CO2 Beamline Variation Reduction in EUV Laser Gas Control
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Solution Overview
Problem
Natural fluctuations in CO2 concentrations in air cause instability in drive laser beam diameter, leading to fluctuations in EUV radiation energy and maintenance issues in semiconductor processing, which existing industrial compressed dry air production processes fail to control effectively.
Innovation Solution
A system and method for controlling a gas mixture by generating a custom blend of air constituents, such as nitrogen, oxygen, and argon, to maintain a stable CO2 concentration within a threshold range, using precision flow controllers and monitoring feedback loops to ensure precise control and stability of the laser beam diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If industrial compressed dry air production processes are used, then air supply is provided for the laser system, but CO2 concentration fluctuations are not controlled, causing laser beam diameter instability
Solution Approach 1:
The gas mixture control system is segmented into multiple independent components: a gas mixing module that combines purified air with controlled CO2 removal, and a separate monitoring module with CO2 sensors. This segmentation allows each component to be optimized independently, achieving stable CO2 concentration control without requiring complete system redesign.
Solution Approach 2:
The system performs preliminary CO2 concentration measurement and adjustment before the gas reaches the laser beam path. By pre-controlling the CO2 levels in the compressed dry air through active removal mechanisms and blending with purified air, the laser beam diameter stability is ensured before any fluctuations can occur in the processing zone.
2Manufacturing precision
If CO2 concentration is not controlled, then the gas supply system remains simple, but laser beam diameter fluctuations and EUV radiation energy variations occur
Solution Approach 1:
The system implements continuous feedback control by monitoring CO2 concentration levels in real-time using integrated sensors and dynamically adjusting the gas mixture composition. The control system compares measured CO2 levels against target values and automatically modifies the blending ratio between purified air and ambient air, or activates CO2 removal mechanisms, to maintain precise CO2 concentration and ensure consistent EUV radiation energy output.
Solution Approach 2:
The system actively changes the CO2 concentration parameter of the gas mixture by dynamically adjusting the blending ratio of purified air to ambient air, or by controlling CO2 removal rate. This parameter control directly stabilizes the refractive index of the gas along the laser beam path, ensuring consistent laser beam diameter and EUV radiation energy without requiring complex hardware modifications to the laser system itself.
3Stability of the object's composition
If drying processes are used to produce compressed dry air, then moisture is removed, but CO2 concentration fluctuations are exacerbated, causing beam diameter dips and oscillations
Solution Approach 1:
The system extracts and removes CO2 from the compressed dry air stream using dedicated CO2 removal mechanisms such as selective adsorption materials or membrane separation. By specifically targeting and removing CO2 while preserving the dried air composition, the system eliminates the harmful CO2 concentration fluctuations that cause beam diameter dips and oscillations, maintaining both dryness and compositional stability.
Solution Approach 2:
The system uses composite gas mixture control by combining purified dry air with precisely controlled amounts of CO2-free gas or by integrating multiple gas treatment mechanisms. This composite approach creates a stable gas mixture with controlled CO2 levels that maintains the benefits of drying while eliminating CO2-induced beam fluctuations, achieving superior composition stability compared to single-process systems.
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 stabilizes the laser beam diameter and EUV radiation energy, reducing maintenance needs and ensuring consistent semiconductor processing by eliminating CO2-induced fluctuations and maintaining a safe, breathable gas mixture.
Implementation Method 1
fluctuations in drive laser beam diameter cause corresponding fluctuations in energy per pulse of EUV scanner radiation
Data Source
AI summary
A method of controlling a gas mixture for a laser includes receiving as an input one or more of a plurality of concentration values. Each of the concentration values respectively corresponds to a constituent of a plurality of constituents of air. In the method, a blend of the plurality of constituents of air is generated based on the received one or more of the concentration values. The method also includes determining whether the blend of the plurality of constituents of air is within a threshold range for a ratio of the concentration values for the plurality of constituents of air. A flow of the blend of the plurality of constituents of air is controlled to be routed through an output circuit for use as the gas mixture for the laser following a determination that the blend of the plurality of constituents of air is within the threshold range.