Superconducting Quantum Computer Sample Holder With Cavity Resonance Control
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Solution Overview
Problem
Existing sample holders for superconducting quantum circuits suffer from chip-mode resonance that induces decoherence, necessitating a higher resonance frequency to mitigate its influence.
Innovation Solution
A sample holder design with a pedestal and PCB featuring a through opening and a cavity beneath the PCB, where the cavity extends outward from the opening, supporting the chip with conductive posts to maximize vacuum contact and reduce dielectric interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chip is mounted on a metal pedestal with the rear surface in contact with the pedestal, then the chip is supported and electrically connected, but chip-mode resonance occurs at low frequencies causing decoherence
Solution Approach 1:
The patent extracts the harmful resonance mode by removing the direct contact between the chip rear surface and the metal pedestal. A through-opening is created in the PCB, and the chip is suspended above the metal pedestal using support structures, effectively taking out the chip from the resonant environment while maintaining electrical connection through bonding wires.
Solution Approach 2:
The patent introduces an intermediary structure (support structures and through-opening configuration) between the chip and the metal pedestal. This intermediary arrangement allows the chip to be electrically connected to the pedestal via bonding wires while preventing direct mechanical contact that would cause resonance, thus mediating between electrical connection requirements and resonance suppression.
2Reliability
If the chip is suspended to reduce resonance, then decoherence is reduced, but the chip mounting structure becomes more complex
Solution Approach 1:
The support structures serve multiple functions: they mechanically support the chip, position it above the metal pedestal to prevent resonance, and allow electrical connection through bonding wires. The through-opening configuration also serves as both a structural element and a resonance suppression mechanism, demonstrating multi-functionality that reduces overall system complexity.
3Productivity
If chip size is increased for higher quantum bit count, then computational capability improves, but resonance frequency decreases increasing decoherence
Solution Approach 1:
By extracting the chip from direct contact with the metal pedestal through the through-opening configuration, the patent eliminates the primary source of resonance. This allows larger chips with more quantum bits to be mounted without the resonance frequency decreasing, as the harmful interaction between the chip and pedestal is removed entirely.
Data Source
AI summary
A sample holder includes: a pedestal made of metal; and a PCB (Printed Circuit Board) placed on the pedestal. The PCB includes a through opening that penetrates from a front surface to a rear surface of the PCB. The pedestal includes a cavity bottomed and with a top of the pedestal opened, the cavity formed at a portion corresponding to directly under the through opening on a side of the pedestal on which the PCB is placed. As a configuration on the side on which the PCB is placed, viewed from above, a part of the cavity is protruded outward from the through opening.