EUV Condensation Mirror Stepped Reflection Segmentation
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Solution Overview
Problem
Current extreme ultraviolet light condensation mirrors face degradation issues due to the adhesion of fine particles and plasma-generated ions, leading to uneven irradiation intensity and reduced lifetime, particularly on the center side of the reflective surface.
Innovation Solution
The design incorporates a reflective surface with specific stepped portions and reflection portions arranged in a concentric pattern, where the height of the first stepped portion is higher than the second, optimizing the diffraction of laser beams and reducing the irradiation intensity and ion density on the center side, thereby minimizing degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reflective surface is positioned closer to the plasma generation region to improve EUV light collection efficiency, then the EUV light output increases, but the irradiation intensity and ion density on the center side increase causing accelerated degradation
Solution Approach 1:
The reflective surface is divided into multiple reflection portions (first reflection portions and second reflection portions) with different heights and functions. The first reflection portions are positioned higher and have different diffraction characteristics compared to the second reflection portions, allowing differential control of laser beam paths to reduce ion density on the center side while maintaining EUV collection efficiency.
Solution Approach 2:
Different regions of the reflective surface are given different properties: the first reflection portions have specific heights and diffraction characteristics optimized for reducing ion density, while the second reflection portions are optimized for EUV light reflection. This local differentiation allows the center side to be protected from degradation while maintaining overall system performance.
2Productivity
If the reflective surface is positioned closer to the plasma generation region to improve EUV light collection efficiency, then the EUV light output increases, but the irradiation intensity on the center side increases causing uneven intensity distribution
Solution Approach 1:
The reflective surface is segmented into first and second reflection portions with different heights and diffraction properties. This segmentation enables independent optimization of light paths from different regions, allowing the system to achieve both high EUV output and uniform intensity distribution by controlling how laser beams from different areas are diffracted and reflected.
Solution Approach 2:
The height parameter of different reflection portions is specifically controlled to change the diffraction behavior of laser beams. By adjusting the height of first and second reflection portions, the system modifies the optical path lengths and phase relationships, resulting in more uniform EUV light intensity distribution across the output beam.
3Productivity
If the reflective surface is positioned closer to the plasma generation region to improve EUV light collection efficiency, then the EUV light output increases, but the ion density on the center side increases causing accelerated degradation
Solution Approach 1:
The reflective surface is divided into first reflection portions positioned at different heights than second reflection portions. The first reflection portions are specifically designed to diffract laser beams in a manner that reduces ion density accumulation on the center side of the reflective surface, while still maintaining proximity to the plasma generation region for efficient EUV collection.
Solution Approach 2:
The diffraction grating structure, which initially might seem to complicate the optical system, is used to convert the harmful concentrated ion density into a beneficial distribution pattern. By carefully designing the periodic structure of reflection portions, the system uses diffraction to spread out and reduce ion density on the center side while maintaining high EUV light collection efficiency.
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 separation of the reflective surface from the plasma generation region, reducing the irradiation intensity and ion density on the center side, leading to improved durability and consistent EUV light distribution.
Implementation Method 1
a reflective surface formed in a concave shape and configured to reflect extreme ultraviolet light incident from a first focal point so that the extreme ultraviolet light condenses to a second focal point
Implementation Method 2
diffract a laser beam incident from the first focal point and having a wavelength longer than a wavelength of the extreme ultraviolet light
Data Source
AI summary
An extreme ultraviolet light condensation mirror may include a reflective surface formed in a concave shape and configured to diffract a laser beam incident from a first focal point and having a wavelength longer than a wavelength of extreme ultraviolet light. The reflective surface may be provided with a plurality of first reflection portions, a plurality of second reflection portions, a plurality of first stepped portions, and a plurality of second stepped portions. The first and second stepped portions may have such heights that the laser beam obtains phases opposite to each other through reflection at the first and second reflection portions adjacent to each other. The height of each first stepped portion may be equal to or higher than the height of each second stepped portion. The height of at least one of the first stepped portions may be higher than the height of each second stepped portion.