Multilayer Ceramic Capacitor External Electrode Segmentation
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Solution Overview
Problem
Multilayer ceramic capacitors (MLCCs) face challenges in achieving high capacitance and reliability while being miniaturized for use in smaller and thinner electronic devices, with existing external electrodes experiencing poor adhesion to the body and plating layers, leading to issues with solderability and mounting reliability.
Innovation Solution
The MLCC design includes a body with first and second external electrodes, where the first electrode layer is rich in ceramics for enhanced adhesion and the second electrode layer has a lower ceramic content for improved conductivity and uniform plating, allowing for excellent adhesion with both the body and plating layers, and the internal electrodes are connected through conductive layers penetrating the body to increase capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer external electrode structure is used, then the manufacturing process is simple, but the adhesion to both the body and plating layer is poor
Solution Approach 1:
The external electrode is divided into two distinct layers: a first external electrode layer with high ceramic content for strong adhesion to the body, and a second external electrode layer with lower ceramic content for excellent adhesion to the plating layer. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between manufacturing simplicity and adhesion reliability.
Solution Approach 2:
The external electrode uses a composite structure with two layers having different ceramic and metal compositions. The first layer contains ceramics and metal with a ceramic-to-metal ratio of 3:7 to 7:3, while the second layer has a ratio of 1:9 to 9:1. This composite material approach enables simultaneous optimization of body adhesion and plating layer adhesion.
2Volume of moving object
If the MLCC is miniaturized to meet device size requirements, then the device dimensions are reduced, but the capacitance and reliability are compromised
Solution Approach 1:
The invention changes the compositional parameters of the external electrode layers, specifically the ceramic-to-metal ratios in each layer. This parameter optimization enables better adhesion and electrical properties, allowing the MLCC to achieve high capacitance and reliability even in miniaturized dimensions. The first layer uses a 3:7 to 7:3 ratio while the second layer uses a 1:9 to 9:1 ratio.
Data Source
AI summary
A multilayer ceramic capacitor includes a body a first internal electrode and a second internal electrode disposed with a dielectric layer interposed therebetween, a first connecting electrode connected to the first internal electrode through the body, a second connecting electrode connected to the second internal electrode through the body, a first external electrode disposed on one surface of the body and connected to the first connecting electrode, and a second external electrode disposed on one surface of the body, spaced apart from the first external electrode, and connected to the second connecting electrode, wherein the first and second external electrodes each include a first electrode layer disposed on the body and including ceramics, and a second electrode layer disposed on the first electrode layer and having the content of ceramics smaller than that of the first electrode layer.