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Center for Nonlinear Studies |
The smallest features on today’s most advanced computer chips are printed using extreme ultraviolet (EUV) radiation at a wavelength of 13.5 nm. This technology, known as EUV lithography, will enable the continued extension of Moore’s law (the number of transistors on an integrated circuit doubles every two years) for many years to come. The radiation that is so crucial to this technology is produced in a hot and dense plasma formed by firing a series of laser pulses onto tin microdroplet targets. In the latest industrial machines, the process of EUV generation occurs a staggering 50,000 times every second! This requirement, which ensures a high wafer throughput, introduces a plethora of challenges to physicists and engineers designing and optimizing EUV sources.
In this talk, I will give an overview of the many physics aspects of EUV light source plasmas. I will start with a discussion of laser-induced hydrodynamics of tin droplets, specifically the propulsion, deformation and fragmentation of droplets. Knowledge of these many aspects is crucial for optimizing the target shape for the high-intensity, EUV-generating laser pulse. I will then proceed to discuss the atomic physics aspects of EUV generation, a topic that I have worked on together with James Colgan and Amanda Neukirch for the past 6 years. Our research has found that the EUV radiation central to computer chip production has a surprising origin: billions of atomic transitions between multiply-excited states in Sn^(11+) - Sn^(14+) ions. I will discuss some of our work on constructing opacity tables for use in radiation-hydrodynamic simulations of EUV sources. Time permitting, I will also discuss our recent work indicating that laser heating drives the formation of super-Gaussian electron distribution functions in these plasmas.
Bio: John Sheil is leader of the Plasma Theory and Modeling (PTM) group at the Advanced Research Center for Nanolithography (Amsterdam, the Netherlands) and is an Assistant Professor at the Vrije Universiteit Amsterdam. He received his PhD in 2019 from University College Dublin for research on the structures and spectra of lanthanide and actinide ions. In 2021 he started the PTM group. The research activities of the group are largely focused on the analytical and numerical modeling of laser-produced plasma radiation sources for nanolithography. Research conducted by the group spans topics in atomic physics, non-LTE population kinetics, radiation transport, laser-plasma interaction, and the physics of plasma expansion.
John and his PhD student, Bowie Brewster, are available to meet now through 2/18/26 with those who are interested. They are visiting James Colgan, sitting in the T-DO corner on the second floor of 03-0123. Feel free to stop by or email Lydia Menzer at lydia.menzer@lanl.gov to set up a meeting.
Join in person in T-4 or via Teams:
Meeting ID: 215 287 113 913 59
Passcode: Qw7gC267
Host: James Colgan, Acting Theoretical Division Leader