Multilayer Ceramic Capacitor External Electrodes with Conductive Resin
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Solution Overview
Problem
Multilayer ceramic electronic components face challenges in miniaturization due to penetration of plating liquid through thin external electrodes, leading to reliability issues and increased equivalent series resistance (ESR), particularly when external electrodes have irregular shapes or insufficient stress absorption.
Innovation Solution
A conductive paste for external electrodes is developed, comprising a metal layer and a conductive resin layer with a copper powder mixture of spherical and flake type particles, where the first copper powder has a particle diameter of 2 μm or greater and the second copper powder has a diameter of 0.7 μm or smaller, with specific weight and area percentages to improve ESR characteristics and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the external electrode is thinned to enable miniaturization, then the size of electronic products is reduced, but plating liquid penetrates through the thin external electrode causing reliability failures
Solution Approach 1:
The patent applies composite materials by forming a multilayer structure consisting of a metal layer and a resin layer. The metal layer provides electrical conductivity while the resin layer prevents plating liquid penetration, creating a composite external electrode that simultaneously achieves miniaturization and maintains reliability.
Solution Approach 2:
The resin layer acts as an intermediary between the metal layer and the plating liquid. It prevents direct contact between the plating liquid and the metal layer, thereby preventing penetration and reliability failures while allowing the external electrode to be thinned for miniaturization.
2Reliability
If a resin composition is coated between the metal layer and plating layer to absorb stress and improve reliability, then reliability is improved, but equivalent series resistance (ESR) increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the thickness of the resin layer and the composition of the conductive paste. By optimizing these parameters, the resin layer provides stress absorption and penetration prevention while minimizing the increase in ESR through precise dimensional and compositional control.
Solution Approach 2:
The patent applies local quality by creating a multilayer structure where different layers have specialized functions. The metal layer provides conductivity, the resin layer provides stress absorption and penetration prevention, and the conductive paste with specific copper powder characteristics provides optimized electrical properties. Each layer is locally optimized for its specific function to balance reliability and ESR.
3Loss of energy
If copper powder with specific particle sizes is used in the conductive resin layer, then ESR characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the copper powder into two distinct size ranges: first copper powder with 0.7 μm or smaller particle diameter and second copper powder with 2 μm or larger particle diameter. This segmentation allows each particle size to fulfill specific roles in optimizing ESR characteristics while maintaining manageable manufacturing processes through defined particle classifications.
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 solution effectively reduces equivalent series resistance and enhances reliability by preventing delamination and improving plating properties, ensuring 0.1 mΩ≦ESR≦30 mΩ in multilayer ceramic capacitors, while maintaining high capacitance and stress absorption capabilities.
Implementation Method 1
the conducive resin layer containing a copper powder and an epoxy resin
Implementation Method 2
a resin composition containing a conductive material is coated between a metal layer of the external electrode and a plating layer, so that external impacts may be absorbed
Data Source
AI summary
There is provided a multilayer ceramic electronic component, including a ceramic body including dielectric layers; a plurality of internal electrodes stacked within the ceramic body, and external electrodes formed on external surfaces of the ceramic body and electrically connected to the internal electrodes, wherein the external electrodes include a metal layer and a conductive resin layer formed on the metal layer, the conducive resin layer containing a copper powder and an epoxy resin, the copper powder including a first copper powder having a content of 10 wt % or more and a particle diameter of 2 μm or greater and a second copper powder having a content of 5 wt % or more and a particle diameter of 0.7 μm or smaller, the first copper powder being a mixture of spherical powder particles and flake type powder particles.