MEMS pressure sensor and preparation method thereof

Abstract

The invention belongs to the technical field of micro electro mechanical systems (MEMS), and discloses an MEMS pressure sensor and a preparation method thereof.The MEMS pressure sensor comprises a micro electro mechanical chip, a fixing cover is installed on the outer wall of the micro electro mechanical chip in a sliding mode, a plurality of pins are fixedly arranged at the tops of the two sides of the micro electro mechanical chip respectively, and the pins are connected with the fixing cover in a sliding mode. A plurality of mounting grooves are formed in the outer walls of the two sides of the fixed cover correspondingly, and the same guide mechanisms are arranged on the inner walls of the mounting grooves correspondingly; through the arrangement of the guide mechanism, each pin is surrounded by two guide plates, so that each pin can be accurately positioned and separated, the problem of dislocation in the mounting process is effectively prevented, additional stability and accuracy are provided, the guide function of the guide plates is provided, and the production efficiency is improved. Therefore, the chip can be smoothly and correctly butted to the preset position on the mainboard, the installation accuracy and reliability are greatly improved, and the connection stability of the pins and the mainboard is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-electromechanical systems (MEMS), and in particular is a MEMS pressure sensor and a preparation method thereof. Background Art

[0002] MEMS technology is a new multidisciplinary cross-technology that has developed rapidly in recent years. It is based on micron / nanotechnology and is a cutting-edge technology in the 21st century. In China, MEMS technology is referred to as micro-electromechanical technology.

[0003] It uses micro-manufacturing technology to integrate sensor actuators, electronic components and mechanical parts on an ordinary silicon wafer substrate to form a micro system with specific functions. This technology does not simply miniaturize mechanical and electronic functions onto the chip, but combines large-scale integrated circuit technology with modern material manufacturing technology to obtain new electromechanical properties. The connection method between the pins on the MEMS pressure sensor and the motherboard does usually involve welding, but this method is not the only option. It also covers a variety of methods such as plug-in connection and snap-on connection. These diverse connection methods are designed to adapt to different application scenarios and installation requirements. However, the pins of MEMS pressure sensors are usually exposed, and because they are very small and thin, they are quite fragile. When installing, you must be extra careful to avoid offset between multiple pins due to uneven force. This offset may cause the pins to bend, which in turn causes errors in connection, ultimately causing the sensor to malfunction or be damaged. Therefore, it needs to be improved and optimized. Summary of the invention

[0004] In order to solve the problem of fragility and vulnerability of the connection between the pins of a MEMS pressure sensor and a mainboard raised in the above background technology, the present invention provides a MEMS pressure sensor and a method for preparing the same.

[0005] To achieve the above object, the present invention provides the following technical solution: a MEMS pressure sensor, comprising a micro-electromechanical chip, a fixed cover is slidably mounted on the outer wall of the micro-electromechanical chip, a plurality of pins are fixedly mounted on the tops of both sides of the micro-electromechanical chip, a plurality of mounting grooves are respectively opened on the outer walls of both sides of the fixed cover, and the inner walls of the plurality of mounting grooves are respectively provided with the same guiding mechanism; The guide mechanism comprises two guide plates hingedly mounted on the inner wall of the mounting groove, the two guide plates are elastically connected to the side of the mounting groove close to each other through spring 2, and the two guide plates are slidably connected to the corresponding pins.

[0006] Preferably, a fixing plate is fixedly mounted on the front and back of the micro-electromechanical chip, a plurality of cylinders are fixedly mounted on the top inner wall of the fixing cover, a plurality of clamping blocks are fixedly mounted on the bottoms of the cylinders, and a plurality of buckle mechanisms are arranged on the top of the fixing plate; The snap mechanism includes two fixed blocks fixedly installed on the top of the fixed plate, and two clamping blocks are hingedly installed on one side of the two fixed blocks close to each other. The two clamping blocks are hinged, and the two clamping blocks are elastically connected to the top of the fixed plate respectively through two springs, and the two clamping blocks are both clamped with the corresponding clamping blocks.

[0007] Preferably, the outer shape of the mounting groove is designed to be a trapezoidal structure, and the second spring is arranged at the two waists of the bottom of the mounting groove.

[0008] Preferably, the pin adopts an S-shaped design, the cross-sectional area of ​​the pin at the turning point is wider than that at the two ends, and a crescent groove is provided on the outer wall of the turning point of the pin, and the crescent groove runs through one side of the pin to the other side.

[0009] Preferably, the bottoms of the two guide plates on the sides close to each other are respectively inclined, and the inclination angles of the two guide plates are symmetrically distributed.

[0010] Preferably, a hollow column is fixedly mounted on the top of the fixed cover, and the hollow column is slidably connected to the micro-electromechanical chip.

[0011] Preferably, the two fixing plates are designed to be right-angled triangles, and the snap-fit ​​mechanism and the micro-electromechanical chip are both fixedly connected to the right-angled sides of the fixing plates.

[0012] Preferably, a plurality of slide grooves are respectively provided on the front and back sides of the micro-electromechanical system chip, and the plurality of slide grooves are semicircular, and the diameter of the semicircle is equal to the diameter of the cylinder.

[0013] Preferably, a plurality of the buckle mechanisms are arranged linearly, and the distance between two adjacent buckle mechanisms is the same.

[0014] A method for preparing a MEMS pressure sensor, the specific steps of the preparation method comprising: S1, preparing piezoresistors and metal interconnection leads: selecting a silicon wafer as a substrate, forming a thin film on the silicon wafer by a silicon nitride thin film thermal deposition process, forming a pattern on the thin film by using a photolithography technique, and preparing piezoresistors and metal interconnection leads by a metal ion implantation process; S2, preparing a pressure sensitive film: performing anisotropic wet etching on the back of the silicon wafer, and controlling the thickness of the pressure sensitive film by adjusting the etching rate and time; S3, preparation of chip support structure; using glass material for bonding as the chip support structure; S4, packaging and testing: packaging the prepared MEMS pressure sensor chip and performing performance testing on the packaged sensor.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention ensures that the pins can be accurately positioned at the predetermined positions during the installation process by setting up a guiding mechanism. The traditional installation method is often prone to misalignment due to slight differences between the pins or improper operation. The present invention not only provides a clear guide for the pins by setting up a guide plate, but also the guiding mechanism not only prevents the misalignment problem during the installation process, but also significantly improves the stability and accuracy of the installation. While the pins are tightly surrounded by the guide plate, the elastic action of the second spring enables the pins to obtain uniform force distribution during the insertion process, avoiding bending or damage of the pins due to uneven force.

[0016] The present invention provides an S-shaped pin to increase the strength and toughness of the turning point, so that the pin can better withstand the stress and tension caused by bending. During the operation of the device, the pin needs to withstand forces and vibrations from all directions, and the S-shaped design and the wide cross-sectional area of ​​the turning point can effectively disperse and relieve the force, thereby extending the service life of the pin. In addition, a crescent groove is provided on the outer wall of the turning point of the pin to further enhance the strength and toughness of the turning point. The crescent groove runs through one side of the pin to the other side to form a continuous channel, so that the pin can undergo a slight elastic deformation when subjected to external force, thereby absorbing and dispersing stress and avoiding damage caused by stress concentration. The design of the crescent groove also optimizes the heat dissipation performance of the pin. When the device is working, the pin will generate a certain amount of heat. The presence of the crescent groove increases the heat dissipation area of ​​the pin surface, improves the heat dissipation efficiency, and ensures the stable operation of the device.

[0017] The present invention adopts a snap mechanism composed of a card block, a clamping block and a spring. As the fixed cover is pressed down, the card block gradually approaches and squeezes the clamping block. The hinge design of the clamping block is used to achieve adaptive adjustment. When the card block reaches the lowest point, the rebound force of the spring drives the clamping block to move toward the middle and clamps the card block, thereby achieving a firm fixation between the micro-electromechanical chip and the fixed cover.

[0018] The present invention ensures the uniformity of the sensor when subjected to force through symmetrically distributed tilt angles. The inclined guide plate also provides a certain degree of adaptability for the sensor, so that when the fixed cover moves downward, the guidance and isolation of the guide plate can not only limit the pins but also prevent the pins from shifting. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the explosion structure of the present invention; Figure 3 It is a schematic diagram of the guiding mechanism structure of the present invention; Figure 4 For the present invention Figure 3 A is a schematic diagram of the enlarged structure of the middle part; Figure 5 This is a schematic diagram of the structure of the fixed cover of the present invention; Figure 6 This is a schematic diagram of the fixing plate structure of the present invention; Figure 7 It is a schematic diagram of the front cross-sectional structure of the fixed cover of the present invention; Figure 8 For the present invention Figure 7 A schematic diagram of the enlarged structure of B; Fig. 9 It is a schematic diagram of the pin structure of the present invention.

[0020] In the figure: 1. MEMS chip; 101. fixing plate; 1011. fixing block; 1012. clamping block; 1013. spring 1; 102. slide groove; 2. fixing cover; 201. cylinder; 2011. clamping block; 202. mounting groove; 2021. guide plate; 2022. spring 2; 203. hollow column; 3. pin. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0022] like Figures 1 to 9 As shown, the present invention provides a MEMS pressure sensor, including a micro-electromechanical chip 1, a fixed cover 2 is slidably mounted on the outer wall of the micro-electromechanical chip 1, a plurality of pins 3 are fixedly mounted on the tops of both sides of the micro-electromechanical chip 1, a plurality of mounting grooves 202 are respectively opened on the outer walls of both sides of the fixed cover 2, and the inner walls of the plurality of mounting grooves 202 are respectively provided with the same guiding mechanism; The guiding mechanism includes two guiding plates 2021 hingedly mounted on the inner wall of the mounting groove 202. The two guiding plates 2021 are elastically connected to the side of the mounting groove 202 close to each other through spring 2022. The two guiding plates 2021 are both slidably connected to the corresponding pins 3. The outer shape of the mounting groove 202 is designed to be a trapezoidal structure, and the spring 2022 is arranged at the two waists of the bottom of the mounting groove 202. The pin 3 adopts an S-shaped design. The cross-sectional area of ​​the pin 3 at the turning point is wider than that at the two ends. A crescent groove is provided on the outer wall of the turning point of the pin 3, and the crescent groove runs from one side of the pin 3 to the other side. The bottoms of the two guiding plates 2021 are inclined on the side close to each other, and the inclination angles of the two guiding plates 2021 are symmetrically distributed. A hollow column 203 is fixedly mounted on the top of the fixed cover 2, and the hollow column 203 is slidably connected to the micro-electromechanical chip 1.

[0023] By setting a guide plate 2021, which is elastically connected to the two waist positions at the bottom of the installation groove 202 through a spring 2022, when the pin 3 is inserted into the installation groove 202, it is ensured that the pin 3 is stably guided to the correct position. By setting an S-shaped pin 3, the strength and toughness of the turning part are increased, so that the pin 3 can better withstand the stress and tension caused by bending. During the operation of the device, the pin 3 needs to withstand forces and vibrations from all aspects, and the S-shaped design and the wide cross-sectional area of ​​the turning part can effectively disperse and alleviate these forces, thereby extending the service life of the pin 3. In addition, by opening a crescent groove on the outer wall of the turning part of the pin 3, the strength and toughness of the turning part are further enhanced. The crescent groove runs through one side of the pin 3 to the other side, forming a continuous channel, so that the pin 3 can be subjected to external force. The crescent groove design also optimizes the heat dissipation performance of the pin 3. When the device is working, the pin 3 will generate a certain amount of heat. The existence of the crescent groove increases the heat dissipation area on the surface of the pin 3, and improves the heat dissipation efficiency, thereby ensuring the stable operation of the device. The symmetrically distributed inclination angles ensure the uniformity of the sensor when it is subjected to force. The inclined guide plate 2021 also provides a certain degree of adaptability for the sensor, so that when the fixed cover 2 moves downward, the guide plate 2021 is guided and isolated, which can not only limit the pin 3, but also prevent the pin 3 from shifting. The sliding connection design allows the micro-electromechanical chip 1 to move to a certain extent inside the hollow column 203, and the sliding path can be limited. Embodiment 2

[0024] like Figures 2 to 8As shown, a fixing plate 101 is fixedly installed on the front and back of the micro-electromechanical chip 1, a plurality of cylinders 201 are fixedly installed on the top inner wall of the fixing cover 2, a plurality of clamping blocks 2011 are fixedly installed on the bottom of the plurality of cylinders 201, and a plurality of buckle mechanisms are arranged on the top of the fixing plate 101; The snap mechanism includes two fixed blocks 1011 fixedly installed on the top of the fixed plate 101, and two clamping blocks 1012 are hingedly installed on one side of the two fixed blocks 1011 close to each other. The two clamping blocks 1012 are hinged, and the two clamping blocks 1012 are elastically connected to the top of the fixed plate 101 respectively through two springs 1013, and the two clamping blocks 1012 are clamped with the corresponding clamping blocks 2011. The two fixed plates 101 are designed as a right-angled triangle, and the snap mechanism and the micro-electromechanical chip 1 are fixedly connected to the right-angled sides of the fixed plate 101. A plurality of slide grooves 102 are respectively provided on the front and back sides of the micro-electromechanical chip 1, and the plurality of slide grooves 102 are semicircular, and the diameter value of the semicircle is equal to the diameter value of the cylinder 201. The plurality of snap mechanisms are arranged linearly, and the distance between two adjacent snap mechanisms is the same.

[0025] By fixing the fixing plates 101 on the front and back of the micro-electromechanical chip 1, respectively, a more uniform supporting force is provided, which effectively prevents deformation or displacement of the buckle mechanism during use. By setting the buckle mechanism, when the fixed cover 2 moves downward, the cylinder 201 and the clamping block 2011 thereon will interact with the buckle mechanism; through the hinged design of the clamping block 1012 and the elastic connection of the spring 1013, the clamping block 2011 can be smoothly clamped by the clamping block 1012, thereby realizing a firm connection between the fixed cover 2 and the fixing plate 101. By setting the fixing plate 101 in the shape of a right triangle, the stability of the buckle mechanism is improved, and it can effectively resist external forces, thereby ensuring the stable operation of the device in complex environments. Secondly, The design of the right-angled edges makes the fixation of the snap mechanism and the micro-electromechanical chip 1 more secure, reducing the risk of loosening due to vibration or impact; by designing that the diameter value of the semicircle is equal to the diameter value of the cylinder 201, the cylinder 201 can be embedded in the slide groove 102, ensuring the stability of the structure and achieving precise positioning, and the semi-circular slide groove 102 also helps to reduce the friction resistance during sliding, making the movement of the cylinder 201 in the slide groove 102 smoother; through the linear arrangement and equidistant snap mechanism design, the micro-electromechanical chip 1 and the fixing cover 2 can be assembled more conveniently when connected, and the uniform distribution can ensure that the force on the micro-electromechanical chip 1 and the fixing cover 2 in all directions is more balanced, thereby improving its overall stability.

[0026] A method for preparing a MEMS pressure sensor, the specific steps of the preparation method comprising: S1, preparing piezoresistors and metal interconnection leads: selecting a silicon wafer as a substrate, forming a thin film on the silicon wafer by a silicon nitride thin film thermal deposition process, forming a pattern on the thin film by using a photolithography technique, and preparing piezoresistors and metal interconnection leads by a metal ion implantation process; S2, preparing a pressure sensitive film: performing anisotropic wet etching on the back of the silicon wafer, and controlling the thickness of the pressure sensitive film by adjusting the etching rate and time; S3, preparation of chip support structure: using glass material for bonding as the chip support structure to ensure the stability of the chip; S4, packaging and testing: The prepared MEMS pressure sensor chip is packaged to protect it from interference and damage from the external environment, and the performance of the packaged sensor is tested, including sensitivity, response time, stability and other indicators, to ensure the performance of the sensor in actual applications.

[0027] The working principle and use process of the present invention: The MEMS chip 1 is accurately placed at the predetermined position on the mainboard, and the fixing cover 2 is placed above the MEMS chip 1, preparing for the next fixing operation. During the downward movement of the fixing cover 2, each guide plate 2021 on the fixing cover 2 will contact the adjacent pin 3, ensuring that each pin 3 can be correctly positioned and separated to prevent misalignment during the installation process. Since each pin 3 is surrounded by two guide plates 2021, additional stability and accuracy are provided. As the fixing cover 2 continues to be pressed down, several cylinders 201 on the fixing cover 2 will also move together. These cylinders 201 are equipped with card blocks 2011, which move with the movement of the cylinders 201, and the card blocks 2011 gradually approach the two clamping blocks 1 on the fixing plate 101. 012. When the card block 2011 contacts the two clamping blocks 1012, due to the hinged design of the clamping blocks 1012, the card block 2011 will squeeze the two clamping blocks 1012 outward. As the fixed cover 2 is further pressed down, the card block 2011 finally moves to the lowest point of its stroke. At this time, the card block 2011 has been completely inserted between the two clamping blocks 1012. After the card block 2011 reaches the lowest point, the fixed cover 2 is released, and the cylinder 201 and the card block 2011 on the fixed cover 2 are no longer subjected to downward pressure. After the fixed cover 2 is released, the spring 1013 on the fixed plate 101 begins to rebound, and the elastic force drives the two clamping blocks 1012 to move toward the middle, thereby clamping the card block 2011, ensuring the firm fixation between the micro-electromechanical chip 1 and the fixed cover 2.

[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0029] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A MEMS pressure sensor, comprising a micro-electromechanical chip (1), characterized in that: A fixed cover (2) is slidably mounted on the outer wall of the micro-electromechanical chip (1), a plurality of pins (3) are fixedly mounted on the tops of both sides of the micro-electromechanical chip (1), a plurality of mounting grooves (202) are respectively opened on the outer walls of both sides of the fixed cover (2), and the inner walls of the plurality of mounting grooves (202) are respectively provided with the same guiding mechanism; The guide mechanism comprises two guide plates (2021) hingedly mounted on the inner wall of the mounting groove (202), the two guide plates (2021) being elastically connected to the sides of the mounting groove (202) close to each other respectively via spring 2 (2022), and the two guide plates (2021) are both slidably connected to corresponding pins (3); A fixing plate (101) is fixedly mounted on the front and back of the micro-electromechanical chip (1), respectively, and a plurality of snap-fit ​​mechanisms are arranged on the top of the fixing plate (101); The snap mechanism comprises two fixing blocks (1011) fixedly mounted on the top of the fixing plate (101); two clamping blocks (1012) are hingedly mounted on one side of the two fixing blocks (1011) close to each other; the two clamping blocks (1012) are hingedly connected; the two clamping blocks (1012) are elastically connected to the top of the fixing plate (101) respectively via two springs (1013); and the two clamping blocks (1012) are both clamped with corresponding clamping blocks (2011).

2. The MEMS pressure sensor according to claim 1, characterized in that: A plurality of cylinders (201) are fixedly mounted on the inner wall of the top of the fixed cover (2), and a clamping block (2011) is respectively fixedly mounted on the bottom of the plurality of cylinders (201).

3. The MEMS pressure sensor according to claim 1, characterized in that: The outer shape of the installation slot (202) is designed to be a trapezoidal structure, and the second spring (2022) is arranged at the two waists of the bottom of the installation slot (202).

4. The MEMS pressure sensor according to claim 1, characterized in that: The pin (3) adopts an S-shaped design, and the cross-sectional area of ​​the pin (3) at the turning point is wider than that at the two ends. A crescent groove is provided on the outer wall of the turning point of the pin (3), and the crescent groove runs through one side of the pin (3) to the other side.

5. The MEMS pressure sensor according to claim 1, characterized in that: The bottoms of the two guide plates (2021) are respectively inclined on the sides close to each other, and the inclination angles of the two guide plates (2021) are symmetrically distributed.

6. The MEMS pressure sensor according to claim 1, characterized in that: A hollow column (203) is fixedly mounted on the top of the fixed cover (2), and the hollow column (203) is slidably connected to the micro-electromechanical chip (1).

7. The MEMS pressure sensor according to claim 2, characterized in that: The two fixing plates (101) are designed in the shape of a right-angled triangle, and the snap-fit ​​mechanism and the micro-electromechanical chip (1) are both fixedly connected to the right-angled sides of the fixing plates (101).

8. The MEMS pressure sensor according to claim 2, characterized in that: The front and back sides of the micro-electromechanical chip (1) are respectively provided with a plurality of slide grooves (102), the plurality of slide grooves (102) being semicircular in shape, and the diameter of the semicircle is equal to the diameter of the cylinder (201).

9. The MEMS pressure sensor according to claim 2, characterized in that: The plurality of buckle mechanisms are arranged linearly, and the distance between two adjacent buckle mechanisms is the same.

10. A method for preparing a MEMS pressure sensor, applied to the MEMS pressure sensor according to any one of claims 1 to 9, characterized in that: The specific steps of the preparation method include: S1, preparing piezoresistors and metal interconnection leads: selecting a silicon wafer as a substrate, forming a thin film on the silicon wafer by a silicon nitride thin film thermal deposition process, forming a pattern on the thin film by using a photolithography technique, and preparing piezoresistors and metal interconnection leads by a metal ion implantation process; S2, preparing a pressure sensitive film: performing anisotropic wet etching on the back of the silicon wafer, and controlling the thickness of the pressure sensitive film by adjusting the etching rate and time; S3, preparation of chip support structure; bonding using glass material as the chip support structure; S4, packaging and testing: packaging the prepared MEMS pressure sensor chip and performing performance testing on the packaged sensor.

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