Automotive Tire Pressure Sensors with Titanium Membrane

Title & Authors
Automotive Tire Pressure Sensors with Titanium Membrane
Chae, Soo;

Abstract
In this work, mechanical characteristics of titanium diaphragm have been studied as a potential robust substrate and a diaphragm material for automotive tire pressure sensor. Lamination process techniques combined with traditional micromachining processes have been adopted as suitable fabrication technologies. To illustrate these principles, capacitive pressure sensors based on titanium diaphragm have been designed, fabricated and characterized. The fabrication process for micromachined titanium devices keeps the membrane and substrate being at the environment of 20 MPa pressure and $\small{200^{\circ}C}$ for a half hour and then subsequently cooled to $\small{24^{\circ}C}$. Each sensor uses a stainless steel substrate, a laminated titanium film as a suspended movable plate and a fixed, surface micromachined back electrode of electroplated nickel. The finite element method is adopted to investigate residual stresses formed in the process. Besides, out-of-plane deflections are calculated under pressures on the diaphragm. The sensitivity of the fabricated device is $\small{9.45ppm\;kPa^{-1}}$ with a net capacitance change of 0.18 pF over a range 0-210 kPa.
Keywords
Capacitance;Finite Element Method;Micromachining;Pressure Sensor;Titanium;
Language
Korean
Cited by
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