Multi-Layer Ceramic Capacitor Stepped External Electrode
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Solution Overview
Problem
Substrates with built-in multi-layer ceramic capacitors face connection reliability issues due to differing thermal expansion coefficients between the ceramic capacitors and the insulating substrate, leading to stress on electrode connections during heating and cooling.
Innovation Solution
A multi-layer ceramic electronic component design featuring a ceramic body with internal electrodes and an external electrode configuration that includes a base layer with a step portion and a plated layer, enhancing connection reliability by increasing the connection area and requiring force application in multiple directions for joint release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-layer ceramic electronic component is incorporated in or mounted to a wiring substrate, then the component achieves functional integration, but stress is applied to the connection boundary between the external electrode and the via hole due to thermal expansion differences, reducing connection reliability
Solution Approach 1:
The patent introduces a step portion that creates a height difference in the external electrode structure, transforming a two-dimensional connection interface into a three-dimensional stepped structure. This dimensional change increases the connection area and distributes thermal stress across multiple surfaces, reducing the stress concentration at the connection boundary between the external electrode and the via hole.
Solution Approach 2:
The external electrode is segmented into multiple levels by the step portion, creating distinct connection surfaces at different heights. This segmentation allows the connection to be distributed across multiple interfaces rather than concentrated at a single boundary, thereby reducing the stress applied to any single connection point during thermal cycling.
2Strength
If the connection area between the external electrode and via hole is increased, then connection strength is improved, but the device size increases, hindering miniaturization
Solution Approach 1:
Instead of increasing the connection area in the planar direction (which would increase device footprint), the patent utilizes the vertical dimension by creating a step portion. This allows the connection area to be expanded upward, increasing connection strength without increasing the lateral dimensions of the component, thus enabling miniaturization while maintaining strong connections.
Solution Approach 2:
The step portion is strategically positioned at the connection boundary between the external electrode and the via hole, concentrating the area increase locally at the critical connection point rather than uniformly across the entire component. This localized quality change enhances connection strength where needed without increasing the overall device size.
Data Source
AI summary
A multi-layer ceramic electronic component includes: a ceramic body including internal electrodes laminated in one axial direction and having a main surface facing in the one axial direction; and an external electrode including a base layer including a step portion formed on the main surface, and a plated layer formed on the base layer, the external electrode being connected to the internal electrodes.