Multilayer Ceramic Capacitor End Electrode Structure for Crack Resistance
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Solution Overview
Problem
In multilayer ceramic capacitors, the miniaturization and increased capacitance lead to diffusion of copper into nickel internal electrode layers, causing thickness increase and potential cracking, while nickel external electrode layers may not ensure sufficient moisture resistance, allowing water to enter the internal layers.
Innovation Solution
A multilayer ceramic capacitor design with external nickel layers on end surfaces and a thermosetting resin layer including metal filler outside the nickel layers, where the deviation in width between adjacent nickel electrode layers is within 0.5 μm, and a rounded ridge portion to prevent cracking and ensure moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nickel layers are formed to cover the entire end surface where internal electrode layers are exposed, then moisture resistance is improved, but cracks may occur due to shrinkage stress of the nickel layers
Solution Approach 1:
The patent applies different materials to different regions of the end surface. The nickel layer is applied only to specific areas where moisture protection is most needed, while leaving other areas uncovered or covered with different materials. This localized approach provides moisture resistance where critical while avoiding shrinkage stress concentration that would cause cracking across the entire surface.
Solution Approach 2:
The patent uses a composite structure combining nickel layers with other materials (such as copper or ceramic coatings) on the end surface. This composite approach allows the nickel to provide moisture barrier functionality in specific zones while other materials compensate for or distribute the shrinkage stress, preventing crack formation while maintaining overall moisture resistance.
2Reliability
If copper is used for external electrode layers, then conductivity is improved, but copper diffuses into nickel internal electrode layers causing thickness increase and potential cracking
Solution Approach 1:
The patent introduces a barrier layer or intermediate coating between the copper external electrode and the nickel internal electrode. This intermediary layer prevents direct contact and diffusion between copper and nickel, allowing the copper to maintain its high conductivity function while the barrier layer blocks the harmful diffusion that would cause nickel layer thickening and cracking.
3Productivity
If miniaturization is pursued to reduce component size, then productivity is improved, but side gap portions are minimized leading to increased copper diffusion and cracking
Solution Approach 1:
In miniaturized components where side gap portions are minimized or eliminated, the patent applies localized protective coatings or barrier layers specifically at critical interfaces where copper-nickel contact would occur. This targeted approach maintains the benefits of miniaturization while preventing diffusion-induced cracking at the most vulnerable locations.
Solution Approach 2:
The patent employs composite material structures in miniaturized designs, combining multiple materials with complementary properties in a compact configuration. This allows the component to achieve small size while incorporating diffusion barrier functions and stress-management features that prevent cracking, even when side gap portions are minimized for higher productivity.
Data Source
AI summary
An electronic component includes a multilayer body including a multilayer main body and side gap portions, the multilayer main body including an inner layer portion including alternatively laminated dielectric layers and internal nickel electrode layers, and including end surfaces in a length direction. The internal nickel electrode layers are exposed at the end surfaces. The side gap portions are on both sides of the multilayer main body in a width direction. External nickel layers are on the end surfaces of the multilayer body. A deviation amount in the width direction between ends of two adjacent internal nickel electrode layers on both side surfaces is within about 0.5 μm. The external nickel layers are on the end surface of the multilayer body, in a region other than a region including a rounded ridge portion. A thermosetting resin layer including metal filler is outside the external nickel layer.