MLCC Side Margin Sn Composition for Crack Resistance
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Solution Overview
Problem
Miniaturized and high-capacitance multilayer ceramic capacitors face challenges in impact resistance and crack resistance due to reduced thickness and area of side margin portions, which increases the risk of breakage and cracks from external impacts.
Innovation Solution
Incorporating a higher content of tin (Sn) in the side margin portions compared to the dielectric layer, with the side margin portions containing 0.1 to 3.0 mol of Sn based on 100 mol of BaTiO3, to enhance toughness and moisture resistance, while maintaining a thickness of 15 μm or less to maximize the overlapping region of internal electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the side margin portion thickness and area are reduced to maximize internal electrode area, then the capacitance increases, but the impact resistance and crack resistance deteriorate
Solution Approach 1:
The patent applies different material compositions to different regions: the side margin portion contains 0.1 to 3.0 mol of Sn based on 100 mol of BaTiO3, while the active portion has lower or no Sn content. This local differentiation allows the side margin to have enhanced toughness and crack resistance without affecting the capacitance-forming active region.
Solution Approach 2:
The patent creates a composite structure where the side margin portion is formed by a different material composition (higher Sn content) than the active portion. This composite approach allows each region to have optimized properties: the side margin provides mechanical strength and crack resistance, while the active portion maximizes capacitance.
2Quantity of substance
If the side margin portion thickness and area are reduced to maximize internal electrode area, then the capacitance increases, but the reliability under external impacts deteriorates
Solution Approach 1:
The patent applies different material compositions to different regions: the side margin portion contains 0.1 to 3.0 mol of Sn based on 100 mol of BaTiO3, while the active portion has lower or no Sn content. This local differentiation allows the side margin to have enhanced toughness and crack resistance without affecting the capacitance-forming active region.
Solution Approach 2:
The patent creates a composite structure where the side margin portion is formed by a different material composition (higher Sn content) than the active portion. This composite approach allows each region to have optimized properties: the side margin provides mechanical strength and crack resistance, while the active portion maximizes capacitance.
3Strength
If the Sn content in side margin portions is increased to improve toughness and crack resistance, then the impact resistance improves, but the manufacturing complexity increases
Solution Approach 1:
The patent controls the Sn content parameter within a specific range (0.1 to 3.0 mol based on 100 mol of BaTiO3) to achieve the optimal balance between toughness and manufacturability. This parameter optimization ensures sufficient crack resistance while avoiding excessive manufacturing complexity.
Data Source
AI summary
A multilayer ceramic capacitor includes a ceramic body having a dielectric layer, a plurality of internal electrodes disposed in the ceramic body, and a first side margin portion and a second side margin portion arranged on end portions of the internal electrodes exposed through respective opposing surfaces of the ceramic body. The ceramic body includes an active portion having the plurality of internal electrodes arranged to overlap each other with the dielectric layer interposed therebetween to form capacitance, and cover portions disposed above an uppermost and below a lowermost internal electrode of the active portion. The first and second side margin portions include tin (Sn), and a content of Sn included in the first and second side margin portions is greater than a content of Sn included in the dielectric layer of the active portion.