Multilayer Ceramic Capacitor Dielectric for Thin-Layer Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in achieving a reduction in size and increase in capacitance while maintaining reliability due to the influence of fine defects in dielectric layers, leading to insulation resistance reduction and insulation breakdown.
Innovation Solution
The use of dielectric particles with a core-shell structure and controlled intra-particle concentration distribution, along with a specific ratio of core-shell and uniform solid solution particles, enhances dielectric constant and insulation resistance, improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric layer is thinned to reduce size and increase capacitance, then the capacitance per unit volume increases, but the insulation resistance decreases and insulation breakdown occurs due to increased electric field strength and fine defects
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell portion has a different composition (higher concentration of sub-components like rare earth elements) than the core portion. This localized compositional variation allows the shell to provide enhanced insulation resistance at the particle surface where electric field stress is highest, while the core maintains the dielectric constant. This resolves the contradiction by making different regions of the dielectric particle serve different functions: the core optimizes capacitance while the shell protects against insulation breakdown.
2Length of moving object
If the dielectric layer is thinned to reduce size, then the device dimensions are reduced, but the electric field strength per layer increases causing insulation breakdown
Solution Approach 1:
The patent employs composite materials by combining two types of dielectric particles: core-shell particles (with concentrated sub-components in the shell) and uniform solid solution particles (with evenly distributed sub-components). This composite approach allows the dielectric layer to simultaneously achieve high insulation strength (through the shell particles' surface enrichment) and high dielectric constant (through the uniform particles' even distribution), thereby maintaining insulation strength even when the layer is thinned for miniaturization.
3Reliability
If sub-components are dissolved with high concentration in the shell portion to improve reliability, then the insulation resistance improves, but the manufacturing complexity increases due to concentration gradient control
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of sub-components (such as rare earth elements) in different regions of the dielectric particle. The shell portion has a higher concentration parameter of sub-components compared to the core portion. This parameter variation is achieved through controlled sintering processes and raw material preparation, allowing the formation of the core-shell structure with specific concentration gradients that enhance reliability without requiring overly complex manufacturing steps.
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 results in multilayer ceramic capacitors that are reduced in size, increased in capacitance, and exhibit excellent reliability by minimizing insulation resistance degradation and leakage current.
Implementation Method 1
the shell portion includes sub-components dissolved with a concentration higher than that in the core portion... increase a dielectric constant
Implementation Method 2
increase insulation resistance... minimize insulation resistance degradation and leakage current
Data Source
AI summary
A multilayer ceramic capacitor includes an element body portion and a pair of outer electrodes on first and second end surfaces and connected to inner electrode layers. The element body portion includes first and second side margin portions, and first and second outer layer portions, and an inner layer portion. A dielectric includes dielectric particles including barium and titanium, and, as sub-components, rare earth elements, and one or more first additional elements. In a cross section crossing a center in a length direction, dielectric layers included in an inner layer portion include core-shell particles and uniform solid solution particles. A ratio of average areas occupied by the core-shell particles and the uniform solid solution particles is about 0.8 to about 1.5, and a coefficient of variation of a first additional element concentration in the uniform solid solution particles is equal to or less than about 20%.