Multilayer Capacitor Curved Cover Edges Warpage
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in miniaturization and increased capacitance due to warpage phenomena caused by thickness differences between internal electrodes and dielectric layers, leading to reduced reliability and moisture resistance issues.
Innovation Solution
A multilayer capacitor design with a stacked structure of dielectric layers and internal electrodes, where the body is divided into central and cover portions with curved corner edges, and internal electrodes are narrower in the cover portions, optimizing radii of curvature and margin ratios to enhance reliability and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked dielectric layers and internal electrodes is increased to increase capacitance and miniaturize the capacitor, then capacitance and integration density are improved, but warpage phenomenon and reliability are deteriorated
Solution Approach 1:
The patent segments the body into a central portion and cover portions, with internal electrodes having different widths in different regions. This segmentation allows the capacitor to accommodate warpage effects in the cover portions while maintaining high capacitance through increased layer stacking in the central portion, thus resolving the contradiction between increased capacitance and maintained reliability.
Solution Approach 2:
The patent applies local quality by making internal electrodes narrower in the cover portions compared to the central portion. This local variation in electrode geometry allows the capacitor to handle thickness differences and warpage locally in the cover portions while maintaining high capacitance density in the central portion, thereby improving reliability without sacrificing capacitance.
2Productivity
If end surface margin portions are formed to have small thickness to improve productivity, then manufacturing efficiency is improved, but moisture resistance reliability is deteriorated
Solution Approach 1:
The patent applies curvature by forming corner edges with curved surfaces having different radii of curvature (R1 > R2). This curved geometry naturally provides larger margin portions at the corners without requiring additional processing steps, thereby maintaining moisture resistance reliability while improving manufacturing efficiency through a single-forming process.
Data Source
AI summary
A multilayer capacitor includes a body including a stacked structure formed of a plurality of dielectric layers, and a plurality of internal electrodes, and external electrodes, wherein the body is divided into a central portion, and cover portions, the body has first to sixth surfaces, in the body, the cover portion forms corner edges having a curved surface, and if a radius of curvature of each of the corner edges at which the third and fourth surfaces meet the fifth and sixth surfaces refers to R1, and a radius of curvature of each of the corner edges at which the third and fourth surfaces meet the first and second surfaces refers to R2, a relationship of R1>R2 is satisfied, and a width of an internal electrode disposed in the cover portion is narrower than a width of an internal electrode disposed in the central portion.