A method of cleaning an extreme ultraviolet lithography collector includes applying a cleaning composition to a surface of the extreme ultraviolet lithography collector having debris on the surface of the collector in an extreme ultraviolet radiation source chamber. The cleaning composition includes: a major solvent having Hansen solubility parameters of 25>δ.sub.d>15, 25>δ.sub.p>10, and 30>δ.sub.h>6; and an acid having an acid dissociation constant, pKa, of −15<pKa<4. The debris is removed from the surface of the collector and the cleaning composition is removed from the extreme ultraviolet radiation source chamber.

An extreme ultraviolet light generation device may include a chamber in which extreme ultraviolet light is generated from plasma, the plasma generated by irradiation of a target supplied in a plasma generation region inside of the chamber with laser light; a condenser mirror collecting the extreme ultraviolet light and guiding it to outside of the chamber; a first etching gas supply unit blowing an etching gas to a reflective surface of the condenser mirror and the plasma generation region; a magnet forming a magnetic field in the chamber; a port that intersects a central axis of the magnetic field and that takes in suspended substances generated in the chamber; and an ejection path that is in communication with the port and that ejects the suspended substances taken from the port to the outside of the chamber.

An optical apparatus may include a housing having an opened front face, an optical unit freely movable into and out of an internal space of the housing through the front face, and a positioning portion disposed on a back side of the optical unit in the internal space. A base plate of the optical unit may include first and second convex portions disposed on a base end face of the base plate. The second convex portion may be disposed at a position different from the first convex portion in a width direction of the base plate. The positioning portion may include a V block having a V groove shape at a part contacting the first convex portion, and a flat block having a flat surface shape at a part contacting the second convex portion. The optical unit may be positioned in the internal space through the contact.

A method of cleaning a collector of an extreme ultraviolet light source system includes introducing the collector separated from the extreme ultraviolet light source system into a chamber; capturing an optical image of a reflective surface of the collector; measuring a contamination level of the reflective surface by comparing the optical image with a prestored standard image; performing a first cleaning operation if the contamination level exceeds a preset first reference value, the first cleaning operation including cleaning the reflective surface by spraying dry ice particles onto the reflective surface; and performing a second cleaning operation if the contamination level is less than or equal to the preset first reference value. The second cleaning operation includes cleaning the reflective surface by radiating atmospheric plasma onto the reflective surface and measuring a microcontamination level and a damage level of the reflective surface.

An extreme ultraviolet (EUV) collector inspection apparatus and method capable of precisely inspecting a contamination state of an EUV collector and EUV reflectance in accordance with the contamination state are provided. The EUV collector inspection apparatus includes a light source arranged in front of an EUV collector to be inspected and configured to output light in a visible light (VIS) band from UV rays, an optical device configured to output narrowband light from the light, and a camera configured to perform imaging from an UV band to a VIS band. An image by wavelength of the EUV collector is obtained by using the optical device and the camera and a contamination state of the EUV collector is inspected.

A collector transfers EUV illumination light from a radiation source region to illumination optics. Imaging optics of the collector image the radiation source region in a downstream focal region. The imaging optics are embodied so that the radiation source is imaged with at least one first imaging scale by the EUV illumination light, which is emitted with beam angles <20° between the radiation source region and the downstream focal region. The imaging optics are also embodied so that the radiation source is imaged with at least one second imaging scale by the illumination light emitted with beam angles >70°. The two imaging scales for the beam angles <20° on the one hand and >70° on the other hand differ by no more than a factor of 2.5. In addition to a corresponding collector, an illumination system contains field facets transfer optics.

An illumination system has illumination optics which guide EUV illumination light collected by a collector to an object field. The illumination optics have a field facet mirror and a pupil facet mirror. Pupil facets are part of transfer optics which image the field facets in a manner superposed on one another into the object field. The collector images a radiation source region into an intermediate focal region disposed downstream thereof. The latter constitutes the first image of the radiation source region in the beam path disposed downstream thereof. A constriction region not coinciding with the downstream focal region is situated between the collector and a first component of the illumination optics.

A radiation source contains a collector module comprising an optical collector, positioned in a vacuum chamber with an emitting plasma, further comprising a means for debris mitigation which include at least two casings arranged to output debris-free homocentric beams of the short-wavelength radiation, coming to the optical collector preferably consisting of several identical mirrors. Outside each casing there are permanent magnets that create a magnetic field inside the casings to mitigate charged fraction of debris particles and provide the debris-free homocentric beams of short-wavelength radiation. Other debris mitigating techniques are additionally used. Preferably the plasma is laser-produced plasma of a liquid metal target supplied by a rotating target assembly to a focus area of a laser beam. The technical result of the invention is the creation of high-powerful high-brightness debris-free sources of short-wavelength radiation with large, preferably more than 0.25 sr, collection solid angle.

A collector mirror for an EUV microlithography system. The collector mirror includes an optical grating having an optically effective mirror surface, which reflects electromagnetic used rays in an EUV spectral range emanating from a first focal point and focuses them onto a second focal point. The first and second focal points lie on a side of the optical grating facing the mirror surface and define an optical axis. The optical grating is configured, in interaction with a stop arranged at the second focal point, to allow the used rays to pass through the stop and to block electromagnetic remaining rays in a remaining spectral range different than the EUV spectral range. The optical grating includes a blazed grating composed of a plurality of mirror facets, each having a facet surface. The facet surfaces form the mirror surface of the blazed grating.

An EUV collector mirror has a reflection surface (16) to reflect usable EUV light which impinges on the reflection surface (16) from a source region (17) to a subsequent EUV optics. The reflection surface (16) carries a pump light grating structure (19) configured to retroreflect pump light (22) which impinges upon the pump light grating structure (19) from the source region (17) back to the source region (17). The pump light (22) has a wavelength deviating from the wavelength of the usable EUV light. Such EUV collector mirror enables a high conversion efficiency between the energy of pump light of a laser discharged produced plasma (LDPP) EUV light source on the one hand and the resulting usable EUV energy on the other.