Design and Operation of Wafer-Scale Packages Containing >500 Superconducting Qubits

TL;DR

This paper introduces a wafer-scale package supporting over 500 superconducting qubits, demonstrating high coherence, fidelity, and thermal robustness, enabling large-scale quantum computing and high-throughput qubit testing.

Contribution

The work presents a novel wafer-scale packaging architecture for superconducting qubits that supports over 500 qubits with maintained performance and thermal stability, advancing large-scale quantum processor development.

Findings

Median qubit T1 and T2e times of ~100 μs for ~100 qubits

Median readout fidelity of 97.5% for 54 qubits

Package operates in commercial dilution refrigerators

Abstract

Packages capable of supporting large arrays of high-coherence superconducting qubits are vital for the realisation of fault-tolerant quantum computers and the necessary high-throughput metrology required to optimise fabrication and manufacturing processes. We present a wafer-scale packaging architecture supporting over 500 qubits on a single 3-inch die. The package is engineered to suppress parasitic RF modes, and to mitigate material loss through simulation-informed design while managing differential thermal contraction to ensure robust operation at millikelvin temperatures. System-level heat-load calculations from a large wiring payload show this package may be operated in commercial dilution refrigerators. Measurements of the qubits loaded into the package show median $T_1$, $T_{2e} \sim 100~\mu$s ($\sim$100 qubits) alongside readout with median fidelity of 97.5% (54 qubits) and a median qubit temperature of 36 mK (54 qubits). These results validate the performance of these packages and demonstrate that large-scale integration can be achieved without compromising device performance. Finally, we highlight the utility of these packages as a tool for high throughput feedback on qubit figures of merit over large sample sizes, allowing identification of performance outliers in the tails of the coherence distribution, a critical capability for informing fabrication and manufacture of high-quality quantum qubits and quantum processors.