Multilayer Ceramic Capacitor Electrodes With Mg Oxide Void Control
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Solution Overview
Problem
Ceramic electronic components, such as multilayer ceramic capacitors, face challenges in maintaining high-temperature load life and moisture resistance due to void formation and crack occurrence when low-melting-point metals like Sn are added to internal electrode layers, and diffusion of external electrode metals like Cu into internal electrode layers.
Innovation Solution
The solution involves adding magnesium (Mg) to the cover layers and side margins with a higher concentration than the dielectric layers, forming oxides containing Ni and Mg at the ends of internal electrode layers to prevent voids and cracks, while using low-melting-point metals like Sn in the internal electrode layers to enhance electrical barrier and high-temperature load life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-melting-point metals like Sn are added to internal electrode layers, then electrical barrier and high-temperature load life are enhanced, but void formation and crack occurrence increase
Solution Approach 1:
The patent introduces an intermediary substance (glass frit or oxide layer) between the low-melting-point metal-containing internal electrode layers and the cover layers. This intermediary prevents direct harmful interaction while allowing the beneficial electrical barrier effect of the low-melting-point metals to be maintained, thereby resolving the contradiction between enhanced reliability and reduced void/crack formation
Solution Approach 2:
The patent changes the chemical composition parameters of the cover layers by adding specific amounts of glass frit or metal oxides (such as SiO2, B2O3, Al2O3). This parameter change modifies the sintering behavior and thermal expansion characteristics, preventing void formation and crack occurrence while preserving the high-temperature load life enhancement from the low-melting-point metals
2Ease of manufacture
If external electrode metals like Cu diffuse into internal electrode layers, then manufacturing process is simplified, but high-temperature load life deteriorates
Solution Approach 1:
The patent uses glass frit or oxide layers as intermediary barrier layers between the external electrodes and internal electrode layers. This intermediary prevents metal diffusion while maintaining electrical connectivity, thus preserving both ease of manufacture and high-temperature load life
Solution Approach 2:
The patent creates a composite structure for the external electrodes consisting of multiple layers (such as Cu base layer, Ni intermediate layer, and protective coating). This composite structure provides both good electrical conductivity for easy manufacturing and diffusion resistance for maintaining reliability at high temperatures
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 configuration improves high-temperature load life and maintains moisture resistance by reducing voids and cracks, ensuring reliable performance under stress conditions.
Implementation Method 1
at least an outermost internal electrode layer of the internal electrode layers has an oxide containing Ni and Mg at both ends in a width direction
Implementation Method 2
each of the internal electrode layers contains a metal component having a melting point of 700° C. or less
Data Source
AI summary
A ceramic electronic component includes a multilayer chip including a multilayer body having cover layers provided on a top and a bottom of a multilayer structure in which dielectric layers and internal electrode layers are alternately stacked, and side margins covering two opposing side surfaces of the multilayer body, wherein the internal electrode layers contain a metal component having a melting point of 700° C. or less, the cover layers has a higher Mg concentration than the dielectric layers, at least an outermost internal electrode layer of the internal electrode layers has oxides containing Ni and Mg at both ends in a width direction, and at least some of the internal electrode layers are in contact with voids at both ends in the width direction in a section where internal electrode layers connected to a first external electrode without internal electrode layers connected to a second external electrode interposed therebetween.