Structure and manufacturing method of beam-island-membrane integrated resonant pressure sensor

Abstract

The invention relates to a beam-island-diaphragm integrated resonant pressure sensor structure and a manufacturing method thereof and aims at providing a beam-island-diaphragm integrated resonant pressure sensor structure and a manufacturing method thereof. The beam-island-diaphragm integrated resonant pressure sensor structure comprises a resonant beam, a pressure-sensitive diaphragm and two silicon islands arranged on the pressure-sensitive diaphragm; the resonant beam is arranged between the two silicon islands; and an excitation resistor and a piezoresistor are formed on the resonant beam.The pressure-sensitive diaphragm, the silicon islands, and the resonant beam are formed by corrosion with an anisotropic etching solution of a silicon wafer with the surface (100); the silicon waferis corroded in the anisotropic etching solution to form the pressure-sensitive diaphragm and the silicon islands and the silicon below the resonant beam is corroded from the surface (111) to release the resonant beam along the (110) crystal orientation, so that an integrated beam-island-diaphragm structure is formed. The resistivity of the silicon wafer is less than 0.1omega.cm; and the doping concentration is less than the self-stop corrosion concentration. The beam-island-diaphragm integrated resonant pressure sensor structure and the manufacturing method thereof are suitable for the MEMS field.

Description

technical field [0001] The invention relates to a beam-island-membrane integrated resonant pressure sensor structure and a manufacturing method. Applicable to the field of microelectromechanical systems (MEMS). Background technique [0002] The resonant pressure sensor is a type of sensor based on the change of the resonant frequency of the resonator as the pressure changes. The measured pressure causes the equivalent stiffness of the resonator to change, thereby changing the resonant frequency of the resonator, and the measured pressure is obtained by measuring the change of the resonant frequency. As the core component of the resonant pressure sensor, the resonator works in the state of mechanical resonance, and the output frequency signal is not affected by the circuit noise. The signal-to-noise ratio and resolution are high, and the anti-interference ability is strong. It is easy to connect with the field bus and can save the price. Expensive A / D conversion device redu...

AI Technical Summary

Problems solved by technology

The latter requires the resonant beam to be along the crystal direction, which is not conducive to arranging the varistor

At present, the beam-island-membrane integrated structural resonant pressure sensor adopts the electrostatic excitation / capacitance detection mode. When the pressure-sensitive diaphragm is deformed under pressure, the electrode gap between the excitation capacitance and the detection capacitance will change, so that the excitation force and detection The signal produces nonlinear changes, which increases the difficulty of closed-loop control

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