Coil Component Insulation Structure for Selective Terminal Plating
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Solution Overview
Problem
In coil components with a magnetic element body containing conductive magnetic powder, excessive etching during electrolytic plating can expose the coil conductor pattern and lead to unwanted plating adhesion, compromising the component's integrity and mounting reliability.
Innovation Solution
A protective insulating layer covers the magnetic element body, including the external terminal, to prevent plating adhesion and exposure of the coil conductor pattern, while the external terminal is formed using conductive paste to avoid electrolytic plating-related issues, and the entire surface is covered to enhance adhesion and prevent solder spreading during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface of the magnetic element body is subjected to soft etching before electrolytic plating, then plating adhesion is improved, but the coil conductor pattern may be exposed
Solution Approach 1:
A protective insulating layer is formed on the magnetic element body before electrolytic plating to prevent the plating solution from reaching and etching the coil conductor pattern. This preliminary protective action allows the plating process to proceed without risking pattern exposure while still achieving adequate adhesion on the external terminal surfaces.
Solution Approach 2:
The protective insulating layer acts as an intermediary barrier between the electrolytic plating solution and the magnetic element body surface. It selectively protects the coil conductor pattern while allowing plating to occur on intended areas, thus mediating between the need for plating adhesion and the need to prevent pattern exposure.
2Reliability
If electrolytic plating is applied to form external terminals, then terminal conductivity is improved, but plating may adhere to unnecessary portions of the magnetic element body
Solution Approach 1:
The harmful effect of unwanted plating adhesion is extracted and isolated by introducing a protective insulating layer that prevents plating solution contact with unnecessary portions of the magnetic element body. This allows electrolytic plating to be applied for terminal conductivity improvement without the side effect of unwanted plating elsewhere.
Solution Approach 2:
The protective insulating layer serves as an intermediary that controls where plating occurs. It blocks the plating solution from reaching unnecessary portions of the magnetic element body while allowing plating to proceed on the external terminal areas, thus mediating between conductivity needs and unwanted plating prevention.
3Strength
If the magnetic element body surface is etched to improve plating adhesion, then plating bonding strength is enhanced, but the coil conductor pattern becomes exposed
Solution Approach 1:
The protective insulating layer is applied in advance before the plating process to prevent etching of the coil conductor pattern. This preliminary protection enables adequate plating bonding strength to be achieved on external terminals without compromising the integrity of the embedded coil conductor pattern.
Solution Approach 2:
The protective insulating layer acts as an intermediary barrier that prevents the plating solution from etching the coil conductor pattern while still allowing controlled plating on external terminals. This mediates between achieving plating bonding strength and maintaining pattern integrity.
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 solution effectively prevents plating adhesion to unnecessary portions and exposure of the coil conductor pattern, ensuring reliable mounting and enhanced adhesion between the magnetic element body and the protective insulating layer, thereby improving the component's structural integrity and mounting strength.
Implementation Method 1
it is possible to prevent adhesion of plating to an unnecessary portion and exposure of the coil conductor pattern even when the surface of the external terminal is subjected to electrolytic plating
Implementation Method 2
the external terminal may be made of conductive paste
Data Source
AI summary
A coil component includes: a magnetic element body made of resin containing conductive magnetic powder; a coil part 20 obtained by alternately stacking a plurality of conductor layers and a plurality of interlayer insulating layers, the plurality of conductor layers respectively including coil conductor patterns embedded in the magnetic element body and electrode patterns exposed from the magnetic element body; external terminals provided respectively on the electrode patterns and electrode patterns; and a protective insulating layer covering the magnetic element body in such a manner as to expose the external terminals therethrough. The magnetic element body is thus covered with the protective insulating layer, so that it is possible to prevent adhesion of plating to an unnecessary portion and exposure of the coil conductor patterns even when the surfaces of the external terminals are subjected to electrolytic plating.