Polarization Actuator with Light-Absorbing Region for Microlithography
Solution Overview
Problem
The exact positioning of optical elements in projection exposure apparatuses for microlithography is complex and costly due to the need for precise alignment of polarizers in the beam path to alter the polarization direction of multiple light beams.
Innovation Solution
A movable optical element with a light-absorbing region is used, allowing for transverse movement and positioning control via a measuring device and drive unit, enabling simple and accurate placement of optical elements, such as polarizers, in the beam path to influence light beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarizers are positioned in the beam path to alter polarization direction, then the polarization control is achieved, but the positioning complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical positioning systems with a light-absorbing region detection method. Instead of using complex actuators and alignment mechanisms to position polarizers, the system uses a light-absorbing region that casts a shadow on a detector to directly indicate the optical element's position, substituting mechanical alignment complexity with optical detection simplicity
Solution Approach 2:
The patent introduces a light-absorbing region as an intermediary element between the optical element and the detector. This intermediary converts the position information of the optical element into a detectable shadow pattern, enabling indirect but simple measurement of optical element position without requiring direct mechanical sensing
2Adaptability or versatility
If multiple optical elements are arranged in the beam path, then the optical functionality is enhanced, but the positioning complexity increases
Solution Approach 1:
The patent merges the positioning detection function into the optical elements themselves by incorporating light-absorbing regions directly on each optical element. This allows multiple optical elements to be positioned and detected simultaneously through their respective shadows, combining the optical functionality with the positioning indication function
Solution Approach 2:
The patent adds a spatial dimension to position detection by using the shadow cast by light-absorbing regions in the beam path. Instead of measuring position directly along the optical axis, the system uses the transverse shadow pattern on the detector plane to indicate the longitudinal position of optical elements, transforming a one-dimensional positioning problem into a two-dimensional detection problem
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 approach simplifies the positioning of optical elements, reduces complexity, and allows for precise control of light beam polarization, reducing costs and improving the accuracy of structure imaging in microlithography.
Implementation Method 1
the optical element has at least one light-absorbing region which gives rise to a change in intensity in the beam path of the light beam arrangement, in particular gives rise to shading, when the optical element is moved into the beam path
Data Source
AI summary
The present invention relates to an apparatus for influencing a light beam arrangement comprising a plurality of light beams (4) arranged alongside one another, wherein provision is made of at least one optical element (5, 15, 25) which is movable transversely with respect to the light beams and by which the light beams can be influenced if the light beams pass through the optical element, and which has at least one light-absorbing region (9, 19, 29), wherein the apparatus comprises a drive device for the optical element, a measuring device for detecting the light of the light beam and a control unit, wherein the control unit is designed such that the drive device is controlled in a manner dependent on the position of the light-absorbing region. Furthermore, the present invention also relates to a projection exposure apparatus for microlithography comprising a multi-mirror array, in which the corresponding apparatus can be used, and to a method for operating the corresponding apparatus or the projection exposure apparatus.