Multilayer Ceramic Capacitor Corners for Moisture-Resistant Adhesion
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Solution Overview
Problem
Miniaturization of electronic components leads to reduced moisture resistance due to insufficient adhesion between insulating layers and capacitor main portions, allowing moisture infiltration.
Innovation Solution
A multilayer ceramic capacitor design with exposed internal electrode layers at lateral surfaces and corner portions with increased roughness, covered by insulating portions to enhance adhesion and prevent moisture infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the dimensions of electronic components are decreased to achieve miniaturization, then the size of the capacitor is reduced, but the overlapping area between internal electrodes becomes smaller, making it difficult to increase capacitance
Solution Approach 1:
The patent extends internal electrodes not only in the stacking direction but also laterally beyond the boundaries of dielectric layers, creating a three-dimensional electrode configuration. This dimensional extension increases the effective overlapping area for capacitance generation without increasing the overall footprint area of the capacitor, thus resolving the contradiction between miniaturization and capacitance enhancement.
Solution Approach 2:
The patent employs a multi-layer structure where internal electrodes are nested between dielectric layers in a stacked configuration, with additional lateral extension. This nesting approach allows maximum utilization of the available volume space, enabling higher capacitance within a compact form factor by efficiently packing electrode-dielectric-electrode units in both vertical and lateral dimensions.
2Quantity of substance
If internal electrode layers are exposed at lateral surfaces to maximize electrode area, then capacitance is increased, but adhesion between insulating layers and capacitor main portion becomes insufficient, allowing moisture infiltration
Solution Approach 1:
The patent applies different surface treatments to different regions of the capacitor. Specifically, corner portions of the capacitor body receive a roughness treatment with Ra value of 0.3 μm or more, while other regions maintain their original surface characteristics. This localized roughness enhancement at corners specifically addresses adhesion and moisture resistance at these critical locations without affecting the overall electrode area or capacitance.
Solution Approach 2:
The roughness treatment is applied in advance to corner portions before final assembly and sealing operations. This preliminary surface preparation creates optimal conditions for subsequent insulating material bonding and moisture barrier formation, preventing moisture infiltration pathways before they can develop into reliability issues.
3Reliability
If corner portions are treated with increased roughness to improve adhesion, then moisture resistance is enhanced, but the surface finish of the capacitor is altered
Solution Approach 1:
The roughness treatment is selectively applied only to corner portions of the capacitor body, leaving the main surfaces and other regions unchanged. This localized approach enhances moisture resistance at critical corner locations where moisture infiltration is most likely to occur, while maintaining the original aesthetic and functional surface finish of the bulk capacitor structure.
Data Source
AI summary
A multilayer ceramic capacitor includes a capacitor main portion including first, second, third, and fourth corner portions. The first insulating portion covers the first and second corner portions, and the second insulating portion covers the third and fourth corner portions. A roughness of the first corner portion is greater than a roughness of the first outer corner portion, a roughness of the second corner portion is greater than a roughness of the second outer corner portion, a roughness of the third corner portion is greater than a roughness of the third outer corner portion, and a roughness of the fourth corner portion is greater than a roughness of the fourth outer corner portion.