Review on AFM Tip-Based Mechanical Nanomachining: The Influence of the Input Machining Parameters on the Outcomes

Background: Nowadays, atomic force microscopy (AFM) tip-based nanofabrication technique has been determined as an effective material removing tool for fabricating various nanostructures due to its low cost, easy operation, nanoscale accuracy and requirement of atmospheric experimental environment. Methods: We conducted a structured search of AFM tip-based machining databases for peer-reviewed research literature using a focused classification criterion. The advantages and deficiencies of the screened papers are analyzed in detail. Results: Fifty-one papers were included in this review and they were mainly divided into five parts. Thirteen papers outlined the influence of the normal load on the machined depth and both experimental and theoretical methods to obtain the relationship between the normal load and the machined depth are discussed based on these papers. Seven papers presented the effect of the scratching velocity on the machining results and the authors found the scratching velocity have a large influence on the tip wear and the shape accuracy of the machined nanostructures. The effects of the tip geometrical shape and the scratching direction are described in five papers to demonstrate the importance of the selection of the scratching direction. Ten papers defined the influences of the sample and probe materials on the machining outcomes. They estimated the nanoscale machinability of the sample materials by using AFM-based scratching method and the tip wear after machining. Moreover, some applications of AFM-based mechanical nanomachining method were outlined in six papers. Conclusion: Following an overview of the feasibility and effectiveness of using mechanical scratching with various machining parameters, specific directions for future research in AFM tip-based mechanical scratching method is presented.