Decoupled Extraction Body for Immersion Lithography Thermal Stability
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Solution Overview
Problem
Lithographic apparatuses face challenges in maintaining the stability of the temperature profile of object holders due to the handling of immersion liquids, which can lead to thermal and mechanical decoupling issues and deformation of substrates during imaging processes.
Innovation Solution
A support apparatus with an extraction body and a seal device that is decoupled from the object holder and table, featuring a flexible member to seal gaps and extract fluid, reducing thermal and mechanical coupling and improving temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is immersed in a large body of liquid for lithographic exposure, then the refractive index is improved for smaller feature imaging, but the liquid handling creates thermal and mechanical coupling issues leading to temperature instability
Solution Approach 1:
The patent divides the liquid handling system into separate functional zones: a liquid supply region, a liquid confinement region with the substrate, and a liquid extraction region. This segmentation allows the substrate to be exposed to immersion liquid for improved imaging while preventing the entire substrate table from being submerged, thereby reducing thermal coupling and improving temperature stability during scanning exposure.
Solution Approach 2:
The patent extracts the liquid handling function from a large-scale substrate table immersion approach and concentrates it into a localized region around the substrate. By extracting only the necessary amount of liquid into a confined space and providing extraction paths for liquid removal, the system achieves the refractive index benefits of immersion lithography while minimizing thermal loads on the substrate holder.
2Productivity
If the substrate table is accelerated during scanning exposure with immersion liquid, then the productivity is improved for higher throughput, but the liquid handling creates turbulence and unpredictable effects
Solution Approach 1:
The patent segments the liquid containment into a localized confinement region that is decoupled from the moving substrate table. This allows the substrate table to be accelerated during scanning exposure while the immersion liquid remains confined in a stable region, preventing turbulence and unpredictable liquid behavior during high-speed scanning operations.
Solution Approach 2:
The patent introduces a liquid confinement structure as an intermediary between the moving substrate table and the immersion liquid. This mediator allows the table to move at high speeds for improved productivity while the confinement structure maintains stable liquid positioning, preventing turbulence and ensuring consistent imaging conditions during scanning exposure.
3Device complexity
If the extraction body is coupled to the object holder for fluid extraction, then the fluid handling is simplified, but the thermal and mechanical coupling causes deformation of the substrate
Solution Approach 1:
The patent extracts the extraction body from the object holder structure, creating a decoupled configuration. The extraction body is positioned to access and remove immersion liquid from the confinement region without being mechanically or thermally coupled to the object holder. This allows simplified fluid extraction functionality while preventing thermal coupling from causing substrate deformation during imaging.
Solution Approach 2:
The patent introduces a thermal isolation mechanism as an intermediary between the extraction body and the object holder. This mediator enables the extraction body to perform its fluid handling function while preventing thermal energy transfer that would otherwise cause mechanical coupling and substrate deformation, thereby maintaining manufacturing precision.
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 solution enhances the stability of the temperature profile of the object holder and reduces thermodynamic loads on the substrate, minimizing deformation and imaging errors caused by fluid handling.
Implementation Method 1
the seal device comprises a flexible member which is fixed to only one of the extraction body and the object holder
Implementation Method 2
the extraction body comprising an extraction opening configured to extract fluid
Implementation Method 3
the extraction body is spaced from both the object holder and the object table such that the extraction body is substantially decoupled from both the object holder and the object table
Data Source
AI summary
A support apparatus for a lithographic apparatus has an object holder and an extraction body radially outward of the object holder. The object holder is configured to support an object. The extraction body includes an extraction opening configured to extract fluid from a top surface of the support apparatus. The extraction body is spaced from the object holder such that the extraction body is substantially decoupled from the object holder. The extraction body includes a projection configured such that it surrounds the object holder and such that, in use, a layer of immersion liquid is retained on the projection and in contact with an object supported on the object holder.