An optical element and a lithographic apparatus including the optical element. The optical element includes a first member having a curved optical surface and a heat transfer surface, and a second member that comprises at least one recess, the at least one recess sealed against the heat transfer surface to form at least one closed channel between the first member and the second member to allow fluid to flow therethrough for thermal conditioning of the curved optical surface. In an embodiment, one or more regions of the heat transfer surface exposed to the at least one closed channel are positioned along a curved profile similar to that of the curved optical surface.

A method of making a mirror for use with extreme ultraviolet (EUV) or X-ray radiation is disclosed. The method includes: a) providing an optical element having a curved mirror surface, wherein the curved mirror surface comprises localized defects that degrade performance of the curved mirror surface; b) spin-coating the curved mirror surface with a material to cover at least some of the defects; and c) curing the spin-coated material on the curved mirror surface to reduce the number of defects and improve the performance of the curved mirror surface. Also disclosed is a mirror made by the method.

A lithography system includes an extreme ultraviolet (EUV) light source, a reticle stage, a reflection layer, and a plurality of light permeable protrusions. The EUV light source is configured for generating an EUV light beam. The reticle stage is configured for holding a reticle with a front surface of the reticle facing in a downward direction. The reflection layer is below the reticle stage. The light permeable protrusions are formed on the reflection layer. Each of the light permeable protrusions includes a bouncing surface facing in a direction that forms an acute angle with the downward direction. A first portion of the EUV light beam from the EUV light source passes through the bouncing surface of each of the light permeable protrusions to the reflection layer and is reflected to the reticle by the reflection layer.

A microlithographic projection exposure apparatus comprises a projection lens for projecting structures of a mask into a substrate plane via exposure radiation. At least one optical element of the projection lens is provided with a manipulator configured for the targeted input of thermal energy into the optical element, without one of further optical elements of the projection lens being significantly heated in the process. The projection exposure apparatus furthermore comprises a control device configured for controlling the exposure radiation and for controlling the manipulator so that an effect on an optical property of the projection lens that is caused by a decrease in a thermal energy input into the projection lens due to an exposure pause is at least partly compensated for by the energy input via the manipulator. Furthermore, the disclosure relates to a corresponding method for controlling a microlithographic projection exposure apparatus.

An assembly, for example in a microlithographic projection exposure apparatus, comprises an optical element and a joint arrangement for mechanically bearing the optical element. The joint arrangement comprises at least one connecting element secured on the optical element. The mass of the connecting element is distributed over its length so that the moment of inertia of the connecting element is increased in comparison with a connecting element of identical mass and length in which the mass is distributed uniformly over the length.

An amorphous layer is used as a protective coating for hygroscopic nonlinear optical crystals. The amorphous layer consists of one or more alkali metal borates and/or alkali earth metal borates. The amorphous layer slows or prevents water and/or oxygen from diffusing into the hygroscopic nonlinear optical crystal, thus simplifying handling, storage and operating environmental requirements. One or multiple additional coating layers may be placed on top of the amorphous layer, with the additional coating layers including conventional optical materials. The thicknesses of the amorphous layer and/or additional layers may be chosen to reduce reflectance of the optical component at one or more specific wavelengths. The coated nonlinear optical crystal is used in an illumination source utilized in a semiconductor inspection system, a metrology system, or a lithography system.

An assembly including a non-linear element configured for generating broadband radiation from input radiation coupled into the non-linear element. The assembly further includes an optical element positioned downstream of the non-linear element configured to reflect a fraction of the broadband radiation back into the non-linear element. The non-linear element can be a nonlinear fiber, such as a hollow-core photonic crystal fiber (HC-PCF).

A micromirror array includes a substrate, a plurality of mirrors for reflecting incident radiation, and for each mirror of the plurality of mirrors, a respective post connecting the substrate to the respective mirror. The micromirror array further includes, for each mirror of the plurality of mirrors, one or more electrostatic actuators connected to the substrate for applying force to the respective post to displace the respective post relative to the substrate, thereby displacing the respective mirror. Also disclosed is a method of forming such a micromirror array. The micromirror array may be used in a programmable illuminator. The programmable illuminator may be used in a lithographic apparatus and/or in an inspection apparatus.

An overlay pattern includes a light-transmitting region and a first light-proof region. The first light-proof region and the light-transmitting region are arranged on a same plane, and an area of the first light-proof region is larger than an area of the light-transmitting region. An orthographic projection of the first light-proof region on the plane and an orthographic projection of the light-transmitting region on the plane do not overlap and form a first rectangular region.

A mirror structure includes an insulator layer and a first conductive layer disposed on the insulator layer. The first conductive layer includes a first non-conductive film disposed on the insulator layer. The first non-conductive film includes one or more first conductive segments. The mirror structure also includes a reflective layer disposed on the first conductive layer and an electro optical layer disposed on the reflective layer. The mirror structure further includes a second conductive layer disposed on the electro optical layer. The second conductive layer includes a second non-conductive film disposed on the electro optical layer. The second non-conductive film includes one or more second conductive segments.