基于AFM单晶硅台阶线边缘粗糙度、顶表面和底表面粗糙度的测量

Line Edge Roughness and Top-bottom-surface Roughness Measurement of Single-crystal-silicon Step Using AFM

采用原子力显微镜以TOP-DOWN方式测量单晶硅刻线单侧形貌。提出以单次扫描线上5个最低测量值的平均值为高度参考点且各条扫描线参考高度在统计意义下相等,校正(原子力显微镜)AFM压电驱动器高度方向非线性。通过NIST高度算法和直方图方法相结合确定样本边缘表面、顶表面和底部表面范围。顶表面和底表面各扫描线的功率谱密度(PSD)、均方根值(RMS)基本一致。对于边缘粗糙度而言,RMS随测量高度增加而减小;PSD随高度增加主导频率范围略有降低但变化不明显。

Single side topography on the single-crystal-silicon step is measured by AFM （atomic force microscope） in top-down mode. The way to verify the nonlinearity of the piezoelectric actuator in AFM is proposed： to regard the mean height of the 5 lowest points in each scan-line as the height reference point, and the reference points＇ height of all scan-lines are equivalent to each other. Based on this, the nonlinearity of the piezoelectric actuator of AFM is verified. The edge, top and bottom surface range of the sample are determined respectively by using the NIST （National Institute of Standards and Technology） height-algorithm integrated with histogram. The root mean square （RMS） and the power spectral density （PSD） of each scan-line roughness on the top-bottom-surfaces are the same. As for the line edge roughness, RMS decreases when the height increases, while, the dominant frequency range of PSD slightly reduces when the height increases, but this change is inconspicuous.