阅读说明：本技术 一种抗干扰耐过载mems加速度计 (Anti-interference overload-resistant MEMS accelerometer ) 是由 王鹏 陈慧斌 何凯旋 黄斌 王帆 于 2019-08-27 设计创作，主要内容包括：本发明公开一种抗干扰耐过载MEMS加速度计,包括依次键合的衬底层、感应电极层、可动敏感结构层与盖帽,感应电极层包含感应电极中心锚点与两侧的感应电极,可动敏感结构层包含第一可动敏感结构中心锚点、第一实心可动敏感结构与第一空心可动敏感结构；感应电极底部设有硅支撑柱,硅支撑柱顶端与感应电极相连、底端与衬底层相连；第一可动敏感结构中心锚点、第一实心可动敏感结构与第一空心可动敏感结构上方分别对称键合有第二可动敏感结构中心锚点、第二实心可动敏感结构与第二空心可动敏感结构,第一空心可动敏感结构与第二空心可动敏感结构之间形成闭合的空腔；本加速度计能够降低外界环境对器件性能影响,提高器件的可靠性。(The invention discloses an anti-interference overload-resistant MEMS accelerometer, which comprises a substrate layer, an induction electrode layer, a movable sensitive structure layer and a cap, wherein the substrate layer, the induction electrode layer, the movable sensitive structure layer and the cap are sequentially bonded; the bottom of the induction electrode is provided with a silicon supporting column, the top end of the silicon supporting column is connected with the induction electrode, and the bottom end of the silicon supporting column is connected with the substrate layer; a second movable sensitive structure central anchor point, a second solid movable sensitive structure and a second hollow movable sensitive structure are symmetrically bonded above the first movable sensitive structure central anchor point, the first solid movable sensitive structure and the first hollow movable sensitive structure respectively, and a closed cavity is formed between the first hollow movable sensitive structure and the second hollow movable sensitive structure; the accelerometer can reduce the influence of the external environment on the performance of the device and improve the reliability of the device.)

1. The utility model provides an anti-interference is able to bear or endure MEMS accelerometer of transshipping, includes substrate layer, induction electrode layer, movable sensitive structure layer and the block that bonds in proper order, and induction electrode layer contains induction electrode center anchor point and the induction electrode of both sides, and movable sensitive structure layer contains first movable sensitive structure center anchor point, first solid movable sensitive structure and first hollow movable sensitive structure, its characterized in that, induction electrode bottom is equipped with the silicon support column, and the silicon support column top links to each other with induction electrode, and the bottom links to each other with the substrate layer, and induction electrode center anchor point bottom also links to each other with the substrate layer.

2. The MEMS accelerometer of claim 1, wherein a second movable sensitive structure central anchor point, a second solid movable sensitive structure and a second hollow movable sensitive structure are symmetrically bonded above the first movable sensitive structure central anchor point, the first solid movable sensitive structure and the first hollow movable sensitive structure, respectively, and a closed cavity is formed between the first hollow movable sensitive structure and the second hollow movable sensitive structure.

3. An anti-interference and overload-resistant MEMS accelerometer according to claim 1 or 2, wherein a vertical lead is arranged at one side of the cap, a vertical isolation ring is arranged at the periphery of the vertical lead, the bottom end of the vertical lead is connected with the substrate layer, and a wire bonding PAD is arranged at the top end of the vertical lead.

Technical Field

The invention relates to the technical field of micro-mechanical electronics, in particular to an anti-interference overload-resistant MEMS accelerometer.

background

MEMS (Micro-Electro-Mechanical Systems) is an abbreviation of Micro-Electro-Mechanical Systems, and MEMS manufacturing technology utilizes Micro-nano processing technology, especially related technology of semiconductor wafer manufacturing, to manufacture various Micro-nano Mechanical structures, and combines with Application Specific Integrated Circuit (ASIC) to form intelligent MEMS devices such as Micro-sensors, Micro-actuators, Micro-optical devices, etc. The MEMS component has the advantages of small volume, low cost, high reliability, low power consumption, high intelligent degree, easy calibration and easy integration, and is widely applied to aerospace, medical treatment, industrial production and various consumer-grade products.

At present, foreign high-performance MEMS accelerometer products are mature and widely applied in various aspects, high-performance MEMS accelerometers are deeply researched and developed in China, single-axis or multi-axis accelerometer products with high precision are prepared by some companies or laboratories, but the high-performance MEMS accelerometers are deficient in anti-interference and overload resistance, so that the application of the high-performance MEMS accelerometers in high-impact environments is limited to a certain extent.

The microstructure of a capacitive MEMS accelerometer typically comprises a sensitive structure and a sensing electrode structure. The MEMS accelerometer converts an acceleration signal into an electrical signal by sensing inertial forces caused by an input acceleration. As a force sensitive sensor, the stress generated by the change of the external temperature, the stress generated by the packaging process, the stress generated by the mismatching of materials and the internal stress generated by the micro-mechanical structure in the process of processing can all cause the deformation of the sensitive structure and the induction electrode, so that the capacitance at the left side and the right side is asymmetric, and for a high-performance accelerometer, the asymmetry of the capacitance at the left side and the right side has a large influence on the performance of the device.

Disclosure of Invention

The invention aims to provide an anti-interference and overload-resistant MEMS accelerometer, which can reduce the influence of the external environment on the performance of a device and improve the reliability of the device.

The technical scheme adopted by the invention for solving the technical problems is as follows:

An anti-interference overload-resistant MEMS accelerometer comprises a substrate layer, an induction electrode layer, a movable sensitive structure layer and a cover cap which are sequentially bonded, wherein the induction electrode layer comprises an induction electrode center anchor point and induction electrodes on two sides, and the movable sensitive structure layer comprises a movable sensitive structure center anchor point, a first solid movable sensitive structure and a first hollow movable sensitive structure; the bottom of the induction electrode is provided with a silicon supporting column, the top end of the silicon supporting column is connected with the induction electrode, the bottom end of the silicon supporting column is connected with the substrate layer, and the bottom of a central anchor point of the induction electrode is also connected with the substrate layer.

furthermore, a second movable sensitive structure central anchor point, a second solid movable sensitive structure and a second hollow movable sensitive structure are symmetrically bonded above the first movable sensitive structure central anchor point, the first solid movable sensitive structure and the first hollow movable sensitive structure respectively, and a closed cavity is formed between the first hollow movable sensitive structure and the second hollow movable sensitive structure.

furthermore, one side of the cap is provided with a vertical lead, the periphery of the vertical lead is provided with a vertical isolation ring, the bottom end of the vertical lead is connected with the substrate layer, and the top end of the vertical lead is provided with a lead bonding PAD.

The beneficial effect of the invention is that,

One, give up traditional response electrode and substrate in close contact with's structural style, adopt the silicon support column to support the response electrode, form accurate floated response electrode structure, this response electrode structure has cut off external disturbance almost completely and has reachd the transmission route of response electrode structure through the substrate for external disturbance descends by a wide margin to the influence of response electrode structure, thereby has guaranteed that the sensor has the symmetry of controlling both sides electric capacity under the circumstances of external disturbance, has improved the sensor interference killing feature.

Secondly, the movable sensitive structure of the existing accelerometer is generally of a solid structure on one side and an open hollow structure on the other side to form a differential structure, but the movable sensitive structure is only of a single-layer open hollow structure and is low in rigidity and weak in overload resistance, and the differential structure with the hollow one side and the solid one side can be formed by multiple processes, so that the process is complex; according to the invention, two layers of solid movable sensitive structures and hollow movable sensitive structures are adopted, a closed cavity is formed between the first hollow movable sensitive structure and the second hollow movable sensitive structure, and the rigidity of the movable sensitive structure is greatly improved due to the double-layer reinforcing structure, so that the overload resistance of the sensor is enhanced.

Drawings

The invention is further illustrated with reference to the following figures and examples:

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a top view of a substrate layer of the present invention;

FIG. 3 is an enlarged schematic view of the bonding of a substrate layer to an induction electrode layer in accordance with the present invention;

FIG. 4 is a top view of FIG. 3;

FIG. 5 is an enlarged view of the bonding of the sensing electrode layer and the movable sensitive structure layer according to the present invention;

Fig. 6 is an enlarged schematic view of the cap of the present invention.

Detailed Description

Referring to fig. 1 and 2, the present invention provides an anti-interference overload-resistant MEMS accelerometer, which includes a substrate layer, an inductive electrode layer, a movable sensitive structure layer, and a cap, which are bonded in sequence, wherein a substrate 11 of the substrate layer is provided with an insulating dielectric layer 12, a metal copper PAD point 13, a metal copper central anchor point 15, a left metal copper anchor point 17 and a right metal copper anchor point 16 located at two sides of the metal copper central anchor point 15, and the metal copper central anchor point 15, the left metal copper anchor point 17, and the right metal copper anchor point 16 are connected to the metal copper PAD point 13 through a metal copper lead 14, respectively.

Referring to fig. 3 and 4, the sensing electrode layer includes a sensing electrode central anchor point 22, a left sensing electrode 21, and a right sensing electrode 23, the bottoms of the left sensing electrode 21 and the right sensing electrode 23 are respectively provided with a silicon supporting pillar 24, the top end of the silicon supporting pillar 24 is connected with the sensing electrode, and the bottom end thereof is bonded with the left metal copper anchor point 17 and the right metal copper anchor point 16 of the substrate layer through a metal bonding layer 25; the bottom of the central anchor point 22 of the induction electrode is also bonded with the central anchor point 15 of the metal copper of the substrate layer through a metal bonding layer.

As shown in fig. 5, the movable sensitive structure layer includes a first movable sensitive structure central anchor point 37, a first solid movable sensitive structure 35 and a first hollow movable sensitive structure 39; a second movable sensitive structure central anchor point 32, a second solid movable sensitive structure 31 and a second hollow movable sensitive structure 34 are symmetrically bonded above the first movable sensitive structure central anchor point 37, the first solid movable sensitive structure 35 and the first hollow movable sensitive structure 39 respectively; the first hollow movable sensing structure 39 and the second hollow movable sensing structure 34 form a closed first cavity 34a and a closed second cavity 34b therebetween. Gaps 36 are formed between the first solid movable sensitive structure and the first hollow movable sensitive structure 39 and the left induction electrode 21 and the right induction electrode 23 of the induction electrode layer respectively. The movable sensitive structure layer is bonded with the sensing electrode central anchor point 22 through a third movable sensitive structure central anchor point 38 arranged at the bottom of the first movable sensitive structure central anchor point 37.

As shown in fig. 6, a vertical lead 42 is disposed on one side of the cap 41, a vertical isolation ring 46 is disposed on the periphery of the vertical lead 42, the bottom end of the vertical lead 42 is connected to the copper PAD 13 of the substrate layer, and a wire bonding PAD43 is disposed on the top end; the vertical wires 42 can lead out the signal of the substrate via the metallic copper PAD points 13 to the wire bond PAD43 of the cap; the top and bottom of the cap 41 and the inner wall of the vacuum chamber 45 are provided with insulating layers 44, and the insulating layers 44 prevent electric leakage between the electrodes.

When the environmental temperature changes, the packaging process, the residual stress of chip processing and the stress change caused by sensor installation, for the traditional MEMS accelerometer, the sensing electrode is tightly paved on the substrate, and the sensing electrode is also deformed due to the deformation of the substrate, so that the left and right capacitances of the accelerometer are asymmetric, and the output drift of the accelerometer is caused; in the MEMS accelerometer, the silicon supporting columns support the sensing electrodes to form a quasi-suspension type sensing electrode structure, when the substrate 11 deforms due to stress, the left sensing electrode 21 and the right sensing electrode 23 are supported and suspended on the substrate 11 through the silicon supporting columns, so that the left sensing electrode 21 and the right sensing electrode 233 cannot deform due to the deformation of the substrate 11, and the symmetry of left and right capacitors of the accelerometer is ensured, so that the stress caused by environmental change, the residual stress in a chip, and the stress generated by packaging and installation are only reflected on the deformation of the substrate 11 and cannot be transmitted to the left sensing electrode 21 and the right sensing electrode 23, the influence of a series of interference factors on the sensing electrode structure of the accelerometer is reduced, and the anti-interference capability of the accelerometer is improved.

the traditional movable sensitive structure of the flat plate type MEMS accelerometer is generally a differential structure formed by a solid structure at one side and an open hollow structure at one side, but the structure is only a single-layer open hollow structure, has lower rigidity and weaker overload resistance, and can be realized by multiple processes when the differential structure with the hollow one side and the solid one side is formed, so the process is more complicated; the two same layers of wafers with the open hollow structures are firmly bonded together through silicon-silicon bonding to form a closed hollow structure, a supporting silicon column 33 is formed inside the closed hollow structure, the rigidity of the movable sensitive structure can be further enhanced through the supporting silicon column 33, the structure can be finally subjected to photoetching and etching once to form a final movable sensitive structure, the process is simple, and the rigidity of the movable sensitive structure is greatly improved due to the fact that the movable sensitive structure is a double-layer reinforced structure, and the overload resistance of the sensor is enhanced.

the foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner; those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.