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

A photolithographic mask assembly according to the present disclosure accompanies a photolithographic mask. The photolithographic mask includes a capping layer over a substrate and an absorber layer disposed over the capping layer. The absorber layer includes a first main feature area, a second main feature area, and a venting feature area disposed between the first main feature area and the second main feature area. The venting feature area includes a plurality of venting features.

A photolithographic mask assembly according to the present disclosure accompanies a photolithographic mask. The photolithographic mask includes a capping layer over a substrate and an absorber layer disposed over the capping layer. The absorber layer includes a first main feature area, a second main feature area, and a venting feature area disposed between the first main feature area and the second main feature area. The venting feature area includes a plurality of venting features.

A portion of a buffer layer on a backside of a substrate of a photomask assembly may be removed prior to formation of one or more capping layers on the backside of the substrate. The one or more capping layers may be formed directly on the backside of the substrate where the buffer layer is removed from the substrate, and a hard mask layer may be formed directly on the one or more capping layers. The one or more capping layers may include a low-stress material to promote adhesion between the one or more capping layers and the substrate, and to reduce and/or minimize peeling and delamination of the capping layer(s) from the substrate. This may reduce the likelihood of damage to the pellicle layer and/or other components of the photomask assembly and/or may increase the yield of an exposure process in which the photomask assembly is used.

A portion of a buffer layer on a backside of a substrate of a photomask assembly may be removed prior to formation of one or more capping layers on the backside of the substrate. The one or more capping layers may be formed directly on the backside of the substrate where the buffer layer is removed from the substrate, and a hard mask layer may be formed directly on the one or more capping layers. The one or more capping layers may include a low-stress material to promote adhesion between the one or more capping layers and the substrate, and to reduce and/or minimize peeling and delamination of the capping layer(s) from the substrate. This may reduce the likelihood of damage to the pellicle layer and/or other components of the photomask assembly and/or may increase the yield of an exposure process in which the photomask assembly is used.

Disclosed is a pellicle for extreme ultraviolet (EUV) lithography and a method of manufacturing the same. The pellicle for EUV lithography includes a pellicle membrane including a plurality of through holes. The pellicle membrane includes a core layer and a protective layer that covers and protects the core layer. The frame supports the pellicle membrane.

Disclosed is a pellicle for extreme ultraviolet (EUV) lithography and a method of manufacturing the same. The pellicle for EUV lithography includes a pellicle membrane including a plurality of through holes. The pellicle membrane includes a core layer and a protective layer that covers and protects the core layer. The frame supports the pellicle membrane.

A method for removing particles includes receiving a pellicle including a pellicle membrane, a pellicle frame and at least a particle disposed on the pellicle membrane, generating light beams to form an optical trap extending in a direction perpendicular to the pellicle membrane, and removing the particle from the pellicle membrane by the optical trap.

A method for removing particles includes receiving a pellicle including a pellicle membrane, a pellicle frame and at least a particle disposed on the pellicle membrane, generating light beams to form an optical trap extending in a direction perpendicular to the pellicle membrane, and removing the particle from the pellicle membrane by the optical trap.

A technique that can achieve a pellicle film made of carbon nanotubes and having high in-plane transmittance uniformity. The pellicle film contains a plurality of first carbon nanotubes extending in a first direction and arrayed in the radial direction, and a plurality of second carbon nanotubes extending in a second direction intersecting the first direction, and arrayed in their radial direction.