Gas Laser Amplifier Resonator Layout for Narrower Spectral Line Width
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Solution Overview
Problem
Chromatic aberration in gas laser devices used for semiconductor exposure due to large spectral line widths, leading to reduced resolution in semiconductor integrated circuits.
Innovation Solution
A gas laser device with a laser oscillator and amplifier, featuring an input and output coupling optical system where the focal points coincide, and a confocal resonator configuration to maintain alignment and reduce spectral line width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a line narrowing module (LNM) including a line narrowing element (etalon, grating, and the like) is provided in a laser resonator to narrow a spectral line width, then chromatic aberration is reduced, but device complexity increases
Solution Approach 1:
The patent extracts the line narrowing function from a separate module (etalon, grating) and integrates it into the resonator mirrors themselves. The resonator mirrors are designed with specific reflective characteristics that inherently narrow the spectral line width without requiring additional line narrowing elements, thus reducing device complexity while maintaining spectral precision.
Solution Approach 2:
The resonator mirrors serve multiple functions: they provide optical feedback for laser oscillation and simultaneously perform spectral line narrowing through their designed reflective characteristics. This multi-functionality eliminates the need for separate line narrowing modules, resolving the contradiction between spectral precision and device complexity.
2Stability of the object's composition
If the focal points of the input and output coupling optical systems coincide, then beam profile stability is improved, but alignment difficulty increases
Solution Approach 1:
The patent employs asymmetric optical path designs where the input and output coupling optical systems have different configurations but are engineered to converge at a common focal point. This asymmetric yet coordinated design achieves beam profile stability while managing alignment complexity through careful optical path engineering.
Solution Approach 2:
The patent replaces complex mechanical alignment mechanisms with optical design solutions. By using specific optical element arrangements and focal point convergence, the system achieves stable beam profiles without relying on complex mechanical adjustment mechanisms, thereby improving ease of operation while maintaining stability.
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
Enhances amplification efficiency and maintains beam profile stability, reducing chromatic aberration and improving resolution in semiconductor manufacturing.
Implementation Method 1
a discharge chamber accommodating a pair of electrodes for causing discharge
Implementation Method 2
an input coupling optical system configured to cause at least a part of the laser light to be transmitted toward the discharge chamber
Implementation Method 3
an output coupling optical system configuring an optical resonator together with the input coupling optical system
Data Source
AI summary
A gas laser device includes a laser oscillator outputting laser light, and a laser amplifier amplifying the laser light and outputting the amplified laser light. The laser amplifier includes a discharge chamber accommodating electrodes for causing discharge, an input coupling optical system causing part of the laser light to be transmitted toward the discharge chamber, and an output coupling optical system configuring an optical resonator together with the input coupling optical system and causing part of the laser light transmitted through the input coupling optical system and the discharge chamber to be transmitted therethrough and output the amplified laser light. A first focal point of the input coupling optical system and a second focal point of the output coupling optical system in a first direction being perpendicular to a direction of the discharge coincides at a position between the input coupling optical system and the output coupling optical system.