Nested Air-Core Coil Filter for Low-Frequency RF Blocking
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Solution Overview
Problem
Conventional filters and chokes fail to effectively block low-frequency RF and PV waveform signals, leading to potential damage to circuit components and overheating issues, especially below 5 MHz, due to voltage saturation and size constraints.
Innovation Solution
Incorporation of an air-core coil inductors in analog circuit filters, featuring a folded arrangement of coils to increase inductance and impedance, effectively blocking RF and PV waveform signals, especially at low frequencies, while being cost-effective and compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filters and chokes are used, then device simplicity is maintained, but blocking effectiveness at low frequencies deteriorates
Solution Approach 1:
The air-core coil inductor employs a nested configuration where an inner coil is positioned within an outer coil. This nested structure increases the overall inductance value without proportionally increasing the external dimensions, enabling effective blocking of low-frequency RF and PV waveform signals while maintaining a compact form factor suitable for integration into plasma processing systems.
Solution Approach 2:
The patent transitions from conventional single-coil or planar filter designs to a three-dimensional nested coil structure. By utilizing vertical stacking and radial positioning of coils, the design achieves higher inductance in a compact volume, effectively blocking low-frequency signals without requiring larger device footprints or more complex multi-stage filter topologies.
2Reliability
If inductance is increased to block low-frequency signals, then blocking effectiveness improves, but device size increases
Solution Approach 1:
The air-core coil inductor employs a nested configuration where an inner coil is positioned within an outer coil. This nested structure increases the overall inductance value without proportionally increasing the external dimensions, enabling effective blocking of low-frequency RF and PV waveform signals while maintaining a compact form factor suitable for integration into plasma processing systems.
Solution Approach 2:
The inductor utilizes a composite structural approach combining multiple coil windings with different geometries (inner and outer coils) rather than relying on a single large coil. This composite configuration achieves high inductance through the cumulative effect of multiple smaller coil structures, preventing voltage saturation while maintaining a compact overall size that fits within standard plasma processing chamber constraints.
3Reliability
If conventional chokes are used, then device simplicity is maintained, but voltage saturation occurs at low frequencies
Solution Approach 1:
The inductor utilizes a composite structural approach combining multiple coil windings with different geometries (inner and outer coils) rather than relying on a single large coil. This composite configuration achieves high inductance through the cumulative effect of multiple smaller coil structures, preventing voltage saturation while maintaining a compact overall size that fits within standard plasma processing chamber constraints.
Solution Approach 2:
The inductor is segmented into multiple discrete coil sections (inner coil and outer coil) rather than using a single continuous winding. This segmentation allows the magnetic flux to be distributed across multiple paths, preventing core saturation at low frequencies while maintaining manageable current density in each individual coil section. The segmented structure also facilitates better thermal management and electrical isolation.
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 air-core coil solution enhances filter performance, protects power sources from damage, reduces the risk of accidents, and lowers costs by preventing signal propagation, particularly at low frequencies.
Implementation Method 1
The air-core coil includes a first coil and a second coil disposed within the first coil. The first coil and the second coil together form an inductor configured to at least partially block one or more of a radio frequency (RF) signal or a pulsed voltage (PV) waveform signal from passing through the air-core coil.
Data Source
AI summary
A system includes a processing chamber configured to perform a plasma process with respect to one or more substrates. The system further includes an electrostatic chuck disposed within the processing chamber. The electrostatic chuck includes one or more electrodes. The system further includes an analog filter electrically coupled to at least one electrode of the one or more electrodes. The analog filter includes an air-core coil including a first coil and a second coil disposed within the first coil. The first coil and the second coil together form an inductor.