Multilayer Ceramic Capacitor Electrode Design for Low ESL
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving high Q factor values due to increased equivalent series inductance (ESL), especially in miniaturized forms, leading to performance deterioration and structural defects from internal electrode differences in density and stress.
Innovation Solution
A multilayer ceramic capacitor design with alternately disposed internal electrodes and insulating layers on the ceramic body, increasing the cross-sectional area of internal electrodes to reduce resistance loss and improve Q factor, while maintaining low ESL characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of internal electrodes is increased to increase capacitance, then capacitance is improved, but equivalent series inductance increases and Q factor deteriorates
Solution Approach 1:
The internal electrodes are configured to extend in multiple directions (length direction and width direction) from the ceramic body, transforming a one-dimensional stacking approach into a multi-dimensional current path structure. This increases the effective cross-sectional area for current flow without simply adding more stacked layers, thereby increasing capacitance while maintaining low ESL and high Q factor
Solution Approach 2:
The internal electrodes have different structures in different regions: a body portion spaced apart from the ceramic body edge and lead portions extending to surfaces. This local structural differentiation optimizes current distribution, reducing resistance loss in critical areas while maintaining overall capacitance
2Quantity of substance
If internal electrodes are made thicker or more numerous to increase capacitance, then capacitance is improved, but density difference and internal stress increase causing cracks
Solution Approach 1:
The internal electrodes are divided into distinct functional portions: a body portion and lead portions. This segmentation allows different regions to have optimized thickness and structure, reducing overall density differences during sintering while maintaining sufficient capacitance. The body portion can be thinner than traditional designs, reducing stress concentration
Solution Approach 2:
Different portions of the internal electrodes have different structural characteristics - the body portion is spaced apart from edges while lead portions extend to surfaces. This local structural optimization reduces density differences during sintering and minimizes internal stress, preventing cracks while maintaining capacitance
3Reliability
If internal electrodes are stacked with same polarity to increase Q factor, then Q factor is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The internal electrode structure serves multiple functions simultaneously: it provides capacitance through alternating polarity stacking, reduces ESL through multi-directional current paths, and maintains structural integrity through optimized geometry. The same electrode configuration achieves multiple objectives without requiring separate structures for each function
Solution Approach 2:
Instead of simply stacking electrodes in one direction, the electrodes extend in multiple dimensions (length and width directions) from the ceramic body. This multi-dimensional approach increases effective area and reduces inductance without requiring complex multi-layer stacking arrangements
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 design significantly enhances Q factor values and reduces resistance loss, particularly in high-frequency regions, while minimizing structural defects and improving capacitance, suitable for small-sized capacitors.
Implementation Method 1
first and second insulating layers are formed on the first and second surfaces of the ceramic body in the width direction, respectively, to insulate portions of the first and second lead portions not in contact with the first and second external electrodes
Implementation Method 2
a ceramic body in which a plurality of dielectric layers are stacked and first and second internal electrodes are alternately disposed with respective dielectric layers interposed therebetween
Data Source
AI summary
A multilayer ceramic capacitor includes: a ceramic body in which a plurality of dielectric layers are stacked and first and second internal electrodes are alternately disposed with respective dielectric layers interposed therebetween; and first and second external electrodes formed on first and second surfaces of the ceramic body in a length direction, respectively. The first and second internal electrodes each include a body portion formed to be spaced apart from an edge of the dielectric layer and a lead portion extending from the body portion to be exposed to one surface of the ceramic body in the length direction and portions of the first and second surfaces of the ceramic body in the width direction, and first and second insulating layers are formed on the first and second surfaces of the ceramic body in the width direction, respectively, to insulate portions of the first and second lead portions not in contact with the first and second external electrodes, respectively.