MLCC Rounded Corner Structure for Thin Electrode Plating
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Solution Overview
Problem
Existing methods for producing multilayer ceramic capacitors with thin external electrodes often result in incomplete base electrode formation at corner portions, leading to deteriorated plating properties due to the thickness reduction of external electrodes.
Innovation Solution
A multilayer ceramic capacitor design with a rounded corner portion and specific layer structures, including a central dielectric ceramic layer and internal electrode layers alternately laminated, and a covering portion that ensures the continuity of the base electrode layer and improves plating properties by maintaining a distance of 20 μm or less from the internal electrode to the corner, thereby facilitating effective external electrode formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the external electrode is thinned to achieve small-sized capacitors, then the size is reduced, but the base electrode layer continuity is deteriorated at corner portions
Solution Approach 1:
The patent applies local quality by creating a covering portion with dielectric ceramic layers that specifically covers the corner portions of the laminate. This localized structural modification ensures that the base electrode layer maintains continuity at the corner regions where it would otherwise be discontinuous due to thinning, while allowing the rest of the external electrode to remain thin for miniaturization.
Solution Approach 2:
The patent implements preliminary action by forming the covering portion with dielectric ceramic layers before forming the external electrode. This preliminary structural preparation ensures that when the external electrode is subsequently formed, the base electrode layer can continuously extend to the corner portions, preventing discontinuity issues that would arise from direct thinning of the external electrode.
2Volume of moving object
If the external electrode is thinned to achieve small-sized capacitors, then the size is reduced, but the plating property is deteriorated
Solution Approach 1:
The covering portion is specifically positioned at corner portions where plating properties are most sensitive to external electrode thinning. By providing dielectric ceramic layer coverage at these critical locations, the patent maintains the base electrode layer continuity that is essential for good plating adhesion, while allowing the external electrode to be thin elsewhere.
Solution Approach 2:
The covering portion is formed in advance before external electrode formation, creating a prepared surface structure that ensures proper base electrode layer continuity. This preliminary preparation of the corner regions with dielectric ceramic layers provides a reliable foundation for subsequent plating processes, ensuring excellent plating properties even with thin external electrodes.
3Manufacturing precision
If the corner portion is rounded with small radius, then the base electrode layer continuity is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the laminate structure into a central layer portion and a covering portion. The covering portion is specifically configured to cover the corner regions, creating a modular structure that achieves the rounded corner effect and base electrode layer continuity without requiring complex overall laminate redesign. This segmentation simplifies the manufacturing approach by focusing modifications on specific regions.
Solution Approach 2:
Instead of rounding all corners of the entire laminate with complex tooling, the patent applies the covering portion selectively to the corner regions where base electrode layer continuity is needed. This partial action approach achieves the necessary geometric modification only where required, avoiding unnecessary manufacturing complexity in other regions of the capacitor.
Data Source
AI summary
A multilayer ceramic capacitor includes a laminate and an external electrode connected to the internal electrode layer. The laminate includes a central layer portion in which an internal electrode layer and a dielectric ceramic layer are alternately laminated, and a covering portion covering an outer surface of the central layer portion in the lamination direction and the width direction. A region where the main surface meets the lateral surface in the laminate is defined as a corner portion that is rounded, and a distance from the corner portion to an internal electrode closest to the corner portion is about 20 μm or less.