| 摘要: | EUV微影蝕刻技術正朝著高產能、高良率的方向發展，然而EUV曝光機內Mo/Si反射鏡的介面擴散層厚度嚴重影響反射鏡光學品質，是產業朝向高產能的一個阻礙。然而離子束濺鍍法所鍍製的多層膜，能有效的減少介面擴散及降低各介面的粗糙度，加上此沉積技術能在多層膜生長中產生最少數量的缺陷，故這項技術開始受到大家的重視。
因此本論文使用離子束濺鍍系統，在60 ℃下調整離子束電壓及電流，首先鍍製Mo單層膜以及在Al2O3或SiO2上鍍製Si薄膜，並以橢偏儀進行量測，界定單層膜厚度。接著鍍製二週期Mo/Si多層膜，先使用XRR量測，IMD軟體擬合得出多層結構資訊，初步判斷調整各參數下多層膜的介面厚度變化趨勢，最後再透過TEM橫截面量測，探討離子束電壓及電流對微觀結構的影響，發現降低離子束電壓能夠減少介面擴散層厚度，離子束電流必須選擇折衷的數值，以獲得最佳介面表現。然而在TEM中Si材料的低電子吸收率，及Mo材料的高電子吸收率，造成TEM膜厚量測結果與XRR擬合數值有出入。AFM表面粗糙度結果顯示，離子束電壓的增強並未對多層膜的表面粗糙度有明顯變化，離子束電流的增強能夠平滑多層膜的表面，顯示吸附原子(ad atom)的通量多寡影響了多層膜的表面粗糙度趨勢。;UV lithography and etching technology is developing in the direction of high productivity and high yield. However, the thickness of the interface diffusion layer of the Mo/Si mirror in the EUV lithography system seriously affects the optical quality of the mirror, which is an obstacle for the industry to move towards high productivity. However, the Mo/Si multilayers deposited by ion beam sputtering can effectively reduce the interface diffusion and reduce the roughness of each interface. In addition, this deposition technology can produce a minimum number of defects in the growth of the multilayers, so this technology has begun to attract attention.
Therefore, in this paper, the ion beam sputtering system was used to adjust the ion beam voltage and current at 60 ℃℃. First, Mo monolayer was deposited and Si thin film was deposited on Al2O3 or SiO2,and measured with ellipsometer to define the thickness of the monolayer. Next, two pairs of Mo/Si multilayers was deposited, firstly measured by XRR, and fitted with IMD software to obtain the multilayers structure information, and preliminarily judged the change trend of the interface thickness of the multilayers under the adjustment of various parameters, Finally, the effects of ion beam voltage and current on the microstructure were investigated through TEM cross-sectional measurement. It was found that decreasing the ion beam voltage can reduce the thickness of the interface diffusion layer, and the ion beam current must be selected to compromise the value to obtain the best interface performance. However, in TEM, the low electron absorptivity of Si material and the high electron absorptivity of Mo material lead to the discrepancy between the measured results of TEM film thickness and the fitting values of XRR. The AFM surface roughness results showed
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that the enhancement of ion beam voltage did not significantly change the surface roughness of the multilayers, and the enhancement of ion beam current could smooth the surface of the multilayers, indicating that the flux of ad atoms affected the surface roughness trend. |
