Laser produced plasma EUV light source

A device comprising:

• a system generating a plasma at a plasma site, the plasma producing EUV radiation and ions exiting the plasma
• an optic distanced from the site by a distance, d;
• a gas comprising a halogen, the gas disposed between the plasma and optic, the gas establishing a gas pressure sufficient to operate over the distance, d, to reduce ion energy below 100eV before the ions reach the optic.

A device comprising:

• a system generating a plasma at a plasma site, the plasma producing EUV radiation and ions exiting the plasma, the system comprising an irradiation source having a pulse shaper, the source producing a pulse-shaped beam for irradiating a target material to produce a plasma having lower initial ion energies than a corresponding unshaped beam:
• an optic distanced from the site by a distance, d;
• a gas disposed between the plasma and optic, the gas establishing a gas pressure sufficient to operate over the distance, d, to reduce ion energy below 100 eV before the ions reach the optic.