EUV Laser Beam Guidance Device for Multi-Focus Control
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Solution Overview
Problem
Existing EUV excitation light sources face challenges in generating multiple foci of a laser beam at different locations, which affects the efficient irradiation and EUV radiation emission from target materials.
Innovation Solution
A beam guidance device is used to divide and manipulate a laser beam into separate beams, allowing for the generation of multiple foci at predetermined locations in three-dimensional space, enabling the pre-pulse and main-pulse to be focused at distinct positions for optimal target material irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple lasers with different wavelengths are used to generate pre-pulse and main-pulse, then the EUV radiation generation efficiency is improved, but the laser beams with different wavelengths are focused at different distances due to chromatic aberrations, making it difficult to focus both pulses at the same target location
Solution Approach 1:
The patent divides the laser beam into multiple separate beams using a beam splitter, allowing each beam to be manipulated independently through different optical paths. This enables separate control of the pre-pulse and main-pulse focusing positions, resolving the chromatic aberration issue while maintaining the use of multiple lasers for efficient EUV generation.
Solution Approach 2:
The patent uses a curved mirror to focus the separate beams, creating foci at different three-dimensional locations rather than along a single linear optical axis. This spatial separation in 3D space allows independent optimization of focus positions for different wavelength beams, eliminating the constraint of chromatic aberrations on a single axis.
2Device complexity
If a single laser beam is used for both pre-pulse and main-pulse, then the device complexity is reduced, but it is not possible to generate multiple foci at different locations for optimal target material irradiation
Solution Approach 1:
The beam guidance device segments a single laser beam into multiple separate beams using beam splitters. This allows the system to maintain a simple single-laser configuration while achieving the functional equivalence of multiple lasers by creating independent optical paths that can be focused at different locations.
Solution Approach 2:
The patent introduces a beam guidance device as an intermediary between the single laser source and the target material. This intermediary system includes beam splitters and curved mirrors that manipulate the beam paths, enabling multiple focus locations to be generated from a single laser beam without requiring multiple laser sources.
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 allows for precise control of the pre-pulse and main-pulse to effectively deform, heat, and expand target material droplets, enhancing EUV radiation generation and emission efficiency.
Implementation Method 1
a beam guidance device (22) for manipulating a laser beam (10), in particular for manipulating at least one separate beam of the laser beam
Implementation Method 2
with the aid of a curved mirror (5), the separate beams of the laser beam are focused at different distances at a predetermined location
Implementation Method 3
Devices for generating EUV (Extreme UltraViolet) radiation are known which excite a target material containing, for example, xenon, lithium or tin with a laser beam
Implementation Method 4
The target material prepared by the 'pre-pulse' is then converted into plasma by a so-called main pulse and emits EUV light
Implementation Method 5
a focus or focal point can be set for a 'pre-pulse' that differs from a focus of a 'main-pulse'. Thus, a target material can be optimally irradiated to place a droplet of target material, prepared by the 'pre-pulse'
Data Source
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AI summary
An EUV excitation light source (1) with a beam guiding device (22) for manipulating at least one laser beam (10, 12) is provided. The beam guiding device (22) has at least one beam splitter (2) for generating at least two separated beams (10', 11, 12', 13) from the at least one laser beam (10, 12), at least one mirror (4, 5, 15, 16, 17, 18) or a lens for manipulating at least one of the separated beams (10', 11, 12', 13), a superimposition mirror (3) for superimposing the at least two separated beams (10'', 11''', 12'', 13'''), and a focusing device (6) for generating a respective focus (7, 8) of the at least two separated beams (10'', 11''', 12'', 13'''). At least two focuses (7, 8) at an identical position or at two different positions can be formed by the beam guiding device (22).