An apparatus for generating extreme ultraviolet (EUV) light includes a raw material supply unit supplying a plasma source for generating EUV light. An EUV light source unit uses a laser to generate plasma from the plasma source. A filter is configured to extract EUV light from the light. A first protective layer is disposed on a front surface of the filter. A frame having a first region exposing at least a portion of the filter or the first protective layer is disposed on the first protective layer. A width of the first region is smaller than a width of the first protective layer and smaller than or equal to a width of the filter.

Disclosed are a photomask, an exposure apparatus, and a method of fabricating a three-dimensional semiconductor memory device using the same. The photomask may include a mask substrate, a first mask pattern on the mask substrate, and an optical path modulation substrate. The optical path modulation substrate may include a first region on a portion of the first mask pattern, and a second region on another portion of the first mask pattern. The second region has a thickness that is less than a thickness of the first region.

A lithographic apparatus has: a conduit through which a gas can flow; a gas mover configured to cause the gas to flow in the conduit; a wall in contact with the gas in the conduit and defining a membrane aperture therein; and an acoustic filter including a flexible membrane fixed in the membrane aperture. The acoustic filter reduces transmission of acoustic disturbances without adding any flow resistance.

An apparatus (e.g., a multi-spectral optical filter array, an optical wafer, an optical component) has an aperture mask printed directly thereon, the aperture mask including a positive or negative photoresist. The apparatus includes a substrate having the aperture mask printed on at least one of a light entrance surface or a light exit surface of the substrate so as to provide an aperture over a portion of the substrate. The photoresist from which the aperture mask is formed is photo-definable or non-photo-definable, and is deposited/printed to form the aperture mask on the substrate.

A diffractive optical element may include sub-wavelength period stack-and-gap structured layers providing transmissive phase delay at a wavelength. The sub-wavelength period stack-and-gap structured layers may include a set of thin anti-reflection layers that are index matched to an environment or a substrate over a range of fill factors of the sub-wavelength period.

A projection exposure method for exposing a radiation-sensitive substrate with at least one image of a pattern of a mask is provided in which an illumination field of the mask is illuminated by illumination radiation with an operating wavelength λ that was provided by an illumination system.

A method and a device for characterizing a mask for microlithography in a characterization process carried out using an optical system, wherein the optical system includes an illumination optical unit and an imaging optical unit and wherein in the characterization process structures of the mask are illuminated by the illumination optical unit, the mask is imaged onto a detector unit by the imaging optical unit and image data recorded by the detector unit are evaluated in an evaluation unit. A method includes the following steps: determining a temporal variation of at least one variable that is characteristic of the thermal state of the optical system, and modifying the characterization process depending on the temporal variation determined.

A projection exposure method and apparatus are disclosed for exposing a radiation-sensitive substrate with at least one image of a pattern of a mask under the control of an operating control system of a projection exposure apparatus, part of the pattern lying in an illumination region is imaged onto the image field on the substrate with the aid of a projection lens, wherein all rays of the projection radiation contributing to the image generation in the image field form a projection beam path.

A radiation filter for reducing transmission of an unwanted wavelength of radiation. The radiation filter includes zirconium and SiN.sub.3. The radiation filter may form part of a radiation sensor including a passivation layer arranged to receive radiation transmitted by the radiation filter, a photodiode arranged to receive radiation transmitted by the passivation layer, and circuit elements connected to the photodiode. The radiation sensor may perform optical measurements as part of an extreme ultraviolet lithographic apparatus or a lithographic tool.

Provided are a method of forming a mask, the method accurately and quickly restoring an image on the mask to the shape on the mask, and a mask manufacturing method using the method of forming the mask. The method of forming a mask includes obtaining first images by performing rasterization and image correction on shapes on the mask corresponding to first patterns on a wafer, obtaining second images by applying a transformation to the shapes on the mask, performing deep learning based on a transformation relationship between ones of the first images and ones of the second images corresponding to the first images, and forming a target shape on the mask corresponding to a target pattern on the wafer, based on the deep learning. The mask is manufactured based on the target shape on the mask.