MLCC Mesh Dummy Layer Mitigates Thermal Stress
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Solution Overview
Problem
Multilayer ceramic capacitors (MLCCs) face reliability issues due to internal stress caused by dissimilar materials with different coefficients of thermal expansion, leading to warpage and potential cracks, which conventional dummy electrode layers with uniform thickness cannot adequately address.
Innovation Solution
Incorporating a dummy layer with a mesh shape made of conductive material in the upper or lower cover layers of the MLCC, alternately stacked with dielectric layers, to enhance strength and stiffness and mitigate stress-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a dummy electrode layer with uniform thickness is disposed on upper and lower cover layers, then strength and stiffness are improved, but the limitation remains in adequately addressing internal stress and warpage issues
Solution Approach 1:
The dummy electrode layer is designed with non-uniform thickness, where the thickness varies in different regions. Specifically, the thickness is greater in regions prone to warpage and internal stress concentration, and thinner in other regions. This local variation in thickness allows the dummy electrode layer to provide enhanced mechanical support precisely where needed, effectively addressing internal stress and warpage issues while maintaining overall strength and stiffness.
2Adaptability or versatility
If dissimilar materials with different coefficients of thermal expansion are used, then functional requirements are met, but internal stress increases causing active cover delamination and cracks
Solution Approach 1:
The thickness parameter of the dummy electrode layer is varied across different regions to compensate for thermal expansion differences. By adjusting the thickness parameter locally, the dummy electrode layer can better accommodate the differential thermal expansion between dissimilar materials, reducing internal stress and preventing delamination and cracks while maintaining the functional requirements of using dissimilar materials.
3Volume of moving object
If the MLCC size is reduced, then miniaturization is achieved, but strength and stiffness become insufficient
Solution Approach 1:
In miniaturized MLCC designs, the dummy electrode layer employs non-uniform thickness distribution to maximize strength and stiffness within the reduced size constraints. By concentrating thicker regions in areas experiencing higher stress and thinner regions elsewhere, the design achieves optimal mechanical performance for the given small size, effectively addressing the strength and stiffness insufficiency problem.
Data Source
AI summary
A multilayer ceramic capacitor includes a ceramic body including a plurality of dielectric layers stacked therein in a stacking direction; first and second external electrodes disposed externally on the ceramic body; first and second internal electrodes alternately stacked with the plurality of dielectric layers, forming an internal active layer of the ceramic body, and respectively connected to the first and second external electrodes; a dummy layer, including a conductive material and having a mesh shape, disposed in at least one of an upper cover layer or a lower cover layer respectively disposed above or below the internal active layer of the ceramic body in the stacking direction.