Multilayer Ceramic Capacitor Electrode Structure for Crack Resistance
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Solution Overview
Problem
Multilayer ceramic capacitors are prone to cracking when subjected to stress from substrate bending due to the transmission of stress through solder and external electrodes, particularly at the junctions of opposing end portions, which can lead to short circuits.
Innovation Solution
The multilayer ceramic capacitor design includes a multilayer body with internal electrodes exposed on multiple surfaces and external electrodes connected to these internal electrodes, featuring a flexible resin electrode layer that acts as a buffer, reducing stress concentration and preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external electrodes are provided on lateral surfaces to enable three-terminal configuration, then electrical connectivity is improved, but stress concentration and crack occurrence increase at electrode-multilayer body junctions
Solution Approach 1:
A resin layer is introduced between the external electrode and the multilayer body to act as a flexible buffer that absorbs stress. This resin layer has different mechanical properties compared to the rigid ceramic multilayer body, allowing it to deform and reduce stress concentration at the electrode junctions, thereby preventing cracks while maintaining the three-terminal electrical connectivity configuration
2Ease of operation
If the multilayer body is mounted on substrate by soldering, then electrical connection is established, but stress from substrate bending is transmitted to the multilayer body causing cracks
Solution Approach 1:
The resin layer serves as an intermediary element between the soldered external electrode and the multilayer body. When the substrate bends and stress is transmitted through the solder and electrode, the resin layer absorbs and dissipates this stress before it reaches the multilayer body, preventing crack formation while maintaining the mounting capability
3Adaptability or versatility
If base electrode layers are extended to multiple surfaces for internal electrode connection, then electrical pathways are improved, but stress distribution and crack risk are worsened
Solution Approach 1:
The resin layer is positioned to cover regions where base electrode layers extend across multiple surfaces, particularly at the intersections and edges where stress concentration occurs. This flexible film absorbs the mechanical stress that would otherwise concentrate at these electrode extension points, preventing cracks while allowing the electrical pathways to function
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 effectively reduces or prevents cracking and enhances moisture resistance by distributing stress and providing a flexible buffer layer, improving the reliability of the capacitor under mechanical and thermal cycling.
Implementation Method 1
reducing stress concentration and preventing cracks
Implementation Method 2
flexible resin electrode layer that acts as a buffer
Data Source
Figure 1
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AI summary
Provided are multilayer ceramic capacitors that are each able to reduce or prevent the occurrence of cracks. A first external electrode 3A includes a first base electrode layer 31A of the first external electrode connected to first internal electrodes 15A and provided from a fifth surface F5 to a first surface F1, a second base electrode layer 32A of the first external electrode connected to the first internal electrode 15A and provided from a sixth surface F6 to the first surface F1, a first resin electrode layer 34A provided over the first base electrode layer 31A of the first external electrode, the first surface F1, and the second base electrode layer 32A of the first external electrode, and a first plated layer 36A provided on the first resin electrode layer 34A. The first surface F1 includes a first region 21 which is a region between a region where the first base electrode layer 31A of the first external electrode is provided and a region where the second base electrode layer 32A of the first external electrode is provided, and which is a region where the first resin electrode layer 34A is provided. The first region 21 overlaps, in the lamination direction T, with a middle portion of a multilayer body 2 in a second direction W.