Quartz vibrating beam accelerometer sensitive chip based on gold-gold bonding

Abstract

The invention relates to a quartz vibrating beam accelerometer sensitive chip based on gold-gold bonding and relates to the processing field of the quartz vibrating beam accelerometer sensitive chip. The sensitive chip comprises a sensitive unit layer, an upper protection unit layer and a lower protection unit layer, wherein the upper protection unit layer is arranged at an upper surface of the sensitive unit layer, the lower protection unit layer is arranged at the upper surface of the sensitive unit layer, the upper surface of the sensitive unit layer is equipped with a first sealing ring, a lower surface of the sensitive unit layer is fixedly equipped with a second sealing ring, a lower surface of the upper protection unit layer is fixedly equipped with a third sealing ring, an upper surface of the lower protection unit layer is fixedly equipped with a fourth sealing ring, one side of the upper protection unit layer is symmetrically provided with two square holes, and the upper surface of the lower protection unit layer is symmetrically provided with two bosses at the corresponding position. The sensitive chip is advantaged in that a problem of compatibility difficulty caused by airtight packaging and internal electrodes is effectively solved, excellent portability is realized, and the sensitive chip can be applied to the preparation process of MEMS devices taking quartz, silicon and glass materials as base materials.

Description

technical field [0001] The invention relates to the field of hermetic packaging of a sensitive chip of a quartz vibrating beam accelerometer, in particular to a sensitive chip of a quartz vibrating beam accelerometer based on gold-gold bonding. Background technique [0002] Quartz vibrating beam accelerometer is a sensor that uses the resonant measurement principle to convert the measured acceleration into the natural frequency change of the quartz vibrating beam. It has the advantages of large range, high precision, small size, low power consumption, and quasi-digital output. It is widely used in low-cost integrated navigation system, antenna platform stabilization system, oil drilling, seismic survey and other fields. [0003] Classified from the structure of the sensitive chip, the quartz vibration beam accelerometer includes two types: integrated type and split type. The split type is mainly made of quartz vibration beam and metal pendulum structure. Its typical product ...

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Problems solved by technology

[0004] At present, the hermetic packaging process of the sensitive chip of the integrated quartz vibrating beam accelerometer is based on the chip, including multi-layer microstructure assembly, patch, lead, sealing and other processes, and the MEMS front-end processing technology such as optical fiber is based on the sensitive chip. Compared with engraving, etching, etc., the production and screening efficiency of the packaging process has limited room for improvement; the microstructure assembly of sensitive chips is mainly the assembly of sensitive units and upper and lower protection units. Repeatability and long-term reliability, at the same time, due to the fluidity of epoxy glue before curing, it may cause sideslip between layers, resulting in poor alignment accuracy between layers; the sealing of sensitive chips can reduce environmental interference and ensure The chip works in a stable resonance state. Some manufacturers, such as French Thales and Sagem, use vacuum sealing to further improve the Q value of sensitive chips to achieve excellent zero bias stability and resolution indicators. The packaging method is mainly based on the metal tube shell vacuum welding process. This method has high technical maturity, but the size of the metal shell obtained by cutting or stamping is relatively large, which obviously weakens the miniaturization and integration advantages of the integrated quartz beam accelerometer sensitive chip

[0005] In response to the shortcomings of the traditional "chip-level" packaging process, the French space agency ONERA proposed a "sensitive chip-level" packaging process based on quartz-silicon fusion bonding technology, that is, sensitive chip packaging is realized in units of sensitive chips, and MEMS is mass-produced The advantage of this method extends to the packaging stage, and at the same time, it can realize the hybrid integration of quartz-sensitive chips and silicon microchips, but there are three main problems in this solution: First, the quartz-silicon fusion bonding technology has a negative effect on the surface roughness and cleanliness of sensitive chips. The requirements are extremely high, and it is difficult to meet the sensitive chips after the previous process; second, the difference in thermal expansion coefficient between quartz and silicon materials limits the full temperature stability of sensitive chips; third, the contradiction between internal electrode leads and vacuum sealing is not easy Resolved that internal electrodes passing through a quartz-silicon bonded seal ring would create challenges for a low leak rate vacuum seal

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