Aspherical Optical Correction Components with Differential Speed Control
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Solution Overview
Problem
Existing optical correction arrangements in microlithography are inadequate in correcting optical aberrations that occur during the scanning process, particularly overlay errors caused by faulty surfaces and surface roughness, which lead to focal position displacement and complex field profiles that cannot be fully corrected by prior art solutions.
Innovation Solution
An optical correction arrangement with first and second correction components having aspherical surface contours that add up to zero in the zero position, where the first component is displaced at a faster speed than the second component, allowing for differential movement to effectively correct optical aberrations during scanning, including overlay errors, by compensating for focal position displacement and surface irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single correction component is used to correct optical aberrations, then the correction capability is limited, but the device complexity is reduced
Solution Approach 1:
The correction arrangement is divided into multiple correction components (first correction component and second correction component), each with independent aspherical surface contours. This segmentation allows each component to contribute differently to the overall correction, enabling more complex aberration correction than a single component could achieve, while resolving the contradiction between correction accuracy and device simplicity.
2Manufacturing precision
If correction components are displaced at the same speed, then the correction mechanism is simple, but the ability to correct dynamic aberrations during scanning is insufficient
Solution Approach 1:
The manipulator is designed to displace the first and second correction components at different speeds during scanning operations. This dynamic control allows the correction arrangement to adapt to the temporal characteristics of aberrations, providing effective correction for both static and dynamic optical errors without requiring overly complex control mechanisms.
3Reliability
If aspherical surface contours are designed to add up to zero in zero position, then the baseline optical performance is optimized, but the flexibility for dynamic correction is reduced
Solution Approach 1:
The aspherical surface contours of the correction components are designed with specific mathematical relationships where their parameters add up to zero in the zero position. This parameter design ensures that when components are in their neutral positions, they provide optimal baseline correction. When displaced, the parameters change dynamically, allowing the system to adapt to various aberration conditions and expand the correction range.
Data Source
AI summary
An optical correction arrangement includes a first and a second correction component arranged in succession along an optical axis. The first and the second correction components are provided with aspherical surface contours which at least approximately add up to zero overall in a zero position of the optical correction arrangement. The optical correction arrangement also includes a manipulator for displacing the first correction component in a first direction at a first speed and for displacing the second correction component in a second direction at a second speed. The first speed is greater than the second speed.