Ceramic Electronic Component Grain Boundary Mg Control for MLCC Reliability
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Solution Overview
Problem
As multilayer ceramic capacitors (MLCCs) are miniaturized and their dielectric layers thinned to increase capacitance, the electric field applied to the dielectric layer at the same operating voltage increases, posing a reliability challenge due to reduced insulation resistance and high temperature sensitivity, which existing technologies struggle to address effectively.
Innovation Solution
A ceramic electronic component with a dielectric layer containing a plurality of crystal grains and a grain boundary, where the Mg content of the grain boundary is 3 or more times that of the crystal grains, and a sintering process in a reducing atmosphere with controlled electromotive force to prevent Ni—Mg—O secondary phase formation, ensuring even Mg distribution and enhanced grain boundary resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the dielectric layer is reduced to achieve miniaturization and high capacitance, then the capacitance increases, but the insulation resistance deteriorates and reliability decreases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the grain boundary region has a different MgO concentration (higher) compared to the crystal grain interior (lower). This localized enhancement of MgO at grain boundaries specifically improves insulation resistance without affecting the overall capacitance, thereby resolving the contradiction between miniaturization and reliability maintenance.
Solution Approach 2:
The patent changes the chemical composition parameter by precisely controlling the MgO content distribution - setting it to 0.01-0.05 wt% in crystal grains and 0.05-0.15 wt% at grain boundaries. This parameter optimization ensures that even in thinned dielectric layers, the grain boundary resistance remains sufficiently high to maintain insulation resistance and reliability.
2Quantity of substance
If the thickness of the dielectric layer is reduced to achieve miniaturization, then the capacitance increases, but the electric field strength increases causing reliability deterioration
Solution Approach 1:
The patent addresses the increased electric field strength by creating local quality enhancement at grain boundaries through higher MgO concentration (0.05-0.15 wt%). This localized modification increases the breakdown voltage and resistance to electric field stress at the most vulnerable regions (grain boundaries), thereby maintaining reliability even when the dielectric layer is thinned to increase capacitance.
Solution Approach 2:
The patent applies beforehand cushioning by pre-introducing MgO at grain boundaries before the dielectric layer is subjected to high electric fields. This preventive measure creates a protective barrier that cushions against the harmful effects of high electric field strength, preventing premature breakdown and maintaining reliability in thinned structures.
3Reliability
If the Mg content at grain boundaries is increased to improve insulation resistance, then the grain boundary resistance increases, but Ni—Mg—O secondary phase formation occurs deteriorating reliability
Solution Approach 1:
The patent resolves this contradiction by precisely optimizing the MgO concentration parameters - maintaining it at 0.01-0.05 wt% in crystal grains and 0.05-0.15 wt% at grain boundaries. This controlled parameter range is sufficient to enhance grain boundary resistance and insulation properties while remaining below the threshold that would trigger Ni-Mg-O secondary phase formation, thus avoiding reliability deterioration.
Solution Approach 2:
The patent applies partial action by introducing MgO only at the grain boundaries (0.05-0.15 wt%) rather than uniformly throughout the entire dielectric layer. This localized approach provides the necessary insulation enhancement at critical regions without excessive MgO content that would lead to secondary phase formation, thereby maintaining reliability while improving insulation resistance.
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 improves the reliability and insulation resistance of the ceramic electronic component, maintaining reliability even at reduced dielectric layer thicknesses, and enhances high-temperature performance by effectively controlling grain boundary resistance and preventing Ni—Mg—O secondary phase formation.
Implementation Method 1
sintering the stack body in a reducing atmosphere and re-oxidizing the sintered stack body in an oxidizing atmosphere
Implementation Method 2
re-oxidizing the sintered stack body in an oxidizing atmosphere
Implementation Method 3
sintering the stack body in a reducing atmosphere with controlled electromotive force to prevent Ni—Mg—O secondary phase formation
Data Source
AI summary
A ceramic electronic component includes a body including a dielectric layer and an internal electrode; and an external electrode disposed on the body and connected to the internal electrode. The dielectric layer includes a plurality of crystal grains and a grain boundary disposed between adjacent crystal grains. A ratio (C2/C1) of an Mg content (C2) of the grain boundary to an Mg content (C1) of at least one of the plurality of crystal grains is 3 or more.