Solid-State Laser Wavelength Control for Exposure Resolution
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Solution Overview
Problem
Current semiconductor exposure apparatuses face challenges in achieving narrow spectral line widths for pulsed laser light, leading to color aberration and reduced resolution due to wide spectral line widths of KrF and ArF excimer laser units, necessitating the development of a system that can efficiently narrow and control the wavelength of laser light for improved resolution.
Innovation Solution
A solid-state laser system comprising a first and second solid-state laser unit, a wavelength conversion system, a wavelength detector, and a wavelength controller, which generates and controls pulsed laser light beams to achieve a target wavelength by varying the wavelengths of the first and second laser units based on detected differences, ensuring the spectral line width is minimized and color aberration is mitigated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If gas laser units (KrF or ArF excimer laser) are used for exposure, then ultraviolet light can be outputted, but the spectral line width becomes wide causing color aberration and reduced resolution
Solution Approach 1:
The system divides the laser generation into multiple independent solid-state laser units (first and second laser units), each contributing to the final ultraviolet output through wavelength conversion. This segmentation allows precise control of each unit's parameters to achieve narrow spectral width while maintaining UV output capability.
Solution Approach 2:
The invention changes the fundamental operating parameters by using solid-state laser media instead of gas laser media, enabling narrow spectral line width operation. The wavelength conversion process further adjusts parameters to achieve the target ultraviolet wavelength with minimal spectral broadening.
2Manufacturing precision
If spectral line width is narrowed to reduce color aberration, then resolution improves, but system complexity increases due to additional wavelength control mechanisms
Solution Approach 1:
The system incorporates a wavelength detector that continuously monitors the output wavelength and provides feedback to the wavelength controller. This closed-loop feedback mechanism automatically adjusts the laser units to maintain narrow spectral width and correct wavelength, simplifying operation while ensuring high resolution performance.
Solution Approach 2:
The wavelength controller performs multiple functions: it controls both the first and second solid-state laser units, manages the wavelength conversion process, and responds to detector feedback. This multi-functionality reduces the need for separate control systems for each component.
3Manufacturing precision
If solid-state laser units with wavelength conversion are used, then spectral line width is narrowed, but the device structure becomes more complex
Solution Approach 1:
The invention merges the wavelength conversion function into the integrated laser apparatus structure, combining the first and second solid-state laser units with the wavelength conversion mechanism in a unified system. This integration reduces overall complexity compared to separate laser and wavelength conversion systems.
Solution Approach 2:
The wavelength conversion system acts as an intermediary between the solid-state laser units and the final ultraviolet output. It mediates the wavelength adjustment process, enabling precise spectral control while isolating the complexity of wavelength management from the laser generation process.
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 system effectively narrows the spectral line width of pulsed laser light, reducing color aberration and enhancing the resolution of the semiconductor exposure apparatus by precisely controlling the wavelength of the laser light, thereby improving the accuracy and efficiency of the exposure process.
Implementation Method 1
The wavelength conversion system is configured to receive the first pulsed laser light beam and the second pulsed laser light beam, and output a third pulsed laser light beam with a third wavelength that is converted from the first wavelength and the second wavelength
Data Source
AI summary
A solid-state laser system may include a first solid-state laser unit, a second solid-state laser unit, a wavelength conversion system, a wavelength detector, and a wavelength controller. The wavelength conversion system may receive a first pulsed laser light beam with a first wavelength and a second pulsed laser light beam with a second wavelength, and output a third pulsed laser light beam with a third wavelength converted from the first and second wavelengths. The wavelength controller may control the first solid-state laser unit to vary the first wavelength on a condition that an absolute value of a difference between a value of a target wavelength and a value of the third wavelength detected by the wavelength detector is equal to or less than a predetermined value, and control the second solid-state laser unit to vary the second wavelength on a condition that the absolute value exceeds the predetermined value.