Multilayer Ceramic Capacitor Side Margins for Insulation Breakdown
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Solution Overview
Problem
Multilayer ceramic capacitors face insulation breakdown due to concentrated electric fields at the ends of internal electrodes, which is a major defect that existing manufacturing methods fail to adequately address, especially in miniaturized and high-capacitance designs.
Innovation Solution
The solution involves creating a multilayer ceramic capacitor with side margin portions made of a dielectric composition that has a lower dielectric constant than the ceramic body, specifically by adjusting the content of subcomponents like manganese, silicon, sodium, and lithium, to disperse and reduce the electric field at the ends of internal electrodes, thereby preventing insulation breakdown and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the internal electrode is exposed in the width direction to increase effective electrode area, then miniaturization and high-capacitance are achieved, but electric field concentration at the electrode end causes insulation breakdown
Solution Approach 1:
The patent applies local quality by differentiating the dielectric composition between the ceramic body and the side margin portions. The side margin portions have a different dielectric constant than the ceramic body, creating localized property variation. This allows the electrode ends to be exposed for high capacitance while the distinct dielectric material in margin portions mitigates electric field concentration, preventing insulation breakdown.
2Reliability
If a margin portion is separately attached to the exposed surface of the electrode, then insulation breakdown is prevented, but device complexity and manufacturing complexity increase
Solution Approach 1:
The patent merges the margin portion formation into the sintering process itself. The side margin portions are formed simultaneously with the ceramic body through co-sintering of green sheets with different dielectric compositions. This integration eliminates separate attachment steps, reducing manufacturing complexity while maintaining the reliability benefit of differentiated dielectric materials at the electrode margins.
3Reliability
If a margin portion is separately attached to the exposed surface of the electrode, then insulation breakdown is prevented, but manufacturing precision and process difficulty increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring the green sheets with different dielectric compositions in specific patterns before sintering. The side margin portions are formed as integral parts of the green sheet stack, with their positions and dimensions predetermined during green sheet preparation. This eliminates the need for post-sintering alignment and attachment operations, significantly reducing manufacturing precision requirements and process difficulty.
Data Source
AI summary
A multilayer ceramic capacitor include: a ceramic body including first and second surfaces opposing each other and third and fourth surfaces connecting the first and second surfaces; a plurality of internal electrodes disposed inside the ceramic body and exposed to the first and second surfaces, the plurality internal electrodes each having one end exposed to the third or fourth surface; and first and second side margin portions disposed on sides of the internal electrodes exposed to the first and second surfaces. A dielectric composition of the first and second side margin portions is different from a dielectric composition of the ceramic body, and a dielectric constant of the first and second side margin portions is lower than a dielectric constant of the ceramic body.