MEMS的面型微細加工，使得半導體製程製作之二維積層薄膜結構，得以產生三維度的懸浮微結構，利用元件結構層與犧牲層材料之間的選擇性蝕刻，將犧牲層去除而留下結構層，此過程則稱之為結構釋放。對於最廣為採用的濕式結構釋放過程，其後通常必須再經歷清洗與乾燥兩個步驟，微結構才可真正懸浮於基底之上，但是過程中卻非常容易發生結構與基底之間的黏著貼底(stiction)現象。此現象通常發生於矽晶材料所形成之立體懸浮或中空結構內，形成原因主要是受到薄膜殘留應力與界面材質的影響。目前此現象的發生已成為壓力感測器面型微細加工技術發展的最大障礙。
本實驗是要探討採用面型微加工技術來製作多晶矽感壓薄膜，其在結構釋放後所遭遇的薄膜形變問題、並提出解決方法。晶片的製作係利用國家奈米元件實驗室(NDL)及國科會南區微機電系統中心的設備進行，利用面型微細加工和犧牲層溼蝕刻技術在晶格方向(100)的p型矽晶圓上一體成型製作出多晶矽感壓薄膜，並利用高溫爐管實施1100℃的退火，以大幅降低薄膜的殘留應力，之後分別利用通入異丙醇與二氧化碳超臨界法來降低水的表面張力的影響。由實驗結果得知，吾人已成功地達到避免薄膜黏著貼底的現象，並獲得十分良好的研究成果。

Surface micromachining is a process to fabricate free standing and freely moving microstructures in a large two dimensional design space. The tick is to deposit and pattern two thin films of materials that can be etched away selectively with respect to each other. After the etch process, the sacrificial layer is removed by etching solvent. When wet etching step is finished and wafer have to be cleaned by DI water, during the drying and evaporation process, the microstructure can be easily ravaged by water capillary force and result in the deformation of structural layer . Stiction phenomenal usually occurs in the hollow construction formed by polysilicon, and its major happening reason is thin film residual stress and different interface material .This phenomenal is becoming the major obstruction in the development of micro-pressure sensors of surface micromachining.
This thesis is discussing thin film diaphragm deformation problems during the fabricating process that when using surface micromachining method to fabricate micro-pressure sensors and proffers some solving methods. The sensing chips are made by fabrication equipment in NDL and STNRC. In order to solve thin film stick problems, we not only apply methods of decreasing water capillary force by irrigating isopropyl alcohol、supercritical drying of CO2 , but also reduce residual stress under the annealing process in the high temperature furnace at 1100℃ .We have already accomplish our expectation successfully and won excellent research result .

1. Alley, R. L., Cuan, G. J., Howe, R.T. and Komvopoulos, K., "The effectect of release-etch processing on surface microstructure stiction," Proc. IEEE Solid-state Sensor and Actuator workshop, Hilton Head Island, SC, 21-25 June 1992. pp.202-207.

2. Core, T. A., Tsang, W.K. and Sherman, S. J., "Fabrication Technology for an Integrated Surface-Micromachined Sensor," Solid State Technology, October, pp.39-47, 1993

3. Elliott, D. J., "Integrated Circuit Fabrication Technology," 2nd ED., McGraw Hill, 1989.

4. E. Kalvesten, “The First Surface Micromachined Pressure Sensor for Cardiovascular Pressure Measurements,” IEEE, MEMS-98, pp. 574-579, 1998

5. Gould, G. and Irene, E. A., "An in situ Study of Aqueous HF Treatment of Silicon by Contact Angle Measurement and Ellipsometry," Journal of Electrochemical Society : Solid-State Science and Technology, Vol. 135, No. 6, pp.1535-1539, 1988

6. Guckel, H. and Burns, D. W., "Planar Processed Polysilicon Sealed Cavities for Pressure Transducer Arrays," IEDM 84, pp.223-225, 1984

7. Guckel, H., Burns, D. W., Nesler, C. K., and Rutigliano, C. R., "Fine Grained Polysilicon And its Apllication to Planar Pressure Transducers," 4th International Conference on Solid-state Sensor and Actuators(Transducers ’87), Tokyo, Japan, 1993, p.277-282

8. Guckel, H., Christenson, T. R., Skrobis, K. J., Sniegowski, J. J., Kang, J. w., Choi, B., Lovell, E. G. "Microstruture Sensors," Electron Devices Meeting, 1990. Technical Digest., International , 1990 , pp. 613 -616

9. Guckel, H., Sniegowski, J. J. and Christenson, T. R., "Advance in processing teching for silicon micromechanical stiction devices with smooth surfaces," Proc. IEEE Micro Electro Mechanical System, Salt Lake City, UT ,20-22 February, 1989, pp.117-122

10. Guckel, H., Sniegowski, J. J. and Christenson, T. R., "Fabrication of Micromechanical Devices from Polysilicon Films with Smooth Surfaces," Sensors and Actuators, 20, pp.117-122, 1989

11. Houston, M. R., R. Maboudian, and R. Howe " Ammonium Fluoride Anti- Stiction Treatment for Polysilicon Microstructures ,"8th International Conference on Solid-state Sensor and Actuators(Transducers ’95), Stockholm, Sweden, 1995, p.210-213

12. Israelachvili, J. N., "Intermolecular and Surface Forces," Academic Press, London, 1992

13. Jerman, J. H., "The Fabrication and Use of Micromachined Corrugated Silicon Diaphragms," Sensor and Actuators, vol. 32, no. 3, Apr. 1990,pp.998-992

14. Judge, J. S., "A Study of the Dissolution of SiO2 in Acidic Flouride Solutions," Journal of the Electrochemical Society : Solid State Science, Vol. 118, No. 11, pp.1772-1775, 1971

15. Jie Yang, Harold Kahn, An-Qiang He, Stephen M. Phillips, Senior Member, IEEE, and Arthur H. Heuer, "A New Technique for Producing Large-Area As-Deposited Zero- Stress LPCVD Polysilicon Films：The MultiPoly Process, " IEEE Journal of microelectromechanical systems,Vol. 9, No. 4, December 2000

16. Kim, C. J., Kim, J. Y., Sridharan, B., "Comparative Evaluation of Drying Techniques for Surface Micromachining," Sensor and Actuator A: physical/ Volume: 64, Issue: 1, 1998, pp.17-26

17. Komvopoulos, K. " Surface engineering and microtribology for microelectromechanical systems," Wear Volume: 200, Issue: 1-2 , December, 1996, pp.305-327

18. Lee, Y. I., Park, K. H., Lee, J., Lee, C. S., Yoo, H.J., Kim, C. j., and Yoon, H. J. " Dry Release for Surface Micromachining with HF Vapor-Phase Etching," Journal of Microelectromechanical Systems, VOL. 6, NO. 3, SEPTEMBER 1997, pp.226-233

19. Legtenberg, R., Elders, J., and Elwenspoek, M., "Stiction of Surface Microstructure after Rinsing and Drying: Model and Investigation of Adhesion mechanisms," Processing of Transducers '93, the 7th International Conference on Solid-state Sensor and Actuators , Yokohama, Japan, June 7-10, 1993, Institute of Electrical Engineers, Japan, pp.198-201

20. Lin, L., Yun, W., Chu, H. C. and Chiao, M., "Surface Micromachined Diaphragm Pressure Sensors with Optimized Piezoresistive Sensing Resistors," International Conference on Microelectronics and VLSI, TENCON '95, IEEE, pp.24-27, 1995

21. Miller, S. L., Rodgers, M. S., LaVigne, G., Sniegowski, J. J., Clews, P., Tanner, D.M., and Peterson, K.A., "Failure Modes in Surface Micromachined MicroElectroMechanical Actuators," IEEE Trans., pp.17-25, 1998

22. Mishima, H., Yasui, T., Mizuniwa, T., Abe, M., and Ohmi, T., IEEE Trans. Semicond. Manuf.,2, (1989), pp.69-75

23. Monk, D. J., Soane, D. S. and Howe, R. T., "A Review of the Chemical Reaction Mechanism and Kinetics for Hydroflouric Acid Etching of Silicon Dioxide for Surface Micromachining Applications," Thin Solid Films, 232, pp.1-12, 1993

24. Mulhern, G. T., Soane, D. S. and Howe, R. T., "Supercritical Carbon Dioxide Drying of Microstructures ," Processing of Transducers '93, the 7th International Conference on Solid-state Sensor and Actuators , Yokohama, Japan, June 7-10, 1993, Institute of Electrical Engineers, Japan, pp296-299

25. Mastrangelo, C. H., Saloka, G. S., "A dry-release method based on polymer columns for microstructure fabrication" MEMS '93, Proceedings 'An Investigation of Micro Structures, Sensors, Actuators, Machines and Systems'. IEEE, pp.77-81, 1993.

26. Pfann, W. G. and Thurston, R. N., "Semiconducting Stress Transducers Utilizing the Transverse and Shear Piezoresistance Effects," Journal of Applied Physics, Vol. 32, No. 10, pp.2008-2019, 1961
27. Pong K., Ho C., Liu J. Tai Y., “Non-linear pressure distribution in uniform microchannels, “ in Appl. Microfabrication to Fluid Mechanics, ASME Winter Annu. Meet., pp.51-56, Chicago, IL Nov. 1994.

28. Sharpe, W. N., Yuan, B. Jr. and Vaidyanathan, R., "Measurements of Young’s Modulus, Poisson’s Ratio, and Tensile Strength of Polysilicon," Tenth Annual International Workshop on Micro Electro Mechanical Systems, MEMS '97, Proceedings, IEEE, pp.424-429, 1997

29. Smith, C. S., "Piezoresistance Effect in Germanium and Silicon," Physical Review, Vol. 94, No. 1, pp.42-49, 1954

30. Sugiyama, S., Shimaoka, K. and Tabata, O., "Surface Micromachined Micro-Diaphragm Pressure Sensors," International Conference on Solid-State Sensors and Actuators, Transducers '91 Digest of Technical Papers, pp.188-191, 1991

31. Sze, S. M., "Semiconductor Sensors," John Wiley & Sons, Inc., New York, 1994

32. Takeshima, N., Gabriel, K. J., Ozaki, M., Takahashi, J., Horiguchi, H., and Fujita, H., "Electrostatic Parallelogram Actuators," Proceedings of Transducers '91, the 1991 International Conference on Solid-State Sensors and Actuators, IEEE Press, San Francisco, CA, June 24-27, 1991, pp.188-191,

33. Tabata, O., Kawahata, K, Sugiyama, S. and Igarashi, I., "Mechanical Property Measurements of Thin Films Using Load-Deflection of Composite Rectangular Membrane," An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots, Proceedings, pp.152-156, 1989

34. Tufte, O. N., Chapman, P. W. and Long, D., "Silicon Diffused-Element Piezoresistive Diaphragms," Journal of Applied Physics, Vol. 33, No. 11, pp.3322-3327, 1962

35. Van Mullem, C. J., Gabriel, K. J., and Fujita, H. "Large Deflection Performance of Surface Micromachined Corrugated Diaphragms," Proceedings of Transducers '91, the 1991International Conference on Solid-State Sensors and Actuators, San Francisco, CA, June 24-27, 1991, pp.188-191,

36. Wu, T. H. T. and Rosler R. S., "Stress in PSG and Nitride Films as Related to Film Properties and Annealing," Solid State Technol., May, pp. 65-71, 1992

37. Xin Zhang, Tong-Yi Zhang, Man Wong, Yitshak Zohar, "Residual-Stress relaxation in polysilicon thin films by high-temperature rapid thermal annealing," Sens. Actuators, vol. A64, pp. 109-115, 1998

38. Yee, Y., Chun, K., Lee, J. D., and Kim, C.-J., "Polysilicon surface modification technique to reduce sticking of microstructures," Sens. Actuators, vol. A52, nos. 1-3, pp. 145-150, Apr. 1996

39. 葉武振, "微壓力感測器的研究與發展," M. S. thesis, National Cheng Kung University, Taiwan, Republic of China (2000).

40. 廖木桂, "微壓力感測器之薄膜形變," M. S. thesis, National Cheng Kung University, Taiwan, Republic of China (2001).