Lithographic Apparatus Radiation Beam Control for Substrate Position Errors
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Solution Overview
Problem
Lithographic errors occur due to changes in substrate position during exposure, leading to unintended pattern feature dimensions, as the radiation beam may not be in focus or have the desired intensity distribution, despite prior topography compensation.
Innovation Solution
A method and apparatus that determine the change in substrate position parallel to the radiation beam's direction and use this information to control radiation beam properties such as dose, bandwidth, wavelength, or focal properties in real-time to mitigate lithographic errors by adjusting the configuration of the lithographic apparatus components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is scanned during exposure, then productivity is improved, but manufacturing precision deteriorates due to unintended substrate movement toward or away from the projection system
Solution Approach 1:
The patent employs a feedback mechanism where the actual substrate position is measured during exposure and this information is used to adjust exposure parameters in real-time. The controller modifies the radiation beam properties based on the measured position deviations to compensate for focus errors and maintain pattern accuracy during substrate scanning.
Solution Approach 2:
The patent changes exposure parameters (such as radiation dose, focal position, or exposure timing) dynamically during the exposure process based on measured substrate position variations. This allows the system to adapt to position changes and maintain manufacturing precision while continuing to scan the substrate for improved productivity.
2Manufacturing precision
If real-time control of radiation beam properties is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces a controller as an intermediary component that receives position information from measurement devices and automatically adjusts radiation beam parameters. This intermediary simplifies the overall system architecture by centralizing the control logic and automating the coordination between measurement and exposure subsystems.
Data Source
AI summary
A method is disclosed. A change in position of a substrate in a direction substantially parallel to a direction of propagation of a radiation beam that is, or is to be, projected on to that substrate is determined, which change in position would result in a lithographic error in the application of a pattern to that substrate using that radiation beam. The change in position of the substrate is used to control a property of the radiation beam when, or as, the radiation beam is projected onto the substrate in order to reduce the lithographic error.