Curved high-overload resonant micro-accelerometer chip

Abstract

The invention discloses a curved high-overload resonant micro-accelerometer chip. The curved high-overload resonant micro-accelerometer chip consists of a silicon substrate and quartz tuning fork beams, wherein the silicon substrate comprises a sensitive mass block; the sensitive mass block and a support framework are connected into a whole through a flexible support beam and mounting support beams; mounting empty grooves and mounting alignment marks are etched on the sensitive mass block; two mounting alignment marks are arranged on the support framework; the quartz tuning fork beams are mounted above the mounting empty grooves; quartz beam bases at two ends of the quartz tuning fork beams are aligned with the mounting alignment marks respectively; electrodes are sputtered on four sides of the quartz tuning fork beams, and applied to excitation of the quartz tuning fork beams; the quartz beam bases are connected with an external circuit; an overload structure on the support frameworkis matched with an overload structure on the sensitive mass block to protect the flexible support beam and the quartz tuning fork beams from being damaged under an overload condition; a frequency difference between the two quartz tuning fork beams is proportional to an acceleration; and a difference value between frequencies is measured to obtain a numerical value of the acceleration. The curved high-overload resonant micro-accelerometer chip has the advantages of high accuracy, small size, batch production and the like.

Description

technical field [0001] The invention belongs to the technical field of micro-mechanical electronics (MEMS) digital accelerometers, and in particular relates to a resonant micro-accelerometer chip with high curve overload. Background technique [0002] Current resonant accelerometers are mostly based on pure silicon or quartz materials. Silicon material has good mechanical properties, which can ensure product accuracy, low cost and mass production. However, for resonant accelerometers using silicon materials, their excitation and detection methods are relatively fixed, and silicon itself has no piezoelectric properties. It is necessary to use electrostatic force, thermal expansion force, deposition of other piezoelectric materials, electromagnetic force and other means to excite the resonator to vibrate, which is easy to introduce noise interference and limit the further improvement of precision. Quartz crystal has piezoelectric properties, and can be easily excited by the e...

AI Technical Summary

Problems solved by technology

Silicon material has good mechanical properties, which can ensure product accuracy, low cost and mass production. However, for resonant accelerometers using silicon materials, their excitation and detection methods are relatively fixed, and silicon itself has no piezoelectric properties. It is necessary to use electrostatic force, thermal expansion force, deposition of other piezoelectric materials, electromagnetic force and other means to excite the resonator to vibrate, which is easy to introduce noise interference and limit the further improvement of precision

Quartz crystal has piezoelectric properties, and can be easily excited by the excitation circuit through a reasonable cutting shape design and electrode arrangement, and has a high quality factor. The lattice structure is complex, and the micromachining process is difficult

Therefore, most of the existing resonant accelerometers have problems such as poor resistance to overload impact, analog output, low sensitivity, and complicated processing due to the defects of the material itself.

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