A photomask mask assembly includes a reflective photomask and a protection structure. The reflective photomask includes a substrate and a reflective multilayer on a first substrate surface of the substrate at a front side of the reflective photomask. The protection structure is on a second substrate surface of the substrate at a backside of the reflective photomask, and is detachable from the reflective photomask at a temperature below 150 degree Celsius.

A method of preparing a metal mask substrate includes providing a metal substrate. Next, a gloss is measured and obtained from the surface of the metal substrate. Next, the gloss is determined whether to be within a predetermined range. When the gloss is determined within the predetermined range, a photolithography process is performed to the metal substrate, where the predetermined range is between 90 GU and 400 GU.

A method of preparing a metal mask substrate includes providing a metal substrate. Next, a gloss is measured and obtained from the surface of the metal substrate. Next, the gloss is determined whether to be within a predetermined range. When the gloss is determined within the predetermined range, a photolithography process is performed to the metal substrate, where the predetermined range is between 90 GU and 400 GU.

A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 μm. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.

A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 μm. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.

Collection reflectors with multiple reflector elements defined on a curved surface are used to collect EUV optical radiation from an EUV emitting area. Each of the reflector elements can image the emitting area at or near a corresponding reflective element of a second multi-element reflector that overlaps radiation from each of the multiple reflector element of the collection reflector to illuminate a grating reticle. Systems with such a collection reflector can use fewer optical elements. In addition, grating reticles are defined on a curve substrate an include a plurality of grating phase steps so that the grating reticle provides phase curvature along two axes but with physical curvature along a single axis. Methods of producing varying duty cycle 1D patterns are also disclosed.

Collection reflectors with multiple reflector elements defined on a curved surface are used to collect EUV optical radiation from an EUV emitting area. Each of the reflector elements can image the emitting area at or near a corresponding reflective element of a second multi-element reflector that overlaps radiation from each of the multiple reflector element of the collection reflector to illuminate a grating reticle. Systems with such a collection reflector can use fewer optical elements. In addition, grating reticles are defined on a curve substrate an include a plurality of grating phase steps so that the grating reticle provides phase curvature along two axes but with physical curvature along a single axis. Methods of producing varying duty cycle 1D patterns are also disclosed.

An object is to provide a mask blank

A mask blank having a substrate and a thin film, the substrate includes two main surfaces and a side surface with a chamfered surface provided between the two main surfaces and the side surface, one main surface of the two main surfaces includes an inner region including a center of the main surface and an outer peripheral region outside of the inner region, the thin film is provided on the inner region of the main surface, the surface reflectance Rs of the outer peripheral region with respect to light of 400 nm to 700 nm wavelength is 10% or less, and provided that Rf is the surface reflectance with respect to light of 400 nm to 700 nm wavelength in one section among sections of the thin film in the range of 9 nm to 10 nm film thickness, the contrast ratio (Rf/Rs) is 3.0 or more.

An object is to provide a mask blank

A mask blank having a substrate and a thin film, the substrate includes two main surfaces and a side surface with a chamfered surface provided between the two main surfaces and the side surface, one main surface of the two main surfaces includes an inner region including a center of the main surface and an outer peripheral region outside of the inner region, the thin film is provided on the inner region of the main surface, the surface reflectance Rs of the outer peripheral region with respect to light of 400 nm to 700 nm wavelength is 10% or less, and provided that Rf is the surface reflectance with respect to light of 400 nm to 700 nm wavelength in one section among sections of the thin film in the range of 9 nm to 10 nm film thickness, the contrast ratio (Rf/Rs) is 3.0 or more.

The present disclosure provides masks suitable for Extreme Ultraviolet (EUV) and X-ray lithography by including a non-reflective region combined with a reflective multilayer. This non-reflective region replaces a typical absorber layer used to provide the pattern for integrated circuits.