High-throughput microwave package for precise superconducting device measurement

Abstract

Cryogenic microwave measurement of superconducting quantum devices is complicated by the packaging required to connect devices to control and read out circuitry. In this work, we outline the design and experimental demonstration of a wirebond-free, PCB-free, drop-in microwave package for on-chip superconducting quantum devices. Once a chip is prepared for installation, the proposed package enables device exchange in about 1 min, with no special equipment required. The package is composed of a superconducting aluminum enclosure with a suspended tungsten transmission pin which couples to on-chip resonators in a hanger-style geometry, enabling broadband transmission measurements without on-chip feedlines or wirebonds. The fundamental package cavity mode is far detuned from the 4 to 8 GHz band of interest and does not participate in resonator readout. We demonstrate the use of this package to extract the loss tangent of superconducting ring resonators, measuring a value of (1.10±0.09)×10−6, which agrees with measurements of λ/4 resonators in wirebond-based packaging. This high-throughput measurement system will allow the rapid generation of large datasets for improving superconducting qubit performance, and facilitate time-sensitive surface passivation and oxide regrowth studies.