極紫外光多層膜反射鏡的反射率是極紫外光微影蝕刻技術中決定產能的重要參數。然而組成 EUV 多層膜反射鏡的兩材料 Mo 和 Si 傾向於互相混合以及擴散，因此反射率始終低於理論值。由於離子束濺鍍法低表面粗糙 度及較少缺陷的特性，因此較常被使用來鍍製極紫外光多層膜反射鏡。 因此本論文在製程溫度 60°C 下使用離子束濺鍍法鍍製 Mo/Si 多層膜， 在固定 Si 薄膜的離子束參數為 500V/30mA 下，調整濺鍍 Mo 薄膜的離子束電壓電流大小鍍製 Mo/Si 多層膜，接著使用高解析掃描穿透式電子顯微鏡觀察其界面擴散程度，並以 X 射線反射儀輔助電子顯微鏡的量測結果，最後再使用 X 射線繞射儀量測優選晶向 Mo<110>的結晶狀況。本論文亦探討加入 B4C 材料層(離子束參數 700V/40mA)與否對於多層膜的微觀結構有何影響，並以找出界面擴散程度最低的 Mo 離子束參數為最終目標。 使用 400V/50mA 的 Mo 離子束參數時獲得最低的界面擴散厚度，在 Mo-on-Si 界面與 Si-on-Mo 界面分別為 0.7nm 及 0.46nm。加入 B4C 後多層膜大部分的界面擴散厚度皆下降，其中以使用 600V/50mA 的 Mo 離子束參數下鍍製的多層膜擁有最低的界面厚度，在兩界面的擴散厚度皆為 0.43nm。 原子力顯微鏡量測的平均表面粗糙度結果皆低於 0.1nm，較低的表面 粗糙度代表極紫外光入射時會產生較少散射，獲得較高的反射率。本論文使 用 400V/50mA 及 500V/30mA 的離子源參數分別鍍製 Mo/Si 多層膜中的 Mo薄膜及 Si 薄膜，該多層膜在 Mo-on-Si 界面與 Si-on-Mo 界面的界面擴散厚度分別為 0.71nm 及 0.54nm，並以 34⁰的入射角在 13.5nm 的波長下獲得 40%的 EUV 反射率。 ;EUV reflectance of the EUV multilayer mirrors plays an important role of raising the throughput of EUVL. The component materials of EUV multilayer mirrors are Mo (molybdenum) and Si (silicon). However, the two materials tend to intermix and diffuse with each other, which makes EUV reflectance always lower than the theoretical value. Because of the lower surface roughness and fewer defects than other deposition techniques, ion beam sputter deposition is more frequently used to fabricate EUV multilayer mirrors. Thus, in this study, ion beam sputter deposition system was used to fabricate Mo/Si multilayers at 60°C. The parameters of ion beam were fixed at 500V/30mA when coating Si thin films, and those were adjusted when coating Mo thin films to fabricate different multilayers. HRTEM was used to study the degree of the interface diffusion and XRR was used to support the result of HRTEM. XRD was used to study the crystallization of the preferred orientation Mo<110>. Besides, the changes in the microstructure of multilayers with and without adding the B4C layers were also studied. Lastly, the ultimate goal of this study is to identify the parameters of the ion beam which results in the lowest degree of the interface diffusion when coating Mo thin films of the multilayer. The result indicates that the lowest thickness of the interface diffusion was achieved when using 400V/50mA as the parameters of ion beam when coating the Mo thin films of the Mo/Si multilayer, and the thickness of the interface diffusion at the Mo-on-Si interface and Si-on-Mo interface was measured as 0.7nm and 0.46nm, respectively. The addition of the B4C layers at both interfaces resulted in a decrease of the thickness of the interface diffusion for almost all the multilayers. The lowest interface thickness was achieved when using 600V/50mA as the parameters of ion beam when coating the Mo thin films of the B4C/Mo/B4C/Si multilayer, and the thickness of the interface diffusion were measured as 0.43nm at both Mo-on-Si interface and Si-on-Mo interface. The result of AFM showed that the average surface roughness of all the multilayers were below 0.1nm. The low surface roughness means that there would be less scattering while being irradiated by EUV and the multilayers would achieve higher EUV reflectance. 400V/50mA and 500V/30mA were chosen as ion beam parameters to coat Mo and Si thin films of the Mo/Si multilayer, respectively. The thickness of interface diffusion of the multilayer was respectively measured as 0.71nm and 0.54nm at Mo-on-Si interface and Si-on- Mo interface, and EUV reflectance of the multilayer was measured as 40% with 34 ﾟ incident angle at 13.5-nm wavelength.
