Fluid Handling Structure Meniscus Pinning Gas Knife
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Solution Overview
Problem
In lithographic apparatuses, the fluid handling system faces challenges in maintaining high scanning speed without significant liquid loss, which can lead to imaging defects due to gas bubbles forming between the substrate and the fluid handling structure, causing errors in the projection process.
Innovation Solution
A fluid handling structure with liquid supply and extraction openings is designed to provide and remove liquid from the undersurface, incorporating a meniscus pinning feature and a gas knife device to manage the meniscus and prevent gas bubbles from entering the projection path, ensuring efficient liquid handling and minimizing imaging errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scanning speed is increased to improve productivity, then throughput is improved, but liquid loss increases causing gas bubbles to form and create imaging defects
Solution Approach 1:
The gas knife device is positioned upstream (in the scanning direction) of the liquid meniscus to preemptively remove gas bubbles before they can enter the projection path. This preliminary action prevents the formation of gas bubbles that would otherwise cause imaging defects at high scanning speeds.
Solution Approach 2:
The gas knife introduces a controlled gas flow as an intermediary mechanism between the liquid meniscus and the projection path. This gas flow acts as a mediator to selectively remove harmful gas bubbles while maintaining the liquid immersion environment necessary for high-resolution imaging.
2Manufacturing precision
If liquid is confined to a localized area to improve manufacturing precision, then pattern transfer accuracy is improved, but liquid loss control becomes more difficult
Solution Approach 1:
The liquid confinement system is segmented into a localized immersion area defined by the liquid confinement structure, separating the immersion liquid from the bulk environment. This segmentation enables precise pattern transfer while the gas knife and extraction openings provide controlled liquid management at the boundaries of the confined region.
Solution Approach 2:
Different regions of the fluid handling structure have different functions: the central region confines liquid for precise imaging, while the peripheral regions (with extraction openings and gas knife) manage liquid removal and gas bubble elimination. This local differentiation of quality and function resolves the contradiction between localized confinement and liquid loss control.
3Reliability
If a meniscus pinning feature is added to control liquid meniscus to reduce imaging defects, then reliability is improved, but device complexity increases
Solution Approach 1:
The meniscus pinning feature is extracted as a distinct functional element from the liquid confinement structure. This separate feature specifically addresses meniscus control and gas bubble prevention, improving reliability without requiring a complete redesign of the entire fluid handling system.
Solution Approach 2:
The meniscus pinning feature is integrated with the liquid confinement structure and gas knife device to form a cohesive fluid handling system. This merging combines multiple functions (liquid confinement, meniscus control, gas bubble removal) into a unified structure that achieves high reliability without proportionally increasing complexity.
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 enables faster scanning speeds while reducing the likelihood of imaging defects by effectively managing liquid and gas interactions, ensuring consistent and accurate pattern transfer onto the substrate.
Implementation Method 1
a gas knife device to generate a gas flow to remove liquid droplets from a surface facing the projection system
Implementation Method 2
a liquid supply opening or a plurality of liquid supply openings and a liquid extraction opening or a plurality of liquid extraction openings arranged such that, in use, liquid is provided on and removed from the undersurface of the fluid handling structure
Implementation Method 3
a meniscus pinning feature to pin a meniscus which extends between the fluid handling structure and a facing surface which faces the fluid handling structure
Data Source
AI summary
A fluid handling structure for a lithographic apparatus is disclosed. The fluid handling structure has, on an undersurface, a liquid supply opening or a plurality of liquid supply openings and a liquid extraction opening or a plurality of liquid extraction openings arranged such that, in use, liquid is provided on and removed from the undersurface of the fluid handling structure.