Multilayer Ceramic Electrode Recess Structure for Flex Crack Resistance
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Solution Overview
Problem
Multilayer ceramic capacitors face issues with flexural resistance, leading to potential cracks when mounted on a board due to bending stress in the external electrodes.
Innovation Solution
The design includes a multilayer ceramic component with external electrodes featuring a recessed structure on the main surfaces, where the surface roughness of the recess is rougher than the peripheral region, and a flexible electrically conductive resin layer to act as a buffer, reducing stress transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external electrodes are made rigid to ensure structural stability, then electrical connection is improved, but bending stress increases and causes cracks in the multilayer body
Solution Approach 1:
The patent applies a flexible resin layer between the external electrode and the multilayer body. This resin layer acts as a buffer that absorbs bending stress during mounting, preventing stress transmission to the multilayer body while maintaining electrical connection. The flexible film allows the external electrode to deform without transferring harmful stresses to the ceramic structure.
Solution Approach 2:
The resin layer serves as an intermediary element between the external electrode and the multilayer body. It mediates the mechanical stress by absorbing and dissipating bending forces, preventing direct stress transmission that would cause cracks. This intermediary layer decouples the rigid external electrode from the fragile multilayer structure.
2Ease of manufacture
If the external electrode structure is simplified for ease of manufacture, then production cost decreases, but stress distribution becomes uneven causing cracks
Solution Approach 1:
The patent introduces a recess portion in the external electrode with different surface roughness characteristics. The recess portion has a specific surface roughness that differs from other regions, creating local quality variations that improve stress distribution. This local modification is achieved through simple processes like sandblasting or chemical treatment, maintaining ease of manufacture while improving reliability.
3Ease of operation
If the surface of the external electrode is made smooth for better soldering, then mounting process is improved, but stress concentration increases leading to cracks
Solution Approach 1:
The patent creates different surface roughness zones on the external electrode: a smooth peripheral region for good soldering and a recess portion with controlled roughness for stress distribution. This local quality differentiation allows the electrode to simultaneously achieve good soldering properties and stress resistance. The rough recess portion can be created by sandblasting, while the peripheral region remains smooth.
Data Source
AI summary
A multilayer ceramic electronic component includes a multilayer body and a pair of external electrodes at both ends of the multilayer body. The external electrodes include a main surface-side external electrode including a recess recessed towards a multilayer body side in a cross-sectional view along a lamination direction and a length direction of the multilayer body, and peripheral regions adjacent to the recess in the length direction. A surface roughness of the recess is rougher than a surface roughness of the peripheral regions.