Coil Component Stress Relaxation Layers
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Solution Overview
Problem
Existing coil components face reliability issues due to electrochemical migration and stress propagation, which lead to cracks in the magnetic body layers and deterioration of insulating properties, caused by gap portions surrounding conductor layers and direct contact between extended conductor portions and magnetic body layers.
Innovation Solution
Incorporating a coil component design with a first and second stress relaxation layer, where the second stress relaxation layer contacts the extended conductor layer and is positioned inside the side gap portion without reaching the outer surface, reducing stress propagation and electrochemical migration, and a first stress relaxation layer contacting the coil conductor layers to alleviate stress application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gap portions surround the extended conductor portions and reach the outer surface, then the conductor layers are isolated from moisture, but plating solution or moisture moves along the gap portions and enters the multilayer body causing electrochemical migration
Solution Approach 1:
The second stress relaxation layer acts as an intermediary barrier between the extended conductor portion and the gap portion reaching the outer surface. This intermediate layer prevents plating solution and moisture from moving along the gap portion and entering the multilayer body, thereby preventing electrochemical migration while maintaining the insulating properties of the original gap structure
2Reliability
If gap portions surround the conductor layers, then electrochemical migration is prevented, but stress of the magnetic body layers propagates to the gap portions and cracks are produced
Solution Approach 1:
The second stress relaxation layer serves as a stress-absorbing intermediary between the extended conductor portion and the magnetic body layers. It prevents stress propagation from the magnetic body layers to the gap portions, thereby preventing crack formation while maintaining the insulating function of the gap structure
3Stress or pressure
If the second stress relaxation layer contacts the coil-conductor-layer side of the extended conductor layer, then stress of the element is reduced, but the structure becomes more complex
Solution Approach 1:
The second stress relaxation layer performs multiple functions simultaneously: it reduces stress on the extended conductor layer, prevents stress propagation to the magnetic body layers, and acts as a barrier against plating solution and moisture. By consolidating these functions into a single layer, the structure achieves stress reduction without proportionally increasing complexity
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 reduces cracks in the coil component, maintains insulation properties, and ensures reliability by minimizing stress propagation and preventing moisture and plating solution entry, thereby enhancing the impedance and inductance characteristics.
Implementation Method 1
a second stress relaxation layer that, while extending along the extended conductor layer, contacts a coil-conductor-layer side of the extended conductor layer
Implementation Method 2
a first stress relaxation layer that contacts the coil conductor layers
Data Source
AI summary
A coil component includes an element and a coil that is provided inside the element and that is spirally wound. The coil includes a plurality of coil conductor layers and an extended conductor layer, which are laminated in a first direction. The extended conductor layer overlaps a side gap portion, which is situated on an outer side of a region of the element that is surrounded by the coil conductor layers, and extends so as to reach an outer surface of the element. The element includes a first stress relaxation layer that contacts the coil conductor layers, and a second stress relaxation layer that, while extending along the extended conductor layer, contacts a coil-conductor-layer side of the extended conductor layer, and is positioned inside the side gap portion without reaching the outer surface of the element.