MLCC Electrode and Dielectric Layout for Void-Resistant Capacitance
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in maintaining high capacitance and reliability due to voids generated in internal electrodes during firing, leading to decreased active area and capacitance, and increasing the relative dielectric constant to address this issue compromises reliability.
Innovation Solution
The design incorporates a multilayer body with specific configurations of dielectric layers and internal electrodes, including high and low coverage portions, and high and low dielectric constant portions, where the high dielectric constant portions are strategically placed to maintain capacitance while reducing the need for increased relative dielectric constants across all layers, thereby minimizing reliability degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the internal electrodes are thinned to enable miniaturization and increased capacitance, then the number of laminated layers can be increased and device size reduced, but voids are generated in the internal electrodes after firing leading to decreased active area and capacitance
Solution Approach 1:
The patent applies local quality by differentiating the coverage ratio of internal electrodes in different regions. The first internal electrode has a first coverage ratio in a first region and a second coverage ratio in a second region, with the first coverage ratio being greater than the second. This non-uniform coverage distribution optimizes the balance between capacitance (requiring higher coverage) and void prevention (requiring lower coverage in certain areas), thereby maintaining internal electrode integrity while achieving high capacitance density.
2Reliability
If the relative dielectric constant is increased in all dielectric layers to compensate for capacitance loss, then capacitance can be maintained, but reliability of the multilayer ceramic capacitor is lowered
Solution Approach 1:
The patent applies local quality by creating distinct dielectric layers with different relative dielectric constants in specific regions. The first dielectric layer has a first relative dielectric constant in a first region and a second relative dielectric constant in a second region, with the first being greater than the second. This localized high dielectric constant region compensates for capacitance loss without requiring all layers to have high dielectric constants, thereby maintaining overall reliability while achieving high capacitance.
3Productivity
If the dielectric layers are made thinner and the number of laminated layers is increased to achieve miniaturization, then capacitance density improves, but the complexity of manufacturing and maintaining uniformity increases
Solution Approach 1:
The patent applies segmentation by dividing the dielectric structure into multiple distinct layers (first dielectric layer, second dielectric layer, third dielectric layer) with different properties in different regions. This segmentation allows each layer to be optimized for specific functions (capacitance generation, void prevention, structural integrity) while maintaining manufacturability through standardized lamination processes.
Solution Approach 2:
The patent applies local quality by creating region-specific properties within dielectric layers. The first dielectric layer has different relative dielectric constants in different regions, and internal electrodes have different coverage ratios in different regions. This localized optimization enables thin-layer construction with high capacitance density while managing manufacturing complexity through controlled regional variations rather than uniform changes throughout the entire structure.
Data Source
AI summary
A multilayer ceramic capacitor includes a first internal electrode, a second internal electrode, a first dielectric layer, and a second dielectric layer. The first internal electrode includes a first outer peripheral portion and a first inner electrode portion inside the first outer peripheral portion. The second internal electrode includes a second outer peripheral portion and a second inner electrode portion inside the second outer peripheral portion. The first dielectric layer includes a first high dielectric constant portion, and a first inner dielectric layer portion inside the first high dielectric constant portion. The second dielectric layer include a second high dielectric constant portion and a second inner dielectric layer portion inside the second high dielectric constant portion.