Experimental high precision profilometry of high aspect ratio samples

摘要

Topographic features on the surface of samples can be imaged by using a wide variety of profilometry methods. Scanning Probe Microscopy (SPM) comprises a group of profilometry methods that are often used for high precision, nano-scale, short range 3-D imaging. SPM can be used on a wide variety of surface types, with possible atomic resolution, relying on many physical phenomena such as inter-atomic forces, tunneling currents, capacitive and magnetic fields. The intrinsic difficulties that arise when imaging high aspect ratio surfaces-such as field emission probes, SPM probes and other "sharp and tall" micro-structures-with scanning probe profilers are mostly related to (1) image convolution, (2) sample-probe relative orientation, (3) piezo-scanner vertical range, (4) scanning-induced wear of probe and sample and (5) the location and engagement of the target feature. In this paper we discuss these practical difficulties in the imaging of high aspect ratio features and we offer some solutions.