Dual-Filter Plasma Circuit for Frequency Leakage Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing filter circuits in plasma processing devices experience power leakage and loss due to low impedance at specific frequencies, leading to inefficiencies in plasma processing.
Innovation Solution
A dual-filter circuit configuration is implemented, with a first filter using an air-core coil and series resonant circuit to suppress higher frequencies, and a second filter with a core coil to manage lower frequencies, both connected in series to minimize power leakage to the power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter circuit is used, then the structure is simple, but power leakage and power loss occur at specific frequencies
Solution Approach 1:
The filter circuit is divided into two separate filter circuits with different configurations. The first filter circuit uses an air-core coil and series resonant circuit to suppress higher frequencies (4 MHz or more), while the second filter circuit uses a core coil to suppress lower frequencies (100 Hz or more and less than 4 MHz). This segmentation allows each filter to be optimized for specific frequency ranges, preventing power loss at both high and low frequencies while maintaining overall circuit simplicity.
2Reliability
If a core coil is used for all frequencies, then low frequency suppression is effective, but high frequency power leakage occurs
Solution Approach 1:
Different coil types are used for different frequency ranges based on their specific characteristics. The air-core coil in the first filter circuit is optimized for suppressing high frequencies (4 MHz or more) due to its low inductance and minimal magnetic losses at high frequencies. The core coil in the second filter circuit is optimized for suppressing low frequencies (100 Hz or more and less than 4 MHz) where higher inductance is beneficial. This local quality approach ensures effective suppression at each frequency range without causing power leakage.
3Reliability
If an air-core coil is used for all frequencies, then high frequency suppression is effective, but low frequency power leakage occurs
Solution Approach 1:
The frequency suppression task is segmented between two filter circuits with different coil types. The first filter circuit with the air-core coil handles high frequency suppression (4 MHz or more), while the second filter circuit with the core coil handles low frequency suppression (100 Hz or more and less than 4 MHz). This segmentation allows each filter to operate in its optimal frequency range, preventing power leakage at both high and low frequencies.
4Loss of energy
If filter impedance is low at plasma frequencies, then power loss in plasma is reduced, but power leaks to power supply
Solution Approach 1:
The two filter circuits act as intermediaries between the plasma processing device and the power supply. By placing these filters in the power supply wiring, they selectively block unwanted frequencies from reaching the power supply while allowing plasma frequencies to pass through with minimal loss. The filters serve as a protective barrier that prevents power leakage to the power supply without interfering with plasma processing efficiency.
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 effectively suppresses power leakage and loss, maintaining plasma processing efficiency by ensuring that power frequencies are properly managed and contained within the plasma processing device.
Implementation Method 1
a series resonant circuit which is connected between the wiring and a ground and which has a coil and a capacitor which are connected in series
Implementation Method 2
a first coil which is connected to the wiring in series and which has no core material or has a first core material with a relative permeability of less than 10
Implementation Method 3
a second coil which is connected to the wiring provided between the first coil and the power supply in series and which has a second core material with a relative permeability of 10 or more
Implementation Method 4
a second core material with a relative permeability of 10 or more
Implementation Method 5
suppressing power, which is supplied to plasma, leaking to a power supply
Data Source
AI summary
There is provided a filter circuit provided in a plasma processing device for processing a substrate using plasma generated using power of a first frequency of 4 MHz or more and power of a second frequency of 100 Hz or more and less than 4 MHz. The filter circuit comprises: a first filter provided in a wiring between a conductive member provided in the plasma processing device and a power supply configured to supply power of a third frequency of less than 100 Hz or control power which is direct-current (DC) power, to the conductive member; and a second filter provided in a wiring between the first filter and the power supply.