Conductive Paste for Fine Pattern Printing
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Solution Overview
Problem
Current conductive pastes used in screen printing for electronic devices suffer from poor thixotropic index and printing characteristics, leading to widened linewidths and blurring issues, making it difficult to form fine patterns with good precision.
Innovation Solution
A conductive paste composition including epoxy resin, solvent, latent curing agent, flaky metal powder surface-treated with saturated and unsaturated fatty acids, which improves printing characteristics and enables the formation of precise, high-conductivity patterns by optimizing the ratio and properties of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If screen printing method is used to fabricate conductive wiring, then the conductive paste can be applied to form wiring patterns, but the linewidth becomes wider than the target linewidth and edges become blurred
Solution Approach 1:
The patent modifies the rheological parameters of the conductive paste by adjusting viscosity and thixotropic index through specific binder compositions and particle size distributions. This enables the paste to maintain shape fidelity during screen printing while achieving target linewidth precision down to 150 μm without edge blurring
Solution Approach 2:
The patent employs dynamic rheological properties where the paste exhibits shear-thinning behavior during printing (reducing viscosity under shear stress for easy flow through the screen) and rapid viscosity recovery after printing (maintaining sharp edges and preventing spreading). This dynamic response allows precise linewidth control while maintaining printing ease
2Manufacturing precision
If conventional conductive paste is used, then the paste can be printed, but the thixotropic index and printing characteristics are poor causing dripping and inability to form fine patterns
Solution Approach 1:
The patent optimizes the thixotropic index by controlling the particle size distribution (D10, D50, D90 values) and binder composition. The specific combination of metal powder particles with controlled size ranges and organic binder ratios creates a paste that resists dripping while maintaining printability, enabling fine pattern formation with high reliability
Solution Approach 2:
The patent uses a composite paste formulation combining metal powders (silver, copper, or alloys) with specifically selected organic binders and solvents. This composite structure provides both the electrical conductivity needed for functional performance and the rheological properties required for precise screen printing and fine pattern formation without dripping
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 conductive paste achieves improved printing characteristics and high conductivity, allowing for the precise formation of fine patterns with better surface hardness and adhesion, addressing the limitations of existing pastes.
Implementation Method 1
a flaky metal powder surface-treated by saturated fatty acid, and a flaky metal powder surface-treated by unsaturated fatty acid
Data Source
AI summary
A conductive paste is provided, which includes 3 wt % to 20 wt % of epoxy resin, 10 wt % to 25 wt % of solvent, 0.3 wt % to 5 wt % of latent curing agent, 3.5 wt % to 35 wt % of flaky metal powder surface-treated by saturated fatty acid, and 35 wt % to 75 wt % of flaky metal powder surface-treated by unsaturated fatty acid.