MLCC Core-Shell Grain Structure for Dielectric and Withstand Balance
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Solution Overview
Problem
Conventional methods for improving the dielectric constant and voltage withstand characteristics of multilayered capacitors face limitations due to the need for smaller dielectric grains, which compromises performance, and controlling defect behaviors in dielectric layers is challenging, especially with barium titanate-based ceramics.
Innovation Solution
A multilayered capacitor design incorporating dielectric grains with a core-shell structure, where the core-to-diameter ratio is controlled between 60% to 80%, and the grains are composed of barium titanate-based compounds with specific subcomponents, using a liquid metal oxide additive to maintain optimal core fraction and uniform distribution, enhancing dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric grain size is increased to increase the dielectric constant, then the dielectric constant increases, but the voltage withstand characteristics and high temperature characteristics deteriorate due to grain ratio decrease and shell ratio increase
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core region and shell region have different compositions and properties. The core contains barium titanate-based ceramic powder with specific additives to achieve high dielectric constant, while the shell has controlled composition to maintain voltage withstand characteristics. This allows different regions of the same dielectric grain to have optimized properties for their specific functions.
Solution Approach 2:
The patent uses composite materials by combining barium titanate-based ceramic powder with specific additives (rare earth materials as donnors and acceptors) to create a core-shell structured dielectric grain. The core and shell are composed of different material combinations, with the core optimized for dielectric constant and the shell for voltage withstand, achieving synergistic performance improvement.
2Reliability
If the particle size is reduced to maintain voltage withstand characteristics, then the voltage withstand characteristics improve, but the dielectric constant decreases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core region and shell region have different compositions and properties. The core contains barium titanate-based ceramic powder with specific additives to achieve high dielectric constant, while the shell has controlled composition to maintain voltage withstand characteristics. This allows different regions of the same dielectric grain to have optimized properties for their specific functions.
Solution Approach 2:
The patent uses composite materials by combining barium titanate-based ceramic powder with specific additives (rare earth materials as donnors and acceptors) to create a core-shell structured dielectric grain. The core and shell are composed of different material combinations, with the core optimized for dielectric constant and the shell for voltage withstand, achieving synergistic performance improvement.
3Quantity of substance
If the core fraction is increased to improve dielectric constant, then the dielectric constant increases, but the shell fraction decreases which may compromise voltage withstand characteristics
Solution Approach 1:
The patent applies parameter changes by precisely controlling the core-to-dielectric grain diameter ratio to be between 60-80%, and controlling the diameter of dielectric grains to be 300-500 nm with core diameter of 200-400 nm. These specific parameter ranges optimize both the dielectric constant (through adequate core fraction) and voltage withstand characteristics (through sufficient shell fraction), resolving the contradiction between the two performance metrics.
4Volume of moving object
If MLCC size is reduced to achieve smaller and thinner capacitors, then the miniaturization is achieved, but the dielectric grain development is limited
Solution Approach 1:
The patent applies parameter changes by precisely controlling the core-to-dielectric grain diameter ratio to be between 60-80%, and controlling the diameter of dielectric grains to be 300-500 nm with core diameter of 200-400 nm. These specific parameter ranges optimize both the dielectric constant (through adequate core fraction) and voltage withstand characteristics (through sufficient shell fraction), resolving the contradiction between the two performance metrics.
Data Source
AI summary
Provided are a multilayered capacitor and a manufacturing method thereof, the multilayered capacitor including a capacitor body including a dielectric layer and an internal electrode, and an external electrode outside the capacitor body, wherein the dielectric layer includes a plurality of dielectric grains, at least one of the plurality of dielectric grains has a core-shell structure, and in the dielectric grains having the core-shell structure, a ratio of a diameter of the core to a diameter of the dielectric grain having the core-shell structure is about 60% to about 80%.