Compact EUV Storage Ring Free Electron Laser
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Solution Overview
Problem
Current plasma-based EUV lithography sources face challenges in achieving high power levels required for next-generation semiconductor manufacturing, leading to limitations in wafer throughput and sensitivity due to low usable EUV power.
Innovation Solution
A compact low-energy electron storage ring system is used to generate high power EUV radiation through free-electron laser technology, utilizing a magnetic undulator and electron injector to produce coherent radiation, allowing for a more compact, affordable, and efficient EUV source with average power ranging from 1 kW to 3 kW.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If plasma-based sources are used for EUV lithography, then EUV radiation is produced, but the usable EUV power is limited to low levels (below 250 W)
Solution Approach 1:
The patent replaces the plasma-based generation mechanism with a free-electron laser system. Instead of using plasma to generate EUV radiation, the invention uses a relativistic electron beam passing through a magnetic undulator to produce coherent EUV radiation through synchrotron radiation and stimulated emission processes, fundamentally changing the physical mechanism of radiation generation.
Solution Approach 2:
The patent changes key parameters of the electron beam including energy (100 MeV to 3 GeV range), current, and emittance to optimize EUV power output. By adjusting these parameters and using multiple electron bunches in a storage ring, the system achieves scalable high power output that can reach 1 kW to 3 kW range, overcoming the power limitations of plasma sources.
2Manufacturing precision
If plasma-based sources operate at low power, then shot noise induced roughness occurs, but increasing power is not reliably achievable
Solution Approach 1:
The free-electron laser system replaces plasma-based generation, providing coherent EUV radiation that reduces shot noise effects. The coherent nature of the radiation from the organized electron beam and undulator interaction produces more stable intensity profiles, reducing the shot noise induced roughness that plagues low-power plasma sources.
Solution Approach 2:
The storage ring configuration allows continuous circulation of electron bunches, providing continuous EUV radiation output. Multiple bunches can be stored and circulated simultaneously, enabling continuous high-power operation without the intermittent nature of pulsed plasma sources, thereby maintaining stable power levels that prevent roughness while achieving high average power.
3Productivity
If plasma-based sources are used, then EUV radiation is generated, but wafer throughput is limited due to low power
Solution Approach 1:
The storage ring enables continuous operation with multiple electron bunches circulating and generating EUV radiation continuously. This continuous high-power output directly increases wafer throughput by providing sufficient photons per unit time to process wafers faster, overcoming the throughput limitation of low-power plasma sources.
Solution Approach 2:
The system uses periodic injection of electron bunches into the storage ring at the revolution frequency, creating a train of synchronized EUV pulses. This periodic high-power delivery allows for optimized exposure cycles that increase productivity while maintaining the necessary power levels for high-volume manufacturing.
4Power
If conventional electron storage rings are used for FEL, then high power EUV is achieved, but system size becomes very large
Solution Approach 1:
The patent uses lower electron energies (100 MeV to 3 GeV) compared to conventional high-energy storage rings, which reduces the circumference required for a given momentum compaction factor. This parameter change allows achieving the necessary EUV power through optimized bunching and undulator design rather than relying on high energy and large circumference, thereby reducing system footprint.
Solution Approach 2:
The system segments the electron beam into multiple bunches with specific spacing and timing, allowing the use of a compact storage ring with fewer turns. By optimizing the number of bunches, their charge, and spacing, the system achieves high average power in a reduced circumference ring, avoiding the need for very large conventional storage rings.
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 compact EUV source system achieves high average power while reducing system size and costs, enabling high-volume manufacturing at smaller node sizes and overcoming limitations of traditional EUV lithography sources.
Implementation Method 1
A compact low-energy electron storage ring system is used to generate high power EUV radiation through free-electron laser technology
Implementation Method 2
utilizing a magnetic undulator and electron injector to produce coherent radiation
Data Source
AI summary
A high power extreme ultraviolet (EUV) beam is produced. An electron beam is injected in a compact electron storage ring configured for emission of free-electron laser (FEL) radiation. The electron beam is passed through a magnetic undulator on each of a plurality of successive revolutions of the electron beam around the compact electron storage ring. The electron beam is induced to microbunch and radiate coherently while passing through the magnetic undulator. A portion of the free-electron laser radiation at an extreme ultraviolet wavelength produced by an interaction of the electron beam through the magnetic undulator is outputted.