Patterning Device Cooling via Independent Gas Momentum Control
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Solution Overview
Problem
Conventional lithographic apparatuses face challenges in achieving precise alignment and overlay accuracy due to thermal effects in patterning devices, which become more pronounced as device dimensions scale down, leading to alignment and overlay errors.
Innovation Solution
A patterning apparatus with a conditioning system featuring multiple gas outlets arranged at different distances perpendicular to the patterning device's surface, allowing for independent control of gas momentum to enhance temperature control and reduce thermal variations, thereby improving temperature uniformity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single gas outlet is used to provide gas flow over the patterning device surface, then the system structure is simple, but the temperature uniformity and control precision are insufficient
Solution Approach 1:
The single gas outlet is divided into multiple gas outlets (first gas outlet and second gas outlet) positioned at different locations. Each outlet can independently control gas flow parameters, enabling differentiated cooling zones to achieve uniform temperature distribution across the patterning device surface.
Solution Approach 2:
Different regions of the patterning device surface are provided with different gas flow characteristics by positioning gas outlets at different locations. This allows each region to receive optimized gas flow conditions tailored to its specific thermal requirements, improving overall temperature uniformity.
2Temperature
If gas flow rate is increased to improve cooling effect, then temperature control improves, but gas consumption and system complexity increase
Solution Approach 1:
The gas flow is divided into multiple independent streams from different outlets. This segmentation allows optimized gas flow distribution where each outlet contributes to cooling specific zones, improving overall cooling efficiency and reducing total gas consumption compared to a single outlet requiring high flow rates.
Solution Approach 2:
Instead of using one outlet with excessive gas flow, the system uses multiple outlets with appropriate partial flow rates. This partial action approach achieves better temperature control while minimizing gas consumption by distributing the cooling load across multiple sources.
3Manufacturing precision
If correction systems are used to compensate for thermal effects, then alignment accuracy is maintained, but system complexity and cost increase
Solution Approach 1:
The patent converts the harmful thermal effects into a controllable parameter by using gas flow to actively manage temperature distribution. Instead of correcting alignment errors after they occur, the system prevents thermal-induced misalignment by maintaining uniform temperature conditions, eliminating the need for complex correction systems.
Solution Approach 2:
The gas flow cooling system acts in advance to prevent thermal effects before they can cause alignment errors. By proactively controlling temperature distribution during the lithographic process, the system eliminates the need for post-hoc correction mechanisms.
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
The solution effectively reduces thermal-induced errors by creating a more uniform temperature distribution across the patterning device, enhancing alignment and overlay precision in lithographic processes.
Implementation Method 1
radiation from the radiation beam may also heat the gas around the support structure which may in turn heat the patterning device by convection heating
Data Source
AI summary
A patterning apparatus for a lithographic apparatus, the patterning apparatus including a patterning device support structure configured to support a patterning device having a planar surface; a patterning device conditioning system including a first gas outlet configured to provide a first gas flow over the planar surface in use and a second gas outlet configured to provide a second gas flow over the planar surface in use, wherein the first gas outlet and the second gas outlet are arranged at different distances perpendicular to the planar surface; and a control system configured to independently control a first momentum of gas exiting the first gas outlet and a second momentum of gas exiting the second gas outlet or to independently vary the first gas flow and/or the second gas flow over the planar surface of the patterning device.