靜電式晶圓座(Electrostatic Chuck , E-chuck)隨著半導體製程的發展，已經成為將晶圓固定在真空腔體中的重要載具，有別於傳統的機械式晶圓固定座(Mechanical Chuck)有邊緣損失和晶圓表面變形的問題，或者是真空式晶圓固定座(Vacuum Chuck)在真空環境下無法利用壓力差達到有效的吸附，靜電式晶圓座可以讓晶圓平整的貼附在晶圓座表面，除了提供更穩定的吸附力以外也帶來更好的溫度控制。
為了在製程中判斷E-chuck是否有完整吸附，會利用平行板電容器原理，以晶圓和E-chuck所組成的兩個平行導板，因為彼此的距離變化而影響電容大小作為判斷，當晶圓被吸附時，與E-chuck的距離最短，得到的電容值最大；相反地，晶圓放置在E-chuck上，或者被釋放之後，因為支撐銷(lift pin)的高度提供額外的間距，讓距離變大所以電容最小，在這兩種間距內所形成的電容值變化，可經由訊號放大的邏輯電路計算，得知吸附(clamp)與釋放(unclamp)的晶圓感測值(wafer sense)，用量化方式判定E-chuck是否有成功將晶圓穩定吸附和完全釋放，假設出現了在吸附與釋放之間的晶圓感測值，則可以判定晶圓與E-chuck間距被殘留電荷或其他參數影響造成釋放不完全，則可以提前停機確認相關的運作機構，減少異常發生。
本研究以田口方法探討影響E-chuck晶圓感測值的各項因子，來穩定E-chuck 吸附以及釋放的晶圓感測值，並以吸附和釋放之間的晶圓感測值差異(wafer-sense gap)作為檢驗依據，當晶圓感測值差異越大就表示E-chuck順利完成吸附和釋放動作，透過田口實驗結果得知，E-chuck的支撐銷(lift pin)與支撐銷組件內部的支撐彈簧所提供的彈簧力為主要影響晶圓感測值的關鍵因子。隨著彈簧力和支撐銷高度的增加，晶圓感測值差異會越明顯；並且由實驗中得知，在支撐銷高度為0.45 mm的條件下，隨著彈簧力的增加，晶圓感測值差異會明顯加大，但是在相同的彈簧力下，隨著支撐銷高度的增高對晶圓感測值差異雖然有增加的效果，而增加的幅度沒有跟彈簧力一樣明顯，代表著彈簧力所帶來的增益比支撐銷高度還大，想要快速增加晶圓感測值差異的話，可以先把彈簧力增加到45 gw以上，再用支撐銷高度微調差異的範圍。以本實驗驗證最佳化的支撐銷長度與彈簧力組合而得出，當支撐銷的高度到達0.65 mm且搭配的彈簧力為48 gw時，就可以達到最大的晶圓感測值差異，不僅比原始參數的配置增加了一倍，並且在後續的30組E-chuck的測試結果中，符合95%信心水準的重複性以及穩定性，不但改善了E-chuck在吸附和釋放晶圓的一致性，也強化了機台於自動化過程中的辨識度依據。

Electrostatic chuck (E-chuck) has become an essential carrier for fixing wafers in vacuum process with the advanced semiconductor fabrication. E-chuck can provide more flat adhesion compared with mechanical chucks and vacuum chucks. So, the better temperature control is offered.
To determine the completeness of adhesion of the E-chuck during process, the parallel plate capacitor principle is utilized. Varied capacitance values formed by the wafer status on E-chuck surface are calculated. The distance between the wafer and the E-chuck becomes the shortest when the wafer is clamped, resulting in the highest capacitance and wafer sensing. Conversely, the lowest capacitance and wafer sense are obtained when the wafer is unclamped. The clamped and unclamped wafer senses are used to determine whether the E-chuck has successfully adhered to the wafer. If any wafer sense is detected between the clamped and unclamped states, the distance between the wafer and the E-chuck may be shortened by residual charge or other factors.
This study employs the Taguchi method to verify multiple factors affecting the wafer senses. The aim is to stabilize the clamp and unclamp wafer senses and prevent abnormalities in wafer loading and unloading. The difference between clamp and unclamp wafer sense is called wafer-sense gap. The larger the wafer-sense gap, the smoother the adhesion or release function of the E-chuck.
It is found that the spring force and the lift pin height are the primary factors influencing the wafer-sense gap through Taguchi experimental methods. The factor effect of spring force is more significant than that of the lift pin height. The spring force can make the wafer-sense gap more obvious when it rises to 45 gw. The wafer-sense gap can be quickly increased by first increasing the spring force to above 45 gw, then fine-tuning the range of the wafer-sense gap using the lift pin height. Based on this experiment, when the lift pin height reaches 0.65 mm with a spring force of 48 gw, the maximum wafer- sense gap can be achieved. This setup not only doubles the average wafer-sense gap compared to the original parameters but also meets the 95% confidence level. High reproducibility and stability are also shown in the following test results with 30 sets of E-chucks. This improvement enhances the consistency of the wafer adhesion and release function of the E-chuck and strengthens the basis for recognition in automated processes.

[1] G. A. Wardly, "Electrostatic Wafer Chuck for Electron Beam Microfabrication," Review of Scientific Instruments, vol. 44, no. 10, pp. 1506-1509, 1973.
[2] 賴建裕, "晶圓與靜電吸盤之熱傳分析," 國立台灣大學應用力學研究所, 2003.
[3] P. L. J. Reimund, K. Becker, D. St. Angelo "Electrostatic Clamp Performance," IEEE Ion Implantation Technology Proceedings, 1998 International Conference, vol. 1, pp. 280-283, 1998.
[4] Advanced Energy, "The Electrostatic Semiconductor Wafer Clamping/Chucking System(ESC).", https://www.advancedenergy.com/getmedia/0765eec8-b47d-427a-8a36-bfb8af5351f7/en-hv-amplifier-electrostatic-semiconductor-wafer-system.pdf.
[5] S. M. Huang, A. L. Stott, R. G. Green, and M. S. Beck, "Electronic transducers for industrial measurement of low value capacitances," Journal of Physics E: Scientific Instruments, vol. 21, no. 3, pp. 242-250, 1988.
[6] S. Kanno and T. Usui, "Generation mechanism of residual clamping force in a bipolar electrostatic chuck," Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, vol. 21, no. 6, pp. 2371-2377, 2003.
[7] K. Wang, Y. Lu, J. Cheng, and L. Ji, "Prediction of residual clamping force for Coulomb type and Johnsen–Rahbek type of bipolar electrostatic chucks," Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, vol. 233, no. 1, pp. 302-312, 2018.
[8] D. R. Wright, L. Chen, P. Federlin, and K. Forbes, "Manufacturing issues of electrostatic chucks," Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, vol. 13, no. 4, pp. 1910-1916, 1995.
[9] F. Kazutoshi Asano, IEEE, Fumikazu Hatakeyama, and Kyoko Yatsuzuka, Member, IEEE, "Fundamental Study of an Electrostatic Chuck for Silicon Wafer Handling," IEEE Industry Applications Conference, vol.38, no.3, pp.840 845, 2002.
[10] M. Kyoko Yatsuzuka, IEEE, Fumikazu Hatakeyama, Kazutoshi Asano, Senior Member, IEEE, and and S. Aonuma, "Fundamental Characteristics of Electrostatic Wafer Chuck with Insulating Sealant," IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 36, NO. 2, 2000.
[11] T. K. T. Watanabe, "Effect of Additives on the Electrostatic Force of Alumina Electrostatic Chucks," Journal of the Ceramic Society of Japan 100 [1] 1-6, 1992.
[12] T. K. a. C. N. Toshiya Watanabe, "Relationship between Electrical Resistivity and Electrostatic Force of Alumina Electrostatic Chuck," Japanese Journal of Applied Physics, Volume 32, Number 2R, 1993.
[13] M. Deguchi, "A simple method for detecting very small changes in capacitance or inductance," Microelectronics Journal, vol. 101, p. 104802, 2020.
[14] A. Ashrafi and H. Golnabi, "A high precision method for measuring very small capacitance changes," Review of Scientific Instruments, vol. 70, no. 8, pp. 3483-3487, 1999.
[15] W. Xingkuo et al., "Finite element analysis on factors influencing the clamping force in an electrostatic chuck," Journal of Semiconductors, vol. 35, p. 094011, 2014.
[16] "弗萊明左手定則Fleming’s left hand rule." https://www.bbc.co.uk/bitesize/guides/zc3dxfr/revision/3
[17] D. R. Wright, D. C. Hartman, U. C. Sridharan, M. Kent, T. Jasinski, and S. Kang, "Low temperature etch chuck: Modeling and experimental results of heat transfer and wafer temperature," Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 10, no. 4, pp. 1065-1070, 1992.
[18] 孫詩壯與趙晉榮, "庫倫型静電卡盤吸附力受電極結構及晶圓氧化層影響的研究," 真空科學與技術學報第43卷第8期, 2023.
[19] 張段芹, 褚金奎與劉建秀, "微加工工藝製作的静电吸片及其切向吸附力," 微纳電子技術第51卷第2期, 2014.
[20] G. Kalkowski, S. Risse, S. Müller, and G. Harnisch, "Electrostatic chuck for EUV masks," Microelectronic Engineering, vol. 83, no. 4-9, pp. 714-717, 2006.
[21] 陳韋閔, "電極電壓對靜電式晶圓座(ESC)晶圓釋放的影響研究," 國立中興大學電機工程學系, 2013.
[22] G. I. Shim and H. Sugai, "Dechuck Operation of Coulomb Type and Johnsen-Rahbek Type of Electrostatic Chuck Used in Plasma Processing," Plasma and Fusion Research, vol. 3, pp. 051-051, 2008.
[23] L. D. Hartsough, "Electrostatic wafer holding." Solid State Technology, vol. 36, no. 1, pp. 87-90, 1993.
[24] S. Q. a. A. McTeer, "Wafer dependence of Johnsen–Rahbek type electrostatic chuck for semiconductor process," JOURNAL OF APPLIED PHYSICS 102, 064901, 2007.
[25] Y. Sun, J. Cheng, Y. Lu, Y. Hou, and L. Ji, "Design space of electrostatic chuck in etching chamber," Journal of Semiconductors, vol. 36, no. 8, 2015.
[26] B. F. Peter Andrews, John Dunklee, "Chuck With Intergrated Wafer Support," U.S. Patent US 7,688,091 B2, 2010.
[27] T. W. Yoon, S. I. Cho, M. Choi, and S. J. Hong, "Heat transfer mechanism of electrostatic chuck surface and wafer backside to improve wafer temperature uniformity," Journal of Vacuum Science & Technology B, vol. 41, no. 4, 2023.
[28] 李輝煌, 田口方法-品質設計的原理與實務. 高立圖書有限公司, 2004.
[29] 菅原利文, 天滿康之, 林基樹與辰己良昭, "靜電吸盤裝置及其控制方法," 中華民國專利 201403742, 2013.
[30] K. J. Jeong, S. Spoutai, S. H. Choi, T. Y. Cho, and H. G. Chun, "A study on the fabrication and characterization of alumina electrostatic chuck for silicon wafer processing," in Proceedings Third Russian-Korean International Symposium on Science and Technology. KORUS'99 (Cat. No.99EX362), vol. 2, pp. 532-535 vol.2, 1999.