极紫外多层膜残余应力初步研究

 针对极紫外多层膜在激光等离子体诊断、极紫外光刻等方面的应用，进行了Mo/Si多层膜残余应力的实验研究，讨论了多层膜残余应力的成因。实验结果表明：Mo单层膜表现为张应力， Si单层膜表现为压应力；通过传统方法制备的13.0 nm处高反射率的40对Mo/Si多层膜会产生-500 MPa左右的压应力，其压应力主要是由膜层之间的贯穿扩散引起的；通过改变膜层比率可以在一定程度上补偿因贯穿扩散产生的压应力，但是以牺牲多层膜反射率为代价。

Control of residual stress in extreme ultraviolet multilayer coatings

Study of stress in Mo/Si multilayers is carried out for application of extreme ultraviolet multilayer coatings in the diagnosis of high density plasmas and extreme ultraviolet lithography. Stress generating mechanisms is discussed. Precise measurement of stress is taken by ZYGO interferometer. It is observed that the growth of the Mo component in the multilayers is tensile, while that of the Si component is compressive. The residual stress in a 40-bilayer Mo/Si multilayer coating with high reflectivity is -500 MPa (compressive), stress generation may be attributed to the interfacial diffusion. By varying Mo-to Si thickness ratio(Γ), the stress in multilayers can be compensated to a certain extent. However, the reflectance of Mo/Si multilayers is reduced correspondently.