Superconducting Vias for Multi-Planar Quantum Circuit Interconnects
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Solution Overview
Problem
Current quantum computing technologies face challenges in providing efficient electrical connections for quantum circuits, particularly as the number of qubits increases, due to limitations in wirebonding methods that restrict scalability and hinder multi-planar connections, and require lossless transmission of low-intensity signals.
Innovation Solution
A metallization stack with superconducting signal and ground vias, fabricated using deep-reactive-ion-etched openings with conformally coated superconducting material, providing DC to microwave-frequency lossless connectivity between different planes of a quantum IC package, enabling multi-planar quantum circuits and efficient signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wirebonding is used to provide electrical connections, then the quantum processor can be assembled with current limited number of qubits, but it faces significant challenges when scaled to accommodate quantum processors with much larger number of qubits due to insufficient edge space and inability to support multi-planar connections
Solution Approach 1:
The patent transitions from two-dimensional wirebonding at the chip edge to three-dimensional vertical vias through the chip substrate. This dimensional change enables connections to multiply stacked quantum circuit planes, allowing scalability to large numbers of qubits without being constrained by peripheral edge space. The vertical via structure provides inter-planar connectivity that wirebonding cannot achieve.
2Adaptability or versatility
If traditional wirebonding is used, then current quantum processors can be connected, but multi-planar quantum circuits cannot be electrically connected as circuit elements in different planes are excluded from connection
Solution Approach 1:
The invention introduces vertical via structures that extend through the substrate to connect circuit elements across multiple planes. This three-dimensional interconnection approach enables multi-planar quantum circuits to be electrically connected, allowing circuit elements in different planes to communicate. The via-based methodology provides a manufacturing pathway for stacked quantum circuit architectures.
3Reliability
If conventional interconnects are used, then connections can be provided, but signals with very small intensity (single photon or less) cannot be transmitted losslessly
Solution Approach 1:
The patent changes the physical parameters of the interconnect material by using superconducting material for the via structures. This parameter change enables lossless transmission of microwave signals with very small intensity (single photon or less) by eliminating resistive losses that would otherwise degrade the quantum signals. The superconducting property maintains signal fidelity while allowing extremely low-power operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables reliable, scalable, and lossless electrical connectivity for quantum circuits, supporting the operation of qubits at cryogenic temperatures and facilitating the integration of multiple quantum circuit components across different levels, thereby enhancing the performance and scalability of quantum processors.
Implementation Method 1
providing DC to microwave-frequency lossless connectivity between different planes of a quantum IC package
Data Source
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AI summary
Embodiments of the present disclosure provide a metallization stack that includes a superconducting signal via extending between a patterned top superconducting surface and a patterned bottom superconducting surface of a substrate, and a plurality of superconducting ground vias extending between the patterned top and bottom surfaces of the substrate substantially parallel to the signal via. The superconducting ground vias may be arranged in a ring, with the signal via being at a center of the ring. The signal via and the plurality of ground vias are configured to provide DC to microwave-frequency connectivity to at least one quantum circuit component housed by the substrate by virtue of each via being implemented as an opening having inner sidewalls coated with a layer of a superconducting material having a thickness of at least 50 nanometers.