Capacitor External Electrode Secondary Phase Material
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges with heat and humidity resistance reliability due to poor chemical resistance of glass electrode layers, which can be etched during the plating process, leading to internal defects and reduced reliability.
Innovation Solution
Incorporating a secondary phase material containing sulfur at the boundary between the electrode layer and the plating layer, which forms compounds with materials like tin, copper, nickel, or barium, to enhance chemical resistance and prevent erosion, thereby improving the reliability of the capacitor component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plating layer is formed on the electrode layer to improve mechanical and chemical stability, then mountability and electrical stability are improved, but the glass in the electrode layer is etched by the plating liquid causing internal defects and reduced reliability
Solution Approach 1:
A secondary phase material layer is introduced as an intermediary between the electrode layer and the plating layer. This intermediate layer acts as a protective barrier that prevents the plating liquid from directly contacting and etching the glass in the electrode layer, while still allowing the plating process to proceed effectively on the secondary phase material surface.
Solution Approach 2:
The external electrode structure is designed as a composite multi-layer system consisting of the electrode layer, secondary phase material layer, and plating layer. This composite structure combines the electrical conductivity of the electrode layer with the protective properties of the secondary phase material and the mechanical stability of the plating layer, resolving the contradiction between mountability and chemical resistance.
2Volume of moving object
If the dielectric layer thickness is reduced to achieve miniaturization and high capacitance, then compactness is improved, but heat and humidity resistance reliability is degraded
Solution Approach 1:
The protective function is segmented and applied specifically at the external electrode interface through the secondary phase material layer, allowing the dielectric layer to be thinned for miniaturization while the segmented protective layer at the electrode interface maintains heat and humidity resistance reliability independently of the dielectric thickness.
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 use of sulfur-based secondary phase materials effectively suppresses disconnection of the plating layer and enhances the heat and humidity resistance reliability of the capacitor component, even when the dielectric layer thickness is reduced to 0.4 micrometers or less.
Implementation Method 1
The secondary phase material contains sulfur (S). The sulfur (S) may be contained in the secondary phase material as a compound with at least one selected from the group consisting of tin (Sn), copper (Cu), nickel (Ni), barium (Ba), aluminum (Al), silicon (Si), and oxygen (O).
Data Source
AI summary
A capacitor component includes a body including a dielectric layer and an internal electrode and an external electrode disposed on the body. The external electrode includes an electrode layer connected to the internal electrode, a plating layer disposed on the electrode layer, and a sulfate-based secondary phase material disposed at a boundary between the plating layer and the electrode layer.