Gas Laser Unit Line Narrowing Module Spectral Width Control
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Solution Overview
Problem
Current semiconductor exposure apparatuses face challenges in achieving high resolution due to wide spectral line widths of KrF and ArF excimer laser units, leading to color aberration and reduced resolution, necessitating a solution to narrow the spectral line width of laser light outputted from gas laser units.
Innovation Solution
A discharge-excited gas laser unit with a line narrowing module, including an etalon and grating, is used to reduce the spectral line width, and a system is implemented to monitor and display energy and resource consumption, allowing for energy-saving and resource-saving modes based on operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a gas laser unit (KrF or ArF excimer laser) is used for exposure, then high power and ultraviolet output are achieved, but the spectral line width becomes wide causing color aberration and reduced resolution
Solution Approach 1:
The laser resonator is segmented into multiple sections with different gas compositions and pressures. Each section contributes to the overall laser output but with modified spectral characteristics, allowing the spectral line width to be narrowed while maintaining high power output through the combined effect of multiple segments
Solution Approach 2:
The patent changes physical parameters within the laser resonator, specifically gas pressure and gas composition ratios, to control and narrow the spectral line width. By adjusting these parameters, the laser achieves both high power output and reduced color aberration, resolving the contradiction between power and resolution
2Manufacturing precision
If the spectral line width is narrowed to reduce color aberration, then resolution is improved, but the device complexity increases due to additional line narrowing components
Solution Approach 1:
The line narrowing function is merged into the existing laser resonator structure by incorporating etalons and gratings as integral components rather than separate add-on devices. This integration achieves spectral narrowing while minimizing the increase in overall device complexity
Solution Approach 2:
The laser resonator is designed to serve multiple functions simultaneously: generating high power ultraviolet output, narrowing the spectral line width, and maintaining beam quality. The integrated design allows a single component to perform multiple roles, reducing the need for additional separate devices
3Manufacturing precision
If liquid immersion exposure is implemented with ArF excimer laser, then apparent wavelength is shortened improving resolution, but the system complexity and cost increase
Solution Approach 1:
The patent extracts the wavelength-shortening function from the external immersion system and implements it directly within the laser source itself. By generating laser light with inherently narrowed spectral width and effective shorter wavelength, the need for complex liquid immersion exposure systems is eliminated or reduced
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 effectively narrows the spectral line width, reducing color aberration and improving resolution, while also optimizing energy and resource usage by monitoring and managing consumption within the laser unit.
Implementation Method 1
A discharge-excited gas laser unit with a line narrowing module
Implementation Method 2
A line narrowing module including an etalon and a grating
Implementation Method 3
A line narrowing module including an etalon and a grating
Data Source
AI summary
There may be provided a laser unit including a display configured to display one or both of electric power consumed by the laser unit and electric energy consumed by the laser unit.