Separate Gas Channel Structure to Suppress Parasitic Plasma
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Solution Overview
Problem
Plasma processing apparatuses face issues with high RF power consumption and easy generation of parasitic plasma in insulating tubes, leading to potential rupture or damage due to electrolysis and film accumulation, which increases power consumption and pollutes the ceramic tubes.
Innovation Solution
A structure with separate gas channels for process and cleaning gases, where the cleaning gas is fed through a wide-bore tube to create a high-pressure environment and an on-off valve is used to disconnect the paths before deposition, preventing parasitic plasma formation by maintaining a small inner diameter for the process gas path and using inert gases like nitrogen trifluoride or argon for cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the diameter of the ceramic tube is increased to ensure sufficient cleaning gas flow, then cleaning gas delivery is improved, but parasitic plasma generation and tube damage risk increase
Solution Approach 1:
The gas delivery system is segmented into separate channels: a first gas channel with a narrow-bore insulating tube for process gas, and a second gas channel with a wide-bore insulating tube for cleaning gas. This segmentation allows each channel to be optimized independently, enabling sufficient cleaning gas flow through the wide-bore tube while maintaining tube integrity by preventing parasitic plasma in the process gas channel.
Solution Approach 2:
A valve is introduced as an intermediary component to control and isolate the cleaning gas channel from the process gas channel. The valve enables selective delivery of cleaning gas through the wide-bore tube when needed, while preventing it from continuously flowing through the narrow-bore process gas tube, thus avoiding parasitic plasma generation.
2Productivity
If high RF power is supplied to improve deposition performance, then film deposition efficiency is improved, but parasitic plasma generation in the insulating tube increases
Solution Approach 1:
The system segments the gas pathways so that high RF power can be applied to the process gas channel to improve deposition efficiency, while the cleaning gas channel with its separate wide-bore tube does not suffer from parasitic plasma issues, allowing safe operation at high power levels.
3Device complexity
If a common ceramic tube is used for both process gas and cleaning gas, then device complexity is reduced, but parasitic plasma pollution and tube rupture risk increase
Solution Approach 1:
The single common ceramic tube is segmented into two separate gas channels with distinct narrow-bore and wide-bore insulating tubes. This segmentation eliminates parasitic plasma pollution by preventing cleaning gas from flowing through the narrow process gas channel, while accepting the increased device complexity as a necessary trade-off for reliability.
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 reduces the likelihood of breakdown and parasitic plasma generation, minimizing the risk of tube rupture and damage while ensuring stable cleaning gas delivery, thereby enhancing the operational safety and efficiency of the plasma processing apparatus.
Implementation Method 1
A radio-frequency (RF) power source coupled to the vacuum chamber provides RF power to the vacuum chamber, and excites the process gas into plasma
Implementation Method 2
The excited gas is attached to the substrate surface to react and form a film or layer
Implementation Method 3
the substrate is maintained at a specific temperature by a heating device
Data Source
AI summary
The present disclosure provides a structure and a method for solving parasitic plasma in a plasma processing apparatus, which belong to the field of plasma processing apparatus. In the structure, a first gas channel is in communication with a narrow-bore insulating tube and a second gas channel. The narrow-bore insulating tube is configured to feed a process gas into a gas distribution assembly. An on-off valve is disposed between the second gas channel and the first gas channel. The second gas channel is configured to feed a cleaning gas into the gas distribution assembly. Therefore, on the one hand, the on-off valve can be closed before the processing, and a cleaning gas with a preset pressure can be fed into the wide-bore insulating tube and the second gas channel, thereby forming a relatively high-pressure environment in the wide-bore insulating tube and the second gas channel. On the other hand, the gas paths of the process gas and the cleaning gas are separate from each other, so that the path of the process gas can have a relatively small inner diameter, thereby preventing electrolysis of the process gas and generation of parasitic plasma before the process gas entering into the processing chamber, which effectively reduces the probability of rupture or damage of the insulating tube caused by the parasitic plasma.