Multilayer Ceramic Capacitor Electrode Holes for Breakdown Control
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Solution Overview
Problem
Conventional multilayer ceramic capacitors face challenges in reducing dielectric layer thickness while maintaining capacitance and preventing electric field concentration, which can lead to dielectric breakdown during voltage application.
Innovation Solution
The design incorporates thin dielectric layers sandwiched between internal electrode layers with specific hole configurations, where the area equivalent diameter of holes follows a cumulative distribution, ensuring that the thickness of dielectric layers is 0.6 μm or less and the area equivalent diameter D99 is less than 0.1468×exp(6.7622×t, to reduce electric field concentration without compromising capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of dielectric layers is reduced to increase capacitance and reduce size, then the capacitance increases and the capacitor size decreases, but the electric field strength increases and dielectric breakdown occurs more easily
Solution Approach 1:
The internal electrode layers are designed with non-uniform hole distributions, where the density and size of holes vary in different regions. Specifically, the first internal electrode layer has a different hole distribution compared to the second internal electrode layer, creating localized variations in electric field strength that prevent concentration at any single point while maintaining overall high capacitance through the thin dielectric structure.
2Volume of moving object
If the thickness of dielectric layers is reduced to decrease capacitor size, then the capacitor dimensions decrease, but the electric field concentration increases and reliability decreases
Solution Approach 1:
The invention changes the parameters of the internal electrode layers by controlling the hole characteristics (size, density, and distribution) in different layers. By adjusting these parameters, the electric field distribution is optimized to prevent concentration effects even when the dielectric layer thickness is reduced to minimize capacitor size. The specific parameter control ensures that the product of dielectric thickness and hole area equivalent diameter remains within safe limits.
3Reliability
If auxiliary electrodes are added to increase breakdown voltage, then the dielectric breakdown resistance improves, but the capacitor active portion area decreases and capacitance is compromised
Solution Approach 1:
Instead of using traditional auxiliary electrodes that occupy space and reduce active area, the invention segments the internal electrode layers themselves by creating controlled holes within them. This segmentation approach distributes the electric field management function across multiple layers rather than relying on separate auxiliary electrodes, thereby maintaining maximum active portion area while achieving enhanced breakdown voltage resistance through the segmented hole structures.
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including a dielectric layers and internal electrode layers laminated on each other, and first and second external electrodes. The internal electrode layers include first and second internal electrode layers each respectively electrically connected to the first and second external electrodes. The first and second internal electrode layers include holes with different area equivalent diameters. A thickness of each of the dielectric layers is about 0.6 μm or less and (area equivalent diameter D99)<about 0.1468×exp(6.7622×t) is satisfied.