Multilayer Capacitor Oxide Layer Moisture Resistance
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in moisture resistance reliability due to weak coherence between glass and electrode layers, which can lead to moisture penetration.
Innovation Solution
A multilayer capacitor design incorporating an oxide layer with a metal oxide and glass between the first and second electrode layers, where the metal oxide is formed by oxidizing the first electrode layer, and the second electrode layer is a sintered conductive metal and glass, improving interfacial coherence and moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass layer is formed between electrode layers to improve moisture resistance, then moisture resistance reliability is improved, but weak coherence between glass layer and electrode layer creates moisture penetration routes
Solution Approach 1:
The patent applies composite materials by creating a multi-layer external electrode structure consisting of a first electrode layer (Ni), an oxide layer (NiO), and a second electrode layer (Cu). This composite structure replaces the simple glass layer with a layered composite that provides both moisture resistance and strong interfacial coherence through oxidation bonding between layers.
Solution Approach 2:
The patent applies parameter changes by controlling the thickness of the oxide layer (0.2 to 8 μm) and the metal content (10 to 80 wt%) to optimize both moisture resistance and interfacial coherence. The oxidation process transforms the first electrode layer into an oxide layer with specific physical and chemical properties that enhance bonding while maintaining moisture barrier functionality.
2Reliability
If the oxide layer thickness is increased to improve moisture resistance, then moisture penetration is prevented, but electrical connectivity may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the oxide layer thickness within a specific range (0.2 to 8 μm) and metal content (10 to 80 wt%). This controlled parameter range ensures sufficient thickness for moisture resistance while maintaining adequate electrical conductivity through the external electrode structure.
Solution Approach 2:
The patent uses composite materials by combining the oxide layer with conductive metal particles in the second electrode layer. This composite structure provides both the moisture barrier function of the oxide and the electrical conductivity of the metal, resolving the contradiction between moisture resistance and electrical connectivity.
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
The proposed design enhances moisture resistance reliability by preventing moisture penetration routes and maintaining electrical connectivity, with optimal metal content and thickness of the oxide layer between 10 wt% and 80 wt% and 0.2 to 8 μm, respectively.
Implementation Method 1
the metal oxide is formed by oxidizing the first electrode layer
Implementation Method 2
the second electrode layer is a sintered electrode including a conductive metal and glass
Data Source
AI summary
A multilayer capacitor includes a body including an internal electrode alternately disposed with a dielectric layer, and an external electrode disposed on the body. The external electrode includes a first electrode layer contacting the internal electrode, an oxide layer disposed on the first electrode layer and including a metal oxide and glass, and a second electrode layer disposed on the oxide layer.