17 September 1996 Semiconductor acceleration sensor
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Proceedings Volume 2882, Micromachined Devices and Components II; (1996) https://doi.org/10.1117/12.250715
Event: Micromachining and Microfabrication '96, 1996, Austin, TX, United States
Abstract
This paper reports a practical semiconductor acceleration sensor especially suited for automotive air bag systems. The acceleration sensor includes four beams arranged in a swastika structure. Two piezoresistors are formed on each beam. These eight piezoresistors constitute a Wheatstone bridge. The swastika structure of the sensing elements, an upper glass plate and a lower glass plate exhibit the squeeze film effect which enhances air dumping, by which the constituent silicon is prevented from breakdown. The present acceleration sensor has the following features. The acceleration force component perpendicular to the sensing direction can be cancelled. The cross-axis sensitivity is less than 3 percent. And, the erroneous offset caused by the differences between the thermal expansion coefficients of the constituent materials can be canceled. The high aspect ratio configuration realized by plasma etching facilitates reducing the dimensions and improving the sensitivity of the acceleration sensor. The present acceleration sensor is 3.9 mm by 3.9 mm in area and 1.2 mm in thickness. The present acceleration sensor can measure from -50 to +50 G with sensitivity of 0.275 mV/G and with non-linearity of less than 1 percent. The acceleration sensor withstands shock of 3000 G.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Katsumichi Ueyanagi, Mitsuo Kobayashi, Tomoaki Goto, "Semiconductor acceleration sensor", Proc. SPIE 2882, Micromachined Devices and Components II, (17 September 1996); doi: 10.1117/12.250715; https://doi.org/10.1117/12.250715
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