Multi-layer film material, extreme ultraviolet light reflector and preparation method and application of multi-layer film material and extreme ultraviolet light reflector

The invention belongs to the technical field of extreme ultraviolet optical elements, and particularly relates to a multilayer film material, an extreme ultraviolet reflector and a preparation method and application of the extreme ultraviolet reflector. The multilayer film material provided by the invention comprises a first periodic unit or a second periodic unit which are stacked, the first periodic unit comprises an Nb layer, a Y layer and a Si layer which are stacked in sequence, and the second periodic unit comprises an Nb layer, a first Y layer, a Si layer and a second Y layer which are stacked in sequence; when the multi-layer film material is a stacked first periodic unit, the two surfaces of the multi-layer film material are an Nb layer and an Si layer respectively; and when the multi-layer film material is a stacked second periodic unit, the two surfaces of the multi-layer film material are an Nb layer and a second Y layer respectively. The Y layer is added between the Nb layer and the Si layer, so