EUV Spectroscopic Polarimeter Using Magnetic Modulation
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Solution Overview
Problem
Characterizing EUV polarization is challenging due to high absorption by materials, lack of high-transmission elements like wave-plates and polarizers in the EUV and soft X-ray region, necessitating a device that can measure helicity, ellipticity, tilt angle, and degree of polarization for next-generation semiconductor manufacturing.
Innovation Solution
An EUV spectroscopic polarimeter comprising a light receiving element, two rotatable polarizing modulation elements, and an energy splitting element, which generates polarization-modulated and energy-resolved light, allowing for simultaneous measurement of polarization properties across a wide bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional polarizing elements (wave-plates, polarizers) are used in EUV region, then polarization measurement can be achieved, but transmission is extremely low due to high absorption by materials
Solution Approach 1:
The patent replaces traditional mechanical/optical polarizing elements with a magnetic field-based modulation system. A magnetic field modulates the polarization state of EUV light through magneto-optic effects in a specialized modulator, eliminating the need for physical wave-plates and polarizers that absorb EUV radiation. This substitution enables polarization measurement while maintaining high light transmission.
Solution Approach 2:
The patent changes the operating parameters by using magnetic field strength and frequency modulation instead of physical orientation changes. The magnetic field parameters (strength, frequency) are varied to modulate polarization states, allowing precise measurement without the transmission losses associated with traditional optical elements.
2Adaptability or versatility
If broadband EUV light sources are used for spectroscopic ellipsometry, then complete optical characteristics can be obtained, but polarization characterization becomes more challenging across different wavelengths
Solution Approach 1:
The patent designs a universal polarizing modulation system that operates across the entire broadband EUV spectrum. The magnetic field-based modulator and detector are wavelength-independent, allowing the same apparatus to characterize polarization states for all wavelengths in the broadband source, eliminating the need for wavelength-specific optical elements.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary that couples the broadband EUV light to the polarization detection system. The magnetic field modulator acts as a universal interface that can handle all wavelengths simultaneously, simplifying the overall system despite the broadband nature of the source.
3Measurement precision
If polarization modulation is implemented for complete EUV characterization, then measurement accuracy improves, but measuring speed decreases due to sequential measurement requirements
Solution Approach 1:
The patent implements continuous polarization modulation through time-varying magnetic fields that continuously cycle through different modulation states. The detector continuously records the modulated signal, enabling real-time polarization characterization without sequential step-by-step measurements. This continuous action maintains both high precision and fast measurement speed.
Solution Approach 2:
The patent uses periodic magnetic field modulation at specific frequencies to encode polarization information. The periodic modulation allows the detector to distinguish different polarization states through frequency analysis, enabling rapid simultaneous measurement of multiple polarization parameters without sequential scanning.
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
Enables precise characterization of EUV polarization, including helicity, ellipticity, and degree of polarization, enhancing surface characterization in the EUV and soft X-ray spectral region with increased sensitivity and measuring speed.
Implementation Method 1
the target light passes through the first polarizing modulation element so as to generate a first polarized light
Implementation Method 2
the first polarized light passes through the second polarizing modulation element so as to generate a second polarized light
Implementation Method 3
The energy splitting element receives the second polarized light so as to generate a polarization-modulated and energy-resolved light
Data Source
AI summary
We have invented an EUV spectroscopic polarimeter including a light receiving element, a first polarizing modulation element, a second polarizing modulation element, an energy splitting element and a light detecting and analyzing apparatus. The light receiving element is for receiving a target light. The first polarizing modulation element is rotatably connected to the light receiving element for generating a first polarized light. The second polarizing modulation element is rotatably connected to the first polarizing modulation element for generating a second polarized light. The energy splitting element receives the second polarized light so as to generate a modulated-polarization and energy-resolved light. The light detecting and analyzing apparatus receiving the polarization-modulated and energy-resolved light and providing a spectrum information by an analyzing algorithm which is able to retrieve the helicity, ellipticity, tilt angle and the degree of polarization for the whole spectrum of the target light.