Chip of Z-direction sensitive quartz vibration beam accelerometer based on quartz on silicon (QoS) technology, processing technology and accelerometer

Abstract

The invention provides a chip of a Z-direction sensitive quartz vibration beam accelerometer based on a quartz on silicon (QoS) technology, a processing technology and an accelerometer. The chip comprises a first quartz structure and a second quartz structure, wherein the first quartz structure and the second quartz structure are bonded on two sides of a silicon substrate structure; the quartz structures comprise quartz frames, two-end fixed quartz tuning forks, quartz supporting beams and quartz mas blocks; the silicon substrate structure comprises a silicon substrate frame and a silicon massblock; a sandwich form of the first quartz structure, the silicon substrate structure and the second quartz structure is formed and completely bonded at the quartz frame and the silicon substrate frame and the quartz mass block and the silicon mass block; and the processing technology comprises the steps that firstly, initial processing of the silicon substrate is carried out, then double-surfacebonding of the silicon substrate and two quartz pieces is carried out, the two quartz pieces are subjected to thinning and polishing, then quartz vibration beam electrodes and the quartz structures are manufactured, and finally the silicon substrate structure is released. The chip of the Z-direction sensitive quartz vibration beam accelerometer has the characteristics that the sensitivity is high, the cost is low and the like.

Description

technical field [0001] The invention belongs to the technical field of MEMS digital accelerometers, and in particular relates to a Z-direction sensitive quartz beam accelerometer chip based on a QoS (Quartz on Silicon) process, a processing technique and an accelerometer. Background technique [0002] The traditional quartz vibrating beam accelerometer is limited by the quartz processing technology, and can only use the wet etching process to realize the processing of the integrated quartz structure, and the wet etching is poor in precision control, and it is difficult to realize the precision of miniaturized, high-precision and complex structures. Reliable processing. Another solution is to adopt a split structure combining quartz vibrating beams and other substrate materials. The quartz vibrating beam is used as a sensitive element, and other substrate materials are used to process elastic elements. Commonly used substrate materials include silicon and metal. The general ...

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Problems solved by technology

The disadvantages of this method are: the precision of quartz wet etching is low, and it is difficult to make the structure smaller; secondly, micro-assembly after independent processing will introduce assembly errors. The state of the root vibrating beam is exactly the same, and there is often a large difference between the two beams due to pasting, which greatly reduces the effect of differential motion, and impurities such as water vapor in the glue will also affect the accuracy and stability of the accelerometer. In addition, due to the large difference in the thermal expansion coefficients of the two materials in the chip obtained by the split processing method, when the external environment temperature changes, thermal stress occurs in the axial direction of the quartz vibration beam, resulting in temperature drift of the accelerometer output

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