Silver Powder Surface Modification for Fine-Line Conductive Patterns
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional silver powders used in conductive pastes for electronic components, such as laminated capacitors and plasma display panels, suffer from aggregation issues, making it difficult to form fine-line conductive patterns with high density and low resistance.
Innovation Solution
A silver powder coated with a fatty acid and treated with an aliphatic amine to form an aliphatic amide, which improves the thixotropic ratio and Casson yield value of the conductive paste, enabling the formation of fine-line conductive patterns with low resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If silver powder is produced by conventional wet reduction method, then silver powder can be obtained, but the silver powder is violently aggregated and cannot be applied to fine-line conductive patterns
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance between silver particles to prevent aggregation. The dispersant adsorbs onto the silver particle surfaces and provides steric or electrostatic repulsion, maintaining particle separation and uniform distribution in the conductive paste, thereby enabling fine-line pattern formation without violent aggregation
Solution Approach 2:
The patent modifies the surface properties of silver particles by controlling particle size distribution (D10, D50, D90 parameters) and surface treatment during production. By optimizing these parameters, the silver powder achieves better dispersibility and reduced aggregation tendency, making it suitable for fine-line conductive patterns
2Manufacturing precision
If conductive paste is printed to form thinner lines, then finer conductive patterns can be achieved, but the thixotropic ratio and Casson yield value must be high which is difficult to obtain with conventional silver powder
Solution Approach 1:
The patent optimizes the thixotropic ratio (viscosity at low stirring speed/viscosity at high stirring speed) and Casson yield value of the conductive paste by adjusting silver powder particle size distribution and surface treatment. These parameter changes enable the paste to maintain high viscosity at rest (preventing sagging) while flowing easily during printing, achieving precise fine-line patterns with controlled thickness
3Length of moving object
If silver powder with small particle size is used, then fine-line conductive patterns can be formed, but the silver powder aggregates violently and dispersibility deteriorates
Solution Approach 1:
The patent uses a dispersant as an intermediary substance that adsorbs onto small silver particle surfaces, providing steric or electrostatic repulsion forces that prevent aggregation. This mediator maintains the stability of small particle suspensions, ensuring good dispersibility while retaining the fine particle size necessary for high-density conductive patterns
Solution Approach 2:
The patent creates a composite structure where dispersant molecules are associated with silver particle surfaces, forming a stable colloidal system. This composite approach combines the beneficial small particle size of silver with the stabilizing properties of the dispersant, achieving both fine-line capability and resistance to aggregation
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 treated silver powder produces a conductive paste with enhanced thixotropic ratio and Casson yield value, allowing for the creation of conductive patterns with improved printability and reduced resistance.
Implementation Method 1
allowing the fatty acid to react with the aliphatic amine to form an aliphatic amide between the fatty acid and the aliphatic amine
Implementation Method 2
it is advantageous that the thixotropic ratio (the ratio of viscosity at a low stirring speed to that at a high stirring speed) and Casson yield value of the conductive paste are high
Data Source
AI summary
There is provided a silver powder, which is able to obtain a conductive paste having a high thixotropic ratio and a high Casson yield value and which is able to form a conductive pattern having a low resistance, and a method for producing the same. An aliphatic amine such as hexadecylamine is added to a silver powder, the surface of which is coated with a fatty acid such as stearic acid, to be stirred and mixed to form the aliphatic amine on the outermost surface of the silver powder while allowing the fatty acid to react with the aliphatic amine to form an aliphatic amide such as hexadecanamide between the fatty acid and the aliphatic amine.