MLCC Dielectric Grain Boundary Mg Control for Thin-Layer 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 challenge for securing the reliability of the dielectric layer, particularly in terms of insulation resistance and high-temperature reliability.
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 manufacturing method involving a reducing atmosphere sintering process to prevent the formation of a Ni—Mg—O secondary phase, ensuring even distribution of Mg at the grain boundary and enhancing 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 and miniaturization are improved, but the reliability and insulation resistance deteriorate due to increased electric field stress
Solution Approach 1:
The patent applies local quality by creating a non-uniform Mg distribution where the grain boundary region has significantly higher Mg content (3 times or more) than the crystal grain interior. This localized enrichment of Mg at grain boundaries specifically targets the regions where electrical breakdown typically initiates, providing enhanced insulation resistance and reliability at the critical interfaces without compromising the overall capacitance achieved through thin dielectric layers.
Solution Approach 2:
The patent employs composite material strategy by forming a distinct compositional structure within the dielectric layer, where regions of high Mg content at grain boundaries are combined with regions of lower Mg content in crystal grain interiors. This composite structure creates a heterogeneous material system that simultaneously achieves high capacitance through thin overall thickness while providing enhanced reliability through localized Mg-rich barriers at grain boundaries that resist electrical breakdown.
2Length of stationary object
If the thickness of the dielectric layer is reduced, then miniaturization is achieved, but the electric field strength increases causing deterioration of insulation resistance
Solution Approach 1:
The patent applies local quality by creating a non-uniform Mg distribution where the grain boundary region has significantly higher Mg content (3 times or more) than the crystal grain interior. This localized enrichment of Mg at grain boundaries specifically targets the regions where electrical breakdown typically initiates, providing enhanced insulation resistance and reliability at the critical interfaces without compromising the overall capacitance achieved through thin dielectric layers.
Solution Approach 2:
The patent uses Mg as an intermediary element that mediates between the conflicting requirements of thin dielectric thickness and high insulation resistance. By positioning Mg preferentially at grain boundaries, it acts as a barrier or mediator that blocks electrical breakdown paths along the grain boundaries, thereby maintaining insulation resistance even when the overall dielectric thickness is reduced for miniaturization.
3Reliability
If Mg content at grain boundary is increased to enhance grain boundary resistance, then reliability is improved, but the formation of Ni—Mg—O secondary phase may occur deteriorating the properties
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Mg content ratio between grain boundaries and crystal grains to be 3 times or more, while also controlling the absolute Mg content to be within a specific range (0.2-0.6 at% at grain boundaries). This parameter optimization ensures sufficient Mg enrichment to provide high grain boundary resistance and reliability, while simultaneously keeping the Mg content below the threshold that would trigger formation of harmful Ni-Mg-O secondary phases.
Solution Approach 2:
The patent applies local quality by creating a non-uniform Mg distribution where the grain boundary region has significantly higher Mg content (3 times or more) than the crystal grain interior. This localized enrichment of Mg at grain boundaries specifically targets the regions where electrical breakdown typically initiates, providing enhanced insulation resistance and reliability at the critical interfaces without compromising the overall capacitance achieved through thin dielectric layers.
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 when the dielectric layer thickness is 0.5 μm or less, and facilitates miniaturization and high capacitance while preventing excessive suppression of crystal grain growth.
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
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.