Apparatus for generating light in the extreme ultraviolet and use in a light source for extreme ultraviolet lithography

A device for generating light in the extreme ultraviolet (EUV), the device comprising:

• a) a plurality of power laser sources for emitting a plurality of laser beams;
• b) a focusing device for focusing the laser beams to produce focused laser beams;
• c) a device for creating an evacuated space with pressure lower than 1 Pa at least in the zone where said focused laser beams are focused;
• d) a device for creating a dense target in said space where said focused laser beams are focused, the dense target being suitable for interacting with said focused laser beams to emit a plasma possessing at least one emission line in the extreme ultraviolet;
• e) a receiver device for receiving the target after it has interacted with said focused laser beams;
• and
• f) at least one first device for collecting the EUV radiation emitted by the target;
• the device being characterized in that it has a mean collection axis for EUV radiation perpendicular to the axis defined by the essentially linear dense target;
• in that the focusing device for focusing the laser beams on the target is arranged in such a manner that the laser beams are focused laterally on the target while being situated in a common half-space relative to the target and while being inclined at a predetermined angle (β) lying in the range about 60° to about 90° relative to said mean collection axis;
• and in that said first collector device is disposed symmetrically about said mean collection axis in the half-space containing the laser beams focused on the target and within a conical space centered on the mean collection axis with its vertex situated on the target and a half-angle (α) at the vertex less than the angle of inclination (β) of the focused laser beams relative to the mean collection axis.