Excimer Laser Gas Circulation With Xenon Feedback Control
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Solution Overview
Problem
The challenge in semiconductor exposure apparatuses is the wide spectral linewidth of laser light from KrF and ArF excimer lasers, which causes chromatic aberrations in projection lenses, reducing resolution. To mitigate this, a line narrowing module is used, but there is a need for a more effective method to manage the spectral linewidth and maintain optimal xenon concentration in the gas circulating system.
Innovation Solution
A laser apparatus with a gas circulating system that merges exhaust gases, includes a fluorine trap to remove fluorine, and a xenon adder to adjust the xenon concentration, ensuring the xenon concentration in the exhaust gas is maintained within an optimal range to compensate for variations and support stable laser performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gas circulating system merges exhaust gases from multiple laser apparatuses, then gas circulation efficiency is improved, but xenon concentration varies and becomes difficult to control
Solution Approach 1:
A concentration detection device measures the xenon concentration in the circulating gas, and a control device adjusts the additive gas supply based on the detection result to maintain stable xenon concentration despite merging exhaust gases from multiple laser apparatuses
Solution Approach 2:
The system dynamically adjusts the xenon concentration parameter by controlling the flow rate of additive gas based on detected concentration levels, allowing the system to adapt to varying conditions while maintaining optimal performance
2Reliability
If xenon concentration in exhaust gas is increased to compensate for variations, then laser performance stability is improved, but gas composition control complexity increases
Solution Approach 1:
The concentration detection device provides real-time feedback on xenon concentration, enabling automatic adjustment of additive gas supply to maintain stable laser performance without requiring complex manual control procedures
Solution Approach 2:
The system automatically regulates its own gas composition by detecting xenon concentration levels and adjusting additive gas supply accordingly, eliminating the need for external intervention or complex control mechanisms
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 configuration effectively narrows the spectral linewidth, reducing chromatic aberrations and maintaining optimal xenon concentration, thereby enhancing the resolution and stability of the laser apparatuses, ensuring consistent performance in semiconductor manufacturing.
Implementation Method 1
a fluorine trap connected to a halfway point of the exhaust pipe and configured to remove at least fluorine from the exhaust gas exhausted from the laser chamber
Implementation Method 2
a xenon adder connected to a halfway point of the exhaust pipe and configured to add an additive gas having a xenon concentration higher than a xenon concentration in the fresh gas to the exhaust gas exhausted from the laser chamber
Implementation Method 3
A laser apparatus according to an aspect of the present disclosure includes a laser chamber connected to a gas circulating system
Data Source
AI summary
A laser apparatus includes a laser chamber connected to a gas circulating system including a merging pipe where exhaust gases exhausted from multiple laser apparatuses merge with each other, and configured to select one of a fresh gas containing xenon and a circulating gas flowing through the merging pipe and supply the multiple laser apparatuses with the selected gas; an exhaust pipe which is connected to and between the laser chamber and the merging pipe, and through which the exhaust gas exhausted from the laser chamber flows toward the merging pipe; a fluorine trap connected to a halfway point of the exhaust pipe and configured to remove fluorine from the exhaust gas; and a xenon adder connected to a halfway point of the exhaust pipe and configured to add an additive gas having a xenon concentration higher than a xenon concentration in the fresh gas to the exhaust gas.