中心波长为13．9nm的正入射Mo／Si多层膜

Normal-Incidence Reflectivity of Mo/Si Multilayer at 13.9 nm

用由铜靶激光等离子体光源等组成的反射率计对自行设计的周期厚度为7.14nm的120层Mo/Si多层膜进行极紫外(EUV)波段反射率测量。由于多层膜层数增加所引起的吸收、膜层界面之间的扩散以及镀膜过程中的膜厚控制误差或表面被氧化(污染)等原因,正入射Mo/Si多层膜在13.9nm处的反射率低于理论计算值73.2%,最后用原子力显微镜(AFM)测量其表面粗糙度为σ=0.401nm。

The results of the reflectivity measurement of a laser-produced plasma （LPP） source of extreme ultraviolet （EUV） for 13.9 nm are presented. The designed structure with 120 layers of molybdenum/silicon （Mo/Si） muhilayer and a period thickness of 7.14 nm was produced by ion beam sputter deposition technique. Because of the absorption by the increase overall thickness, diffusion between layers and surface oxidation （contamination）, adjacent normal-incidence, the reflectivity of muhilayer at 13.9 nm remains below the theoretical value of 73.2%. The surface roughness of multilayer measured by atom force microscope （AFM） is 0. 401 nm.