Excimer Laser Gas Management for Stable Pulsed Output
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Solution Overview
Problem
Excimer laser apparatuses face challenges in maintaining stable output over long periods due to impurity buildup in the laser chamber, which can lead to a worsening discharge state and inability to produce desired pulsed laser light, necessitating frequent complete gas replacement, disrupting exposure device operations.
Innovation Solution
The implementation of gas pressure control, halogen gas filling control, and partial gas replacement control within the laser chamber during laser oscillation to suppress environmental degradation and reduce the need for complete gas replacement, using a system with a laser chamber, electrodes, a power source, gas supply and exhaust units, and a control unit to selectively manage gas concentrations and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complete gas replacement is performed frequently to maintain laser output quality, then laser output stability is improved, but device operation continuity deteriorates due to operational disruptions
Solution Approach 1:
The gas supply unit performs preliminary action by continuously or periodically supplying fresh laser gas to the laser chamber before impurity buildup reaches critical levels. This proactive gas replenishment prevents degradation of the laser medium, maintaining output stability without requiring complete gas replacement and operational interruptions.
Solution Approach 2:
The system implements continuity of useful action by maintaining continuous laser operation through automated gas management. The gas supply and exhaust units work continuously or periodically to refresh the laser gas, eliminating the need to stop operations for gas replacement, thus ensuring uninterrupted productive operation.
2Productivity
If complete gas replacement is avoided to maintain operation continuity, then device operation continuity is improved, but laser output stability deteriorates due to impurity buildup
Solution Approach 1:
Instead of complete gas replacement, the system applies partial action by supplying fresh laser gas in controlled amounts that are sufficient to maintain output stability but do not require full chamber depressurization and recharging. This partial gas replenishment approach maintains both operational continuity and laser performance.
Solution Approach 2:
The gas control system implements self-service by automatically monitoring and managing laser gas quality through the gas supply and exhaust units. The system autonomously performs gas refreshment operations to maintain laser output stability without requiring external intervention or operational shutdowns, effectively servicing itself to preserve both continuity and stability.
3Reliability
If gas pressure control is implemented to suppress chamber degradation, then chamber degradation is reduced, but gas management complexity increases
Solution Approach 1:
The gas control unit implements parameter changes by dynamically adjusting gas supply rates, exhaust rates, and pressure levels to optimize laser chamber conditions. By controlling parameters such as gas flow rates and partial pressures of laser gas components, the system suppresses chamber degradation and maintains laser performance through precise parameter management.
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
This approach effectively suppresses chamber degradation, reduces the frequency of complete gas replacements, and maintains stable pulsed laser output, ensuring continuous operation of exposure devices by selectively managing gas pressures and concentrations within the laser chamber.
Implementation Method 1
gas pressure control in which the gas supply unit supplies the second laser gas to the interior of the laser chamber or the gas exhaust unit partially exhausts gas from within the laser chamber
Implementation Method 2
at least a pair of electrodes disposed within the laser chamber; a power source unit that supplies a voltage between the electrodes
Implementation Method 3
a KrF excimer laser apparatus that outputs ultraviolet laser light at a wavelength of 248 nm and an ArF excimer laser apparatus that outputs ultraviolet laser light at a wavelength of 193 nm
Data Source
AI summary
Problem: to suppress the number of times complete gas replacement in a laser chamber.Solution: this excimer laser apparatus may include a gas supply unit, connected to a first receptacle that holds a first laser gas containing halogen gas and a second receptacle that holds a second laser gas having a lower halogen gas concentration than the first laser gas, that supplies the first laser gas and the second laser gas to the interior of the laser chamber. Then, gas pressure control in which the gas supply unit supplies the second laser gas to the interior of the laser chamber or a gas exhaust unit partially exhausts gas from within the laser chamber, and partial gas replacement control in which the gas supply unit supplies the first laser gas and the second laser gas to the interior of the laser chamber and the gas exhaust unit partially exhausts gas from within the laser chamber sequentially, may be selectively performed.