Integrated Fluidic-Electrical Bonding Layer for Compact Substrate Integration

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Solution Overview

Problem

The existing methods for integrating microfluidic chips into macro-scaled devices require separate processes for fluidic and electrical connections, leading to increased complexity, larger form factors, and inefficiencies that hinder miniaturization and performance.

Innovation Solution

A method for simultaneous fluidic and electrical bonding of substrates using a bonding layer with patterned fluidic pathways and access holes filled with conductive material, allowing for direct connections between electrical contacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate processes are used for fluidic and electrical connections, then each connection type can be optimized independently, but the overall device complexity increases and manufacturing efficiency decreases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges fluidic and electrical connection processes into a single integrated bonding step. The bonding layer contains both fluidic channels and electrical contact pads, allowing simultaneous establishment of both types of connections when substrates are bonded, thereby reducing manufacturing complexity while maintaining connection reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bonding layer serves multiple functions simultaneously: it provides mechanical bonding between substrates, defines fluidic pathways through patterned channels, and establishes electrical connections through conductive contact pads. This multi-functionality eliminates the need for separate processing steps for each connection type

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

2Reliability

If wire bonding and interposer PCB are used for electrical connections, then reliable electrical connections are established, but device form factor increases and miniaturization is hindered

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoiddevice form factor
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent extracts and eliminates the need for interposer PCBs and wire bonds by integrating electrical contacts directly into the bonding layer. The conductive contact pads in the bonding layer provide direct electrical pathways between substrates, removing unnecessary intermediate components and reducing overall device volume

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from three-dimensional wire bonds extending through space to two-dimensional planar conductive paths within the bonding layer. This dimensional change allows electrical connections to be made more compact, enabling device miniaturization while maintaining connection reliability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If multiple processing steps are used for separate fluidic and electrical connections, then each connection can be optimized, but manufacturing productivity decreases and production time increases

Engineering Contradiction:
Improveconnection qualityVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines multiple separate processing steps (fluidic channel formation, electrical contact fabrication, and substrate bonding) into a single integrated bonding operation. The bonding layer is pre-patterned with both fluidic channels and electrical contacts, allowing simultaneous creation of both connection types in one step, thereby improving manufacturing efficiency without compromising connection quality

Inventive Principle:
Principle #5Merging (Combining)

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 manufacturing process, reduces device size and complexity, and enhances performance by shortening electrical paths and eliminating the need for interposer PCBs, while maintaining robust fluidic and electrical connections.

Implementation Method 1

filling the access holes with a conductive material to establish an electrical connection with the first electrical contact

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

bonding the bonding layer with a second substrate having a second electrical contact exposed on a surface thereof

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4596106A1Integrated fluidic-electrical bonding
Publication Date: 2025.08.06 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP4596106A1 patent drawingFigure 1
  • EP4596106A1 patent drawingFigure 2a~2c
  • EP4596106A1 patent drawingFigure 3

AI summary

The present invention relates to a method for integrating a first substrate with a second substrate by establishing an electrical connection between them. The method includes providing a first substrate with an accessible first electrical contact and a bonding layer that is in physical contact with the first substrate's surface. The bonding layer features a patterned fluidic pathway and an access hole that exposes the first electrical contact. The access hole is filled with a conductive material to create an electrical connection to the first electrical contact. Subsequently, the bonding layer is bonded to a second substrate that has a second electrical contact exposed on its surface, such that the conductive material also establishes an electrical connection with the second electrical contact. This integration method facilitates the creation of complex structures with both electrical and fluidic interconnectivity between substrates.