Low-Temperature Conductive Paste for High-Conductivity Printed Films
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Solution Overview
Problem
Existing methods for forming conductive films in organic semiconductor devices, such as those using gold, are costly and require vacuum apparatuses, while conductive pastes with silver or carbon fillers face issues with conductivity due to point contact between particles.
Innovation Solution
A conductive paste comprising solder powder with a melting point of less than or equal to 120°C, a conductive filler, a flux for oxide film removal, and a non-polar solvent, applied in a ratio of 20% to 80% by mass, which includes a solder alloy and a conductive filler like Cu, Ag, or carbon, allowing for heating to form a conductive film without vacuum apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conductive paste with conductive filler such as silver or carbon is used, then the cost of film formation is reduced and vacuum apparatus is not required, but the conductivity of the conductive film is insufficient due to point contact between particles
Solution Approach 1:
The conductive paste combines multiple materials with different functions: solder powder (for low-temperature melting and particle connection), conductive filler (for conductivity), flux (for oxide removal), and solvent (for paste formation). This composite approach allows the solder to melt and connect conductive particles effectively, resolving the conductivity issue while maintaining cost-effectiveness and avoiding vacuum apparatus requirements
Solution Approach 2:
The invention specifies a melting point parameter for the solder powder (≤120°C) and a mass ratio parameter for conductive filler to solder powder (20%-80%). These parameter controls ensure the solder melts at appropriate temperatures to connect particles without damaging the substrate, while the ratio optimization balances conductivity and paste integrity, resolving the contradiction between ease of manufacture and conductivity
2Reliability
If gold is used for conductive film in organic semiconductor devices, then conductivity and stability are improved, but the cost of materials and processes increases
Solution Approach 1:
The invention replaces expensive gold with cheaper materials: solder powder and conductive filler combinations that provide adequate conductivity and stability for organic semiconductor devices. The use of low-cost solder alloys (melting point ≤120°C) and common conductive fillers (silver, carbon) dramatically reduces material costs while maintaining functional performance
Solution Approach 2:
Instead of using pure gold, the invention employs a composite conductive paste containing solder powder, conductive filler, flux, and solvent. This composite approach achieves comparable conductivity and stability to gold at a fraction of the cost, while the low melting point of the solder enables processing without expensive vacuum apparatus
3Manufacturing precision
If a vacuum apparatus is used for forming gold film, then film quality and uniformity are improved, but the device complexity and process difficulty increase
Solution Approach 1:
The invention replaces the complex mechanical vacuum deposition system with a simpler thermal processing approach. The conductive paste is applied using conventional printing or coating methods, then heated to melt the solder powder (≤120°C), which automatically connects particles and forms uniform conductive films without requiring vacuum apparatus or complex mechanical systems
Solution Approach 2:
The invention exploits the phase transition of solder powder from solid to liquid at its melting point (≤120°C). During heating, the solder melts and flows to connect conductive particles, forming continuous conductive paths. This self-organizing phase transition process naturally produces uniform films without requiring vacuum apparatus or complex process control
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 effectively forms films with improved conductivity by ensuring solder enters between conductive particles, maintaining the integrity of organic semiconductor devices and avoiding chemical or physical damage, with low resistance values achievable through controlled heating.
Implementation Method 1
a solder powder having a melting point of less than or equal to 120° C.
Implementation Method 2
a flux for removing an oxide film of the solder powder
Implementation Method 3
heating and cured to form a conductive film
Data Source
AI summary
A conductive paste includes: a solder powder having a melting point of less than or equal to 120° C.; a conductive filler; a flux for removing an oxide film of the solder powder; and a solvent, wherein a ratio of a mass of the conductive filler to a mass of the solder powder is 20% to 80%.