Multilayer Ceramic Capacitor Structure for Moisture-Resistant Densification
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Solution Overview
Problem
Multilayer ceramic electronic devices face challenges in achieving adequate moisture resistance and reliability due to diffusion issues between the capacity section and side margins, where additives like silicon or manganese can degrade the dielectric constant and cause abnormal grain growth when used to promote densification.
Innovation Solution
A multilayer ceramic device design with a perovskite structure ceramic material, where the side margins have a higher Ba/Ti ratio than the capacity section, and an intermediate portion with a lower Ba/Ti ratio than the capacity section, to control densification temperature and prevent barium diffusion, thereby enhancing moisture resistance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additives like silicon or manganese are added to side margins to promote densification, then moisture resistance is improved, but dielectric constant decreases and abnormal grain growth occurs in the capacity section
Solution Approach 1:
The device is divided into three distinct regions with different A/B ratios: side margins (higher A/B ratio), capacity section (standard A/B ratio), and intermediate portions (lower A/B ratio). This segmentation allows each region to have optimized properties - side margins achieve densification without additives, capacity section maintains dielectric constant, and intermediate portions prevent abnormal grain growth
Solution Approach 2:
Different A/B ratios are assigned to different regions of the multilayer ceramic device. The side margins have a higher A/B ratio to promote densification and moisture resistance, while the capacity section maintains a standard A/B ratio to preserve dielectric constant. This local differentiation of material properties resolves the contradiction between moisture resistance and dielectric performance
2Manufacturing precision
If barium diffusion is allowed during firing, then densification is achieved, but abnormal grain growth occurs in the capacity section
Solution Approach 1:
Intermediate portions with lower A/B ratio act as buffer zones between the side margins and capacity section. These intermediate regions control the diffusion of barium during firing, allowing densification to proceed while preventing excessive barium accumulation in the capacity section that would cause abnormal grain growth
Solution Approach 2:
The A/B ratio parameter is strategically varied across different regions: higher in side margins to enable densification at controlled temperatures, and lower in intermediate portions to regulate barium diffusion and prevent abnormal grain growth in the capacity section during the firing process
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 configuration improves moisture resistance and reliability by lowering the densification temperature of side margins and suppressing abnormal grain growth in the capacity section, maintaining the dielectric constant and extending the lifespan of the multilayer ceramic capacitor.
Implementation Method 1
lowering the densification temperature of side margins
Implementation Method 2
prevent barium diffusion
Data Source
AI summary
A multilayer ceramic device includes a multilayer chip. The multilayer chip has a capacity section, a side margin and an intermediate portion. The intermediate portion is provided between the capacity section and the side margin. An A/B ratio is larger in the side margin than in the capacity section, and is smaller in the intermediate portion than in the capacity section.