Ultraviolet-Assisted Release of Microelectromechanical Systems From Polyimide Sacrificial Layer
Javaneh Boroumand Azad, Imen Rezadad, Robert E. Peale, Justin W. Cleary, and Kurt Eyink
Process heating of microelectromechanical systems (MEMSs) devices hardens polyimide sacrificial layers, complicating the final release and lowering yield for delicate structures. This paper reports ultraviolet (UV)-assisted release, which is demonstrated on an MEMS cantilever fabricated by an eight-mask photolithographic process. A commercial co-developable polyimide ProLift 100 (Brewer Science) sacrificial layer was used. The process subjects the device to multiple heat treatment steps. Both wet chemical etching and dry reactive ion etching were explored. During the former, large sheets of hardened polyimide floated free of the substrate to damage delicate MEMS structures. The latter is typically slow, so that grass appears during long exposures to plasma ions. The solution reported here is UV exposure prior to release. Optical constants of the sacrificial layer material, which were baked to simulate thermal histories during various fabrication steps, were measured to understand the effectiveness of UV exposure. Wet and dry etch rates were measured as a function of UV dose. Finally, the advantages of UV pretreatment were demonstrated during the release of actual MEMS cantilevers.
Ultraviolet-Assisted Release of Microelectromechanical Systems From Polyimide Sacrificial Layer
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2015
Javaneh Boroumand Azad, Imen Rezadad, Robert E. Peale, Justin W. Cleary, and Kurt Eyink, Ultraviolet-Assisted Release of Microelectromechanical Systems From Polyimide Sacrificial Layer, J. Microelectricalmechanical Systems 24(6) 2027-2032 (2015).
Farnood Khalilzadeh-Rezaie, Christian W. Smith, Janardan Nath, Nima Nader, Monas Shahzad, Justin W. Cleary, Ivan Avrutsky, and Robert E. Peale, Infrared surface polaritons on bismuth, J. Nanophotonics 9, 093792 (2015).
2014
Deep Panjwani, Mehmet Yesiltas, Janardan Nath, D. E. Maukonen, Imen Rezadad, Evan M. Smith, R. E. Peale, Miriam Unger, Julia Sedlemair, Ralf Wehlitz, Carol Hirschmugl, Glenn Boreman, Patterning of oxide-hardened gold black by photolithography and metal lift-off, Infrared Physics & Technology 62, 94-99 (2014).
Janardan Nath, Evan Smith, Douglas Maukonen, and Robert E. Peale, Optical Salisbury screen with design-tunable resonant absorption bands, J. Applied Physics 115, 193103 (2014).
D. Panjwani, M. Yesiltas, S. Singh, E.D. Barco, R.E. Peale, C. Hirschmugl, J. Sedlemair, Stencil lithography of gold-black IR absorption coatings, Infrared Physics & Technology 66, 1-5 (2014), doi:http://dx.doi.org/10.1016/j.infrared.2014.05.002
Imen Rezadad, Javaneh Boroumand, Evan M. Smith, and Robert E. Peale, Micro electro mechanical cantilever with electrostatically controlled tip contact, Appl. Phys. Lett. 105, 033514 (2014) http://dx.doi.org/10.1063/1.4891496.
2013
N. Nader Esfahani, R. E. Peale, W. R. Buchwald, C. J. Fredricksen, J. R. Hendrickson, and J. W. Cleary, Millimeter-wave photoresponse due to excitation of two-dimensional plasmons in InGaAs/InP high-electron-mobility transistors, J. Appl. Phys. 114, 033105 (2013).
2012
Justin W. Cleary, Gautam Medhi, Monas Shahzad, Imen Rezadad, Doug Maukonen, Robert E. Peale, Glenn D. Boreman, Sandy Wentzell, and Walter R. Buchwald, Infrared surface polaritons on antimony, Optics Express 20 (3), 2693-2705 (2012).