1. micromachined multi-sensors
H. Benalia a , J-Y. Rauch b, B. Serio c, D. Vernier b , P. Nika a
a Institut FEMTO-ST UMR 6174 Dep CREST . 2 Av Jean Moulin Belfort.
b Institut FEMTO-ST UMR 6174 Dep LPMO . 32 Av de l’Observatoire Besançon Cedex.
c Laboratoire des systèmes photoniques, ULP-ENSPS, Bd sébastien Brant, Illkirch cedex.
HARMST 2007
Centre National de la Recherche Scientifique
Longer Silicon cantilever beams development and fabrication for the design of a fluidic
micromachined multi-sensors
Abstract:
The aim of this work is the cantilever beam development and the realization with a low aspect ratio in order to design fluidic multi-sensors, this sensor will be able to measure acoustical intensity in an oscillating flow. The multi-sensors could be used in experimentally pressure and temperature oscillation study in thermostatic resonance tube. Since the micro-sensor will be placed at the center of the tube. The measure principle is the characterization of the micro-beams deformation (placed in the center of the flow) with a thin film strain gauge. The temperature measure by integrated thermocouple (Si/Al) at the cantilever beams.
Simulation results and fabrication process :
Figure 1 : Deflection influence with speed flow and thickness
cantilever beams
Figure 2 : Process fabrication of the cantilever beams
The innovation of this work is the process clarification of the cantilever beams fabrication (D-RIE), permitting a longer cantilevers beams (length = 15mm) and very thin (200µm) for optimized deformations.
Figure 1 shows theoretical evolutions of the beam deformation amplitude according to the flow axial velocity for several beam thicknesses. Figure 2 presents the clean room process used to etch deep cavities in the silicon substrate. It based on two successive steps of deep reactive ion etching (D-RIE).
Simples pictures:
Figure 3: The picture of the high micromachined silicon beam cantilever : 1.5 mm width, 200 μm thickness, 15 mm length.
Conclusion:
We developed a high cantilever beams fabrication process, using deep reactive ion etching technique. The cantilever beams can be used to dynamic flow measurement. We can use the same technique to fabricate thinner structures for higher sensiblility.