Source:Micro Electro Mechanical Systems (MEMS), 2012 IEEE 25th International Conference on , ieeexplore.ieee.org, p.309-312 (2012)
Keywords:2012, 2013 and earlier, acoustic MEMS, additive fabrication, Cavity resonators, deep reactive ion etching, dielectric layer, Electrodes, Gold, MEMS diaphragms, micromechanical devices, optical interferometry, organic film, patterned silicon dioxide substrates, printed MEMS membranes, Resists, Silicon, sputter etching, Substrates, thin gold membranes, wafer bonding, Young modulus
We report a new method for additive fabrication of thin (125±15 nm thick) gold membranes on patterned silicon dioxide (SiO2) substrates for acoustic
MEMS. The deflection of these membranes, suspended over cavities in a SiO2
dielectric layer atop a conducting electrode, can be used to produce
sounds or monitor pressure. This process uses a novel technique of
dissolving an underlying organic film using acetone to transfer membranes
onto SiO2 substrates. The process avoids fabrication of MEMS diaphragms
via wet or deep reactiveion etching, which in turn removes the need for
etch-stops and wafer bonding. Membranes up to 0.78 mm2 in area are
fabricated and their deflection is measured using optical interferometry.
The membranes have a maximum deflection of about 150 nm across 28 μm
diameter cavities. Young's modulus of these films is shown to be 74±17
GPa, and their potential sound pressure generation at 15 V is calculated.