Lithographic Substrate Table Gas Flow Control
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Solution Overview
Problem
Lithographic apparatuses face challenges in maintaining accurate pattern transfer and measurement at high moving speeds due to local fluctuations in ambient gas characteristics, which affect measurement and projection radiation beams, leading to positioning inaccuracies and imaging errors.
Innovation Solution
A lithographic apparatus with a physical component that undergoes movement relative to an enclosure, inducing a gas flow away from its surface, utilizing a flow direction system to direct ambient gas away from the surface, thereby reducing break-through of unconditioned gas into the protected volume and maintaining gas uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate moves at high speed during pattern transfer and measurement, then throughput is improved, but measurement precision and pattern transfer accuracy deteriorate due to ambient gas fluctuations
Solution Approach 1:
A gas barrier (intermediary layer) is introduced between the ambient gas and the measurement/projection regions. This gas barrier, formed by gas outlets on the substrate table, creates a protective gas layer that mediates the interaction between ambient gas fluctuations and the radiation beams, thereby maintaining measurement precision while allowing high-speed substrate movement for improved throughput.
2Productivity
If the substrate moves at high speed, then throughput is improved, but manufacturing precision deteriorates due to ambient gas affecting projection radiation beams
Solution Approach 1:
The gas barrier acts as an intermediary protective layer between the ambient gas environment and the projection radiation beams. By introducing conditioned gas through outlets on the substrate table, the system creates a stable gas environment that shields the projection process from ambient gas fluctuations, enabling high-speed operation without sacrificing pattern transfer accuracy.
Solution Approach 2:
The system changes the gas parameters (composition, temperature, pressure) in the protected volume by introducing conditioned gas through the gas barrier. This parameter modification creates a stable environment for the projection radiation beams, allowing high-speed substrate movement while maintaining manufacturing precision.
3Device complexity
If ambient gas is present in the enclosure, then device complexity is reduced, but measurement precision and manufacturing precision deteriorate due to gas fluctuations affecting radiation beams
Solution Approach 1:
The enclosure space is segmented into a protected volume and an ambient gas region by the gas barrier. The substrate table with its gas outlets creates a distinct protected zone where measurement and projection activities occur, separated from the ambient gas fluctuations. This segmentation allows the system to maintain simple enclosure structure while achieving high precision through localized gas control.
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 solution allows for higher scanning speeds while maintaining measurement accuracy, reducing the impact of ambient gas fluctuations on radiation beams and preventing break-through, thus enhancing the overall throughput and precision of the lithographic process.
Implementation Method 1
the movement induces a flow of the ambient gas relative to the component
Data Source
AI summary
A lithographic apparatus including: a projection system with an optical axis; an enclosure with an ambient gas; and a physical component accommodated in the enclosure, wherein: the lithographic apparatus is configured to cause the physical component to undergo movement relative to the enclosure, in a predetermined direction and in a plane perpendicular to the optical axis; the lithographic apparatus is configured to let the physical component maintain a predetermined orientation with respect to the enclosure during the movement; the movement induces a flow of the ambient gas relative to the component; the physical component has a surface oriented perpendicularly to the optical axis; the component includes a flow direction system configured to direct the flow of ambient gas away from the surface.