Lithographic Apparatus Wall Cooling for EUV Contamination Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithographic apparatuses using EUV radiation face contamination issues due to the presence of contaminants like hydrogen and water, which degrade materials, reduce power, and necessitate complex and expensive gas handling systems, while existing gas flushing methods are inefficient and costly.
Innovation Solution
Cooling internal walls of the lithographic apparatus to a temperature below that of the optical components, creating a temperature differential that causes contaminants to condense on the walls instead of the optical components, thereby reducing contamination and eliminating the need for hydrogen within the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gas flushing methods are used to remove contaminants, then contamination of optical components is reduced, but device complexity and cost increase due to complex gas handling systems
Solution Approach 1:
The patent changes the temperature parameter of the internal walls to below the condensation point of contaminants, causing contaminants to preferentially condense on the cooled walls rather than on optical components. This temperature parameter change eliminates the need for complex gas handling systems while effectively reducing contamination.
Solution Approach 2:
Instead of trying to remove or flush away contaminants using complex gas systems, the patent converts the harmful condensation process into a beneficial one by directing contaminants to condense on predetermined sacrificial surfaces (internal walls) rather than on critical optical components. The harm of condensation is redirected to protect the optical system.
2Object-affected harmful factors
If hydrogen gas is used to flush contaminants, then contamination is reduced, but power is reduced due to EUV radiation absorption by hydrogen
Solution Approach 1:
The patent changes the temperature parameter of internal walls to create a condensation gradient that directs contaminants away from the EUV beam path and optical components. This eliminates the need for hydrogen gas flushing, thereby preventing EUV radiation absorption and maintaining full power transmission.
3Object-affected harmful factors
If complex gas handling systems are implemented, then contamination control is improved, but manufacturing cost increases
Solution Approach 1:
The patent implements a simple temperature control system that cools internal walls to a specific temperature range to achieve contaminant condensation redirection. This replaces complex gas handling systems with a straightforward thermal management approach, significantly reducing manufacturing cost while maintaining effective contaminant control.
4Device complexity
If materials are used without protective capping layers, then device complexity is reduced, but material degradation occurs due to hydrogen exposure
Solution Approach 1:
The patent eliminates hydrogen gas exposure by using cooled internal walls to redirect contaminant condensation. This removes the harmful hydrogen environment that would require protective capping layers, allowing materials to be used without such layers while maintaining reliability and preventing degradation.
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 method improves overlay accuracy, extends the lifetime of components, and allows the use of materials that would otherwise be unusable, while reducing the complexity and cost of gas handling systems.
Implementation Method 1
cooling at least a portion of the at least one internal wall to a temperature below that of the at least one optical component such that during use of the cooling apparatus at least one contaminant within the housing rests preferentially on the internal wall relative to the optical component
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A lithographic apparatus arranged to project a pattern from a patterning device onto a substrate, comprising at least one housing comprising at least one internal wall, at least one optical component arranged within at least one chamber defined at least in part by the at least one internal wall and configured to receive a radiation beam and a cooling apparatus arranged to cool at least a portion of the at least one internal wall to a temperature below that of the at least one optical component.