Fused Silver Conductive Material for Low Resistance Bonding
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Solution Overview
Problem
Conductive materials produced using existing methods have high electric resistance due to non-fused silver particles and rely on resin adhesion, which is unstable and prone to degradation, leading to poor bonding strength and increased resistance over time.
Innovation Solution
A method involving heating a conductive material composition with full-cured or semi-cured thermosetting resin and silver particles to fuse the silver particles, reducing electric resistance and enhancing bonding strength through metal bonding, while using a thermoplastic or semi-cured resin to maintain flexibility and reduce resin content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional conductive paste with thermosetting resin is used to achieve adhesion, then bonding strength is improved, but electric resistance increases and conductivity decreases
Solution Approach 1:
The patent changes the physical state of silver particles from discrete particles to fused state through controlled heating, transforming the conduction mechanism from particle-to-particle contact to continuous metal bonding. This parameter change in the aggregation state of conductive material resolves the contradiction by achieving both adhesion (through resin) and high conductivity (through fused silver)
Solution Approach 2:
The patent creates a composite structure where thermosetting resin provides adhesion and bonding strength while fused silver particles provide electrical conductivity. The composite combines the advantages of both materials: the resin matrix for mechanical strength and the continuous silver phase for electrical conduction, resolving the trade-off between bonding strength and conductivity
2Reliability
If silver particles are made dense through resin curing to allow current flow, then conductivity is improved, but metal bonding does not occur and resistance remains high
Solution Approach 1:
The patent utilizes the phase transition of silver particles from solid discrete particles to fused metallic state through controlled heating below the melting point. This phase transition enables metal bonding between particles, creating continuous conductive paths and achieving both high conductivity and strong metal bonding simultaneously
3Strength
If resin content is increased to improve adhesion and bonding, then bonding strength is improved, but electric resistance increases due to more interstices between metal particles
Solution Approach 1:
The patent changes the state of silver particles from discrete to fused through heating, which eliminates the need for high resin content. The fused silver particles create continuous conductive paths independent of resin matrix density, allowing low resin content to provide both adhesion and high conductivity without the trade-off
4Strength
If conventional conductive adhesive is used for surface mounting, then adhesion to electrodes is improved, but metal particles are not fused and bonding strength decreases over time
Solution Approach 1:
The patent applies controlled heating to induce phase transition and fusion of silver particles, creating strong metal bonds that are durable over time. This thermal processing step transforms the adhesive joint from a purely resin-based connection to a metal-bonded connection, significantly improving long-term bonding durability while maintaining initial adhesion
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 produces conductive materials with significantly lower electric resistance (≤4.0×10^-5 Ω·cm) and improved bonding strength, stability, and flexibility, reducing delamination and resistance variation over time.
Implementation Method 1
heating a conductive material composition to fuse the silver particles
Implementation Method 2
silver particles are fused when heated to a certain temperature
Data Source
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AI summary
The object of the present invention is to provide a method for producing a conductive material that has a low electric resistance and that is obtained using an inexpensive and stable conductive material composition. A conductive material having a low electric resistance can be obtained by a method including the step of heating a conductive material composition that contains at least one of a full-cured or semi-cured thermosetting resin and a thermoplastic resin, as well as silver particles. Such a conductive material is a conductive material that includes fused silver particles, and thermosetting resin fine particles that have an average particle diameter of 0.1 µm to 10 µm both inclusive and are dispersed in the fused silver particles. Further, in such a conductive material is a conductive material that includes fused silver particles, and a thermoplastic resin welded among the fused silver particles.