A reflective mask blank including a substrate, a multilayer reflection film formed on one main surface of the substrate and reflects exposure light. The multilayer reflection film has a periodically laminated structure portion in which low refractive index layers and high refractive index layers are alternately laminated, and at least one of the low refractive index layer has a two-layered structure consisting of one layer containing molybdenum, and at least one additive element selected from the group consisting of nitrogen, carbon, boron, silicon and hydrogen, and the other layer containing molybdenum and substantively free of other elements other than molybdenum.

A photomask blank having a substrate; and a multilayer film including a first layer, a second layer, and a third layer. The first layer contains 43 at % or less chromium, 32 at % or more oxygen, 25 at % or less nitrogen and 5 at % or more and 18 at % or less carbon and has a thickness of 8 nm or more and 16 nm or less. The second layer contains 66 at % or more and 92 at % or less chromium and 8 at % or more and 30 at % or less nitrogen and has a thickness of 50 nm or more and 75 nm or less. The third layer contains 44 at % or less chromium, 30 at % or more oxygen and 28 at % or less nitrogen and has a thickness of 10 nm or less. A surface roughness Rq of the multilayer film is 0.65 nm or less.

A photomask blank having a substrate; and a multilayer film including a first layer, a second layer, and a third layer. The first layer contains 43 at % or less chromium, 32 at % or more oxygen, 25 at % or less nitrogen and 5 at % or more and 18 at % or less carbon and has a thickness of 8 nm or more and 16 nm or less. The second layer contains 66 at % or more and 92 at % or less chromium and 8 at % or more and 30 at % or less nitrogen and has a thickness of 50 nm or more and 75 nm or less. The third layer contains 44 at % or less chromium, 30 at % or more oxygen and 28 at % or less nitrogen and has a thickness of 10 nm or less. A surface roughness Rq of the multilayer film is 0.65 nm or less.

A photolithography method is provided. The photolithography method includes forming a photoresist layer on a wafer, exposing a portion of the photoresist layer by using an exposure device and a mask, and forming a photoresist pattern by removing a non-exposed portion of the photoresist layer. The mask includes a substrate having a main pattern area and a blocking area outside the main pattern area, a main pattern on the main pattern area of the substrate, and a blocking pattern on the blocking area of the substrate. An external circumference of the blocking pattern extends to the maximum area of the mask that may be illuminated by the exposure device or to the outside of the maximum area of the mask.

A photolithography method is provided. The photolithography method includes forming a photoresist layer on a wafer, exposing a portion of the photoresist layer by using an exposure device and a mask, and forming a photoresist pattern by removing a non-exposed portion of the photoresist layer. The mask includes a substrate having a main pattern area and a blocking area outside the main pattern area, a main pattern on the main pattern area of the substrate, and a blocking pattern on the blocking area of the substrate. An external circumference of the blocking pattern extends to the maximum area of the mask that may be illuminated by the exposure device or to the outside of the maximum area of the mask.

A lithography exposure system includes a light source, a substrate stage, and a mask stage between the light source and the substrate stage along an optical path from the light source to the substrate stage. The lithography exposure system further comprises a reflector along the optical path. The reflector comprises: a first layer having a first material and a first thickness; a second layer having the first material and a second thickness different from the first thickness; and a third layer between the first layer and the second layer, and having a second material different from the first material.

An EUV reflective structure includes a substrate and multiple pairs of a Si layer and a Mo layer. The Si layer includes a plurality of cavities.

Methods for the manufacture of extreme ultraviolet (EUV) mask blanks and production systems therefor are disclosed. A method for forming an EUV mask blank comprises forming a bilayer on a portion of a multi-cathode PVD chamber interior and then forming a multilayer stack of Si/Mo on a substrate in the multi-cathode PVD chamber.

A substrate with a multilayer reflective film capable of facilitating the discovery of contaminants, scratches and other critical defects by inhibiting the detection of pseudo defects attributable to surface roughness of a substrate or film in a defect inspection using a highly sensitive defect inspection apparatus. The substrate with a multilayer reflective film has a multilayer reflective film obtained by alternately laminating a high refractive index layer and a low refractive index layer on a main surface of a mask blank substrate used in lithography, wherein an integrated value I of the power spectrum density (PSD) at a spatial frequency of 1 μm.sup.−1 to 10 μm.sup.−1 of the surface of the substrate with a multilayer reflective film, obtained by measuring a region measuring 3 μm×3 μm with an atomic force microscope, is not more than 180×10.sup.−3 nm.sup.3, and the maximum value of the power spectrum density (PSD) at a spatial frequency of 1 μm.sup.−1 to 10 μm.sup.−1 is not more than 50 nm.sup.4.

A substrate with a multilayer reflective film capable of facilitating the discovery of contaminants, scratches and other critical defects by inhibiting the detection of pseudo defects attributable to surface roughness of a substrate or film in a defect inspection using a highly sensitive defect inspection apparatus. The substrate with a multilayer reflective film has a multilayer reflective film obtained by alternately laminating a high refractive index layer and a low refractive index layer on a main surface of a mask blank substrate used in lithography, wherein an integrated value I of the power spectrum density (PSD) at a spatial frequency of 1 μm.sup.−1 to 10 μm.sup.−1 of the surface of the substrate with a multilayer reflective film, obtained by measuring a region measuring 3 μm×3 μm with an atomic force microscope, is not more than 180×10.sup.−3 nm.sup.3, and the maximum value of the power spectrum density (PSD) at a spatial frequency of 1 μm.sup.−1 to 10 μm.sup.−1 is not more than 50 nm.sup.4.