Optical Imaging Arrangement with Differential Active Support
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Solution Overview
Problem
The miniaturization of semiconductor devices necessitates enhanced resolution and increased numerical aperture in optical systems, leading to challenges in maintaining line of sight accuracy and dynamic control due to large optical elements, which results in reduced resonant frequencies, increased thermal loads, and vibration-induced errors.
Innovation Solution
A modified support strategy where the largest and heaviest optical element is actively supported at a low control bandwidth, allowing other elements to follow its movements, maintaining a stable spatial relationship, and shifting nodal points for improved metrology component placement, thereby reducing the need for high control bandwidth across all components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high numerical aperture is used to achieve enhanced resolution, then imaging accuracy is improved, but line of sight accuracy requirement becomes more stringent
Solution Approach 1:
The patent implements dynamic support strategies where optical elements are actively controlled to maintain their positions. The support devices adjust in real-time to compensate for disturbances, enabling the system to achieve and maintain the stringent line of sight accuracy required for high numerical aperture operation.
Solution Approach 2:
The patent changes the control bandwidth parameter differently for different optical elements. The largest optical element is controlled at a lower bandwidth while smaller elements are controlled at higher bandwidths, optimizing the balance between stability and responsiveness to maintain imaging accuracy.
2Manufacturing precision
If large optical elements are used to increase numerical aperture, then imaging accuracy is improved, but resonant frequency decreases
Solution Approach 1:
The patent actively controls optical elements with lower resonant frequencies through dynamic support devices that compensate for vibrations and positional drift. This allows large optical elements necessary for high numerical aperture to be used without being limited by their lower resonant frequencies.
Solution Approach 2:
The patent implements differential control bandwidth allocation where the largest optical element with the lowest resonant frequency is controlled at a lower bandwidth, while smaller elements with higher resonant frequencies are controlled at higher bandwidths, optimizing overall system performance.
3Stability of the object's composition
If conventional support strategy is used for all optical elements, then individual stability is maintained, but system complexity increases
Solution Approach 1:
The patent applies different support and control strategies to different optical elements based on their individual characteristics. The largest optical element receives specialized low-bandwidth control while smaller elements receive high-bandwidth control, optimizing stability for each component without uniformly increasing system complexity.
Solution Approach 2:
The patent segments the control system into different bandwidth levels, with the largest optical element controlled at low bandwidth and smaller elements controlled at high bandwidth. This segmentation allows tailored support strategies that reduce overall system complexity while maintaining individual stability.
Data Source
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AI summary
There is provided an optical imaging arrangement comprising an optical projection unit and a control device. The optical projection unit comprises a support structure and a group of optical element units adapted to transfer, in an exposure process using exposure light along an exposure light path, an image of a pattern of a mask unit onto a substrate of a substrate unit. The group of optical element units comprises a first optical element unit and a plurality of second optical element units, the first optical element unit and the second optical element units, under a control by said control device, being actively supported by the support structure. The first optical element unit is actively supported at a low first control bandwidth, while the second optical element units are actively supported at a second control bandwidth to substantially maintain a given spatial relationship of each of the second optical elements with respect to the first optical element unit.