Metallic Particle Paste Uniform Dispersion High-Temperature Stability
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Solution Overview
Problem
Conventional metallic particle pastes used for high-temperature bonding in electronic devices suffer from metal diffusion and void aggregation, leading to structural deterioration due to the difficulty in uniformly dispersing a second element in the grain boundary phase, which is essential for stabilizing the bonding material.
Innovation Solution
A metallic particle paste is developed where a second metal is dissolved in a polar solvent, allowing it to be uniformly precipitated on the surface of the first metal particles during curing, inhibiting metal diffusion and reducing void aggregation by forming a stable matrix with improved electrical and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fine particles of the second metal are mixed with fine particles of the first metal to uniformly disperse the second element in the grain boundary phase, then the structural stability at high temperature is improved, but the particles aggregate to form secondary particles making uniform dispersion difficult
Solution Approach 1:
The patent uses an organic compound as an intermediary substance to cover the surface of the second metal particles. This organic compound prevents direct aggregation between metal particles while allowing uniform dispersion in the paste. During curing, the organic compound decomposes and the second metal particles are released in a uniformly dispersed state at the grain boundaries, achieving both uniform dispersion and structural stability.
Solution Approach 2:
The patent applies preliminary action by pre-coating the second metal particles with an organic compound before mixing with the first metal particles. This pre-coating prevents aggregation during storage and application, ensuring that when the paste is cured, the second metal particles remain uniformly dispersed. The preliminary coating action solves the aggregation problem before the actual bonding process occurs.
2Reliability
If a second element is dispersed in the grain boundary phase to stabilize the structure by pinning effect, then the resistance to metal diffusion is improved, but the difficulty in achieving uniform dispersion increases
Solution Approach 1:
The organic compound serves as a mediator that enables easy manufacture of uniformly dispersed paste. It coats the second metal particles, preventing aggregation during handling and application. Upon curing, the organic compound decomposes, releasing the second metal particles in a uniformly dispersed state at the grain boundaries, thereby achieving both ease of manufacture and reliable diffusion resistance.
Solution Approach 2:
The patent changes the physical state and surface properties of the second metal particles by coating them with an organic compound. This parameter change (surface coating) transforms the particles from a state prone to aggregation to a state of stable suspension, enabling easy and uniform dispersion in the paste while maintaining the intended pinning effect at grain boundaries.
3Temperature
If conventional metallic particle paste is used for high-temperature bonding, then the bonding capability at high temperature is achieved, but metal diffusion progresses and fine voids aggregate leading to structural deterioration
Solution Approach 1:
The patent creates a composite material system consisting of first metal particles, second metal particles covered with organic compound, and paste components. The second metal particles act as grain boundary modifiers that pin the grain structure and prevent metal diffusion during high-temperature bonding. The composite structure maintains structural integrity by preventing void aggregation and metal diffusion even at high temperatures.
Solution Approach 2:
The organic compound coating on the second metal particles serves as a temporary intermediary that protects the particles from aggregation during paste formulation and application. During high-temperature curing, this intermediary decomposes and releases the second metal particles, which then stabilize the grain boundaries and prevent structural deterioration during subsequent high-temperature service.
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 results in a stable bonding structure with enhanced thermal stability and reduced void aggregation, maintaining the integrity of the bonding material even at high temperatures.
Implementation Method 1
a second metal different from the first metal is dissolved in the polar solvent, wherein the second metal is uniformly precipitated on a surface of the first metal particles
Implementation Method 2
sinter-bonding metallic particles are candidate of the high thermostability bonding material, that is cured by heat or electromagnetic waves
Implementation Method 3
when the product is left to stand at the curing temperature or in high-temperature environments, the diffusion of metal in the bonding portion is progressed
Data Source
AI summary
According to one embodiment, a metallic particle paste includes a polar solvent and particles dispersed in the polar solvent and containing a first metal. A second metal different from the first metal is dissolved in the polar solvent.