Multilayer Ceramic Capacitor Margin Region Composition for Sintering Control
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Solution Overview
Problem
Existing multilayer ceramic capacitors face issues with contraction differences between capacity and margin regions during sintering, leading to potential cracking and degraded humidity resistance due to insufficient reduction of contraction differences.
Innovation Solution
A multilayer ceramic capacitor design with a lower concentration of rare earth elements and higher total concentration of Si and B in margin regions compared to the capacity region, along with specific sintering additives, to reduce sintering temperature and minimize contraction differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the concentration of rare earth element in margin regions is increased to reduce contraction difference, then sintering temperature is reduced, but the concentration of rare earth element in capacity region may be compromised affecting capacitor performance
Solution Approach 1:
The patent applies local quality by creating different rare earth element concentrations in different regions of the multilayer ceramic capacitor. The margin regions have a first concentration of rare earth element (0.01-5 wt%) while the capacity region has a second concentration (0.003-0.5 wt%), allowing optimized sintering in margin regions without compromising the electrical performance of the capacity region.
Solution Approach 2:
The patent segments the ceramic body into distinct functional regions: margin regions that require lower sintering temperature and higher rare earth content for crack prevention, and capacity regions that require lower rare earth content for optimal electrical performance. This segmentation allows each region to be independently optimized.
2Temperature
If sintering additives are added to reduce sintering temperature, then contraction difference is reduced, but the composition complexity increases
Solution Approach 1:
The patent uses parameter changes by adjusting the concentration of sintering additives (Si and B totaling 0.003-5 wt%) and rare earth elements in the green sheet composition. These controlled compositional changes enable lower sintering temperatures while maintaining manageable formulation complexity through defined concentration ranges.
3Strength
If the sintering temperature is reduced to minimize contraction difference, then cracking is reduced, but the density and mechanical strength may be compromised
Solution Approach 1:
The patent introduces sintering additives (Si and B) as intermediary substances that facilitate sintering at lower temperatures. These additives act as mediators that promote densification and grain growth at reduced temperatures, enabling crack prevention through uniform contraction while maintaining adequate density and mechanical strength.
Solution Approach 2:
The patent achieves adequate sintering density at lower temperatures by optimizing multiple parameters simultaneously: sintering temperature (800-1300°C), sintering time (0.1-10 hours), and additive concentrations (Si: 0.003-5 wt%, B: 0.003-5 wt%). This multi-parameter optimization enables lower temperature processing without sacrificing density.
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 stress-induced cracking and enhances humidity resistance by ensuring uniform contraction across different regions, improving the overall performance and reliability of the multilayer ceramic capacitors.
Implementation Method 1
contraction during a sintering may delay, compared to the capacity region
Data Source
AI summary
A multilayer ceramic capacitor includes: a multilayer structure in which each of a plurality of ceramic dielectric layers and each of a plurality of internal electrode layers are alternately stacked wherein: a concentration of a rare earth element of at least one of an end margin region and a side margin region is lower than that of a capacity region; a total concentration of Si and B of the at least one of the end margin region and the side margin region is higher than that of the capacity region.