Multilayer Capacitor Electrode Structure to Suppress Ag Ion Migration
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Solution Overview
Problem
Multilayer ceramic capacitors experience deterioration in insulation resistance and short circuit defects due to Ag ion migration in high-temperature and high-humidity environments, particularly when external electrodes containing silver are exposed to moisture.
Innovation Solution
The multilayer electronic component design includes a structure where copper-based base electrode layers are exposed and silver-based electrode layers are limited to specific band portions, minimizing the region of silver exposure to suppress ion migration, and uses conductive adhesives with resins to secure adhesion and reduce thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external electrode including Ag is used, then adhesion strength and reliability in high temperature environments are improved, but Ag ion migration occurs when exposed to moisture causing deterioration in insulation resistance
Solution Approach 1:
The external electrode is divided into two distinct layers: a base electrode layer (Cu or Cu alloy) that provides strong adhesion to the internal electrode, and an electrode layer (Ag or Ag alloy) that offers superior reliability in high temperature environments. This segmentation allows each layer to perform its specific function without the drawbacks of using a single material for both purposes.
Solution Approach 2:
The Cu-based base electrode layer is strategically positioned at the connection portion where adhesion strength is most critical, while the Ag-based electrode layer is positioned at the band portion where high temperature reliability is most important. This local quality assignment optimizes the overall electrode performance by placing each material where it provides the greatest benefit.
2Object-affected harmful factors
If the electrode layer including Ag is disposed to suppress ion migration, then insulation resistance is maintained, but the base electrode layer including Cu becomes exposed to moisture causing oxidation and reduced reliability
Solution Approach 1:
The external electrode uses a composite structure combining Cu-based and Ag-based materials in specific layers. The Cu-based base electrode layer provides oxidation resistance and strong adhesion when exposed to moisture, while the Ag-based electrode layer suppresses ion migration when properly positioned, creating a synergistic effect that overcomes the limitations of individual materials.
3Strength
If Cu-based base electrode layer is exposed to moisture, then adhesion strength is maintained, but oxidation occurs reducing contact resistance and reliability
Solution Approach 1:
The Ag-based electrode layer acts as an intermediary protective layer between the Cu-based base electrode layer and the external environment. It prevents direct contact between moisture and the Cu-based layer, thereby preventing oxidation while still allowing the Cu-based layer to maintain its adhesion strength to the internal electrode.
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 design effectively prevents Ag ion migration, maintaining insulation resistance and preventing short circuits, while enhancing adhesion and reliability in high-temperature and high-humidity conditions, thus improving the component's moisture resistance and manufacturing efficiency.
Implementation Method 1
the first and second base electrode layers include Cu... effectively prevents Ag ion migration, maintaining insulation resistance... enhancing adhesion and reliability in high-temperature and high-humidity conditions
Implementation Method 2
When such an external electrode is used, a multilayer ceramic capacitor may be mounted on a substrate by using conductive glue such as silver epoxy instead of tin soldering... When the external electrode including Ag is exposed to moisture while a voltage is formed, Ag ion migration may occur... effectively suppressing the Ag ion migration
Implementation Method 3
a multilayer ceramic capacitor may be mounted on a substrate by using conductive glue such as silver epoxy instead of tin soldering... uses conductive adhesives with resins to secure adhesion and reduce thermal stress
Implementation Method 4
when such a multilayer ceramic capacitor is mounted on a substrate in a high-temperature and high-vibration environment, a difference in thermal expansion coefficients between tin (Sn) solder, an external electrode, and a substrate may cause a problem of forming solder cracks
Data Source
AI summary
A multilayer electronic component includes: a body including a dielectric layer, first and second internal electrodes, alternately disposed with the dielectric layer disposed therebetween, first and second surfaces opposing each other in a first direction, third and fourth surfaces connected to the first and second surfaces and opposing each other in a second direction, and fifth and sixth surfaces connected to the first to fourth surfaces and opposing each other in a third direction; a first base electrode layer disposed on the third surface and including a first connection portion connected to the first internal electrode; a second base electrode layer disposed on the fourth surface and including a second connection portion connected to the second internal electrode; a first electrode layer disposed on a region including the third surface, the first surface, and the second surface, and formed to expose at least a portion of the first base electrode layer; and a second electrode layer disposed on a region including the fourth surface, the first surface, and the second surface and formed to expose at least a portion of the second base electrode layer, wherein the first and second base electrode layers include Cu, and the first and second electrode layers include Ag.