External Electrode Oxide Layer for Stable Solder Mounting
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Solution Overview
Problem
Existing electronic components face issues with oxide layers peeling off from external electrodes under mechanical stress, which can lead to increased mounting area and instability during soldering due to wet solder movement along side surfaces.
Innovation Solution
The electronic component features a base layer with a co-material mixed with metal, a plating layer on certain surfaces, and an oxide layer on others, where the oxide layer includes a surface layer made from the metal's oxide film and a second co-material, providing enhanced adhesion and preventing peeling. This configuration includes a dielectric with a main component like barium titanate and uses specific metals and alloys for the base and plating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the side surface portion of the terminal electrode is covered with an oxide film to prevent wet solder from moving upward, then the mounting area is controlled, but the oxide film may peel along the interface between the terminal electrode and the oxide film when mechanical stress is applied
Solution Approach 1:
The oxide layer is formed as a composite material containing both oxide particles (from the oxide film) and co-material particles (from the base layer material). This composite structure improves adhesion between the oxide layer and the base layer, preventing peeling while maintaining the mounting area control function. The co-material particles act as a bonding bridge between the oxide film and the metal base layer.
Solution Approach 2:
The oxide layer is selectively formed only on specific surfaces of the base layer where adhesion improvement is needed, rather than uniformly across all surfaces. This allows the oxide layer to be applied locally to prevent peeling at critical interfaces while maintaining other functional properties of the electrode surfaces.
2Reliability
If the oxide film is applied to prevent wet solder movement along side surfaces, then soldering stability is improved, but the oxide film may suddenly peel from a large area of the terminal electrode under stress
Solution Approach 1:
By forming the oxide layer as a composite containing oxide particles and co-material particles, the structural integrity is enhanced. The co-material particles distributed within the oxide layer create a reinforced structure that resists sudden large-area peeling while maintaining soldering stability.
Solution Approach 2:
The co-material particles are incorporated into the oxide layer in advance to provide cushioning and stress distribution. This preemptive reinforcement prevents the oxide film from suddenly peeling under mechanical stress during subsequent soldering or handling operations.
3Area of stationary object
If external electrodes are formed on multiple surfaces including side surfaces to reduce mounting area, then compactness is improved, but wet solder may move upward along the side surface and increase mounting area
Solution Approach 1:
The oxide layer, which could potentially peel and cause defects, is transformed into a beneficial barrier by forming it as a composite material with improved adhesion. This converted structure effectively prevents wet solder from moving upward along the side surfaces while maintaining the compact electrode configuration.
Solution Approach 2:
The oxide layer is applied selectively on surfaces where wet solder prevention is needed, creating a local barrier property. This allows the external electrode to maintain its compact multi-surface configuration while preventing harmful solder movement only where necessary.
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 solution effectively prevents the oxide layer from peeling off the external electrodes, reducing the risk of wet solder movement and ensuring stable mounting by enhancing adhesion and heat resistance, thus maintaining a compact mounting area and improving reliability.
Implementation Method 1
an oxide layer which has a surface layer made from an oxide film of the metal of the base layer
Data Source
AI summary
An electronic component includes an element body and at least one external electrode thereon. The element body has a dielectric and inner electrodes. Each external electrode includes a base layer connected to at least one the inner electrode. The base layer is formed on a plurality of surfaces of the element body and contains a metal and a first co-material mixed with the metal. Each external electrode also includes a plating layer formed on at least one face of the base layer. Each external electrode also includes an oxide layer formed on one or more faces of the base layer other than those faces of the base layer on which the plating layer is formed. The oxide layer has a surface layer made from an oxide film of the metal of the base layer and a second co-material.