Profiled Coating Layer Wedged Elements EUV Mirror
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Solution Overview
Problem
Current lithographic apparatuses face challenges in manufacturing multi-layer mirrors with high accuracy, leading to increased costs and potential contamination issues that degrade EUV beam quality due to the need for precise protrusions to block undesired radiation frequencies.
Innovation Solution
A mirror with a profiled coating layer featuring wedged elements having a wedge angle of approximately 10-200 mrad, which effectively deflects unwanted radiation frequencies while allowing EUV radiation to pass through, thereby improving beam quality and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If protrusions are individually manufactured with high accuracy to form diffraction patterns, then undesired radiation frequencies are blocked, but manufacturing costs increase
Solution Approach 1:
The mirror surface is segmented into multiple zones, each zone containing protrusions that form diffraction patterns. This segmentation allows each zone to be optimized independently for blocking specific unwanted frequencies while maintaining overall system performance, reducing the need for high-precision individual protrusion manufacturing across the entire mirror surface.
Solution Approach 2:
Different zones of the mirror are assigned different protrusion patterns and properties tailored to their specific function of blocking particular frequency ranges. This local optimization allows each region to effectively block its target frequencies without requiring uniform high-precision manufacturing across all areas, thereby reducing overall manufacturing costs.
2Manufacturing precision
If protrusions are provided with high accuracy, then diffraction patterns are formed correctly, but manufacturing complexity increases
Solution Approach 1:
The mirror is divided into multiple zones with protrusions that can be manufactured using standardized processes. Each zone's protrusions are designed to work collectively to form the required diffraction pattern, reducing the precision requirement for individual protrusions while maintaining overall pattern accuracy.
Solution Approach 2:
Standardized protrusion patterns are replicated across multiple zones of the mirror. This copying approach allows for simpler manufacturing processes where proven patterns can be reproduced across different areas, reducing the need for complex custom manufacturing while maintaining consistent performance.
3Ease of manufacture
If areas between protrusions are left uncovered, then manufacturing is simplified, but contaminants may accumulate and decrease reflectivity
Solution Approach 1:
A thin protective coating layer is applied over the entire mirror surface, including the areas between protrusions. This thin film acts as a barrier to contaminant accumulation while being thin enough to allow the underlying protrusion diffraction patterns to function effectively, thus protecting beam quality without significantly complicating manufacturing.
Solution Approach 2:
The mirror structure combines the base mirror material with a protective coating layer, creating a composite structure. The base material provides the diffraction functionality through protrusions, while the coating layer provides contamination resistance, achieving both manufacturing simplicity and reliable beam quality.
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
The solution enhances EUV beam quality by suppressing undesired radiation frequencies by up to 100 times, reducing contamination risks, and simplifying the manufacturing process, thus improving the overall performance and efficiency of the lithographic apparatus.
Implementation Method 1
the undesired further radiation is substantially blocked due to absorption, refraction or deflection of this further radiation when impinged on the protrusions
Implementation Method 2
the undesired further radiation is substantially blocked due to absorption, refraction or deflection of this further radiation when impinged on the protrusions
Implementation Method 3
the multilayer mirrors of the illumination and projection systems are optimized for reflection of the desired wavelength, e.g. about 6.7 nm or about 13.5 nm
Implementation Method 4
the undesired further radiation is substantially blocked due to absorption, refraction or deflection of this further radiation when impinged on the protrusions
Data Source
AI summary
Embodiments of the invention relate to a mirror (30). The mirror includes a mirroring surface and a profiled coating layer (32a) having an outer surface, wherein one or more wedged elements are formed by the outer surface with respect to the mirroring surface, and wherein the one or more wedged elements having a wedge angle (ø) in a range of approximately 10-200 mrad. The profiled coating layer may have a curved outer surface. The profiled coating layer may be formed from at least one of the following materials: Be, B, C, P, K, Ca, Sc, Br, Rb, Sr, Y, Zr, Ru, Nb, Mo, Ba, La, Ce, Pr, Pa and U.