Immersion Liquid Confinement Plate for Stable Lithography Meniscus
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Solution Overview
Problem
The presence of droplets and bubbles in immersion liquid during lithographic processes leads to defects on the substrate and increases maintenance downtime, limiting the availability of the lithographic apparatus.
Innovation Solution
A fluid handling system with replaceable plates and porous members that confine immersion liquid to a liquid confinement space, featuring fluid openings for supply and extraction, and bumper plates to maintain a minimal separation between the projection system and substrate, ensuring stable meniscus formation and preventing droplet formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If immersion liquid is used to improve resolution, then manufacturing precision is improved, but droplets and bubbles form causing defects
Solution Approach 1:
The patent employs a porous plate positioned between the projection system and substrate to manage immersion liquid. The porous structure allows controlled interaction with the liquid while preventing droplet formation and bubble entrapment, thus maintaining the resolution benefits of immersion lithography without the harmful effects of liquid instability.
Solution Approach 2:
The porous plate acts as an intermediary element between the immersion liquid and the substrate/projection system interface. It mediates the interaction by providing a structured interface that prevents direct contact issues between the liquid and optical components, eliminating droplet and bubble formation while preserving the refractive index benefits.
2Reliability
If fluid handling structure is maintained to prevent defects, then reliability is improved, but downtime increases
Solution Approach 1:
The fluid handling system is segmented into a reusable main structure and a replaceable porous plate component. This segmentation allows the plate to be quickly swapped out during maintenance without requiring extensive disassembly or complex cleaning procedures, reducing downtime while maintaining defect prevention capabilities.
Solution Approach 2:
The porous plate is designed as a consumable or easily replaceable component that can be discarded or quickly renewed rather than meticulously maintained. This approach prioritizes rapid replacement over lengthy maintenance cycles, minimizing downtime while ensuring consistent defect prevention performance.
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
Reduces downtime due to maintenance by stabilizing the meniscus and preventing droplet formation, thereby enhancing throughput and reducing defects on the substrate.
Implementation Method 1
The wavelength of this radiation determines the minimum size of features which are patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm and 13.5 nm. Further improvements in the resolution of smaller features may be achieved by providing an immersion fluid having a relatively high refractive index
Implementation Method 2
a replaceable plate with an outer surface that comprises a plurality of fluid openings configured for supply and/or extraction of immersion liquid and/or gas in a channel between the fluid handling system and the substrate; wherein the outer surface is coated
Data Source
AI summary
A fluid handling system for a lithographic apparatus, wherein the fluid handling system is 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 so that 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 replaceable plate with an outer surface that includes a plurality of fluid openings configured for supply and/or extraction of immersion liquid and/or gas in a channel between the fluid handling system and the substrate, wherein the outer surface is coated.