A digital exposure apparatus includes a lens array, the lens array at least including a first lens unit and a second lens unit, a light transposition assembly arranged on an exit light path of the second lens unit, and the light transposition assembly being used for controlling a light exiting from the second lens unit to be transposed with respect to an exposure direction of the digital exposure apparatus. When the digital exposure apparatus is used for exposure, a light passing through the first lens unit and a light penetrating through the second lens unit are needed to expose the same position for multiple times.

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 projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.

An exposure apparatus includes at least one radiation source, a plurality of projection lenses, and a lens switch. The radiation source is operable for providing a radiation beam. The lens switch is operable for selecting one of the projection lenses to focus the radiation beam to a target plane.

A method for manufacturing a membrane assembly for EUV lithography, the method including: providing a stack including: at least one membrane layer supported by a planar substrate, wherein the planar substrate has an inner region and a border region around the inner region; and a first sacrificial layer between the planar substrate and the membrane layer; selectively removing the inner region of the planar substrate such that the membrane assembly has: a membrane formed from the at least one membrane layer, and a border holding the membrane, the border having the border region of the planar substrate and the first sacrificial layer situated between the border region and the membrane layer, wherein the selectively removing the inner region of the planar substrate includes using an etchant which has a similar etch rate for the membrane layer and its oxide and a substantially different etch rate for the first sacrificial layer.

Disclosed is a metrology apparatus comprising an optical element configured to receive at or near a pupil plane of the metrology apparatus, at least first radiation comprising a first higher diffracted order and second radiation comprising a zeroth order resulting from illumination of a metrology target with radiation; and to direct said first radiation and second radiation together in a first direction. The metrology apparatus is further configured to form at least a first image of a first interference pattern, the first interference pattern resulting from interference of said first radiation and second radiation at an image plane.

A spatial light modulator imaging system is disclosed. The system comprises an illumination module configured to provide illumination light representing data patterns to be imaged by the spatial light modulator imaging system, a projection module configured to project the illumination light to a substrate, and an illumination-projection beam separator coupled between the illumination module and the projection module, where the illumination-projection beam separator is configured to receive the illumination light along an illumination optical axis and transmit the illumination light received to the projection module along a projection optical axis, and where the illumination optical axis and the projection optical axis are substantially parallel to each other.

Embodiments of the present disclosure provide a system and method for stabilizing optical lens temperatures, including detecting infrared radiation emitted from one or more optical lens, generating an infrared sensor signal based upon the detected infrared radiation, directing emission of light from one or more infrared light sources to the one or more optical lenses, and regulating the emission of the light from the one or more infrared light sources based on the infrared sensor signal for adjusting the temperature of the one or more optical lens.

A catadioptric projection objective has a first objective part, defining a first part of the optical axis and imaging an object field to form a first real intermediate image. It also has a second, catadioptric objective part forming a second real intermediate image using the radiation from the first objective part. The second objective part has a concave mirror and defines a second part of the optical axis. A third objective part images the second real intermediate image into the image plane and defines a third part of the optical axis. Folding mirrors deflect the radiation from the object plane towards the concave mirror; and deflect the radiation from the concave mirror towards the image plane. The first part of the optical axis defined by the first objective part is laterally offset from and aligned parallel with the third part of the optical axis.

A metrology tool, an aplanatic singlet lens, and a method of designing an aplanatic singlet lens are provided. The metrology tool is for determining a characteristic of a structure on a substrate. The metrology tool comprises an optical detection system for detecting radiation over a wavelength range. The optical detection system comprises an aplanatic singlet lens for focusing the radiation on to a detector. The aplanatic singlet lens has a n aplanatic wavelength which is within the wavelength range.