Mixed Silver Powder Conductive Paste Line Precision Coagulation
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Solution Overview
Problem
Conventional spherical silver powders face challenges in achieving optimal particle size distribution, dispersibility, and surface treatment, leading to issues with conductor pattern densification, line precision, and coagulation over time in conductive pastes used for electronic components like solar cells.
Innovation Solution
Mixed silver powders with two or more types of spherical silver powders having different particle size distributions and surface treatment agents are used, with specific particle size and specific gravity control, to enhance dispersibility and prevent coagulation, resulting in a conductive paste with improved conductivity and long-term reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If silver powder with small particle size and narrow distribution is used, then dispersibility and line precision improve, but coagulation during kneading increases and viscosity control becomes difficult
Solution Approach 1:
The invention segments the silver powder population into multiple particle size ranges (first range: 0.5-2.0 μm, second range: 2.0-5.0 μm) with controlled distributions. This segmentation allows small particles to provide precision while larger particles provide structural stability and reduce coagulation, resolving the contradiction between line precision and coagulation resistance.
Solution Approach 2:
The invention creates a composite powder system combining silver particles of different sizes with surface treatments (organic compounds or metal oxides). This composite approach enables the system to exhibit both the precision benefits of fine particles and the stability benefits of larger particles, while surface treatments further prevent coagulation.
2Manufacturing precision
If silver powder with high dispersibility is used, then coating quality improves, but fillability decreases due to voids from coagulated particles
Solution Approach 1:
The invention applies local quality by assigning different particle size functions to different size ranges: smaller particles (0.5-2.0 μm) are optimized for coating quality and dispersibility, while larger particles (2.0-5.0 μm) are optimized for fillability and reducing voids. The surface treatment is selectively applied to enhance local dispersibility without compromising overall packing density.
3Manufacturing precision
If spherical silver powder with controlled particle size is used, then sintering uniformity improves, but surface treatment effectiveness decreases
Solution Approach 1:
The invention applies preliminary action by performing surface treatment on the spherical silver particles before final paste formulation. The surface treatment with organic compounds or metal oxides is applied to the spherical particles to create a protective layer that maintains sintering uniformity while providing long-term stability and preventing coagulation during storage and processing.
Data Source
AI summary
A mixed silver powder and a conductive paste comprising the powder are disclosed. The mixed silver powder is obtained by mixing two or more spherical silver powders having different properties from each other. The mixed powder may minimize the disadvantages of the respective types of the two or more powders and maximize the advantages thereof, thereby improving the characteristics of products. In addition, by comprehensively controlling the particle size distribution of surface-treated mixed silver powder and the particle diameter and specific gravity of primary particles, a high-density conductor pattern, a precise line pattern, and the suppression of aggregation over time can be simultaneously achieved.