Reverse Lift-Off Process and Application for Cu-Zr-Ti Metallic Glass Thick Film Structures
Shigetaka Watanabe, Junpei Sakurai, Mizue Mizoshiri, and Seiichi Hata
Graduate School of Engineering, Nagoya University
Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
In technologies involving micro electromechanical systems, lift-off processes combined with sputter deposition are general patterning methods for the formation of amorphous alloy thick film structures. However, the thicknesses of structures fabricated in this manner are not uniform because sputtered particles are blocked by the sidewalls of the lift-off layer. In this paper, a reverse lift-off process is proposed as a new patterning method for fabricating amorphous alloy thick film structures of uniform thickness. In the reverse lift-off process, a template of the desired structure is formed on top of the chosen substrate. The thick film structure is then formed by sputter deposition on the top surface of the template. In contrast to a conventional lift-off process, here the thickness of the structure is uniform because there is nothing to hinder the sputtered particles. To demonstrate this process, we successfully fabricated a Cu-Zr-Ti metallic glass thick film structure with a uniform film thickness and a rectangular cross section across different target structure widths and thicknesses. This demonstrates that the reverse lift-off process is more suitable than conventional lift-off processes for the fabrication of metallic glass thick film structures.
-  J. Tregilgas, “How We Developed an Amorphous Hinge Material,” AM&P, pp. 46-48, 2005.
-  E. Quandt, “Multitarget sputtering of high magnetostrictive TbDyFe films,” J. Appl. Phys., Vol.75, No.10, pp. 5563-5655, 1994.
-  Y. Liu, S. Hata, K. Wada, and A. Shimokohbe, “Thermal, mechanical and electrical properties of Pd-based thin film metallic glass,” Jpn. J. Appl. Phys., Vol.40, No.9R, pp. 5382-5388, 2001.
-  H. W. Jeong and S. Hata, “Microforming of Three-Dimensional Microstructures from Thin-Film Metallic Glass,” J. Microelectromech. Syst., Vol.12, No.1, pp. 42-52, 2003.
-  Y. Yokoyama, T. Fukushige, S. Hata, K. Masu, and A. Shimokohbe, “On-Chip Variable Inductor Using Microelectromechanical Systems Technology,” Jpn. J. Appl. Phys., Vol.42, No.4S, pp. 2190-2192, 2003.
-  D. Sun, S. Wang, J. Sakurai, K. B. Choi, A. Shimokohbe, and S. Hata, “A Piezoelectric Linear Ultrasonic Motor with the Structure of a Circular Cylindrical Stator and Slider,” Smart Mater. Struct., Vol.19, No.4, 045008, 9pp., 2010.
-  S. Watanabe, J. Sakurai, and S. Hata, “Compound Micro Process for Micro Mirror Device,” JSME 18th Int. Conf. on Materials and Processing, lecture number 139, 2010.
-  J. Moulin, M. Woytasik, I. Shahosseini, and F. Alves, “Micropatterning of Sandwiched FeCuNbSiB/Cu/FeCuNbSiB for the Realization of Magneto-impedance Microsensors,” Microsyst. Technol., Vol.17, No.4, pp. 637-644, 2011.
-  J. Melai, C. Salm, R. Wolters, and J. Schmitz, “Qualitative and quantitative characterization of outgassing from SU-8,” Micro. Eng., Vol.86, No.4, pp. 761-764, 2009.
-  J. Eckert, N. Mattern, M. Zinkevitch, and M. Seidel, “Crystallization Behavior and Phase Formation in Zr-Al-Cu-Ni Metallic Glass Containing Oxygen,” Mater. Trans. JIM., Vol.39, No.6, pp. 623-632, 1998.
-  T. Yamazaki, T. Yoshizawa, T. Yamabuchi, S. Hirobayashi, T. Kikuta, N. Nakatani, and T. Mizuguchi, “Slit Structure as a Countermeasure for the Thermal Deformation of a Metal Mask,” Jpn. J. Appl. Phys., Vol.40, pp. 7170-7173, 2001.
-  S. Watanabe, J. Sakurai, and S. Hata, “Fabrication of Cu-Zr-Ti Thick Film Structure of Metallic Glass by Double Metal Mask Lift-off Process,” Microel. Eng., Vol.135, No.5, pp. 45-51, 2015.
-  S. Nakamura, Y. Nakamura, M. Ataka, and H. Fujita, “A Study on Patterning Method of TiNi Shape Memory Thin Film,” Trans. on IEE of Japan, Vol.117-E, No.1, pp. 27-32, 1997.
-  W. Moreau, “Semiconductor Lithography: Principles, Practices, and Materials,” Plenum Press, 1988.
-  H. I. Smith, “Fabrication techniques for surface-acoustic-wave and thin-film optical devices,” IEEE Proc., Vol.62, pp. 1361-1387, 1974.
-  K. Fujita, T. Hashimoto, W. Zhang, N. Nishiyama, C. Ma, H. Kimura, and A. Inoue, “Fatigue Strength in Nanocrystalline Ti- and Cu-Based Bulk Metallic Glasses,” J. Japan Inst. Metals, Vol.70, No.10, pp. 816-823, 2006.
-  A. Inoue, W. Zhang, T. Zhang, and K. Kurosaka, “High-Strength Cu-Based Bulk Glassy Alloys in Cu-Zr-Ti And Cu-Hf-Ti Ternary Systems,” Acta Mater., Vol.49, pp. 2645-2652, 2001.
-  Y. M. Shin, D. Gamzina, L. R. Barnett, F. Yaghmaie, A. Baig, and N. C. Luhmann, “UV Lithography and Molding Fabrication of Ultrathick Micrometallic Structures Using a KMPR Photoresist,” J. Microelectromechanical Systems, Vol.19, No.3, 2010.
-  M. D. Ynsa, P. Shao, S. R. Kulkarni, N. N. Liu, and J. A. van Kan, “Exposure parameters in proton beam writing for KMPR and EPO Core negative tone photoresists,” Nucl. Instrum. Meth., B, Vol.269, Issue 20, pp. 2409-2412, 2011.
-  C. O’Mahony, M. Hill, M. Brunet, R. Duane, and A. Mathewson, “Characterization of micromechanical structures using white-light interferometry,” Meas. Sci. Technol., Vol.14, pp. 1807-1814, 2003.
This article is published under a Creative Commons Attribution-NoDerivatives 4.0 Internationa License.