A filtration formed nanostructure pellicle film is disclosed. The filtration formed nanostructure pellicle film includes a plurality of carbon nanofibers that are intersected randomly to form an interconnected network structure in a planar orientation. The interconnected structure allows for a high minimum EUV transmission rate of at least 92%, with a thickness ranging from a lower limit of 3 nm to an upper limit of 100 nm, to allow for effective EUV lithography processing.

The present invention is to provide a pellicle frame in a frame shape, having an upper end face to arrange a pellicle film thereon and a lower end face to face a photomask, and which is characterized by being provided with a notched part from an outer side face toward an inner side face of the upper end face, and to provide a pellicle characterized by including the pellicle frame as a component.

The present invention is to provide a pellicle frame in a frame shape, having an upper end face to arrange a pellicle film thereon and a lower end face to face a photomask, and which is characterized by being provided with a notched part from an outer side face toward an inner side face of the upper end face, and to provide a pellicle characterized by including the pellicle frame as a component.

The present invention provides a lightweight optical member that can be produced at a relatively low cost, wherein distortion due to temperature rise is suppressed, and the appearance color is sufficiently blackened or darkened, and a method for efficiently producing the optical member. The optical member of the present invention comprises: a base member made of titanium or a titanium alloy, and a carbon-doped titanium oxide layer formed on the surface of the base member. The carbon content in the carbon-doped titanium oxide layer is preferably 0.1 to 15 at %.

The present invention provides a lightweight optical member that can be produced at a relatively low cost, wherein distortion due to temperature rise is suppressed, and the appearance color is sufficiently blackened or darkened, and a method for efficiently producing the optical member. The optical member of the present invention comprises: a base member made of titanium or a titanium alloy, and a carbon-doped titanium oxide layer formed on the surface of the base member. The carbon content in the carbon-doped titanium oxide layer is preferably 0.1 to 15 at %.

A method of removing a pellicle from a photomask includes removing a portion of a membrane from a pellicle frame, wherein the pellicle frame remains attached to the photomask following the removing of the portion of the membrane. The method further includes removing the pellicle frame from the photomask. The method further includes cleaning the photomask.

A method of removing a pellicle from a photomask includes removing a portion of a membrane from a pellicle frame, wherein the pellicle frame remains attached to the photomask following the removing of the portion of the membrane. The method further includes removing the pellicle frame from the photomask. The method further includes cleaning the photomask.

A method for manufacturing a membrane assembly for EUV lithography, the method including: providing a stack having a planar substrate and at least one membrane layer, wherein the planar substrate includes an inner region and a border region around the inner region; and selectively removing the inner region of the planar substrate. The membrane assembly includes: a membrane formed from the at least one membrane layer; and a border holding the membrane, the border formed from the border region of the planar substrate. The stack is provided with a mechanical protection material configured to mechanically protect the border region during the selectively removing the inner region of the planar substrate.

A method for manufacturing a membrane assembly for EUV lithography, the method including: providing a stack having a planar substrate and at least one membrane layer, wherein the planar substrate includes an inner region and a border region around the inner region; and selectively removing the inner region of the planar substrate. The membrane assembly includes: a membrane formed from the at least one membrane layer; and a border holding the membrane, the border formed from the border region of the planar substrate. The stack is provided with a mechanical protection material configured to mechanically protect the border region during the selectively removing the inner region of the planar substrate.

A pellicle for EUV exposure that has a high transmittance to EUV light, causes little outgassing, and is not much contaminated, and a method for manufacturing the same are provided. A pellicle (100) includes a pellicle film (101); a support frame (103); and a first adhesive layer (109) provided at an end of the support frame, the end being opposite to an end on which the pellicle film is extended. The pellicle further includes an inorganic layer (111) on a side surface of the first adhesive layer, the side surface extending in a direction crossing a surface of the pellicle film, and the pellicle film being extended on the side surface. The inorganic layer has a mass absorption coefficient (μ.sub.m) in the range of 5×10.sup.3 cm.sup.2/g to 2×10.sup.5 cm2/g.