Meet Dmitry Kurilovich, PhD student at ARCNL

‘Plasma physics had me from the start’

It all started with a fascination for astronomy and satellites. At school in Moscow, Kurilovich was intrigued by the techniques to keep satellites in their orbit. ‘Many of them use plasma, a hot, gas-like state of matter that consists of electrically charged particles that can be accelerated. This so-called plasma propulsion involves a lot of exciting physics and much engineering too,’ he says. ‘It just had me from the start.’

From plasmas to invisible light
His fascination for plasma physics made Kurilovich apply to the prestigious Bauman Moscow State Technical University, where he got through the tough competition and specialised in plasma physics. Before moving to the Netherlands, he was a junior researcher for two years. Kurilovich: ‘I worked at an exciting new lab: at the Research Center for Plasma Science and Technology in Moscow. This lab is a collaboration between my university and the Max Planck Institute for Extraterrestrial Physics, where we studied many different applications of plasma physics. One of them involved plasma to create multilayer structures like those used for reflecting Extreme Ultraviolet (EUV) light. Normal lenses are useless, because EUV light is strongly absorbed by matter. This brought me to the source of EUV light itself.’

Public-private partnership
Kurilovich was looking for a PhD position in Europe when ARCNL started hiring in 2014. Again, he stepped into a brand-new research institute. He was one of the first PhD students to start at the Amsterdam-based institute that is a public-private partnership of NWO, the two local universities and semiconductor equipment manufacturer ASML. The main reason to found this new research institute was the need for fundamental research for tomorrow’s nanolithography. During the four years of Kurilovich’s PhD project in the EUV Plasma Processes group led by professors Ubachs, Hoekstra, and Dr. Versolato, ARCNL grew into an institute with nearly ninety people working in research and support. Its ten research groups focus on the physics and chemistry involved in key nanolithography technologies. ARCNL just moved to a state-of-the-art new building with a lab floor that is mechanically separated from the rest of the building to accommodate their delicate experiments.

EUV for producing computer chips
Research at ARCNL is inspired by the Dutch nanolithography industry, which applies EUV light in its machines for producing the next generation chips for computers, smartphones and many other small but powerful electronic devices. With its very short wavelength, EUV light can print extremely small patterns. One of the challenges lies in producing this EUV light, because conventional light sources and lasers are unavailing.
Kurilovich spent the first part of his PhD period building the experimental set-up that is now used by two large groups at ARCNL. It creates a sequence of very small tin droplets and uses laser pulses to make these droplets hot enough to become a plasma emitting a flash of EUV light. This happens in two stages. A first laser pulse hits the droplet, causing it to accelerate and deform. After that a second, far more powerful laser pulse ensures the knock-out: the deformed droplet changes into an EUV-emitting plasma. The set-up can accommodate many different techniques to investigate exactly what happens at a fundamental level. Kurilovich’s own experimental work concentrated on investigating how the first laser pulse accelerates and deforms the tin droplet upon impact. This shaping of a tin droplet is necessary for efficient generation of the desired EUV light when it is hit by the next laser pulse and turned into plasma.

Next step: ASML
Although he does see some differences, Kurilovich had no problems with settling in the Netherlands. ‘The work was sometimes lonely at first, because there were no other PhD students in my group yet, but I felt very lucky because of the excellent support I got from our technical staff. Without them it would have taken much longer to get the experiments running,’ he says. ‘I do think work is more efficient here. And for me, the Netherlands also offers very good career options, because there are so many successful high-tech companies.’
Kurilovich will defend his thesis in spring 2019, but in January he already started working for ASML. His career sticks to a common thread; the plasma physics he studied in Russia led him to develop plasma sources for manufacturing structures that reflect EUV light. At ARCNL he dived into exploring the best ways to create such light by turning droplets of tin into plasma. In his job at ASML he will continue to work on the source of EUV light and its application in lithography. ‘My work will be closely related to what happens at ARCNL, so I expect regular visits to Amsterdam,’ says Kurilovich. ‘In the future, I hope to continue in this field of fundamental physics that is strongly connected to industrial development.’

Newsletter Inside NWO-I, Februari 2019