A MEMS pressure sensor and a method of manufacturing the same

Abstract

The application belongs to the technical field of micro-electro-mechanical system (MEMS), and discloses a MEMS pressure sensor and a preparation method thereof, which comprises a micro-electro-mechanical chip, a fixed cover is slidably installed on the outer wall of the micro-electro-mechanical chip, a plurality of pins are fixedly arranged on the top of the two sides of the micro-electro-mechanical chip, a plurality of installation grooves are formed on the outer walls of the two sides of the fixed cover, and the same guide mechanism is arranged on the inner walls of the installation grooves. Through the guide mechanism, each pin is surrounded by two guide plates, so that each pin can be accurately positioned and separated, the misalignment problem in the installation process is effectively prevented, additional stability and accuracy are provided, the guide function of the guide plate enables the chip to be smoothly and correctly docked to the predetermined position on the mainboard, the installation accuracy and reliability are greatly improved, and the stability of the pin connection with the mainboard is enhanced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of micro-electro-mechanical system (MEMS), and particularly relates to a MEMS pressure sensor and a preparation method thereof. BACKGROUND

[0002] MEMS technology is a new type of multi-disciplinary technology rapidly developed in recent years, is based on micron / nanometer technology, and is a frontier technology in the 21st century.

[0003] It utilizes microfabrication technology to integrate sensor execution elements, electronic elements and mechanical parts on a common silicon substrate to form a micro system with specific functions.

[0004] The connection mode of the pins on the MEMS pressure sensor and the mainboard usually includes welding, but this mode is not the only choice, and various methods such as plug-in connection and buckle connection are also included. These diversified connection modes are designed to adapt to different application scenarios and installation requirements. However, the pins of the MEMS pressure sensor are usually exposed, and since they are very small and thin, they are quite fragile. Therefore, great care must be taken during installation to avoid the offset between multiple pins due to uneven force, which may cause the pins to bend and result in errors during connection, ultimately leading to the failure of the sensor to work normally or being damaged. Therefore, it is necessary to improve and optimize it. SUMMARY

[0005] To solve the problem of the fragility and vulnerability of the connection mode of the pins of the MEMS pressure sensor and the mainboard in the background art, the application provides a MEMS pressure sensor and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the application provides the following technical scheme: a MEMS pressure sensor, comprising a micro-electro-mechanical chip, a fixed cover is slidably installed on the outer wall of the micro-electro-mechanical chip, a plurality of pins are fixedly arranged on the top of the two sides of the micro-electro-mechanical chip, respectively, a plurality of installation grooves are formed on the outer walls of the two sides of the fixed cover, respectively, and the same guide mechanism is arranged on the inner walls of the plurality of installation grooves.

[0007] The guide mechanism comprises two guide plates hingedly installed on the inner walls of the installation grooves, the two guide plates are elastically connected to each other through springs two on the side close to the installation grooves, respectively, and the two guide plates are slidably connected to the corresponding pins.

[0008] Preferably, a fixing plate is fixedly installed on the front and back of the microelectromechanical chip, a plurality of cylinders are fixedly installed on the top inner wall of the fixing cover, a locking block is fixedly installed at the bottom of the plurality of cylinders, and a plurality of latching mechanisms are provided on the top of the fixing plate.

[0009] The latching mechanism includes two fixing blocks fixedly installed on the top of the fixing plate. Two clamping blocks are hinged to one side of the two fixing blocks that are close to each other. The two clamping blocks are hinged together and elastically connected to the top of the fixing plate by two springs. Both clamping blocks are engaged with corresponding latching blocks.

[0010] Preferably, the mounting groove is designed as a trapezoidal structure, and the second spring is located at the two waist positions at the bottom of the mounting groove.

[0011] Preferably, the pin adopts an S-shaped design, and the cross-sectional area of ​​the bend of the pin is wider than that of the two ends. A crescent groove is formed on the outer wall of the bend of the pin, and the crescent groove runs from one side of the pin to the other side.

[0012] Preferably, the bottoms of the two guide plates on the side that are close to each other are designed with an inclination, and the inclination angles of the two guide plates are symmetrically distributed.

[0013] Preferably, a hollow column is fixedly installed on the top of the fixed cover, and the hollow column is slidably connected to the microelectromechanical chip.

[0014] Preferably, the two fixing plates are designed in a right-angled triangle, and the buckling mechanism and the microelectromechanical chip are both fixedly connected to the right-angled side of the fixing plate.

[0015] Preferably, the microelectromechanical chip has a plurality of grooves on its front and back sides, and the plurality of grooves are semi-circular, with the diameter of the semi-circle being equal to the diameter of the cylinder.

[0016] Preferably, the plurality of the latching mechanisms are arranged linearly, and the distance between two adjacent latching mechanisms is the same.

[0017] A method for fabricating a MEMS pressure sensor, the specific steps of which include:

[0018] S1, Fabrication of pressure resistor and metal interconnect leads: Select a silicon wafer as the substrate, form a thin film on the silicon wafer through silicon nitride thin film thermal deposition process, form a pattern on the thin film using photolithography, and fabricate the pressure resistor and metal interconnect leads through metal ion implantation process.

[0019] S2, Preparation of pressure-sensitive film: Anisotropic wet etching is performed on the back of the silicon wafer, and the thickness of the pressure-sensitive film is controlled by adjusting the etching rate and time;

[0020] S3, chip support architecture preparation; bonding is performed using a glass material as the support architecture of the chip;

[0021] S4, packaging and testing; the prepared MEMS pressure sensor chip is packaged, and performance testing is performed on the packaged sensor.

[0022] Compared with the prior art, the beneficial effects of the present application are as follows:

[0023] The present application sets up a guide mechanism to ensure that the pins can be accurately positioned to the predetermined position during installation. The traditional installation method is prone to mispositioning due to small differences between the pins or improper operation. The present application sets up a guide plate to provide clear guidance for the pins. In addition, the guide mechanism not only prevents mispositioning during installation, but also significantly improves the stability and accuracy of installation. While the pins are tightly surrounded by the guide plate, the elastic action of spring two enables uniform force distribution during insertion, avoiding pin bending or damage due to uneven force.

[0024] The present application sets up an S-shaped pin design to increase the strength and toughness of the turning part, enabling the pin to better withstand stress and tension caused by bending. During the operation of the device, the pin needs to withstand forces and vibrations from all directions. The S-shaped design and wide turning part cross-sectional area can effectively disperse and relieve the force, thereby prolonging the service life of the pin. In addition, the crescent groove on the outer wall of the turning part of the pin further enhances the strength and toughness of the turning part. The crescent groove penetrates from one side of the pin to the other side, forming a continuous channel. When the pin is subjected to external force, it can undergo slight elastic deformation, 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 some heat. The existence 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.

[0025] The present application sets up a clamping mechanism composed of a clamping block, a clamping block and a spring. With the depression of the fixing cover, the clamping block gradually approaches and extrudes the clamping block. The self-adaptive adjustment is realized by the hinged design of the clamping block. When the clamping block reaches the lowest point, the spring drives the clamping block to move to the middle, clamping the clamping block, thereby realizing the firm fixation between the micro-electromechanical chip and the fixing cover.

[0026] The present application ensures the uniformity of the sensor when stressed through the symmetrically distributed tilt angle, and the guiding plate designed in a tilt manner also provides certain self-adaptability for the sensor, so that when the fixing cover moves downward, the guiding and isolation of the guiding plate can not only limit the pins, but also prevent the pins from deviating. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present application;

[0028] Figure 2 It is an explosive structural schematic diagram of the present application;

[0029] Figure 3 It is a guiding mechanism structural schematic diagram of the present application;

[0030] Figure 4 It is an enlarged structural schematic diagram of A in the present application; Figure 3

[0031] Figure 5 It is a fixing cover structural schematic diagram of the present application;

[0032] Figure 6 It is a fixed plate structural schematic diagram of the present application;

[0033] Figure 7 It is a fixing cover front cross-sectional structural schematic diagram of the present application;

[0034] Figure 8 It is an enlarged structural schematic diagram of B in the present application; Figure 7

[0035] Figure 9 It is a pin structural schematic diagram of the present application.

[0036] In the figure: 1, micro-electromechanical chip; 101, fixed plate; 1011, fixed block; 1012, clamping block; 1013, spring one; 102, sliding groove; 2, fixing cover; 201, cylinder; 2011, clamping block; 202, mounting groove; 2021, guiding plate; 2022, spring two; 203, hollow column; 3, pin. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. Embodiment one

[0038] As Figures 1 to 9 ​​As shown, the present application provides a kind of MEMS pressure sensor, including micro-electromechanical chip 1, fixed cover 2 is slidably installed on the outer wall of micro-electromechanical chip 1, the top of the two sides of micro-electromechanical chip 1 is respectively fixedly provided with a plurality of pins 3, a plurality of installation grooves 202 are respectively formed in the outer wall of the two sides of fixed cover 2, and the same guide mechanism is respectively arranged on the inner wall of a plurality of installation grooves 202;

[0039] The guide mechanism includes two guide plates 2021 hingedly installed on the inner wall of installation groove 202, two guide plates 2021 are respectively elastically connected by spring two 2022 on the side close to each other of installation groove 202, two guide plates 2021 are all slidably connected with corresponding pin 3, the shape of installation groove 202 is designed as trapezoidal structure, and spring two 2022 is arranged at the position of the two waists of the bottom of installation groove 202, pin 3 adopts S type design, the cross-sectional area of the turning part of pin 3 is larger than that of both ends, a crescent groove is formed on the outer wall of the turning part of pin 3, the crescent groove penetrates from one side of pin 3 to the other side, the bottom of two guide plates 2021 on the side close to each other is respectively designed as inclined, and the inclined angles of the two guide plates 2021 are symmetrically distributed, hollow column 203 is fixedly installed on the top of fixed cover 2, and hollow column 203 is slidably connected with micro-electromechanical chip 1.

[0040] By setting the guide plate 2021, and then elastically connecting the spring 2022 at the bottom of the two waist positions of the installation slot 202, when the pin 3 is inserted into the installation slot 202, it is ensured that the pin 3 is stably guided to the correct position, by setting the S-shaped design of the pin 3, by increasing the strength and toughness of the turning, the pin 3 can better withstand the stress and tension caused by bending, in the working process of the device, the pin 3 needs to withstand forces and vibrations from all directions, and the S-shaped design and wide turning cross-sectional area can effectively disperse and alleviate these forces, thereby prolonging the service life of the pin 3, in addition, by opening the crescent groove on the outer wall of the turning of the pin 3, the strength and toughness of the turning are further enhanced, the crescent groove penetrates from one side of the pin 3 to the other side, forming a continuous channel, so that the pin 3 can be elastically deformed slightly when subjected to external force, thereby absorbing and dispersing stress, avoiding damage caused by stress concentration, and the design of the crescent groove also optimizes the heat dissipation performance of the pin 3, when the device is working, the pin 3 will generate some heat, the existence of the crescent groove increases the heat dissipation area of the pin 3 surface, improves the heat dissipation efficiency, thereby ensuring the stable work of the device; the uniformity of the sensor when stressed is ensured by the symmetrical distribution of the inclined angle, the inclined guide plate 2021 also provides a certain adaptability for the sensor, so that when the fixed cover 2 moves downward, through the guidance and isolation of the guide plate 2021, not only can the pin 3 be limited, but also can prevent the pin 3 from deviating; through the design of sliding connection, the micro-electromechanical chip 1 can move to a certain extent inside the hollow column 203, and the sliding path can be limited. Example two

[0041] As shown in Figures 2 to 8 The front and back of the micro-electromechanical chip 1 are respectively fixedly installed with the fixed plate 101, the top inner wall of the fixed cover 2 is fixedly installed with a plurality of cylinders 201, the bottoms of the plurality of cylinders 201 are respectively fixedly installed with the clamping block 2011, and the top of the fixed plate 101 is provided with a plurality of buckle mechanisms;

[0042] The buckle mechanism comprises two fixed blocks 1011 fixedly installed on the top of the fixed plate 101, two clamping blocks 1012 hingedly installed on the side close to each other of the two fixed blocks 1011, the two clamping blocks 1012 are hingedly connected, the two clamping blocks 1012 are respectively elastically connected to the top of the fixed plate 101 through two springs 1013, the two clamping blocks 1012 are respectively clamped with the corresponding clamping blocks 2011, the two fixed plates 101 are designed in the shape of a right triangle, the buckle mechanism and the micro-electromechanical chip 1 are fixedly connected to the right angle side of the fixed plate 101, a plurality of sliding grooves 102 are respectively formed on the front and back surfaces of the micro-electromechanical chip 1, the plurality of sliding grooves 102 are semicircular, the diameter of the semicircle is equal to the diameter of the cylinder 201, and the plurality of buckle mechanisms are linearly arranged and the distance between the two adjacent buckle mechanisms is the same.

[0043] By fixedly installing the fixed plate 101 on the front and back surfaces of the micro-electromechanical chip 1, more uniform support force is provided, and deformation or displacement of the buckle mechanism during use is effectively prevented, by arranging the buckle mechanism, when the fixed cover 2 moves downward, the cylinder 201 and the clamping block 2011 on the fixed cover 2 interact with the buckle mechanism, by the hinged design of the clamping block 1012 and the elastic connection of the spring 1013, the clamping block 2011 can be clamped by the clamping block 1012, thereby achieving firm connection between the fixed cover 2 and the fixed plate 101, by arranging the fixed plate 101 in the shape of a right triangle, the stability of the buckle mechanism is improved, which can effectively resist external force, thereby ensuring stable operation of the device in complex environment, secondly, the design of the right angle side makes the fixation of the buckle mechanism and the micro-electromechanical chip 1 more firm, and reduces the risk of loosening caused by vibration or impact, by the design that the diameter of the semicircle is equal to the diameter of the cylinder 201, the cylinder 201 can be embedded in the sliding groove 102, which ensures the stability of the structure and achieves precise positioning, the semicircular sliding groove 102 also helps to reduce the frictional resistance during sliding, so that the movement of the cylinder 201 in the sliding groove 102 is smoother, by the linear arrangement and equal distance of the buckle mechanism, the micro-electromechanical chip 1 and the fixed cover 2 can be more conveniently assembled when connected, uniform distribution can ensure that the micro-electromechanical chip 1 and the fixed cover 2 are more balanced in stress in all directions, thereby improving the overall stability.

[0044] A preparation method of a MEMS pressure sensor, the specific steps of the preparation method comprise:

[0045] S1, preparing a pressure resistor and a metal interconnection lead: selecting a silicon wafer as a substrate, forming a thin film on the silicon wafer through a silicon nitride thin film thermal deposition process, forming a pattern on the thin film by using a photoetching technology, and preparing a pressure resistor and a metal interconnection lead through a metal ion implantation process;

[0046] S2, preparation of pressure sensitive film: anisotropic wet etching is performed on the back of the silicon wafer, and the thickness of the pressure sensitive film is controlled by adjusting the etching rate and time;

[0047] S3, chip support structure preparation; bonding is performed using glass material as the support structure of the chip, ensuring the stability of the chip;

[0048] S4, packaging and testing; the prepared MEMS pressure sensor chip is packaged to protect it from external environmental interference and damage, 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 application.

[0049] The working principle and use process of the application are as follows:

[0050] The micro-electromechanical chip 1 is accurately placed on the predetermined position on the mainboard, and the fixing cover 2 is placed above the micro-electromechanical 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, preventing misalignment during installation. Since each pin 3 is surrounded by two guide plates 2021, additional stability and accuracy are provided. As the fixing cover 2 continues to press down, the several cylinders 201 on the fixing cover 2 also move. The clamping blocks 2011 on these cylinders 201 move with the movement of the cylinders 201. The clamping blocks 2011 gradually approach the two clamping blocks 1012 on the fixing plate 101. When the clamping blocks 2011 contact the two clamping blocks 1012, due to the hinged design of the clamping blocks 1012, the clamping blocks 2011 will extrude the two clamping blocks 1012 outward. As the fixing cover 2 is further pressed down, the clamping blocks 2011 finally move to the lowest point of their stroke. At this time, the clamping blocks 2011 have been completely inserted between the two clamping blocks 1012. After the clamping blocks 2011 reach the lowest point, the fixing cover 2 is released, and the cylinders 201 and clamping blocks 2011 on the fixing cover 2 are no longer subjected to downward pressure. After the fixing cover 2 is released, the spring 1013 on the fixing plate 101 begins to rebound, driving the two clamping blocks 1012 to move towards the middle, thereby clamping the clamping blocks 2011, ensuring the firm fixation between the micro-electromechanical chip 1 and the fixing cover 2.

[0051] It is to be understood that the terminology used herein such as first and second, and the like, is only used to distinguish one entity or action from another entity or action, and does not necessarily require or imply any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0052] While embodiments of the present application have been shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application. The scope of the application is defined by the appended claims and their equivalents.

Claims

1. A MEMS pressure sensor comprising a microelectromechanical chip (1), characterized in that: The outer wall of the micro machine chip (1) is slidably provided with a fixed cover (2), the top of the two sides of the micro machine chip (1) is respectively provided with a plurality of pins (3), the outer wall of the two sides of the fixed cover (2) is respectively provided with a plurality of installation grooves (202), and the inner wall of the plurality of installation grooves (202) is respectively provided with the same guide mechanism. The guide mechanism comprises two guide plates (2021) hingedly connected to the inner wall of the installation groove (202), the two guide plates (2021) are respectively elastically connected to the side of the installation groove (202) by the second spring (2022), and the two guide plates (2021) are slidably connected to the corresponding pin (3). The front and back of the micro machine chip (1) is respectively provided with a plurality of buckle mechanisms. The top inner wall of the fixed cover (2) is fixedly provided with a plurality of cylinders (201), and the bottom of the plurality of cylinders (201) is respectively fixedly provided with a clamping block (2011). The buckle mechanism comprises two fixed blocks (1011) fixedly connected to the top of the fixed plate (101), two clamping blocks (1012) are hingedly connected to the side of the two fixed blocks (1011) close to each other, the two clamping blocks (1012) are hingedly connected, the top of the two clamping blocks (1012) is respectively elastically connected to the fixed plate (101) by the first spring (1013), and the two clamping blocks (1012) are respectively connected to the corresponding clamping block (2011).

2. The MEMS pressure sensor of claim 1, wherein: The installation groove (202) is designed as a trapezoidal structure, and the second spring (2022) is arranged at the position of the two waists at the bottom of the installation groove (202).

3. The MEMS pressure sensor of claim 1, wherein: The pin (3) adopts S-shaped design, the cross-sectional area of the turning part of the pin (3) is larger than that of the two ends, a crescent groove is formed in the outer wall of the turning part of the pin (3), and the crescent groove penetrates from one side of the pin (3) to the other side.

4. The MEMS pressure sensor of claim 1, wherein: The bottom of the two guide plates (2021) is inclined on the side close to each other, and the inclination angles of the two guide plates (2021) are symmetrically distributed.

5. The MEMS pressure sensor of claim 1, wherein: The top of the fixed cover (2) is fixedly provided with a hollow column (203), and the hollow column (203) is slidably connected to the micro machine chip (1).

6. The MEMS pressure sensor of claim 1, wherein: The two fixed plates (101) are designed as right-angled triangles, and the buckle mechanism and the micro machine chip (1) are fixedly connected to the right-angle side of the fixed plate (101).

7. The MEMS pressure sensor of claim 1, wherein: The front and back of the micro machine chip (1) is respectively provided with a plurality of sliding grooves (102), and the plurality of sliding grooves (102) are semicircular, and the diameter of the semicircle is equal to the diameter of the cylinder (201).

8. The MEMS pressure sensor of claim 1, wherein: The plurality of buckle mechanisms are linearly arranged, and the distance between adjacent two buckle mechanisms is the same.

9. A method of manufacturing a MEMS pressure sensor, applied to the MEMS pressure sensor of any one of claims 1-8, characterized in that: The specific steps of the preparation method include: S1, preparing pressure resistance and metal interconnection lead: selecting a silicon wafer as a substrate, forming a thin film on the silicon wafer through a silicon nitride thin film thermal deposition process, forming a pattern on the thin film by using a photoetching technology, and preparing a pressure resistance and a metal interconnection lead by using 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, preparing a chip support structure; using a glass material for bonding, as a support structure of the chip; S4, packaging and testing; packaging the prepared MEMS pressure sensor chip, and testing the performance of the packaged sensor.

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