High-Precision Pressure Regulator for EUV Target Supply
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Solution Overview
Problem
In extreme ultraviolet light source apparatuses using the LPP system, variations in gas pressure and target material temperature lead to uneven exposure due to inconsistent plasma formation, which affects the focus position of the EUV light, causing issues in microfabrication processes for semiconductor devices.
Innovation Solution
A target supply apparatus with a high-precision pressure regulator controls gas pressure inside a tank storing a liquid target material, maintaining pressure variations within a predetermined range to stabilize the plasma formation and reduce velocity variations of the target material, thereby ensuring consistent EUV light focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pressure regulator is used to control gas pressure in the tank, then the device complexity is reduced, but the manufacturing precision deteriorates due to insufficient pressure control accuracy
Solution Approach 1:
The pressure regulation system is segmented into two independent stages: a conventional pressure regulator for coarse pressure adjustment and a newly introduced high-precision pressure regulator for fine pressure control. This segmentation allows each regulator to perform its specialized function optimally, with the conventional regulator handling broad pressure ranges and the high-precision regulator providing the necessary accuracy for stable plasma formation.
Solution Approach 2:
The high-precision pressure regulator acts as an intermediary component between the gas supply and the tank, specifically positioned in the gas passage to provide intermediate fine-tuning of the gas pressure. This intermediary high-precision regulator refines the pressure output from the conventional regulator, ensuring the target material is supplied with the required precision without requiring the entire system to be redesigned.
2Reliability
If gas pressure is not precisely controlled, then the device complexity is reduced, but the reliability deteriorates due to inconsistent plasma formation and focus position variation
Solution Approach 1:
The pressure control system is divided into two functional segments: a conventional pressure regulator for basic pressure management and a high-precision pressure regulator for maintaining consistent plasma formation conditions. This segmentation ensures that the reliability of plasma formation is improved by the high-precision component while the overall system architecture remains manageable through the use of standard components for the bulk pressure control.
Solution Approach 2:
The high-precision pressure regulator serves as a mediating device in the gas supply path, specifically positioned to fine-tune the pressure of gas entering the tank. This intermediary component ensures that despite variations in the broader pressure control system, the actual gas pressure affecting plasma formation remains consistent, thereby improving reliability without requiring complete system redesign.
3Manufacturing precision
If a high-precision pressure regulator is added to the gas passage, then the manufacturing precision is improved through better pressure control, but the device complexity increases
Solution Approach 1:
The gas supply system is segmented into two pressure control stages: a conventional pressure regulator for coarse adjustment and a high-precision pressure regulator for fine adjustment. This segmentation allows the high-precision regulator to focus specifically on the critical task of maintaining accurate pressure for target material supply, while the conventional regulator handles the broader pressure management, thus improving precision without requiring complete system replacement.
Solution Approach 2:
The high-precision pressure regulator is introduced as an intermediary component in the gas passage between the conventional regulator and the tank. This intermediary device refines the pressure output from the conventional regulator, providing the necessary precision for target material supply while maintaining the existing conventional regulator for overall pressure management, thereby limiting the increase in system complexity.
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 pressure and temperature variations, minimizing uneven exposure in the exposure apparatus and enhancing the precision of microfabrication processes for semiconductor devices by maintaining the focus position of the EUV light within a predetermined range.
Implementation Method 1
a high-precision pressure regulator arranged on the gas passage and regulating a pressure of gas flowing the gas passage
Implementation Method 2
controls a gas pressure inside a tank storing a liquid target material to be outputted from a nozzle
Implementation Method 3
a target material supplied inside a vacuum chamber is excited by irradiation with a laser light and thus be turned into plasma
Implementation Method 4
a cocktail light with various wavelength components including an EUV light is emitted from the generated plasma
Implementation Method 5
the EUV light source apparatus focuses the EUV light by reflecting the EUV light using an EUV collector mirror which selectively reflects an EUV light with a desired wavelength
Implementation Method 6
a multilayer coating with a structure in that thin coating of molybdenum (Mo) and thin coating of silicon (Si) are alternately stacked, for instance, is formed. The multilayer coating exhibits a high reflectance ratio
Data Source
AI summary
A target supply apparatus controls a gas pressure inside a tank storing a liquid target material to be outputted from a nozzle by a pressure of gas supplied from a gas supply having a pressure regulator. The target supply apparatus comprises a gas passage introducing gas supplied from the gas supply into the tank, and a high-precision pressure regulator arranged on the gas passage and regulating a pressure of gas flowing the gas passage. The high-precision pressure regulator is able to regulate pressure with accuracy higher than the pressure regulator.