Toroidal Plasma Chamber Helical Gas Flow High Throughput
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Solution Overview
Problem
Existing toroidal plasma sources are limited in their ability to operate at high NF3 flow rates above 24 standard liters per minute, leading to localized high plasma impedance and gas flow instability, which restricts the throughput in applications like flat panel displays and solar panels.
Innovation Solution
A toroidal plasma chamber design with a broad gas plenum introducing process gas over a wide area, creating helical gas rotation through angled holes, and an outlet with a larger cross-sectional area to reduce impedance and instability, allowing for higher gas flow rates and improved gas-plasma interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If process gas is introduced through a single gas injection hole or multiple holes located in a small area in the plasma channel, then gas injection is simple, but localized high plasma impedance and gas flow instability occur
Solution Approach 1:
The gas injection system is segmented into multiple injection regions distributed along the plasma channel. Instead of using a single injection hole or a small cluster of holes, the patent divides the injection function across multiple locations, which distributes the gas flow and prevents localized high plasma impedance. This segmentation allows each injection point to operate at lower individual flow rates, maintaining plasma stability while achieving high overall gas flow rates.
Solution Approach 2:
The patent applies local quality by creating regions with different gas flow characteristics along the plasma channel. Different sections of the channel receive gas at different rates and angles, optimized for their specific location. This includes using angled holes in certain regions to create helical flow patterns that enhance mixing and prevent instability, while other regions use different injection geometries tailored to local plasma conditions.
2Productivity
If high gas flow rates are used to increase throughput, then productivity increases, but flow instabilities and plasma impedance increase
Solution Approach 1:
The high gas flow rate requirement is satisfied by segmenting the total flow across multiple injection points distributed along the plasma channel. Each injection point handles a portion of the total flow, preventing any single location from experiencing excessive flow rates that would cause instability. This allows the system to achieve high overall throughput (30 slm or higher NF3 flow rates) while maintaining stable plasma operation.
Solution Approach 2:
The patent introduces helical flow patterns by using angled injection holes that create rotation in the gas flow. This adds a rotational dimension to the otherwise linear flow through the plasma channel. The helical motion enhances gas-plasma interaction, improves mixing, and stabilizes the flow distribution, allowing high throughput operation without sacrificing plasma stability.
3Ease of manufacture
If conventional plasma chamber design is used, then manufacturing is simple, but NF3 flow capability is limited to below 24 slm
Solution Approach 1:
The plasma chamber is designed with multiple gas injection regions distributed along the plasma channel, allowing the system to handle high gas flow rates (30 slm or higher NF3) that would be impossible with conventional single-point injection designs. This segmented approach to gas distribution enables high productivity applications in flat panel display and solar panel manufacturing while maintaining a relatively simple overall chamber structure that can be manufactured using standard techniques.
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 design enables high flow rates of activated gases, enhancing process throughput and operational capability, extending NF3 flow capability to 30 slm or higher, while maintaining plasma stability and reducing turbulence.
Implementation Method 1
dissociation of inlet gas by the plasma
Implementation Method 2
gas-plasma interaction or dissociation rate of the process gas
Implementation Method 3
introducing the process gas over a broad area along the toroidal plasma channel
Implementation Method 4
providing a helical gas rotation in the plasma channel
Data Source
AI summary
A plasma chamber for activating a process gas, including at least four legs forming a toroidal plasma channel, each leg having a cross-sectional area, and an outlet formed on one leg, the outlet having a greater cross-sectional area than the cross-sectional area of the other legs. The plasma chamber further includes an inlet for receiving the process gas and a plenum for introducing the process gas over a broad area of the leg opposing the outlet to reduce localized high plasma impedance and gas flow instability, wherein the leg opposing the outlet defines a plurality of holes for providing a helical gas rotation in the plasma channel.