Abstract:
An apparatus and method for generating extreme ultra violet EUV radiation includes a light source providing light to a laser medium to generate a first laser, a droplet generator to provide a droplet to reflect the first laser to one end of the laser medium, a laser generator positioned at the opposite end of the laser medium from that of the droplet and a second laser to expand the droplet or not and to thereby control the conversion efficiency and dose of the EUV generation apparatus.