A glass substrate for EUVL includes a first main surface having a rectangular shape; a second main surface having a rectangular shape on an opposite side to the first main surface; four end surfaces orthogonal to the first and second main surfaces; four first chamfered surfaces formed on boundaries between the first main surface and the end surfaces; and four second chamfered surfaces formed on boundaries between the second main surface and the end surfaces. The glass substrate for EUVL is formed of quartz glass containing TiO.sub.2. The end surfaces include fluorine (F) and an element (A) other than fluorine that forms a gas cluster with fluorine, and satisfy relations:

S1=∫.sub.0.sup.x=50[nm]{D1(x)−(a1x+b1)}dx>0.2  (1)

S2=∫.sub.0.sup.x=50[nm]{D2(x)−(a2x+b2)}dx>0.03  (2)

A reflective mask blank includes a substrate and, disposed on or above the substrate in the following order from the substrate side, a reflective layer, a protective layer, and an absorbent layer. The reflective layer is a multilayered reflective film includes a plurality of cycles, each cycle including a high-refractive-index layer and a low-refractive-index layer. The reflective layer includes one phase inversion layer which is either the high-refractive-index layer or the low-refractive-index layer each having a film thickness increased by Δd ([unit: nm]). The increase in film thickness Δd [unit: nm] of the phase inversion layer satisfies a relationship: (¼+m/2)×13.53−1.0≤Δd≤(¼+m/2)×13.53+1.0. The reflective layer and the absorbent layer satisfy a relationship:

T.sub.abs+80 tanh(0.037N.sub.ML)−1.6 exp(−0.08N.sub.top)(N.sub.ML−N.sub.top).sup.2<140.

A reflective mask blank includes a substrate and, disposed on or above the substrate in the following order from the substrate side, a reflective layer, a protective layer, and an absorbent layer. The reflective layer is a multilayered reflective film includes a plurality of cycles, each cycle including a high-refractive-index layer and a low-refractive-index layer. The reflective layer includes one phase inversion layer which is either the high-refractive-index layer or the low-refractive-index layer each having a film thickness increased by Δd ([unit: nm]). The increase in film thickness Δd [unit: nm] of the phase inversion layer satisfies a relationship: (¼+m/2)×13.53−1.0≤Δd≤(¼+m/2)×13.53+1.0. The reflective layer and the absorbent layer satisfy a relationship:

T.sub.abs+80 tanh(0.037N.sub.ML)−1.6 exp(−0.08N.sub.top)(N.sub.ML−N.sub.top).sup.2<140.

Extreme ultraviolet (EUV) mask blanks, production systems therefor, and methods of reducing roughness are disclosed. The EUV mask blanks comprise a multilayer reflective stack on a substrate comprising a plurality of pairs of alternating layers comprising a first layer and a second layer, the first layer including a first element selected from the group consisting of Si, B, Al, Mg, Zr, Ba, Nb, Ti, Gd, Y, and Ca; and the second layer including a second element selected from the group consisting of Ru, Mo, Ta, Sb, Tc, Nb, Ir, Pt, and Pd. Some EUV mask blanks described herein include interface layer between the first layer and the second layer, the interface layer including an interface element selected from the group consisting of Si, B, C, Al, Mo, and Ru.

The invention relates to a method and an apparatus for repairing at least one defect of a photolithographic mask for the extreme ultraviolet (EUV) wavelength range, wherein the method includes the steps of: (a) determining the at least one defect; and (b) ascertaining a repair shape for the at least one defect; (c) wherein the repair shape is diffraction-based in order to take account of a phase disturbance by the at least one defect.

The invention relates to a method and an apparatus for repairing at least one defect of a photolithographic mask for the extreme ultraviolet (EUV) wavelength range, wherein the method includes the steps of: (a) determining the at least one defect; and (b) ascertaining a repair shape for the at least one defect; (c) wherein the repair shape is diffraction-based in order to take account of a phase disturbance by the at least one defect.

Extreme ultraviolet (EUV) mask blanks, methods for their manufacture and production systems therefor are disclosed. The EUV mask blanks comprise a multilayer stack of absorber layers on the capping layer, the multilayer stack of absorber layers including a plurality of absorber layer pairs.

A reflective film coated substrate includes a substrate having two main surfaces opposite to each other and end faces connected to outer edges of the two main surfaces; and a reflective film formed on one of the main surfaces and extending onto at least part of the end faces. The reflective film on the main surface has a multilayer structure including low refractive index layers and high refractive index layers alternately formed. The reflective film which extends onto the end faces has a single-layer structure containing a first element higher in content than any other element in the low refractive index layers and a second element higher in content than any other element in the high refractive index layers.

A reticle is provided. The reticle includes a first reflective multilayer (ML) over a mask substrate and a capping layer over the first reflective ML. The reticle also includes a first absorption layer over the capping layer and a second reflective multilayer (ML) over the first absorption layer. The reticle further includes an etch stop layer over the second reflective ML and a third reflective multilayer (ML) over the etch stop layer. In addition, the reticle includes an absorption film pair over the third reflective ML.

A reticle is provided. The reticle includes a first reflective multilayer (ML) over a mask substrate and a capping layer over the first reflective ML. The reticle also includes a first absorption layer over the capping layer and a second reflective multilayer (ML) over the first absorption layer. The reticle further includes an etch stop layer over the second reflective ML and a third reflective multilayer (ML) over the etch stop layer. In addition, the reticle includes an absorption film pair over the third reflective ML.