臺灣博碩士論文加值系統

論文研究低介電常數材料Hydrogen silsesquioxane (HSQ)於薄膜電晶體顯示器陣列技術上的應用。由於低介電常數材料(HSQ)應用於薄膜電晶體(TFT)元件上的平坦化保護層(planarized passivation layer)時，能夠提高薄膜電晶體顯示器的開口率(aperture ratio)，降低電晶體陣列連線中電阻-電容延遲時間(RC delay time)，並且對於矽和玻璃基板有良好的附著性，以及具有高透光率(>90% at300-800nm)、好的平坦化(planarization)能力、優異的縫隙填充(gap fill)能力。因此，低介電常數材料於薄膜電晶體顯示器上的研究與應用，便成為重要的顯示器技術發展趨勢。為了能將低介電常數材料整合於平面顯示器的製造過程，它必需具有好的熱穩定性和製程整合相容性。本論文選擇一種具有潛力的低介電常數材料，Hydrogen silsesquioxane (HSQ)做為研究主題。此外，也探討其於不同電漿處理及光源曝露時的電性傳導機制，以評估實際應用時所遇到的潛在問題。
HSQ是一種無機類的低介電常數材料，可利用旋塗的方式製作介電膜，其具有很好的填洞能力及製程比化學氣相沈積簡單的優點。HSQ的低介電常數特性主要因為其為低密度材料，而Si-H鍵的穩定性也決定HSQ膜的介電常數。在光電流的研究方面，由於一些不完全的懸垂鍵結(dangling bonds)會在HSQ薄膜的製作過程中形成，而使得少量的傳導載子會經由這些不完全的鍵結而產生，造成光電流的形成。不過，光電流的量會是在可接受的範圍內。至於在光阻去除過程中的氧電漿處理，我們發現氧電漿會使HSQ薄膜的漏電流上升一個數量級以上，這會使得HSQ薄膜的漏電流機制從蕭特基放射(Schottky emission)轉變成離子傳導(ionic condction) 為主宰的行為。由於這個增加的量太大，所以我們觀察不到微小的光電流的效應。因此，我們提出氫氣電漿前處理(pre-treatment)來改善薄膜的漏電特性。我們發現氫氣電漿可以有效的預防氧氣電漿對HSQ薄膜的傷害，而使得HSQ薄膜的漏電特性和標準的HSQ薄膜(as-cured HSQ)相似。這可能的原因是氫氣電漿可提供活性的氫原子將HSQ內的不完全鍵結覆蓋，而使氧氣電漿的破壞降到最低。
總結我們的研究的結果，我們發現由於HSQ薄膜對可見光的敏感性極低，因此，曝露在光源下時薄膜並不會產生太大的光電流。所以，將HSQ薄膜應用在薄膜電晶體驅動之顯示面板中的保護層(passivation layer)上，是具有很大的發展潛力的。

In this thesis, we investigated the application of low-dielectric-constant (low-k) hydrogen silsesquioxane (HSQ) for thin-film-transistor (TFT) arrary technology. The adoption of low-k HSQ for TFT passivation layer can effectively increase the aperture ratio of display matrix, reduce resistance-capacitance delay (RC delay), exhibiting high optical transparency (90% at 300-800nm), good planarization properties and excellent gap-filling capability. In this study we have investigated one of the promising candidates of low-k dielectrics, hydrogen silsesquioxane (HSQ), for TFT array technology application. The leakage current conduction mechanism in HSQ films after O2, H2/O2 plasma treatments and photo illumination will be discussed extensively.
In comparison with chemical vapor deposited (CVD) low-k materials, HSQ films can be deposited using spin-on process which is a simpler technique. The quality of the low-k HSQ film dependents on the residual quantity of the Si-H bonds in the film after curing. A low dielectric constant can be achieved if the Si-H bonds in the HSQ film outnumber the Si-OH bonds. For the investigation of photo-induced leakage current, we have found that dangling bonds are easy to be generated during the processing of the HSQ films; thereby, a small amount of photo-induced leakage current can be generated via these traps in HSQ films. Fortunately, the level of photo-induced leakage current is acceptable for TFT array applications. However, the leakage current of HSQ film is increased more than an order of magnitude after O2-plasma treatment during photoresist stripping, and the conduction mechanism for the leakage current transferring from Schottky emission to ionic conduction. In this work, we found that an hydrogen plasma treatment of the HSQ films can improve the films quality. The leakage current in HSQ films subjected to H2-plasma treatment is decreased. In this work, we have proposed a model to explain the role of the hydrogen in HSQ film. The hydrogen can effectively passivate the surface of HSQ film. If the surface is not passivaed by hydrogen, much of those dangling bonds will remain on the surface. Dangling bonds can easily absorb moisture and form Si-OH bonds, which will result in higher dielectric constant and leakage current. Hydrogen plasma provides hydrogen to passivate the surface and reduce the dangling bonds content and moisture uptake.
In conclusion, we have found that HSQ film is insensitive to light illumination; thereby, photo-induced leakage current of HSQ film is negligent under photo radiation. This indicates that HSQ has potential possibilities for being applied to the application in TFT display panel as the passivation layer.

Abstract (Chinese)......................................................i
Abstract(English)....................................................iii
Acknowledge................................................... v
Contents......................................................vi
Table Captions....................................................viii
Figure Captions..................................................... ix
Chapter 1 Introduction
1-1 General Background.....................................................1
1-2 High Transmittance Low-k Materials for TFT-LCD Panel Application....................................................2
1-3 Thesis Organization........................................4
Chapter 2 Characteristics of Low Dielectric Constant Hydrogen Silsesquioxane (HSQ)
2-1 Introduction...............................................6
2-2 Experimental Procedures....................................7
2-3 Results and Discussion.....................................8
2-4 Summary....................................................9
Chapter 3 Effects of Plasma Treatments on Leakage characteristics of Low k HSQ
3-1 Introduction..............................................11
3-2 Experiment Procedures.....................................12
3-3 Results and Discussion....................................13
3-4 Summary...................................................18
Chapter 4 Analysis of Leakage Current Conduction of Hydrogen Silsesquioxane with Various Treatments
4-1 Introduction..............................................19
4-2 Results and Discussion....................................20
4-3 Summary...................................................22
Chapter 5 Conclusion..........................................24
References....................................................26

[1] L. Peters, “Pursuing the perfect low-.kappa. dielectric,” Semiconductor International, Cover Story, p. 64, September 1998.
[2] K. Hinode, N. Owada, T. Nishida, K. Mukai, “,” J. Vac. Sci. Technol. B5, 518 (1987).
[3] S. A. Lytle, A. S. Oates, “The effect of stress-induced voiding on electromigration,” J. Appl. Phys., 71, 174 (1992).
[4] S. Venkatesan, et al., “A High Performance 1.8V, 0.20um CMOS Technology with Copper Metallization,” Tech. Dig. IEEE Int. Electron Devices, 1997, p. 769.
[5] D. Edelstein, et al., “Full Copper Wiring in a Sub-0.25 micro-m CMOS ULSI Technology,” Tech. Dig. IEEE Int. Electron Devices, 1997, p. 773.
[6] J. M. F. G. van Laarhoven, H. J. W. van Houtum, L. de Bruin, Int. VLSI Multilevel Interconnection Conf. Proc., 1989, p. 129.
[7] R. I. Hedge, R. W. Fiordalice, E. O. Travis, and R. J. Tobin, “Thin film properties of low-pressure chemical vapor deposition TiN barrier for ultra-large-scale integration applications,” J. Vac. Sci. Technol. B 11, 1287 (1993).
[8] P. Singer, “Looking Down the Road to Quarter-Micron Production,” Semiconductor International, Jan., 1995, p. 46.
[9] S. M. Rossnegal and D. Mikalsen, "Collimated Magnetron Sputter Deposition," J. Vac. Sci. Technol., A-9, 261 (1991).
[10] T. E. Seidel and C. H. Ting, “Methods and Needs For Low k Material Research,” Mater. Res. Soc. Symp. Proc. 381, 3 (1995).
[11] R. Y. Leung, T. Nakano, S. Case, B. Sung, J. J. Yang, and D. K. Choi, Int. Dielectrics for ULSI Multilevel Interconnection Conference, p. 49 (1997).
[12] G. Sugahara, N. Aoi, M. Kubo, K. Arai, and K. Sawada, “Low Dielectric Constant Carbon Containing SiO2 Films Deposited by PECVD Technique Using a Novel CVD Precursor,” Int. Dielectrics for ULSI Multilevel Interconnection Conference, p. 19 (1997).
[13] H. Treichel, G. Ruhl, P. Ansmann, R. Wuller, M. Dietlmeier and G. Maier, Proceedings of The First International Dielectrics for VLSI/ULSI Multilevel Interconnection Conference (DUMIC) (IEEE, Santa Clara, CA. 1998), p.201.
[14] V. McGayay, A. Acovic, B. Argarwala, G. Endicott, M. Shapiro, and S. Yankee, Int. VLSI Multilevel Interconnection Conf. Proc., p. 116 (1996).
[15] M. J. Loboda, C. M. Grove and R. F. Schneider, “Properties of a-SiOx:H Thin Films Deposited from Hydrogen Silsesquioxane Resins,” J. Electrochem. Soc., 145, 2861 (1998).
[16] H. Meynen, R. Uttecht, T. Gao, M. Van Hove, S. Vanhaelemeersch and K. Maex, in the Electrochem. Soc. Proceedings of the 3rd international Symposium on Low and High Dielectric Constant Materials, 98-3, 29 (1998).
[17] D. Thomas, and G. Smith, Dielectrics for ULSI Multilevel Interconnection Conf., p. 361 (1997).
[18] B. T. Ahlburn, G. A. Brown, T. R. Seha, and T. F. Zoes, Int. Dielectrics for ULSI Multilevel Interconnection Conference, p. 36 (1995).
[19] N. H. Hendricks, “Low Dielectric Constant Materials for IC Intermetal Dielectric Applications: A Status Report on the Leading Candidates,” Mater. Res. Soc. Symp.Proc., 443, 3 (1996).
[20] J. N. Bremmer, Y. Liu, K. G. Gruszynski, and F. C. Dall, Int. Dielectrics for ULSI Multilevel Interconnection Conference, p. 333 (1997).
[21] Jui-Chang Chuang, Mao-Chien Chen, “Effects of Thermal N2 Annealing on Passivation Capability of Sputtered Ta(-N) Layers Against Cu Oxidation,” J. Electrochem. Soc. 145, pp.4029, (1998).
[22] Jui-Chang Chuang, Mao-Chien Chen, “Passivation of Cu by Sputter-Deposited Ta and Reactively Sputter-Deposited Ta-Nitride Layers,” J. Electrochem. Soc. 145, pp.3137, (1998).
[23] J. G. Simmons, in L. I. Maissel and R. Glang (Eds.), Handbook of Thin Film Technology, Chap. 14, pp. 25, McGraw-Hill, New York, (1970).
[24] Lee,J.H. et al.,Asia Display '98, p.59(1998)
[25] Display roadmap summary, NEMI Tech. Roadmap., Dec.2000
[26] S. Sivoththamman, R. Jeyakumar, L. Ren, and A. Nathan, J. Vac. Sci. Technol. A 20(3), May/Jun 2002
[27] P. T. Liu, T. C. Chang, Y. L. Yang, Y. F. Cheng, and S. M. Sze, “Effects of NH3-plasma nitridation on the electrical characterizations of low-k hydrogen silsesquioxane with copper interconnects,” IEEE Trans. Electron Devices, 47, 1733-1739 (2000).
[28] S. M. Sze, Physics of Semiconductor Devices, Chap. 7, (Wiley, New York 1981) pp. 402-403.
[29] T. C. Chang, Y. J. Mei, “The novel improvement of low dilelectric costant hydrogen silsequioxane (HSQ) using hydrogen plasma treatment,” DUMIC proc., conf., p.337-p.340, 1997
[30] P. T. Liu, T. C. Chang, S. M. Sze, F. M. Pan, Y. J. Mei, W. F. Wu, M. S. Tsai, B. T. Dai, C. Y. Chang, F. Y. Shih and H. D. Huang, “Enhancing the thermal stability of low dilectric constant hydrogen silsequioxane (HSQ) by ion implantation,” Thin Soild Films 332, 345 (1998).