Ablation of Submicrometer Holes Using an Extreme-Ultraviolet Laser

• DOI: 10.1103/physrevapplied.3.064013
• Publication Date: 2015-06-19T13:08:25Z
• Authors: Andrew K. Rossall; Valentin Aslanyan; Greg J. Tallents; Ilya Kuznetsov; Jorge J. Rocca; Carmen S. Menoni
• Keywords: 0103 physical sciences; 01 natural sciences; QC

Simulations and experiments are used to study extreme-ultraviolet (EUV) laser drilling of submicrometer holes. The ablation process is studied with a 2D Eulerian hydrodynamic code that includes bound-free absorption processes relevant to the interaction of EUV lasers with a solid material. Good agreement is observed between the simulated and measured ablated depths for on-target irradiances of up to 1×1010 W cm−2. An increase in the irradiance to 1×1012 W cm−2 is predicted to ablate material to a depth of 3.8 μm from a single pulse with a hole diameter 3 to 4 times larger than the focal spot size. The model allows for the simulation of the interaction of a laser pulse with the crater created by a previous shot. Multiple-pulse lower-fluence irradiation configurations under optimized focusing conditions, i.e., approaching the diffraction limit, are shown to be advantageous for applications requiring mesoscale [(100 nm)–(1 μm)] features and a high level of control over the ablation profile.