Multi-layer Ceramic Capacitor Ridge Protrusion for Moisture Protection
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Solution Overview
Problem
Multi-layer ceramic capacitors face a higher risk of short circuits due to moisture ingress, particularly when their thin external electrodes overlap with cracked ceramic bodies, leading to reliability issues.
Innovation Solution
The design incorporates a protrusion on the external electrode along the ridge of the ceramic body, which thickens the electrode in critical areas to prevent moisture entry and reduce equivalent series resistance (ESR) and equivalent series inductance (ESL), while maintaining thin base portions for reduced peeling risks, and includes a plating layer and underlayer formed by vacuum film deposition for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the external electrode is made thinner to reduce height, ESR, and ESL, then the height and electrical performance are improved, but the reliability deteriorates due to increased susceptibility to short circuits from moisture ingress through cracks
Solution Approach 1:
The external electrode is designed with non-uniform thickness, featuring a thicker portion at the ridge and thinner portions at the side surfaces. This local quality variation allows the electrode to provide enhanced moisture protection at the crack-prone ridge area while maintaining thin thickness at other areas to reduce overall height, ESR, and ESL.
Solution Approach 2:
The thicker portion of the external electrode is positioned in advance at the ridge location where cracks are most likely to form and where moisture ingress would cause short circuits. This preliminary protective structure prevents moisture from reaching the internal electrodes through cracks before the short circuit can occur.
2Length of moving object
If the external electrode is made thinner to reduce height, then the height is improved, but the protection against moisture entry through cracks deteriorates
Solution Approach 1:
The external electrode is designed with non-uniform thickness, featuring a thicker portion at the ridge and thinner portions at the side surfaces. This local quality variation allows the electrode to provide enhanced moisture protection at the crack-prone ridge area while maintaining thin thickness at other areas to reduce overall height, ESR, and ESL.
Solution Approach 2:
The ridge structure, which is naturally more susceptible to cracking due to stress concentration, is converted into a beneficial feature by placing the thicker protective portion of the external electrode exactly at this location. The potential harm from cracks at the ridge is transformed into a strategically positioned moisture barrier where it is most needed.
3Reliability
If the external electrode thickness is increased to prevent short circuits, then the reliability is improved, but the height and ESR increase
Solution Approach 1:
The external electrode is designed with non-uniform thickness, featuring a thicker portion at the ridge and thinner portions at the side surfaces. This local quality variation allows the electrode to provide enhanced moisture protection at the crack-prone ridge area while maintaining thin thickness at other areas to reduce overall height, ESR, and ESL.
Solution Approach 2:
Instead of uniformly increasing the external electrode thickness throughout, the invention applies excessive thickness only partially at the critical ridge location where moisture protection is most needed, while maintaining appropriate or reduced thickness at other areas. This partial application of the protective measure achieves the necessary reliability without the full penalty of increased height and ESR.
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 prevents short circuits, enhances the reliability of multi-layer ceramic capacitors by shielding the ceramic body from moisture, and minimizes ESR and ESL, ensuring high performance and durability.
Implementation Method 1
forming an underlayer in the lead-out region by a vacuum film deposition method
Implementation Method 2
forming a plating layer including a protrusion extending along the ridge and protruding in the directions of the first axis and the second axis, and a first base portion and a second base portion extending from the protrusion along the first side surface and the second side surface, respectively, the plating layer covering the lead-out region via the underlayer
Data Source
AI summary
A multi-layer ceramic electronic component includes a ceramic body and an external electrode. The ceramic body includes a first side surface facing in a direction of a first axis, a second side surface facing in a direction of a second axis orthogonal to the first axis, a ridge that connects the first side surface and the second side surface to each other, and internal electrodes laminated along a third axis orthogonal to the first axis and the second axis and led out in a lead-out region. The external electrode includes a protrusion provided at a position along the ridge and protruding in the directions of the first axis and the second axis, and a first base portion and a second base portion extending from the protrusion along the first side surface and the second side surface, respectively, the external electrode covering the lead-out region.