Multilayer Ceramic Electronic Part Corner Electrode Plating Infiltration
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Solution Overview
Problem
Multilayer ceramic electronic parts with thin external electrodes are prone to infiltration of plating solutions due to reduced corner coverage performance, leading to deteriorated moisture resistance reliability, especially in high capacitance devices where low-temperature sintering materials like glass are used.
Innovation Solution
The formation of conductive layers with a higher metal content and lower glass content on the corner portions of external electrodes, positioned outside the active layer, enhances corner coverage performance without increasing the overall thickness of the external electrodes, using conductive metals like copper, nickel, and silver-palladium, and a conductive resin such as epoxy, to prevent plating solution infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If external electrodes are thinned to achieve miniaturization, then the size of the multilayer ceramic electronic part is reduced, but the corner coverage performance deteriorates and plating solution infiltration occurs
Solution Approach 1:
The patent applies different material compositions to different regions of the external electrode. The corner portions contain a higher metal content (70-90 wt%) and lower glass content (10-30 wt%) compared to the center portions (50-70 wt% metal, 30-50 wt% glass). This local differentiation ensures that the vulnerable corner regions have superior coverage and resistance to plating solution infiltration, while the center regions maintain adequate electrical conductivity and adhesion.
2Temperature
If glass with low softening temperature is used to reduce thermal impacts during sintering, then the sintering temperature is reduced, but the acid resistance at plating time deteriorates
Solution Approach 1:
The patent employs a composite material system consisting of multiple glass components with different softening characteristics. The glass composition includes specific ratios of oxides (SiO2, B2O3, Al2O3, etc.) that create a composite structure with both low softening temperature for easy sintering and adequate acid resistance for plating durability. The metal powder and glass form a composite external electrode material that balances thermal and chemical requirements.
3Quantity of substance
If the number of stacked internal electrodes is increased to achieve high capacitance, then the capacitance is increased, but the cover layer thickness is reduced and corner portions become more exposed
Solution Approach 1:
The patent reinforces the corner portions of the external electrodes with a higher metal content composition specifically at these vulnerable locations. Since internal electrodes extend to the corner portions when cover layers are thinned, the enhanced metal-rich composition at the external electrode corners provides superior coverage and protection against plating solution infiltration and moisture penetration, compensating for the reduced cover layer thickness.
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
This solution improves the reliability of multilayer ceramic electronic parts by maintaining the miniaturized size and high capacitance while enhancing moisture resistance and preventing plating solution infiltration, thus ensuring the product's quality and performance.
Implementation Method 1
the metal in the external electrodes is sintered by sintering the ceramic bodies
Implementation Method 2
in the case of glass softened at a relatively low temperature
Data Source
AI summary
There is provided a multilayer ceramic electronic part including: a ceramic body including dielectric layers; an active layer including a plurality of first and second internal electrodes formed to be alternately exposed to both end surfaces of the ceramic body; upper and lower cover layers formed on upper and lower portions of the active layer; and first and second external electrodes formed on both end portions of the ceramic body, wherein the first external electrode includes a first base electrode, a first conductive layer formed on the first base electrode at a corner portion of the ceramic body, and the second external electrode includes a second base electrode, a second conductive layer formed on the second base electrode at a corner portion of the ceramic body, the first and second conductive layers being positioned outside the active layer in a thickness direction of the ceramic body.