Flip-Chip Microfluidic Adhesive Bonding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing microfluidic systems face challenges in achieving simultaneous and secure fluidic and electrical connections with semiconductor components, often requiring complex multi-step processes and materials that may not ensure reliable sealing or functional integrity.

Innovation Solution

A method utilizing a two-stage adhesive process in the flip-chip connection method, where a fluidically sealing adhesive is applied first, followed by an electrically conductive adhesive, allowing for precise and secure fluidic and electrical contacting by curing the adhesives sequentially under defined contact pressure, preventing short circuits and ensuring reliable connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single adhesive is used for both fluidic sealing and electrical connection, then the manufacturing process is simplified, but reliable simultaneous sealing and functional integrity cannot be ensured

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidsealing and functional integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The adhesive application process is segmented into two distinct stages: first applying a fluidically sealing adhesive for tight sealing, then applying a second electrically conductive adhesive for electrical connection. This segmentation allows each adhesive to be optimized for its specific function, ensuring both reliable sealing and functional integrity without compromising manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different adhesive properties are applied to different locations on the connecting surface. The fluidically sealing adhesive is applied in areas requiring tight sealing, while the electrically conductive adhesive is applied in areas requiring electrical contact. This local differentiation ensures that each region of the connection serves its specific function effectively.

Inventive Principle:
Principle #3Local quality

2Productivity

If adhesive application order is not optimized, then both fluidic and electrical connections can be made simultaneously, but short circuits may occur due to improper curing sequence

Engineering Contradiction:
Improveconnection efficiencyVSAvoidshort circuit risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The fluidically sealing adhesive is applied and cured first to establish a secure, short-circuit-proof seal between the substrates. Only after this preliminary sealing action is complete is the second electrically conductive adhesive applied. This preliminary action prevents short circuits by ensuring the fluidic pathway is sealed before electrical contacts are established.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The first adhesive serves as a protective cushioning layer that prevents direct contact between conductive elements before the second adhesive is applied. This beforehand cushioning measures protects against potential short circuits by maintaining electrical isolation during the assembly process.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If complex multi-step processes are used for connection, then reliable sealing and functional integrity can be achieved, but manufacturing complexity and time increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The method merges fluidic sealing and electrical connection into a single integrated adhesive application process. By applying both adhesives in sequence during one manufacturing step, the process achieves reliable sealing and functional integrity without requiring separate assembly operations, thereby reducing overall process complexity while maintaining high reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connecting surface serves multiple functions simultaneously: it provides both fluidic sealing and electrical connection pathways. The dual-adhesive approach enables this multi-functionality by creating distinct but integrated zones for sealing and conduction on the same interface, reducing the need for separate components or processes.

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

This approach enables secure, electrically functional, and fluidically tight connections between microfluidic and electronic substrates, facilitating the integration of semiconductor chips with microfluidic systems while preventing short circuits and ensuring reliable performance.

Implementation Method 1

application of a fluidically sealing adhesive (5) to produce a fluidic contact to the connecting surface of the microfluidic substrate and/or the electronic substrate

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

application of a second adhesive (6) for electrical connection to the connecting surface of the microfluidic substrate and/or the electronic substrate

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

curing of the first and second adhesive, the second adhesive curing first

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Data Source

PatentEP2590891B1Method for producing an integrated microfluidic system
Publication Date: 2016.03.02 ROBERT BOSCH GMBH
  • EP2590891B1 patent drawingFigure 1~2
  • EP2590891B1 patent drawingFigure 3a~3c
  • EP2590891B1 patent drawingFigure 4a~4b

AI summary

The invention relates to the production of an integrated microfluidic system and to the integrated microfluidic system as such. An electronics substrate, especially a semiconductor chip, is connected to a microfluidic substrate in a flip-chip configuration. For this purpose, the fluidic connecting elements of the two substrates to be interconnected are interconnected by a first adhesive and the electrical contacts of the two substrates are interconnected by a second adhesive. The adhesives are cured, the second adhesive curing first.