Extreme ultraviolet (EUV) mask blanks, methods for their manufacture and production systems therefor are disclosed. The EUV mask blanks comprise a substrate having a first side and a second side; a backside coating layer comprising an alloy of tantalum and nickel on the first side of the substrate; a multilayer stack of reflective layers on the second side of the substrate, the multilayer stack of reflective layers including a plurality of reflective layers including reflective layer pairs; a capping layer on the multilayer stack of reflecting layers; and an absorber layer on the capping layer.

In a method of manufacturing a photo mask, an etching mask layer having circuit patterns is formed over a target layer of the photo mask to be etched. The photo mask includes a backside conductive layer. The target layer is etched by plasma etching, while preventing active species of plasma from attacking the backside conductive layer.

A substrate with an electrically conductive film for fabricating a reflective mask is obtained that is capable of preventing positional shift of the reflective mask during pattern transfer. Provided is a substrate with an electrically conductive film used in lithography, the substrate with an electrically conductive film having an electrically conductive film formed on one of the main surfaces of a mask blank substrate, and a coefficient of static friction of the surface of the electrically conductive film is not less than 0.25.

A substrate with an electrically conductive film for fabricating a reflective mask is obtained that is capable of preventing positional shift of the reflective mask during pattern transfer. Provided is a substrate with an electrically conductive film used in lithography, the substrate with an electrically conductive film having an electrically conductive film formed on one of the main surfaces of a mask blank substrate, and a coefficient of static friction of the surface of the electrically conductive film is not less than 0.25.

In an embodiment, a photomask includes: a substrate over a first conductive layer, the substrate formed of a low thermal expansion material (LTEM); a second conductive layer over the first conductive layer; a reflective film stack over the substrate; a capping layer over the reflective film stack; an absorption layer over the capping layer; and an antireflection (ARC) layer over the absorption layer, where the ARC layer and the absorption layer have a plurality of openings in a first region exposing the capping layer, where the ARC layer, the absorption layer, the capping layer, and the reflective film stack have a trench in a second region exposing the second conductive layer.

A reflective mask blank for EUV lithography, includes: a substrate; a conductive film; a reflective layer; and an absorption layer, the absorption layer absorbing the EUV light, wherein the conductive film has a refractive index n.sub.?1000-1100 nm of 5.300 or less and has an extinction coefficient k.sub.?1000-1100 nm of 5.200 or less, at a wavelength of 1000 nm to 1100 nm, the conductive film has a refractive index n.sub.?600-700 nm of 4.300 or less and has an extinction coefficient k.sub.?600-700 nm of 4.500 or less, at a wavelength of 600 nm to 700 nm, the conductive film has a refractive index n.sub.?400-500 nm of 2.500 or more and has an extinction coefficient k.sub.?400-500 nm of 0.440 or more, at a wavelength of 400 nm to 500 nm, and the conductive film has a film thickness t of 40 nm to 350 nm.

Provided is a substrate with conductive film for fabricating a reflective mask capable of correcting misalignment of the reflective mask from the back surface with a laser beam and the like. The substrate with conductive film is formed in which a conductive film is formed on one of the main surfaces of a mask blank substrate used in lithography, wherein an intermediate layer having a stress adjustment function is provided between the substrate and the conductive film, and transmittance of a laminated film including the intermediate layer and the conductive film for light having a wavelength of 532 nm is not less than 20%.

This conductive composition includes: a conductive polymer (a) having a sulfonic acid group and/or a carboxy group; a basic compound (b) having at least one nitrogen-containing heterocyclic ring and an amino group; an aqueous polymer (c) having a hydroxyl group (excluding the conductive polymer (a)); a hydrophilic organic solvent (d); and water (e).

This conductive composition includes: a conductive polymer (a) having a sulfonic acid group and/or a carboxy group; a basic compound (b) having at least one nitrogen-containing heterocyclic ring and an amino group; an aqueous polymer (c) having a hydroxyl group (excluding the conductive polymer (a)); a hydrophilic organic solvent (d); and water (e).

In an embodiment, a photomask includes: a substrate over a first conductive layer, the substrate formed of a low thermal expansion material (LTEM); a second conductive layer over the first conductive layer; a reflective film stack over the substrate; a capping layer over the reflective film stack; an absorption layer over the capping layer; and an antireflection (ARC) layer over the absorption layer, where the ARC layer and the absorption layer have a plurality of openings in a first region exposing the capping layer, where the ARC layer, the absorption layer, the capping layer, and the reflective film stack have a trench in a second region exposing the second conductive layer.