Optical assembly with coating and methods of use

A method, comprising:

• generating EUV radiation in an extreme ultraviolet (EUV) lithography system;
• passing the extreme ultraviolet radiation through a coating layer of a pellicle membrane;
• passing the extreme ultraviolet radiation that has passed through the coating layer through a transparent layer of the pellicle membrane, wherein the transparent layer of the pellicle membrane includes a matrix of a plurality of nanotube bundles, the plurality of nanotube bundles including nanotube bundles including nanotubes consisting of carbon atoms, nanotube bundles including nanotubes of carbon atoms and nitrogen atoms and nanotube bundles including nanotubes of carbon atoms and silicon atoms;
• reflecting the extreme ultraviolet radiation that has passed through the transparent layer from a mask;
• and
• receiving the extreme ultraviolet radiation, reflected by the mask, at a semiconductor substrate.