Lead Etching for Semiconductor-Superconductor Hybrid Fabrication

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Solution Overview

Problem

Existing methods for fabricating semiconductor-superconductor hybrid devices, particularly those involving topological quantum computing, face challenges in efficiently etching superconductor materials like lead without damaging underlying semiconductor components or the etching mask, and in forming effective passivating layers to protect the semiconductor from degradation.

Innovation Solution

A method involving the use of an etchant composition comprising acetic acid and propan-2-ol to selectively etch lead while forming a passivating layer on the semiconductor component, using a mask to protect the semiconductor from oxidation and etching, and ensuring good energy coupling between superconductor layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional etching methods are used to remove lead, then the lead can be etched, but the underlying semiconductor component and etching mask are damaged

Engineering Contradiction:

Improveetching precisionVSAvoiddamage to semiconductor and mask

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs an intermediary protective layer (such as alumina or silica) deposited over the semiconductor component before etching. This intermediary layer acts as a barrier that prevents the etchant from directly contacting and damaging the semiconductor and mask, while still allowing selective etching of the lead through controlled application of the etchant to exposed regions

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a disposable protective coating applied to the mask and semiconductor areas that are not intended for etching. This sacrificial layer is designed to be removed after the etching process, having served its purpose of protecting underlying structures during the etching operation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Productivity

If the semiconductor is exposed during etching, then the lead can be etched, but the semiconductor oxidizes and degrades

Engineering Contradiction:

Improveetching efficiencyVSAvoidsemiconductor integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent conducts the etching process in an inert atmosphere (such as nitrogen or argon environment) to prevent oxidation of the semiconductor component. This inert environment eliminates oxygen and moisture that would otherwise cause degradation of the exposed semiconductor during the etching process

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent applies a protective coating or capping layer to the semiconductor component before the etching process begins. This preliminary protective action ensures that even if the semiconductor is exposed during etching, it remains protected from oxidation and degradation, allowing the etching to proceed efficiently

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a mask is used to protect the semiconductor, then the semiconductor is protected, but the mask itself degrades from the etchant

Engineering Contradiction:

Improvesemiconductor protectionVSAvoidmask integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent introduces an intermediary protective layer between the etchant and the mask material. This intermediary layer (such as a deposited oxide or polymer coating) is resistant to the etchant and protects the mask from degradation, while still allowing the etchant to selectively remove the lead through controlled application

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a sacrificial protective coating on the mask that is designed to degrade or be removed after serving its protective function. This disposable layer absorbs the etchant's harmful effects, protecting the underlying mask structure while being consumed in the process

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 method effectively etches lead without damaging the semiconductor or the mask, forming a protective passivating layer that maintains semiconductor integrity and enables efficient electron transport and protection from environmental corrosion.

Implementation Method 1

contacting the exposed regions with an etchant composition. The etchant composition comprises acetic acid and propan-2-ol

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 2

forming a mask on the layer of lead, the mask defining exposed regions of the layer of lead

Methodology Applied

Scientific EffectPhysical barrier protection:

Data Source

PatentEP4354358B1Fabrication of a semiconductor-superconductor hybrid device

Publication Date: 2026.03.11 MICROSOFT TECHNOLOGY LICENSING LLC

Figure 1
Figure 2a~2d
Figure 2e~2g

AI summary

A method of etching a workpiece comprising a lead component (24) is provided. The method comprises forming (301) a mask on the lead component (24), the mask defining exposed regions of the lead component (24); and contacting (302) the exposed regions with an etchant composition. The etchant composition comprises acetic acid and propan-2-ol.