Silver Paste for High-Temperature Electronic Connections
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Solution Overview
Problem
Existing methods for joining electronic components require high pressure and temperature, which can be detrimental to component reliability and are difficult to apply over large surfaces, especially when the operating temperature exceeds 250°C, and they often result in embrittlement due to intermetallic phase formation.
Innovation Solution
A method using easily decomposable silver compounds, such as silver oxide or silver carbonate, which convert to elemental silver at temperatures below 300°C, allowing for a strong, conductive connection under atmospheric pressure, reducing the need for high-pressure sintering and minimizing the risk of embrittlement, and can be applied as a paste to large surfaces using techniques like stencil printing or spraying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high pressure and temperature are used for joining electronic components, then strong connections are achieved, but components with operating temperatures above 250°C cannot be reliably joined
Solution Approach 1:
The patent changes the chemical composition parameters of the contacting paste by incorporating silver lactate and copper particles in specific ratios, allowing the paste to form intermetallic phases that remain stable at high operating temperatures above 250°C, thus resolving the contradiction between connection strength and high-temperature reliability
Solution Approach 2:
The patent creates a composite paste formulation combining silver lactate, copper particles, and organic vehicle, which produces a multi-phase sintered layer containing both metallic silver and copper-silver intermetallic compounds, achieving both strong bonding and high-temperature stability through material composition rather than extreme processing conditions
2Reliability
If high pressure is applied during sintering, then good contact is achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent modifies the paste composition to include copper particles and silver lactate in optimized ratios, enabling the material to achieve reliable electrical and thermal contact at reduced pressures through enhanced conductivity pathways and controlled intermetallic phase formation during sintering
Solution Approach 2:
The patent creates local variations in material properties within the paste by incorporating copper particles of specific size ranges and silver lactate concentrations, which form conductive networks and intermetallic phases at specific locations during sintering, achieving reliable contact without requiring uniformly high pressure across the entire contact area
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 provides reliable electrical and thermal connections resistant to temperature changes, with improved mechanical strength and reduced porosity, outperforming traditional soft solder alloys and conductive adhesives in terms of thermal shock resistance and longevity, while being easier to produce and store than nanosilver.
Implementation Method 1
easily decomposable silver compounds, such as silver oxide or silver carbonate, which convert to elemental silver at temperatures below 300°C
Implementation Method 2
incorporation of copper or silver particles in a gel-based paste for enhanced conductivity and reliability
Implementation Method 3
contacting pastes made from silver flakes (silver flakes) dispersed in solvent are sintered under pressure of the order of 30 MPa at temperatures of around 300°C
Data Source
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AI summary
According to the invention, to produce an electrically conductive or thermally conductive connection for contacting two elements, elemental metal, particularly silver, is formed between the contact surfaces from a metal compound, in particular a silver compound. According to the invention, the process temperature can be reduced below 240°C when using a silver solder, and the process pressure can be lowered to atmospheric pressure. A contacting paste according to the invention comprises a metal compound, in particular a silver compound, which decomposes below 400°C to form elemental silver. According to the invention, metal is generated in situ from a chemical compound to produce a contact that is usable above the temperature required for its production.