EUV Light Source

 EUV light source is required on the manufacturing process of semi-conductor devices for next generation. As a national strategic technology, competitive development has been started among Japan, U.S., and Europe.

   We have studied experimentally the EUV emission from laser-irradiated tin targets, while developing a 2-D simulation code. In order to make a bench-mark for developing the EUV light source, we demonstrated high-efficiency and high-power light source with a support of Ministry of Education, Culture, Sports, Science and Technology, Japan.

 Tin droplet with the diameter of 200μm was irradiated by the 1.06μm 10ns laser pulse. Profiles of ion density and electron temperature at the laser peak timing are given by the two-dimensional radiation hydrodynamic simulation.


Concept of “Punch out Target”

 The Punch-out Target is a tin-foil coated on a transparent substrate. A punching-out laser is irradiated from the back side of the substrate. As the tin plasma is produced at the boundary of the foil and substrate, the solid tin-foil (mass-limited) is ejected at high velocity due to the expanding plasma pressure. The main laser pulse heats the flying target to produce EUV emission.

 The method is effective for minimizing the debris mitigation and suitable for fast supply of the tin targets.