A pellicle for an EUV photo mask includes a first layer; a second layer; and a main layer disposed between the first layer and second layer and including a plurality of nanotubes. At least one of the first layer or the second layer includes a two-dimensional material in which one or more two-dimensional layers are stacked. In one or more of the foregoing and following embodiments, the first layer includes a first two-dimensional material and the second layer includes a second two-dimensional material.

A pellicle for an EUV photo mask includes a first layer; a second layer; and a main layer disposed between the first layer and second layer and including a plurality of nanotubes. At least one of the first layer or the second layer includes a two-dimensional material in which one or more two-dimensional layers are stacked. In one or more of the foregoing and following embodiments, the first layer includes a first two-dimensional material and the second layer includes a second two-dimensional material.

There is provided an EUV transmissive membrane including: a main layer composed of metallic beryllium that has a first surface and a second surface; and a pair of surface layers provided on the first surface and the second surface of the main layer, each containing at least one fluoride selected from beryllium fluoride, beryllium fluoride nitride, beryllium fluoride oxide, and beryllium fluoride nitride oxide.

There is provided an EUV transmissive membrane including: a main layer composed of metallic beryllium that has a first surface and a second surface; and a pair of surface layers provided on the first surface and the second surface of the main layer, each containing at least one fluoride selected from beryllium fluoride, beryllium fluoride nitride, beryllium fluoride oxide, and beryllium fluoride nitride oxide.

In a method of cleaning a photo mask, the photo mask is placed on a support such that a pattered surface faces down, and an adhesive sheet is applied to edges of a backside surface of the photo mask.

In a method of cleaning a photo mask, the photo mask is placed on a support such that a pattered surface faces down, and an adhesive sheet is applied to edges of a backside surface of the photo mask.

A quartz glass plate has a quartz glass plate body and a quartz glass member adhered to the quartz glass plate body through an adhesive layer, where the adhesive layer contains silica, and a sum of concentrations of Li, Na, and K ions, being alkali metal ions and Ca ions, being alkaline earth metal ions contained in the adhesive layer is 10 ppm by mass or less. Consequently, a step with a uniform thickness can be formed, and a quartz glass plate is not easily damaged by irradiation with a light containing an ultraviolet ray.

A quartz glass plate has a quartz glass plate body and a quartz glass member adhered to the quartz glass plate body through an adhesive layer, where the adhesive layer contains silica, and a sum of concentrations of Li, Na, and K ions, being alkali metal ions and Ca ions, being alkaline earth metal ions contained in the adhesive layer is 10 ppm by mass or less. Consequently, a step with a uniform thickness can be formed, and a quartz glass plate is not easily damaged by irradiation with a light containing an ultraviolet ray.

A pellicle for extreme ultraviolet (EUV) lithography is based on yttrium carbide and used in a EUV lithography process. The pellicle for EUV lithography includes a pellicle layer that has a core layer containing yttrium carbide. The yttrium carbide is YC.sub.x in which the atomic percentage of carbon is within a range of 25% to 45%.

A first capping layer is deposited over a substrate. A network of nanowires is grown over the first capping layer. A second capping layer is deposited over the network of nanowires. The substrate is etched to form a frame of a pellicle. The first capping layer and the second capping layer are patterned to form a membrane of the pellicle, wherein the patterning reduces a material of the first capping layer and the second capping layer to form a coating on the nanowires.