Multi-Antenna Plasma Reactance Control for Uniform Current Distribution
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Solution Overview
Problem
Existing plasma treatment devices with multiple antennas struggle to maintain uniform plasma density and current distribution when dealing with larger substrates, as the impedance adjustments for one antenna affect others, leading to non-uniform plasma generation.
Innovation Solution
A plasma control system with a high-frequency power supply, multiple antennas, reactance variable elements, a current detection mechanism, and a uniformity calculation unit that adjusts reactances to achieve uniform current flow and plasma density across all antennas, using a configuration of antennas connected in series and parallel with reactance variable elements on both feeding and ground sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a long antenna is used to cope with large substrates, then the substrate coverage area is improved, but the current distribution uniformity along the antenna deteriorates
Solution Approach 1:
The patent divides the long antenna into multiple segments along its length, with each segment having an independently controllable reactance variable element. This segmentation allows independent adjustment of current distribution in different regions of the antenna, enabling uniform current distribution even for long antennas covering large substrates.
Solution Approach 2:
The patent introduces reactance variable elements that can dynamically adjust their reactance values based on detected current distribution. This dynamic adjustment capability allows the system to compensate for non-uniform current distribution in real-time, maintaining uniform plasma generation across the entire substrate area.
2Area of stationary object
If multiple antennas are used to cover large substrates, then the substrate coverage is improved, but the plasma density uniformity deteriorates
Solution Approach 1:
The patent employs a feedback control system where current distribution is detected along the antennas, and the detected information is used to adjust the reactance values of reactance variable elements. This feedback mechanism ensures that plasma density uniformity is maintained across multiple antennas by continuously monitoring and adjusting current distribution based on actual measurements.
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 ensures uniform plasma generation along the antennas, enabling effective plasma control for larger substrates by making the current flow as uniform as possible and allowing for precise plasma density control.
Implementation Method 1
inductively coupled plasma generated by allowing a high-frequency current to flow through an antenna
Implementation Method 2
a plurality of reactance variable elements connected to a feeding side and a ground side of the plurality of antennas
Implementation Method 3
a current detection mechanism that detects a current flowing through the feeding side and the ground side of the plurality of antennas
Data Source
AI summary
The present invention comprises: a high-frequency power supply; an antenna group having a plurality of antennas connected to the high-frequency power supply; a plurality of reactance variable elements connected to the feeding sides and the grounding sides of the plurality of antennas; a current detection mechanism which detects the current flowing through the feeding sides and the ground sides of the plurality of antennas; a uniformity calculation unit which calculates the uniformity index value of the current flowing through the plurality of antennas, on the basis of the current value detected by the current detection mechanism; and a reactance changing unit which sequentially changes the reactance of the plurality of reactance variable elements such that the uniformity index value calculated by the uniformity calculation unit approaches a predetermined set value.