Optical Surface Tilt Measurement via Waveguide Beam
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Solution Overview
Problem
Current methods for determining the actual tilt of optical surfaces in lithography systems are inadequate for increasing precision, as they fail to provide precise and reliable measurements, leading to inaccuracies in aligning wavefronts and affecting the quality of light or radiation guided by these surfaces.
Innovation Solution
An optical apparatus with a measuring device that uses a waveguide to form a closed measurement section, where a measurement beam propagates and is influenced by the tilt of the optical surface, allowing for precise sensing of the tilt through changes in the measurement beam, and a method that employs actuators to influence the tilt of the optical surface, enabling accurate determination of the actual tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used to determine the actual tilt of optical surfaces, then the device complexity is low, but the measurement precision is inadequate for increasing precision requirements
Solution Approach 1:
A waveguide is introduced as an intermediary component to guide a measurement beam along a closed measurement section adjacent to the optical surface. The waveguide enables precise optical measurement of surface tilt by mediating between the measurement beam and the optical surface, allowing accurate detection of surface geometry changes without direct contact.
Solution Approach 2:
The patent replaces conventional mechanical or contact-based measurement methods with an optical measurement system. A measurement beam propagates through a waveguide to optically detect the actual tilt of the optical surface, substituting mechanical measurement approaches with non-contact optical field-based measurement to achieve higher precision.
2Reliability
If the measurement beam is exposed to the external environment, then the device complexity is low, but the measurement reliability is reduced due to susceptibility to external disturbances
Solution Approach 1:
The waveguide acts as a protective enclosure (similar to a flexible shell) that confines the measurement beam within a closed measurement section. This protects the optical measurement path from external environmental disturbances such as dust, air currents, and vibrations, thereby improving measurement reliability while maintaining a relatively simple integrated structure.
Solution Approach 2:
The closed measurement section formed by the waveguide creates a controlled, isolated environment for the measurement beam, analogous to an inert atmosphere. This enclosed optical path shields the measurement process from harmful external factors, ensuring stable and reliable measurements without requiring complex external shielding structures.
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
This solution allows for precise and reliable measurement of the optical surface tilt, improving the alignment of wavefronts and enhancing the control of light or radiation, thereby increasing the precision and stability of the lithography system.
Implementation Method 1
The measuring device comprises at least one waveguide which forms a closed measurement section, with the waveguide being configured to input couple and allow propagation of one or more modes of a measurement beam
Implementation Method 2
a tilt of the optical surface influences the measurement beam propagating through the waveguide, with the measuring device being configured to sense an influence on the measurement beam caused by the tilt of the optical surface
Data Source
AI summary
An optical device, such as for a lithography system, comprises: at least one optical element having at least one optical surface; one or more actuators to tilt the optical surface of the optical element; and a measuring device to detect a tilt of the optical surface from an idle position. The measuring device has at least one waveguide which forms a closed measuring section. The waveguide is designed for coupling in and propagating one or more modes of a measuring beam. The waveguide is arranged such that a tilt of the optical surface influences the measuring beam propagating through the waveguide. The measuring device is designed to detect an influencing of the measuring beam caused by the tilt of the optical surface.