Removable Planar Member for Lithography Thermal Control
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Solution Overview
Problem
Lithographic apparatuses face challenges in achieving accurate thermal conditioning due to localized heating or cooling issues, such as hot spots in dry systems, cold spots in immersion systems, and difficulties in extreme ultraviolet radiation systems, particularly due to gaps between temperature sensors/heaters and the substrate.
Innovation Solution
A removable planar member with integrated heaters and sensors, potentially using carbon nanotubes, is mounted on a burl plate to improve thermal transfer by reducing thermal resistance and allowing for local thermal conditioning, which can be applied to substrates or other objects within the lithographic apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fluid-based global substrate table conditioning system is used, then thermal conditioning is provided, but localized thermal control is insufficient due to gaps between the substrate and burl plate surface
Solution Approach 1:
The patent applies local quality by transitioning from a uniform global substrate table conditioning system to a localized thermal control system. Individual heaters and temperature sensors are placed at specific locations on the burl plate surface, allowing different regions to be independently controlled. This enables targeted thermal correction of localized issues such as hot spots or cold spots that a global system cannot address effectively.
Solution Approach 2:
The patent introduces an intermediary layer (the burl plate with integrated heaters and sensors) between the substrate table conditioning system and the substrate. This intermediary provides direct thermal contact and control at the substrate-burl plate interface, bridging the gap between the fluid-based global system and the substrate surface, thereby enabling precise local thermal management.
2Temperature
If heaters and sensors are deposited on the burl plate between burls, then local thermal conditioning is achieved, but thermal transfer efficiency is reduced by the gap between the burl plate surface and substrate
Solution Approach 1:
The patent addresses the gap issue by extending heaters and sensors vertically from the burl plate surface toward the substrate, utilizing the vertical dimension. This dimensional approach allows thermal contact to be established across the gap space, improving thermal transfer efficiency while maintaining the localized control capability provided by the distributed heater-sensor array.
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 enhances thermal conditioning by reducing thermal distance and increasing the effective thermal area, improving the accuracy and speed of temperature control and yield in lithographic processes.
Implementation Method 1
a plurality of carbon nanotubes extending towards the first object with an axis substantially aligned with a direction perpendicular to a surface of the first object so as to improve thermal transfer to/from the first object
Implementation Method 2
the removable member comprising at least one heater and at least one temperature sensor
Data Source
AI summary
A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate, the lithographic apparatus having a first object and a planar member mounted on the first object to improve thermal transfer to/from a second object.