Multilayer Ceramic Capacitor Grain Structure for Capacitance and Reliability
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in maintaining effective capacitance and reliability due to suppressed grain growth of dielectric particles, which affects the progress of sintering and solid solution of rare earth elements, leading to decreased reliability.
Innovation Solution
The multilayer ceramic capacitor is sectioned into specific regions with varying dielectric particle sizes and compositions, including core-shell and homogeneous solid solution particles, to enhance capacitance and reliability by controlling grain growth and oxygen vacancy migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grain growth of dielectric particles is suppressed to low level to reduce capacitance change and increase effective capacitance, then effective capacitance is improved, but reliability decreases due to impeded solid solution of rare earth element
Solution Approach 1:
The patent applies local quality by creating distinct regions with different dielectric particle size characteristics. The central region has dielectric particles with smaller area equivalent diameter (suppressing grain growth) to reduce capacitance change, while the side margin adjacent regions have dielectric particles with larger area equivalent diameter (promoting grain growth) to ensure adequate solid solution of rare earth elements. This spatial differentiation resolves the contradiction by allowing each region to optimize for its specific functional requirement.
2Reliability
If sintering progress is retarded to suppress grain growth, then capacitance change is reduced, but solid solution of rare earth element is impeded
Solution Approach 1:
The patent segments the dielectric layer into functionally distinct regions: a central region where sintering is retarded to suppress grain growth and reduce capacitance change, and side margin adjacent regions where sintering progresses adequately to enable solid solution of rare earth elements. This segmentation allows the system to simultaneously achieve capacitance stability and proper rare earth element incorporation by distributing different sintering characteristics across different spatial zones.
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 design improves effective capacitance and reliability by promoting grain growth in critical regions while suppressing it where necessary, thereby enhancing insulation resistance and moisture resistance.
Implementation Method 1
Dielectric particles in the dielectric layer in the first side margin adjacent region and the second side margin adjacent region have a larger area equivalent diameter than dielectric particles in the dielectric layer in the central region
Implementation Method 2
retarding the progress of sintering of the dielectric particles to suppress the grain growth of the dielectric particles
Implementation Method 3
the progress of the solid solution of a rare earth element is also impeded or restricted
Data Source
AI summary
A multilayer ceramic capacitor includes a laminate including dielectric layers and internal electrode layers laminated in a thickness direction, and a pair of external electrodes. An inner layer portion of the laminate includes a central region in a widthwise center, a first side margin adjacent region adjacent to a first side margin, and a second side margin adjacent region adjacent to a second side margin. An area equivalent diameter of dielectric particles in dielectric layers of the first side margin adjacent region and the second side margin adjacent region is larger than an area equivalent diameter of dielectric particles in the dielectric layer of the central region.