摘 要

本研究探討高氮量氮化鉭(TaN1+x)薄膜於矽基材之系統中，TaN1+x/Si界面微結構及反應，研究中採用Si(111) 5英吋晶圓為基板，以濺鍍方式沈積氮化鉭金屬薄膜30 nm，於真空壓力為5×10-5 torr的真空退火爐中，經退火處理500至1000℃持溫1小時，而後於爐中自然冷卻至室溫，以XRD、AES、TEM及HRTEM進行薄膜之相鑑定及結構分析。
TaN1+x薄膜於剛沈積時，為具非晶形結構之TaN相，經退火處理500℃持溫1小時之後，轉變成為具結晶結構之Ta3N5相，且隨著退火處理溫度上升至800℃持溫1小時之後，Ta3N5相會轉變成Ta4N5相。氮化鉭薄膜與矽基材界面之非結晶層(a-layer)為自然氧化矽，而此自然氧化矽層上之非晶層為形成矽化物前之中間過渡產物，而此厚度並不隨溫度上升而增加。因TaN1+x薄膜經退火溫度高達1000℃處理後，發現TaN1+x薄膜不與矽基材發生反應，故TaN1+x薄膜於積體電路製造程序中，為一鈍化膜是良好之擴散阻障層。
試片經退火處理1000℃持溫1小時後，於TaN1+x/Si之界面往矽基材處產生三角形結構析出物。此析出物經EDS成分分析後，為含碳之矽化物，此碳矽化合物應為試片於退火處理時遭受退火爐中之碳污染。最後為了初步了解在退火處理過程時，碳元素的來源及對試片的影響，所以加做了無鍍膜矽基材經氫氟酸清洗表面及未經氫氟酸清洗表面之二種試片的實驗。實驗過程以石墨做退火處理的基座，上面再放一個乾淨的矽晶片，而矽晶片上放上述之二種試片，然後和之前一樣的條件做退火處理1000℃持溫1小時。經AES及HRTEM分析後其三角形結構與TaN1+x薄膜試片發現的三角形結構應為相同之碳矽化合物。

Abstract

We studied the interfacial reaction when a thin film of tantalum nitride containing a high nitrogen concentration is deposited on a 5 inches silicon (111) wafer. The thickness of the tantalum nitride (TaN1+x) film was about 30 nm and obtained by a sputtering method.
After the tantalum nitride film was formed, annealing processes were carried out in a tube furnace with a vacuum level of 5 × 10-5 torr. The samples were annealed at temperatures ranging from 500-1000℃ for one hour in the vacuum furnace and cooled by furnace cooling. We studied the properties of the tantalum nitride film after the annealing processes through XRD, AES, HRTEM, and TEM analyses.
We found that the thin film of TaN1+x was amorphous in the as-deposited state, when annealing at a temperature of 500℃ for one hour the tantalum nitride turned into Ta3N5 crystals; however, annealing at a higher temperature of 800℃ for one hour turned Ta3N5 crystals into Ta4N5 crystals. In the cross-sectional TEM study, we observed there was an amorphous layer between the tantalum nitride and silicon substrate. However, the thickness of the amorphous layer remained the same in various annealing temperatures. The TaN1+x film did not react with the silicon substrate. Therefore, it is a good barrier film for IC processes.
In the annealing process at 1000℃, we observed a triangular silicide formation between TaN1+x and Si substrate. From the EDS analysis, we found the silicide contained a trace of carbon, which indicated the Si wafer was contaminated during the annealing process in the tube furnace.

參考文獻

1. H. D. Yosi and S. Lopatin, “ Integrated Electroless Metallization for ULSI ”, Electrochimica Acta, Vol. 44, pp. 3639-3949 (1999).
2. 莊達人，“VLSI製程技術”，高利出版社，民國86。
3. X. Sun, E. Kolawa, J. Chen, J. S. Reid, M. A. Nicolet, Thin Solid Films, 236,347 (1993).
4. Takeo Oku, “Diffusion barrier property of TaN between Si and Cu”, Applied Surface Science, 99, 265-272 (1996).
5. 邱垂福，“TaN/Ta/Si(100)之界面反應研究”，台灣科技大學，碩士論文 (2003)。
6. R. M. Walser and R. W. Bene, Appl. Phys. Lett. 28, 624 (1976).
7. F. M. d`Heurle, J. Mater. Res.1,205 (1986).
8. R. W. Bene, J. Appl. Phys.61 1826 (1987).
9. U. Gosele and K. N. Tu, J. Appl. Phys. 53, 3252 (1992).
10. T. B. Massalski,“Binary Alloy Phase Diagrams”ASM International (1990).
11. R. J. Contolini, L. Tarte, R. T. Graff, and L. B. Evans, “Copper Electroplating Process for Sub-Half-Micro ULSI Structure,” VMIC Conference, pp. 27-31 (1995).
12. B. Chin and P. Ding, “Barrier and Seed Layer for Damascene Copper Metallization,” Solid State Technology, Vol. 41, Issue 7, pp. 141-147 (1998).
13. C. H. Cho, S. S. Park, and Y. Ahn, “Three-Dimensional Wafer Scale Hydrodynamic Modeling for Chemical Mechanical Polishing,” Thin Solid Films, Vol. 389, pp. 254-260 (2001).
14. 陳珮儀，“無電鍍銅在Ta(N)阻隔層上成核與成長之研究”， 國立清華大學碩士論文 (2001)。
15. 蔡育成，“Ta2N/Si(100)之界面反應研究”，台灣科技大學，碩士論文 (2004)。
16. Y. S. Diamond, J. Elec. Mater, 30, 4 (2001).
17. J. M. Poate, K. N. Tu, and J. M. Mayer, Thin Films： Interdiffusion and Reactions, 376 (1978).
18. M. Stavrev, D. Fischer, F. Praessler, C. Wenzel and K. Drescher, J. Vac. Sci. Technol. A, 993 (1999).
19. Encyclopedia of Inorganic Chemistry, 5, 2498 (1994).
20. K. H. Min, K. C. Chun, K. B. Kim, J. Vac. Tech. B, 14(5), 3263 (1996).
21. 汪建民，”材料分析”，中國材料科學學會 (1998)。
22. 吳泰伯、許樹恩， “X光繞射原理與材料結構分析”，中國材料科學學會 (1996)。
23. 真空技術與應用”，行政院國家科學委員會精密儀器發展中心(2001)。
24. Omicron Ion Source Technical Manual, v2.3.
25. 潘扶民，電子月刊1卷2期96-103 (1995)。
26. D. Briggs, M. P. Seah, “Practical Surface Analysis by Auger and X-ray Photoelectron Spectroscopy ”,John Wiley ＆ Sons (1994).
27. Lawrence E. Davis etc., “Handbook of Auger Electron Spectroscopy” (1976).
28. D. Briggs, M. P. Seah, “Practical Surface Analysis Vol. 1”, Wiley (1990).
29. 潘扶民，國科會儀器總覽1-4 (1998)。
30. 潘扶民，科儀新知11卷2期8-22 (1989)。
31. 陳力俊等，”材料電子顯微鏡學”，國科會精儀中心 (1997)。
32. David B. Williams and C. Barry Carter, “Transmission Electron Microscopy” PLENUM (1996).
33. Wen-Horng Lee, Jing-Cheng Lin,Chiapyng Lee, “Material Chemistry and Physics” 68, 266-271 (2001).
34. H. Wang, Ashutosh Tiwari, A. Kvit, X. Zhang, and J. Narayan, “Applied Physics Letters” 80-13 (2002).
35. JCPDS File Card No.75-0627 (1997).
36. R. Hübner, M. Hecker, N. Mattern, V. Hoffmann, K. Wetzig, Ch. Wenger, H.-J. Engelmann, Ch. Wenzel, E. Zschech, J.W. Bartha, “Thin Solid Films” 437, 248-256 (2003).
37. C. S. Shin, D. Gall, Y. W. Kim, N. Hellgren, I. Petrov, and J. E. Greene, “Journal of Applied Physic” 92, 9, 5084-5093 (2002).