MLCC External Electrode Alloy Structure Against Hydrogen Penetration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reliability of multilayered ceramic capacitors (MLCC) deteriorates due to hydrogen penetration from glass component erosion during external electrode plating, which compromises adhesion force and initial reliability.
Innovation Solution
The external electrode is formed with a first layer comprising a eutectic alloy of copper and silver, lacking glass components, and includes an alloy portion and diffusion portion alternately disposed along the dielectric and internal electrodes, preventing hydrogen penetration and enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass component is used to secure adhesion force between external electrode and capacitor body, then adhesion force is improved, but glass component is eroded by plating solution during external electrode formation
Solution Approach 1:
The patent removes the glass component from the external electrode composition entirely. The external electrode is formed using only metal powders (such as copper, silver, nickel) and organic vehicles without any glass frit, thereby eliminating the source of erosion by plating solution while maintaining adhesion through metal-to-ceramic bonding mechanisms.
Solution Approach 2:
The patent changes the chemical composition parameters of the external electrode by substituting glass-containing paste with glass-free metal powder paste. This parameter change eliminates the harmful interaction with plating solution while preserving the essential adhesion function through alternative bonding mechanisms between metal and ceramic substrates.
2Strength
If glass component is used to secure adhesion force between external electrode and capacitor body, then adhesion force is improved, but hydrogen generated during plating penetrates into capacitor body
Solution Approach 1:
By removing the glass component from the external electrode formulation, the patent eliminates the pathway through which hydrogen generated during plating could penetrate into the capacitor body. The glass-free composition prevents hydrogen generation and subsequent penetration, thereby improving reliability.
Solution Approach 2:
The patent converts the potential harm of hydrogen penetration into a benefit by eliminating the glass component that would generate hydrogen during plating. The absence of glass prevents the harmful reaction entirely, turning a potential failure mode into a reliability advantage.
3Strength
If glass component is used to secure adhesion force between external electrode and capacitor body, then adhesion force is improved, but glass component erosion occurs during external electrode formation
Solution Approach 1:
The patent extracts and removes the glass component from the external electrode paste formulation. By forming the external electrode using only metal powders and organic vehicles without glass frit, the patent eliminates glass component erosion during the plating process while maintaining adhesion through metal-to-ceramic bonding.
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 maintains adhesion force and prevents glass component erosion, thereby improving the initial reliability of the capacitor by reducing hydrogen penetration.
Implementation Method 1
a first layer disposed outside the capacitor body and including a first conductive metal, a second conductive metal, and an alloy thereof, and the first layer includes an inner layer including an alloy portion at a portion meeting the dielectric layer and a diffusion portion at a portion meeting the internal electrode
Implementation Method 2
The alloy of the first conductive metal and the second conductive metal may be a eutectic alloy
Data Source
AI summary
A multilayered capacitor includes a capacitor body including a dielectric layer and an internal electrode, and an external electrode outside the capacitor body, in which the external electrode includes a first layer disposed outside the capacitor body and including a first conductive metal, a second conductive metal, and an alloy thereof, and the first layer includes an inner layer including an alloy portion disposed at a portion meeting the dielectric layer and including the alloy, and a diffusion portion disposed at a portion meeting the internal electrode and including the first conductive metal, a third conductive metal included in the internal electrode, an alloy thereof, or a combination thereof.