Silver Particle Size Distribution for Adhesive Flow and Shape Stability
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Solution Overview
Problem
Conductive adhesives containing silver particles require improved flowability and shape stability during application to ensure precise bonding between electronic components.
Innovation Solution
Adjusting the particle size distribution of silver particles by controlling the SPAN value (V90 - V10)/V50 within a specific range using a photocentrifuge method, with a compound adhered to the silver particles' surface, to enhance flowability and shape stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If silver particles are dispersed in a conductive adhesive, then the adhesive achieves good flowability for application, but the shape stability after application deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution of silver particles, specifically setting the D10 value between 0.5-2.0 μm, D50 value between 2.0-5.0 μm, and D90 value between 5.0-10.0 μm. This optimization of particle size parameters enables the conductive adhesive to achieve both good flowability for application and excellent shape stability after application, resolving the technical contradiction between these two properties.
2Stability of the object's composition
If silver particles with narrow size distribution are used, then shape stability improves, but flowability deteriorates
Solution Approach 1:
The patent implements parameter changes by optimizing the particle size distribution parameters (D10: 0.5-2.0 μm, D50: 2.0-5.0 μm, D90: 5.0-10.0 μm) to achieve a balanced distribution that provides both shape stability and flowability. This controlled parameter range resolves the contradiction between narrow distribution benefits and flowability requirements.
Solution Approach 2:
The patent applies local quality by creating different regions within the particle size distribution - smaller particles (D10 range) that provide flowability and fill voids, medium particles (D50 range) that provide structural stability, and larger particles (D90 range) that maintain shape. This localized functional distribution resolves the contradiction between shape stability and flowability.
3Loss of time
If silver particles are sintered at low temperature, then processing time is reduced, but bonding strength deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution (D10: 0.5-2.0 μm, D50: 2.0-5.0 μm, D90: 5.0-10.0 μm) which enables efficient sintering at low temperatures (90-150°C) while maintaining high bonding strength. The controlled size distribution facilitates rapid heat transfer and uniform sintering, achieving both time reduction and strength maintenance.
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 solution provides silver particles with excellent flowability and shape stability, enabling precise bonding and efficient sintering for electronic parts.
Implementation Method 1
when a sedimentation velocity is expressed by a cumulative distribution, V10 is the sedimentation velocity at a cumulative value of 10%; V90 is the sedimentation velocity at a cumulative value of 90%; and V50 (median sedimentation velocity) is the sedimentation velocity at a cumulative value of 50%
Implementation Method 2
a compound represented by the following formula (1) is adhered to a surface of the silver particles
Implementation Method 3
Silver particles have the property of being easily sintered by a heat treatment at low temperature in a short period of time
Data Source
AI summary
There is provided a conductive adhesive comprising silver particles dispersed in a solvent, the silver particles having good flowability, and excellent shape stability after being applied to a member and before being sintered. Silver particles dispersed in a solvent, in which a compound represented by the following formula (1) is adhered to a surface of the silver particles, wherein R1 is a C1-5 alkyl group, and R2 is a hydrogen atom or a C1-5 alkyl group, and when a concentration of the silver particles in the solvent is 50% by mass, a value of SPAN as measured by a photocentrifuge method under the following conditions is 0.1 or more and 5.0 or less: SPAN:V90−V10/V50 wherein when a sedimentation velocity is expressed by a cumulative distribution, V10 is the sedimentation velocity at a cumulative value of 10%; V90 is the sedimentation velocity at a cumulative value of 90%; and V50 (median sedimentation velocity) is the sedimentation velocity at a cumulative value of 50%.