Silver Sintering Composition Using Agglomerated Nanoparticles
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Solution Overview
Problem
Existing silver-based sintering materials face challenges such as high porosity, contamination, and the need for large amounts of material due to additives, which can lead to void formation and decreased reliability in joining components, especially under low-pressure conditions.
Innovation Solution
A composition comprising a silver precursor and agglomerated silver nanoparticles with a weight ratio of ≤0.25, allowing for the formation of contamination-free, low-porosity silver sintering layers with high silver content, achieved through a silver precursor of specific formula and agglomerated nanoparticles that sinter at relatively low temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silver-organic complexes are used as sintering material, then low sintering temperature (200-300°C) is achieved, but high porosity and contamination occur due to additive decomposition
Solution Approach 1:
The patent extracts and removes harmful additives from the sintering material composition, using only silver nanoparticles and silver precursor without additional organic additives. This elimination of additives prevents decomposition products and gas formation, thereby avoiding porosity and contamination while maintaining low sintering temperature capability
Solution Approach 2:
The patent changes the chemical composition parameters by using specific silver precursors (silver carboxylates, silver alkoxides, or silver acetates) with defined molecular structures and controlled nanoparticle sizes (5-50 nm). These parameter changes enable the silver organic complex to decompose cleanly without forming harmful residues, resolving the contradiction between low temperature sintering and joint reliability
2Ease of operation
If traditional sintering paste with additives is used, then ease of application is improved, but void formation and contamination increase
Solution Approach 1:
The patent removes traditional paste additives and binders that cause void formation during decomposition. The simplified composition of silver nanoparticles and precursor maintains ease of application through proper dispersion and rheological properties while eliminating the source of harmful decomposition products
Solution Approach 2:
The patent creates an inert environment by using silver nanoparticles and precursors that decompose without forming reactive or harmful gases. The decomposition products are primarily volatile organic compounds that do not create voids or contamination, effectively providing a clean sintering environment
3Quantity of substance
If high amount of silver precursor is used, then complete silver layer formation is achieved, but material usage efficiency decreases
Solution Approach 1:
The patent performs preliminary action by pre-forming silver nanoparticles before the sintering process. These pre-formed nanoparticles serve as nucleation sites that reduce the amount of precursor needed for complete silver layer formation, improving material efficiency while ensuring complete coverage
Solution Approach 2:
The patent optimizes the ratio of silver precursor to silver nanoparticles and controls nanoparticle size (5-50 nm) to maximize the efficiency of silver deposition. This parameter optimization ensures complete silver layer formation with minimal material usage by enhancing the decomposition efficiency and silver release kinetics
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 enables efficient, contamination-free silver sintering with reduced void formation and increased density, facilitating reliable joining of components under mild heat and pressure conditions, while minimizing material usage and maintaining high silver content.
Implementation Method 1
silver-organic complexes that provide silver particles in the nanometer range are commonly used to alleviate these issues
Implementation Method 2
Subsequent heat treatment to join the components may be performed at ambient or elevated pressure
Implementation Method 3
Due to a phenomenon known as size-dependent melting point depression, silver particles in the lower nanometer range have significantly lower melting temperatures than the respective bulk material
Data Source
AI summary
The present invention relates to a composition that is suitable for joining two components by sintering. The composition comprises an organic silver precursor as defined herein and particles that have an average size of ≤20 μm and that comprise agglomerated silver nanoparticles. The ratio of the weight of the silver precursor to the weight of the particles is ≤0.25.