Multilayer Ceramic Capacitor Uniform Base Metal Diffusion
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Solution Overview
Problem
Existing multilayer ceramic capacitors face a decrease in permittivity due to non-uniform base metal concentration in dielectric layers, leading to capacitance variability and anomalies, as the base metal is not adequately diffused throughout the stacking direction.
Innovation Solution
A multilayer ceramic capacitor design with a dielectric layer thickness of 0.6 μm or less, where the base metal concentration is maintained within ±20% of the average across five regions between internal electrodes, ensuring uniform Ni distribution and preventing high concentration areas that decrease permittivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric layer is thinned to achieve small-sized large-capacity capacitors, then the capacitance increases and size decreases, but the base metal concentration becomes non-uniform in the stacking direction, causing permittivity to decrease
Solution Approach 1:
The patent applies parameter changes by precisely controlling the diffusion depth of base metal (Ni) into the dielectric layer. By adjusting the diffusion distance to be 3 to 30% of the dielectric layer thickness, the patent achieves uniform base metal concentration distribution while maintaining thin dielectric layer dimensions (0.6 μm or less), thereby resolving the contradiction between achieving high capacitance through thinning and maintaining compositional uniformity.
2Stability of the object's composition
If base metal is diffused into the dielectric layer to improve temperature characteristic of capacitance, then temperature stability improves, but base metal concentration becomes non-uniform in the stacking direction, decreasing permittivity
Solution Approach 1:
The patent resolves this contradiction by changing the diffusion parameter - specifically controlling the diffusion depth to be 3 to 30% of the dielectric layer thickness. This parameter optimization allows the base metal to be sufficiently diffused to improve temperature characteristics while preventing excessive concentration that would decrease permittivity, thus achieving both temperature stability and high reliability.
Solution Approach 2:
The patent applies local quality by creating a controlled gradient of base metal concentration within the dielectric layer. Rather than uniform distribution, the diffusion is localized to specific depth regions (3-30% from the electrode interface), providing different functional zones: a diffusion zone for temperature stability and a bulk zone for maintaining high permittivity.
3Quantity of substance
If the dielectric layer thickness is reduced to 0.6 μm or less, then the capacitance density increases, but manufacturing precision requirements increase to maintain uniform base metal concentration
Solution Approach 1:
The patent addresses this contradiction through parameter changes in the diffusion process. By setting the diffusion depth to 3-30% of the dielectric layer thickness and controlling the diffusion distance to 50 nm or less from the electrode surface, the patent achieves uniform base metal concentration even in ultra-thin dielectric layers (0.6 μm or less), thereby enabling high capacitance density without excessive manufacturing precision requirements.
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 design stabilizes capacitance and reduces capacitance anomalies by ensuring uniform Ni distribution, maintaining capacitance within the normal distribution range and preventing unexpected drops, thereby enhancing the reliability of multilayer ceramic capacitors.
Implementation Method 1
a base metal is not diffused in the middle portion of the dielectric layer in the stacking direction
Data Source
AI summary
A multilayer ceramic capacitor includes: a pair of external electrodes; a first internal electrode containing a base metal and coupled to one of the external electrodes; a dielectric layer stacked on the first internal electrode and containing a ceramic material and the base metal; and a second internal electrode stacked on the dielectric layer, containing the base metal, and coupled to another one of the external electrodes, wherein a concentration of the base metal in each of five regions, which are equally divided regions of a region between locations 50 nm away from the first and second internal electrodes in a stacking direction between the first and second internal electrodes, is within ±20% of an average of the concentrations of the base metal in the five regions, and the dielectric layer has a thickness of 0.6 μm or less.