Functional Material Mitigating Kirkendall Voids via Multi-Melting Point Particles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming three-dimensional circuit configurations and electronic device components often result in voids and cracks due to Kirkendall voids, which degrade electrical conductivity and reliability, and fail to provide a material that melts at a low temperature but solidifies with a higher melting point.
Innovation Solution
A functional material comprising a combination of first, second, and third metal composite particles with different melting points, dispersed in a fluid medium, which mitigates interdiffusion asymmetry and prevents Kirkendall voids, forming a nanocomposite structure suitable for wiring, electrodes, sealing, or bonding, and allowing the melting point to increase after solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional conductive materials with binder and crosslinking agent are used in via holes, then adhesion and structural integrity are improved, but electrical conductivity deteriorates due to polymeric network coexisting with metal network
Solution Approach 1:
The patent removes the binder and crosslinking agent from the conductive material composition, using only metal particles and metal powder without organic constituents. This extraction of harmful organic components eliminates the polymeric network that degrades electrical conductivity while maintaining adhesion through metal-to-substrate bonding
Solution Approach 2:
The patent creates a composite material system consisting of metal particles (5-50 μm) and metal powder (0.1-5 μm) in specific weight ratios, forming a nanocomposite structure that achieves both strong adhesion and high electrical conductivity without organic binders
2Reliability
If metal diffusion bonding is performed to form conductive structures, then electrical conductivity is improved, but Kirkendall voids and cracks form due to asymmetric interdiffusion
Solution Approach 1:
The patent applies different metal components with specific melting points in different regions and proportions to control diffusion behavior locally. By using metal particles with melting points 100-500°C and metal powder with melting points 500-1000°C in specific weight ratios, the diffusion rate is controlled to prevent asymmetric interdiffusion and Kirkendall void formation
Solution Approach 2:
The patent changes the melting point parameter by selecting specific metal compositions for particles and powder, creating a temperature gradient during bonding that controls diffusion asymmetry. This parameter control prevents void formation while maintaining electrical conductivity
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 material enables the formation of void-free and high-reliability electronic device components with improved electrical conductivity and mechanical strength, maintaining high performance at elevated temperatures.
Implementation Method 1
a first metal composite particles, second metal composite particles and third metal composite particles which are different in composition from one another so that melting points T1(°C), T2(°C) and T3(°C) satisfy a relationship of T1>T2>T3
Implementation Method 2
the asymmetry of interdiffusion, accumulate without disappearing
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A functional material includes at least two kinds of particles selected from the group consisting of first metal composite particles, second metal composite particles and third metal composite particles. The first metal composite particles, the second metal composite particles and the third metal composite particles each contain two or more kinds of metal components. The melting point T1(°C) of the first metal composite particles, the melting point T2(°C) of the second metal composite particles and the melting point T3(°C) of the third metal composite particles satisfy a relationship of T1>T2>T3.