Mutually Coupled RF Filters for Plasma Pedestal Channel Matching
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Solution Overview
Problem
Complexity in plasma processing systems leads to increased size and cost due to the need for extensive circuitry to control and monitor parameters, particularly in PECVD reactors, where multiple filters are required for different frequency bands, resulting in labor-intensive tuning and larger filter boxes.
Innovation Solution
The development of a mutually induced filter that filters RF power by twisting and winding wires to form inductors with capacitors, achieving mutual inductance and resonant frequencies, allowing for uniform filtering across multiple channels with fewer filters, reducing size, cost, and assembly time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate filters are used for different frequency bands in plasma processing systems, then filtering performance for each frequency band is improved, but the number of filters increases from 12 to 96, resulting in increased system size, complexity, and assembly time
Solution Approach 1:
The patent combines multiple separate filters into a single mutually induced filter assembly where multiple inductors share common magnetic paths and cores. This merging approach maintains the filtering performance for different frequency bands while reducing the total number of discrete filter components from 96 to 12, thereby reducing system complexity and assembly requirements
Solution Approach 2:
The mutually induced filter assembly is designed to perform multiple filtering functions simultaneously across different frequency bands using shared magnetic components. Each inductor can be tuned to different resonant frequencies while sharing common magnetic paths, allowing a single filter assembly to replace multiple separate filters and provide universal filtering coverage
2Reliability
If multiple separate filters are used for different frequency bands, then filtering performance is improved, but the physical size of filter boxes increases due to the larger number of components
Solution Approach 1:
By merging multiple filters into a single mutually induced filter assembly with shared magnetic cores and paths, the physical footprint is dramatically reduced. The compact integration of multiple inductors around common magnetic structures eliminates the need for multiple separate filter boxes, thereby reducing the overall area occupied by filtering components
3Reliability
If multiple separate filters are used for different frequency bands, then filtering performance is improved, but assembly time and labor requirements increase due to the larger number of components
Solution Approach 1:
The mutually induced filter assembly integrates multiple inductors and magnetic paths into a single assembly unit that can be installed as one component rather than assembling 96 separate filters. This merging reduces assembly steps, fastener installations, and alignment operations, thereby significantly reducing assembly time and labor requirements while maintaining filtering performance
4Adaptability or versatility
If extensive circuitry is added to plasma processing systems to control and monitor parameters, then system control capability is improved, but the size and cost of the reactor system increase
Solution Approach 1:
The mutually induced filter assembly consolidates multiple filtering functions into a single integrated component, reducing the overall system complexity and size. By combining multiple inductors and magnetic paths into one assembly, the physical footprint and component count are reduced while maintaining the adaptability and control capability needed for monitoring and controlling plasma processing parameters
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 mutually induced filter achieves improved common mode rejection and channel-to-channel matching, reducing the number of filters needed from 96 to 12, resulting in smaller, more efficient, and easier-to-assemble systems with uniform resonant frequencies across stations.
Implementation Method 1
A resonant frequency of a combination of the capacitor and the one of the inductors is transferred from the one of the inductors to remaining of the inductors of the mutually induced filter so that the mutually induced filter has the resonant frequency
Implementation Method 2
The mutually induced filter is fabricated by twisting one or more wires to form a combination of wires and then winding the combination into a plurality of turns to form multiple inductors
Data Source
AI summary
A mutually induced filter for filtering radio frequency (RF) power from signals supplied to a load is described. The mutually induced filter includes a first portion connected to a first load element of the load for filtering RF power from one of the signals supplied to the first load element. The load is associated with a pedestal of a plasma chamber. The mutually induced filter further includes a second portion connected to a second load element of the load for filtering RF power from another one of the signals supplied to the second load element. The first and second portions are twisted with each other to be mutually coupled with each other to further facilitate a coupling of a resonant frequency associated with the first portion to the second portion.