▎ 摘　　要

NOVELTY - The method involves subjecting a metal substrate to a process, which forms ribs on the metal substrate. The ribs are formed by depositing a resist onto the substrate. A lithographic process is performed to transfer a pattern corresponding to the ribs into the resist. The resist and etching away portions of the metal substrate, which do not form the ribs, are etched. The ribs are orientated with respect to orientation of the crystalline structure of the metal such that the ribs exhibit desired physical and chemical properties. USE - Method for forming a film of graphene used as a pellicle and a spectral purity filter in a lithographic apparatus i.e. extreme UV lithographic apparatus. ADVANTAGE - The method enables allowing a number of layers of graphene which form the graphene film and dimensions of the graphene film to be controlled. The method enables producing the graphene film, which includes little or no defects that can cause the transmittance of the graphene film to be inhomogeneous. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a metal catalyst preparation method.