Silver-Copper Conductive Paste for Low-Temperature Power Packaging
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Solution Overview
Problem
Existing packaging materials for power devices, particularly those using silicon carbide and gallium nitride, face high costs and performance issues due to high-temperature sintering, which causes physical damage and the formation of intermetallic compounds, and water-based solvents are not suitable for large-scale industrial application.
Innovation Solution
A silver-copper composite conductive paste comprising micro-copper particles, nano-silver sheets, and nano-silver particles, along with an organic carrier, is formulated and sintered at low temperatures (180-250°C) to improve thermal and electrical conductivity while reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional high-temperature sintering is used for packaging materials, then the thermal conductivity and structural stability are improved, but the substrate devices suffer physical damage and intermetallic compounds form
Solution Approach 1:
The patent changes the sintering temperature parameter from traditional high temperature to low temperature (180-250°C), and modifies the paste composition by using organic carrier solvents instead of water-based solvents, enabling low-temperature sintering that avoids damage to substrate devices while maintaining packaging material performance
Solution Approach 2:
The patent uses a composite paste formulation containing silver particles, copper particles, and organic carrier solvents, creating a multi-component material system that enables low-temperature sintering while achieving the required thermal and electrical conductivity for power device packaging
2Temperature
If nano-silver is used to achieve low-temperature sintering, then the sintering temperature is reduced, but the cost increases excessively
Solution Approach 1:
The patent creates a composite conductive paste containing both silver particles and copper particles, where copper serves as a cost-effective alternative to silver. This composite approach reduces the overall material cost while maintaining electrical conductivity and enabling low-temperature sintering through the organic carrier system
Solution Approach 2:
The patent replaces expensive nano-silver with a combination of silver and copper particles in an organic carrier system, using more economical materials that achieve the same low-temperature sintering effect without the excessive cost associated with pure nano-silver formulations
3Ease of manufacture
If water-based solvents are used in the paste, then the paste can be processed easily, but the solvents volatilize easily which is not beneficial for large-scale industrial application
Solution Approach 1:
The patent changes the carrier solvent from water-based to organic-based solvents with higher boiling points, modifying the volatility parameter to reduce evaporation during processing and storage, thereby improving suitability for large-scale industrial application while maintaining paste processability
Solution Approach 2:
The patent uses organic carrier solvents that are more stable and less prone to volatilization compared to water-based solvents, providing a more reliable and industrially suitable paste formulation that maintains ease of manufacture while enabling large-scale production
4Quantity of substance
If copper powder is added to reduce cost, then the paste cost decreases, but the proportion of copper must be small to maintain performance
Solution Approach 1:
The patent creates a composite paste with optimized ratios of silver particles, copper particles, and organic carrier, where the synergistic combination allows higher copper content for cost reduction while the silver component and organic binder maintain electrical conductivity and overall performance reliability
Solution Approach 2:
The patent applies different material properties to different components: silver particles provide electrical conductivity, copper particles provide cost reduction and thermal conductivity, and the organic carrier provides binding and processability. This local optimization of material functions allows cost reduction without sacrificing overall reliability
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 paste achieves improved thermal and electrical conductivity with reduced costs, suitable for chip packaging and connecting materials in power semiconductor devices, and avoids the drawbacks of high-temperature sintering.
Implementation Method 1
the requirements for packaging materials are higher than the requirements of traditional semiconductor devices or integrated circuits, and packaging materials for power devices should have a good thermal conductivity. At present, traditional packaging materials are sintered at a high temperature, which will inevitably cause some physical damage to substrate devices. Nano-silver particles not only can realize low-temperature sintering
Implementation Method 2
packaging materials for power devices should have a good thermal conductivity
Implementation Method 3
The composite paste achieves improved thermal and electrical conductivity
Data Source
AI summary
The invention belongs to the technical field of packaging interface materials for electronic power devices, and particularly discloses a silver-copper composite conductive paste capable of being sintered at a low temperature, and a preparation method and use thereof. A first purpose of the invention is to provide a silver-copper composite conductive paste capable of being sintered at a low temperature, comprising, by weight, the following components: 20-80% of micro-copper particles; 10-60% of nano-silver sheets; 1-20% of nano-silver particles; and 10% of an organic carrier. The silver-copper composite conductive paste capable of being sintered at a low temperature provided by the invention adopts silver and copper of different sizes and morphologies, large-sized sliver sheets and micro-copper particles are used as skeletons, and small nano-silver particles are used for filling, such that gaps are reduced, and the performance is improved.