臺灣博碩士論文加值系統

摘要
隨著半導體技術的進步，元件的尺寸不斷的縮小，而入深次微米的領域中。為了增加積體電路的性能，降低導線的線寬和增加金屬導線層的數目，便成為超大型積體電路技術所需採用的方式。然而電子訊號在金屬導線間傳遞所造成的延遲，變成半導體元件速度受限的主要原因。為了降低訊號傳遞的時間延遲，使用低介電常數材料作為導線間的絕緣層，便可降低導線間的電容值，使元件在速度方面的性能提高，並且可以降低功率的消耗(power dissipation)及雜訊干擾(cross-talk noise)。整合Cu與low-k可以增進元件切換速度，這也是目前半導體研究領域的一個既定的趨勢。目前Cu已引入0.1８μm製程，但low-k尚未引入，因low-k諸多問題未解決，例如：如何蝕刻與光阻的去除。
低介電常數材料（low-k）目前發展包括：有機類(organic)與無機類(non-organic)、二大類材料，但這兩大類low-k應用於IC製程上卻產生一些新問題，其中一個非常嚴重的問題就是去光阻的灰化過程（ashing process），因為灰化過程中使用的氧電漿會對low-k薄膜造成很大損害，使得low-k薄膜的特性變差，介電常數上升，漏電流增加、薄膜失去好的絕緣性，這會使得IC製程的良率下降甚多。
X-ray微影的方法正是解決這個問題的關鍵技術，低介電材料經過X-ray曝光後，部分薄膜已經固化，再將未固化的部分用溶劑溶解，則圖形就能產生。此外，在深次微米的元件製作過程中，波長越短解析度越高；原本採用深紫外光，但在0.13μm以下，深紫外光的解析度已不足，需再找更小波長當曝光光源，而X-ray正是符合短波長的光源之一。

Abstract
As integrated circuit dimensions continue to shrink, interconnect RC delay becomes an increasingly serious problem. Fabrication of interconnect structures using new materials of low resistivity and low permittivity to replace the traditional Al and SiO2 interconnect technology is in high demand. Specially, copper and low dielectric constant (low-k) polymers show great promise. Among various low-k materials, spin-on glass (SOG) materials have been widely used as an interlayer dielectric in multilevel interconnections because they are applied easily and have relatively low process costs. One class of materials, which offers many of properties of silica (SiO2) hardness, thermal and dimensional stability etc.) are the HOSP (Hybrid Organic-Siloxane-Polymer)and HSQ (Hydrogen Silsesquioxane) represent an important member of this family. HOSP and HSQ exhibits a relatively low dielectric constant (k=2.6-2.8) as compared to SiO2 (k=4.0).It is intrinsically hydrophobic, has reasonable mechanical hardness, and possesses exceptional thermal and dimensional stability (in excess of 400℃). For these reasons, HOSP and HSQ represent an excellent candidate for applications on the multilevel interconnect architecture. On the other hand, etching and PR removal are key technology during the manufactures of multilevel interconnects. X-ray lithography process is adopted to avoid these issues. As a result, a novel X-ray lithography technology for the low-k interlayer has been proposed for fabrication of IC. And it is a low cost process.
In this work, the characteristics of PR removal have been investigated. Experimental results have shown that the dielectric properties of HOSP and HSQ are degraded by PR removal process. The X-ray exposure will solve these problems and it will be a useful tool in advance ICs fabrication. The advantage of the X-ray exposure is the direct patterning, avoids the issues during the etching and photoresist striping processes. The part of film exposed by X-ray will be cured and the other part could be dissolved with the solvent. Strictly speaking, these two issues will be overcome by the X-ray curing.

Contents

Chapter 1 Introduction
1.1. General Background .......................................... 1
1.2. Motivation and Material Options .........................,,,, 3
1.3. Organization of This Thesis ................................. 8

Chapter 2 The synchrotron radiation X-ray lithography beam line constructed at SRRC
2.1. Introduction ............................................ 9
2.2. The optical system of the X-ray lithography beamline...............11
2.3. The exposure system .....................................14
2.4. Summary .................................................17

Chapter 3 Intrinsic Properties of HOSP and HSQ
3-1. Introduction ........................................... 18
3-2. Experimental............................................ 19
3.3. Results and Discussions .................................... 20
3.4. Summary..................................................... 25

Chapter 4 Effects of X-ray exposure on HSQ and HOSP
4-1. Introduction.............................................27
4-2. Experiment ............................................. 28
4-3. Results and Discussion ................................. 29
4.3-1. effects of X-ray exposure on HOSP......................... 29
4.3-2. effects of X-ray exposure on HOSP .........................30
4.3-3. furnace annealing after X-ray curing on HOSP ..31
4.3-4. furnace annealing after X-ray curing on HSQ ...32
4.3-5. SEM image......................................32
4.4. Summary..................................................... 33

Chapter 5 Conclusions and Suggestions for Future Work
5-1. Conclusion ............................................. 35
5-2. Suggestions for Future Work .............................36
References....................................................... 38

References
[1]L. Peters, Semiconductor International, Sep. p.64, 1998
[2]S.-Y. Oh. et al., SRC Topic Research Conference Workshop on Low Dielectric Interlayer Dielectrics for High Performance Circuits, RPI, Troy, NY, Aug. 9-10, 1994
[3]T. S. Kuan, Dielectrics and CVD Metallization Symp., San Diego, CA, Feb. 7-8, 1994
[4]T. E. Seidel, C. H. Ting, Material Research Society Symp. Proc. vol. 381, p.3, 1995
[5]C. B. Case, C. J. Case, A. Kornblit, M. E. Mills, D. Castillo, R. Liu, Materials Research Society, vol. 443, p. 177
[6]Neil H. Hendricks, Materials Research Society, vol. 443, p.3, 1997
[7]B. Roberts, A. Harrus, and R. L. Jackson, Solid State Technology, Feb. p.69, 1995
[8]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), p.201, (IEEE, Santa Clara, CA. 1998)
[9]T. Homma and Y. Murao, Proc. VLSI Multilevel Interconnection Conf., p.71, 1993
[10]T. Homma, Y. Murao, and R. Yamagushi, J. Electrochem. Soc., p.140, 1993
[11]J. Ida, M. Yoshimaru, T. Usami, A. Ohtomo, K. Shimokawa, A. Kita, and M. Ino, Proc. IEEE Symp. on VLSI Technology, IEEE, New York, p.59, 1994
[12]T. Fukada and T. Alca Hori, Proc. Dielectrics for VLSI/ULSI Multilevel Interconnection Conf., p.43, 1995
[13]L. Q. Quian, H. W. Fry, G. Nobinger, J. T. Pye, M. C. Schmidt, J. Cassials, and M. Lieberman, Proc. Dielectrics for VLSI/ULSI Multilevel Interconnection Conf., p.50, 1995
[14]T. Hifumi, H. Sumitani, K, Itoga, H. Watanabe, M. Inoue, K. Marumoto, H. Ohsawa, and K. Saitoh, Japan J. Appl. Phys. 1, Vol36, No.6A, p.3463, 1997.
[15]K. Deguchi, K. Miyochu, M. Oda, T. Matsuda, A. Ozawa, and H. Yoshihara,J. Vac. Sci. Technol. B, Vol.14, No.6, p.4294, 1996.
[16]Y. Maejima and N. Awaji, Japan J. Appl. Phys. Vol. 32, Part 1, Np. 12A, p. 5801, 1993.
[17]R. P. Haelbich, J. P. Silverman, W. D. Grobman, J. R. Maldonado, and J. N. Warlaumont, J. Vac. Sci. Technol. B, Vol.1, No.4, p.1262, 1983.
[18]K. Okada, K. Fujii, Y. Kawase, and M. nagano, J. Vac. Sci. Technol. B, Vol.6, No.1, p.191, 1983.
[19]F. Z. Hsiao, G. Y. Hsiung, and J. R. Chen, J. the. Vac Sci. of R.O.C, 1998