EUV Illumination System Mirror Module Orientation Adjustment
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Solution Overview
Problem
Mechanical installation tolerances in EUV illumination systems lead to deviations in mirror module orientations, preventing immediate attainment of desired optical performance after installation, despite precise manufacturing methods.
Innovation Solution
A method and system for systematically optimizing mirror positions by using measurement light to detect and adjust the orientation of mirror modules in six degrees of freedom, ensuring the illumination radiation meets specifications through integrated measurement technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mirror modules are installed in the illumination system, then the illumination beam path is established, but deviations in mirror module orientations occur due to mechanical installation tolerances, preventing immediate attainment of desired optical performance
Solution Approach 1:
The patent applies preliminary action by performing measurement and adjustment of mirror module orientations after installation. The measurement light is coupled into the illumination beam path and measurement values are detected to determine current orientations of mirror modules. Adjustment is then performed based on these measurements to achieve desired orientations, resolving the orientation deviations caused by mechanical installation tolerances.
2Reliability
If measurement and adjustment procedures are performed to correct mirror orientations, then optical performance is improved, but time and complexity are increased
Solution Approach 1:
The patent implements feedback by using measurement light to detect the current orientation of mirror modules and using these measurement values to determine adjustment actions. The measurement system provides feedback information about orientation deviations, and the adjustment mechanism responds to this feedback to correct the orientations, ensuring the illumination radiation fulfills illumination specifications.
Solution Approach 2:
The patent replaces complex mechanical alignment procedures with an optical measurement and adjustment system. Instead of relying solely on mechanical precision during installation, the system uses measurement light coupled into the illumination beam path to optically determine mirror orientations and automatically adjust them, substituting mechanical alignment complexity with optical measurement and control.
3Manufacturing precision
If mechanical installation tolerances are tightened to reduce orientation deviations, then manufacturing precision is improved, but installation difficulty and cost increase
Solution Approach 1:
The patent applies parameter changes by measuring and adjusting the orientation parameters of mirror modules after installation. Rather than enforcing strict installation tolerances, the system allows installation within broader tolerances and then corrects the orientation parameters through measurement and adjustment, changing the orientation parameters from their initial deviated values to the desired target values.
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
Enables targeted adjustment of the illumination system to achieve desired optical performance efficiently, allowing for precise alignment and maintenance, even after prolonged use or module replacement, thereby ensuring consistent and optimal EUV radiation distribution.
Implementation Method 1
detecting measurement light after reflection of the measurement light at each of the mirror modules of the illumination beam path
Data Source
AI summary
The disclosure relates to a method for producing an illumination system for an EUV apparatus in and to an illumination system for an EUV apparatus.