Beam Splitting Apparatus with Reflective Diffraction Gratings
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Solution Overview
Problem
Lithographic systems using beam splitting apparatuses face instability in power and pointing direction of output radiation beams due to variations in wavelength and pointing direction of input radiation, particularly when using free electron lasers, which affects the precision of pattern formation on substrates.
Innovation Solution
A beam-splitting apparatus comprising multiple reflective diffraction gratings that split input radiation into output beams with only one instance of a non-zeroth diffraction order in each optical path, stabilizing power and pointing direction by configuring each output beam to include only a 0th diffraction order, and using actuators to control grazing incidence and azimuthal angles for dynamic power adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple diffraction gratings are used to split the radiation beam, then the beam can be distributed to multiple lithographic apparatus, but the power and pointing direction of output beams become unstable due to wavelength and pointing direction variations of input radiation
Solution Approach 1:
The system segments the radiation beam into multiple separate beams using multiple diffraction gratings, with each grating directing a specific diffraction order to a different lithographic apparatus. This allows simultaneous distribution of the beam to multiple apparatus while maintaining independent control over each output beam's characteristics
Solution Approach 2:
The system exploits the relationship between diffraction order, wavelength, and diffraction angle by assigning different diffraction orders to different apparatus. By carefully selecting which diffraction orders to use and how to configure the gratings, the system compensates for input variations and stabilizes the output beam parameters despite wavelength and pointing direction fluctuations
2Adaptability or versatility
If diffraction gratings are configured to form multiple diffraction orders, then beam splitting capability is enhanced, but control complexity increases due to need to manage multiple beams
Solution Approach 1:
The system extracts and utilizes only the necessary diffraction orders for beam splitting, rather than attempting to control all possible diffraction orders. By selecting specific orders (e.g., +1, -1, +2, -2) and directing them to appropriate apparatus, the system achieves effective beam splitting while simplifying the control architecture
Solution Approach 2:
Each diffraction grating serves multiple functions: it diffracts the incoming beam into multiple orders, separates spatial frequencies, and directs different orders to different lithographic apparatus. This multi-functionality reduces the need for separate components for each function, thereby managing complexity
3Ease of manufacture
If the beam splitting apparatus uses conventional optical elements, then the system design is simpler, but manufacturing precision of patterns on substrates is reduced due to power and pointing direction instability
Solution Approach 1:
The system replaces conventional mechanical beam steering and power control mechanisms with a diffraction-based optical system. By using the inherent properties of diffraction gratings to control beam direction and distribution, the system achieves precise pattern formation without complex mechanical adjustment mechanisms, thereby maintaining ease of manufacture while improving precision
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 configuration enhances the stability of output radiation beams' power and pointing direction, ensuring consistent and precise pattern formation on substrates despite variations in input radiation, improving the overall performance of lithographic systems.
Implementation Method 1
comprising a plurality of reflective diffraction gratings arranged to receive a radiation beam and configured to form a diffraction pattern comprising a plurality of diffraction orders
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~5B
AI summary
A beam-splitting apparatus arranged to receive an input radiation beam and split the input radiation beam into a plurality of output radiation beams. The beam-splitting apparatus comprising a plurality of reflective diffraction gratings arranged to receive a radiation beam and configured to form a diffraction pattern comprising a plurality of diffraction orders, at least some of the reflective diffraction gratings being arranged to receive a 0th diffraction order formed at another of the reflective diffraction gratings. The reflective diffraction gratings are arranged such that the optical path of each output radiation beam includes no more than one instance of a diffraction order which is not a 0th diffraction order.