双探针原子力显微镜针尖对准方法研究

Study on Tip Alignment Method of Dual-probe Atomic Force Microscopy

双探针对顶测量可以有效地消除传统原子力显微镜（AFM）的探针形状对关键尺寸（CD）测量的影响。测量前需要将两个探针针尖（A和B）接触到一起作为测量零点，为实现双探针纳米级对准，提出一种渐进式平面扫描方法。首先，通过视觉图像引导两个探针对准到1μm以内。然后，两个探针继续接近，同时探针A在YOZ平面内对探针B扫描成像，并逐步缩小扫描范围和扫描步进，得到其针尖的纳米级坐标（YB，ZB）。最后，将探针A在Y和Z方向分别移动至YB和ZB，在X方向继续接近探针B直至两探针接触。实验证明，该方法可有效地实现双探针对准，且对准精度为10nm。

Dual probes alignment measurement can virtually eliminate the effect of tip shape of traditional atomic force microscopy （AFM） on critical measurement （CD）. Two tips （probe A and probe B ） need contact to each other before measurement to establish a zero reference point. A method of progressive two-dimensional scanning is used to realized dual- probe nanoscale alignment. Firstly, it will align two probes to within 1 μm through vision guidance. Secondly, the two probes continue to close, probe B is scanned by probe A in plane XOZ while reducing the scanning range and scanning step gradually to get the nanometer coordinate of probe B （ YB ,ZR）- Lastly, the probe A will be move to YB and ZB in X and Z directions respectively, untill the probe A moves to touch the probe B in X direction. Results indicated that this method can effectively align dual probes, and the alignment accuracy is 10 nm.