Pressure sensor utilizing electrostatic negative stiffness and production method of pressure sensor

Abstract

The invention discloses a pressure sensor utilizing electrostatic negative stiffness and a production method of the pressure sensor. The pressure sensor comprises a pressure-sensitive layer, a cantilever-type resonance layer, a vacuum-sealed cover layer and electrodes from bottom to top. The production method includes taking photoresist as a mask to process an electrode hole and a lead gap on a glass sheet, and connecting the electrode hole and the lead gap with a silicon wafer to etch out a drive silicon electrode and a detect silicon electrode; reserving a mask window in a metal mask or a silicon oxide prior to etching out blind grooves both on the top and bottom surfaces of the cantilever-type resonance layer; etching out the lead gap of the cantilever-type resonance layer and a cantilever beam with a mass; taking the silicon oxide layer and a silicon nitride layer as masks to etch out a pressure-sensitive film and a grounding electrode which are single-sided to produce the pressure-sensitive layer; connecting both the upper end and the lower end of the cantilever-type resonance layer to form a combined piece prior to connecting with the vacuum-sealed cover layer to form a three-layer combined piece; mounting the three-layer combined piece to a hard board jig; producing a metal layer covering the grounding electrode and a lead electrode of the drive silicon electrode by means of spurting and evaporating so as to form the sensor finally.

Description

technical field [0001] The invention relates to a pressure sensor, in particular to a pressure sensor utilizing electrostatic negative stiffness and a manufacturing method thereof. Background technique [0002] The silicon microresonant pressure sensor based on micro-electromechanical (MEMS) technology is currently the most accurate silicon micro-pressure sensor. It indirectly measures the pressure by detecting the change of the natural frequency of the microstructure, and outputs a quasi-digital signal. It can be directly connected to the computer. It is also easy to form an instrument that directly displays numbers. The accuracy of the silicon microresonant sensor is mainly affected by the mechanical characteristics of the vibrating structure, so it has a strong ability to resist electronic interference and stable performance. In addition, silicon microresonant pressure sensors also have many advantages such as fast response, wide frequency range, low power consumption, c...

AI Technical Summary

Problems solved by technology

The above working principles make this type of resonant structure at least double-ended or even multi-terminal fixed, which will make it difficult for the quality factor of this type of structure to reach the level of 100,000 that can be achieved by a cantilever beam resonant structure.

Another important problem with this type of resonant structure is that changes in temperature will cause deformation of the pressure sensitive membrane, which will eventually affect the resonant frequency of the output, resulting in temperature errors in pressure measurement, which increases the difficulty of designing high-precision pressure sensors.

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