Lithography Flushing with Choked Gas Outlet for Faster Cleaning
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Solution Overview
Problem
The flushing process in lithographic apparatuses is time-consuming and inconsistent, leading to increased downtime and reduced uptime due to the need to accommodate varying pump qualities and the slow operation of mass flow controllers.
Innovation Solution
A flushing system with a choked gas outlet and pilot valves that decouple the gas flow from the pump quality, allowing for controlled pressure fluctuations and consistent gas flow rates, optimized by a controller to enhance cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow of gas is provided through the lithographic apparatus to remove contaminants, then the cleaning effectiveness is improved, but the flushing time increases and downtime increases
Solution Approach 1:
The patent changes the flow control parameter from mass flow controllers to a choked flow outlet. By configuring the gas outlet to choke the flow at a predetermined rate, the system achieves consistent and optimized gas flow rates without requiring slow-operating mass flow controllers to ramp up and down, thereby reducing flushing time while maintaining cleaning effectiveness.
2Productivity
If the gas flow rate is optimized for specific pump qualities, then the flushing process is improved, but the system becomes inconsistent across different pump specifications
Solution Approach 1:
The patent introduces a choked flow outlet as an intermediary component between the gas source and the pump. This outlet device mediates the gas flow by choking it at a predetermined rate, thereby decoupling the flow rate from the pump's capabilities. This allows the system to achieve consistent flushing performance across different pump specifications without requiring optimization for each pump type.
3Ease of operation
If mass flow controllers are used to control gas flow, then the flow rate can be regulated, but the operation becomes slow and downtime increases
Solution Approach 1:
The patent extracts the flow control function from the mass flow controllers and implements it through a choked flow outlet. By removing the need for mass flow controllers to ramp up and down, the system eliminates the time loss associated with their operation while maintaining the ability to regulate gas flow rate at the outlet.
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 system reduces flushing time and improves consistency, enabling faster and more thorough cleaning of lithographic apparatuses, thereby increasing operational efficiency and reducing downtime.
Implementation Method 1
a gas outlet configured to choke a flow of gas passing through the gas outlet at a predetermined rate
Implementation Method 2
controlled pressure fluctuations and consistent gas flow rates, optimized by a controller to enhance cleaning efficiency
Data Source
AI summary
There is provided a flushing system for a lithographic apparatus. said flushing system including a gas outlet configured to choke a flow of gas passing through the gas outlet at a predetermined rate. Also provided is a method of flushing a lithographic apparatus. the method including providing a flow of gas through the lithographic apparatus and operating a gas outlet from the lithographic apparatus such that the flow of gas is choked through the gas outlet.