Multilayer Ceramic Capacitor Side Margin for Stable Sintering
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Solution Overview
Problem
The miniaturization and increased capacity of multilayer ceramic capacitors lead to thinner dielectric and internal electrode layers, making it difficult to ensure stability during sintering, and result in oversintering of the capacity section, shortening the life and compromising reliability due to metal component diffusion and spheroidization.
Innovation Solution
A multilayer ceramic electronic device with a side margin composed of ceramic material containing boron and silicon, where the boron concentration gradually decreases from the capacity section to the outside, promoting densification while suppressing oversintering, and silicon segregation increases at the surface to prevent moisture intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If dielectric layers and internal electrode layers are made thinner to achieve miniaturization and increased capacity, then the capacitor size is reduced and capacity is increased, but sintering stability deteriorates and oversintering occurs
Solution Approach 1:
The patent applies local quality by creating a side margin region with different chemical composition (higher B2O3 and SiO2 content) compared to the capacity section. This localized compositional difference provides enhanced sintering stability and moisture resistance specifically where needed (at the sides and ends) without affecting the overall miniaturization and capacity of the capacitor.
2Ease of manufacture
If conventional uniform dielectric composition is used, then manufacturing is simple, but oversintering and spheroidization occur leading to shortened life
Solution Approach 1:
The patent introduces a side margin with localized high B2O3 and SiO2 content to prevent oversintering and spheroidization of internal electrodes. This local compositional modification extends capacitor life by maintaining structural integrity during sintering, while the rest of the capacitor maintains conventional structure for ease of manufacture.
Solution Approach 2:
The patent changes the chemical composition parameters of the dielectric layer by adding B2O3 (0.1-5 wt%) and SiO2 (0.1-5 wt%) specifically in the side margin region. This parameter change enhances sintering stability and prevents harmful spheroidization, thereby extending capacitor operational life.
3Reliability
If capacity section is densely sintered, then capacitance performance is improved, but metal component diffusion increases and reliability decreases
Solution Approach 1:
The side margin acts as an intermediary barrier between the capacity section and the external environment. With high B2O3 and SiO2 content, it forms a protective layer that prevents moisture intrusion and metal component diffusion, allowing the capacity section to be densely sintered for optimal performance without suffering from harmful diffusion effects.
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
The device achieves enhanced moisture resistance and reliability by ensuring appropriate boron concentration gradients and silicon segregation, preventing oversintering and spheroidization, thus maintaining structural integrity and performance.
Implementation Method 1
a segregation degree of silicon in the second section is larger than a segregation degree of silicon in the first section
Implementation Method 2
firing the unfired multilayer chip
Data Source
AI summary
A multilayer ceramic electronic device includes a multilayer chip. The multilayer chip has a capacity section and a side margin. The side margin includes boron and silicon, and includes a first section and a second section in order from the capacity section side toward outside. A boron concentration of the first section is larger than a boron concentration of the second section. A segregation degree of silicon in the second section is larger than a segregation degree of silicon in the first section.