Movable Outer Fluid Handling Structure for Lithography Meniscus Stability
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Solution Overview
Problem
The throughput of lithographic apparatuses is limited due to the instability of the meniscus between the fluid handling structure and the substrate, leading to potential leaking of immersion fluid and defects on the substrate, which restricts the speed at which the substrate can be moved relative to the projection system.
Innovation Solution
A fluid handling structure with an inner and outer part, where the outer part is movable relative to the inner part in a specific plane, forming a variable space that changes shape but not the connecting space, ensuring the immersion fluid is contained within the variable space and preventing leakage, while allowing for faster substrate movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is moved at high speed relative to the projection system, then the throughput of the lithographic apparatus is improved, but the meniscus stability deteriorates causing immersion fluid leakage
Solution Approach 1:
The fluid handling structure is divided into a stationary inner part and a movable outer part that can move relative to each other in the scanning direction. This dynamic configuration allows the fluid handling structure to move synchronously with the substrate, maintaining meniscus stability at high scanning speeds while enabling high throughput operation
2Reliability
If the outer part of the fluid handling structure is made movable relative to the inner part, then the meniscus stability is improved, but the device complexity increases
Solution Approach 1:
The fluid handling structure is segmented into an inner part and an outer part that can move independently relative to each other. This segmentation allows the outer part to move with the substrate while the inner part remains stationary, maintaining meniscus stability without requiring complete movement of the entire fluid handling structure
Solution Approach 2:
The movable outer part and stationary inner part are combined to form a unified fluid handling structure that leverages the advantages of both configurations. The merging allows the system to achieve high-speed substrate movement capability while maintaining simple stationary mounting for the inner part
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 configuration stabilizes the meniscus, reducing the risk of fluid leakage and allowing for increased substrate movement speed, thereby enhancing the throughput of the lithographic apparatus without causing thermal variations or focus errors.
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, 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.
Data Source
AI summary
A fluid handling structure configured to confine immersion fluid to a region of a lithographic apparatus, the fluid handling structure comprising an aperture formed therein for the passage therethrough of a radiation beam through the immersion fluid, the aperture defining an immersion space to be filled with the immersion fluid, and an inner part and an outer part; wherein the inner part and the outer part are arranged so as to form therebetween a variable space and a connecting space that connects the variable space to the immersion space, wherein the outer part is movable relative to the inner part in a first plane so as to change in shape the variable space but not the connecting space, and wherein the fluid handling structure is configured to contain the immersion fluid in the variable space.