臺灣博碩士論文加值系統

近年有很多文獻提到利用MFI沸石溶液作為塗佈液體，製作超低介電常數薄膜。雖然可做出介電常數大約2左右的薄膜，但其表面卻有不平整的現象。本研究在MFI沸石溶液中添加聚氧化乙烯型界面活性劑 (Tween80、Tween60、Tween40、Tween20)以解決表面不平整的問題，而且可以增加薄膜之中孔洞體積以進一步降低介電常數，所加入界面活性劑/ 四乙基矽的比例為0.41。本研究是以24小時水熱時間之小沸石晶種溶液及42小時水熱時間製作的大沸石結晶溶液為基礎，研究不同的聚氧化乙烯型界面活性劑對塗佈溶液的影響，以及對薄膜性質的影響。研究中並以氮氣吸脫附法量測孔洞體積及孔徑分佈，以了解這些界面活性劑對相關性質的影響。
由實驗結果發現，在塗佈溶液中加入Tween80所製作出來的薄膜有最低的介電常數值以及最高的機械強度 (Elastic modulus, hardness)。氮氣吸脫附實驗結果顯示孔洞體積和所加入的界面活性劑的分子大小有關係；加入的界面活性劑分子愈大，孔洞體積也愈大。然而，薄膜的介電常數值並不隨著孔洞體積的大小而變化。在實驗結果中，孔洞體積較大的薄膜，所製成薄膜的介電常數值較高；而孔洞體積較小的薄膜，反而有較低的介電常數值。本研究以TGA/ DTA量測來討論加入不同界面活性劑塗佈溶液中的氫氧基團和界面活性劑的分子或微胞之間的作用力。結果顯示這些作用力會影響氫氧基團與微胞在塗佈溶液中的位置，若是這些氫氧基團分佈在距離孔洞較遠的位置，會較難完全被修飾成疏水基團，而使薄膜有較高的介電常數值；相反的，若是氫氧基團分佈在較好修飾的位置，則薄膜會有相對較低的介電常數值。
薄膜的機械強度也會被氫氧基團和界面活性劑的分子或微胞之間的作用力所影響。從固態核磁共振儀 (29Si solid state NMR) 的結果顯示，在加入界面活性劑後的攪拌時，較強的作用力會限制氫氧基團的聚合反應，因此在薄膜鍛燒的時候，顆粒和顆粒之間會有較多的氫氧基團進行聚合反應，所以薄膜會有相對較高的機械強度。
本研究中以聚氧化乙烯型界面活性劑為模板試劑所製做的薄膜都符合IC工業的基本需求；介電常數值小於2或是2左右，彈性模數大於10 GPa且硬度大於1 GPa，漏電流也符合低於10-7 (A/cm2)的需求。

The synthesis of coating solutions with pure-silica-zeolite (PSZ) of MFI structure for low-k (dielectric constant) films applications was reported a few years ago. Although the k values can be around 2, the morphology of the films was poor. In order to solve this problem and to increase the mesopore volume in the films, the poly (ethylene oxide)-based non-ionic surfactants (such as Tween80, Tween60, Tween40 and Tween20) were added in the coating solution (with PSZ and MFI structure) in this research. The weight ratio of surfactant to tetraethylorthosilicate (TEOS, a silicon source) is 0.41. Two types of coating solutions with small crystalline particles or with large crystalline particles prepared through hydrothermal process were studied. The physical properties (dielectric constant, elastic modulus and harness) of the low-k films were characterized to make a comparison. Moreover, by burning away Tween in the films, the mesopores formed and the pore volume in the films should be increased, which may lower the k values of the films. Therefore, the nitrogen adsorption/ desorption measurements on different films were carried out at 77 K to characterize the effect of different Tweens on the pore volume and pore sizes in the low-k films.
It was found in this research that the films synthesized with the addition of Tween80 had the lower k value and the higher mechanical strength (Elastic modulus and hardness), as compared with those prepared with the addition of the other types of Tween. Nitrogen adsorption/ desorption results indicate that the total pore volume is consistent with the molecular size of Tween; in other words, a larger molecular size of Tween possesses a higher total pore volume. However, the dielectric constants are not consistent with the porosity (total pore volume) variation of the low-k films. In order to address the phenomena, TGA/ DTA results were provided to study the interaction between hydroxyl groups and surfactant molecules or surfactant micelles in the coating solutions. The results suggest that the interaction result in that the hydroxyl groups would be located in the position where is hard to be modified to become hydrophobic after the surfactant were removed. Therefore, the k values would be influenced.
The mechanical strength was also affected by the interactions between hydroxyl groups and the surfactant. From the results of 29Si solid state NMR spectra, a higher interaction would limit the polycondension reaction between hydroxyl groups during the stirring step. As a result, the low-k films would have a more completed polycondensation reaction among the hydroxyl groups after the calcinations, and the low-k film possessed a higher mechanical strength.
All of the low-k films synthesized with the addition of poly (ethylene oxide)-based surfactant met the requirements of IC industry; the low-k value were lower than 2 or around 2, elastic modulus were of > 10 GPa and hardness were of > 1 Gpa, and the values of leakage current density were under the order of 10-7 (A/cm2).

摘要 I
Abstract III
Contents V
Contents of Figures X
Contents of Tables XIV
Chapter 1 Introduction 1
1-1 Background 1
1-2 Classification of low-k materials 2
1-2.1 Organic polymer based dielectrics 3
1-2.2 Silsesquioxane based dielectrics 3
1-2.3 Silica based dielectrics 4
1-3 Porous silica low-k dielectrics 7
1-3.1 Surfactant-templated method 9
1-3.1.1 Mechanism of preparing porous/ mesostructure materials through surfactant-templated method 11
1-3.1.2 Application of mesostructure materials 12
1-3.1.3 Mesoporous silica low-k dielectrics 13
1-3.2 Hydrothermal method 16
1-4 Molecular structure and physical properties of poly (ethylene oxide)-based surfactants 20
1-5 Objective of this research 24
Chapter 2 Experimental 28
2-1 Chemicals 28
2-2 Apparatuses 29
2-3 General processes for the pretreatment of substrates and the preparation of low-k films 30
2-3.1 Cleaning substrates 30
2-3.2 Preparation of coating solutions and low-k films 31
2-4 Characterizations 33
2-4.1 Nitrogen adsorption/ desorption measurements 33
2-4.2 Solid-State NMR characterization 34
2-4.3 Inductively Coupled Plasma Optical Emission Spectrometry (ICP) characterization 34
2-4.4 Thermogravimetric analysis/ differential thermal analysis (TGA/ DTA) characterization 34
2-4.5 Characterization of low-k films 35
2-4.5.1 Dielectric constant measurement 36
2-4.5.2 Leakage current density measurement 37
2-4.5.3 Film thickness measurement 37
2-4.5.4 Mechanical strength measurement 38
Chapter 3 Results and Discussion 40
3-1 Physical parameters of PSZ MFI low-k films synthesized with different poly (ethylene oxide)-based surfactants 40
3-2 Discussions of low-k films synthesized with Tween80 and Tween60 surfactants 45
3-2.1 Comparison of the k values between different low-k films synthesized with Tween80 and Tween60 46
3-2.1.1 Analysis of nitrogen adsorption/ desorption and pore size distribution on the pores in the low-k films (Tween80 and Tween60) 47
3-2.1.2 Thermogravimetric analysis/ differential thermal analysis (TGA/ DTA) for the as-synthesized samples with Tween80 and without Tween80 53
3-2.1.3 Thermogravimetric analysis/ differential thermal analysis (TGA/ DTA) for the as-synthesized samples with different Tweens (Tween80 and Tween60) 58
3-2.1.4 Effects of Tween80 and Tween60 surfactants on k values of PSZ low-k films 62
3-2.2 Comparison of the mechanical strength between different low-k films synthesized with Tween80 and Tween60 66
3-3 Discussions of low-k films synthesized with Tween60 and Tween40 and Tween20 surfactants 72
3-3.1 Comparison of the k values between different low-k films synthesized with Tween60 and Tween40 and Tween20 73
3-3.1.1 Analysis of nitrogen adsorption/ desorption and pore size distribution on the pores in the low-k films (Tween60 and Tween40 and Tween20) 74
3-3.1.2 Thermogravimetric and N2 adsorption/ desorption analysis for mesoporous silica synthesized with a poly (ethylene oxide)-based surfactant on literature 82
3-3.1.3 Thermogravimetric analysis/ differential thermal analysis (TGA/ DTA) for the as-synthesized samples with different Tweens (Tween60 and Tween40 and Tween20) 84

3-3.1.4 Effects of Tween60 and Tween40 and Tween20 surfactants on k values of PSZ MFI low-k films 90
3-3.2 Comparison of the mechanical strengths between different low-k films synthesized with Tween60 and Tween40 and Tween20 93
Chapter 4 Conclusions 96
References 100

[1]H. Deligianni, "Future Directions in Electrochemical Technology on Semiconductor Chips," The Electrochemical Society, p. 1303, 2005.
[2]W. W. Lee and P. S. Ho, "Low-Dielectric-Constant Materials for ULSI Interlayer-Dielectric Applications," MRS Bulletin, vol. 22, pp. 19-23, 1997.
[3]ITRS, "The International Technology Roadmap for Semiconductors," 2008.
[4]K. Maex, M. R. Baklanov, D. Shamiryan, F. Iacopi, S. H. Brongersma, and Z. S. Yanovitskaya, "Low dielectric constant materials for microelectronics," Journal of Applied Physics, vol. 93, pp. 8793-8841, 2003.
[5]G. Maier, "Low dielectric constant polymers for microelectronics," Progress in Polymer Science, vol. 26, pp. 3-65, 2001.
[6]S. M. Yun, H. Y. Chang, M. S. Kang, and C. K. Choi, "Low dielectric constant CF/SiOF composite film deposition in a helicon plasma reactor," Thin Solid Films, vol. 341, pp. 109-111, 1999.
[7]S. J. Martin, J. P. Godschalx, M. E. Mills, E. O. Shaffer, and P. H. Townsend, "Development of a low-dielectric-constant polymer for the fabrication of integrated circuit interconnect," Advanced Materials, vol. 12, pp. 1769-1778, 2000.
[8]P. J. Bruinsma, N. J. Hess, and J. R. Bontha, "Low-k Mesoporous Silica Films Through Template-Based Processing " Materials Research Society Symposium Proceedings, vol. 443, p. 105, 1997.
[9]Q. S. Huo, D. I. Margolese, U. Ciesla, P. Y. Feng, T. E. Gier, P. Sieger, R. Leon, P. M. Petroff, F. Schuth, and G. D. Stucky, "Generalized Synthesis of Periodic Surfactant Inorganic Composite-materials," Nature, vol. 368, pp. 317-321, 1994.
[10]A. T. Kohl, R. Mimna, R. Shick, L. Rhodes, Z. L. Wang, and P. A. Kohl, "Low k, porous methyl silsesquioxane and spin-on-glass," Electrochemical and Solid State Letters, vol. 2, pp. 77-79, 1999.
[11]C. J. Brinker, G. W. Scherer, and C. J. Brinker, Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing Book Description, 1990.
[12]S. S. Prakash, C. J. Brinker, and A. J. Hurd, "Silica Aerogel Films At Ambient-pressure," Journal of Non-Crystalline Solids, vol. 190, pp. 264-275, 1995.
[13]M. T. Anderson, P. S. Sawyer, and T. Rieker, "Surfactant-templated silica aerogels," Microporous and Mesoporous Materials, vol. 20, pp. 53-65, 1998.

[14]T. Ramos, K. Roderick, and A. Maskara, "Nanoporous Silica for Low K Dielectrics," Materials Research Society Symposium Proceedings, vol. 443, p. 91, 1997.
[15]M. H. Jo, H. H. Park, D. J. Kim, S. H. Hyun, S. Y. Choi, and J. T. Paik, "SiO2 aerogel film as a novel intermetal dielectric," Journal of Applied Physics, vol. 82, pp. 1299-1304, 1997.
[16]C. Y. Ting, C. A. Wu, B. Z. Wan, and W. F. Wu, "Low dielectric constant silica films prepared by a templating method," Journal of the Chinese Institute of Chemical Engineers, vol. 34, pp. 211-217, 2003.
[17]C. J. Brinker, Y. F. Lu, A. Sellinger, and H. Y. Fan, "Evaporation-induced self-assembly: Nanostructures made easy," Advanced Materials, vol. 11, p. 579, 1999.
[18]J. S. Beck, J. C. Vartuli, W. J. Roth, M. E. Leonowicz, C. T. Kresge, K. D. Schmitt, C. T. W. Chu, D. H. Olson, E. W. Sheppard, S. B. McCullen, J. B. Higgins, and J. L. Schlenker, "A New Family of Mesoporous Molecular-sieves Prepared With Liquid-crystal Templates," Journal of the American Chemical Society, vol. 114, pp. 10834-10843, 1992.
[19]C. T. Kresge, M. E. Leonowicz, W. J. Roth, J. C. Vartuli, and J. S. Beck, "Ordered Mesoporous Molecular-sieves Synthesized By A Liquid-crystal Template Mechanism," Nature, vol. 359, pp. 710-712, 1992.
[20]H. Yang, A. Kuperman, N. Coombs, S. MamicheAfara, and G. A. Ozin, "Synthesis of oriented films of mesoporous silica on mica," Nature, vol. 379, pp. 703-705, 1996.
[21]H. Yang, N. Coombs, I. Sokolov, and G. A. Ozin, "Free-standing and oriented mesoporous silica films grown at the air–water interface " Nature, vol. 381, p. 589, 1996.
[22]I. A. Aksay, M. Trau, S. Manne, I. Honma, N. Yao, L. Zhou, P. Fenter, P. M. Eisenberger, and S. M. Gruner, "Biomimetic pathways for assembling inorganic thin films," Science, vol. 273, pp. 892-898, 1996.
[23]H. Yang, N. Coombs, I. Sokolov, and G. A. Ozin, "Registered growth of mesoporous silica films on graphite," Journal of Materials Chemistry, vol. 7, pp. 1285-1290, 1997.
[24]H. Yang, G. Vovk, N. Coombs, I. Sokolov, and G. A. Ozin, "Synthesis of mesoporous silica spheres under quiescent aqueous acidic conditions," Journal of Materials Chemistry, vol. 8, pp. 743-750, 1998.


[25]S. M. Yang, H. Yang, N. Coombs, I. Sokolov, C. T. Kresge, and G. A. Ozin, "Morphokinetics: Growth of mesoporous silica curved shapes," Advanced Materials, vol. 11, pp. 52-55, 1999.
[26]S. M. Yang, I. Sokolov, N. Coombs, C. T. Kresge, and G. A. Ozin, "Formation of hollow helicoids in mesoporous silica: Supramolecular Origami," Advanced Materials, vol. 11, pp. 1427-1431, 1999.
[27]M. Ogawa, "A simple sol-gel route for the preparation of silica-surfactant mesostructured materials," Chemical Communications, pp. 1149-1150, 1996.
[28]H. T. Hsu, C. Y. Ting, C. Y. Mou, and B. Z. Wan, "Nanoporous SiO2 films prepared by surfactant templating method - a novel antireflective coating technology," Nanotechnology in Mesostructured Materials, vol. 146, pp. 539-542, 2003.
[29]B. J. Scott, G. Wirnsberger, and G. D. Stucky, "Mesoporous and mesostructured materials for optical applications," Chemistry of Materials, vol. 13, pp. 3140-3150, 2001.
[30]G. Wirnsberger, P. D. Yang, B. J. Scott, B. F. Chmelka, and G. D. Stucky, "Mesostructured materials for optical applications: from low-k dielectrics to sensors and lasers," Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, vol. 57, pp. 2049-2060, 2001.
[31]R. Vogel, P. Meredith, I. Kartini, M. Harvey, J. D. Riches, A. Bishop, N. Heckenberg, M. Trau, and H. Rubinsztein-Dunlop, "Mesostructured dye-doped titanium dioxide for micro-optoelectronic applications," Chemphyschem, vol. 4, pp. 595-603, 2003.
[32]T. Yamada, H. S. Zhou, H. Uchida, M. Tomita, Y. Ueno, I. Honma, K. Asai, and T. Katsube, "Application of a cubic-like mesoporous silica film to a surface photovoltage gas sensing system," Microporous and Mesoporous Materials, vol. 54, pp. 269-276, 2002.
[33]T. Yamada, H. S. Zhou, H. Uchida, M. Tomita, Y. Ueno, T. Ichino, I. Honma, K. Asai, and T. Katsube, "Surface photovoltage NO gas sensor with properties dependent on the structure of the self-ordered mesoporous silicate film," Advanced Materials, vol. 14, pp. 812-815, 2002.
[34]B. Yuliarto, H. Zhou, T. Yamada, I. Honma, and K. Asai, "The SPV NO2 Gas Sensor Fabricated by Mesoporous Tin Oxide Film," Chemistry Letters, vol. 32, p. 510, 2003.



[35]S. Dai, M. C. Burleigh, Y. H. Ju, H. J. Gao, J. S. Lin, S. J. Pennycook, C. E. Barnes, and Z. L. Xue, "Hierarchically imprinted sorbents for the separation of metal ions," Journal of the American Chemical Society, vol. 122, pp. 992-993, 2000.
[36]M. C. Burleigh, S. Dai, E. W. Hagaman, and J. S. Lin, "Imprinted polysilsesquioxanes for the enhanced recognition of metal ions," Chemistry of Materials, vol. 13, pp. 2537-2546, 2001.
[37]A. Kucernak and J. H. Jiang, "Mesoporous platinum as a catalyst for oxygen electroreduction and methanol electrooxidation," Chemical Engineering Journal, vol. 93, pp. 81-90, 2003.
[38]S. Baskaran, J. Liu, K. Domansky, N. Kohler, and X. Li, "Low Dielectric Constant Mesoporous Silica Films Through Molecularly Templated Synthesis " Advanced Materials, vol. 12, pp. 291-294, 2000.
[39]C. M. Yang, A. T. Cho, F. M. Pan, T. G. Tsai, and K. J. Chao, "Spin-on mesoporous silica films with ultralow dielectric constants, ordered pore structures, and hydrophobic surfaces," Advanced Materials, vol. 13, p. 1099, 2001.
[40]C. Y. Ting, D. F. Ouyan, and B. Z. Wan, "Preparation of ultralow dielectric-constant porous silica films using Tween 80 as a template," Journal of the Electrochemical Society, vol. 150, pp. F164-F167, 2003.
[41]C. Y. Ting, D. F. Ouyan, W. F. Wu, and B. Z. Wan, "Template effects on low k materials made from spin-on mesoporous silica," in Nanotechnology in Mesostructured Materials, 2003, pp. 391-394.
[42]S. B. Jung, C. K. Han, and H. H. Park, "Electrical and mechanical properties of surfactant-templated mesoporous silica thin films using Brij-76 surfactant," Applied Surface Science, vol. 244, pp. 47-50, 2005.
[43]P. J. Bruinsma, J. R. Bontha, J. Liu, and S. Baskaran, "Mesoporous-silica films, fibers, and powders by evaporation " U.S. Patent No. 5 922 299, 1999.
[44]D. Zhao, P. Yang, N. Melosh, J. Feng, B. F. Chmelka, and G. D. Stucky, "Continuous mesoporous silica films with highly ordered large pore structures," Advanced Materials, vol. 10, p. 1380, 1998.
[45]C.-Y. Ting, D.-F. Ouyan, and B.-Z. Wan, "Proceedings of the 3rd International Mesostructured Materials Symposium, Jeju, Korea," Nanotechnology in Mesostructured Materials, vol. 146, pp. 146-147, 2002.
[46]S. B. Jung and H. H. Park, "Concentration-dependent mesostructure of surfactant-templated mesoporous silica thin film," Thin Solid Films, vol. 494, pp. 320-324, 2006.
[47]C. Y. Ting, H. S. Sheu, W. F. Wu, and B. Z. Wan, "Porosity effects on properties of mesoporous silica low-k films prepared using tetraethylorthosilicate with different templates," Journal of the Electrochemical Society, vol. 154, pp. G1-G5, 2007.
[48]C. T. Tsai, H. Y. Lu, C. Y. Ting, W. F. Wu, and B. Z. Wan, "Increasing mechanical strength of mesoporous silica thin films by addition of tetrapropylammonium hydroxide and refluxing processes," Thin Solid Films, vol. 517, pp. 2039-2043, 2009.
[49]Z. B. Wang, H. T. Wang, A. Mitra, L. M. Huang, and Y. S. Yan, "Pure-silica zeolite low-k dielectric thin films," Advanced Materials, vol. 13, pp. 746-749, 2001.
[50]Z. B. Wang, A. P. Mitra, H. T. Wang, L. M. Huang, and Y. S. Yan, "Pure silica zeolite films as low-k dielectrics by spin-on of nanoparticle suspensions," Advanced Materials, vol. 13, p. 1463, 2001.
[51]S. Li, Z. J. Li, and Y. S. Yan, "Ultra-low-k pure-silica zeolite MFI films using cyclodextrin as porogen," Advanced Materials, vol. 15, p. 1528, 2003.
[52]Z. J. Li, S. Li, H. M. Luo, and Y. S. Yan, "Effects of crystallinity in spin-on pure-silica-zeolite MFI low-dielectric-constant films," Advanced Functional Materials, vol. 14, pp. 1019-1024, 2004.
[53]S. Eslava, C. E. A. Kirschhock, S. Aldea, M. R. Baklanov, F. Iacopi, K. Maex, and J. A. Martens, "Characterization of spin-on zeolite films prepared from Silicalite-1 nanoparticle suspensions," Microporous and Mesoporous Materials, vol. 118, pp. 458-466, 2009.
[54]S. Eslava, M. R. Baklanov, A. V. Neimark, F. Iacopi, C. E. A. Kirschhock, K. Maex, and J. A. Martens, "Evidence of large voids in pure-silica-zeolite low-k dielectrics synthesized by spin-on of nanoparticle suspensions," Advanced Materials, vol. 20, pp. 3110-3116, 2008.
[55]M. H. Ree, J. W. Yoon, and K. Y. Heo, "Imprinting well-controlled closed-nanopores in spin-on polymeric dielectric thin films," Journal of Materials Chemistry, vol. 16, pp. 685-697, 2006.
[56]M. Johnson, Z. J. Li, J. L. Wang, and Y. S. Yan, "Mechanical characterization of zeolite low dielectric constant thin films by nanoindentation," Thin Solid Films, vol. 515, pp. 3164-3170, 2007.
[57]N. Hata, G. Guan, T. Yoshino, and S. Takada, "Zeolite Nano-crystal Suspension, Zeolite Nano-crystal Production Method, Zeolite Nano-crystal Suspension Production Method, And Zeolite Thin Film," U.S. Patent No. US007384622B2, 2008.
[58]T. Yoshino, N. Ohnuki, N. Hata, and Y. Seino, "Young''s Modulus Enhancement of Mesoporous Pure-Silica–Zeolite Low-Dielectric-Constant Films by Ultraviolet and Silylation Treatments," Japanese Journal of Applied Physics, vol. 48, pp. 0502101 - 052103, 2009.
[59]T. Seo, T. Yoshino, N. Ohnuki, Y. Seino, Y. Cho, N. Hata, and T. Kikkawa, "Effect of Silylation Hardening on the Electrical Characteristics of Mesoporous Pure Silica Zeolite Film," Journal of the Electrochemical Society, vol. 156, pp. H98-H105, 2009.
[60]T. Seo, T. Yoshino, Y. Cho, N. Hate, and T. Kikkaw, "Electrical Characteristics of Mesoporous Pure-Silica–Zeolite Film," Japanese Journal of Applied Physics, vol. 46, pp. 5742–5746, 2007.
[61]柳佑樵, "探討不同型態二氧化矽粒子及大小對孔洞型低介電薄膜的影響," 化學工程學研究所, 國立台灣大學, 2006.
[62]游竣偉, "製備程序的變因對於低介電孔洞型二氧化矽薄膜性質的影響," 化學工程學研究所, 國立台灣大學, 2007.
[63]鄧志霖, "探討製程對結晶性孔洞型二氧化矽薄膜性質的影響," 化學工程學研究所, 國立台灣大學, 2008.
[64]龔建豪, "鹼式單階段水熱製程製備結晶孔洞型二氧化矽低介電薄膜," 化學工程學研究所, 國立台灣大學, 2009.
[65]E. P. Barrett, L. G. Joyner, and P. P. Halenda, "The Determination of Pore Volume and Area Distributions in Porous Substances. I. Computations from Nitrogen Isotherms," Journal of the American Chemical Society, vol. 73, p. 1951, 1951.
[66]Y. C. Hsu, Y. T. Hsu, H. Y. Hsu, and C. M. Yang, "Facile synthesis of mesoporous silica SBA-15 with additional intra-particle porosities," Chemistry of Materials, vol. 19, pp. 1120-1126, 2007.
[67]Y. T. Hsu, W. L. Chen, and C. M. Yang, "Co-Condensation Synthesis of Aminopropyl-Functionalized KIT-5 Mesophases Using Carboxy-Terminated Triblock Copolymer," Journal of Physical Chemistry C, vol. 113, pp. 2777-2783, 2009.
[68]X. D. Li and B. Bhushan, "A review of nanoindentation continuous stiffness measurement technique and its applications," Materials Characterization, vol. 48, pp. 11-36, 2002.
[69]L. Sierra, B. Lopez, H. Gil, and J. L. Guth, "Synthesis of mesoporous silica from sodium silica solutions and a poly(ethylene oxide)-based surfactant," Advanced Materials, vol. 11, pp. 307-311, 1999.