Optical Module Measuring Device Decoupling
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Solution Overview
Problem
In microlithography, existing optical systems face challenges in accurately positioning and orienting optical elements due to increased requirements for precision and minimization of imaging errors, particularly with the deformation of optical elements leading to unnecessary corrections and complications in achieving high resonant frequencies and dynamic control.
Innovation Solution
An optical module with an optical element unit that includes a support device, deformation device, and measuring device, where the measuring device is decoupled from the deformation section to prevent propagation of deformation stresses, allowing for precise determination and correction of the optical element's rigid body position and orientation in all degrees of freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the optical element and the deformation device form one unit, then the deformation can be applied directly to the optical element, but the unit becomes heavy and requires considerable space, hampering rapid correction and high resonant frequency
Solution Approach 1:
The optical element is divided into two functionally independent parts: a deformation section that engages with the deformation device, and a reference section that serves as the mounting base for sensors. This segmentation allows the reference section to remain lightweight and rigid while the deformation section handles the optical shaping, resolving the contradiction between deformation capability and unit weight.
Solution Approach 2:
The reference section is extracted as a separate functional component from the deformation section. By taking out the reference section as an independent element that does not participate in deformation, the system eliminates the need for a heavy integrated structure, enabling rapid correction and high resonant frequency while maintaining deformation accuracy.
2Measurement precision
If the measuring device is integrated with the deformation section, then the position and orientation can be monitored, but deformation causes relative movement in the measurement region leading to false corrections
Solution Approach 1:
The optical element is segmented into a deformation section and a reference section, with sensors mounted on the reference section. This segmentation ensures that measurement points remain in a stable, non-deforming region, eliminating false corrections while maintaining precise position and orientation monitoring.
Solution Approach 2:
The reference section acts as an intermediary between the deformation device and the sensors. It provides a stable reference frame that mediates the measurement process, allowing accurate detection of rigid body position and orientation changes without being affected by local deformations in the optical surface region.
3Manufacturing precision
If the resolution is increased and wavelength is decreased, then the image quality improves, but the requirements on positional accuracy and minimization of imaging errors increase
Solution Approach 1:
The patent replaces mechanical positioning systems with a sensor-based measurement and correction system. By using sensors to detect position and orientation changes and applying active deformation correction, the system achieves the high positional accuracy required for increased resolution without relying solely on mechanical precision.
Solution Approach 2:
The system implements feedback control by continuously monitoring the position and orientation of the optical element using sensors and adjusting the deformation in real-time to compensate for any deviations. This feedback mechanism enables the system to meet stringent positional accuracy requirements for high-resolution imaging.
Data Source
AI summary
An optical module, in particular for microlithography, with an optical element unit, a support device, a deformation device and a measuring device is disclosed. The support device is supported on the optical element unit, whereas for deforming an optical surface of the optical element unit, the deformation device engages a deformation section of the optical element unit comprising the optical surface. For determining the position and/or the orientation of the optical element unit with respect to an external reference in at least one degree of freedom, the measuring device comprises at least one measuring element, wherein the measuring element is arranged on a reference section of the optical element unit.