Efficient laser-produced plasma extreme ultraviolet sources using grooved Sn targets

An efficient extreme ultraviolet (EUV) generation method has been developed with the use of a CO(2) laser-produced plasma from a grooved target. A similar to 5% conversion efficiency from laser to 13.5 nm photons was obtained with the use of grooves in a tin target or by repeated laser pulse shots at the same target position. Modeling studies proved that the groove target controls the hydrodynamic expansion of the plasma leading to confinement which prevents the plasma escaping from the EUV production zone.