Skip to main content
×
×
Home

A fabrication process based on structural layer formation using Au–Au thermocompression bonding for RF MEMS capacitive switches and their performance

  • Cagri Cetintepe (a1), Ebru Sagiroglu Topalli (a2), Simsek Demir (a1), Ozlem Aydin Civi (a1) and Tayfun Akin (a1) (a2)...
Abstract

This paper presents a radio frequency micro-electro-mechanical-systems (RF MEMS) fabrication process based on a stacked structural layer and Au–Au thermocompression bonding, and reports on the performance of a sample RF MEMS switch design implemented with this process. The structural layer consists of 0.1 µm SiO2/0.2 µm SixNy/1 µm Cr–Au layers with a tensile stress less than 50 MPa deposited on a silicon handle wafer. The stacked layer is bonded to a base wafer where the transmission lines and the isolation dielectric of the capacitive switch are patterned. The process flow does not include a sacrificial layer; a recess etched in the base wafer provides the air gap instead. The switches are released by thinning and complete etching of the silicon handle wafer by deep reactive ion etching (DRIE) and tetramethylammonium hydroxide (TMAH) solution, respectively. Millimeter-wave measurements of the fabricated RF MEMS switches demonstrate satisfactory up-state performance with the worst-case return and insertion losses of 13.7 and 0.38 dB, respectively; but the limited isolation at the down-state indicates a systematic problem with these first-generation devices. Optical profile inspections and retrospective electromechanical analyses not only confirm those measurement results; but also identify the problem as the curling of the MEMS bridges along their width, which can be alleviated in the later fabrication runs through proper mechanical design.

Copyright
Corresponding author
Corresponding author: C. Cetintepe Email: ccagri@metu.edu.tr
References
Hide All
[1]Rebeiz, G.M. et al. : Tuning in to RF MEMS. IEEE Microw. Mag., 10 (6) (2009), 5572.
[2]Lucyszyn, S.: Review of radio frequency microelectromechanical systems technology. IEE Proc. Sci. Meas. Technol., 151 (2) (2004), 93103.
[3]van Spengen, W.M.: Capacitive RF MEMS switch dielectric charging and reliability: a critical review with recommendations. J. Micromech. Microeng., 22 (7) (2012), 074001.
[4]Toler, B.F.; Coutu, R.A. Jr.; McBride, J.W.: A review of micro-contact physics for microelectromechanical systems (MEMS) metal contact switches. J. Micromech. Microeng., 23 (10) (2013), 103001.
[5]Huang, Y.; Vasan, A.S.S.; Doraiswami, R.; Osterman, M.; Pecht, M.: MEMS reliability review. IEEE Trans. Device Mater. Rel., 12 (2) (2012), 482493.
[6]Goldsmith, C.L.; Hwang, J.C.M.; Gudeman, C.; Auciello, O.; Ebel, J.L.; Newman, H.S.: Robustness of RF MEMS capacitive switches in Harsh Environments, in 2012 IEEE Int. Microwave Symp. Digest, 2012, 1–3.
[7]Tilmans, H.A.C. et al. : MEMS packaging and reliability: an undividable couple. Microelectron. Reliab., 52 (9–10) (2012), 22282234.
[8]Goldsmith, C. et al. : Charging characteristics of ultra-nano-crystalline diamond in RF MEMS capacitive switches, in 2010 IEEE Int. Microwave Symp. Digest, 2010, 1246–1249.
[9]Chen, L. et al. : Contact resistance study of noble metals and alloy films using a scanning probe microscope test station. J. Appl. Phys., 102 (7) (2007), 074910.
[10]Palego, C. et al. : Robustness of RF MEMS capacitive switches with molybdenum membranes. IEEE Trans. Microw. Theory Techn., 57 (12) (2009), 32623269.
[11]Hsu, H.; Koslowski, M.; Peroulis, D.: An experimental and theoretical investigation of creep in ultrafine crystalline nickel RF-MEMS devices. IEEE Trans. Microw. Theory Tech., 59 (10) (2011), 26552664.
[12]Forehand, D.I.; Goldsmith, C.L.: Zero-level packaging for RF MEMS switches, in 2006 Govt Microcircuit Applications and Critical Tech Conf., San Diego, CA, 2006, 36–39.
[13]Maciel, J.; Majumder, S.; Lampen, J.; Guthy, C.: Rugged and reliable ohmic MEMS switches, in 2012 IEEE Int. Microwave Symp. Digest, 2012, 1–3.
[14]Topalli, K.; Civi, O.A.; Demir, S.; Koc, S.; Akin, T.: A monolithic phased array using 3-bit distributed RF MEMS phase shifters. IEEE Trans. Microw. Theory Tech., 56 (2) (2008), 270277.
[15]Topalli, K.; Erdil, E.; Civi, O.A.; Demir, S.; Koc, S.; Akin, T.: Tunable dual-frequency RF MEMS rectangular slot ring antenna. Sens. Actuators: A, 156 (2) (2009), 373380.
[16]Cetintepe, C.: Development of MEMS Technology Based Microwave and Millimeter-Wave Components. M.Sc. thesis, Middle East Technical University, Ankara, Turkey, 2010.
[17]Min, B.W.; Rebeiz, G.M.: A low-loss silicon-on-silicon DC-110-GHz resonance-free package. IEEE Trans. Microw. Theory Tech., 54 (2) (2006), 710716.
[18]Milanovic, V.; Maharbiz, M.; Pister, K.S.J.: Batch transfer integration of RF microrelays. IEEE Microw. Guid. Wave Lett., 10 (8) (2000), 313315.
[19]Huang, S.; Zhang, X.: Gradient residual stress induced elastic deformation of multilayer MEMS structures. Sens. Actuators A: Phys., 134 (1) (2007), 177185.
[20]Liu, R. et al. : Elimination of initial stress-induced curvature in a micromachined bi-material composite-layered cantilever. J. Micromech. Microeng., 23 (9) (2013), 095019.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

International Journal of Microwave and Wireless Technologies
  • ISSN: 1759-0787
  • EISSN: 1759-0795
  • URL: /core/journals/international-journal-of-microwave-and-wireless-technologies
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed