Multilayer Ceramic Capacitor Electrodes With Thicker Edge Coverage
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Solution Overview
Problem
During barrel processing of multilayer ceramic capacitors, the outer peripheral portion of the base electrode layer is cut, exposing the end surface and allowing plating solution to penetrate, leading to insufficient performance.
Innovation Solution
The external electrodes of the multilayer ceramic capacitor are designed with a central portion and an outer peripheral portion, where the thickness relationship is L1<L2, to prevent penetration and ensure adequate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If barrel processing is performed on the multilayer body with base electrode layer, then the external electrodes can be formed, but the outer peripheral portion of the base electrode layer is cut and the end surface is exposed
Solution Approach 1:
The base electrode layer is designed with non-uniform thickness: a thicker outer peripheral portion (thickness L2) and a thinner central portion (thickness L1), where L1 < L2. This local quality variation ensures that the thicker outer peripheral portion remains after barrel processing, preventing end surface exposure while still allowing external electrode formation.
2Device complexity
If the base electrode layer is made uniformly thick, then manufacturing is simpler, but plating solution penetrates into the multilayer body when the outer peripheral portion is cut
Solution Approach 1:
The base electrode layer employs local quality variation with different thicknesses: the outer peripheral portion has thickness L2 and the central portion has thickness L1, where L1 < L2. This design concentrates the protective function at the outer peripheral portion, preventing plating solution penetration while keeping the overall structure relatively simple.
3Reliability
If the outer peripheral portion thickness L2 is increased to prevent end surface exposure, then reliability improves, but the central portion thickness L1 must be reduced
Solution Approach 1:
The base electrode layer is designed with localized thickness variation where the outer peripheral portion (thickness L2) is thicker than the central portion (thickness L1). This allows the thicker outer peripheral portion to provide sufficient coverage and protection after barrel processing, while the central portion can be thinner since it does not require the same level of protection against end surface exposure.
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including internal electrode layers and internal dielectric layers alternately laminated therein, main surfaces on both sides in a lamination direction, end surfaces on both sides in a length direction intersecting the lamination direction, and lateral surfaces on both sides in a width direction intersecting the lamination direction and the length direction, and two external electrodes on the end surfaces of the multilayer body. The two external electrodes each include a central portion having a thickness L1, and located at a center or approximate center in the lamination direction and at a center or approximate center in the width direction, and an outer peripheral portion surrounding the central portion and having a thickness L2, where a relationship therebetween is L1<L2.