EUV Light Generator Laser Beam Diameter Correction
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Solution Overview
Problem
In EUV light generating apparatuses, the instability of target droplet position during pre-pulse laser irradiation leads to uneven light intensity distribution, causing pre-plasma to jet in unintended directions and making it difficult to irradiate the diffused target with a main-pulse laser beam effectively, which affects the generation of extreme ultraviolet light.
Innovation Solution
The introduction of a correcting optical element that expands the beam diameter of the pre-pulse laser to include a region with predetermined even light intensity distribution, ensuring the droplet is irradiated uniformly, and adjusting the main-pulse laser beam diameter to accommodate the diffused target's variation, thereby stabilizing the EUV light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pre-pulse laser beam diameter is not expanded to include a region with even light intensity distribution, then the device complexity is reduced, but the target droplet position instability causes uneven light intensity distribution leading to pre-plasma jetting in unintended directions
Solution Approach 1:
A correcting optical element is introduced as an intermediary component between the pre-pulse laser source and the target droplet. This element mediates the light intensity distribution by expanding the beam diameter to include a region with even light intensity, thereby ensuring uniform irradiation on the droplet and preventing uncontrolled pre-plasma jetting.
Solution Approach 2:
The beam diameter parameter of the pre-pulse laser is changed by using a correcting optical element to expand it. This parameter change allows the laser beam to cover a region with even light intensity distribution, transforming the non-uniform irradiation into uniform irradiation on the target droplet, thus stabilizing EUV light generation.
2Reliability
If the main-pulse laser beam diameter is not adjusted to accommodate the diffused target's variation, then the device complexity is reduced, but the alignment between laser beams and diffused target deteriorates
Solution Approach 1:
The main-pulse laser beam diameter is made dynamically adjustable to accommodate variations in the diffused target position. By enabling the beam diameter to adapt to the target's diffusion extent, the system maintains effective alignment and irradiation coverage, ensuring stable EUV light generation despite target position variations.
3Illumination intensity
If a correcting optical element is introduced to expand the pre-pulse laser beam diameter, then the light intensity distribution evenness is improved, but the device complexity increases
Solution Approach 1:
The correcting optical element serves as a mediator that improves light intensity distribution evenness by expanding the pre-pulse laser beam diameter. Although this increases device complexity, it is necessary to achieve uniform irradiation on the target droplet and prevent pre-plasma jetting, thereby stabilizing EUV light generation.
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 stabilizes the energy distribution and improves the alignment of pre-pulse and main-pulse laser beams, enhancing the generation of EUV light and reducing the variation of the diffused target's position, resulting in improved optical performance and increased EUV light stability.
Implementation Method 1
a beam diameter of a pre-pulse laser beam is expanded so as to include a region in which light intensity distribution has predetermined evenness
Implementation Method 2
irradiating a target with a laser beam
Implementation Method 3
plasma generated by irradiating a target with a laser beam is used
Implementation Method 4
generates extreme ultraviolet light at a wavelength of approximately 13 nm
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3C
AI summary
A chamber device is used with at least one laser beam generating device and may include a chamber that is provided with at least one incident port for introducing at least one laser beam, which is emitted from the at least one laser beam generating device, to an inside thereof, a target supply unit that is provided to the chamber and supplies a target material to a predetermined region in the chamber, a laser focusing optical system configured to focus the at least one laser beam in the predetermined region, and an optical element configured to correct light intensity distribution of a beam section, in the predetermined region, of the at least one laser beam.