Excimer Laser Chamber Return Member for Stable Gas Flow
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Solution Overview
Problem
Chromatic aberrations in projection lenses due to wide spectral linewidth of laser light from KrF and ArF excimer laser apparatuses, leading to decreased resolution in semiconductor exposure apparatuses, necessitate a narrowed spectral linewidth to maintain resolution.
Innovation Solution
A chamber apparatus for a laser with a return member having a ladder section and a plate-shaped section that guides laser gas flow perpendicular to the optical axis, ensuring stable discharge and output of laser light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser gas flow is not properly guided between discharge electrodes, then simple chamber structure is maintained, but stagnation and vortices occur in the laser gas flow leading to unstable discharge and laser light output
Solution Approach 1:
The return member is divided into multiple functional sections: a ladder section with multiple linear portions arranged in parallel to guide gas flow, and a plate-shaped section inclined relative to the optical axis to redirect flow. This segmentation allows each portion to perform a specific flow control function, preventing stagnation and vortices while maintaining overall structural coherence.
Solution Approach 2:
The return member acts as an intermediary component between the discharge electrodes and the chamber body, electrically connecting the second discharge electrode to the chamber body while simultaneously guiding the laser gas flow. This intermediary structure resolves the contradiction by providing both electrical connectivity and flow control functions in a single integrated component.
2Manufacturing precision
If spectral linewidth is not narrowed, then simple laser resonator structure is maintained, but chromatic aberrations occur in projection lenses leading to decreased resolution
Solution Approach 1:
The line narrowing element (etalon or grating) is positioned within the laser resonator to pre-narrow the spectral linewidth of the laser light before it exits the resonator and enters the projection lens system. This preliminary action of spectral narrowing prevents chromatic aberrations downstream, maintaining high resolution in semiconductor exposure applications.
3Reliability
If discharge electrode configuration is simplified, then ease of manufacture is improved, but stable discharge cannot be maintained due to improper gas flow between electrodes
Solution Approach 1:
The return member performs multiple functions simultaneously: it provides electrical connection between the second discharge electrode and the chamber body, guides the laser gas flow perpendicular to the optical axis, and prevents the formation of stagnation zones and vortices. This multi-functionality maintains stable discharge without requiring separate components for each function, thereby preserving ease of manufacture.
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
Stabilizes laser light output by preventing stagnation and vortices in the laser gas flow, enhancing the stability and resolution of the laser light emitted.
Implementation Method 1
The fan is configured to cause the laser gas to flow between the first discharge electrode and the second discharge electrode in a direction perpendicular to an optical axis of the laser light
Implementation Method 2
A chamber apparatus for a laser is configured to output laser light by exciting a laser gas with an aid of discharge
Data Source
AI summary
A chamber apparatus for a laser includes a chamber, first and second discharge electrodes, a fan, and a return member. The chamber includes a chamber body and an insulating plate. The chamber has an internal space filled with a laser gas. The first and second discharge electrodes are disposed in the internal space. The fan causes the laser gas to flow between the first and second discharge electrodes. The return member is provided upstream of the second discharge electrode in a flow of the laser gas. The return member includes a ladder section and a plate-shaped section. The ladder section includes multiple linear portions. The plate-shaped section is connected to the multiple linear portions. The plate-shaped section is inclined such that the further the return member is away from the top wall, the more downstream the return member is in the flow of the laser gas.