Advanced 3D Integration Technologies in Various Quantum Computing Devices

As a key approach to augment Moore's Law scaling, 3D integration technologies have enabled small form factor, low cost, diverse, modular and flexible assembly of integrated circuits in the semiconductor industry. It is therefore essential to adopt these technologies to the quantum computing devices which are at the nascent stage and generally require large scale integration to be practical. In this review, we focus on four popular quantum bit (qubit) candidates (trapped ion, superconducting circuit, silicon spin and photon) which are encoded by distinct physical systems but all intrinsically compatible with advanced CMOS fabrication process. We introduce the specific scalability bottlenecks of each qubit type and present the current solutions using 3D integration technologies. We evaluate and classify these technologies into three main categories based on the hierarchy. A brief discussion regarding the thermal management is also provided. We believe this review serves to provide some useful insights on the contributions of interconnect, integration and packaging to the field of quantum computing where rapid development is ongoing.