Curved Internal Electrodes for Multilayer Ceramic Capacitors
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Solution Overview
Problem
In miniaturized array-type multilayer ceramic capacitors, the breakdown voltage (BDV) characteristics are deteriorated due to electric field concentration at the edges of internal electrodes, leading to potential short circuits and decreased capacitance, especially as the number of laminations increases and dielectric layer thickness decreases.
Innovation Solution
The solution involves controlling the size of the gap between internal electrode edges by curving them, ensuring a narrowest gap (Gmin) of 10 μm to 60 μm and a width ratio (Wa/Wb) of 1.1 to 1.35, which prevents electric field focusing and improves BDV characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of laminations is increased and dielectric layer thickness is decreased to achieve miniaturization and high capacitance, then capacitance is improved, but breakdown voltage characteristics deteriorate due to electric field concentration at internal electrode edges
Solution Approach 1:
The internal electrode edges are formed with a curved shape instead of sharp corners. The curvature radius R is controlled to satisfy 1 μm ≤ R ≤ 10 μm, which prevents electric field concentration at the edges. This curved configuration reduces the risk of breakdown while maintaining the high capacitance achieved through increased laminations and reduced dielectric thickness.
Solution Approach 2:
The electrode structure is designed with different properties at different locations: the central portion maintains standard electrode characteristics for capacitance formation, while the edge portions are specifically modified with curvature to address breakdown voltage issues. This localized differentiation allows simultaneous optimization of both capacitance and reliability.
2Quantity of substance
If the gap between adjacent internal electrodes is reduced to increase capacitance density, then capacitance is improved, but electric field concentration increases leading to deteriorated breakdown voltage characteristics
Solution Approach 1:
By curving the internal electrode edges with a controlled radius (1 μm ≤ R ≤ 10 μm), the electric field distribution in the gap between adjacent electrodes is optimized. The curved edges prevent field concentration even when the gap is minimized for high capacitance density, thereby maintaining reliable breakdown voltage characteristics.
3Ease of manufacture
If internal electrode edges are formed with sharp corners to simplify manufacturing, then manufacturing ease is improved, but electric field concentration occurs leading to deteriorated breakdown voltage characteristics
Solution Approach 1:
The manufacturing process incorporates edge curvature formation with radius 1 μm ≤ R ≤ 10 μm, which can be achieved through standard printing and sintering techniques. This curved edge design prevents electric field concentration and breakdown while remaining compatible with existing manufacturing processes, thus maintaining ease of manufacture.
4Volume of moving object
If the dielectric layer thickness is decreased to achieve miniaturization, then device size is reduced, but electric field strength increases leading to deteriorated breakdown voltage characteristics
Solution Approach 1:
The curved internal electrode edges (curvature radius 1 μm ≤ R ≤ 10 μm) distribute the electric field more evenly across the thinned dielectric layer. This prevents field concentration points that would cause premature breakdown, enabling safe miniaturization with reduced dielectric thickness while maintaining reliable breakdown voltage characteristics.
Data Source
AI summary
There is provided a multilayer ceramic electronic component, including: a ceramic body formed by laminating dielectric layers having an average thickness of 0.7 μm or less; external electrodes formed on external surfaces of the ceramic body; and internal electrodes respectively disposed on the dielectric layer so as to have a gap formed therebetween, wherein, when a narrowest gap between the internal electrode edges adjacent to one another is denoted by Gmin, 10 μm≦Gmin≦60 μm is satisfied.