Subam Rai successfully defends his thesis

Published on March 7, 2023
Category Ion Interactions
Left: Joost Frenken (University of Groningen) Right: Subam Rai

PhD student Subam Rai successfully defended his thesis ‘Ionic interactions around EUV generating tin plasma’ at the University of Groningen on February 28th.

Rai did his doctoral research in the Ion Interactions group led by Ronnie Hoekstra. Oscar Versolato acted as co-supervisor.

About the thesis
Extreme ultraviolet (EUV) light is used by state-of-the-art nanolithography machines to create microchips that are eventually used in many electronic devices including smartphones, laptops, etc. The EUV light is generated by irradiating molten Sn microdroplets with a high-power pulsed laser, which creates the hot, dense laser produced plasma (LPP) that emits EUV light. However, during this process undesirable products such as energetic Sn ions are also produced which, if not controlled, may damage the expensive multilayer optics in the machine, particularly the EUV collector mirror. With his research Rai contributed to getting a better understanding of the ionic interactions in the source environment that may lead to such damages.