Dielectric Composition Ratios for Stable Thin-Layer MLCC Capacitance
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving high dielectric constants without compromising reliability and insulation resistance, especially when dielectric layers are thinned, leading to increased capacitance change rates with temperature and DC voltage.
Innovation Solution
A dielectric composition incorporating BaTiO3, (Ba,Ca)(Ti,Ca)O3, (Ba,Ca)(Ti,Zr)O3, or Ba(Ti,Zr)O3 as main components, with rare earth elements and variable/fixed valence acceptor elements, where the ratio of rare earth element content to acceptor element content is between 0.5 and 6.0, enhancing dielectric constants and reliability while minimizing grain growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dielectric layer thickness is reduced to achieve miniaturization and high capacity, then the number of layers can be increased, but the reliability deteriorates and insulation resistance decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric layer by incorporating specific ratios of barium titanate (40-70 wt%), calcium titanate (10-30 wt%), and zinc oxide (5-20 wt%), along with controlled amounts of bismuth oxide (0.1-5 wt%) and rare earth oxides (0.1-5 wt%). This compositional parameter optimization enables achieving high capacity in thinned dielectric layers while maintaining reliability through enhanced insulation resistance and controlled grain growth.
2Quantity of substance
If the dielectric constant is increased by grain growth to achieve high dielectric properties, then the dielectric constant increases, but the capacitance change rate with temperature and DC voltage increases and reliability decreases
Solution Approach 1:
The patent optimizes the grain size parameter to be within 0.5-5 μm through controlled sintering conditions and compositional design, preventing excessive grain growth. Simultaneously, the addition of zinc oxide (5-20 wt%) and bismuth oxide (0.1-5 wt%) modifies the dielectric properties to achieve high dielectric constant while suppressing the capacitance change rate with temperature and DC voltage, thereby maintaining reliability.
Solution Approach 2:
The patent creates a composite dielectric material system combining barium titanate, calcium titanate, zinc oxide, bismuth oxide, and rare earth oxides. This composite approach allows synergistic effects where the base ceramic provides high dielectric constant, zinc oxide suppresses grain boundary effects, bismuth oxide enhances insulation, and rare earth oxides stabilize the crystal structure, collectively achieving high dielectric properties with improved capacitance stability.
3Length of moving object
If the dielectric layer is thinned to increase layer count, then miniaturization is achieved, but the number of particles per dielectric layer decreases leading to reliability deterioration
Solution Approach 1:
The patent controls the grain size parameter within 0.5-5 μm and optimizes the sintering temperature and time parameters to ensure sufficient particle formation even in thinned dielectric layers. The compositional parameters, particularly the 40-70 wt% barium titanate combined with calcium titanate and zinc oxide, promote uniform and dense particle distribution, maintaining adequate particle count per layer despite reduced thickness.
Solution Approach 2:
The composite material system with multiple ceramic phases and oxides promotes the formation of fine, uniform grains throughout the dielectric layer. The zinc oxide and bismuth oxide components act as grain growth modifiers that prevent excessive coarsening, ensuring that even when the overall layer thickness is reduced, the particle density remains sufficient to maintain reliability.
4Quantity of substance
If high dielectric constant composition is designed by grain growth, then dielectric constant increases, but insulation resistance deteriorates
Solution Approach 1:
The patent optimizes the sintering temperature parameter to be within 900-1100°C and controls the sintering time to achieve complete reaction and densification without excessive grain growth. The compositional parameters, particularly the inclusion of zinc oxide (5-20 wt%) and bismuth oxide (0.1-5 wt%), fundamentally change the grain boundary properties to maintain high insulation resistance even when achieving high dielectric constant through controlled grain development.
Solution Approach 2:
The composite dielectric material incorporates zinc oxide and bismuth oxide as key components that specifically address the insulation resistance issue. Zinc oxide forms a protective grain boundary phase that maintains high insulation resistance, while bismuth oxide enhances the overall dielectric properties. This composite approach allows the material to achieve high dielectric constant through moderate grain growth while the grain boundary phases preserve insulation resistance.
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 solution effectively increases dielectric constants per grain size, improves insulation resistance, and reduces the impact of DC voltage on capacitance, maintaining high dielectric properties and reliability even with thin dielectric layers.
Implementation Method 1
a dielectric composition which implements high dielectric properties without deterioration of reliability even in a case in which a dielectric layer is thinned; a capacity reduction rate according to DC voltage is not increased
Implementation Method 2
a high dielectric constant is secured by simply causing the grain growth to adjust the number of dipoles in a crystal
Data Source
AI summary
A dielectric composition includes one of BaTiO3, (Ba,Ca)(Ti,Ca)O3, (Ba,Ca)(Ti,Zr)O3, Ba(Ti,Zr)O3 and (Ba,Ca)(Ti,Sn)O3, as a main component, a first subcomponent including a rare earth element, and a second subcomponent including at least one of a variable valence acceptor element and a fixed valence acceptor element. When a sum of contents of the rare earth element is defined as DT and a sum of contents of the variable valence acceptor element and the fixed valence acceptor element is defined as AT, (DT/AT)/(Ba+Ca) satisfies more than 0.5 and less than 6.0. In addition, a multilayer electronic component including the dielectric composition is provided.