Immersion Lithography Fluid Handling Structure for Meniscus Stability
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Solution Overview
Problem
In lithographic apparatuses, the confinement of immersion liquid can lead to meniscus instability, resulting in bubbles that interfere with the projection beam and cause imaging errors.
Innovation Solution
A fluid handling structure with a meniscus pinning feature and gas supply and recovery openings is used to stabilize the meniscus, preventing its radial outward passage and maintaining immersion fluid within a controlled area. This structure includes a cornered shape with varying radii of curvature and a fluid supply/recovery system that adjusts fluid flow rates around the periphery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If immersion liquid is confined to a localized area on the substrate surface, then imaging precision is improved, but meniscus instability occurs leading to bubble formation
Solution Approach 1:
The gas supply system is divided into multiple gas supply openings distributed around the periphery of the immersion liquid confinement area. This segmentation allows localized gas flow control at different positions, enabling precise meniscus stabilization without disrupting the overall confined liquid structure, thus preventing bubble formation while maintaining imaging precision
Solution Approach 2:
Gas flow is applied locally at the periphery of the immersion liquid confinement area through multiple gas supply openings. This local gas flow creates localized pressure that stabilizes the meniscus at critical positions without affecting the bulk immersion liquid, thereby maintaining both meniscus stability and imaging precision
2Stability of the object's composition
If gas flow rate is increased to stabilize meniscus, then meniscus stability is improved, but liquid escape may occur
Solution Approach 1:
Gas flow is applied partially at controlled rates through multiple gas supply openings rather than excessive uniform gas flow. This partial action provides sufficient meniscus stabilization while avoiding over-pressurization that could cause liquid escape, achieving the right balance between stability and substance retention
Solution Approach 2:
The gas flow rate is controlled based on feedback from the meniscus position and liquid confinement status. The system adjusts gas flow dynamically to maintain meniscus stability without exceeding the threshold that would cause liquid escape, implementing a self-regulating mechanism
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 effectively reduces the likelihood of bubble formation, enhancing imaging stability and precision by maintaining the meniscus stability and preventing liquid escape, thus improving the accuracy of the lithographic process.
Implementation Method 1
at least one gas supply opening at least partly surrounding and radially outward of the meniscus pinning feature
Implementation Method 2
A fluid handling structure with a meniscus pinning feature and gas supply and recovery openings is used to stabilize the meniscus, preventing its radial outward passage
Implementation Method 3
the confinement of immersion liquid can lead to meniscus instability
Implementation Method 4
a meniscus pinning feature to resist passage of immersion liquid in a radially outward direction from the space
Implementation Method 5
a fluid supply/recovery system that adjusts fluid flow rates around the periphery
Data Source
AI summary
A fluid handling structure for a lithographic apparatus, the fluid handling structure having, at a boundary of a space configured to contain immersion fluid to a region external to the fluid handling structure: a meniscus pinning feature to resist passage of immersion fluid in a radially outward direction from the space; a gas supply opening at least partly surrounding and radially outward of the meniscus pinning feature; and optionally a gas recovery opening radially outward of the gas supply opening, wherein the gas supply opening, or the gas recovery opening, or both the gas supply opening and the gas recovery opening, has an open area per meter length which has a variation peripherally around the space.