Multilayer Ceramic Capacitor Electrode Layout to Prevent Layer Peeling
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Solution Overview
Problem
In multilayer ceramic capacitors, the difference in internal stress between layers, particularly in lead-out regions, can lead to peeling-off of one layer from another due to varying shrinkage directions during sintering.
Innovation Solution
The introduction of auxiliary internal electrodes on adjacent layers in lead-out regions, which are spaced apart from the main internal electrodes and exposed at the lateral or end surfaces, helps to reduce the difference in internal stress by ensuring that both layers have internal electrodes in these regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If internal electrodes are arranged with different extension directions in alternating layers, then multi-terminal functionality is achieved, but difference in internal stress between layers increases causing peeling-off
Solution Approach 1:
The internal electrode in each dielectric layer is segmented into two distinct portions: a counter portion that faces the opposing electrode, and a lead-out portion that extends toward the surface for external connection. This segmentation allows the electrode to fulfill multiple functions while managing stress distribution differently in each portion, reducing peeling-off at layer interfaces.
Solution Approach 2:
Different portions of the internal electrode are designed with different local qualities and configurations. The counter portion is optimized for electrical opposition and capacitance formation, while the lead-out portion is extended and positioned to manage mechanical stress during sintering. This local differentiation resolves the contradiction by allowing each region to optimize for its specific function.
2Ease of operation
If lead-out portions of internal electrodes are disposed in specific regions, then external connectivity is enabled, but internal stress concentration occurs in lead-out regions causing peeling-off
Solution Approach 1:
The lead-out portion of the internal electrode extends not only in the plane of the dielectric layer but also in the thickness direction toward the surface. This three-dimensional configuration allows the electrode to reach external connection points while distributing mechanical stress more effectively during sintering, reducing concentration at the layer interface.
Solution Approach 2:
The lead-out portion is pre-configured during the green sheet lamination stage to extend toward the surface before sintering. This preliminary positioning ensures that during the subsequent sintering process, the electrode already has a stress-distributing configuration in place, preventing stress concentration and peeling-off that would occur if the electrode were forced into position after sintering.
Data Source
AI summary
A multilayer ceramic capacitor includes end-surface-exposure internal electrodes, lateral-surfaces-exposure internal electrodes, first dielectric layers each having the end-surface-exposure internal electrode thereon, and second dielectric layers each having the lateral-surface-exposure internal electrode thereon. At least one of each first and second dielectric layer includes an auxiliary internal electrode on a portion adjacent to one surface at which the internal electrode is not exposed. The auxiliary internal electrode is spaced apart from the internal electrode, is exposed at the one surface, and is opposed to a lead-out portion of the internal electrode different from and adjacent to the internal electrode. A through hole penetrates through the auxiliary internal electrode and includes a same dielectric as that of the dielectric layers to connect the dielectric layers in contact with the auxiliary internal electrode.