AFM扫描过程的模拟及针尖形状反求

纳米栅格和台阶等结构的线宽准确测量,是国内外计量领域的研究热点与难点。采用原子力显微镜(AFM)能获得上述结构的三维形貌信息,但其扫描图像却是探针针尖的形貌和被测样品表面的形貌共同作用的结果,这种作用往往导致线宽边缘测量失真。为了更加精确地获得样品的表面形貌特征,首先需要重建探针针尖形貌,进而从得到的扫描图像中尽可能地消除由探针形貌带来的失真影响。基于数学形态学的盲重建理论,利用Matlab对不同形状参数的探针针尖扫描台阶样品表面进行了仿真,评价了探针形状对扫描结果的影响,初步实现了基于真实粗糙测量表面的探针针尖形状重建。

Simiulation of AFM Scanning Process and Tip Shape Estimation

To accurate measure the line widths of nano-grid and step structure is the hottest issues in metrology domain. AFM can be used to obtain the three-dimensional topographic information of the above structure, but the scanned image is the result of the interaction between the shape of the tip and the surface morphology of the sample. This interaction often leads to line width edge measurement distortion. To more accurately obtain the surface topography of the sample, firstly, the shape of the tip needs to be reconstructed, and then the distortion effect brought by the tip topography is eliminated as much as possible from the scanned image. Based on the blind reconstruction theory of mathematical morphology, Matlab was used to simulate the stepped sample surface scanned by different shape parameters of tips, the influences of the probe tip shape on the scanning results were evaluated, and got the initial realization of probe tip shape reconstruction based on measuring rough surface.