Composite Silver Nanoparticles Low-Temperature Metalization
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Solution Overview
Problem
Conventional composite silver nanoparticles have high metalization temperatures, making them unsuitable as low-temperature substitutes for Pb-Sn solder, and their organic coating layers often result in high decomposition temperatures, leading to poor electrical and thermal conductivity due to polycrystalline silver cores and large particle sizes.
Innovation Solution
Developing composite silver nanoparticles with an organic coating layer composed of alcohol molecules with a carbon number of 1-12, which reduces metalization temperature below 200°C, enhances silver core weight ratio, and ensures high electrical and thermal conductivity by forming single-crystalline silver cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional composite silver nanoparticles with organic coating layers are used, then the organic coating provides stability and dispersibility, but the decomposition temperature becomes high (above 200°C) resulting in poor electrical and thermal conductivity
Solution Approach 1:
The patent changes the chemical composition parameters of the organic coating layer by selecting specific compounds with lower decomposition temperatures. The organic coating is formed from compounds decomposing at 150-200°C, replacing conventional high-decomposition coatings, thereby enabling metalization at lower temperatures while maintaining conductivity requirements
Solution Approach 2:
The patent creates a composite nanoparticle structure with a silver core and a specifically designed organic coating layer. The composite structure combines the high conductivity of silver with an organic coating that decomposes at controlled low temperatures, achieving both stability during handling and low-temperature metalization capability
2Temperature
If the metalization temperature is reduced below 200°C for low-temperature soldering applications, then the resin substrate is protected from damage, but the electrical and thermal conductivity deteriorates due to polycrystalline silver cores
Solution Approach 1:
The patent controls the particle size parameter of the silver core to be 1-10 nm, which is small enough to enable low-temperature sintering and metalization below 200°C. This size parameter change allows the formation of continuous conductive paths at low temperatures while maintaining adequate conductivity through proper particle packing and contact
3Ease of manufacture
If solid silver organic compound is heated without solvent to produce composite silver nanoparticles, then the production process is simplified, but the nanoparticles aggregate into large second particles forming a dumpling state
Solution Approach 1:
The patent introduces an organic solvent as an intermediary medium during the nanoparticle formation process. The solvent prevents direct contact and aggregation between silver nanoparticles during synthesis, enabling them to form and disperse individually. After formation, the solvent can be removed, leaving well-dispersed nanoparticles without dumpling aggregation
Solution Approach 2:
The patent uses an inert organic solvent environment during nanoparticle formation to prevent unwanted oxidation and aggregation reactions. The inert atmosphere provided by the solvent protects the freshly formed silver nanoparticles from interacting with each other and from atmospheric contaminants, maintaining their individuality and preventing dumpling state formation
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 composite silver nanoparticles achieve low-temperature metalization, improved conductivity, and environmental safety, making them suitable for electronic component bonding and semiconductor applications.
Implementation Method 1
the organic coating layer composed of alcohol molecules with a carbon number of 1-12, which reduces metalization temperature below 200°C
Implementation Method 2
heating said alcohol solution in a reaction chamber at a predetermined generation temperature PT for a predetermined generation time, forming a silver core with an average particle diameter of 1 to 20nm through reducing of said silver salt microparticles by said alcohol solvent
Data Source
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AI summary
A cold formation method of composite silver nanoparticles has been established. Thus, provided are composite silver nanoparticles comprising a silver core, which is made up of aggregated silver atoms and has an average particle diameter of from 1 to 20nm, and an organic coating layer formed thereon which comprises at least one member selected from an alcohol molecule derivative having 1 to 12 carbon atoms, an alcohol molecule residue or an alcohol molecule; a composite silver nanopaste which contains at least the composite silver nanoparticles and a solvent and/or a viscosity grant agent added thereto; a method of producing the same; an apparatus for producing the same; a method of bonding the same; and a method of patterning the same. The method of producing the composite silver nanoparticles comprising mixing silver salt microparticles with an alcohol solvent in excess to prepare an excess alcoholic solution, reacting the solution in a reaction chamber for a predetermined period of time at a predetermined temperature, and thus forming silver cores from the silver salt at a low temperature by the reducing effect of the alcohol and also forming an organic coating layer derived from the above-described alcohol around the silver cores.