Flexible PCB Interconnect Layout for Cryogenic Quantum Circuits
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Solution Overview
Problem
The challenge of connection breakage and damage to driver circuits in ultra-low temperature environments due to shrinkage during temperature reduction is prevalent in quantum devices, particularly in the arrangement of control, write, and read circuits for quantum bits.
Innovation Solution
The quantum device employs a design with a first and second partition defining an ultra-low temperature chamber, where the circuit boards are divided into upper and lower boards connected by flexible circuits, providing deformation and buffering to prevent connection damage during temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid printed circuit board is used to connect driver circuits in ultra-low temperature chamber, then structural stability is improved, but connection breakage occurs due to thermal shrinkage
Solution Approach 1:
The circuit board is divided into a first circuit board located in the ultra-low temperature chamber and a second circuit board located in the low-temperature chamber, with each segment able to independently respond to thermal contraction. This segmentation allows each board to maintain structural stability while avoiding connection breakage by distributing the thermal stress across separate components rather than a single rigid structure.
Solution Approach 2:
A flexible circuit board is used to connect the first and second circuit boards across the partition. The flexible nature of this circuit board allows it to accommodate thermal shrinkage and deformation during temperature reduction without breaking, while still providing reliable electrical connections between the driver circuits and quantum bits.
2Stability of the object's composition
If circuit board is locked between partitions to maintain position, then positional stability is improved, but deformation and connection damage occur during temperature reduction
Solution Approach 1:
The circuit board system transitions from a completely rigid fixed structure to a semi-flexible dynamic structure. The flexible circuit board portion can dynamically adjust its shape and length in response to thermal contraction, while the locked portions maintain positional stability. This dynamic adaptability prevents connection damage while preserving necessary positional stability.
3Productivity
If driver circuit is placed in ultra-low temperature chamber to reduce signal paths, then signal transmission efficiency is improved, but circuit board damage occurs due to extreme cold shrinkage
Solution Approach 1:
The driver circuit is segmented into two parts: the first circuit board with quantum bit interface circuits placed in the ultra-low temperature chamber to maintain short signal paths, and the second circuit board with additional driver circuits placed in the warmer low-temperature chamber. This segmentation allows the system to achieve both short signal paths for efficiency and protection from extreme cold shrinkage for reliability.
Solution Approach 2:
The partition between the ultra-low temperature chamber and low-temperature chamber serves as an intermediary structure that supports both circuit boards. This intermediary allows the system to bridge the temperature difference while maintaining electrical connections, enabling driver circuits to operate in a less extreme environment while still interfacing with quantum bits in the ultra-low temperature chamber.
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
This design effectively prevents connection breakage and damage to the circuit boards by allowing for flexible circuit deformation, ensuring stable signal transmission between the upper and lower circuit boards in extreme temperature conditions.
Implementation Method 1
In the process of reducing temperature significantly, the printed circuit board locked between the upper partition and the lower partition is prone to connection breakage and damage due to shrinkage
Implementation Method 2
the flexible circuit may provide a deformation and buffering effect when the upper circuit board and the lower circuit board are shrunk
Data Source
AI summary
The disclosure provides a quantum device and a microwave device. The quantum device includes a first partition, a second partition, an upper circuit board, a lower circuit board and a flexible circuit. The second partition is arranged below the first partition. The first partition and the second partition are used to define an ultra-low temperature chamber of the quantum device. The upper circuit board, the lower circuit board and the flexible circuit are arranged in the ultra-low temperature chamber. The upper circuit board is disposed on a lower surface of the first partition. The lower circuit board is disposed on an upper surface of the second partition. The flexible circuit is electrically connected between the upper circuit board and the lower circuit board to provide multiple signal paths for mutual signal transmission between the upper circuit board and the lower circuit board.