Extraction Body Surface Tension Lithography Liquid Control
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Solution Overview
Problem
In lithographic apparatuses, the immersion of substrates in liquid leads to challenges such as liquid reaching the underside of the substrate, causing turbulence and requiring additional motor power, and the existing fluid handling systems struggle to effectively manage and confine the liquid, resulting in unpredictable effects.
Innovation Solution
The introduction of an extraction body with a first passageway that creates a pressure environment lower than ambient pressure, utilizing surface tension to retain liquid within the passageway, and a second passageway for fluid extraction, which is decoupled from the object holder to manage liquid flow and minimize turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the substrate is immersed in a large body of liquid for lithographic exposure, then the liquid provides refractive index benefits for imaging smaller features, but the liquid must be accelerated with additional motor power and turbulence causes unpredictable effects
Solution Approach 1:
The patent divides the immersion liquid system into separate functional zones: a first region for supplying immersion liquid to the projection system, and a second region for removing liquid from beneath the substrate. This segmentation allows independent control of liquid supply and removal, reducing the total liquid volume that must be accelerated during substrate movement, thereby decreasing motor power requirements while maintaining imaging precision benefits.
Solution Approach 2:
The patent extracts liquid from beneath the substrate using a dedicated extraction system with extraction bodies positioned at the periphery of the substrate support table. This extraction mechanism removes liquid that would otherwise need to be accelerated during substrate movement, reducing the effective liquid mass that motors must move, thus lowering energy consumption while preserving the refractive index advantages in the imaging region.
2Measurement precision
If immersion liquid is supplied to the projection system, then imaging of smaller features is enabled through shorter wavelength in liquid, but liquid may reach the underside of the substrate causing turbulence and unpredictable effects
Solution Approach 1:
The patent introduces an intermediary extraction system positioned between the immersion liquid supply region and the substrate underside. This extraction system acts as a mediator that captures liquid before it can reach the substrate underside, preventing contamination and turbulence while allowing the immersion liquid to remain in the projection system for imaging precision benefits.
Solution Approach 2:
The patent extracts liquid from the region beneath the substrate using extraction bodies with extraction channels positioned at the periphery. This removal action prevents liquid from reaching the substrate underside, eliminating the harmful effects of liquid contamination and turbulence, while the immersion liquid continues to provide refractive index benefits in the imaging region.
3Ease of operation
If existing fluid handling systems are used to confine immersion liquid, then liquid supply is provided, but the systems struggle to effectively manage and confine the liquid resulting in unpredictable effects
Solution Approach 1:
The patent segments the fluid handling system into distinct functional components: a liquid supply system for providing immersion liquid to the projection system, and a separate liquid extraction system with extraction bodies positioned at the substrate support periphery. This segmentation provides reliable liquid confinement by creating independent control zones, preventing the unpredictable effects associated with integrated fluid handling systems.
Solution Approach 2:
The patent introduces an intermediary extraction system that acts as a reliable barrier between the immersion liquid supply and the substrate underside. This intermediary extraction mechanism reliably confines liquid within designated regions, preventing leakage and turbulence, thereby improving both ease of operation and reliability of liquid management.
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 solution reduces the amount of liquid reaching the underside of the substrate, decreases motor power requirements, and enhances the stability and control of liquid flow, thereby improving the precision and efficiency of the lithographic process.
Implementation Method 1
a second pressure in the first passageway associated with surface tension of the liquid is lower than the first pressure such that at least a portion of the liquid is retained in the first passageway
Data Source
AI summary
An extraction body for a support apparatus of a lithographic apparatus. The support apparatus is configured to support an object. The extraction body is formed with an opening at a surface thereof. The opening extends within the extraction body forming a first passageway. The first passageway is configured to fluidly communicate an extraction channel in the extraction body to liquid between the surface and the object. A first pressure in the extraction channel is less than ambient pressure. At least a part of the first passageway is sized and dimensioned such that when the liquid enters the first passageway via the opening, a second pressure in the first passageway associated with surface tension of the liquid is lower than the first pressure such that at least a portion of the liquid is retained in the first passageway.