CN102495234B - Capacitive type micro-acceleration sensor with double-sided symmetrical elastic beam structure and manufacturing method - Google Patents
Capacitive type micro-acceleration sensor with double-sided symmetrical elastic beam structure and manufacturing method Download PDFInfo
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Abstract
The invention relates to a capacitive type micro-acceleration sensor with a double-sided symmetrical elastic beam structure and a manufacturing method. The capacitive type micro-acceleration sensor is characterized in that: (1) an SOI silicon wafer of a double-device layer is a substrate with an elastic beam-mass block structure; (2) a fixed upper electrode and a fixed lower electrode are respectively located on the upper and lower sides of the mass block; (3) the elastic beam is a straight beam of which one end is connected with the mass block, and the other end is connected with a support frame; (4) overload protection salient points are formed on the upper and lower surfaces of the mass block; (5) damping regulation grooves are formed on the upper and lower surfaces of the mass block; and (6) an electrode leading through hole of the mass block is located above the support frame. By adopting the wet etching self-stop technology, the elastic beam-mass block structure which is the most important in the acceleration sensor is processed and formed once in the wet etching; and the bonding of three layers of silicon wafers is realized by a silicon-silicon direct bonding method, and the electrode leading through hole of the mass block is formed on the fixed upper electrode through infrared aligned photoetching. According to the invention, the cross-axis sensitivity is reduced while the device sensitivity is improved.
Description
Technical Field
The invention relates to a capacitive micro acceleration sensor with a double-sided symmetrical elastic beam structure and a manufacturing method thereof, in particular to a capacitive micro acceleration sensor with a double-sided symmetrical elastic beam structure based on a double-device-layer SOI (silicon on insulator) silicon chip and a manufacturing method thereof. Belongs to the field of microelectronic mechanical systems.
Background
The micro acceleration sensor is an important inertial sensor, and converts a physical signal of external acceleration into an electric signal convenient for measurement. The types of the silicon micro acceleration sensor are more, and are divided into an angular vibration type and a linear vibration type according to the motion mode of the detection mass; the device is divided into a torsional pendulum type and a cantilever beam type according to a detection mass supporting mode; the detection method is divided into a capacitance type, a resistance type and a tunnel current type according to a signal detection mode; the control method is divided into open loop and closed loop.
A capacitive acceleration sensor is a sensor that converts a measured acceleration signal into a change in the capacitance of a capacitor. The way to achieve this function is usually both of the variable gap type and the variable area type. When the mass block is acted by acceleration to produce displacement, the gap or relative area of two differential capacitors formed from movable electrode and fixed electrode is changed, so that the capacitance of two differential capacitors is changed, and said change quantity can be detected by means of peripheral circuit, and the acceleration can be measured. The interface circuit of the open-loop acceleration sensor is open-loop, has no feedback and is easily interfered by the outside. The closed-loop working acceleration sensor adopts a feedback function, applies output voltage to the sensitive movable mass block, and enables the mass block to work near a zero position all the time, thereby improving the linearity and the anti-interference capability and improving the dynamic response characteristic.
The method for manufacturing the capacitive micro acceleration sensor comprises a surface micro machining method and a bulk silicon micro machining method. Bulk silicon micromachining processes are a typical micromachining process. In order to form a complete microstructure, a bonding or bonding technology is often applied on the basis of processing, so that the sensitive quality of a movable electrode is increased, the detection capacitance is increased, and the resolution, the sensitivity and other properties of a sensor are improved. The high-performance acceleration sensor usually adopts a double-sided symmetrical elastic beam-mass block structure, and the manufacturing method is very critical and directly influences various performances of the capacitive acceleration sensor. The existing manufacturing method usually adopts a heterogeneous self-stop method, a concentrated boron doping self-stop method and a double-layer bonding method.
A heterogeneous self-stop method is used, such as a silicon dioxide beam process, which comprises the steps of oxidizing a silicon wafer, patterning a beam on an oxide layer, and then releasing a beam-mass structure supported by a silicon dioxide beam by silicon etching. Since silica is brittle and the thickness of silica obtained by oxidation is generally not more than 3 μm, the acceleration sensor using the silica beam can use only a closed-loop detection circuit and has poor impact resistance.
By adopting the method of self-stopping the concentrated boron doping (H Seidel, H Riedel, R Kolbeck, G Mueck, WKupke, M Koeniger, Capacitive Silicon accumulator with high symmetry designed, Sensors and Actuators A: Physical, Vol.21, pp.312-315), when the double-sided symmetrical elastic beam-mass structure is manufactured, the concentrated boron doping layer plays a role of self-stopping to determine the thickness of the beam and also serves as a mask for KOH corrosion in a lightly doped region. The disadvantage of this method is that the non-uniform doping concentration causes the non-uniform thickness of the elastic beam and the residual stress generated in the boron doping process affects the performance of the acceleration sensor, such as sensitivity and linearity.
A double-layer bonding method is adopted to form a double-sided symmetrical elastic beam-mass block structure (W.S. Henrion, et al, Sensors structure with L-shaped spring legs, U.S. Pat. No.5,652,384). The process can adopt a method of KOH corrosion combined with dry deep etching release. The silicon wafer is first etched from the back side with KOH to the thickness of the remaining beam and then the elastic beam-mass structure is released from the front side with dry etch back. Two such elastic beam-mass blocks are bonded back to obtain a double-sided symmetrical structure. This method is very complicated in process and relatively high in cost.
The invention provides a capacitance type micro acceleration sensor with a double-sided symmetrical elastic beam structure, which belongs to a variable clearance type acceleration sensor and is characterized in that a double-device layer SOI silicon chip is used as a substrate, a wet etching self-stop technology is utilized, the most important elastic beam-mass block structure in the acceleration sensor is formed by one-step processing in wet etching, and the elastic beams on the upper surface and the lower surface of a mass block are double-sided symmetrical and parallel. The method provided by the invention simplifies the manufacturing process of the micro acceleration sensor, improves the yield and consistency of the device, improves the sensitivity of the device, reduces the sensitivity of the crossed shaft, and is a very practical high-precision capacitive micro acceleration sensor.
Disclosure of Invention
The invention aims to provide a capacitive micro acceleration sensor with a double-sided symmetrical elastic beam structure. The micro-acceleration sensor is based on a double-device-layer SOI (100) monocrystalline silicon wafer and comprises a mass block, a capacitance gap, a damping adjusting groove, an overload protection salient point, an elastic beam, a fixed upper electrode, a fixed lower electrode and a mass block electrode leading-out through hole, and is characterized in that:
(1) the double-device layer SOI silicon chip is a substrate with an elastic beam-mass block structure;
(2) the fixed upper electrode and the fixed lower electrode are respectively positioned on the upper side and the lower side of the mass block;
(3) the elastic beam is a straight beam, one end of the elastic beam is connected with the mass block, and the other end of the elastic beam is connected with the support frame;
(4) the overload protection salient points are manufactured on the upper surface and the lower surface of the mass block.
(5) The damping adjusting grooves are formed on the upper surface and the lower surface of the mass block.
(6) The position of the mass block electrode lead-out through hole is above the support frame.
The invention provides a capacitance type micro acceleration sensor structure which is characterized in that elastic beams on the upper surface and the lower surface of a mass block in the micro acceleration sensor are symmetrical and parallel, and can be processed at one time in the anisotropic corrosion process of a double-device-layer SOI (100) monocrystalline silicon wafer, and a double-layer symmetrical elastic beam-mass block structure is formed at the same time. The manufactured capacitive micro-acceleration sensor has high normal symmetry, improves the lateral impact and torsional impact resistance of the sensor, and reduces the cross sensitivity.
The capacitive micro acceleration sensor structure provided by the invention is characterized in that the straight elastic beams at eight corners of the mass block are utilized, and the final mass block can be ensured to be in a rectangular structure without adopting a convex angle compensation structure, so that an expected device structure can be completely reserved and not damaged after anisotropic corrosion is finished, and the structural design is simplified. Each corner of the mass block can be distributed with 1 elastic beam or 2 elastic beams, but not limited to the above.
As shown in fig. 2, in the elastic beam-mass block structure proposed by the present invention, the elastic beams are distributed at four corners of an upper layer and a lower layer of the mass block, and the elastic beams at the upper layer and the elastic beams at corresponding positions of the lower layer are symmetrical and parallel to each other.
As shown in fig. 2a, two adjacent elastic beams on the upper layer of the mass block in the elastic beam-mass block structure are respectively arranged in a T shape with the mass block, two adjacent elastic beams on the lower layer of the mass block are also respectively arranged in a T shape with the mass block, and four elastic beams are respectively arranged on the upper layer and the lower layer of the mass block.
Secondly, as shown in fig. 2b, the elastic beam-mass block structures are arranged in an H shape, and the upper layer and the lower layer of the mass block are respectively provided with four elastic beams.
Thirdly, as shown in fig. 2c, the elastic beam-mass block structures are arranged in a well shape, and eight elastic beams are respectively arranged on the upper layer and the lower layer of the mass block.
The invention also provides a manufacturing method of the capacitance type micro acceleration sensor with the double-sided symmetrical elastic beam structure, which is characterized in that an SOI buried layer silicon dioxide layer is used as an automatic stop layer for releasing the elastic beam structure, and the manufacturing method of the beam structure with the accurately controllable thickness is provided.
The second characteristic of the manufacturing method of the invention is to provide a method for realizing bonding of three layers of silicon wafers, which greatly balances the thermal stress generated by high-temperature bonding on the elastic beam, not only simplifies the process, but also realizes that the gap between the fixed upper electrode or the fixed lower electrode and the mass block can be smaller than 3 mu m, so that the manufactured capacitive micro acceleration sensor has higher sensitivity.
The third characteristic of the manufacturing method of the invention is to provide two manufacturing methods of the damping adjusting groove, one adopts two-step photoetching method, and the other forms the V-shaped damping adjusting groove by designing the width of the damping groove and utilizing anisotropic corrosion to stop automatically.
The manufacturing method is characterized in that the pattern of the middle electrode lead hole is subjected to infrared photoetching alignment after the three layers of bonding are finished, and the complex process of bonding pre-alignment is omitted.
The process steps of the manufacture are simply described as follows:
due to the tiny structure (micron order) in the design and the application to the anisotropic etching of silicon, the <110> crystal orientation must be strictly aligned in lithography to ensure the consistent cross-sectional shape of the beam and the rectangular mass.
1. And (3) manufacturing an elastic beam-mass block structure:
(1) manufacturing a capacitance gap smaller than 3 mu m on the upper surface and the lower surface of an oxidized (100) double-polished double-device-layer SOI silicon chip by using an anisotropic etching method;
(2) removing the oxide layer in the rest area, performing secondary oxidation to form silicon oxide, performing double-sided lithography, and manufacturing overload protection bumps (not more than 1 μm) on the upper and lower surfaces of the mass block by an anisotropic etching method;
(3) removing the oxide layer of the rest area, oxidizing to form silicon oxide, performing double-sided lithography, and etching to obtain double-sided symmetrical elastic beam-mass block patterns on the upper and lower surfaces of the silicon wafer by anisotropic etching method, wherein the etching stop layer is a buried oxide layer of SOI and forms a damping adjustment groove;
(4) removing the oxide layer in the remaining area, and covering the upper surface, two side surfaces and the upper and lower surfaces of the mass block of the elastic beam by using silicon oxide through thermal oxidation;
(5) carrying out double-sided photoetching on the silicon wafer again to manufacture a window for carrying out anisotropic etching;
(6) and etching the silicon wafer by using an anisotropic etching method until the double-sided symmetrical elastic beam-mass block structure is formed. When the elastic beam structure is etched, the buried silicon oxide layer of the SOI serves as an etching stop layer, and the automatic stop of the etching beam process is realized.
(7) And removing the oxide layer for corrosion masking in the remaining area to obtain the elastic beam-mass block structure.
2. And the fixed upper electrode and the fixed lower electrode are directly used for manufacturing a silicon dioxide insulating layer through thermal oxidation of a double-polished silicon wafer.
3. The bonding of the layers on the three layers of silicon chips is realized by a silicon-silicon direct bonding method, and the fixed upper electrode, the elastic beam-mass block structure and the fixed lower electrode are bonded together.
4. Manufacturing mass block electrode lead through hole corrosion windows on the upper surface and the lower surface of the bonding sheet through infrared alignment photoetching, and then corroding to form a lead-out through hole of the mass block electrode;
5. the electrode lead-out metal layer of the bonding sheet is formed, and metal (sputtering, evaporation, etc., but not limited thereto) is formed on the front and back surfaces of the bonding sheet (Al, Au, Ni, etc., but not limited thereto).
Two manufacturing methods of damping adjusting groove
(1) Two-step photolithography
The third step of manufacturing the elastic beam-mass block structure is divided into two steps, wherein the first step is to etch the elastic beam-mass block structure by double-sided photoetching, the second step is to etch a damping slot etching window on the surface of the mass block for the second etching, and when the beam structure is etched to the SOI buried layer silicon dioxide, the etching is stopped. Thus, the elastic beam-mass block structure and the damping grooves on the mass block are obtained, and the depth of the damping grooves is equal to that of the secondary corrosion beam structure.
(2) The V-shaped damping adjusting groove is formed by designing the width of the damping groove and utilizing anisotropic corrosion to stop automatically.
The width of the damping adjusting groove is designed, so that the surface of the mass block forms a V-groove structure in the anisotropic corrosion of silicon and stops automatically. The width B of the damping adjusting groove meets the following conditions:h is the thickness of the device layer silicon layer of the SOI silicon wafer.
In summary, the present invention provides a capacitive micro-acceleration sensor with a double-sided symmetrical elastic beam structure and a manufacturing method thereof. The invention also provides a manufacturing method for accurately controlling the thickness of the beam structure, and the silicon oxide of the SOI buried layer is used as the corrosion self-stopping layer, so that the process controllability is greatly improved. The invention provides two methods for manufacturing the damping adjusting groove, and the process is simple and controllable. The invention provides a manufacturing process for realizing a lead hole by infrared alignment after direct three-layer bonding, which omits the complex process flow of bonding pre-alignment, simplifies the process and improves the yield and consistency of devices. The acceleration sensor provided by the invention has stable performance, improves the sensitivity of the device, and reduces the sensitivity of the crossed shaft. And different beam lengths and capacitance gaps can be designed according to requirements, the sensitivity of the sensor is changed, and the flexibility is higher.
Drawings
FIG. 1 is a schematic view of a capacitive micro-acceleration sensor with a double-sided symmetrical elastic beam structure according to the present invention
Fig. 2 is a schematic view of the structure of the elastic beam-mass block according to the present invention.
In fig. 2a, two adjacent elastic beams at the upper layer and the lower layer of the mass block are respectively arranged in a T shape with the mass block, and four elastic beams are respectively arranged at the upper layer and the lower layer of the mass block.
FIG. 2b shows the arrangement of the elastic beam-mass block structure in H-shape, and the upper and lower layers of the mass block are four elastic beams.
FIG. 2c shows the arrangement of the elastic beam-mass block structure in a well shape, and eight elastic beams are respectively arranged on the upper layer and the lower layer of the mass block.
Fig. 3(a) -3 (j) are schematic diagrams of the process flow of the capacitive micro acceleration sensor with a double-sided symmetrical elastic beam structure according to the present invention. Wherein, (a) the top silicon and the buried layer silicon dioxide of the double-device layer SOI silicon wafer; (b) fabricating a capacitor gap on the substrate of (a); (c) manufacturing an overload protection salient point; (d) forming a V-shaped damping adjusting groove; (e) SO for thermal oxidation2Covering the surfaces of the elastic beam and the mass block; (f) opening a window for anisotropic etching; (g) the elastic beam-mass block structure of the middle layer; (h) bonding; (i) forming a lead-out through hole of the mass block electrode; (j) and leading out the metal layer.
Fig. 4(a) -4 (d) are schematic process flow diagrams of the two-step photolithography method for manufacturing the damping adjustment groove. Wherein, (a) a capacitor gap is manufactured; (b) manufacturing an over-protection salient point; (c) manufacturing an elastic beam-mass block graph structure; (d) the damping adjustment groove is manufactured by a photoetching method.
The figures in the drawings represent the meanings:
1. the method comprises the steps of fixing an upper electrode silicon wafer 2, a double-device-layer SOI silicon wafer 3, a fixed lower electrode silicon wafer 4, a mass block 5, an overload protection bump 6, a mass block electrode lead-out metal layer 7, a damping adjusting groove 8, an elastic beam 9, a mass block electrode lead through hole 10, top layer silicon 11 of the double-device-layer SOI silicon wafer, buried layer silicon dioxide 12 of the double-device-layer SOI silicon wafer, a capacitor gap 13, a fixed upper electrode and mass block electrode, a fixed lower electrode and mass block electrode insulating layer silicon dioxide 14, a mass block electrode lead through hole corrosion window 15, a fixed upper electrode lead-out metal layer 16, a fixed lower electrode lead-out metal layer 17, an anisotropic corrosion release window 18
Detailed Description
The following description of the method for manufacturing a capacitive micro acceleration sensor with a double-sided symmetrical elastic beam structure is provided to further illustrate the substantial features and significant progress of the present invention, but the present invention is by no means limited to the embodiments.
Example 1
1. And (3) manufacturing an elastic beam-mass block structure:
(1) manufacturing a capacitor gap 12 on the upper surface and the lower surface of the oxidized double-polished double-device-layer SOI silicon chip by using an anisotropic etching method, wherein the etching depth is 1 mu m (figure 3 b);
(2) removing the oxide layer in the remaining region, performing secondary oxidation to form silicon oxide, performing double-sided lithography, and fabricating overload protection bumps 5 (1 μm high) on the upper and lower surfaces of the mass block by anisotropic etching, as shown in FIG. 3 c;
(3) removing the oxide layer in the remaining region, oxidizing to form silicon oxide, performing double-sided lithography, and etching a double-sided symmetrical elastic beam-mass block structure pattern on the upper and lower surfaces of the silicon wafer by using an anisotropic etching method, wherein the etching stop layer is a buried oxide layer of the SOI and forms a damping adjustment groove 7, as shown in FIG. 3 d; width of damping adjustment grooveH is the thickness of the device layer silicon layer of the SOI silicon wafer.
(4) Removing the oxide layer in the remaining region, and covering the upper surface, two side surfaces and the upper and lower surfaces of the mass block with silicon oxide by thermal oxidation, as shown in fig. 3 e;
(5) performing double-sided lithography on the silicon wafer again, and opening a window 17 for anisotropic etching, as shown in fig. 3 f;
(6) and etching the silicon wafer by using an anisotropic etching method until the elastic beam 8 and the mass block 4 are formed. When the elastic beam structure is etched, the buried silicon oxide layer of the SOI serves as an etching stop layer, and the automatic stop of the etching beam process is realized. And (3) performing wet anisotropic etching to obtain the elastic beam 8 and the mass block 4 at the same time, wherein the etching depth is determined by the thickness of the silicon wafer.
(7) The remaining area of the oxide layer for etch masking is removed resulting in a spring beam-mass structure for the middle layer, as shown in fig. 3 g.
2. The silicon wafer 1 with the fixed upper electrode and the silicon wafer 3 with the fixed lower electrode are directly used for manufacturing a silicon dioxide insulating layer through thermal oxidation of a double-polished silicon wafer.
3. The silicon wafer 1 with the fixed upper electrode, the silicon wafer 2 with the double device layers SOI and the silicon wafer 3 with the fixed lower electrode are bonded together by bonding, as shown in fig. 3 h.
4. And manufacturing mass block electrode lead through hole corrosion windows on the upper surface and the lower surface of the bonding sheet through infrared alignment photoetching, and then corroding to form a lead-out through hole of the mass block electrode, as shown in figure 3 i.
5. And (3) manufacturing an electrode lead-out metal layer of the bonding sheet, and manufacturing Au metal layers on the front side and the back side of the bonding sheet, as shown in figure 3 j.
Example 2
The method for manufacturing the damping adjustment groove in the embodiment 1 comprises the following steps: the V-shaped damping adjusting groove is formed by designing the width of the damping groove and utilizing anisotropic corrosion to stop automatically. In this embodiment 2, a two-step photolithography method is adopted to fabricate the damping adjustment groove.
(1) Utilizing an anisotropic etching method to manufacture a capacitor gap 12 on the upper surface and the lower surface of the oxidized double-polished double-device-layer SOI silicon chip, wherein the etching depth is 1 μm, as shown in FIG. 4 a;
(2) removing the oxide layer in the remaining region, performing secondary oxidation to form silicon oxide, performing double-sided lithography, and making overload protection bumps (1 μm high) on the upper and lower surfaces of the mass block by anisotropic etching, as shown in FIG. 4 b;
(3) removing the oxide layer in the remaining region, oxidizing to form silicon oxide, performing double-sided lithography, and etching the upper and lower surfaces of the silicon wafer to a certain depth by using an anisotropic etching method to produce an elastic beam-mass block pattern as shown in FIG. 4 c;
(4) and performing double-sided photoetching again, photoetching a damping slot corrosion window on the surface of the mass block, performing secondary corrosion, and stopping corrosion when the beam structure corrodes to the SOI buried layer silicon dioxide. This results in a sprung beam-mass structure and damping tuning grooves in the mass, the damping tuning grooves having a depth equal to the depth of the secondary etched beam structure, as shown in figure 4 d. It must be emphasized that the <110> crystal orientation must be aligned strictly in lithography, and the other steps not involved are the same as in example 1.
Claims (9)
1. A method for manufacturing a capacitive micro acceleration sensor with a double-sided symmetrical elastic beam structure is characterized by comprising the following steps:
firstly, the elastic beam-mass block structure is processed once in wet etching:
(a) manufacturing capacitor gaps on the upper surface and the lower surface of an oxidized double-device-layer SOI (100) silicon chip by using an anisotropic etching method;
(b) removing the oxide layer in the rest area, performing secondary oxidation to form silicon oxide, performing double-sided photoetching, and manufacturing overload protection salient points on the upper surface and the lower surface of the mass block by an anisotropic etching method;
(c) removing the oxide layer of the rest area, oxidizing to form silicon oxide, performing double-sided lithography, and etching to obtain double-sided symmetrical elastic beam-mass block patterns on the upper and lower surfaces of the silicon wafer by using an anisotropic etching method, wherein the etching stop layer is a buried oxide layer of the SOI and forms a damping adjustment groove;
(d) removing the oxide layer in the remaining area, and covering the upper surface, two side surfaces and the upper and lower surfaces of the mass block of the elastic beam by using silicon oxide through thermal oxidation;
(e) carrying out double-sided photoetching on the silicon wafer again to manufacture a window for carrying out anisotropic etching;
(f) etching the silicon wafer by using an anisotropic etching method until the formation of the double-sided symmetrical elastic beam-mass block structure, wherein when the elastic beam structure is etched, the buried oxide layer of the SOI serves as an etching stop layer, so that the automatic stop of the etching beam process is realized;
(g) removing the oxide layer for corrosion masking in the remaining area to obtain an elastic beam-mass block structure;
secondly, manufacturing a silicon dioxide insulating layer by directly carrying out thermal oxidation on the fixed upper electrode and the fixed lower electrode through a double-polished silicon wafer;
bonding three layers of silicon chips by a direct silicon-silicon bonding method, and bonding the fixed upper electrode, the elastic beam-mass block structure and the fixed lower electrode together;
fourthly, manufacturing through hole corrosion windows of the mass block electrode lead on the upper surface and the lower surface of the bonding sheet through infrared alignment photoetching, and then corroding to form a lead-out through hole of the mass block electrode;
manufacturing an electrode lead-out metal layer of the bonding sheet, and manufacturing metal layers on the front side and the back side of the bonding sheet;
wherein, there are two manufacturing methods for A and B damping adjustment grooves
(1) Two-step photolithography
The method comprises the following steps that (c) in the manufacturing of the elastic beam-mass block structure, the first step is carried out by two-sided photoetching to enable the elastic beam-mass block structure to be corroded firstly, the second step is carried out by etching a damping groove corrosion window on the surface of the mass block for the second corrosion, when the beam structure is corroded to an SOI buried layer oxide layer, the corrosion is stopped, and the depth of the prepared damping adjusting groove is equal to that of the second corrosion beam structure;
(2) the width of the damping adjusting groove is designed, and the V-shaped damping adjusting groove is formed by utilizing anisotropic corrosion self-stop;
the width of the damping adjusting groove is designed, so that the surface of the mass block forms a V-shaped groove structure in the anisotropic corrosion of silicon and stops automatically, and the width of the damping adjusting grooveH is the thickness of a device layer silicon layer of the SOI silicon wafer;
B. the photolithography involved in the above steps must be strictly aligned to the <110> crystal orientation;
the capacitive micro-acceleration sensor manufactured according to the steps is based on a double-device-layer SOI silicon chip and comprises a mass block, a capacitance gap, a damping adjusting groove, an overload protection salient point, an elastic beam, a fixed upper electrode, a fixed lower electrode and a mass block electrode leading-out through hole; wherein,
(1) the double-device layer SOI silicon chip is a substrate with an elastic beam-mass block structure;
(2) the fixed upper electrode and the fixed lower electrode are respectively positioned on the upper side and the lower side of the mass block;
(3) the elastic beam is a straight beam, one end of the elastic beam is connected with the mass block, and the other end of the elastic beam is connected with the support frame;
(4) the overload protection salient points are manufactured on the upper surface and the lower surface of the mass block;
(5) the damping adjusting grooves are formed on the upper surface and the lower surface of the mass block;
(6) the position of the mass block electrode lead-out through hole is above the support frame.
2. The method of claim 1, wherein the upper and lower surfaces of the dual device layer SOI wafer are formed with a capacitive gap of less than 3 μm.
3. The method of claim 1 wherein the height of the formed overload protection bump is no more than 1 μm.
4. The method of claim 1, wherein the metal layer is formed by sputtering or evaporation, and the metal layer is Al, Au or Ni.
5. The method of claim 1, wherein the spring beam-mass structure of the sensor comprises spring beams disposed at four corners of an upper layer and a lower layer of the mass, the spring beams of the upper layer being symmetrical and parallel to the spring beams of the lower layer.
6. The method of claim 1 or 5, wherein two adjacent beams on the upper layer of the mass block are arranged in a T-shape with respect to the mass block, two adjacent beams on the lower layer of the mass block are arranged in a T-shape with respect to the mass block, and four beams on the upper layer and the lower layer of the mass block are arranged in a T-shape with respect to the mass block.
7. The method of claim 1 or 5, wherein the spring beam-mass structure of the sensor is arranged in an H-shape with four spring beams in the upper and lower layers of the mass.
8. The method of claim 1 or 5, wherein the sensor has a spring beam-mass structure arranged in an H-shape with eight spring beams in the upper and lower layers of the mass.
9. The method of claim 1 or 5, wherein the spring beams of the sensor, without the use of a convex compensation structure, provide a rectangular final mass with a high degree of normal symmetry.
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| CN103675345B (en) * | 2012-09-21 | 2017-12-01 | 中国科学院地质与地球物理研究所 | A kind of accelerometer and its manufacturing process |
| CN103675344B (en) * | 2012-09-21 | 2017-12-22 | 中国科学院地质与地球物理研究所 | A kind of accelerometer and its manufacturing process |
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| CN107045073B (en) * | 2017-02-07 | 2019-07-09 | 中国科学院上海微系统与信息技术研究所 | Single silicon-chip double-sided symmetrical folds girder construction micro-acceleration sensor and preparation method thereof |
| CN112433067A (en) * | 2020-11-16 | 2021-03-02 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Low-cross-axis crosstalk sensitive structure and manufacturing method thereof |
| CN112816737A (en) * | 2020-12-29 | 2021-05-18 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Accelerometer based on hemispherical FP (Fabry-Perot) cavity on-chip integrated optical machine and manufacturing method |
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