Enabling technologies for increased circuit complexity of high-coherence superconducting qubits: Part 2*

As quantum computing with superconducting qubits increases in complexity, 3D integration will enable increased density of control and readout circuitry. One approach is to bond chips that perform different functionalities using indium bumps. MIT Lincoln Laboratory has integrated silicon hard-stop mesas to achieve reliable spacing and tilt between chips during bump bonding. Here we will describe further development of hard-stop mesas, assessment of tilt and integration into high-coherence superconducting qubit fabrication.