臺灣博碩士論文加值系統

摘要
為了改善發光二極體的光萃取效率，許多方法已被提出，這其中又以圖案化藍寶石基板(Patterned Sapphire Substrates, PSS)最受青睞，因為PSS不僅可以提升光萃取效率亦可增加內部的量子效率。而如何製作符合高效率LED的PSS，又能減少製程時間是一項具有挑戰性的工作。本研究採用自行設計開發的紫外光輔助的滾輪式奈米壓印設備搭配乾蝕刻製程，來進行次微米結構PSS的壓印研究。
首先利用步進投影方式定義大面積的次微米矽母模仁的圖案，再以乾蝕刻完成模仁結構製作；之後探討壓印材料對於模具的親疏水性實驗以及脫模分析，進行複製凹凸相反的聚二甲基矽氧烷(polydimethyl siloxane, PDMS)可撓性的子模仁。接著進行初步壓印實驗，推斷產生缺陷現象的可能原因。再針對主要製程參數中的壓印壓力與壓印速度進行分析，進而改善製程提高良率。最後對700/500 nm(直徑/間距)洞狀結構進行全晶圓轉印實驗，分別製作出2吋、4吋、6吋的全晶圓壓印結果，以及利用乾式蝕刻製作出次微米級的圖案化藍寶石基板。

Abstract
Many methods had been proposed to improve the light extraction efficiency of the light emitting diodes (LEDs). Among these methods, patterned sapphire substrates (PSS) is the most promising technology since PSS not only can enhance the light extraction efficiency (LEE), but also improve the internal quantum efficiency (IQE). Moreover, how to fabricate PSS for high efficiency LED and also reduce the process time is a challenging task. This study used self-developed UV-assisted roller nanoimprinting equipment and dry etching to fabricate submicron PSS.
The submicron pattern of silicon molds was defined by a projection stepper, and etching structure was produced directly by dry etching. A soft polymer such as polydimethylsiloxane (PDMS) was used as a mold to duplicate the pattern of the silicon mold. Enhancing the hydrophobic of silicon and reducing the thickness of PDMS were useful to prepare PDMS molds. Imprinting processes were carried out to analyze the causes of imprinting defect, and imprinting pressure and speed are the two major parameters to influence the imprinting qualities. In this study, hole structure with 700 nm diameter and 500 nm spacing on 2-inch, 4-inch and 6-inch were successfully imprinted on sapphire substrates. The following dry etching process accomplish the fabrication submicron PSS.

目錄
摘要 I
Abstract II
誌謝 III
目錄 IV
表目錄 VII
圖目錄 VIII
第一章 序論 1
1-1 前言 1
1-2 研究背景 2
1-3 文獻回顧 4
1-3-1 圖案化藍寶石基板 4
1-3-2 奈米壓印成型技術 9
1-4 研究動機與論文簡介 12
第二章 實驗設備與方法 15
2-1 次微米壓印模仁製作 15
2-1-1次微米矽模仁製作 15
2-1-2 轉印次微米金屬模仁製作 20
2-1-3 PDMS軟性模仁製作 22
2-2 滾輪式奈米壓印設備 24
2-2-1 設計理念與流程 24
2-2-2機構設計 26
2-2-3 機構組立與測試 29
2-3 滾輪式紫外光壓印製程 32
2-4 乾蝕刻製作圖案化藍寶石基板 35
第三章 實驗結果與分析 37
3-1 次微米模仁製作分析 37
3-1-1 光罩圖形設計 37
3-1-2 次微米PDMS模仁製作分析 43
3-2滾輪式壓印製程與分析 51
3-2-1壓印實驗參數的建立與分析 51
3-2-2 全晶圓壓印製作分析 57
3-2-3 殘留層優化分析 61
3-3 圖案化藍寶石基板蝕刻結果 63
第四章 結論與未來展望 65
4-1 結論 65
4-2 未來與展望 66
參考文獻 67

表目錄
表3- 1不同溫度實驗參數表 44
表3- 2不同加熱時間實驗參數表 45
表3- 3塗佈PTFE與未塗佈PTFE至不同基板之接觸角 46
表3- 4壓力-速度參數對照表 52
表3- 5不同壓印速度之參數表 53
表3- 6不同壓印壓力之參數表 55
表3- 7全晶圓製程實驗參數表 60

圖目錄
圖1- 1 LED活性層出光受限於半導體材料之示意圖 3
圖1- 2 GaN磊晶層成長於(a) PSS與(b) PLSS基板之TEM剖面圖 6
圖1- 3 Planar-LED與PSS-LED光追蹤路線[18] 6
圖1- 4熱壓、紫外光固化以及軟性奈米壓印技術示意圖 10
圖2- 1次微米矽模仁製作流程與相對參數圖 19
圖2- 2次微米矽模仁製作流程示意圖 19
圖2- 3(a)次微米矽模仁SEM圖 (b)6吋矽模仁成品圖 20
圖2- 4次微米金屬模仁製作流程示意圖 21
圖2- 5次微米金屬模仁SEM圖 21
圖2- 6 PDMS模仁製作示意圖 22
圖2- 7真空裝置圖 23
圖2- 8 PDMS模仁SEM圖，(a)圓柱圖樣、(b)洞狀圖樣 24
圖2- 9傳動部件設計圖 26
圖2- 10真空平台外觀設計圖 27
圖2- 11滾輪部件機構設計圖 28
圖2- 12貼模部件機構設計圖 29
圖2- 13繪圖軟體製作機構組立圖 30
圖2- 14滾輪式奈米壓印設備機構系統設計圖 31
圖2- 15實際組立完成圖 31
圖2- 16感壓紙測試結果 32
圖2- 17壓印製程示意圖(a)正向壓印示意圖、(b)反向壓印示意圖 32
圖2- 18塗佈PDMS模仁後的實際圖 34
圖2- 19觸控式人機介面圖 34
圖2- 20漸進式貼合的示意圖 35
圖2- 21蝕刻藍寶石基板製程示意圖 36
圖3- 1最密六方排列示意圖 37
圖3- 2步進式曝光示意圖 38
圖3- 3光罩圖面 39
圖3- 4圓洞光罩設計圖 40
圖3- 5 700/500 nm線寬大小的SEM圖 40
圖3- 6接合處附近的OM圖 41
圖3- 7曝光後的實際圖 41
圖3- 8採用全圓的柱狀光罩設計示意圖 42
圖3- 9柱狀半圓光罩設計 42
圖3- 10柱狀半圓接合圖(a)OM圖、(b)SEM圖 43
圖3- 11不同溫度接觸角的比較圖 45
圖3- 12不同加熱時間接觸角的比較圖 46
圖3- 13不同厚度的PDMS模仁(a) 2mm、(b) 1.6mm、(c) 1.2mm 47
圖3- 14高度1400 nm的柱狀PDMS模仁 47
圖3- 15不同厚度脫模實際圖 48
圖3- 16機械強度不足的模仁圖 49
圖3- 17 PDMS模仁高度(a)800 nm、(b)1200 nm、(c)1400 nm 49
圖3- 18 (a)原本、(b)一次、(c)三次、(d)五次 50
圖3- 19 800 nm高度的6吋次微米PDMS模仁 50
圖3- 20實驗結果觀察圖(OM 1000X) 52
圖3- 21不同壓印速度的實驗結果圖(OM 1000X) 54
圖3- 22不同壓力的實驗結果圖(OM 1000X) 57
圖3- 23 500 rpm 與 3000 rpm塗佈結果比較圖 58
圖3- 24氣泡埋覆導致結構破壞圖 59
圖3- 25漸進式壓印成品圖 59
圖3- 26全晶圓壓印成品圖(a)2吋、(b)4吋、(c)6吋 60
圖3- 27 700/500 nm圓洞SEM圖 61
圖3- 28殘留阻劑圖 62
圖3- 29添加稀釋劑後的殘留層圖 62
圖3- 30塗佈缺陷圖 62
圖3- 31殘留層去除SEM 圖 64
圖3- 32蝕刻藍寶石基板SEM圖 64
圖3- 33次微米圖案化藍寶石基板(a)SEM圖、(b)2吋成品圖 64

參考文獻
[1]E. F. Schubert, 2006, “ Light-Emitting Diodes, second edition, Cambridge University Press”.
[2]C. F. Lin, Z. J. Yang, B. H. Chin, J. H. Zheng, J. J. Dai, B. C. Shieh and C. C. Chang, 2006, “Enhanced Light Output Power in InGaN Light-Emitting Diodes by Fabricating Inclined Undercut Structure”, Journal of The Electrochemical Society.
[3]S. C. Huang, D. S. Wuu , P. Y. Wu , W. Y. Lin , P. M. Tu, Y. C. Yeh, C. P. Hsu, S. H. Chan, 2009, “Improved output power of 400-nm InGaN/AlGaN LEDs using a novel surface roughening technique”, Journal of Crystal Growth.
[4]T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars and S. Nakamuraa, 2004, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening”, Applied Physics Letters, Vol. 84, No. 6, pp. 855–857.
[5]S. M. Jeong, S. Kissinger, D.W. Kim, S. J. Lee, J. S. Kim, H. K. Ahn, C. R. Lee, 2010, “Characteristic enhancement of the blue LED chip by the growth and fabrication on patterned sapphire (0 0 0 1) substrate”, Journal of Crystal Growth, Vol. 312, No. 2, pp. 258-262.
[6]D. H. Long, I. K. Hwang and S. W. Ryu, 2009, “Design Optimization of Photonic Crystal Structure for Improved Light Extraction of GaN LED”, IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, Vol. 15, No. 4, pp. 1257-1263.
[7]T. N. Oder, K. H. Kim, J. Y. Lin, H. X. Jiang, 2004, “III-nitride blue and ultraviolet photonic crystal light emitting diodes”, Applied Physics Letters, Vol. 84, No. 4, pp. 466-468.
[8]K. J. Byeon, S.Y. Hwang and H. Lee, 2007, “Fabrication of two-dimensional photonic crystal patterns on GaN-based light-emitting diodes using thermally curable monomer-based nanoimprint lithography”, Applied Physics Letters, Vol. 91, No. 9.
[9]P. Wang, Z. Gan, S. Liu, 2009, “Improved light extraction of GaN-based light-emitting diodes with surface-patterned ITO”, Optics &; Laser Technology, Vol. 41, No. 6, pp. 823-826.
[10]P. Wang, B. Cao, W. Wei, Z. Gan, S. Liu, 2010, “Improved light extraction of GaN-based light-emitting diodes by ITO patterning with optimization design”, Solid-State Electronics, Vol. 54, No. 3, pp. 283-287.
[11]O. H. Nam, M. D. Bremser, T. S. Zheleva and R. F. Davis, 1997, “Lateral epitaxy of low defect density GaN layers via organometallic vapor phase epitaxy”, Applied Physics Letters, Vol. 71, No. 18.
[12]W. Zhou, D. Ren, P. D. Dapkus, 2005, “Three-dimensional microstructural characterization of GaN nonplanar substrate laterally epitaxially overgrown by metalorganic chemical vapor deposition”, Journal of Crystal Growth, Vol. 283, No. 1-2, pp. 31-40.
[13]H. H. Huang, C. L. Chao, T. W. Chi, Y. L. Chang, P. C. Liu, L. W. Tu, J. D. Tsay, H.C. Kuo, S. J. Cheng, W. I. Lee, 2009, “Strain-reduced GaN thick-film grown by hydride vapor phase epitaxy utilizing dot air-bridged structure”, Journal of Crystal Growth, Vol. 311, No. 10, pp. 3029-3032.
[14]A. Ishibashi, I Kidoguchi, G. Sugahara, Y. Ban, 2000, “High-quality GaN films obtained by air-bridged lateral epitaxial growth”, Journal of Crystal Growth, Vol. 221, No. 1-4, pp. 338-344
[15]B. P. Wagner, Z. J. Reitmeier, J. S. Park, D. Bachelor, D. N. Zakharov, Z. L. W., R. F. Davis, 2006, “Growth and characterization of pendeo-epitaxial GaN(1 1 2 0) on 4H–SiC(1 1 2 0) substrates”, Journal of Crystal Growth, Vol. 290, No. 2, pp. 504-512.
[16]A. M. Roskowski, P. Q. Miraglia, E. A. Preble, S. Einfeldt, R. F. Davis, 2002, “Surface instability and associated roughness during conventional and pendeo-epitaxial growth of GaN(0 0 0 1) films via MOVPE”, Journal of Crystal Growth, Vol. 241, No. 1-2, pp. 141-150.
[17]莊文魁， 2008， “製作於圖形化藍寶石基板上的InGaN發光二極體之相關壽命測試及界面溫度量測分析”， 成大研發快訊 第三卷 第六期。
[18]H. Gao, F. Yan, Y. Zhang, J. Li, Y. Zeng and G. Wang, 2008, “Fabrication of nano-patterned sapphire substrates and their application to the improvement of the performance of GaN-based LEDs”, Journal of Physics D: Applied Physics, Vol. 41, No. 11.
[19]K. Tadatomo, H. Okagawa, Y. Ohuchi, T. Tsunekawa, T. Jyouichi, Y. Imada, M. Kato, H. Kudo, T. Taguchi, 2001, “High Output Power InGaN Ultraviolet Light-Emitting Diodes Fabricated on Patterned Substrates Using Metalorganic Vapor Phase Epitaxy”, Physica Status Solidi (a), Vol. 188, No. 1, pp. 121-125.
[20]S. J. KIM, 2005, “Vertical Electrode GaN-Based Light-Emitting Diode Fabricated by Selective Wet Etching Technique”, Japanese Journal of Applied Physics, Vol. 44, No. 5A, pp. 2921–2924.
[21]J. H. Lee, D.Y. Lee, B. W. Oh and J. H. Lee, 2010, “Comparison of InGaN-Based LEDs Grown on Conventional Sapphire and Cone-Shape-Patterned Sapphire Substrate”, IEEE Transactions on Electron Devices, Vol. 57, No. 1, pp. 157-163.
[22]J. H. Lee, J. T. Oh, Y. C. Kim, J. H. Lee, 2008, “Stress Reduction and Enhanced Extraction Efficiency of GaN-Based LED Grown on Cone-Shape-Patterned Sapphire”, Photonics Technology Letters, Vol. 20, No. 18, pp. 1563-1565.
[23]Y. K. Su, J. J. Chen, C. L. Lin, S. M. Chen, W. L. Li, C. C. Kao, 2009, “Pattern-size dependence of characteristics of nitride-based LEDs grown on patterned sapphire substrates”, Journal of Crystal Growth, Vol. 311, No. 10, pp. 2973-2976.
[24]H. Gao, F. Yan, Y. Zhang, J. Li, Y. Zeng and G. Wang, 2008, “Enhancement of the light output power of InGaN/GaN light-emitting diodes grown on pyramidal patterned sapphire substrates in the micro- and nanoscale”, Journal of Applied Physics, Vol. 103, No. 1.
[25]J. J. Chen, Y. K. Su, C. L. Lin, S. M. Chen, W. L. Li and C. C. Kao, 2008, “Enhanced Output Power of GaN-Based LEDs With Nano-Patterned Sapphire Substrates”, Photonics Technology Letters, Vol. 21, No. 13, pp. 1193-1195.
[26]F. Yan, H. Gao, Y. Zhang, J. Li, Y. Zeng, G. Wang, F. Yang, 2007, “High-efficiency GaN-based blue LEDs grown on nano-patterned sapphire substrates for solid-state lighting”, Semiconductor Lighting Technology Research and Development Center, Beijing, China.
[27]H. W. Huang, C. H. Lin, J. K. Huang, K. Y. Lee, C. F. Lin, C. C. Yu, J. Y. Tsai, R. Hsueh, H. C. Kuo, S. C.Wang, 2009, “Investigation of GaN-based light emitting diodes with nano-hole patterned sapphire substrate (NHPSS) by nano-imprint lithography”, Materials Science and Engineering: B.
[28]F. Y. Shih, A. Kobayashi, S. Inoue, J. Ohta, M. Oshima, H. Fujioka, 2011, “Growth of group III nitride nanostructures on nano-imprinted sapphire substrates”, Thin Solid Films, Vol. 519, No. 19.
[29]Y. T. Hsieh and Y. C. Lee, 2012, “Metal Contact Printing Photolithography for Fabricating Sub-Micrometer Patterned Sapphire
Substrates in Light-Emitting Diodes”, Nano/Micro Engineered and Molecular Systems, pp.40-44.
[30]S. Y. Chou, P. R. Krauss and P. J. Renstrom, 1995, “Imprintof sub-25 nm vias and trenches in polymers”, Applied Physics Letters, Vol. 67, No. 21, pp. 3114-3116.
[31]M. D. Austin, H. Ge, W. Wu, M. 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.
[32]M. Bender, M. Otto,B. Hadam, B. Vratzov, B. Spangenberg and H. Kurz, 2000, “Fabrication of nanostructures using a UV-based imprint technique”, Microelectron. Eng.,Vol. 53, pp. 233.
[33]Y. Xia and G. M. Whitesides, 1998, “Soft lithography”, Annu. Rev. Mater. Sci., Vol. 28, pp. 153.
[34]H. Tan, A. Gilbertson, S. Y. Chou, 1998, “Roller nanoimprint lithography”, J. Vac. Sci. Technol. B Vol. 16, pp. 3926.
[35]K. Nagato, S. Sugimoto, T. Hamaguchi, M. Nakao, 2010, “Iterative roller imprint of multilayered nanostructures”, Microelectronic Engineering, Vol. 87, No. 5-8, pp. 1543-1545.
[36]T. Makela, T. Haatainen, P. Majander, J. Ahopelto and V. Ambertini, 2008, “Continuous Double-Sided Roll-to-Roll Imprinting of Polymer Film”, Jpn. J. Appl. Phys., Vol. 47, pp.5142.
[37]J. J. Lee, S. Y. Park, K. B. Choi, G. H. Kim, 2008, “Nano-scale patterning using the roll typed UV-nanoimprint lithography tool”, Microelectron. Eng., Vol.85, pp. 861.
[38]吳祚享， 2010， “滾輪式奈米壓印設備與製程開發”， 中原大學 碩士學位論文。
[39]金文森， 2011， 材料力學， 高立出版社。