Extensible 3D architecture for superconducting quantum computing

Abstract

Using a multi-layered printed circuit board, we propose a 3D architecture suitable for packaging supercon- ducting chips, especially chips that contain two-dimensional qubit arrays. In our proposed architecture, the center strips of the buried coplanar waveguides protrude from the surface of a dielectric layer as contacts. Since the contacts extend beyond the surface of the dielectric layer, chips can simply be flip-chip packaged with on-chip receptacles clinging to the contacts. Using this scheme, we packaged a multi-qubit chip and per- formed single-qubit and two-qubit quantum gate operations. The results indicate that this 3D architecture provides a promising scheme for scalable quantum computing

3D integrated superconducting qubits

“…A previous experiment used a flip-chip architecture with large sapphire spheres setting the spacing between two chips [19], but the assembly method used was not scalable and lacked galvanic connection between the chips. More recent efforts have focused on scalable vertical interconnects [20][21][22], but these approaches have not yet demonstrated compatibility with high-coherence superconducting qubits.…”

Solid-State Qubits: 3D Integration and Packaging

“…For example, the authors of Ref [32] use pogo pins to make contact between a PCB and an array of seven qubits on a silicon chip with an interior qubit that cannot be addressed laterally, and the authors of Ref [33,34] use a novel double-sided coaxial line approach to capacitively couple to qubits for control and read out. Researchers have also flipped a silicon chip with 13 qubits directly on top of a PCB, making contact by pushing the silicon chip against vias in the PCB signal lines [35]. Finally, a concept called the "quantum socket" uses custom spring-loaded micro-wires to make contact between pads on the silicon chip and standard microwave connectors [36].…”

Tunable coupling of widely separated superconducting qubits: A possible application towards a modular quantum device

“…Integrating an increasing number of qubits without scarifying qubit performance, especially in monolithic quantum devices, requires overcoming several scientific and technical challenges, such as wiring problem [7][8][9], crosstalk [10][11][12], and fabrication yield [13,14]. To overcome these limitations, various schemes have been proposed and demonstrated, such as the compact integration of superconducting quantum devices with the classical cryogenic control systems [15][16][17][18][19], the three-dimensional (3D) integration technologies [20][21][22][23][24][25], and the post-processing of the fabricated qubit devices [26][27][28].…”