Optical Module Facet Mirror Positioning via Selective Contact Force
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Solution Overview
Problem
In microlithography, achieving precise positioning and orientation of optical elements, especially facet mirrors, is challenging due to vibrational energy affecting the carriers, leading to misalignment and deformation, particularly in extreme UV systems with high accuracy requirements.
Innovation Solution
A selectively activatable contacting device with a contact section that exerts a contact force on optical elements to maintain precise positioning and orientation, while a vibration-damping configuration reduces the introduction of vibrations, allowing for flexible and precise adjustment of facet elements in a small space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixing forces are used to hold facet elements in position, then misalignment of facet elements can be prevented, but the carrier itself can be deformed by vibrational energy causing deflection of facet elements from desired position
Solution Approach 1:
The contacting device is divided into multiple contacting units, each with individual contact sections that can independently contact different facet elements. This segmentation allows localized stabilization without requiring high overall fixing forces that would deform the carrier.
Solution Approach 2:
The contacting device provides localized contact forces at specific facet elements rather than distributed forces across the entire carrier structure. This local quality approach stabilizes individual elements without subjecting the carrier to high global forces that would cause deformation.
2Adaptability or versatility
If active influencing of position and orientation of optical elements is implemented, then flexibility of the optical system is increased, but the complexity of the system increases
Solution Approach 1:
The contacting device can be selectively activated and deactivated, transitioning between static and dynamic states. During operation, it provides active stabilization when needed and remains inactive when not required, enabling flexibility without permanent complexity.
Solution Approach 2:
The positioning device and contacting device work together where the positioning device actively adjusts facet element positions and the contacting device passively maintains these positions through contact forces, creating a self-stabilizing system that reduces overall complexity.
3Adaptability or versatility
If a large number of facet elements are used for pupil formation, then flexibility for pupil formation is improved, but the difficulty of realizing precise setting and holding of each facet element increases
Solution Approach 1:
The contacting device is segmented into multiple contacting units, each capable of independently contacting and stabilizing individual facet elements. This allows precise positioning of each element without requiring complex centralized control mechanisms.
Solution Approach 2:
The invention replaces complex mechanical linkage systems with simple contact forces between the contacting device and facet elements. This substitution maintains positioning precision while significantly reducing mechanical complexity for systems with large numbers of elements.
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
The solution ensures reliable and precise positioning and orientation of optical elements, reducing the impact of vibrations and eliminating the need for complex closed-loop control systems, thereby enhancing imaging quality and stability in microlithography.
Implementation Method 1
a selectively activatable contacting device having at least one contacting unit having a first contact section, the first contact section, in an activated state of the contacting device, contacting a second contact section of the optical element in order to exert a contact force on the optical element
Implementation Method 2
it is likewise also possible, via a correspondingly vibration-damping configuration of at least one damping section (located in the region of the optical element and/or of the contacting device), to achieve a targeted damping of vibrations that were introduced into the optical element
Data Source
AI summary
The present invention relates to an optical module, in particular facet mirror, comprising an optical element and a supporting structure for supporting the optical element, wherein the supporting structure comprises a positioning device for actively setting a position and/or orientation of the optical element in at least one degree of freedom. The supporting structure comprises a selectively activatable contacting device having at least one contacting unit having a first contact section, wherein the first contact section, in an activated state of the contacting device, contacts a second contact section of the optical element in order to exert a contact force on the optical element, while the first contact section, in a deactivated state of the contacting device is removed from the second contact section.