本研究發展一種新型的奈米壓印製程技術，以結合金屬輔助化學濕蝕刻(Metal Assistant Chemical Etching, MACE)的製程，應用於製作矽基板上的奈米結構。金屬輔助化學蝕刻製程一般是以傳統黃光微影技術與金屬舉離(Lift off)製程，於矽基板上定義一具微/奈米特徵的金屬催化劑圖形然後進行輔助化學蝕刻；本研究則是使用奈米壓印技術搭配舉離製程來定義此一金屬圖形。由於奈米壓印需要以乾蝕刻的氧電漿去除壓印阻劑的殘留層，可能會造成矽基板表面殘留有機物，影響到後續的金屬輔助化學蝕刻；因此，本論文提出一種雙阻劑的壓印製程，在壓印阻劑與基板之間增加一層中介層阻劑，可以在乾蝕刻後，再以濕蝕刻的方式去除矽基板上殘留的中介層阻劑，維持矽基板表面的潔淨度，進而提升後續金屬輔助化學蝕刻的蝕刻品質與蝕刻速率。
實驗製程上，以週期300 nm、直徑160 nm的六角最密洞狀與柱狀結構進行 4”~ 6” 吋矽晶圓面積的金屬層圖案定義，以傳統奈米壓印製程與新型雙阻劑奈米壓製程兩種壓印方式，以及三種去除殘留層的方法，探討乾式蝕刻與濕蝕刻去除殘留層對金屬輔助化學蝕刻的影響；最後，將所發展與建立的奈米製程技術應用於矽母模仁的複製，得到相當成功的實驗結果。

關鍵字：金屬輔助化學蝕刻、奈米壓印微影技術、舉離製程、中介層阻劑、壓印複合模具。

This thesis develops a new type of hot embossing nano-imprinting technology which can work along with Metal Assistant Chemical Etching (MACE) to fabricate nanostructures on silicon wafers. Metal-assisted chemical etching usually uses photolithography and metal lift-off processes to define micro/nano-scaled metallic patterns as the catalysis layer in MACE. In this study, nano-imprint lithography will replace photolithography to define the metallic catalysis patterns. However, dry etching using oxygen plasma is needed for removing residual resist after imprinting in conventional nano-imprinting process, but could leave organic residuals on the silicon wafer surface and hence affect the subsequent metal-assisted chemical etching. Therefore, a new type of nano-imprinting process is developed by inserting a new interfacial resist layer in between the imprinting resist layer and the substrate. After dry etching, the remaining interfacial resist can be completely removed by wet etching. This can keep the silicon substrate surface being clean and guarantee the etching quality and etching rate of metal-assisted chemical etching.
In the experiments, metallic patterns with arrayed and hexagonally close-packed hole- and pillar-structures with a period of 300 nm and a diameter of 160 nm are patterned on 4” to 6” silicon wafers. Both conventional and the proposed new nano-imprinting processes along with three different methods for removing residual layers are experimentally investigated to explore the influence of dry etching and wet etching of residual layers on the metal-assisted chemical etching. The developed new nano-fabrication processes and technologies are applied to the replication of silicon master molds, and successful results are observed.

Keywords：Metal-Assisted Chemical Etching, Nanoimprint lithography, Lift-off process, Interfacial resist, Composite imprinting mold.

[1] P. R. Fabian and S. Y. Chou, “Lithography and other patterning techniques
for future electronics,” Proceedings of the IEEE., vol. 96, no. 2, pp. 248-270,
2008.
[2] S. Y. Chou, P. R. Krausse and P. J. Renstrom, “Imprint of sub‐25 nm vias
and trenches in polymers,” Appl. Phys. Lett., vol. 6, no. 21, pp. 3114-3116,
1995.
[3] S. Y. Chou, “Nanoimprint lithography,” J. Vac. Sci. Technol. B, vol. 14, no. 6,
pp. 4129-4133, 1996.
[4] M. Colburn et al., “Step and flash imprint lithography: a new approach to
high-resolution patterning,” International Society for Optics and
Photonics., vol. 3676, pp. 379-389, 1999.
[5] Y. Xia et al., “Non-photolithographic methods for fabrication of
elastomeric stamps for use in microcontact printing,” Langmuir, vol. 12,
no. 16, pp. 4033-4038, 1996.
[6] Y. C. Lee and C. Y. Chiu, “Micro-/nano-lithography based on the contact
transfer of thin film and mask embedded etching,” J. Micromech.
Microeng., vol. 18, no. 7, p. 075013, 2008.
[7] X. Li and P. W. Bohn, “Metal-assisted chemical etching in HF/H_2 O_2
produces porous silicon,” Appl. Phys. Lett., vol. 77, no.16, pp. 2572-2574,
2000.
[8] H. Fang et al., “Fabrication of slantingly-aligned silicon nanowire arrays for
solar cell applications,” Nanotechnology, vol. 19, no. 25, p. 255703, 2008.
[9] C. Y. Chen et al., “Morphological control of single‐crystalline silicon
nanowire arrays near room temperature,” Adv. Mater., vol. 20, no. 20, pp.
3811-3815, 2008.
[10] C. Chartier, B. Stephane, and C. Levy-Clement, “Metal-assisted chemical
etching of silicon in HF–H_2 O_2,” Electrochim. Acta., vol. 53, no. 17, pp.
5509-5516, 2008.
[11] M. L. Zhang et al., “Preparation of large-area uniform silicon nanowires
arrays through metal-assisted chemical etching,” J. Phys. Chem. C, vol.
112, no. 12, pp. 4444-4450, 2008.
[12] C. L. Lee et al., “Pore formation in silicon by wet etching using
micrometre-sized metal particles as catalysts,” J. Mater. Chem. A, vol. 18,
no. 9, pp. 1015-1020, 2008.
[13] K. Tsujino and M. Matsumura, “Morphology of nanoholes formed in
silicon by wet etching in solutions containing HF and H_2 O_2 at different
concentrations using silver nanoparticles as catalysts,” Electrochimica
Acta., vol. 53, no. 1, pp. 28-34, 2007.
[14] S. Cruz, H. D. Arne, and M. Jorg, “Fabrication and optimization of porous
silicon substrates for diffusion membrane applications,” J. Electrochem.
Soc., vol. 152, no. 6, p. 418, 2005.
[15] H. Fang et al., “Silver catalysis in the fabrication of silicon nanowire
arrays,” Nanotechnology, vol. 17, no. 15, p. 3768, 2006.
[16] Z. Huang et al., “Ordered arrays of vertically aligned [110] silicon
nanowires by suppressing the crystallographically preferred<100>
etching directions,” Nano Lett., vol. 9, no. 7, pp. 2519-2525, 2009.
[17] W. K. Choi et al., “Synthesis of silicon nanowires and nanofin arrays using
interference lithography and catalytic etching,” Nano Lett., vol. 8, no. 11,
pp. 3799-3802, 2008.
[18] Z. Huang et al., “Extended arrays of vertically aligned sub-10 nm
diameter [100] Si nanowires by metal-assisted chemical etching,” Nano
Lett., vol. 8, no .9, pp. 3046-3051, 2008.
[19] S. L. Chung, C. H. Lee and H. C. Lee, “A study of the synthesis,
characterization, and kinetics of vertical silicon nanowire arrays on (001) Si
substrates,” J. Electrochem. Soc., vol. 155, no. 11, p. 711, 2008.
[20] Z. Huang, H. Fang and J. Zhu, “Fabrication of silicon nanowire arrays with
controlled diameter, length, and density,” Adv. Mater., vol. 19, no. 5, pp.
744-748, 2007.
[21] K. Q. Peng et al., “Fabrication of single‐crystalline silicon nanowires by
scratching a silicon surface with catalytic metal particles,” Adv. Funct.
Mater., vol. 16, no. 3, pp.387-394, 2006.
[22] Z. Huang et al., “Metal‐assisted chemical etching of silicon,” Adv. Mater.,
vol. 23, no. 2, pp. 285-308, 2011.
[23] 杜珮綺, “奈米壓印暨黑光阻嵌入式軟性光罩之微奈米製程與應用,” 國立成功
大學機械工程學系碩士論文, 2019.
[24] 朱致緯, “奈米壓印微影製程應用於高頻表面聲波元件之製作與實驗量測,” 國
立成功大學機械工程學系碩士論文, 2019.
[25] K. Mogi et al., “Nanometer-level high-accuracy molding using a photo-
curable silicone elastomer by suppressing thermal shrinkage,” RSC Adv.,
vol. 5, no. 14, pp. 10172-10177, 2015.
[26] N. Chidambaram et al., “High fidelity 3D thermal nanoimprint with UV
curable polydimethyl siloxane stamps,” J. Vac. Sci. Technol. B, vol. 34, no
.6, p. 401, 2016.
[27] 陳宥翔, “可控制壓力分佈的奈米壓印技術與軟性光罩的曲面黃光微 影製程,”
國立成功大學機械工程學系碩士論文, 2020.
[28] T. T. Truong et al., “Soft lithography using acryloxy perfluoropolyether
composite stamps,” Langmuir, vol. 23, no. 5, pp. 2898-2905, 2007.
[29] D. R. M. van and M. W. Bockrath, “Solvent-resistant elastomeric
microfluidic devices and applications,” Ph.D. thesis, California Institute of
Technology, Pasadena, CA, 2006.
[30] 半導體晶圓廠的清潔劑，三聯科技股份有限公司 /張和裕
[31] V. Lehmann, Electrochemistry of Silicon Instrumentation, Science,
Materials and Applications. Weinheim: Wiley-VCH, 2002.
[32] X. Geng et al., “Metal-assisted chemical etching using Tollen’s reagent
to deposit silver nanoparticle catalysts for fabrication of quasi-ordered
silicon micro/nanostructures,” J. Electron. Mater., vol. 40, no. 12, pp.
2480-2485, 2011.
[33] K. Q. Peng et al., “Fabrication of single‐crystalline silicon nanowires by
scratching a silicon surface with catalytic metal particles,” Adv. Funct.
Mater., vol. 16, no. 3, pp. 387-394, 2006.
[34] 巫宗華, “利用自組裝高分子共聚物模板與金屬輔助化學蝕刻製備奈微複合結構
之研究,” 國立清華大學工程與系統科學系碩士論文, 2015.
[35]K. Peng et al., “Motility of metal nanoparticles in silicon and induced
anisotropic silicon etching,” Adv. Funct. Mater., vol. 18, no. 19, pp. 3026-
3035, 2008.
[36] M. L. Zhang et al., “Preparation of large-area uniform silicon nanowires
arrays through metal-assisted chemical etching,” J. Phys. Chem. C, vol
112, no. 12, pp. 4444-4450, 2008.
[37] X. H. Xia et al., “Galvanic cell formation in silicon/metal contacts the
effect on silicon surface morphology,” Chem. Mater., vol. 12, no. 6, pp.
1671-1678, 2000.
[38] K. Q. Peng et al., “Fabrication of single‐crystalline silicon nanowires by
scratching a silicon surface with catalytic metal particles,” Adv. Funct.
Mater., vol. 16, no. 3, pp. 387-394, 2006.
[39] L. Kong et al., “Minimizing isolate catalyst motion in metal-assisted
chemical etching for deep trenching of silicon nanohole array,” ACS Appl.
Mater. Interfaces, vol. 9, no. 24, pp. 20981-20990, 2017.
[40] D. Brodoceang et al., “Dense arrays of uniform submicron pores in silicon
and their applications,” ACS Appl. Mater. Interfaces, vol. 7, no. 2, pp.
1160-1169, 2015.
[41] C. Chang, and A. Sakdinawat, “Ultra-high aspect ratio high-resolution
nanofabrication for hard X-ray diffractive optics,” Nat. Commun., vol. 5,
no. 1, pp. 1-7, 2014.
[42] K. Q. Peng et al., “High-performance silicon nanohole solar cells,” J. Am.
Chem. Soc., vol. 132, no. 20, pp. 6872-6873, 2010.
[43] F. Guder et al., “Tracing the migration history of metal catalysts in metal-
assisted chemically etched silicon,” ACS Nano, vol. 7, no. 2, pp. 1583-
1590, 2013.
[44] Micro Resist Technology,“ mr-l 7000R Series：Thermoplastic Polymer for
Nanoimprint Lithography with Optimized Release Properties,” mr-l
7000R series Data Sheet, Rev May 2020.
[45] Kayaku Advanced Materials, “LOR and PMGI Resists for Bi-layer Lift-off
Processing,” LOR/PMGI Technical Data Sheet, Rev. B, November 2019.
[46] K. Q. Peng et al., “Fabrication and photovoltaic property of ordered
macroporous silicon,” Appl. Phys. Lett., vol. 95, no. 14, p. 143119, 2009.
[47] C. Q. Lai, and W. K. Choi, “Synthesis of free-standing curved Si nanowires
through mechanical failure of a catalyst during metal assisted chemical
etching,” Phys. Chem. Chem. Phys., vol. 16, no. 26, pp. 13402-13408,
2014.
[48] C. Q. Lai et al., “Mechanics of catalyst motion during metal assisted
chemical etching of silicon,” J. Phys. Chem. C, vol. 117, no. 40, pp. 20802-
20809, 2013.
[49] K. Peng et al., “Motility of metal nanoparticles in silicon and induced
anisotropic silicon etching,” Adv. Funct. Mater., vol. 18, no. 19, pp. 3026-
3035.
[50] O. Hildreth, J. LIN, W. Wong, and C. Ping, “Effect of catalyst shape and
etchant composition on etching direction in metal-assisted chemical
etching of silicon to fabricate 3D nanostructures,” ACS Nano, vol. 3, no.
12, pp. 4033-4042, 2009.
[51] K. Rykaczewski et al., “Guided three-dimensional catalyst folding during
metal-assisted chemical etching of silicon,” Nano Lett., vol. 11, no. 6, pp.
2369-2374, 2011.
[52] R. C. Tiberio et al., “Vertical directionality-controlled metal-assisted chemical
etching for ultrahigh aspect ratio nanoscale structures,” J. Vac. Sci. Technol. B,
vol. 32, no. 6, p. 06FI01, 2014.