Liquid-Metal Microfluidic Device Molding for Robust Encapsulation

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Solution Overview

Problem

Traditional methods for preparing microfluidic devices face challenges such as poor encapsulation, complex processes, and limitations in industrial scalability, leading to devices with restricted geometric designs and performance issues.

Innovation Solution

A method involving a shaping mold to form a solid metal, encapsulating it with a cladding layer, and integrating it into a substrate, allowing for the formation of complex microfluidic devices with improved encapsulation and integration, using a liquid metal that can be remelted during substrate curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional 3D direct writing/printing technology is used, then device fabrication is achieved, but encapsulation performance deteriorates and metal oxide layers form on the surface

Engineering Contradiction:
Improveencapsulation performanceVSAvoidfabrication process quality
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by first forming the metal interconnect structure, then applying the cladding layer before final substrate integration. This sequence prevents oxidation during subsequent processing steps by establishing a protective barrier in advance, while maintaining fabrication quality through controlled deposition processes

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs inert atmosphere principles by using cladding layers that create an oxygen-barrier environment around the metal interconnects. This prevents oxidation reactions during device operation and processing by isolating the reactive metal surfaces from ambient oxygen, thereby improving encapsulation performance without compromising manufacturing quality

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Adaptability or versatility

If microchannel injection technology is used, then device fabrication is achieved, but process complexity increases and patterning flexibility is restricted

Engineering Contradiction:
Improvepatterning flexibilityVSAvoidprocess complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the device fabrication into distinct modular steps: metal interconnect formation, cladding layer application, and substrate integration. This modular approach increases patterning flexibility by allowing independent optimization of each step while reducing overall process complexity through standardized procedures

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes parameter changes by varying the deposition conditions, material compositions, and processing temperatures of the cladding layer to achieve desired patterning outcomes. This allows flexible adaptation to different device designs without increasing process complexity, as the same basic工艺流程 can be adjusted through parameter optimization

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If imprinting technology is used, then device fabrication is achieved, but integrated molding quality deteriorates

Engineering Contradiction:
Improveintegrated molding qualityVSAvoidmolding capability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming the metal interconnect structures with precise geometries before substrate integration. This preliminary structuring ensures high integrated molding quality by establishing accurate patterns early in the process, while maintaining ease of manufacture through reusable molds and standardized fabrication steps

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical imprinting processes with deposition-based cladding layer formation. This substitution improves manufacturing precision by enabling atomic-level control over layer thickness and composition, while maintaining ease of manufacture through scalable deposition techniques that eliminate complex mechanical alignment requirements

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If laser processing technology is used, then device fabrication is achieved, but procedure complexity increases and processing adaptability deteriorates

Engineering Contradiction:
Improveprocessing adaptabilityVSAvoidprocedure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by separating device fabrication into distinct process modules: metal deposition, cladding layer formation, and substrate integration. This segmentation improves processing adaptability by allowing independent optimization of each step for different materials and designs, while reducing procedure complexity through standardized, repeatable workflows

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs universality by developing a versatile cladding layer process that can be applied to various metal interconnect materials and substrate types. This multi-functional approach increases processing adaptability across different device configurations while maintaining relatively simple, unified procedures that reduce overall complexity compared to specialized laser processing for each case

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 method enables the production of microfluidic devices with excellent formability, durability, and long service life, suitable for industrial applications, and can integrate with power and signal components for wider applications.

Implementation Method 1

injecting a liquid metal into the groove of the mold, and solidifying the liquid metal to obtain a solid metal

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 2

melting the solid metal and extending at least a part of the electrode outside the substrate

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3822225B1Microfluidic device and preparation method therefor, and microfluidic system
Publication Date: 2025.09.17 INST OF FLEXIBLE ELECTRONICS TECH OF THU ZHEJIANG
  • EP3822225B1 patent drawingFigure 1

AI summary

A microfluidic device and a preparation method therefor, and a microfluidic system. The preparation method comprises: S1, providing a mold having a groove; S2, injecting a liquid metal into the groove, and solidifying the liquid metal to obtain a solid metal; S3, separating the solid metal from the mold, and providing an electrode on the solid metal; S4, forming a coating layer on a surface of the solid metal having the electrode, so that the solid metal is wrapped in the coating layer, and the electrode at least partially protruding out of the coating layer, so as to obtain a prefabricated device; and S5, placing the prefabricated device in a substrate, melting the solid metal and making the electrode at least partially protrude out of the substrate, so as to obtain a microfluidic device (a). The preparation method is simple, the packaging has good performance, the device is highly integrated and is easy for industrialization, the microfluidic device obtained by means of this preparation method is good in molding, excellent in performance, can be widely used, and can be integrated with a power supply, a signal transmitter and a signal receiver to form a microfluidic system.