Lithographic Apparatus Shielding for Target Portion Irradiation
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Solution Overview
Problem
Liquidphobic materials used in lithographic apparatuses degrade when irradiated with radiation, leading to loss of their properties and potential contamination, which affects the stability and accuracy of the immersion liquid meniscus and the substrate table's movement.
Innovation Solution
A lithographic apparatus with a moveable framing member that restricts the cross-section of the radiation beam to prevent irradiation of the surface material between target portions, thereby reducing degradation and maintaining the liquidphobic properties of the surface material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the radiation beam cross-section is enlarged to irradiate multiple target portions simultaneously, then productivity is improved, but the surface material between target portions degrades due to excessive irradiation
Solution Approach 1:
The patent segments the radiation beam cross-section into multiple discrete irradiation regions corresponding to individual target portions. By using a mask with separated openings or a scanning mechanism that divides the beam path, the system can irradiate multiple target portions simultaneously while preventing radiation from reaching the surface material between them, thus resolving the contradiction between productivity and surface material stability
Solution Approach 2:
The patent applies local quality by creating non-uniform irradiation distribution across the substrate surface. The radiation beam is configured to provide intense localized irradiation only to the target portions while completely avoiding the surface material between them. This selective irradiation pattern allows simultaneous processing of multiple targets without degrading the inter-target surface material, thereby maintaining both productivity and reliability
2Reliability
If the radiation beam cross-section is restricted to avoid surface material irradiation, then surface material stability is improved, but the area of target portions that can be irradiated simultaneously is reduced
Solution Approach 1:
The patent employs dynamic control of the radiation beam configuration to adaptively manage the irradiation pattern. By using movable masks, adjustable aperture systems, or scanning mechanisms that can dynamically reconfigure the beam cross-section, the system achieves simultaneous irradiation of multiple target portions while maintaining precise avoidance of surface material between them, thus resolving the contradiction between irradiation area and surface material stability
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 limits the irradiation of the surface material between target portions, reducing degradation and heat-induced deformation, thus maintaining the stability of the immersion liquid meniscus and enhancing the accuracy and speed of substrate table movement.
Implementation Method 1
Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate
Implementation Method 2
enable imaging of smaller features since the exposure radiation will have a shorter wavelength in the liquid
Data Source
AI summary
A lithographic apparatus is disclosed that includes a table, at least two target portions on the table or on an object on the table, and a surface material between the at least two target portions. The apparatus further includes an optical system configured to project a beam of radiation, along an optical path towards the table, with a cross-section to irradiate the at least two target portions at the same time. The apparatus further includes a shield moveable into the optical path to restrict the cross-section of the beam of radiation to restrict illumination between the at least two target portions, wherein the surface material between the at least two target portions would degrade when irradiated with radiation from the optical system.