摘 要

本文針對管壁加熱之彎管流道內部的肅氣乾燥過程進行理論分析與數值模擬。彎管流道普遍存在於半導體製程設備上所廣泛使用之氣體控制模組中。由於半導體製程對於製程氣體之純度(特別是溼度)要求極為嚴苛，當設備因定期或突發狀況維修，並曝露於含有過多水汽之環境後，再重新啟動暖機時必須先利用超高純度之製程氣體來排除殘留於流道中及吸附於流道內壁之水汽。而其中重要課題之一即為如何改善系統設計以降低肅氣乾燥過程所需時間，進而提高設備平均產能。

本文中結合流體力學、熱質傳學、以及水汽在金屬表面吸附/解離之表面科學知識，建立了一套完整之理論模型，並在其基礎上以數值模擬的方式探討流道內氣體流量與管壁加熱量等因素對肅氣乾燥時間的影響。數值實驗結果指出，當氣體流量固定時，管壁加熱量越大則管壁平均溫度越高，進而縮短肅氣乾燥時間。同時，在固定管壁加熱量的情況下，加大氣體流量也可以縮短乾燥過程時間。然而，因加大氣體流量有降低管壁平均溫度之效果，在高流量下管壁加熱縮短乾燥時間之程度不如低流量時之減少程度。這些研究結論可以做為氣體控制模組肅氣乾燥過程中流量與加熱量之最佳管制的參考依據。

ABSTRACT

In this thesis we study the moisture purge/dry-down process in a heated curved pipe. Curved pipes constitute a substantial part in gas control modules that are widely used in the semiconductor industry. The purge/dry-down process is essential since semiconductor fabrication processes strictly demand high purity (in particular, low humidity) of the process gases. Also, one of the central issues here is to shorten the purge/dry-down time required to reduce the moisture content of the process gas to a satisfactory level, so as to reduce the equipment warm-up time after regular or accidental maintenance, thereby increasing the average productivity of the equipment.

Here we successfully combine theories of fluid mechanics, heat and mass transfer, and moisture adsorption/desorption dynamics on metals, to develop a complete model for the moisture purge/dry-down process. On the basis of the theoretical model, we carry out systematic numerical simulations of the purge/dry-down process. For a particularly chosen pipe geometry, the effects of wall heat flux and flow rate on the purge/dry-down time are investigated. The numerical results indicate that increasing the wall heat flux would shorten the purge/dry-down time, as it raises the average wall temperature. Meanwhile, for a particular wall heat flux, increasing the flow rate would shorten the time required for the moisture content of the exit gas to reduce to a preset low level. However, since increasing the gas flow rate also has the side effect of cooling down the pipe wall, the time required to completely purge the moisture preexistent in the pipe would actually become longer. These findings are expected to be useful for purge/dry-down process optimization.

參考文獻

[1] 魏依玲，我國半導體設備產業發展之契機，工研院ITIS產業評析，中華民國87年11月。

[2] 八十九年度機械業關鍵零組件計畫業界合作公開說明會簡報，工業技術研究院機械工業研究所，中華民國88年6月24日。

[3] 莊達人，VLSI製程設備，高立圖書有限公司，中華民國87年10月。

[4] D. Sheriff, Manifold destiny : Gas systems go modular, Solid State Technology 40 (10), October 1997﹒

[5] J. Eustice, Experiments of Streamline Motion in Curved Pipes, Proc. R. Soc. London Ser. A85, pp. 119-131, 1911﹒

[6] W. R. Dean, Note on the Motion of Fluid in a curved Pipe, Philos. Mag., pp. 208-223, 1927﹒

[7] S. A. Berger and L. Talbot, Flow in curved pipes, Ann. Rev. Fluid Mech. 15, pp. 416-512, 1983﹒

[8] W. Y. Soh and S. A. Berger, Laminar entrance flow in a curved pipe, J. Fluid Mech., Vol. 148, pp. 109-135, 1984﹒

[9] S. V. Patankar, V. S. Pratap and D. B. Spalding, Prediction of laminar flow and heat transfer in helically coiled pipes, J. Fluid Mech., Vol. 62, Part 3, pp. 539-551, 1974﹒

[10] A. M. Haider and F. Shadman, Desorption of moisture from stainless steel tubes and alumina filters in high purity gas distribution systems, IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 14, No. 3, pp. 507-511, 1991﹒

[11] K. Siefering and H. Berger, Improved APIMS methods, J. Electrochem. Soc., Vol. 139, No. 5, pp. 1442-1445, 1992﹒

[12] C. Ma, A. M. Haider and F. Shadman, Atmospheric pressure ionization mass spectroscopy for the study of permeation in polymeric tubing, IEEE Transactions on Semiconductor Manufacturing, Vol. 6, No. 4, 1993﹒

[13] P. E. Noel, M. Chigirinskiy, A. Athalye, K. Siefering and W. Whitlock, Optimization of cost versus performance of gas distribution systems through contamination modeling, IEEE/SEMI Advanced Semiconductor Manufacturing Conference, pp. 232-236, 1993﹒

[14] K. Siefering, W. Whitlock, and A. Athalye, BOC Electronic Gases, Modeling moisture adsorption and transport in ultra-high-purity gas piping systems, Microcontamination, Vol. 12, No. 3, 6p, March 1994﹒

[15] C. Ma and N. Verma, Moisture drydown in ultra-high-purity oxygen systems, Journal of the IEST, Vol. 41, No. 1, pp. 13-15, 1998﹒
[16] S. Dheandhanoo, J. H. Yang, R. J. Ciotti, and D. F. Yesenofski, Empirical validation of a gas distribution system moisture drydown model, Journal of the IEST, Vol. 41, No. 2, pp. 33-38, 1998﹒

[17] S. V. Patankar and D. B. Spalding, A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows, Int. J. Heat Mass Transfer, Vol. 15, pp. 1787-1806, 1972﹒

[18] D. M. Ruthven, Principles of Adsorption and Adsorption Processes, Wiley, New York, 1984﹒

[19] J. Benard, Ed., Adesorption on Metal Surfaces, Elsevier, Amsterdam, 1983﹒

[20] 楊天祥，氣體控制模組流道之肅氣乾燥模擬(工業技術研究院分包學術機構研究期末報告)，國立成功大學機械科技研發中心，中華民國89年8月25日。

[21] S. V. Patankar and D. B. Spalding, Heat and Mass Transfer in Boundary Layers, 2nd edition, Intertext Books, London, 1970﹒

[22] F. P. Incropera and D. P. DeWitt, Fundamentals of Heat and Mass Transfer, 4th ed., Wiley, New York, 1996﹒

[23] B. R. Munson, D. F. Young, and T. H. Okiishi, Fundamentals of Fluid Mechanics, 3rd ed., Wiley, New York, 1998﹒

[24] 吳俊賢，”彎管流道肅氣乾燥過程之數值研究”，國立成功大學機械工程研究所碩士論文，2001﹒

[25] S.V. Patankar, Numerical Heat Transfer and Fluid Flow, Hemisphere, Washington, 1980﹒

[26] 楊天祥，吳俊賢，彎管流道肅氣乾燥過程之數值研究(第八屆全國計算流體力學學術研討會)，國立成功大學機械工程學系，中華民國90年8月。

[27] John B. Hudson, Surface Science An Introduction , Fjohn Wiley & Sons, Inc, 1992﹒

[28] Brunauer, S,Emmett, PH, and Teller, E. J. Am. Chem. Soc. 1938；60：309﹒