%0 PDF %T Low Profile Packaging for MEMS Aero-Acoustic Sensors. %A Burns, John. %8 2017-04-19 %R http://localhost/files/cf95jp79z %X Abstract: This thesis explores both a semi-automated conductive ink process and modifications to Draper Laboratory's i-UHD (Integrated - Ultra High Density) process for packaging MEMS devices. These methods are applied to packaging MEMS acoustic sensors for wind tunnel testing. The primary advantage of these methods is a reduction in surface topology between the package and the integrated MEMS sensors. In these particular applications, the sensor records surface pressure and shear stress under the turbulent boundary layer. In order to avoid self-noise effects or other modifications to the boundary layer structure associated with surface roughness, the interface between the MEMS sensor and its package must be as close to planar as possible. The thickness of the viscous sub layer below the turbulent boundary layer is the upper bound on allowable surface topology. For wind tunnel flows at free stream velocities between 20 and 200 m/s and plate lengths on the order of half a meter, the Reynolds number is between 105 and 107. This suggests that the viscous wall unit will be on the order of 1 to 35 micrometers. The viscous sub layer is approximately 5 wall units thick, so surface topologies of between 5 and 175 micrometers are desired [1]. A previous packaging approach using gold wire bonds with Computer Numerical Controlled (CNC) machined epoxy fill resulted in a minimum surface topology of greater than 100 micrometers. In addition, for large arrays of MEMS microphones, yield issues were dominated by wire bond integrity problems. These two issues were the primary motivation for using Draper's i-UHD process and developing the low profile conductive ink process. However, the process is generally useful and can be applied to the packaging of various types of sensor systems that require low profile interconnects.; Thesis (M.S.)--Tufts University, 2012.; Submitted to the Dept. of Mechanical Engineering.; Advisor: Robert White.; Committee: Robert White, Brian Smith, Livia Racz, and Anil Saigal.; Keywords: Packaging, Acoustics, and Mechanical engineering. %[ 2022-10-12 %9 Text %~ Tufts Digital Library %W Institution