Excimer Laser Resonator Layout for Narrow Spectral Linewidth
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Solution Overview
Problem
Chromatic aberration in semiconductor exposure apparatuses due to wide spectral linewidths of KrF and ArF excimer laser beams leads to decreased resolution, necessitating a solution to narrow the spectral linewidth to mitigate chromatic aberration.
Innovation Solution
Incorporation of a line narrowing module (LNM) with a line narrowing element, such as an etalon or grating, in the laser resonator to narrow the spectral linewidth of the laser beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a line narrowing module (LNM) including a line narrowing element (such as etalon or grating) is provided in the laser resonator to narrow the spectral linewidth, then chromatic aberration is reduced and resolution is improved, but device complexity increases
Solution Approach 1:
The patent extracts the line narrowing function from a separate module and integrates it directly into the laser resonator structure. The line narrowing element is positioned within the resonator cavity, allowing the resonator itself to perform the line narrowing function rather than requiring an external LNM, thereby reducing device complexity while maintaining resolution improvement.
Solution Approach 2:
The patent merges the line narrowing element with the laser resonator structure, combining two previously separate components (the resonator and the line narrowing module) into a single integrated system. This merging eliminates the need for separate LNM housing, alignment mechanisms, and mounting structures, thereby reducing overall device complexity while achieving the desired spectral linewidth narrowing to improve resolution.
2Object-affected harmful factors
If the spectral linewidth is narrowed using a line narrowing module, then chromatic aberration is mitigated, but the device structure becomes more complex with additional components
Solution Approach 1:
The patent extracts the line narrowing function from a separate module and integrates it directly into the laser resonator structure. The line narrowing element is positioned within the resonator cavity, allowing the resonator itself to perform the line narrowing function rather than requiring an external LNM, thereby reducing device complexity while maintaining resolution improvement.
Solution Approach 2:
The laser resonator is designed to serve multiple functions simultaneously: it provides laser oscillation and amplification while also performing spectral line narrowing through the integrated line narrowing element. This multi-functionality eliminates the need for a separate dedicated line narrowing module, thereby reducing device complexity while effectively mitigating chromatic aberration.
3Manufacturing precision
If a line narrowing element is added to the laser resonator, then the spectral linewidth is narrowed to improve resolution, but the manufacturing cost and structural complexity increase
Solution Approach 1:
The patent merges the line narrowing element with the laser resonator structure, combining two previously separate components (the resonator and the line narrowing module) into a single integrated system. This merging eliminates the need for separate LNM housing, alignment mechanisms, and mounting structures, thereby reducing overall device complexity while achieving the desired spectral linewidth narrowing to improve resolution.
Solution Approach 2:
The patent extracts the line narrowing function from a separate module and integrates it directly into the laser resonator structure. The line narrowing element is positioned within the resonator cavity, allowing the resonator itself to perform the line narrowing function rather than requiring an external LNM, thereby reducing device complexity while maintaining resolution improvement.
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 reduces chromatic aberration, enhancing the resolution of the semiconductor exposure apparatus by narrowing the spectral linewidth of the laser beam.
Implementation Method 1
an oscillation stage laser configured to generate and output a pulse laser beam
Implementation Method 2
an amplification stage laser configured to amplify the pulse laser beam output from the oscillation stage laser
Implementation Method 3
a first discharge electrode pair and a second discharge electrode pair separated from each other in a first direction intersecting an optical path of the optical resonator, the first discharge electrode pair and the second discharge electrode pair being disposed across the optical path and configured to alternately discharge
Data Source
AI summary
A laser apparatus includes an oscillation stage laser configured to generate and output a pulse laser beam, and an amplification stage laser configured to amplify the pulse laser beam output from the oscillation stage laser. The amplification stage laser includes an optical resonator configured to be a transfer optical system, a first discharge electrode pair and a second discharge electrode pair separated from each other in a first direction intersecting an optical path of the optical resonator, the first and second discharge electrode pairs being disposed across the optical path and configured to alternately discharge, and a slit disposed at a transfer position of the transfer optical system and configured to limit a beam size in a second direction orthogonal to the first direction of the pulse laser beam amplified by discharge of one of the first and second discharge electrode pairs.