基于原子力顯微鏡的線寬粗糙度測量

李洪波 趙學增
哈爾濱工業大學機電工程學院,哈爾濱150001
摘　要:給出采用原子力顯微鏡（Atomic force microscope,AFM）測量線寬粗糙度（Line width roughness,LWR）的分析步驟。分析線寬和LWR及其偏差隨刻線橫截面位置的高度變化的關系,線寬及其偏差和LWR及其偏差隨刻線橫截面位置的高度值增加而減小。分別采用四種邊緣提取算子提取了碳納米管針尖AFM測量的刻線頂部線寬邊緣,計算了刻線頂部線寬和LWR,頂部線寬和LWR測量結果對邊緣提取算子不敏感。結合被測單晶硅臺階的頂表面和底表面加工方法,提出采用各掃描線輪廓高度相等的方法校正AFM壓電驅動器的z向非線性。比較了采用普通氮化硅探針針尖、超尖針尖以及碳納米管針尖AFM測量名義線寬為1000 nm刻線LWR的結果,顯示采用三種針尖的LWR測量結果存在差異,但考慮到AFM分辨率,可認為測量結果基本相同。因此,為更精確描述刻線邊緣,必須提高AFM分辨率。[著者文摘]
Measurement of Line Width Roughness by Using Atomic Force MicroscopeLI Hongbo, ZHAO Xuezeng School of Mechanical and Electrical Engineering, Harbin Institute of Technology, Harbin 150001Abstract:The analytical procedures are illustrated of the measurement of line width roughness （LWR） by using atomic force microscope （AFM）. The relations are presented of line-width, line-width error vs. the height. With the increase of the height, the line width and its error become smaller. The trend of LWR and its error vs. height is the same as that of line-width vs. height. The four operators, i.e., Roberts, Sobel, Canny and Prewitt are respectively used to detect the edges on the top surface measured by using AFM with the carbon nanotube tip. Then the line width and LWR on the top-surface are calculated, which shows that different operators have almost no effect on the line width and LWR. A method to verify the nonlinear in z direction of the piezoelectric actuator of AFM is brought forward in terms of the processing technology on the top and bottom surface of the measured single crystal silicon step. In the method, the height of the scanning profile is equal to one another. LWR is compared with one another which are measured respectively by using AFM with the ordinary tip, the ultra-sharp tip and the carbon nanotube tip. There is no remarkable difference about the step in 1 000 nm nominal line width. Thus the resolution of AFM must be improved in order to get more accurate topography of sidewall.[著者文摘]

Key words:Nano-measurement Line-width roughness （LWR） Atomic force microscope （AFM） Nonlinearity of the piezoelectric actuator Tip