細小銅球可應用於半導體元件或燒結型熱管上，能大幅提升反應速率及最大熱傳量。本研究利用均勻液滴噴射概念，設計實驗流程與製作實驗設備，即是製作一組高溫之坩堝搭配溫控模組、真空化設備、高速影像擷取系統、壓電式震盪器等設備，並建立系統化製程技術，以製作均勻單一粒徑之細小銅球。實驗中建立液滴成形之絕氧環境及真空化機制，將銅金屬熔融成液體狀，並使用壓電式震盪器使之產生均勻振波，讓銅液經震盪之作用後，使其經過噴嘴之後斷裂為均勻之液滴，並依靠表面張力形成粒徑均勻之銅球。於研究中，首先要克服的是高溫對實驗設備與方法之嚴苛考驗；再者，針對於三種不同孔徑噴嘴，作均勻液滴噴射法之實驗分析，尋找產生均勻粒徑之細小銅球的震盪頻率、進氣壓力等操作參數。同時對所製作之銅球成品進行外觀與結構組織觀察及EDS成份分析，以確定所建立製程之可行性與實用性。本研究所獲得之結果可作為細小銅球後續研究之重要參考。

Tiny copper balls can be applied to semiconductor components and sintered-type heat pipes, which can promote the response rate of the semiconductor device and the maximum heat transfer rate of the heat pipe. In this study, the uniform-droplet spray concept is used to design the experiment procedures and the experimental equipment. The latter one includes a high temperature crucible combined with thermal control system, vacuum apparatus, high speed image captured system and piezoelectric vibrator. With the designed equipment, a systematically fabricated process for making tiny copper balls with a uniform diameter is constructed. In the experiment, the vacuum mechanism and the oxygen-isolated environment for forming uniform droplet are established. Copper is melted in the crucible and then the piezoelectric vibrator is used to make uniform wave to break the flow of copper liquid when passing through the spray nozzle. Due to surface tension, cooper balls of single diameter are formed after cooling. In this work, firstly, the severe challenges of high temperature to the experimental equipment and procedures are overcome. Secondly, the working parameters, such as the frequency of piezoelectric vibrator, inlet nitrogen pressure of the crucible, etc., are explored to make uniform droplets for there different sizes of outlet nozzles. The resulting tiny copper balls are examined by observing the exterior appearances and the microstructures and by analyzing the elemental composition with EDS. The results from this work would be an important reference for the future study on making tiny copper balls.

[1] 林舜天, “銅粉之製造方法” ,熱導用銅粉之選擇、製造、燒結與測
試研討會, 中華民國粉末冶金協會出版, 台北, 2005.

[2] Sevart F. “ Memoiresurla constitution des veins liquids lances pardes orifices circulaires en mince paroe, ”4nn. Chin, 1833, 53: 337

[3] Magnus G. “On the swellings formed in jets issuing from circular orifices. ” Phil Mag, 18: 161

[4] Fillmore G L, Buehner W L, West D L. “Drop charging and deflection in an electrostatic ink jet printer. ” IBM J Res Develop, 1977. 1

[5] Orme M. “A novel technique of rapid solidification net-form materials synthesis.” J Mater Eng Perf, 1993, 2(3): 399

[6] J.H. Chun and C.H. Passow, “A Study of Spray Forming Using Uniform Droplet Spray,” U.S. Patent, No.5, 266, 098, 1993.

[7] B.V. Artem’ev and S.G. Kochetov, “Capillary Breakup of a Liquid Metal Jet in an Oxidizing Medium,” Journal of Physics, Vol. 60, pp. 425-429, 1991.

[8] H. Haj-Harir and D. Poulikakos, “Capillary Instability of a Cylindrical Jet with an shroud: A Model for the Breakup of an Oxidized Metal Jet,” Journal of Applied Mechanic, vol.67, pp. 626-628, 2000.

[9] P.Yim, J.H Chun, T. Ando and V. K. Sikka, “Production and Charaterization of Mono-sized Sn-38wt%Pb Alloy Balls,” The International Journal of Power Metallurgy, vol. 32, No.2, pp.155-163, 1996.

[10] 賴維祥、陳家進,“氧化對熔融金屬液柱斷裂及其成之顆粒外形之影響”，粉末冶金會刊，第 28 卷，第 2 期，pp. 76-87, 2003.

[11] Yao Yingxue, Gao Shengdong, Cui Chengsong, “Rapid prototyping based on uniform droplet spraying,” Journal of Materials Processing Technology 146 (2004) 389–395

[12] J.-P. Cherng, J.-H. Chun and T. D. Ando: Proc. TMS Annual Meeting – Solidificatinn 1998, pp. 317.

[13] 林岳儒、黃坤祥，「粉末特性對燒結式熱導管散熱性能的影響」，
工業材料，vol. 231，pp. 88-94, 2006

[14] 卓暐傑、曾憲中, “具多流向堆疊銅球之強制對流熱傳分析” 建國科技大學 機電光系統研究所碩士論文, 2005

[15] 李石成，“BGA錫球之製程研究”，國立成功大學工程科學所碩士論文, 2005.

[16] 邱啟勝，“BGA錫球製程研究及影像控制”，國立成功大學工程科學所碩士論文, 2006.

[17] 于洋、史耀武、夏志東、雷永平，“均勻液滴噴射成球法的射流速度計算” 電子元件與材料 第26卷，第10 期，pp. 57-61, Oct. 2007

[18] 高勝東、姚英學、崔成松，“金屬均勻液滴束流技術的應用” 材料導報 第20卷，第1 期，pp. 95-98, Janu. 2006

[19] Sakai T，Koshino N . “Production of Uniform Droplets by Longitudinal Vibration of Audio Frequency”[J]. J Chem Eng Japan, 1980, 13:267

[20] Paul A, Hass. “Formation of Uniform Liquid Drops by Application of Viration Laminar Jet” [J] . Ind Eng Chem Res., 1992, 31 :959~967