In-situ experiment on critical thickness of brittle-ductile transition of single-crystal silicon
-
摘要: 為提高單晶硅納米切削表面質量的同時, 不影響加工效率, 以掃描電子顯微鏡高分辨在線觀測技術為手段, 在真空環境下開展了單晶硅原位納米切削實驗研究.首先, 利用聚焦離子束對單晶硅材料進行樣品制備, 并對金剛石刀具進行納米級刃口的可控修銳.然后, 利用掃描電子顯微鏡實時觀察裂紋的萌生與擴展, 分析了單晶硅納米切削脆性去除行為.最后, 分別采用刃口半徑為40、50和60 nm的金剛石刀具研究了晶體取向和刃口半徑對單晶硅脆塑轉變臨界厚度的影響.實驗結果表明: 在所研究的晶體取向范圍內, 在(111)晶面上沿[111]晶向進行切削時, 單晶硅最容易以塑性模式被去除, 脆塑轉變臨界厚度約為80 nm.此外, 刀具刃口半徑越小, 單晶硅在納米切削過程中越容易發生脆性斷裂, 當刀具刃口半徑為40 nm時, 脆塑轉變臨界厚度約為40 nm.然而刀具刃口半徑減小的同時, 已加工表面質量有所提高, 即刀具越鋒利越容易獲得表面質量高的塑性表面.Abstract: Single-crystal silicon is widely used in optoelectronics and micro-electromechanical systems because of its unique physical and chemical properties. Ductile-mode removal of single-crystal silicon can be realized by strictly controlling the cutting parameters, which significantly affect the machining efficiency. To improve the surface quality without reducing the machining efficiency, nanometric cutting experiments were performed using high-resolution scanning electron microscopy (SEM) with online observation. First, the samples were prepared, and the nanometric cutting edge of a diamond cutting tool was fabricated by focused ion beam (FIB) technology. Then, the initiation and propagation of the micro cracks were observed online by scanning electron microscopy to analyze the machining behavior of single-crystal silicon in brittle mode. Finally, using diamond cutting tools with edge radii of 40, 50, and 60 nm, respectively, the effects of crystal orientation and tool edge radius on the critical thickness of brittle-ductile transition of single-crystal silicon were studied. The experimental results show that in the presently studied crystal orientations, single-crystal silicon is most easily removed in the ductile mode along the[111] direction on the (111) plane, where the critical thickness of brittle-ductile transition is about 80 nm. In addition, the smaller the tool edge radius is, the more prone is the single-crystal silicon to brittle fracture in the nanocutting process. When the tool edge radius is 40 nm, the critical thickness of brittle-ductile transition is about 40 nm. However, the machined surface quality increases with decrease of the tool edge radius. This indicates that the sharper the cutting tool, the easier it is to obtain a high-quality surface.
-
表 1 單晶硅不同晶向脆塑轉變臨界厚度
Table 1. Critical thickness of brittle-ductile transition of single-crystal silicon in different orientations
晶面 晶向 脆塑轉變臨界厚度/nm 第1次 第2次 第3次 平均值 (110) [001] 40 45 45 43.3 [111] 70 70 65 68.3 (111) [001] 55 50 55 53.3 [111] 80 75 85 80.0 表 2 刀具刃口半徑對表面質量及脆塑轉變臨界厚度的影響
Table 2. Effect of tool edge radius on surface quality and critical thick-ness of brittle--ductile transition
刃口半徑/nm 脆塑轉變厚度/nm 表面粗糙度/nm 40 40 4. 62 50 55 6. 56 60 70 7. 81 259luxu-164 -
參考文獻
[1] Arif M, Rahman M, San W Y. A state-of-the-art review of ductile cutting of silicon wafers for semiconductor and microelectronics industries. Int J Adv Manuf Technol, 2012, 63(5-8): 481 doi: 10.1007/s00170-012-3937-2 [2] Zhou M, Wang X J, Ngoi B K A, et al. Brittle-ductile transition in the diamond cutting of glasses with the aid of ultrasonic vibration. J Mater Process Technol, 2002, 121(2-3): 243 doi: 10.1016/S0924-0136(01)01262-6 [3] Zhao H W, Yang B H, Zhao H J, et al. Test of nanomechanical properties of single crystal silicon. Opt Precis Eng, 2009, 17(7): 1602 doi: 10.3321/j.issn:1004-924X.2009.07.016趙宏偉, 楊柏豪, 趙宏健, 等. 單晶硅納米力學性能的測試. 光學精密工程, 2009, 17(7): 1602 doi: 10.3321/j.issn:1004-924X.2009.07.016 [4] Gong S, Ren X C, Chen G, et al. Effect of microstructure on the cleavage fracture stress of high-speed railway wheel steel. Chin J Eng, 2016, 38(4): 522 https://www.cnki.com.cn/Article/CJFDTOTAL-BJKD201604011.htm龔帥, 任學沖, 陳剛, 等. 微觀組織對高速車輪鋼解理斷裂應力的影響. 工程科學學報, 2016, 38(4): 522 https://www.cnki.com.cn/Article/CJFDTOTAL-BJKD201604011.htm [5] Chavoshi S Z, Goel S, Luo X C. Influence of temperature on the anisotropic cutting behaviour of single crystal silicon: a molecular dynamics simulation investigation. J Manuf Processes, 2016, 23: 201 doi: 10.1016/j.jmapro.2016.06.009 [6] Yao M Q, Tang B, Su W. Morphologic control of wet anisotropic silicon etching. Opt Precis Eng, 2016, 24(2): 350 https://www.cnki.com.cn/Article/CJFDTOTAL-GXJM201602014.htm姚明秋, 唐彬, 蘇偉. 單晶硅各向異性濕法刻蝕的形貌控制. 光學精密工程, 2016, 24(2): 350 https://www.cnki.com.cn/Article/CJFDTOTAL-GXJM201602014.htm [7] Lee S H. Analysis of ductile mode and brittle transition of AFM nanomachining of silicon. Int J Mach Tools Manuf, 2012, 61: 71 doi: 10.1016/j.ijmachtools.2012.05.011 [8] Wu H, Melkote S N. Effect of crystallographic orientation on ductile scribing of crystalline silicon: role of phase transformation and slip. Mater Sci Eng A, 2012, 549: 200 doi: 10.1016/j.msea.2012.04.034 [9] Wang M H. Research on Mechanism of Brittle-Ductile Transition and Influencing Factors of Ultra-Precision Turning Single Crystal Silicon[Dissertation]. Harbin: Harbin Institute of Technology, 2006王明海. 單晶硅超精密切削脆塑轉變機理及影響因素的研究[學位論文]. 哈爾濱: 哈爾濱工業大學, 2006 [10] Uesugi A, Hirai Y, Tsuchiya T, et al. Size effect on brittle-ductile transition temperature of silicon by means of tensile testing//2015 28th IEEE International Conference on Micro Electro Mechanical Systems. Estoril, 2015: 389 [11] Wang Z G, Zhang P, Chen J X, et al. Effect of C-C bond breakage on diamond tool wear in nanometric cutting of silicon. Acta Phys Sin, 2015, 64(19): ArtNo. 198104 https://www.cnki.com.cn/Article/CJFDTOTAL-WLXB201519044.htm王治國, 張鵬, 陳家軒, 等. 單晶硅納米切削中C-C鍵斷裂對金剛石刀具磨損的影響. 物理學報, 2015, 64(19): ArtNo. 198104 https://www.cnki.com.cn/Article/CJFDTOTAL-WLXB201519044.htm [12] Fang F Z, Xu F F, Lai M. Size effect in material removal by cutting at nano scale. Int J Adv Manuf Technol, 2015, 80(1-4): 591 doi: 10.1007/s00170-015-7032-3 [13] Han X S, Lin B, Yu S Y, et al. Investigation of tool geometry in nanometric cutting by molecular dynamics simulation. J Mater Process Technol, 2002, 129(1-3): 105 doi: 10.1016/S0924-0136(02)00585-X [14] Liu K, Li X P, Rahman M, et al. A study of the effect of tool cutting edge radius on ductile cutting of silicon wafers. Int J Adv Manuf Technol, 2007, 32(7): 631 doi: 10.1007/s00170-005-0364-7 [15] Mir A, Luo X C, Sun J N. The investigation of influence of tool wear on ductile to brittle transition in single point diamond turning of silicon. Wear, 2016, 364-365: 233 doi: 10.1016/j.wear.2016.08.003 [16] Zhu B, Zhao D, Zhao H W, et al. A study on the surface quality and brittle-ductile transition during the elliptical vibration-assisted nanocutting process on monocrystalline silicon via molecular dynamic simulations. RSC Adv, 2017, 7: 4179 doi: 10.1039/C6RA25426H [17] Fang F Z, Liu B, Xu Z W. Nanometric cutting in a scanning electron microscope. Precis Eng, 2015, 41: 145 doi: 10.1016/j.precisioneng.2015.01.009 [18] Zhang Z Y, Wu Y Q, Guo D M, et al. Phase transformation of single crystal silicon induced by grinding with ultrafine diamond grits. Scripta Mater, 2011, 64(2): 177 doi: 10.1016/j.scriptamat.2010.09.038 -