Multilayer Ceramic Capacitor Base Metal Diffusion Control
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Solution Overview
Problem
Existing multilayer ceramic capacitors face issues with permittivity decrease due to non-uniform base metal concentration in dielectric layers, leading to capacitance variability and anomalies, as the base metal is not evenly distributed between internal electrodes.
Innovation Solution
A multilayer ceramic capacitor design with a uniform base metal concentration across five regions between internal electrodes, achieved by ensuring the base metal is diffused uniformly throughout the dielectric layer, with internal electrodes having a thickness of 0.2 μm or greater to maintain a stable concentration gradient, thereby preventing permittivity decrease and capacitance anomalies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the base metal is not diffused in the middle portion of the dielectric layer in the stacking direction, then the manufacturing process is simplified, but the concentration of the base metal becomes partially high in the stacking direction, decreasing the permittivity of the dielectric layer
Solution Approach 1:
The patent changes the diffusion parameters by specifying that the base metal concentration in each of five regions (obtained by dividing the dielectric layer equally into five in the stacking direction) should be within ±20% of the average concentration. This parameter control ensures uniform diffusion throughout the dielectric layer, including the middle portion, thereby maintaining high permittivity while keeping the manufacturing process feasible.
Solution Approach 2:
The patent applies local quality control by dividing the dielectric layer into five specific regions in the stacking direction and controlling the base metal concentration in each region individually. This ensures that the middle portion of the dielectric layer also receives adequate base metal diffusion, preventing localized high concentration areas that would decrease permittivity.
2Volume of moving object
If the internal electrode thickness is reduced to achieve small-sized capacitors, then the device size is reduced, but the base metal diffusion becomes insufficient, leading to non-uniform concentration distribution
Solution Approach 1:
The patent specifies that the internal electrode thickness should be 0.2 μm or greater to ensure sufficient base metal diffusion. This parameter setting balances the need for small-sized capacitors with the requirement for uniform base metal concentration distribution, preventing insufficient diffusion that would lead to non-uniform concentration and permittivity degradation.
3Quantity of substance
If the number of stacked dielectric layers is increased to achieve large capacity, then the electrostatic capacitance is increased, but the concentration control of base metal becomes more difficult, increasing capacitance variability
Solution Approach 1:
The patent controls the base metal concentration parameter by requiring it to be within ±20% of the average in each of the five regions of every dielectric layer. This standardized parameter control across all stacked layers ensures consistent permittivity and reduces capacitance variability, enabling reliable large-capacity capacitors through increased layer stacking.
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 uniform base metal distribution stabilizes capacitance, reduces capacitance variability, and prevents anomalies by ensuring the base metal concentration remains within ±20% of the average across the dielectric layer, enhancing the reliability and performance of the multilayer ceramic capacitors.
Implementation Method 1
the base metal is diffused uniformly throughout the dielectric layer
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 pair 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 thicknesses of the first internal electrode and the second internal electrode are 0.2 μm or greater.