Polarization System Using Oxide Fluoride Layers
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Solution Overview
Problem
Existing polarization systems for UV ranges suffer from high energy losses due to transmission of polarized components, making them inefficient for use in deep UV photolithography.
Innovation Solution
A polarization system utilizing alternating sequences of high and low refractive index oxide and fluoride layers on substrates, where the beam is incident at angles greater than the Brewster angle, preferentially reflecting and polarizing the beam with minimal transmission loss, and using quartz glass and calcium fluoride substrates to minimize costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the transmitted and polarized component is used, then the beam can be transmitted through the substrate, but the transmission suffers from high losses at short wavelengths
Solution Approach 1:
Instead of using the transmitted polarized component as conventionally done, the invention inverts the approach by utilizing the reflected polarized component. The layer system is designed to reflect the polarized beam with high efficiency, converting the previously harmful reflection into the useful transmitted beam, thereby avoiding the high transmission losses at short wavelengths
Solution Approach 2:
The invention changes the operational parameters by adjusting the angle of incidence to be greater than the Brewster angle. This parameter change enables the layer system to achieve high reflectivity for the polarized component while maintaining low losses, fundamentally altering how the system handles the polarized light
2Reliability
If cemented systems with crystals of different orientations are used, then polarization can be achieved, but the system cannot be used in the UV range due to damage from short-wave radiation
Solution Approach 1:
The invention replaces expensive, UV-sensitive crystal materials with more robust substrate materials that can withstand UV radiation. The layer system is designed to achieve the polarization function without relying on UV-vulnerable cemented crystal structures, effectively creating a UV-resistant alternative
Solution Approach 2:
The invention uses composite structures combining substrate materials with specifically designed layer systems. This composite approach allows the system to achieve polarization functionality while using materials that are resistant to UV radiation damage, unlike the conventional crystal-based systems
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
Achieves a high proportion of reflected and polarized radiation with minimal energy loss, suitable for wavelengths below 250 nm, enhancing the polarization efficiency and reducing costs in high-energy applications.
Implementation Method 1
at least one second component reflected by the layer system and largely polarized
Implementation Method 2
the first stack comprises an alternating sequence of high- and low-refractive-index oxide layers, wherein the second stack comprises an alternating sequence of high- and low-refractive-index fluoride layers
Implementation Method 3
which is irradiated at an angle Φ that is greater than the Brewster angle for the substrate material used
Implementation Method 4
converts initially unpolarized radiation into polarized radiation, wherein the energy density is approximately maintained as it passes through the polarization system
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to a polarization system (1) comprising the following features: - a first substrate (3) composed of a first substrate material with a first layer system (3a) applied thereto, and, disposed downstream in a beam path (2) formed by a beam source, at least one second substrate (4) composed of a second substrate material with a second layer system (4a) applied thereto; - wherein the first and second layer systems comprise a first stack (3b, 4b) applied on the substrate and a second stack (3c, 4c) applied on the first stack; - wherein the first stack comprises an alternating sequence of high and low refractive index oxidic layers; - wherein the second stack comprises an alternating sequence of high and low refractive index fluoridic layers; - wherein the first layer system (3a) splits an unpolarized beam (2a), which forms the beam path (2) and impinges on the layer system (3a) at an angle Φ that is greater than the Brewster angle for the substrate material used, into a first component (2d), which is for the most part polarized and is transmitted through the substrate, and at least one second component (2e), which is for the most part polarized and is reflected at the layer system (3a); - wherein the first layer system (3a) is designed in terms of its number of oxidic and fluoridic layers in such a way that the proportion of the reflected and polarized second component (2e) is at least 90%; - wherein the second layer system (4a) splits a beam, which forms the beam path, has a proportion of the for the most part polarized second component (2e) of at least 90% and impinges on the layer system, into a first component (2d), which is for the most part polarized and is transmitted through the substrate, and at least one second component (2e), which is for the most part polarized and is reflected at the layer system (4a), wherein the proportion of the for the most part polarized second component is greater downstream of the second layer system than downstream of the first layer system.