MLCC Side Margin Composition for Thin-Margin Crack Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving sufficient strength and insulation properties due to weak side margin portions, which are prone to cracking and water ingress when dimensions are reduced for smaller sizes.
Innovation Solution
The capacitors incorporate side margin layers with varying silicon content, where the layer closest to the internal electrode has a lower silicon content than others, and a silicon to titanium mole ratio of 1.0 to 7.0, along with a thickness of 5 μm to 40 μm, to enhance strength and prevent cracking and water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of side margin portions is reduced to achieve higher capacitance in smaller size, then the capacitance density improves, but the deflecting strength of side margin portions becomes insufficient
Solution Approach 1:
The patent applies local quality by creating side margin portions with non-uniform silicon content distribution. The side margin portions adjacent to internal electrodes have lower silicon content (1-5 mass%) while other side margin portions have higher silicon content (6-10 mass%). This localized variation in material composition allows the region near internal electrodes to maintain flexibility and bonding strength, while other regions provide overall structural support, thereby achieving sufficient deflecting strength even when overall thickness is reduced for higher capacitance density.
2Volume of moving object
If the thickness of side margin portions is reduced, then the capacitor size decreases, but the side margin portions become more prone to cracking and chipping
Solution Approach 1:
The patent implements local quality by differentiating silicon content in different regions of side margin portions. The reduced-thickness regions maintain structural integrity through higher silicon content (6-10 mass%) in non-critical areas, while critical regions adjacent to internal electrodes use lower silicon content (1-5 mass%) to maintain flexibility. This spatially varying composition prevents cracking and chipping throughout the structure even when overall dimensions are reduced.
Solution Approach 2:
The patent employs composite materials by creating a heterogeneous structure within the side margin portions. Different silicon content zones (1-5 mass% near internal electrodes, 6-10 mass% elsewhere) effectively create a composite ceramic material with spatially varying properties. This composite approach allows the side margin portions to simultaneously achieve reduced thickness for smaller size while maintaining resistance to cracking and chipping through the synergistic combination of flexible and rigid regions.
3Quantity of substance
If the side margin portions are made thinner, then the capacitance increases, but water ingress from cracks or chips increases, decreasing insulation properties
Solution Approach 1:
The patent applies local quality by positioning lower silicon content (1-5 mass%) specifically in side margin portions adjacent to internal electrodes, where electrical fields are strongest and stress concentration is highest. This localized composition creates a more flexible, crack-resistant zone that prevents water ingress pathways. Other side margin portions with higher silicon content (6-10 mass%) provide additional barrier protection. This spatially differentiated approach maintains insulation properties even when overall side margin thickness is reduced to increase capacitance.
Data Source
AI summary
A multilayer ceramic capacitor includes a laminated body and first and second external electrodes respectively on both end surfaces of the laminated body. When regions where first internal electrodes or second internal electrodes are not present are regarded as side margin portions in a cross section of the laminated body as viewed from the laminating direction, the side margin portions include multiple side margin layers, and the content of Si in the side margin layer closest to the internal electrode is lower than that in the side margin layer other than the side margin layer closest to the internal electrode.