Polarization Conversion Mechanism for EUV Laser Beam Alignment
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Solution Overview
Problem
Current extreme ultraviolet (EUV) light generation systems for semiconductor photolithography face challenges in achieving precise beam alignment and adjustment, particularly at the nanoscale, leading to inefficiencies and potential degradation of optical elements due to insufficient accuracy in applying pre-pulse and pulse laser beams.
Innovation Solution
The system incorporates a polarization conversion mechanism that switches between two polarization states for guide laser beams, allowing for simultaneous detection and adjustment of both pre-pulse and pulse laser beams before their application, ensuring accurate beam alignment and reducing misalignment-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single guide laser beam is used for alignment, then the device complexity is reduced, but the beam alignment precision deteriorates
Solution Approach 1:
The guide laser system is segmented into multiple independent guide laser beams (first guide laser beam and second guide laser beam) with different polarization components. Each beam can be independently adjusted and aligned, allowing precise positioning of multiple laser beams (pre-pulse and pulse beams) without requiring a single complex alignment system. This segmentation enables separate optimization of each beam's path and polarization state.
Solution Approach 2:
The system employs dynamic polarization control through a polarization conversion mechanism that can switch between different polarization states. This allows the guide laser beams to dynamically adapt their polarization components to match the required alignment conditions for different laser beams, providing flexible and precise alignment capability while maintaining manageable system complexity.
2Manufacturing precision
If polarization conversion mechanism is added, then beam alignment precision is improved, but the device complexity increases
Solution Approach 1:
The polarization conversion mechanism serves multiple functions simultaneously: it converts polarization states of guide laser beams, enables differentiation between first and second polarization components, and facilitates precise alignment control for both pre-pulse and pulse laser beams. By consolidating these alignment and polarization control functions into a single mechanism, the system achieves high precision without proportionally increasing complexity.
Solution Approach 2:
The polarization conversion mechanism acts as an intermediary between the guide laser beams and the main laser beams. It mediates the alignment process by converting polarization states to create distinct optical paths and alignment references, enabling precise beam positioning without requiring direct mechanical adjustment of the high-power laser beams themselves.
3Manufacturing precision
If multiple laser beams with different polarizations are used, then the EUV light generation accuracy is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The system uses polarization state changes as optical signatures to differentiate between various laser beams. The first and second polarization components act as distinct optical characteristics that allow detectors to identify and measure specific beams based on their polarization state. This enables clear differentiation and accurate measurement of multiple laser beams without requiring physically separate detection 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
This approach enables high-accuracy application of EUV light generation systems, improving the precision and reliability of semiconductor microfabrication processes by ensuring accurate beam alignment and reducing optical element degradation.
Implementation Method 1
a polarization conversion mechanism located in the second optical path, and configured to be able to switch between a first state in which the third laser beam is emitted as a first guide laser beam having the first polarization component
Implementation Method 2
a dichroic mirror having a first surface located in the first optical path and a second surface located in the third optical path, and configured to reflect the first and second laser beams having the first wavelength component or the first and second guide laser beams having the second wavelength component, to transmit the first and second laser beams or the first and second guide laser beams that are not reflected by the dichroic mirror
Implementation Method 3
a polarization beam splitter located in the fourth optical path, and configured to reflect the first laser beam having the first wavelength component and having the first polarization component and the first guide laser beam having the second wavelength component and having the first polarization component, and to transmit and emit the second laser beam having the first wavelength component and having the second polarization component and the second guide laser beam having the second wavelength component and having the second polarization component
Data Source
AI summary
A laser system includes: a pulse laser system configured to emit a first laser beam having a first wavelength component and having a first polarization component and a second laser beam having the first wavelength component and having a second polarization component; a guide laser apparatus configured to emit a third laser beam having a second wavelength component; a polarization conversion mechanism configured to be able to switch between a first state in which the third laser beam is emitted as a first guide laser beam having the first polarization component, and a second state in which the third laser beam is emitted as a second guide laser beam having the second polarization component; a dichroic mirror configured to reflect the first and second laser beams having the first wavelength component or the first and second guide laser beams having the second wavelength component, to transmit the first and second laser beams or the first and second guide laser beams that are not reflected by the dichroic mirror; and a polarization beam splitter configured to reflect the first laser beam and the first guide laser beam, and to transmit the second laser beam and the second guide laser beam.