Full Length ArticleExperimental investigation of the tip based micro/nano machining
Introduction
Nowadays, the fabrication of nanochannel and nanostructure is a hot issue in micro/nano field. There are many different methods, such as photolithography [1], LIGA [2], FIB (Focused Ion Beam) technology [3], nanoimprint [4] and tip based nanomanufacturing (TBN) [5]. Among all of these methods, every technique has its own advantages and special applications, but the tip based micro/nano machining is attracting more and more attention for the low-cost, simple operation and high accuracy. The scanning tunneling microscopy (STM), atomic force microscope (AFM) and nanoindenter are three common devices for the TBN technology, especially the application of AFM makes this technology greatly developed, and it has successfully combined the chemical and thermal effects to the traditional mechanical removal [6].
In the AFM tip based mechanical nanomanufacturing, the effects of machining parameters including applied normal load, scratching direction, scratching cycles, scratching speed and scratching feed on the machined depth and surface roughness have been investigated by many scholars in the last decades [7], [8], [9], [10], [11], [12], [13]. Recently, some researchers focus on the theoretical modeling of scratching depth. Wang studied the relationship between the initial and final nanochannel depth through both theoretically and experimentally [14], [15]. Geng modeled the scratching depth theoretically in both single and multiple scratching, and micro/nano structures were manufactured based on the proposed model [16]. Lin estimated the cutting depth based on regression equations of nanoscale contact pressure factor and specific down force energy, respectively [17].
The probe cantilever of the AFM is essentially a single flexible beam, as a result, the stiffness of the AFM cantilever in the longitudinal direction is different from that in the transverse direction, which affects the experimental results when scratching in different directions. Unfortunately, the tip-sample interface is also affected by the scratching direction due to the tip geometrical asymmetry. These factors make the investigation of scratching direction complex. Moreover, the AFM cantilever is usually very soft in the vertical direction, which makes it sensitive to the environmental changes. Finally, the low positioning precision of the AFM motion platform reduces the machining accuracy in xy plane. In order to overcome these shortcomings of the AFM, many different mechanical designs have been proposed for the micro/nano machining. Lee adopted a strain gauge measured load beam to substitute the AFM cantilever [18]. Park designed a displacement-force device to realize the micro/nano machining [19]. Jeong presented an air lubricated hydrostatic sliding mechanism based portable nano probe system [20]. Gozen constructed a nano milling system to fabricate the micro channel [21]. All these designs can realize the micro/nano structure scratching, but they also have obvious drawbacks, such as the overlarge normal load in Lee’s mechanism, the residual friction of the probe shaft in Jeong’s design, and the limitation of machining width in Gozen’s system. As to the position precision in xy plane, the piezo-actuated flexure-mechanism is a good choice to solve this problem, which has been studied by many scholars [22], [23], [24], [25].
In this paper, a self-developed three dimensional micro/nano machining system is used for the experimental investigation, which mainly includes the probe system and precise positioning stage. The cross-shaped probe suspension mechanism in the probe system effectively avoids the singal axis and low stiffness of the AFM cantilever. Before the scratching experiments, an examination method is presented to examine the horizontal place of the sample. Subsequently, the scratching parameters including scratching direction, normal load, scratching cycles, scratching speed and scratching feed are systematically investigated and analyzed. Further, the copper sample is scratched and the material removal results are compared with those of silicon samples. Finally, some more micro structures are fabricated on the silicon base with the selected scratching parameters.
Section snippets
The micro/nano machining system
All of experiments are performed in a self-developed three dimensional micro/nano machining system, which is shown in Fig. 1. The overall frame applies the gantry structure. Three manual coarse mobile platforms (WN115TM50 M, winner optical instruments, China) arranged orthogonally are used to realize the broad adjustment with the full stroke of 50 mm and minimal regulating amount of 2 μm. The probe system and the 3-DOF micro/nano positioning stage are the two core parts of the machining system,
The experimental investigation
In the experimental investigation, the silicon is firstly selected as the sample for the wide application in semiconductor industry. After micro/nano machining, the sample is cleaned using ultrasonic wash with acetone solution for ten minutes to remove the generated chips, and then the machined micro/nano grooves or structures are measured using AFM (CSPM5500, Benyuan, China).
Three dimensional micro/nano machining
Based on the above experimental results, some additional three dimensional micro/nano structures are fabricated on silicon substrate by controlling the normal force. The following machining parameters are adopted: scratching direction d3/d4, scratching speed 5 μm/s and feed 60 nm.
Fig. 16 shows the normal force used for the fabrication of a stair micro/nano structure and the corresponding experimental result. The average scratching depth in right stair is about 10 nm smaller than the left one, the
Conclusion
In the micro/nano machining, the machining parameters include scratching direction, normal load, scratching cycles, scratching speed and feed amount. According to the experimental results, the scratching depth in the d2, d3/d4 and d1 directions is successively reduced, but it is affected more obvious by the normal load. Multi scratching can also increase the scratching depth, and the groove become smoother as the number of scratching cycle number increases. The scratching depth difference is
Acknowledgements
This research is supported by National Natural Science Foundation of China (Nos. 51675371, 51675367, 51675376, 51405333, 51420105007) and EU H2020 FabSurfWAR (No. 644971).
References (30)
- et al.
Review Developments in micro/nanoscale fabrication by focused ion beams
Vacuum
(2012) - et al.
Tip-based nanomanufacturing by electrical, chemical, mechanical and thermal processes
Cirp Ann. − Manuf. Technol.
(2010) - et al.
Recent advances in AFM tip-based nanomechanical machining
Int. J. Mach. Tools Manuf.
(2015) - et al.
effects of AFM-based nanomachining process on aluminum surface
J. Phys. Chem. Solids
(2003) - et al.
Investigation on AFM-based micro/nano-CNC machining system
Int. J. Mach. Tools Manuf.
(2007) - et al.
Fabrication of millimeter scale nanochannels using the AFM tip-based nanomachining method
Appl. Surf. Sci.
(2013) - et al.
Influence of double-tip scratch and single-tip scratch on nano-scratching process via molecular dynamics simulation
Appl. Surf. Sci.
(2013) - et al.
Atomic force microscopy-based repeated machining theory for nanochannels on silicon oxide surfaces
Appl. Surf. Sci.
(2011) - et al.
Material removal model for AFM-based nanochannel fabrication
Wear
(2012) - et al.
Modelling and experimental study of machined depth in AFM-based milling of nanochannels
Int. J. Mach. Tools Manuf.
(2013)
Application of single asperity abrasion process for surface micro-machining
Wear
Design and evaluation of a mechanical nanomanufacturing system for nanomilling
Precis. Eng.
Design. development and analysis of a haptic enabled modular flexure mechanism
Mechatronics
Design and analysis of a novel flexure-based 3-DOF mechanism
Mech. Mach. Theory
Design and control methodology of a 3-DOF flexure-based mechanism for micro/nano positioning
Rob. Comput. Integr. Manuf.
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