EUV Radiation Source Fuel Contamination Control
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Solution Overview
Problem
Lithographic apparatuses using extreme ultraviolet (EUV) radiation sources face contamination issues within nozzles, leading to inaccurate droplet trajectories and reduced radiation generation efficiency due to particulate contamination, which is challenging to address without causing blockages in the fuel flow system.
Innovation Solution
A contamination control arrangement utilizing a combination of magnetic and electric fields is applied at potential contamination locations within the fuel stream, ensuring non-parallel field lines to drive contamination away from the nozzle, thereby maintaining nozzle integrity and radiation source performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous stream of fuel droplets is directed through a nozzle, then radiation generation efficiency is improved, but contamination accumulates on the nozzle internal surface causing trajectory inaccuracy
Solution Approach 1:
The patent extracts and removes contamination from the fuel stream using a filter system positioned upstream of the nozzle. The filter captures particulate matter and other contaminants before they can accumulate on the nozzle internal surface, thereby maintaining droplet trajectory accuracy while allowing continuous operation.
Solution Approach 2:
The patent implements preliminary filtration of the fuel stream before it enters the nozzle. By pre-filtering the fuel to remove contaminants, the system prevents contamination accumulation on the nozzle internal surface, ensuring consistent droplet trajectory and radiation generation efficiency over time.
2Manufacturing precision
If filtration systems are added to remove contamination, then droplet trajectory accuracy is maintained, but device complexity increases
Solution Approach 1:
The patent applies filtration only at specific critical locations in the fuel stream path where contamination would most adversely affect nozzle performance. By strategically positioning filters at key points rather than filtering the entire system, the design maintains trajectory accuracy while minimizing added complexity.
3Manufacturing precision
If the nozzle is cleaned or maintained, then contamination is removed, but radiation source downtime increases
Solution Approach 1:
The patent enables continuous operation of the radiation source by implementing an online filtration system that continuously removes contamination from the fuel stream. This eliminates the need for periodic nozzle cleaning or maintenance downtime, allowing the system to operate continuously without interruption.
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 magnetic and electric field control effectively prevents contamination from entering sensitive areas, maintaining the nozzle's effective geometry and ensuring stable radiation generation, reducing downtime and maintenance needs.
Implementation Method 1
a magnetic field generation element for generating a magnetic field
Implementation Method 2
an electric field generation element for generating an electric field
Implementation Method 3
a laser configured to direct laser radiation at the stream at the plasma formation location to generate, in use, a radiation generating plasma
Implementation Method 4
The plasma may be created, for example, by directing a laser beam at a fuel... The resulting plasma emits output radiation, e.g., EUV radiation
Data Source
AI summary
A radiation source is disclosed that comprises a reservoir that retains a volume of fuel, a nozzle configured to direct a stream of fuel towards a plasma formation location, a laser configured to generate a radiation generating plasma, and a fuel contamination control arrangement. The contamination control arrangement comprises a magnetic field generation element for generating a magnetic field; an electric field generation element for generating an electric field, the magnetic field generation element and the electric field generation element together configured to ensure that the magnetic field and the electric field overlap at a location of contamination within the fuel, and to ensure that lines of flux of the magnetic field and electric field are non-parallel at that location to control movement of the contamination.