BEOL Inductor with Composite Magnetic Core
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Solution Overview
Problem
Conventional inductor formation in semiconductor fabrication faces challenges with air-core inductors having low energy storage capacity and electroplated NiFe inductors suffering from eddy current losses, which limit their performance in radiofrequency and DC-DC power converter applications.
Innovation Solution
The use of a conductive coil with a central core area filled with a composite material comprising magnetic particles dispersed in a polymer matrix, formed using a screen-printing process to reduce eddy current losses and enhance energy storage, where the particles are coated with polyelectrolytes to achieve high density packing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If air-core inductors are used, then the inductor structure is simple and easy to manufacture, but the energy storage capacity is low
Solution Approach 1:
The patent uses a composite core material consisting of magnetic particles (such as ferrite or iron oxide) dispersed in a polymer matrix. This composite structure combines the magnetic properties needed for energy storage with the electrical insulation properties that prevent eddy currents, thereby increasing energy storage capacity while maintaining manufacturability
Solution Approach 2:
The patent applies magnetic particles specifically in the central core region where the magnetic flux density is highest, while maintaining air or polymer in the outer regions. This localized application of magnetic material optimizes energy storage capacity by concentrating the magnetic enhancement where it is most needed, without requiring the entire inductor structure to be complex
2Quantity of substance
If electroplated NiFe inductors are used, then the energy storage capacity increases, but eddy current losses occur
Solution Approach 1:
The patent employs a porous or particulate structure where magnetic particles are dispersed in a polymer matrix rather than using solid continuous metal. This discontinuous structure interrupts the path for eddy currents while maintaining sufficient magnetic permeability for energy storage, effectively reducing eddy current losses
Solution Approach 2:
The magnetic particles are strategically distributed in regions of high magnetic flux density within the core, providing localized magnetic enhancement where needed while maintaining electrical insulation throughout the structure to prevent eddy current formation
3Loss of energy
If laminated structures are used to reduce eddy current, then eddy current loss decreases, but current/charge confinement is limited by patterning
Solution Approach 1:
The patent uses a composite material approach where magnetic particles are mixed with polymer to create a homogeneous core material that inherently prevents eddy currents through its discontinuous structure, eliminating the need for complex laminated patterning while maintaining simplicity in fabrication
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 approach significantly increases energy storage capacity while minimizing power loss due to eddy currents, improving the performance of inductors in high-frequency applications.
Implementation Method 1
electroplated NiFe inductors suffer from loss due to eddy currents
Implementation Method 2
The particles include magnetic properties
Implementation Method 3
increase energy storage
Data Source
AI summary
A method for forming an inductor device. The method comprises forming a trench within a central core region of a conductive coil formed within a dielectric material. The method further comprises forming a composite region within the trench. The composite region including a polymer matrix having a plurality of particles with magnetic properties dispersed therein with the central core region to reduce eddy current loss and increase energy storage.