Immersion Liquid Extraction Layout for Stable High-Speed Lithography
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Solution Overview
Problem
The challenge in lithographic apparatuses is to increase throughput and reduce defects by effectively controlling the flows of immersion fluid during exposure processes.
Innovation Solution
A fluid handling system is implemented to confine immersion liquid to a liquid confinement space between the projection system and the substrate, utilizing a liquid extraction member and a liquid supply that extends around the perimeter of the confinement space, ensuring complete coverage and stable meniscus management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate moves faster to increase throughput, then productivity increases, but liquid instability and defects (droplet formation, gas bubbles) worsen
Solution Approach 1:
The liquid extraction member is designed to move synchronously with the substrate at the same speed, creating a dynamic system that maintains stable liquid confinement despite high-speed substrate movement. This dynamic coordination prevents liquid instability and defect formation while enabling increased throughput.
Solution Approach 2:
The liquid extraction member acts as an intermediary between the liquid confinement structure and the substrate, actively managing the liquid meniscus by extracting excess liquid and preventing droplet formation. This intermediary function stabilizes the liquid during high-speed substrate movement.
2Manufacturing precision
If immersion liquid is confined to a localized area, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The liquid extraction member functions as a flexible barrier that can adapt to the confined liquid space while maintaining precise control over liquid distribution. This flexible structure enables effective liquid confinement for high-resolution patterning without requiring overly complex rigid fluid handling systems.
3Reliability
If the liquid extraction member extracts liquid efficiently, then liquid stability improves, but the risk of gas bubble formation increases
Solution Approach 1:
The liquid extraction member is positioned and configured to provide feedback control of the liquid meniscus, continuously adjusting liquid extraction to maintain optimal liquid levels. This feedback mechanism stabilizes the liquid while preventing the conditions that lead to gas bubble formation during high-speed substrate movement.
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 system enhances throughput by allowing faster substrate movement while reducing the risk of liquid instability and defects, such as droplet formation and gas bubbles, thereby improving the overall performance of the lithographic apparatus.
Implementation Method 1
a liquid extraction member, having an inlet side and an outlet side, that is arranged to extract the immersion liquid from the liquid confinement space by a fluid flow from the inlet side to the outlet side
Implementation Method 2
providing an immersion fluid having a relatively high refractive index, such as water, on the substrate during exposure. The effect of the immersion fluid is to enable imaging of smaller features since the exposure radiation will have a shorter wavelength in the fluid than in gas. The effect of the immersion fluid may also be regarded as increasing the effective numerical aperture (NA) of the system and also increasing the depth of focus.
Data Source
AI summary
A fluid handling system for a lithographic apparatus, the fluid handling system configured to confine immersion liquid to a liquid confinement space between a part of a projection system and a surface of a substrate in the lithographic apparatus wherein a radiation beam projected from the projection system can irradiate the surface of the substrate by passing through the immersion liquid, the fluid handling system including: a liquid extraction member, having an inlet side and an outlet side, that is arranged to extract the immersion liquid from the liquid confinement space by a fluid flow from the inlet side to the outlet side; and a further liquid supply to the outlet side of the liquid extraction member arranged so that the outlet side receives liquid from a different source than the liquid confinement space.