Low-Temperature Glass Bonding for Microfluidic Devices

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Solution Overview

Problem

The high bonding temperature required for glass substrates in micro/nano-channel devices damages the patterned biological substances and electrodes, making it difficult to achieve accurate and reliable functional device manufacturing with glass substrates.

Innovation Solution

A method involving glass substrates with a fluorine concentration of 0.6-3.5 at% and F-Si bonds, bonded at 25°C to 100°C with a silane coupling agent, to form micro/nano-scale flow paths with enhanced bonding strength and pressure resistance, allowing for accurate patterning of capture bodies and electrodes without thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass substrates are bonded at high temperature (1000°C or higher), then strong bonding strength is achieved, but the patterned biological substances and electrodes are thermally damaged

Engineering Contradiction:
Improvebonding strengthVSAvoidthermal damage to modification objects
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the bonding temperature parameter from conventional high temperature (1000°C or higher) to low temperature (25°C to 100°C). This parameter change enables strong bonding of glass substrates without thermally damaging the patterned biological substances, electrodes, and other modification objects on the substrate surface

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces fluorine-containing substances as intermediaries to facilitate low-temperature bonding. The fluorine-containing substance forms a bonding interface between glass substrates at low temperatures, enabling strong adhesion without requiring high heat that would damage sensitive modification objects

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If glass substrates are used for micro/nano-channel devices, then high strength, solvent resistance, and optical transparency are achieved, but high bonding temperature damages the functional materials

Engineering Contradiction:
Improvesolvent resistance and optical transparencyVSAvoidthermal damage to biological substances and catalysts
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the bonding temperature parameter to enable glass substrate processing at low temperatures (25°C to 100°C), preserving the integrity of biological substances, catalysts, and electrodes while maintaining the reliability benefits of glass materials including solvent resistance and optical transparency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs patterning of biological substances, electrodes, and catalysts on the glass substrate surface before bonding. By completing these sensitive operations beforehand and then bonding at low temperature, the functional materials are protected from thermal damage while achieving reliable glass substrate devices

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If soft materials like elastomer are used for micro-channels, then easy bonding is achieved, but nanoscale channels are easily closed due to deformation

Engineering Contradiction:
Improveease of bondingVSAvoidchannel openness and dimensional stability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses glass substrates for both the channel structure and bonding layers, ensuring homogeneous material properties throughout. This homogeneity provides dimensional stability and prevents deformation that would close nanoscale channels, while still achieving ease of bonding through low-temperature processing with fluorine-containing substances

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The patent creates a composite structure using glass substrates with fluorine-containing substances as the bonding interface. This composite approach combines the dimensional stability and chemical resistance of glass with the bonding ease previously associated with soft materials, eliminating the trade-off between ease of manufacture and manufacturing precision

Inventive Principle:
Principle #40Composite materials

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 enables the creation of functional devices with high accuracy and reliability, preventing thermal damage to capture bodies and electrodes, and maintaining the desired functional properties while ensuring leak-proof and pressure-resistant micro/nano-scale flow paths.

Implementation Method 1

the bonding portion between the one surface of the first substrate and the one surface of the second substrate includes a F-Si bond in which fluorine is bonded to silica included in at least one substrate

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

bonded at 25°C to 100°C with a silane coupling agent

Methodology Applied
Scientific EffectSilane coupling: Chemical Bonding

Data Source

PatentEP2902104B1Functional device and functional device manufacturing method
Publication Date: 2019.05.22 THE JAPAN SCI & TECH AGENCY
  • EP2902104B1 patent drawingFigure 1~2
  • EP2902104B1 patent drawingFigure 3~4
  • EP2902104B1 patent drawingFigure 5

AI summary

A functional device (and a functional device manufacturing method) includes a first substrate in which a groove is formed in one surface, a second substrate which is integrally disposed by bonding one surface of the second substrate to the one surface of the first substrate, and forms a flow path together with the groove of the first substrate, at least one modification object of a capture body which captures a target substance supplied into the flow path, an electrode which imparts an electrical or a chemical action to the target substance, and a catalyst, in which the modification object is disposed by being modified on a part of an inner surface of the flow path, a bonding portion between the one surface of the first substrate and the one surface of the second substrate is formed by bonding fluorine to silica.