Conductive Particle Nanosized Protrusions Low-Temperature Sintering
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Solution Overview
Problem
Current methods for forming microstructures in electronic devices, such as optical patterning, are energy-intensive, costly, and environmentally polluting, and existing conductive particles face challenges in achieving high conductivity and reliability, especially with metals like copper and nickel, which oxidize during heat treatment.
Innovation Solution
A conductive particle with nanosized protrusions formed on a metal base particle, created through a process involving seed particles and metal layers, allowing for high conductivity and low-temperature sintering, and can be patterned using solution processes like screen printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal nanoparticles (Cu, Ni) are used to lower melting point and enable low-temperature sintering, then sintering temperature is reduced, but the metal nanoparticles oxidize during heat treatment and sintering behavior is hindered, reducing conductivity
Solution Approach 1:
A core-shell structure is employed where a stable metal core (Au, Ag, Pd) protects the sintering-active metal shell (Cu, Ni). The stable core acts as an intermediary that prevents oxidation of the shell during heat treatment while still allowing the shell to provide sintering behavior at low temperatures, thus resolving the contradiction between low sintering temperature and conductivity reliability
Solution Approach 2:
The conductive particle is designed as a composite structure combining different metals with complementary properties: one metal provides low melting point and sintering activity (Cu, Ni), while another provides oxidation resistance (Au, Ag, Pd). This composite approach allows simultaneous achievement of low sintering temperature and high conductivity reliability
2Reliability
If silver or gold are used as electrode materials to avoid oxidization, then reliability is improved, but cost increases significantly
Solution Approach 1:
The stable, oxidation-resistant metal is localized in the core region while the sintering-active metal forms the outer shell. This local quality distribution allows the expensive stable metal to provide oxidation protection only where needed (at the core), while the cheaper sintering-active metal provides the primary sintering function, reducing overall material cost while maintaining reliability
3Manufacturing precision
If optical patterning method is used to form microstructures, then manufacturing precision is achieved, but energy consumption increases and environmental pollution occurs
Solution Approach 1:
The patent replaces the optical/chemical patterning process with a direct metal deposition and sintering process. Instead of using photoresists, exposure, and etching (optical patterning), the invention uses metal nanoparticles that are directly deposited and sintered to form conductive patterns. This substitution eliminates the need for energy-intensive optical equipment and harmful chemicals, reducing both energy consumption and environmental pollution while maintaining pattern formation capability
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 particle achieves excellent specific resistance characteristics and high adhesivity, enabling the formation of reliable electrodes with low production costs and environmental impact, suitable for various electronic devices.
Implementation Method 1
the melting point of the metal material can be remarkably lowered, thus providing the basis for forming a conductive film for an electrode using low-temperature heat treatment
Data Source
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AI summary
Disclosed herein is a conductive particle, including: a base particle containing a metal; a seed particle formed on a surface of the base particle; and a first metal layer formed on the base particle, wherein the first metal layer includes a protrusion surrounding the seed particle. The conductive particle has excellent specific resistance characteristics when it is sintered because it has nanosized protrusions formed on the surface of a metal base particle.