MLCC Dielectric Grain Structure for High-Frequency Capacitance
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Solution Overview
Problem
Existing multi-layered ceramic capacitors (MLCCs) face challenges in achieving high effective dielectric constants, high frequency performance, low electric field resistance, and reliable temperature characteristics due to non-uniform grain growth and size distribution of dielectric grains, particularly in smaller and more complex microstructures.
Innovation Solution
The development of a multi-layered capacitor with cube-shaped dielectric grains containing barium titanium oxide, controlled through precise manufacturing methods to ensure uniform grain growth and distribution, including a core-shell structure with specific compositions, achieving a sintering relative density of 98% and average grain sizes of 160 nm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of sintered dielectric grains of BaTiO3 is increased to achieve high dielectric constants, then the dielectric constant is improved, but the effective dielectric constant at high frequency and low electric field deteriorates
Solution Approach 1:
The patent changes the particle size parameter of dielectric grains to a specific range (100-200 nm) to optimize both dielectric constant and effective dielectric constant performance. This parameter optimization resolves the contradiction by finding the optimal grain size that balances high dielectric constant with high frequency and low electric field performance
Solution Approach 2:
The patent uses composite dielectric grains with a core-shell structure where the core contains BaTiO3 and the shell contains other dielectric materials. This composite structure enables simultaneous achievement of high dielectric constant from the BaTiO3 core and improved effective dielectric constant characteristics from the shell material
2Reliability
If the size of dielectric grains is reduced to improve effective dielectric constant, then high frequency performance is improved, but the dielectric constant deteriorates
Solution Approach 1:
The core-shell composite structure allows the small-sized core (100-200 nm) to provide high effective dielectric constant while the shell material contributes to maintaining high dielectric constant, thus resolving the contradiction between grain size reduction and dielectric constant maintenance
3Volume of moving object
If the microstructure is thinned to achieve smaller capacitor size, then the capacitor size is reduced, but the uniformity of grain growth and size distribution deteriorates
Solution Approach 1:
The patent applies preliminary actions during the sintering process, including controlled heating rates, holding times, and atmosphere control, to ensure uniform grain growth in thinned dielectric layers. These preliminary actions prevent non-uniform grain growth and maintain consistent grain size distribution even in reduced-thickness structures
Solution Approach 2:
The patent optimizes sintering parameters including temperature (900-1100°C), time (1-10 minutes), and atmosphere to achieve uniform grain growth in thinned structures. By precisely controlling these parameters, the patent maintains grain size uniformity while enabling smaller capacitor dimensions
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 enhances the effective dielectric constant, high frequency performance, low electric field resistance, and temperature reliability of MLCCs, ensuring improved integration and density of dielectric layers.
Implementation Method 1
achieving a sintering relative density of 98% and average grain sizes of 160 nm or less
Data Source
AI summary
A multi-layered capacitor including a capacitor body including a dielectric layer and an internal electrode, and an external electrode disposed outside the capacitor body, wherein the dielectric layer includes a plurality of dielectric grains, and the dielectric grains have a cube shape and include a core containing barium (Ba) and titanium (Ti) oxide.