Coil Component Intermetallic Compound Bonding
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Solution Overview
Problem
The coupling force between the body and external electrode of coil components is problematic, leading to issues with contact resistance, which affects the performance and reliability of the components.
Innovation Solution
A coil component design that includes a body with magnetic powder particles and an insulating resin, a coil portion with lead-out portions exposed on the surface, and an external electrode with an intermetallic compound (IMC) on the lead-out portions, enhancing bonding and reducing resistance through a conductive connection portion in the base resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional external electrode structure is used, then the device complexity is low, but the bonding force between the body and external electrode is insufficient
Solution Approach 1:
The external electrode uses a composite structure consisting of a base resin mixed with conductive particles (silver, copper, or nickel powder) to create a conductive connection portion. This composite material approach provides both mechanical bonding strength and electrical conductivity, resolving the contradiction between bonding force and structural simplicity.
Solution Approach 2:
The patent introduces an intermetallic compound layer (1 μm or more in thickness) as an intermediary between the lead-out portion and the external electrode. This intermediate layer enhances the bonding force and reduces contact resistance without significantly increasing overall device complexity.
2Reliability
If the external electrode is directly formed on the body, then the manufacturing process is simple, but the contact resistance between the external electrode and coil portion is high
Solution Approach 1:
The intermetallic compound layer serves as a mediator between the lead-out portion and the external electrode, reducing contact resistance and improving electrical connection reliability while maintaining a relatively simple manufacturing process.
Solution Approach 2:
The patent specifies that the intermetallic compound layer should have a thickness of 1 μm or more to achieve optimal contact resistance reduction. By controlling this dimensional parameter, the patent optimizes electrical performance without overly complicating the manufacturing process.
3Strength
If a thick intermetallic compound layer is formed, then the bonding force and lead heat resistance improve, but the manufacturing precision requirements increase
Solution Approach 1:
The patent establishes a specific parameter range for the intermetallic compound layer thickness (1 μm or more) to achieve optimal balance between bonding force, lead heat resistance, and manufacturing precision. This quantified parameter guidance helps control manufacturing variability.
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 design increases the bonding force between the body and external electrode, improves component characteristics by reducing contact resistance, and enhances lead heat resistance and solderability, thereby improving the overall performance and reliability of the coil component.
Implementation Method 1
an intermetallic compound (IMC) disposed on the lead-out portion exposed to one surface of the body and having an average thickness of 1 μm or more
Data Source
AI summary
A coil component includes a body including magnetic powder particles and an insulating resin, a coil portion disposed in the body and including a lead-out portion exposed to one surface of the body, and an external electrode disposed on one surface of the body. The external electrode includes an intermetallic compound (IMC) disposed on the lead-out portion exposed to one surface of the body and having an average thickness of 1 μm or more, and a first electrode layer including a base resin, and a conductive connection portion disposed in the base resin and in contact with the intermetallic compound.