Low-cost batch fabrication method of high aspect ratio AFM tips

原子力显微镜(AFM)是扫描探针显微镜(SPM)家族中最常用的表征工具。与扫描电子显微镜(SEM)相比，AFM的成本更低，如果样品是平的，则在z方向和x-y方向的精度要高得多(高一个数量级)，并且可以与绝缘样品甚至在液体环境中同样好地工作。然而，在表面结构表征方面，扫描电子显微镜仍然比原子力显微镜更受欢迎，这主要是因为在绘制非平坦表面(例如，深而窄的孔/沟槽)时，AFM图像的内在限制，其中尖端不能完全跟随样品表面。克服这个问题的自然解决方案是使用薄的和高纵横比的尖端，这样可以更精确地跟踪样品表面。

Atomic force microscope (AFM) is the most popular characterization tool among the scanning probe microscope (SPM) family. Compared to scanning electron microscope (SEM), AFM has lower cost, much more accurate (by one order) in the z-direction and x-y direction if the sample is flat, and can work equally well with insulating sample or even inside a liquid environment. Nevertheless, SEM is still far more popular than AFM for topographical structure characterization, mostly because of the intrinsic limit in the AFM image when mapping a none-flat surface (e.g a deep and narrow hole/trench) where the tip cannot fully follow the sample surface. The natural solution to overcome this issue is by using thin and high aspect ratio tips that can follow the sample surface more precisely.