Silver Conductive Paste Composition for Stable Fine-Line Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing conductive pastes face challenges in maintaining viscosity stability during printing, forming accurate conductive wirings and joined structures, and achieving high joining strength with substrates, particularly in inert gas atmospheres like nitrogen, due to issues such as bleeding, uneven printing, and residual non-conductive components.
Innovation Solution
A conductive paste containing silver particles with two different sizes (1 nm to 100 nm and 0.1 µm to 10 µm) coated with a specific amine-based protective agent, and a solvent represented by Formula (I), which maintains viscosity and prevents bleeding, allowing for accurate printing and strong substrate connections even in inert gas atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conductive paste containing adhesive and thickener is used, then printing accuracy is improved, but residual non-conductive components remain after sintering, deteriorating electrical characteristics
Solution Approach 1:
The patent removes adhesive and thickener components from the conductive paste formulation, extracting the harmful non-conductive residues that deteriorate electrical characteristics while maintaining printing accuracy through alternative viscosity control mechanisms
Solution Approach 2:
The patent changes the particle size distribution parameter of silver particles to a specific range (0.1 μm to 15 μm) and adjusts the solvent composition to achieve appropriate viscosity without requiring adhesive or thickener, thereby eliminating residual non-conductive components
2Reliability
If silver particles with average particle size of 0.1 μm or greater are used, then conductivity is improved, but sintering does not proceed in nitrogen atmosphere, making joining difficult
Solution Approach 1:
The patent applies local quality by using a bimodal particle size distribution where larger particles (0.1 μm to 10 μm) provide conductivity while smaller particles (1 nm to 100 nm) facilitate sintering in nitrogen atmosphere, with each size serving a specific functional role in different regions of the paste structure
3Ease of operation
If alcohol solvent is used, then viscosity is reduced for printing, but high volatilization rate causes viscosity fluctuation, making fine pattern formation difficult
Solution Approach 1:
The patent changes the solvent parameter from volatile alcohol to non-volatile or low-volatility solvents (such as glycol ethers or water), eliminating viscosity fluctuation during printing while maintaining appropriate fluidity through optimized solvent composition and particle size control
4Stability of the object's composition
If ethylene glycol is used as solvent, then viscosity stability is improved, but joining strength with substrate is insufficient
Solution Approach 1:
The patent uses composite material strategy by combining silver particles of specific size ranges with optimized solvent composition and optional adhesive components in controlled amounts, creating a composite paste formulation that achieves both viscosity stability and high joining strength through synergistic interactions between components
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 paste achieves highly accurate and strong conductive wirings and joined structures with stable viscosity, preventing deterioration of electrical characteristics and enabling fast sintering at lower temperatures, thus enhancing the quality of electronic components.
Implementation Method 1
sintering fast even in an inert gas atmosphere such as nitrogen
Implementation Method 2
capable of suppressing fluctuations in viscosity at a printing temperature to perform printing without unevenness
Implementation Method 3
silver particles having an average particle size of 1 nm or greater and less than 100 nm and a silver particle (B) having an average particle size of 0.1 μm or greater and 10 μm or less, the silver particles (A) being a silver nanoparticle having a configuration in which a surface is coated with a protective agent containing amine
Data Source
AI summary
An object of the present disclosure is to provide a paste that can suppress fluctuations in viscosity at a printing temperature to perform printing without unevenness, and is sintered fast even in an inert gas atmosphere such as nitrogen to form a highly accurate conductive wiring and a joined structure excellent in joining strength. The present disclosure provides an adhesive conductive paste for forming a conductive wiring and/or a joined structure to connect electronic elements, the adhesive conductive paste including a conductive particle and a solvent. The adhesive conductive paste contains, as the conductive particle, a silver particle (A) having an average particle size of 1 nm or greater and less than 100 nm and a silver particle (B) having an average particle size of 0.1 µm or greater and 10 µm or less, the silver particle (A) being a silver nanoparticle having a configuration in which a surface is coated with a protective agent containing amine, and the adhesive conductive paste contains, as the solvent, a compound (C) represented by Formula (I) below: Ra-O-(X-O)n-Rb ... (I) where in Formula (I), Ra represents a monovalent group selected from a hydrocarbon group having from 1 to 6 carbon atom(s) and an acyl group, X represents a divalent group selected from a hydrocarbon group having from 2 to 6 carbon atoms, Rb represents a hydrogen atom or a monovalent group selected from a hydrocarbon group having from 1 to 6 carbon atom(s) and an acyl group, Ra and Rb may be the same, n represents an integer from 1 to 3.