An extreme ultraviolet (EUV) light generator includes a collecting mirror having a first focal point and a second focal point, the first focal point being closer to the collecting mirror than the second focal point, a laser to generate a laser beam and to radiate the laser beam toward the first focal point of the collecting mirror, and a droplet generator to generate a droplet and to discharge the droplet at the first focal point of the collecting mirror, wherein the collecting mirror includes a concave reflective surface, a through hole in a center of the reflective surface, and a drip hole between the through hole and an outer circumferential surface of the reflective surface.

A focusing device for focusing at least two laser beams onto a moving target material in a target region for generating extreme ultraviolet (EUV) radiation is provided. The focusing device includes a first focusing element for focusing a first laser beam onto the target material at a first position in the target region, a second focusing element for focusing a second laser beam onto the target material at a second position in the target region, and a reflective optical element for reflecting the EUV radiation generated by the target material. An optical axis of the first focusing element and/or an optical axis of the second focusing element are aligned approximately parallel or congruently with respect to an optical axis of the reflective optical element.

A laser system comprising: a laser operable to generate a laser beam; an optical system comprising a first optical element and a second optical element; and an output through which the laser beam exits the laser system; the laser, optical system and output arranged such that the laser beam travels to the first optical element, the second optical element and the output sequentially; wherein the first optical element has a first focal length, the second optical element has a second focal length equal to the first focal length, and the second optical element is spaced from the first optical element by a distance of two times the first focal length.

An illumination optical unit for EUV projection lithography illuminates an object field with illumination light. The illumination optical unit has a first facet mirror including a plurality of first facets on a first mirror carrier. Disposed downstream of the first facet mirror is a second facet mirror including a plurality of second facets arranged on a second mirror carrier around a facet arrangement center. Partial beams of the illumination light are guided superposed on one another into the object field, respectively via illumination channels which have one of the first facets and one of the second facets. Second maximum angle facets are arranged at the edge of the second mirror carrier. The second maximum angle facets predetermine maximum illumination angles of the illumination light which deviate maximally from a chief ray incidence on the object field.

A system and method of removing target material debris deposits simultaneously with generating EUV light includes generating hydrogen radicals in situ in the EUV vessel, proximate to the target material debris deposits and volatilizing the target material debris deposits and purging the volatilized target material debris deposits from the EUV vessel without the need of an oxygen containing species in the EUV vessel.

Beam guiding devices for guiding a laser beam, in particular in a direction towards a target region for producing extreme ultraviolet (EUV) radiation, include an adjustment device for adjusting a beam diameter and an aperture angle of the laser beam. The adjustment device includes a first mirror having a first curved reflecting surface, a second mirror having a second curved reflecting surface, a third mirror having a third curved reflecting surface, a fourth mirror having a fourth curved reflecting surface, and a movement device configured to adjust the beam diameter and the aperture angle of the laser beam by moving the first reflecting surface and the fourth reflecting surface relative to one another and, independently thereof, moving the second reflecting surface and the third reflecting surface together relative to the first reflecting surface and the fourth reflecting surface.

A device for applying radiation to a target is provided. The device includes a radiation emitter to emit electromagnetic radiation having a peak emission wavelength in the range from 10 nm-1 mm, and a first reflector that extends in a length direction with a concave cross section. The first reflector defines a cavity area having a perimeter, and includes an inward facing reflective border for at least 50% of the perimeter of the cavity area. Radiation is provided to the cavity area with an intensity distribution I and a maximum intensity I.sub.max. The cavity area includes a focal area defined by all points at which a normalized intensity I/I.sub.max is greater than 0.2. A width of the focal area is 0.0001-0.5 times a width of the cavity area.

Multilayer optical film comprising at least a plurality of alternating first and second optical layers. Embodiments of the multilayer optical film are useful, for example, in UV-C shield, UV-C light collimator, and UV-C light concentrator applications.

A grating structure and a UV light, where the grating structure includes at least two up-down baffles provided at intervals, the upper surface and the lower surface of each baffle is provided with a light absorption layer, two adjacent baffles enclose to form a light outlet; in the light emission direction of the light outlet, each baffle includes the incoming light section, the light filter section and the outgoing light section, and the incoming light section, the light filter section and the outgoing light section are respectively the first plate body, second plate body and third plate body connected in sequence, the upper surface and the lower surface of the light filter section are provided respectively with multiple upper convexes and multiple lower convexes, the height difference of the top of the upper convexes and the bottom of the lower convexes is greater than 1.5 mm.

An EUV collector for use in an EUV projection exposure apparatus includes at least one mirror surface having surface structures for scattering a used EUV wavelength () of used EUV light. The mirror surface has a surface height with a spatial wavelength distribution between a lower limit spatial wavelength and an upper limit spatial wavelength. An effective roughness (rmsG) below the lower limit spatial wavelength (PG) satisfies the following relation: (4 rmsG cos()/)2<0.1. denotes an angle of incidence of the used EUV light at the mirror surface. The following applies to an effective roughness (rmsGG) between the lower limit spatial wavelength (PG) and the upper limit spatial wavelength (PG): 1.5 rmsG<rmsGG<6 rmsG.