Provided is a reflective optical element that is lightweight and excellent in damping capacity. In the reflective optical element, a resin layer having an optical surface is formed on a metal substrate, and a reflective film is formed on the optical surface, and also, the metal substrate includes an alloy containing Mg as a main component.

A radiation source apparatus includes a vessel, a laser source, a collector, and a reflective mirror. The vessel has an exit aperture. The laser source is at one end of the vessel and configured to excite a target material to form a plasma. The collector is disposed in the vessel and configured to collect a radiation emitted by the plasma and to direct the collected radiation to the exit aperture of the vessel. The reflective mirror is in the vessel and configured to reflect the laser beam toward an edge of the vessel.

A radiation source apparatus includes a vessel, a laser source, a collector, and a reflective mirror. The vessel has an exit aperture. The laser source is at one end of the vessel and configured to excite a target material to form a plasma. The collector is disposed in the vessel and configured to collect a radiation emitted by the plasma and to direct the collected radiation to the exit aperture of the vessel. The reflective mirror is in the vessel and configured to reflect the laser beam toward an edge of the vessel.

A telescope includes an initial telescope comprising a concave first mirror and a convex second mirror that are configured so that they form, from a light beam coming from infinity, an image called the intermediate image in a focal plane called the intermediate focal plane, the intermediate image having a largest dimension along an X-axis perpendicular to an optical axis of the telescope, a segmenting module comprising a first set of n segmenting mirrors that are placed downstream of the intermediate focal plane and that are configured to divide the intermediate image obtained from the intermediate focal plane into n sub-images, a second set of n refocusing mirrors that are configured to reimage the n sub-images into n images in a focal plane of the telescope, the images being arranged in the focal plane so as to decrease the dimension along X containing the n images, a detecting device placed in the focal plane.

A freeform surface optical telescope imaging system is provided. The freeform surface optical telescope imaging system comprises a primary mirror, a secondary mirror, a compensating mirror, and a spherical mirror. The primary mirror, the secondary mirror, the compensating mirror, and the spherical mirror are spaced from each other. A surface shape of each of the primary mirror and the secondary mirror is a quadric surface. The primary mirror is used as an aperture stop. A surface shape of the compensating mirror is a freeform surface. A surface shape of the spherical mirror is a spherical surface. A light emitted from a light source would be reflected by the primary mirror, the secondary mirror, the compensating mirror, and the spherical mirror to form an image on an image plane.

A lithography system is provided capable of deterring contaminants, such as tin debris from entering into the scanner. The lithography system in accordance with various embodiments of the present disclosure includes a processor, an extreme ultraviolet light source, a scanner, and a hollow connection member. The light source includes a droplet generator for generating a droplet, a collector for reflecting extreme ultraviolet light into an intermediate focus point, and a light generator for generating pre-pulse light and main pulse light. The droplet generates the extreme ultraviolet light in response to the droplet being illuminated with the pre-pulse light and the main pulse light. The scanner includes a wafer stage. The hollow connection member includes an inlet that is in fluid communication with an exhaust pump. The hollow connection member provides a hollow space in which the intermediate focus point is disposed. The hollow connection member is disposed between the extreme ultraviolet light source and the scanner.

A lithography system is provided capable of deterring contaminants, such as tin debris from entering into the scanner. The lithography system in accordance with various embodiments of the present disclosure includes a processor, an extreme ultraviolet light source, a scanner, and a hollow connection member. The light source includes a droplet generator for generating a droplet, a collector for reflecting extreme ultraviolet light into an intermediate focus point, and a light generator for generating pre-pulse light and main pulse light. The droplet generates the extreme ultraviolet light in response to the droplet being illuminated with the pre-pulse light and the main pulse light. The scanner includes a wafer stage. The hollow connection member includes an inlet that is in fluid communication with an exhaust pump. The hollow connection member provides a hollow space in which the intermediate focus point is disposed. The hollow connection member is disposed between the extreme ultraviolet light source and the scanner.

An optical system includes an incident part, a first reflective surface, a second reflective surface, a third reflective surface, and an exit part. The incident part is rotationally symmetric around a central axis. Incident light from the incident part intersects the central axis and enters the first reflective surface. Reflected light from the first reflective surface intersects the central axis and enters the second reflective surface. Reflected light from the second reflective surface enters the third reflective surface.

There is provided a light source unit including a semiconductor light emitting device, and a rotary mirror device having a mirror surface on a first side, and a second side to which a rotational shaft of a motor is connected, wherein the mirror surface has an undulating section shape of convex and concave shape portions, wherein the rotary mirror device is disposed so as to reflect light emitted from the semiconductor light emitting device on the mirror surface.

A reflective beam former for changing a diameter of a collimated light beam. A first mirror surface of a first curvature type, a second mirror surface and a third mirror surface are in a beam path; the shapes of the surfaces cause a collimated light beam entering the beam former via a first or third mirror surface to leave via the third or first mirror surface, respectively. The beam former includes several third, curved mirror surfaces of a second, different curvature type, one type being convex, the other concave. The second mirror surface is a plane mirror surface with an axis perpendicular to the plane mirror surface, and is in the beam path between the first and one selected from the several third mirror surfaces such that the surfaces are confocal to each other. The beam former includes a selector for selecting one of the several third curved mirror surfaces.