Multilayer Ceramic Capacitor Cover Portions Density Gradient
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving high reliability due to humidity penetration, which affects their reliability and performance, especially with the miniaturization and multifunctionalization of electronic products, where thin dielectric layers and high capacitance are required.
Innovation Solution
The design includes a ceramic body with internal and external electrodes, where the cover portions have a higher dielectric material density than the active portions, reducing sintering mismatch and enhancing humidity resistance by adjusting the density and thickness ratios of the dielectric material in specific regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric layer thickness is reduced to achieve miniaturization and high capacitance, then the capacitance density increases, but the reliability deteriorates due to humidity penetration and sintering mismatch
Solution Approach 1:
The patent applies local quality by creating a cover portion with different dielectric material density characteristics than the active portion. Specifically, the cover portion has a first region with lower dielectric material density adjacent to external side surfaces, which prevents harmful effects like humidity penetration and sintering mismatch, while the inner regions maintain high capacitance density through proper dielectric layer configuration.
2Volume of moving object
If the dielectric layer thickness is reduced to achieve miniaturization, then the component size decreases, but the humidity resistance characteristics deteriorate
Solution Approach 1:
The patent creates a protective structure by forming a cover portion with reduced dielectric material density in the first region adjacent to external side surfaces. This local modification provides humidity resistance characteristics without increasing overall component size, as the low-density region acts as a barrier against humidity penetration while maintaining the miniaturized form factor.
3Quantity of substance
If the dielectric layer thickness is reduced to achieve high capacitance, then the capacitance increases, but the sintering mismatch increases causing defects
Solution Approach 1:
The patent resolves sintering mismatch by creating a cover portion with differentiated density characteristics. The first region adjacent to external side surfaces has lower dielectric material density, which compensates for the high capacitance density in the active portion and prevents excessive sintering mismatch that would cause defects during the sintering process.
4Volume of moving object
If the internal electrode thickness is reduced to achieve miniaturization, then the component size decreases, but the adhesion to external electrodes deteriorates
Solution Approach 1:
The patent maintains adhesion strength in miniaturized components by creating a cover portion with reduced dielectric material density in the first region adjacent to external side surfaces. This low-density region provides adequate adhesion between internal and external electrodes, ensuring mechanical strength is maintained even when internal electrode dimensions are reduced for miniaturization.
Data Source
AI summary
A multilayer ceramic capacitor includes a ceramic body including dielectric layers and first and second internal electrodes disposed to face each other with each of the dielectric layers interposed therebetween, and first and second external electrodes disposed on external surfaces of the ceramic body and electrically connected to the first and second internal electrodes, respectively. The ceramic body includes an active portion in which capacitance is formed and cover portions disposed above and below the active portion. Each of the cover portions includes a first region adjacent to an external side surface of the ceramic body and a second region adjacent to an outermost internal electrode and disposed between the first region and the active region. A density of a dielectric material included in the second region is higher than a density of a dielectric material included in the first region.