Patent ID: 8680495

Claim:
A method comprising: releasing a stream of target material droplets toward a target region, the droplets in the stream traveling along a trajectory from a target material supply system to the target region; producing a spatially-extended target distribution by directing a first pulse of light along a direction of propagation toward a first target material droplet while the first droplet is between the target material supply apparatus and the target region, the impact of the first pulse of light on the first target material droplet increasing a cross-sectional diameter of the first target material droplet in a plane that faces the direction of propagation and decreasing a thickness of the first target material droplet along a direction that is parallel to the direction of propagation; positioning an optic to establish a beam path that intersects the target location; coupling a gain medium to the beam path; and producing an amplified light beam that interacts with the spatially-extended target distribution to produce plasma that generates extreme ultraviolet (EUV) light by scattering photons emitted from the gain medium off of the spatially-extended target distribution, at least some of the scattered photons placed on the beam path to produce the amplified light beam.