Intertwisted Spiral Inductor for Eddy Current Reduction
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Solution Overview
Problem
Conventional inductor structures in integrated circuits face challenges due to the limitations of thickness and interference from silicon substrates, leading to poor inductor quality, particularly due to eddy currents that affect current uniformity and reduce the quality factor (Q value).
Innovation Solution
The inductor structure comprises intertwisted spiral wires with a symmetry plane, where the outermost coil turn is grounded, reducing eddy current impact and incorporating a gain wire to increase the cross-sectional area, thereby improving inductor quality and reducing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a thick metal is disposed on the top layer of the inductor to reduce conductor loss, then the Q value is improved, but the inductor structure is still influenced by eddy current which reduces inductor quality
Solution Approach 1:
The patent divides the inductor structure into two separate spiral wires (first spiral wire and second spiral wire) that are intertwined. Each spiral wire carries current in opposite directions, which segments the current path and reduces eddy current effects. This segmentation allows the inductor to maintain thick metal for low conductor loss while mitigating eddy current interference through the alternating current directions in the intertwined structure.
2Ease of manufacture
If conventional inductor structure is used with silicon substrate, then manufacturing is simplified, but the interference of silicon substrate to the inductor leads to poor inductor quality
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the silicon substrate and the inductor structure. This dielectric layer acts as a mediator that electrically isolates the inductor from the silicon substrate, reducing substrate interference and improving inductor quality. The intertwined spiral wire structure further serves as an intermediary mechanism that maintains manufacturing simplicity while enhancing performance through its specific electromagnetic field distribution pattern.
3Use of energy by moving object
If the inner coil turn has maximum magnetic flux, then the inductor stores more energy, but the inner portion is most affected by eddy current which makes current non-uniform
Solution Approach 1:
The patent employs asymmetric current distribution in the intertwined spiral wires where the first and second spiral wires carry currents in opposite directions. This asymmetric arrangement creates opposing magnetic fields that cancel eddy current effects in the inner coil turns, allowing the inner portions to maintain both high magnetic flux for energy storage and uniform current distribution. The asymmetric current paths prevent the buildup of non-uniform eddy currents while preserving the energy storage capability.
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 alleviates eddy current effects, enhances inductor quality by optimizing current distribution, and minimizes power loss in direct current applications by utilizing the outermost coil turn for power supply connection.
Implementation Method 1
inductors store and release energy through the mutual transformation between electricity and magnetism
Implementation Method 2
the inductor structure may still be influenced by an eddy current
Data Source
AI summary
An inductor structure disposed over a substrate and comprising a first spiral wire and a second spiral wire is provided. The first spiral wire has a first end and a second end. The first end rotates in a spiral way outward from an inner portion of the first spiral wire. The second spiral wire and the first spiral wire are intertwisted with each other and symmetrically disposed about a symmetry plane. The second spiral wire has a third end and a fourth end. The third end rotates in a spiral way outward from an inner portion of the second spiral wire and is connected to the first end of the first spiral wire, so as to form a coil layer having a plurality of coil turns.