Multilayer Capacitor Electrode Roughness for Moisture Resistance
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving both small size and improved moisture-resistance reliability, as efforts to reduce size and enhance moisture resistance often result in increased component size and lower capacitance.
Innovation Solution
The design incorporates external electrodes with distinct regions of different surface roughness and composition, including agglomerations of flake-shaped and spherical metal particles, and a resin electrode layer to enhance structural stability and moisture resistance, while maintaining capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cover layer or external electrode is made thicker to improve moisture-resistance reliability, then moisture resistance is improved, but the component size increases and capacitance decreases
Solution Approach 1:
The external electrode is divided into two regions with different surface roughness characteristics: a first region with higher surface roughness and a second region with lower surface roughness. This local differentiation allows the first region to provide enhanced moisture resistance while the second region maintains compact dimensions, resolving the contradiction between moisture-resistance reliability and component size.
2Volume of moving object
If the dielectric layer and internal electrodes are made thinner to reduce capacitor size, then component size is reduced, but manufacturing precision and reliability become more difficult to maintain
Solution Approach 1:
The patent changes the surface roughness parameter of the external electrode by creating distinct first and second regions with different roughness characteristics. This parameter modification enhances moisture resistance and structural stability without requiring increases in overall component dimensions, allowing thin-layer designs to maintain adequate manufacturing precision and reliability.
Data Source
AI summary
A multilayer capacitor includes a body including a dielectric layer and a plurality of internal electrodes stacked on each other having the dielectric layer interposed therebetween; and external electrodes including electrode layers positioned externally on the body and connected to the internal electrodes, respectively, wherein the body includes a first surface and a second surface, opposing each other, and to which the plurality of internal electrodes are respectively exposed, and a third surface and a fourth surface which are connected to the first surface and the second surface, and oppose each other in a direction in which the plurality of internal electrodes are stacked on each other, each of the electrode layers including a first region covering the first or second surface and a second region covering the third or fourth surface and having surface roughness lower than that of the first region.