Thin-Film Coil Component for Miniaturized Common Mode Filter

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Solution Overview

Problem

Conventional common mode filters are difficult to miniaturize and manufacture at a low cost due to the use of thick ferrite substrates and complex electrode structures, which result in high manufacturing costs and precision issues with terminal electrodes.

Innovation Solution

A coil component with a thin-film coil layer on a substrate, featuring bump electrodes and lead conductors formed integrally with the coil layer, eliminating the need for additional insulating layers and allowing for precise external terminal electrodes, thereby reducing material costs and increasing common mode impedance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thick ferrite substrates are used to provide mechanical strength and magnetic properties, then the structural integrity and magnetic performance are improved, but the component size increases and manufacturing cost rises

Engineering Contradiction:

Improvemechanical strengthVSAvoidcomponent size

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The patent applies thin-film technology to create coil conductors with thickness of 1 µm or less on a substrate. This thin-film approach allows the component to achieve the required magnetic properties and mechanical strength without using thick ferrite substrates, thereby reducing the overall component size while maintaining structural integrity

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses composite material structures combining thin-film coil conductors with substrate materials to achieve both mechanical strength and magnetic properties. The composite structure allows optimization of each layer's thickness and material properties, reducing the need for thick substrates while maintaining overall performance

Inventive Principle:

Principle #40Composite materials

2Reliability

If complex electrode structures with multiple insulating layers are used to ensure electrical isolation, then the electrical insulation performance is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improveelectrical insulation performanceVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates unnecessary insulating layers from the conventional structure. By carefully analyzing the electrical isolation requirements, the design removes redundant insulation layers while maintaining adequate electrical insulation performance, thereby simplifying the overall structure and reducing manufacturing complexity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of adding more insulating layers to ensure electrical isolation, the patent inverts the approach by using precise conductor routing and strategic placement of minimal insulation where absolutely necessary. This inversion leads to a simpler structure that achieves the same electrical isolation performance

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If conventional terminal electrode formation methods are used to ensure electrical connection, then the electrical connectivity is achieved, but the manufacturing precision and cost-effectiveness deteriorate

Engineering Contradiction:

Improveelectrical connectivityVSAvoidelectrode precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the formation parameters of terminal electrodes by integrating them with the thin-film coil conductor fabrication process. By using the same thin-film deposition and patterning techniques for both coil conductors and terminal electrodes, the manufacturing precision is improved while maintaining reliable electrical connectivity, and the process is more cost-effective

Inventive Principle:

Principle #35Parameter changes

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 enables the production of miniaturized, cost-effective common mode filters with improved precision and reduced DC resistance, while maintaining desired filter performance.

Implementation Method 1

a first spiral conductor (16), which is a plane coil pattern, and a second spiral conductor (17) magnetically coupled to the first spiral conductor (16)

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

first and second bump electrodes (13a, 13b) provided on a surface of the thin-film coil layer (12)

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS8564393B2Coil component and method of manufacturing the same

Publication Date: 2013.10.22 TDK CORP

AI summary

A coil component 100 is provided with a substrate 11, a thin-film coil layer 12 provided on the substrate 11, first and second bump electrodes 13a, 13b provided on a surface of the thin-film coil layer 12, a first lead conductor 20 provided on the surface of the thin-film coil layer 12 together with the first and second bump electrodes 13a, 13b and formed integrally with the first bump electrode 13a, and an insulator layer 14 provided between the first bump electrode 13a and the second bump electrode 13b. The thin-film coil layer 12 contains a first spiral conductor 16 which is a plane coil pattern. The first bump electrode 13a is connected to an internal peripheral end of the first spiral conductor 16 via the first lead conductor 20. The second bump electrode 13b is connected to an external peripheral end of the first spiral conductor 16.