Design and Characterization of 3D-Integrated Superconducting Qubit Lattices*

Superconducting qubits hold the promise of individual qubit control and readout, with broad tunability of qubit frequencies and coupling strengths. However, in-plane interconnect routing becomes prohibitive for even moderately sized lattices due to space constraints. Here, we incorporate flip-chip 3D integration technology in the design of mesoscale qubit lattices. This allows us to reduce interconnect density and enables the control and readout of all qubits in larger-scale processors. We report on the improvements to loss and crosstalk enabled by 3D integration.