Multilayer Ceramic Capacitor Mg Gradient Margin Design
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Solution Overview
Problem
Multilayer ceramic capacitors face reliability issues due to voids formed at the interface between the ceramic body and side margin portions, leading to decreased breakdown voltage and moisture resistance, especially in miniaturized high-capacitance designs.
Innovation Solution
Adjusting the content of magnesium (Mg) in the side margin and cover portions of the multilayer ceramic capacitor, dividing these regions into distinct compositions to enhance the oxide layer formation and sintering density, thereby improving electrical characteristics and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal electrodes are allowed to be exposed to the body in the width direction to increase the effective area of electrodes, then the capacitance is increased and size is reduced, but voids are formed in the interface between the ceramic body and the side margin portion, deteriorating reliability
Solution Approach 1:
The patent applies local quality by dividing the side margin portion into multiple regions with different magnesium oxide contents. Specifically, the side margin portion is divided into a first region adjacent to the outer surface and a second region adjacent to the internal electrodes, where the second region has a higher magnesium oxide content (0.1-1.0 wt%) than the first region (0.01-0.1 wt%). This localized compositional variation improves the interface quality between the ceramic body and side margin portion, reducing void formation while maintaining the margin-free design for high capacitance density.
2Reliability
If the internal electrodes are allowed to be exposed to the body in the width direction to increase the effective area of electrodes, then the capacitance is increased and size is reduced, but the sintering density of the external portion is deteriorated, decreasing moisture resistance reliability
Solution Approach 1:
The patent applies local quality by creating a gradient in magnesium oxide content within the side margin portion. The first region near the outer surface has lower magnesium oxide content (0.01-0.1 wt%) while the second region near the internal electrodes has higher magnesium oxide content (0.1-1.0 wt%). This localized compositional control improves sintering density in the external portion, enhancing moisture resistance reliability while maintaining the margin-free design for high capacitance density.
3Reliability
If the internal electrodes are allowed to be exposed to the body in the width direction to increase the effective area of electrodes, then the capacitance is increased and size is reduced, but the breakdown voltage decreases due to electric field concentration at the voids
Solution Approach 1:
The patent applies local quality by introducing a magnesium oxide concentration gradient in the side margin portion, with the second region adjacent to internal electrodes containing 0.1-1.0 wt% MgO and the first region adjacent to the outer surface containing 0.01-0.1 wt% MgO. This localized compositional adjustment reduces void formation and electric field concentration at the interface, thereby preventing breakdown voltage decrease while maintaining the margin-free design for high capacitance density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The adjusted magnesium content in the side margin and cover portions increases breakdown voltage and moisture resistance reliability, alleviating electric field concentration and preventing insulation breakdown, while maintaining high capacitance and small size.
Implementation Method 1
Adjusting the content of magnesium (Mg) in the side margin and cover portions of the multilayer ceramic capacitor, dividing these regions into distinct compositions to enhance the oxide layer formation and sintering density
Data Source
AI summary
A multilayer ceramic capacitor includes: a ceramic body including dielectric layers and having first and second surfaces opposing each other; a plurality of internal electrodes disposed in the ceramic body; and first and second side margin portions disposed on end portions of the internal electrodes exposed to the first and second surfaces, wherein the ceramic body includes an active portion, and cover portions disposed on upper and lower surfaces of the active portion, each of the first and second side margin portions is divided into a first region and a second region, each of the cover portions is divided into a first region and a second region, and contents of magnesium (Mg) contained in the second regions of the cover portions and the first and second side margin portions are larger than those of magnesium (Mg) contained in the first regions thereof, respectively.