Dynamics of EUV-induced plasma adjacent to an electrostatic chuck

In extreme ultraviolet (EUV) lithography, high-energy photon pulses generate transient plasmas and thus can degrade lithography system performance. This study investigates the dynamics of EUV-induced plasma adjacent to an electrostatic chuck, with a focus on the coupling mechanism between the plasma and the applied electric field. First-principle particle-in-cell simulations demonstrate that photoelectron emission serves as the dominant mechanism for electron production during an EUV pulse. Concurrently, electron-induced secondary emission significantly alters the potential distribution and electron density within positively biased regions, thereby modulating local plasma density. The space charge separation and the associated distortion of the electric field lead to anomalous electron and ion energy distributions, which in turn enhance ion sputtering on ruthenium surfaces. During the post-EUV-pulse phase, ion-induced secondary electron emission becomes the dominant source of electrons, sustaining the plasma during its gradual decay. The applied electric field established between the grounded blade and the reticle surface facilitates the extraction and loss of ions, thereby accelerating local ion density decay. Spatiotemporal electron and ion energy distribution functions and ion fluxes indicate that the EUV-induced plasma transitions from a photoionization-dominated to a sheath-controlled state. These findings provide deep insights into the evolution of EUV-induced plasmas and enhance the understanding of particle sputtering-induced damage under coupled conditions, laying the foundation for improving pattern fidelity and process stability in nanolithography.