Ceramic Capacitor Electrode Oxide Formation for Crack Prevention
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Solution Overview
Problem
The challenge is to prevent cracks and improve contact between internal and external electrodes in ceramic electronic components, particularly in multilayer ceramic capacitors with thin internal electrode layers and reduced baking temperatures, which can lead to insufficient reaction and degraded contact.
Innovation Solution
The solution involves forming oxides containing Zn and Ni around the internal electrode layers near the connection points with external electrodes by using a conductive paste with a glass component containing 20-30 weight % ZnO, applied during the baking process, to enhance adhesion and prevent moisture penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of the internal electrode layer is reduced to increase the number of stacked layers, then the capacitance and size are improved, but the contact between the internal electrode layer and the external electrode is degraded
Solution Approach 1:
The patent changes the chemical composition parameters of the external electrode, specifically incorporating glass components with 20-30 weight % ZnO. This compositional parameter change enables effective contact formation with thinner internal electrode layers (0.5 μm or less) by enhancing the chemical reaction and adhesion at the interface, thus maintaining contact quality while achieving higher capacitance density.
Solution Approach 2:
The glass component containing ZnO acts as an intermediary substance between the internal electrode layer and the external electrode. It facilitates the chemical reaction and bonding process, enabling reliable contact formation even when the internal electrode layer thickness is reduced to increase the number of stacked layers for higher capacitance.
2Productivity
If the number of internal electrode layers and dielectric layers is increased by thinning the cover layer, then the capacitance and size are improved, but cracks occur in the area where the cover layer, side margin, and end margin overlap
Solution Approach 1:
The patent applies a localized protective composition containing high ZnO glass components specifically at the connection parts where internal electrodes meet external electrodes. This local enhancement of chemical stability and adhesion prevents crack propagation from the electrode interfaces into the cover layer, allowing thinner cover layers to be used without compromising structural integrity.
Solution Approach 2:
The external electrode composition with ZnO-containing glass components provides beforehand cushioning by creating a flexible, adherent interface layer that absorbs thermal stress and mechanical stress during the stacking process. This prevents cracks from forming in the overlapping regions of the cover layer, side margin, and end margin when multiple thin layers are stacked.
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 effectively inhibits crack formation and improves the contact between internal and external electrodes, enhancing the moisture-resistant reliability of the ceramic capacitors even at lower baking temperatures.
Implementation Method 1
baking the second conductive paste to form oxides including Zn and Ni around each of the internal electrode layers
Implementation Method 2
the length of the region where the metal component of the external electrode is diffused in the internal electrode layer (the diffusion length)
Data Source
AI summary
A ceramic electronic component includes a multilayer chip having a substantially rectangular parallelepiped shape and including dielectric layers and internal electrode layers that are alternately stacked, the internal electrode layers being alternately exposed to two edge faces of the multilayer chip facing each other, and a pair of external electrodes respectively formed on the two edge faces so as to be connected to the internal electrode layers exposed on the respective edge faces, each external electrode extending to at least one side face of the multilayer chip, wherein in the multilayer chip, oxides including Zn and Ni are present around the internal electrode layer in a vicinity of a connection part connecting the internal electrode layer to the external electrode.