Multilayer Capacitor Electrode Composition for Low Leakage
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Solution Overview
Problem
The challenge is to improve the reliability and connectivity of multilayer ceramic capacitors while minimizing the decrease in capacitance due to the addition of Sn, which causes rapid shrinkage and thickness increase during sintering, and to address the higher leakage current and oxidation issues in the central portion of the body.
Innovation Solution
Control the molar ratio of Sn/(Ni+Sn) in specific internal electrodes adjacent to cover portions to be between 0.00160 and 0.0230 or less, and in other internal electrodes to be 0.00066 or less, to suppress capacitance decrease and thickness increase, while enhancing connectivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Sn is added to the internal electrode or dielectric layer to improve connectivity and suppress leakage current, then reliability is improved, but rapid shrinkage occurs during sintering causing dielectric layer thickness to increase and capacitance to decrease
Solution Approach 1:
The patent applies local quality by adding Sn specifically to internal electrodes IE1 and IE2 that are in direct contact with the dielectric layer, while keeping other internal electrodes without Sn or with minimal Sn. This localized addition improves connectivity and suppresses leakage current at the critical interface regions without causing uniform shrinkage across the entire component, thereby maintaining dielectric layer thickness precision and capacitance.
2Manufacturing precision
If the dielectric layer is thinned to increase the number of layers for miniaturization and high capacitance, then capacitance is improved, but leakage current increases due to higher electric field
Solution Approach 1:
The patent converts the harmful effect of high electric field in thinned dielectric layers into a benefit by adding Sn to the internal electrodes. The Sn forms a protective region at the interface that suppresses leakage current even when the dielectric layer is extremely thin, enabling miniaturization while maintaining low leakage current through the modified electrode structure.
3Reliability
If Sn is added to form a high Sn amount region at the interface between internal electrode and dielectric layer to suppress leakage current, then reliability is improved, but rapid shrinkage during sintering causes dielectric layer thickness to increase resulting in decrease in capacitance
Solution Approach 1:
The patent implements local quality by restricting Sn addition to only those internal electrodes (IE1 and IE2) that are in direct contact with the dielectric layer, while other internal electrodes spaced apart from the dielectric layer are kept free of Sn or with minimal Sn. This localized approach suppresses leakage current at the critical interfaces without causing uniform shrinkage that would increase overall dielectric layer thickness and reduce capacitance.
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 maintains high capacitance and reliability by controlling Sn distribution, reducing leakage current, and stabilizing the internal electrode surface, thereby improving the overall performance of the multilayer electronic component.
Implementation Method 1
a central portion of a body may have a higher amount of residual carbon and a higher amount of residual sulfur, compared to an edge of the body, and the carbon and the sulfur may be rapidly oxidized at a high temperature, to destabilize a surface of an internal electrode
Implementation Method 2
when Sn is added, rapid shrinkage may occur in length and width directions during a sintering process due to an increase in dielectric sinterability
Data Source
AI summary
A multilayer electronic component includes a body including a capacitance formation portion in which a plurality of dielectric layers and a plurality of internal electrodes are alternately disposed in a first direction, a first cover portion disposed on one surface of the capacitance formation portion in the first direction and including a dielectric layer, and a second cover portion disposed on the other surface of the capacitance formation portion in the first direction and including a dielectric layer; and an external electrode disposed on the body, wherein a molar ratio of Sn/(Ni+Sn) measured in a central portion of an internal electrode disposed closest to the first cover portion or the second cover portion is 0.00160 or more and 0.0230 or less, and a molar ratio of Sn/(Ni+Sn) measured in a central portion of at least one internal electrode, among the plurality of internal electrodes, is 0.00066 or less.