Dynamic Fuel Control for Semiconductor Exhaust Gas Combustion
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Solution Overview
Problem
Existing exhaust gas abatement apparatuses, such as those using reducing flames, face inefficiencies in destroying high flow rates of exhaust gases from semiconductor processes, particularly with gases like ammonia, and result in excessive fuel consumption due to fixed fuel settings, and struggle to achieve high destruction and removal efficiency (DRE) for fluorine-containing cleaning gases.
Innovation Solution
The apparatus employs multiple exhaust gas combustion nozzles with adjustable fuel and oxidant supplies based on the chemistry of the exhaust gases, allowing for the modulation of combustion flames to optimize fuel usage and achieve high DRE rates by selectively varying the relative amounts of fuel and oxidant for each nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed amount of fuel is supplied to the combustion chamber to ensure high DRE for cleaning gases, then the destruction and removal efficiency for fluorine-containing gases is improved, but the fuel consumption increases excessively during deposition steps
Solution Approach 1:
The system dynamically adjusts the fuel supply amount based on the operational state of the process chamber. During deposition steps, a lower fuel supply is used, while during cleaning steps when fluorine-containing gases are present, the fuel supply is increased to ensure high DRE. This dynamic adjustment resolves the contradiction by making the fuel supply adaptive rather than fixed.
Solution Approach 2:
The control system receives information about the current process step (deposition or cleaning) and adjusts the fuel supply accordingly. This feedback mechanism allows the system to optimize fuel consumption during deposition while ensuring adequate fuel supply during cleaning operations to maintain high destruction and removal efficiency for hazardous gases.
2Object-generated harmful factors
If a reducing flame is used to destroy exhaust gases, then the harmful components are broken down, but high DRE is not achieved when high flow rates of ammonia-containing exhaust gas are received
Solution Approach 1:
The system changes the chemical parameters of the combustion process by switching between reducing and oxidizing flame conditions. For ammonia-containing exhaust gases at high flow rates, an oxidizing flame is used instead of a reducing flame to achieve high DRE. This parameter change allows the system to handle different types of exhaust gases effectively.
Solution Approach 2:
The combustion chamber can create different local combustion conditions (reducing or oxidizing) depending on the type of exhaust gas being processed. This local quality adjustment allows optimal destruction of different harmful components - reducing conditions for certain gases and oxidizing conditions for ammonia, thereby achieving high DRE across various gas compositions.
3Reliability
If the fuel supply is pre-set for maximum cleaning gas flow rate, then high DRE is ensured for cleaning gases, but the apparatus operates with higher fuel usage than required for deposition processes
Solution Approach 1:
The fuel supply is made dynamic rather than pre-set at maximum levels. The control system adjusts the fuel supply amount in real-time based on whether the process chamber is in deposition or cleaning mode, ensuring adequate DRE during cleaning while minimizing fuel consumption during deposition operations.
Solution Approach 2:
Instead of always supplying excessive fuel at maximum levels, the system supplies the appropriate amount of fuel needed for each operational phase. During deposition, partial fuel supply is sufficient, while during cleaning, the full fuel capacity is utilized to ensure high DRE, thus avoiding continuous excessive fuel usage.
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 approach enhances the destruction rate efficiency of exhaust gases, optimizes fuel consumption, and allows for the efficient treatment of various exhaust gases, including ammonia and fluorine-containing gases, while minimizing fuel usage and operating costs.
Implementation Method 1
burning the exhaust gas received from the process chamber to destroy the harmful components of the exhaust gas
Implementation Method 2
react to form a thin film over the surface of the substrate
Data Source
AI summary
Apparatus is described for combusting exhaust gases output from a plurality of process chambers. The apparatus comprises a plurality of exhaust gas combustion nozzles (22) connected to a combustion chamber (24). Each nozzle receives a respective exhaust gas (26), and comprises means for receiving a fuel (40) and an oxidant (30) for use in forming a combustion flame within the chamber. A controller receives data indicative of the chemistry of the exhaust gas supplied to each nozzle, and adjusts the relative amounts of fuel and oxidant supplied to each nozzle in response to the received data. This can enable the nature of each combustion flame to be selectively modified according to the nature of the exhaust gases to be destroyed by that flame, thereby enhancing the destruction rate efficiency of the exhaust gas and optimising fuel consumption.