本研究所提出的鑲入式奈米壓印(Insertion nanoimprint)技術，乃是結合逆式奈米壓印(Reversal nanoimprint)及奈米壓印(Nanoimprint)的製程特色，達到可同時轉印金屬結構與定義基材圖案的目的，也就是將矽晶圓表面上的奈米級金屬線條(本研究使用鋁金屬/銅金屬)，以適當的溫度與壓力，壓入介電質材料(本研究使用PMMA)之中。本壓印技術所製作的鑲入式奈米結構(Insertion structure)之特點在於能將金屬光柵穩定鑲嵌於介電質材料之中，並提供平整的加工完成表面，以避免搬運或組裝過程中，因應力或灰塵所造成之破壞或污染、具有穩固的機械結構及簡化後續封裝製程的優點。同時，為了簡化鑲入式奈米壓印技術，本研究另行開發一套包括奈米壓印、鋁金屬/銅金屬沉積與化學機械研磨(Chemical Mechanical Polishing, CMP)的高效率製程，使其能在製作鑲入式奈米結構之同時，兼顧大量生產的需求。
具有鋁金屬線條(Al wire gratings)的鑲入式奈米結構，當其鋁光柵週期小於入射光波長之一半時，將具有偏光的效果，因此可應用在偏極板(Polarizer)等光學元件；再者，為了達到高偏光效果的要求，必須具有高深寬比(Aspect ratio)的鋁光柵結構，而本鑲入式奈米結構亦可應用於十字堆疊結構(Cross stacking structure)，以解決製作高深寬比結構時的對位(Alignment)問題。另一方面，藉由簡單的氧電漿製程，適當延長高分子材料蝕刻的時間，就能製作出雙層結構，增加其消光比(extinction ratio)，也能提升該偏光板的偏光效果。
此外，本論文中提出在介電質材料上製作具有銅金屬奈米線條的鑲入式奈米結構，經光學與電子學方面的實驗與量測證實，該結構具有透明電極的潛在應用價值。

關鍵詞：
鑲入式奈米壓印技術、鑲入式奈米結構、雙層結構、透明電極、金屬光柵、偏極板、可撓性基板、十字堆疊結構

This research proposes a technique called insertion nanoimprint, which features transferring the metallic (in this thesis, we used Al/Cu) wire gratings fabricated on a silicon wafer into a dielectric (in this thesis, we used PMMA (PolyMethyl MethAcrylate)) substrate under appropriate temperature and pressure conditions. It is also an innovative process that integrates the reversal nanoimprint with conventional nanoimprint process, including transferring metallic structures and defining pattern, respectively. The proposed insertion nanoimprint possesses the advantages of being able to transfer stable metallic wire gratings directly into a polymeric substrate and offer flatly finished surface for subsequent processes, such as sealing and packaging. Furthermore, this technique can avoid the embedded nanostructure from damage due to contamination and stresses during packaging or transportation.
In addition, we proposed an efficient process to fabricate insertion structure, with which features manufacturing insertion structure inside PMMA substrate through only three steps, including nanoimprint, metal deposition and CMP process. Therefore, this proposed technique can construct a stable insertion structure continuously and simply for mass production.
As the pitch of metallic wire gratings of insertion structure reduces to less than a half of the wavelength of incident light, it offers polarizing function and can be used as a polarizer. To achieve high polarization, it must possess Al wire gratings of insertion structure with high aspect ratio. Insertion structure can be the solution with cross stacking structure as fabricating high aspect ratio Al wire gratings for avoiding alignment in stacking process. Besides, we proposed a bi-layered structure, which consists of an Al layer on the top and a PMMA layer at the bottom, to enhance the optical performance, such as extinction ratio, through extending the O2 plasma etching time.
Moreover, we fabricated an insertion structure with Cu wire grid inside PMMA substrate. After optical and electrical measurement, we demonstrate that this proposed structure has potential for being applied to transparent metal electrode.

Keywords：
Insertion nanoimprint, insertion structure, bi-layered structure, transparent metal electrode, metallic wire gratings, polarizer, flexible substrate, cross stacking structure

[1] S. Y. Chou, P. R. Krauss and P. J. Renstrom, 1995, “Imprint of Sub-25 nm Vias and Trenches in Polymers,” Applied Physics Letters, Vol. 67, No. 20, pp. 3314- 3116.
[2] M. D. Austin, H. Ge, W. Li, Z. Yu, D. Wasserman, S. A. Lyon and S. Y. Chou, 2004, “Fabrication of 5 nm Linewidth and 14 nm Pitch Features by Nanoimprint Lithography,” Applied Physics Letters, Vol. 84, No. 26, pp. 5299-5301.
[3] M. Colburn, S. Johnson, M. Stewart, S. Damle, T. Bailey, B. Choi, M. Wedlake, T. Michaslson, S. V. Sreenivasan, J. Ekerdt and C. G. Willson, 1999, “Step and Flash Imprint Lithography : An Alternative Approach to High Resolution Pattering,” Proc. SPIE, Vol. 3676, pp. 379-389.
[4] H. Tan, A. Gilbertson and S. Y. Chou, 1998, “Roller Nanoimprint Lithography,” Journal of Vacuum Science and Technology B, Vol. 16, No. 6, pp. 3926-3928.
[5] S. Y. Chou, C. Keimel and J. Gu, 2002, “Ultrafast and Direct Imprint of Nanostructures in Silicon,” Nature, Vol. 417, No. 6891, pp.835-837.
[6] X. D. Huang, L. R. Bao, X. Cheng, L. J. Guo, S. W. Peng and A. F. Lee, 2002, “Reversal Imprinting by Transferring Polymer from Mold to Substrate,” Journal of Vacuum Science and Technology B, Vol. 20, No. 6, pp. 2872-2876.
[7] A. N. Shipway, M. Lahav and I. Willner, 2000, “Nanostructured Gold Colloid Electrodes,” Advanced Materials, Vol. 12, No. 12, pp. 993-998.
[8] F. Favier, E. C. Walter, M. P. Zach, T. Benter and R. M. Penner, 2001, “Hydrogen Sensors and Switches from Electrodeposited Palladium Mesowire Arrays,” Science, Vol. 293, No. 5538, pp. 2227-2231.
[9] T. A. Taton, C. A. Mirkin and R. L. Letsinger, 2000, “Scanometric DNA Array Detection with Nanoparticle Probes,” Science, Vol. 289, No. 5485, pp. 1757-1760.
[10] G. Schider, J. R. Krenn, W. Gotschy, B. Lamprecht, H. Ditlbacher, A. Leitner and F. R. Aussenegg, 2001, “ Optical Properties of Ag and Au Nanowire Grating,” Journal of Applied Physics, Vol.90, No. 8, pp. 3825-3830.
[11] http://www.moxtek.com
[12] R. T. Perkins, D. P. Hansen, E. W. Gardner, J. M. Thorne and A. A. Robbins, 2000, “Broadband wire grid polarizer for the visible spectrum,” U. S. Patent 6122103.
[13] J. J. Wang, J. Deng, X. Deng, F. Liu, P. Sciortino, L. Chen, A. Nikolov and A. Graham, 2005, “Innovative High-Performance Nanowire-grid Polarizers and Integrated Isolators,” IEEE Journal of selected Topics in Quantum Electronics, Vol. 11, No. 1, pp. 241-252.
[14] S. W. Ahn, K. D. Lee, J. S. Kim, S. H. Lee, J. D. Park and P. W. Yoon, 2005, “Fabrication of Subwavelength Aluminum Wire Grating Using Nanoimprint Lithography and Reactive Ion Etching,” Microelectronic Engineering, Vol. 78-79, No. 1-4, pp. 314-318.
[15] S. W. Ahn, K. D. Lee, J. S. Kim, S. H. Kim, J. D. Park, S. H. Lee and P. W. Yoon, 2005, “ Fabrication of a 50 nm Half-pitch Wire Grating Polarizer Using Nanoimprint Lithography,” Nanotechnology, Vol. 16, No. 9, pp. 1874-1877.
[16] K. W. Chien and H. P. D. Shieh, 2004, “Design and Fabrication of an Integrated Polarized Light Guide for Liquid-Crystal-Display Illumination,” Applied Optics, Vol. 43, No. 9, pp. 1830-1834.
[17] J. Tao, Y. Chen, X. Zhao, A. Malik and Z. Cui, 2005, “Room Temperature Nanoimprint Lithography Using a Bilayer of HSQ/PMMA Resist Stack,” Microelectronic Engineering, Vol. 78-79, No. 1-4, pp. 665-669.
[18] S. Y. Hwang. H. Y. Jung, J. H. Jeong and H. Lee, 2009, “Fabrication of Nano-size Metal Patterns on Flexible Polyethylene-Terephthalate Substrate Using Bi-Layer Nanoimprint Lithography,” Thin Solid Films, Vol. 517, pp. 4104-4107.
[19] C. H. Chen and Y. C. Lee, 2007, “ Contacting Printing for Direct Metallic Pattern Transfer Based on Pulsed Infrared Laser Heating,” Journal of Micromechanics and Microengineering, Vol. 17, pp. 1252-1256.
[20] Y. Xia, M. Mrksich, E. Kim and G. M. Whitesides, 1995, “Microcontact Printing of Octadecylsiloxane on the Surface of Silicon Dioxide and Its Application in Microfabrication,” Journal of the American Chemistry Society, Vol. 117, pp. 9576-9577.
[21] C. Peng, B. L. Cardozo and S. W. Pang, 2008, “Three-Dimensional Metal Patterning Over Nanostructures by Reversal Imprint,” Journal of Vacuum Science and Technology B, Vol. 26, No. 2, pp. 632-635.
[22] S . W. Pang, T. Tamamura, M. Nakao, A. Ozawa and H. Masuda, 1998, “Direct Nano-Printing on Al Substrate Using a SiC Mold,” Journal of Vacuum Science and Technology B, Vol. 16, No. 3, pp. 1145-1149.
[23] K. A. Lister, S. Thoms, D. S. Macintyre, C. D. W. Wilkinson, J. M. R. Weaver and B. G. Casey, 2004, “Direct Imprint of Sub-10 nm Features into Metal Using Diamond and SiC stamps,” Journal of Vacuum Science and Technology B, Vol. 22, No. 6, pp. 3257-3259.
[24] H. L. Chen, S. Y. Chuang, H. C. Cheng, C. H. Lin and T. C. Chu, 2006, “Directly Patterning Metal Films by Nanoimprint Lithography with Low-Temperature and Low-Pressure,” Microelectronic Engineering, Vol. 83, No. 4-9, pp. 893-896.
[25] M. G. Jang, M. S. Kim, J. Kim and L. J. Guo, 2008, “Organic Solar Cells Using Nanoimprinted Transparent Metal Electrodes,” Advanced Materials, Vol. 20, pp. 4408-4413.
[26] M. G. Kang and L. J. Guo, 2007, “Nanoimprinted Semitransparent Metal Electrodes and Their Application in Organic Light-Emitting Diodes,” Advanced Materials, Vol. 00, pp. 1-6.
[27] C. H. Chen, P. C. Chen and C. C. Chen, 2009, “High Extinction Ratio Polarized Light Guide with Layered Cross Stacking Nanostructure,” Microelectronic Engineering, Vol. 86, pp. 1107-1110.
[28] Hong Xiao, “Introduction to Semiconductor Manufacturing Technology,” PEARSON
[29] IBTS, Industrial Bank of Taiwan Securities.
[30] Lohstroh W, Felcher GP, Goyette R, Munzenberg M and Felsch W, 1999, “Imprinted Spiral Structures as Neutron Polarizers,” Physica B-Condensed Matter, Vol. 267, pp. 352-354.
[31] Z. Yu, W. Wu, L. Chen and S. Y. Chou, 2001, “Fabrication of Large Area 100 nm Pitch Grating by Spatial Frequency Doubling and Nanoimprint Lithography for Subwavelength Optical Applications,” Journal of Vacuum Science & Technology B, Vol. 19, pp. 2816-2819.
[32] B. Schnabel, E. Kley and F. Wyrowski, 1999, “Study on Polarizing Visible Light by Subwavelength-Period Metal-Stripe Gratings,” Optical Engineering, Vol. 38, pp.220-226.
[33] M. G. Kang, M. S. Kim, J. Kim and L. J. Guo, 2008, “Organic Solar Cells Using Nanoimprinted Transparent Metal Electrodes,” Advanced Materials , Vol. 20, pp. 4408-4413.
[34] http://www.gsolver.com
[35] J. B. Young, H. A. Graham and E. W. Peterson, 1965, “Wire Grid Infrared Polarizer,” Applied Optics, Vol. 4, pp. 1023-1026.
[36] S. W. Ahn, K. D. Lee, J. S. Kim, S. H. Kim, J. D. Park, S. H. Lee and P. W. Yoon, 2005, “Fabrication of A 50 nm Half-Pitch Wire Grid Polarizer Using Nanoimprint Lithography,” Nanotechnology, Vol. 16, pp. 1874-1877.
[37] I. Moreno, J. J. Araiza and M. Avendano-Alejo, 2005 , “Thin-film spatial filters,” Optics letters, Vol. 30, Issue. 8, pp. 914- 916.
[38] C. C. Chen and C. H. Chen, 2009, “Polarization Property of Light Guide Surface with Bilayered Nanostructure,” Optical Review, Vol. 16, No. 4, pp. 416- 421.
[39] K. W. Chien and H. P. D. Shieh, 2004, “Design and fabrication of an integrated polarized light guide for liquid-crystal-display illumination,” Applied Optics, Vol. 43, No. 9, pp. 1830-1834.
[40] C. M. Chen and C. K. Sung, 2010, “Fabricating Metallic Wire Grating Inside A Polymeric Substrate by Insertion Nanoimprint,” Microelectronic Engineering, Vol. 87, pp. 872-875.
[41] C. M. Chen, T. P. An, Y. M. Hung and C. K. Sung, 2011, “Fabricating insertion structures for metallic wire grid polarizers by nanoimprint and CMP process,” Microelectronic Engineering, Vol. 88, pp. 2135-2140.
[42] Z. Yu, P. Deshpande, W. Wu, J. Wang and S.Y. Chou, 2000, “Reflective Polarizer Based on A Stacked Double-Layer Subwavelength Metal Grating Structure Fabricated Using Nanoimprint Lithography,” Applied Physics Letters, Vol. 77, pp. 927-929.
[43] C.W. Hsieh, H.Y. Hsiung, Y.T. Lu, C.K. Sung and W.H. Wang, 2007, “Fabrication of Subwavelength Metallic Structures by Using A Metal Direct Imprinting Process,” Journal of Physics D-applied Physics, Vol. 40, pp. 3440-3447.
[44] M.C. Cheng, H.Y. Hsiung, Y.T. Lu and C.K. Sung,, 2007, “The Effect of Metal-Film Thickness on Pattern Formation by Using Direct Imprint,” Japanese Journal of Applied Physics, Vol. 46, pp. 6382-6386.
[45] X. D. Huang, L. R. Bao, X. Cheng, L. J. Guo, S. W. Pang and A. F. Lee, 2002, “Reversal Imprinting by Transferring Polymer from Mold to Substrate,” Journal of Vacuum Science and Technology B, Vol. 20, pp. 2872-2876.
[46] B. Schnabel, E. Kley and F. Wyrowski, 1999, “Study on Polarizing Visible Light by Subwavelength-Period Metal-Stripe Gratings,” Optical Engineering, Vol. 38, pp. 220-226.
[47] C. Y. Cheng and C. N. Hong, 2006, “Fabrication of Organic Light-Emitting Diode Arrays on Flexible Plastic Substrates by Imprint Lithography,” Japanese Journal of Applied Physics, Vol. 45, pp. 8915-8919.
[48] E. M. Park, J. Choi, B. H. Kang, K. Y. Dong, Y Park, I. S. Song and B. K. Ju, 2011, “Investigation of the effects of bottom anti-reflective coating on nanoscale patterns by laser interference lithography,” Thin Solid Films, Vol. 519, pp. 4220-4224.
[49] D. Amrani and P.Paradis, 2009, “Malus’s law of light polarization using a computer-based laboratory,” Journal Physics Education, Vol. 3, No. 2, pp. 229-231.
[50] W. S. Jahng, A. H. Francis, H. Moon, J. I. Nanos, and M. D. Curtis, 2006, “Is indium tin oxide a suitable electrode in organic solar cells? Photovoltaic properties of interfaces in organic p/n junction photodiodes,” Applied Physics Letters, Vol. 88, Issue 9, pp. 093504 - 093504-3.
[51] Z. Chen, B. Cotterell, W. Wang, E. Guenther, and S.-J. Chua, 2001, “A mechanical assessment of flexible optoelectronic devices,” Thin Solid Films, Vol. 394, Issue 1-2, pp. 201- 205.