Superconducting Qubit Bottom Electrode Interconnection

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Solution Overview

Problem

Conventional methods for fabricating superconducting circuits face challenges such as reduced yield due to complex processes and poor electrical connections between superconducting qubits and other parts of the circuit, leading to reduced performance.

Innovation Solution

A superconducting circuit is designed with a bottom electrode that interconnects the superconducting qubit and other parts of the circuit, formed in a continuous superconducting layer through a simplified fabrication method that eliminates the need for additional interface layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional optical lithography is used to fabricate the superconducting qubit, then the fabrication process is simplified, but the manufacturing precision is insufficient for the small dimension of the superconducting qubit

Engineering Contradiction:

Improvedimensional precision of superconducting qubitVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the fabrication process into two distinct stages: first using e-beam lithography to precisely fabricate the superconducting qubit with its bottom electrode, then using conventional optical lithography to fabricate the rest of the superconducting circuit. This segmentation allows each process to be optimized for its specific requirements, resolving the contradiction between precision and complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a bottom electrode as an intermediary structure that serves dual purposes: it forms part of the superconducting qubit and simultaneously acts as the bottom electrode for the rest of the superconducting circuit. This intermediary approach simplifies the overall fabrication by eliminating the need for separate top electrode fabrication steps while maintaining the precision required for the qubit.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If separate fabrication steps are used for the superconducting qubit and other circuit parts, then the manufacturing precision can be maintained, but the interconnection quality deteriorates due to poor electrical connection at metal interfaces

Engineering Contradiction:

Improveelectrical connection qualityVSAvoidfabrication process steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the bottom electrode of the superconducting qubit with the bottom electrode of the rest of the superconducting circuit into a single continuous structure. This merging eliminates the metal-to-metal interface that causes poor electrical connections, as the continuous superconducting material provides direct electrical connectivity without requiring separate bonding steps or interface layers.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If additional interface layers are added to improve interconnection, then the electrical connection quality improves, but the fabrication process complexity increases and yield decreases

Engineering Contradiction:

Improveinterconnection reliabilityVSAvoidfabrication process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the problematic metal-to-metal interface by using a continuous superconducting bottom electrode structure. Instead of adding interface layers to improve connection, the design removes the source of the connection problem entirely, achieving reliable interconnection through the inherent continuity of the superconducting material without requiring additional fabrication steps.

Inventive Principle:

Principle #2Taking out (Extraction)

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 approach simplifies the fabrication process, improves the electrical connection performance between the superconducting qubit and other parts of the circuit, and addresses the issues of reduced yield and poor connections in conventional methods.

Implementation Method 1

a bottom electrode interconnecting a superconducting qubit and a first part of the superconducting circuit. The bottom electrode comprises a top electrode of the superconducting qubit, and a bottom electrode of the first part of the superconducting circuit

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Implementation Method 2

depositing first superconducting material on the first area and the second area

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS12329043B2Superconducting circuit including superconducting qubits

Publication Date: 2025.06.10 ALIBABA GROUP HOLDING LTD

AI summary

The present disclosure discloses a device and a method for fabricating a superconducting circuit including a superconducting qubit. The superconducting circuit comprises a bottom electrode interconnecting a superconducting qubit and a first part of the superconducting circuit. The bottom electrode comprises a bottom electrode of the superconducting qubit and a bottom electrode of the first part of the superconducting circuit. The bottom electrode of the superconducting qubit and the bottom electrode of the first part of the superconducting circuit are formed in a first superconducting layer.