Movable Seal for Lithographic Immersion Liquid Gap Bridging
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Solution Overview
Problem
In lithographic apparatuses, the formation of bubbles in immersion liquid and loss of liquid from the immersion space lead to imaging errors and drying stains, respectively, due to the challenges of sealing and confining the liquid effectively during substrate movement.
Innovation Solution
A seal is used to bridge the gap between a table and a component in the lithographic apparatus, which is moveable relative to the table, and an under pressure source is applied to maintain the seal, preventing bubbles and liquid loss by forming a liquid-tight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If immersion liquid is used to fill the space between the final element and the substrate, then imaging precision is improved, but bubbles form and liquid is lost from the immersion space
Solution Approach 1:
A flexible seal member is positioned to bridge the gap between the movable component and the table, forming a liquid-tight seal that prevents bubbles from entering and liquid from escaping the immersion space while allowing for relative movement between components
2Productivity
If the substrate is moved relative to the projection system, then productivity is improved, but the seal between the table and component becomes challenging to maintain
Solution Approach 1:
The seal member is designed to be movable relative to the table, allowing it to maintain sealing contact with the movable component throughout its range of motion, thereby preserving seal integrity during substrate movement operations
3Reliability
If a seal is introduced to prevent bubbles and liquid loss, then reliability is improved, but device complexity increases
Solution Approach 1:
The movable seal member automatically maintains sealing contact through its own movement and the applied under pressure, eliminating the need for additional complex actuation mechanisms or control systems to preserve seal integrity
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 occurrence of bubbles and liquid loss, enhancing imaging accuracy and preventing drying stains by maintaining a consistent liquid environment during substrate processing.
Implementation Method 1
a seal to bridge a gap between the component and the table when the component is in a position relative to the table
Implementation Method 2
an under pressure source is applied to maintain the seal, preventing bubbles and liquid loss by forming a liquid-tight seal
Data Source
AI summary
A seal between a table and a component in a lithographic apparatus is disclosed. The seal bridges a gap between the component and the table when the component is in a position relative to the table. The component is moveable, in use, relative to the table and in an embodiment is attached to the table. The seal may be integral with the component or the table.