV-integrated chips.

Abstract

As superconducting qubit circuits become more complex, addressing a large array of qubits becomes a challenging engineering problem. Dense arrays of qubits benefit from, and may require, access via the third dimension to alleviate interconnect crowding. Through-silicon vias (TSVs) represent a promising approach to three-dimensional (3D) integration in superconducting qubit arrays -- provided they are compact enough to support densely-packed qubit systems without compromising qubit performance or low-loss signal and control routing. In this work, we demonstrate the integration of superconducting, high-aspect ratio TSVs -- 10 $\mu$m wide by 20 $\mu$m long by 200 $\mu$m deep -- with superconducting qubits. We utilize TSVs for baseband control and high-fidelity microwave readout of qubits using a two-chip, bump-bonded architecture. We also validate the fabrication of qubits directly upon the surface of a TSV-integrated chip. These key 3D integration milestones pave the way for the control and readout of high-density superconducting qubit arrays using superconducting TSVs.