Abstract: An optical collector (15) for collecting extreme ultraviolet radiation or EUV light generated at a central EUV production site comprises a reflective shell (25). To cope with thermal loading of the collector and avoid deformations, the reflective shell (25) is mounted on a support structure (24), such that a cooling channel (29) is established between the back side of the reflective shell (25) and the support structure (24), the thickness of the reflective shell (25) is substantially reduced, such that the convective heat transfer between the back side of the reflective shell (25) and a cooling medium (26) flowing through the cooling channel (29) dominates the process of removing heat from the reflective shell (25) with respect to heat conduction, and a cooling circuit (33) is connected to the cooling channel (29); to supply a cooling medium (26) to the cooling channel (29) with a controlled coolant pressure and/or mass flow.

Abstract: The invention relates to a beam line (30) for a source of extreme ultraviolet (EUV) radiation, wherein a EUV-radiating plasma is generated by irradiating droplets of a suitable target material with a focused laser beam (5) at a plasma generation point, said beam line (30) comprising within a vacuum chamber (7): a beam delivery system (2) comprising a focusing lens and means for cooling and shielding said focusing lens; a EUV mirror collector (1), which collects and focuses the radiated EUV in a EUV beam (6) at an intermediate focus (IF); a beam dump (3) capable of damping at least a portion of the laser beam (5) without imposing a shadow on the collected and focused EUV beam (6); and an intermediate focus module (4) for blocking particles from leaving the vacuum chamber (7) with the EUV beam (6).

Abstract: An optical collector (15) for collecting extreme ultraviolet radiation or EUV light generated at a central EUV production site comprises a reflective shell (25). To cope with thermal loading of the collector and avoid deformations, the reflective shell (25) is mounted on a support structure (24), such that a cooling channel (29) is established between the back side of the reflective shell (25) and the support structure (24), the thickness of the reflective shell (25) is substantially reduced, such that the convective heat transfer between the back side of the reflective shell (25) and a cooling medium (26) flowing through the cooling channel (29) dominates the process of removing heat from the reflective shell (25) with respect to heat conduction, and a cooling circuit (33) is connected to the cooling channel (29); to supply a cooling medium (26) to the cooling channel (29) with a controlled coolant pressure and/or mass flow.