掃描式電子顯微鏡內部的奈米加工與測試技術研究

Nano-machining and Mechanical Testing of Nano-materials inside a Scanning Electron Microscope

李伸家(Shen-Chia Li)

指導教授 ： 章明

中原大學/工學院/機械工程學系/碩士(2007年)

https://doi.org/10.6840/cycu200700682

摘要

本研究以一套可在掃描電子顯微鏡內部執行三維奈米機械操作之系統，進行奈米加工及測試研究，此系統整合壓電馬達、精密平台等設備，為一個四自由度的精密系統，包含X、Y、Z三軸及一個旋轉軸，具有在立體空間中進行奈米加工及測試的功能，並且可以執行奈米材料或結構的現地機械性質測試。理論模式係根據材料特性運用分子動力學模擬加工過程，採用Morse 勢能函數，結合牛頓第二定律，並預測分子的速度及位置，控制系統溫度，進行加工特性分析，並對於切削深度不同時，所移除的體積，以求得奈米加工的行為及特性。
在加工部分，以原子力顯微鏡使用的矽碁探針，在濺鍍金之玻璃上進行加工，並建立回授控制來提升加工的精確性，在加工方向X、Y軸利用軟體補償進給量與輸入參數之間的誤差，而在深度方面，則利用影像回授來控制加工深度。加工結果以原子力顯微鏡進行量測比對，並驗證分子動理學模擬結果，目前已具備製作奈米線並刻劃出清晰可辨的奈米文字，並用以使用過較頓的刀具配合影像回授控制將加工過的切屑移除以及製作微流道。
在材料測試部分，使用微波水熱法所合成的二氧化鈦奈米結構進行現地機械性質實測，將直徑100~150nm左右的二氧化鈦奈米線使用EBID的方式黏結於成對的原子力顯微鏡的探針上，利用電子顯微鏡所擷取的影像分析探針懸臂樑的變形量和二氧化鈦奈米線挫曲變化，結合以穿邃式電子顯微鏡量得的截面積，配合傳統挫曲公式即可反算出二氧化鈦奈米線的材料常數，目前所測得的二氧化鈦奈米線彈性係數約為16.312±1.052 GPa。

關鍵字

EBID ； 奈米加工 ； 二氧化鈦奈米線 ； 奈米機械操作系統 ； 掃描式電子顯微鏡 ； 挫曲

並列摘要

The present investigation describes about the applications of a four degrees of nano-manipulator system for three-dimensional nano-machining and nanomechanical characterization of nanoscale objects inside a scanning electron microscope (SEM). The nanomanipulation system consists of precisely machined platform, picomotors and monolithic-silicon-based tips which are generally used in atomic-force microscopes (AFM).
The manipulator system is used for two different applications,
(i) Nano machining of gold coated silicon substrate
(ii) Nanomechanical characterization of TiO2 nanowires (NWs)
In nano-machining, the AFM tip is used to pattern nano-materials such as gold (Au) coating on silicon. Image feedback control method is used for precise machining and the processed results are determined with AFM. Molecular dynamics simulation method is used to analyze the experimental results by considering different parameters such as cutting speed and volume remove for different cutting depth etc. Hence nano machining with the manipulator can produce nano-lines, readable nano-scale words and micro channels. Moreover, it can also chuck out the removed material from the sample surface.
The manipulator system is used to determine the elasticity co-efficient NWs by employing compression experiment. NWs are synthesized by microwave hydrothermal method. The electron beam induced deposition (EBID) method is used to clamp NWs to the AFM tips attached to the nanomanipulator platform inside the SEM vacuum chamber. The buckling instability of the NWs is studied by applying continuously increasing load on it and analyzed from a series of SEM image. The Young’s modulus of the NWs is determined using Euler buckling model. To measure the cross sectional area of the NWs, aluminum is coated on NWs to improve resolution of SEM images. The Young’s modulus of the NWs has been measured to be 16.31±1.05GPa.

並列關鍵字

nano-machining ； buckling ； EBID ； nano-manipulator system ； TiO2 nanowire ； Scanning electronic microscope

參考文獻

[1] D. M. Eigler and E. k. Schweizer, “Positioning single atoms with a scanning tunneling microscope,” Nature, Vol.344, p.524, 1990.

[2] S. Iijima, “Helical microtubules of graphitic carbon,” Nature, Vol.354, p.56, 1991.

[3] H. J. Qi, K. B. Teo, K. S. Lau, M. C. Boyce, W. I. Milne, J. Robertson, and K. K. Gleason, “Dtermination of mechanical properties of carbon nanotubes and vertically aligned carbon nanotube forests using nanoindentation,” Journal of Mechanics and Physics of Solids, Vol.51, p.2213, 2003.

[4] M. F. Yu, M. J. Dyer, G. D. Skidmore, H. W. Rohrs, X. K. Lu, K. D. Ausman, J. R. V. Her, and R. S. Rouff, “Three-dimensional manipulation of carbon nanotubes under a scanning electron microscope,” Nanotechnology, Vol.10, p.244, 1999.

[5] M. F. Yu, B. S. Files, S. Arepalli, and R. S. Ruoff, “Tensile loading of ropes of single-walled carbon nanotubes and their mechanical properties,” Physical Review Letters, Vol.84, p.5552, 2000.