Design and operation of packages for monolithic 3" devices containing >500 superconducting qubits

The physical qubit requirement of fault-tolerant quantum computers necessitates packages containing larger numbers of superconducting qubits. In this work, we describe the design and operation of a non-contact microwave probe card which can be considered a readout module for a wafer-scale quantum processor and contains >500 qubits. We show how we address the design challenges of parasitic mode mitigation, packaging-induced microwave losses and the effects of thermal contraction for monolithic devices made from 3" wafers. We show the measurements of > 100 qubits from one of these devices with median T1, T2e ~100 μs. We demonstrate the value of these types of device for high-throughput measurements of qubits, showing why these high N studies are important as feedback to optimise manufacturing protocols.