EUV Photoemission

This joint group of ARCNL and AMOLF uses photoelectron spectroscopy – detecting electrons knocked out of a material by incoming photons – to study molecular properties of EUV photoresist materials and of liquid interfaces.

In the latest nanolithography machines a pattern is transferred to a wafer by focusing EUV light on a photosensitive layer called photoresist. The aim of this group is to understand at a molecular level how the absorption of incident EUV photons leads to a chemical change in the resist.

When EUV photons are absorbed, electrons are knocked out of the resist’s molecules. These electrons, and the so-called secondary electrons they give rise to, are responsible for the final chemical change in the resist. The kinetic energy of the electrons determines the distance they can travel, and hence the area in which the resist is developed. ARCNL directly measures the kinetic energy distribution of the electrons to probe their behavior in the resist and the chemical states of the constituent molecules. The group studies how the chemistry evolves over time and how it changes as a function of radiation doses.

Furthermore, this group uses photoelectron spectroscopy to study the distribution of different molecules in the outer layer of liquids. Few other techniques are suitable for this. This research is relevant for a range of technological, biological, and climatological applications.