Multilayer Ceramic Capacitor External Electrode Thickness Ratio
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Solution Overview
Problem
Multilayer ceramic capacitors (MLCCs) face challenges in reducing thickness to match thinner board cores without compromising strength, as excessive reduction leads to cracks due to sintering and plating stress, especially when the ceramic body thickness is below 80 μm.
Innovation Solution
The solution involves adjusting the ratios of the ceramic body thickness to the external electrode thickness, with a ratio of 0.18 or less, and the plated layer thickness to the external electrode thickness, with a ratio of 0.35 or more, to prevent crack generation while maintaining reliability, using a heat transfer method for forming external electrodes and ensuring the ceramic body thickness is 100 μm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the ceramic body is reduced to match thinner board cores, then the overall thickness of the MLCC is reduced, but the strength of the ceramic body decreases leading to cracks due to sintering shrinkage stress and plating stress
Solution Approach 1:
The patent applies parameter changes by establishing specific thickness ratio parameters (T1/T2 ≤ 0.18 and T1/Tp ≥ 0.35) to resolve the contradiction between reducing ceramic body thickness and maintaining its strength. By controlling these dimensional parameters, the patent prevents crack generation while enabling thinner MLCC designs that match modern board core thicknesses.
2Length of moving object
If the thickness of the ceramic body is reduced below 80 μm, then the overall size is reduced, but the generation frequency of cracks increases due to concentrated stress
Solution Approach 1:
The patent uses parameter changes by defining critical thickness ratios (T1/T2 ≤ 0.18 and T1/Tp ≥ 0.35) that prevent crack generation even when the ceramic body thickness is reduced below 80 μm. These parameter specifications ensure that stress is properly distributed, maintaining reliability while achieving reduced overall thickness.
3Strength
If the thickness of the external electrode is increased to strengthen the ceramic body, then crack generation is reduced, but the overall thickness of the MLCC increases
Solution Approach 1:
The patent resolves this contradiction through parameter changes by establishing the thickness ratio T1/T2 ≤ 0.18, which optimizes the relationship between external electrode thickness (T1) and ceramic body thickness (T2). This parameter control allows the external electrode to provide sufficient strength support while keeping the overall MLCC thickness reduced to match thin board cores.
Solution Approach 2:
The patent applies composite materials by combining the external electrode material with the ceramic body in a specifically optimized structural configuration. The controlled thickness ratios create a composite structure where the external electrode reinforces the ceramic body without excessive thickness increase, achieving both strength and compactness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces crack generation in the ceramic body without degrading reliability, as demonstrated by experimental results showing no cracks in samples with adjusted thickness ratios, maintaining the ceramic body's integrity and performance.
Implementation Method 1
forming first and second external electrodes on both end surfaces of the ceramic body
Data Source
AI summary
There is provided a multilayer ceramic capacitor including: a ceramic body in which a plurality of dielectric layers are laminated; a plurality of first and second internal electrodes formed to be alternately exposed to both end surfaces of the ceramic body with the dielectric layer interposed therebetween; and first and second external electrodes formed on both end surfaces of the ceramic body and electrically connected to the first and second internal electrodes, wherein when it is defined that a thickness of a band of the first and second external electrodes is T1 and a thickness of the ceramic body is T2, a ratio (T1/T2) of the thickness of the band of the first or second external electrode to the thickness of the ceramic body is equal to or less than 0.18.