Multilayer Ceramic Capacitor Electrode Layout for Low ESR
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Solution Overview
Problem
Multilayer ceramic capacitors face an increase in equivalent series resistance (ESR) due to material differences between internal electrode layers and dielectric layers, leading to potential fractures and reduced continuity rates, which affect the direction towards the outer electrode.
Innovation Solution
The design incorporates a multilayer ceramic capacitor structure with alternating internal electrode layers and dielectric layers, where the internal electrode layers have anisotropic current paths and continuity rates optimized by sputtered films, with specific thickness and composition to minimize fractures and enhance continuity, and a manufacturing method involving hydrostatic pressing to achieve these characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked internal electrodes is increased while thinning the internal electrodes to reduce capacitor height and increase capacitance, then the capacitance increases and height reduces, but the internal electrode layers become more prone to breaking due to material differences with dielectric layers
Solution Approach 1:
The patent applies different material compositions to different regions of the internal electrode layer. Specifically, the internal electrode layer contains a base metal (Ni, Cu, or Ti) as the main component, with additional metals (Zn, Al, Mn, Co, or Fe) added in specific amounts (0.1-5 wt% each) to locally enhance strength at critical interfaces with dielectric layers, while maintaining the overall thin profile (1-10 μm) for high capacitance density
Solution Approach 2:
The patent creates a composite internal electrode structure by combining base metal particles with additional metal particles in specific ratios. This composite approach allows the thin internal electrode layer to achieve both high capacitance (through thinness and increased stacking) and improved strength (through the reinforcing effect of the composite metal structure that resists breaking at dielectric interfaces)
2Quantity of substance
If the internal electrode layers are made thinner to increase capacitance density, then the capacitance per unit height increases, but the continuity rate of current paths decreases and ESR increases
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: internal electrode thickness (1-10 μm), base metal particle size (0.1-10 μm), additional metal content (0.1-5 wt%), and organic vehicle composition. These parameter changes ensure that even at thin dimensions, the internal electrode layers maintain sufficient continuity rate by controlling particle distribution and sintering characteristics, thereby keeping ESR low while achieving high capacitance density
3Quantity of substance
If the internal electrode layers are made thinner and more numerous, then the capacitance increases, but the equivalent series resistance increases due to more interfaces with dielectric layers
Solution Approach 1:
The patent applies additional metals (Zn, Al, Mn, Co, or Fe) specifically at interfaces where internal electrode layers contact dielectric layers. This local enhancement reduces contact resistance at each interface, and when combined across multiple layers, significantly reduces the overall ESR even as the number of layers increases for higher capacitance
Solution Approach 2:
The composite metal structure (base metal + additional metals) creates a more conductive path through the multiple internal electrode layers. The specific composition ratios and particle size distributions ensure optimal electrical connectivity across interfaces, reducing the cumulative ESR effect that would normally increase with more stacked layers
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
This configuration effectively suppresses the increase in ESR, maintains high continuity rates, and allows for thinner internal electrode layers, increasing capacitance while reducing the capacitor's height, thereby addressing the challenge of material differences and enhancing performance.
Implementation Method 1
the internal electrode layers have anisotropic current paths and continuity rates optimized by sputtered films
Implementation Method 2
a manufacturing method involving hydrostatic pressing to achieve these characteristics
Implementation Method 3
sintering the element body that has the conductive paste applied thereon, such that the electrode pattern is integrated with the dielectric slurry film
Data Source
AI summary
A multilayer ceramic capacitor includes an element body. The element body includes a stack of first internal electrode layers, dielectric layers and second internal electrode layers. The element body has a first surface and a second surface opposite the first surface. The multilayer ceramic capacitor also includes a first external electrode formed on the first surface of the element body and a second external electrode formed on the second surface of the element body. The first internal electrode layer has a first current path extending in a first plane perpendicular to the first surface such that the first current path has a shorter component on the first plane in a first direction toward the first surface than in a second direction perpendicular to the first direction. The second internal electrode layer has a second current path that possesses a similar anisotropy to the first internal electrode layer.