3D Helix Inductor Structure for High Q Value
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Solution Overview
Problem
Conventional inductor structures in integrated circuits face limitations due to metal thickness constraints and silicon substrate interference, leading to lower quality factors (Q values) and increased conductor loss, as increasing metal thickness beyond a certain point offers diminishing returns in improving Q values.
Innovation Solution
The inductor structure features a three-dimensional helix configuration with winding turns of varying widths, where the wider turns are positioned closer to the substrate to reduce resistance and parasitic capacitance, and additional winding turns or gain wires are integrated in series or parallel to increase the cross-sectional area, thereby enhancing the Q value and reducing conductor loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the metal winding is increased to increase the section area and reduce the resistance, then the Q value is improved, but the device complexity and manufacturing constraints are worsened due to metal thickness limitations in integrated circuits
Solution Approach 1:
The patent transitions from a conventional planar inductor structure to a three-dimensional helix structure. By stacking multiple winding turns vertically at different heights above the substrate, the design exploits the third dimension (vertical stacking) to increase the effective conductor cross-sectional area without increasing the planar footprint. This dimensional transition allows achieving lower resistance and higher Q values while respecting integrated circuit manufacturing constraints on metal thickness.
Solution Approach 2:
The patent implements a nested configuration where multiple winding turns are stacked vertically, with each turn positioned at a different height above the substrate. The turns are arranged concentrically and electrically connected in series, creating a nested three-dimensional structure. This nesting approach maximizes the use of vertical space to increase the effective conductor area while maintaining a compact footprint suitable for integrated circuits.
2Loss of energy
If the metal thickness is increased beyond a certain level to further reduce conductor loss, then the Q value improvement becomes less prominent, but the manufacturing difficulty and process complexity increase
Solution Approach 1:
Instead of continuing to increase metal thickness in the vertical direction (which faces manufacturing limits), the patent distributes the conductor volume across multiple horizontal layers at different heights. This approach increases the effective cross-sectional area perpendicular to the current flow without requiring excessively thick single-layer metal, thereby reducing conductor loss while remaining within standard IC fabrication capabilities.
Solution Approach 2:
The patent divides the continuous conductor into multiple discrete winding turns positioned at different heights. Each turn is a separate conductive element that can be independently formed using standard metal deposition processes. These segmented turns are then electrically connected in series to form the complete inductor, allowing the total conductor volume to be distributed across multiple manufacturable layers.
3Reliability
If conventional planar inductor structures are used, then the manufacturing process is simple, but the Q value is limited due to substrate interference and metal thickness constraints
Solution Approach 1:
The patent employs vertical stacking of winding turns at multiple heights above the substrate, creating a three-dimensional helix structure. This dimensional transition increases the distance between the conductor and the lossy silicon substrate, reducing substrate interference and parasitic effects. Simultaneously, the vertical arrangement increases the effective conductor cross-sectional area, lowering resistance and improving Q value despite the increased structural 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 configuration significantly improves the Q value and quality of the inductor across a wide frequency range, including radio frequencies, by minimizing conductor loss and parasitic capacitance while maintaining a low electric field near the substrate, thus enhancing the overall performance of the inductor.
Implementation Method 1
an inductor functions as a device for saving and releasing energy through the inter-conversion between electrical and magnetic fields
Implementation Method 2
the wider turns are positioned closer to the substrate to reduce resistance and parasitic capacitance
Data Source
AI summary
An inductor structure including a first winding turn and a second winding turn is provided. The first winding turn is disposed above a substrate. The second winding turn is disposed between the first winding turn and the substrate. One end of the second winding turn is grounded, and the other end of the second winding turn and the first winding turn are electrically connected in series. The first winding turn and the second winding turn form a three-dimensional helix structure above the substrate. The width of the second winding turn is greater than that of the first winding turn, and furthermore, the first winding turn is projected onto the second winding turn.