Segmented Fluid Handling Structure for Immersion Lithography
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Solution Overview
Problem
The existing fluid handling structures in lithographic apparatuses are too stiff, leading to focusing errors due to variations in distance from the substrate, which affects the precision of the liquid supply and extraction processes.
Innovation Solution
A fluid handling structure with a supply opening and an extraction opening on a first portion of the undersurface, where the first portion is at a different distance from the facing surface than a second portion, and the undersurface is designed to be at most 10 mm in length in the radial direction, reducing stiffness and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the fluid handling structure is made rigid to maintain structural integrity, then structural stability is improved, but focusing precision deteriorates due to stiffness variations
Solution Approach 1:
The fluid handling structure is divided into multiple segments: a first portion with supply and extraction openings that is closer to the substrate, and a second portion that is further from the substrate. This segmentation allows different regions to serve different functions - the first portion handles fluid management while the second portion maintains optical clarity and minimal interference with focusing, thereby resolving the contradiction between structural stability and focusing precision.
2Productivity
If the fluid handling structure is positioned close to the substrate for effective liquid handling, then liquid handling efficiency is improved, but optical interference increases affecting focusing
Solution Approach 1:
The structure is segmented into a first portion positioned close to the substrate for effective liquid handling through supply and extraction openings, and a second portion positioned further from the substrate to minimize optical interference. This spatial segmentation allows the structure to be close to the substrate for efficiency while maintaining optical performance for focusing.
Solution Approach 2:
The invention transitions from a single-plan fluid handling structure to a three-dimensional configuration where the first and second portions are at different distances from the substrate along the optical axis. This dimensional change allows the structure to fulfill both liquid handling requirements (close to substrate) and optical requirements (further from substrate) simultaneously.
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 design reduces the stiffness of the fluid handling structure, minimizing focusing errors and maintaining the stability of the meniscus between the substrate and the fluid handling structure, enhancing the precision of the liquid handling process.
Implementation Method 1
a supply opening configured to supply liquid toward the substrate
Implementation Method 2
an extraction opening configured to remove fluid from between the fluid handling structure and the substrate
Implementation Method 3
maintaining the stability of the meniscus between the substrate and the fluid handling structure
Data Source
AI summary
A fluid handling structure configured to supply and confine immersion liquid to a space defined between a projection system and a facing surface facing the fluid handling structure is disclosed. A first portion of an undersurface of the fluid handling structure, in use, is a different distance from the facing surface than a second portion of the undersurface. Further, the first portion has defined in it a supply opening configured to supply liquid toward the facing surface, and an extraction opening configured to remove fluid from between the fluid handling structure and the facing surface.