Dual-Frequency Antenna Plasma Generation Efficiency
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Solution Overview
Problem
Conventional substrate processing apparatuses face reduced plasma density and generation efficiency due to asymmetric plasma generation, where plasma is generated on both sides of the substrate while processing is only performed on one side, leading to inefficient plasma utilization.
Innovation Solution
A substrate processing apparatus employing a combination of low frequency and high frequency antenna units, where the low frequency antenna unit includes a ferrite core with a plurality of poles and an antenna coil, and the high frequency antenna unit consists of multiple coil groups connected in series or a single spiral coil, to generate plasma efficiently across the reaction space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma is generated on both sides of the substrate in conventional apparatuses, then the substrate can be processed, but plasma density and generation efficiency are reduced due to asymmetric plasma utilization
Solution Approach 1:
The patent segments the plasma generation system into distinct low frequency and high frequency antenna units with different functional roles. The low frequency unit handles stable ignition and maintenance while the high frequency unit provides high-density plasma generation, allowing each segment to operate optimally without the conflicts present in conventional single-system designs.
Solution Approach 2:
The patent changes the frequency parameter by introducing dual-frequency operation. Low frequency (e.g., 13.56 MHz) is used for stable plasma ignition and maintenance, while high frequency (e.g., 27.12 MHz) is used for high-density plasma generation. This parameter differentiation resolves the contradiction between stability and efficiency by assigning different frequency bands to different functional requirements.
2Reliability
If conventional single-frequency antenna systems are used, then the system is simpler, but plasma ignition stability and generation efficiency cannot be simultaneously optimized
Solution Approach 1:
The antenna system is segmented into functionally distinct low frequency and high frequency units. Each unit is optimized for its specific frequency range and function, with the low frequency unit providing stable ignition and the high frequency unit providing efficient plasma generation. This segmentation allows both reliability and controlled complexity to be achieved.
Solution Approach 2:
The patent creates a multi-functional antenna system where low frequency antennas provide both ignition and maintenance functions, while high frequency antennas provide high-density plasma generation. This universal design allows a single integrated system to perform multiple functions that would otherwise require separate systems, managing complexity while improving performance.
3Productivity
If ferrite core is added to improve inductive coupling, then plasma generation efficiency increases, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The ferrite core is applied locally at specific positions where inductive coupling is most critical, rather than throughout the entire antenna structure. This localized application maximizes the benefit to inductive coupling efficiency while minimizing the added complexity and manufacturing difficulty associated with ferrite core integration.
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 enhances plasma generation efficiency by stabilizing plasma ignition and improving uniformity, allowing for high-density plasma generation suitable for large substrates, even under varying pressure conditions, by leveraging the high magnetic permeability of the ferrite core for improved inductive coupling and eliminating transmission line effects.
Implementation Method 1
leveraging the high magnetic permeability of the ferrite core for improved inductive coupling
Implementation Method 2
a coil 142 turned therearound such that the coil 142 around one ferrite core 141 is turned in an opposite direction to a turning direction of the coil 142 of an adjacent toroidal ferrite core 141 in order to cause adjacent toroidal ferrite cores 141 to generate induced electromotive forces having opposite phases
Implementation Method 3
The induced electromotive forces generated by the adjacent toroidal ferrite cores 141 have a phase difference of 180 degrees with respect to each other, and a current path induced by the plasma constitutes a closed path through adjacent holes 152
Data Source
AI summary
A substrate processing apparatus. The substrate processing apparatus includes a vacuum chamber having a reaction space to generate plasma in which a target substrate is located, a low frequency antenna unit located outside the reaction space to generate plasma in the reaction space, a low frequency power supply to apply low frequency power to the low frequency antenna unit, a high frequency antenna unit located outside the reaction space to generate plasma in the reaction space, and a high frequency power supply to apply high frequency power to the high frequency antenna unit. The apparatus allows the ignition of plasma to be performed efficiently via the high frequency antenna unit, and improves efficiency of inductive coupling between plasma and a low frequency antenna via the low frequency antenna unit, thereby improving plasma generation efficiency.