Pressure sensing module, preparation method and pressure sensor

Abstract

The invention provides a pressure sensing module, a preparation method and a pressure sensor, and relates to the technical field of micro-electronic machinery, and the precision of the pressure sensing module is further improved by arranging a boss structure. The pressure sensing module comprises a first substrate and a second substrate, wherein the first substrate comprises a piezoresistor and a boss structure; the second substrate is located on one side of the first substrate in the thickness direction of the second substrate; a cavity is formed between the first substrate and the second substrate; wherein the piezoresistor and the boss structure are arranged on one side, far away from the second substrate, of the first substrate; the number of the boss structures is multiple, and the boss structures are symmetrically arranged relative to the center of the first substrate.

Description

Technical Field

[0001] This application relates to the field of microelectromechanical technology, and particularly to a pressure sensing module, a preparation method thereof, and a pressure sensor. Background Art

[0002] A microelectromechanical system (MEMS) pressure sensing module is a miniature device with pressure detection capabilities prepared by MEMS technology, mainly divided into three categories: piezoresistive, capacitive, and resonant, and can be applied to fields such as consumer electronics and industrial production. Among them, the piezoresistive MEMS pressure sensing module has the advantages of small size, light weight, simple structure, low cost, and high measurement accuracy, so it has been widely used.

[0003] The sensitivity of the piezoresistors in the existing pressure sensing modules is relatively low, and there is a large deviation between the measured pressure and the actual value. Summary of the Invention

[0004] The present invention provides a pressure sensing module, a preparation method thereof, and a pressure sensor. The pressure sensing module further improves the accuracy of the pressure sensor by setting a boss structure.

[0005] In a first aspect, the present application provides a pressure sensing module. The pressure sensing module includes: a first substrate and a second substrate. The first substrate includes piezoresistors and a boss structure. The second substrate is located on one side of the first substrate in its own thickness direction. A cavity is formed between the first substrate and the second substrate. Among them, the piezoresistors and the boss structure are arranged on the side of the first substrate away from the second substrate. The number of boss structures is multiple, and the multiple boss structures are symmetrically arranged with respect to the center of the first substrate.

[0006] Based on the above solution, some embodiments of the present application provide a pressure sensing module. The pressure sensing module improves the sensitivity of the pressure sensing module through the boss structure. When an external pressure acts on the module, these boss structures serve as stress concentration points, and can more effectively convert the applied pressure into mechanical stress that the piezoresistors can sense, thereby improving the module sensitivity. At the same time, when the first substrate faces external pressure, due to the setting of the boss structure, the overall bending or deformation degree will be reduced, which helps to keep the piezoresistors working in a more stable stress state, reducing the non-linear error caused by excessive substrate deformation, and thus improving the measurement accuracy.

[0007] In some embodiments, the multiple boss structures and the multiple piezoresistors are arranged around the center of the first substrate.

[0008] In some embodiments, the number of the boss structures is four, and the four boss structures are arranged diagonally in pairs; the number of the varistors is four, and along the circumference of the first substrate, the four varistors and the four boss structures are arranged alternately.

[0009] In some embodiments, the shapes of the plurality of boss structures are the same and the areas are equal.

[0010] In some embodiments, the boss structure includes a first part and a second part, and the first part and the second part are connected to form an L shape.

[0011] In some embodiments, the varistor includes a first varistor and a second varistor, which are arranged adjacent to the boss structure and are respectively located at two ends of the boss structure; one end of the first part of the boss structure away from the second part is arranged opposite to the first varistor, and one end of the second part of the boss structure away from the first part is arranged opposite to the second varistor.

[0012] In some embodiments, the distance between the edge of the boss structure and two adjacent varistors is equal, and / or the distance between the varistor and the edges of two adjacent boss structures is equal.

[0013] In some embodiments, the distance between the edge of the boss structure and two adjacent varistors is greater than or equal to 20 μm and less than or equal to 50 μm.

[0014] In some embodiments, the dimension of the first part of the boss structure in the first direction is equal to the dimension of the second part of the boss structure in the second direction; wherein, the first direction is perpendicular to the extending direction of the first part of the boss structure, the second direction is perpendicular to the extending direction of the second part of the boss structure, and the extending directions of the first part and the second part of the boss structure are both perpendicular to the thickness direction of the boss structure.

[0015] In some embodiments, the dimension of the first part of the boss structure in the first direction is greater than or equal to 50 μm and less than or equal to 125 μm.

[0016] In some embodiments, the pressure sensing module further includes: an interconnection wire, which is electrically connected to the plurality of varistors; the interconnection wire is arranged around the plurality of varistors and the plurality of boss structures; wherein, the distances between the plurality of boss structures and the interconnection wire are equal.

[0017] In some embodiments, the distance between the plurality of boss structures and the interconnection wire is greater than or equal to 20 μm and less than or equal to 50 μm.

[0018] In some embodiments, they are formed in the same thin film preparation process and etching process; and / or, the thickness of the varistor is equal to that of the boss structure.

[0019] In some embodiments, the first substrate further includes: a device layer, a first buffer layer, and a buried oxide layer stacked on a side of the first buffer layer away from the second substrate; the first buffer layer, the buried oxide layer, and the device layer are stacked in sequence in a direction away from the second substrate; the varistor and the boss structure are disposed on a side of the buried oxide layer away from the first buffer layer; a groove is provided on a surface of the first buffer layer close to the second substrate, and the groove is used to form the cavity.

[0020] In a second aspect, the present application provides a method for manufacturing a pressure sensing module for manufacturing the pressure sensing module of any of the above embodiments; the manufacturing method includes: sequentially forming a buried oxide layer and an initial device layer on the first buffer layer; etching on the initial device layer to form the varistor and the boss structure, and the etched part exposes a side of the buried oxide layer away from the first buffer layer.

[0021] The beneficial effects of the method for manufacturing the pressure sensing module are the same as those of the pressure sensing module, and will not be elaborated herein.

[0022] In a third aspect, the present application provides a pressure sensor, which includes: a pressure sensing module and an integrated circuit, and the integrated circuit is electrically connected to the pressure sensing module.

[0023] The beneficial effects of the pressure sensor are the same as those of the pressure sensing module, and will not be elaborated herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the embodiments of the present disclosure, and constitute a part of the embodiments of the present disclosure. The schematic embodiments of the present disclosure and their descriptions are used to explain the present disclosure, and do not constitute an improper limitation to the present disclosure. In the drawings:

[0025] Figure 1 A schematic diagram of a pressure sensing module provided by some embodiments of the present disclosure;

[0026] Figure 2 A schematic diagram of the front surface of a first substrate provided by some embodiments of the present disclosure;

[0027] Figure 3 A schematic diagram of the back surface of a first substrate provided by some embodiments of the present disclosure;

[0028] Figure 4 A schematic diagram of a pressure sensor provided by some embodiments of the present disclosure;

[0029] Figure 5 Schematic diagram of an electronic device provided for some embodiments of the present disclosure.

[0030] Reference numerals

[0031] 10. First substrate; 20. Second substrate; 11. Varistor; 12. Boss structure; 121. First part; 122. Second part; 13. Device layer; 14. Buried oxide layer; 15. First substrate layer; 16. First metal layer; 17. First connection layer; 18. Metal pad; 19. Interconnecting wire; 21. Second substrate layer; 22. Second metal layer; 23. Second connection layer; N. Cavity; 100. Pressure sensing module; 150. Integrated circuit; 200. Pressure sensor; 300. Electronic device; 310. Housing. Detailed implementation manners

[0032] Next, the technical solutions in some embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art shall fall within the protection scope of the present application.

[0033] Unless otherwise required by the context, throughout the specification and claims, the term "comprising" is interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples" or "some examples", etc., are intended to indicate that specific features, structures, materials or characteristics related to the embodiment or example are included in at least one embodiment or example of the present application. The schematic representations of the above terms are not necessarily referring to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0034] A micro-electro-mechanical system (MEMS) pressure sensing module is a miniature device with pressure detection capabilities prepared by MEMS technology, mainly divided into three categories: piezoresistive, capacitive, and resonant, and can be applied to fields such as consumer electronics and industrial production. Among them, the piezoresistive MEMS pressure sensing module has the advantages of small size, light weight, simple structure, low cost, and high measurement accuracy, so it has been widely used.

[0035] The sensitivity of the varistor in the existing pressure sensing module is relatively low, and there is a large deviation between the measured pressure and the actual value.

[0036] It should be noted that the piezoresistive MEMS pressure sensing module includes a piezoresistive film (which can also be called a strain film), piezoresistors, and a circuit structure, and the piezoresistors and the circuit structure are electrically connected. The working principle of the piezoresistive MEMS pressure sensing module can be as follows: by fabricating piezoresistors on the strain film, the strain film deforms under the action of an external pressure to generate stress, the piezoresistors change their resistance values under the action of the stress, and finally, the resistance value change is converted into a voltage output through an interconnection structure (such as a Wheatstone bridge). Therefore, the magnitude of the external pressure can be reflected by the voltage output value.

[0037] Based on this, some embodiments of the present application provide a pressure sensing module. As Figure 1 shown, the pressure sensing module 100 includes: a first substrate 10 and a second substrate 20.

[0038] The first substrate 10 includes piezoresistors 11 and a boss structure 12; the second substrate 20 is located on one side of the first substrate 10 in its own thickness direction;

[0039] A cavity is formed between the first substrate 10 and the second substrate 20; wherein, the piezoresistors 11 and the boss structure 12 are disposed on a side of the first substrate 10 away from the second substrate 20; the number of the boss structures 12 is multiple, and the multiple boss structures 12 are symmetrically arranged with respect to the center of the first substrate 10.

[0040] First, the design of the boss structure 12 creates local structural changes on the first substrate 10. When an external pressure acts on the module, these boss structures 12 act as stress concentration points and can more effectively convert the applied pressure into mechanical stress that the piezoresistors 11 can sense. This means that, compared with a planar substrate without the boss structure 12, the boss structure 12 can enable more external forces to be converted into changes in resistance values, thereby improving the sensitivity of pressure sensing.

[0041] Although the boss structure 12 reduces the directly pressurized planar area, they actually increase the effective area of indirect contact with the piezoresistors 11 through their geometric shapes (usually convex or columnar), especially in the case of uneven pressure distribution. This design helps to more effectively capture and transmit pressure changes, enabling even small pressure changes to be sensed by the piezoresistors 11 and converted into electrical signals.

[0042] The multiple boss structures 12 are symmetrically arranged with respect to the center of the first substrate 10. For example, there are two boss structures 12, and the two boss structures 12 are symmetrically arranged with respect to the center of the first substrate 10.

[0043] This setting method not only enhances the structural stability of the module but also optimizes the stress transfer path from the outside of the module to the varistor 11. This design reduces stress loss, ensuring that pressure changes can act on the varistor 11 more directly and efficiently, thereby improving the sensing efficiency and sensitivity.

[0044] Based on the above solution, some embodiments of the present application provide a pressure sensing module 100. The pressure sensing module 100 improves the sensitivity of the pressure sensing module 100 through the boss structure 12. When an external pressure acts on the module, these boss structures 12 serve as stress concentration points, which can more effectively convert the applied pressure into mechanical stress that the varistor 11 can sense, thereby improving the module sensitivity. At the same time, when the first substrate faces external pressure, due to the setting of the boss structure, the overall bending or deformation degree will be reduced, which helps to keep the varistor working in a more stable stress state, reducing the non-linear error caused by excessive substrate deformation, thereby improving the measurement accuracy.

[0045] As Figure 1 shown, a plurality of the boss structures 12 and a plurality of the varistors 11 are arranged around the center of the first substrate 10.

[0046] Among them, the boss structures 12 and varistors 11 arranged around the center can capture pressure changes from all directions more evenly. This design reduces the measurement error caused by uneven pressure distribution, enabling the module to more accurately reflect the real pressure situation.

[0047] And the boss structure 12, as a stress concentration point, can more effectively convert the applied pressure into mechanical stress that the varistor 11 can sense. When a plurality of boss structures 12 and varistors 11 are arranged around the center, they can form a denser stress sensing network, thereby increasing the sensitivity of the module to small pressure changes. This design also enables the module to better adapt to pressure sources of different sizes and shapes because the pressure can be evenly transmitted to the varistor 11 through multiple paths.

[0048] As Figure 1 shown, in some embodiments, the number of the boss structures 12 is four, and the four boss structures 12 are arranged diagonally in pairs.

[0049] The number of the varistors 11 is four. Along the circumferential direction of the first substrate 10, the four varistors 11 and the four boss structures 12 are arranged alternately.

[0050] Among them, the layout in which the varistors 11 and the boss structures 12 are arranged alternately enables each varistor 11 to be closer to its corresponding boss structure 12. In this way, when the boss structure 12 is subjected to pressure, the stress can be more directly transmitted to the adjacent varistor 11, thereby improving the sensitivity of the module.

[0051] As Figure 1 shown, in some embodiments, the shapes of the plurality of boss structures 12 are the same and the areas are equal.

[0052] The boss structures 12 with the same shape and area can disperse stress in the same way and to the same extent when subjected to external pressure. This helps to achieve a more uniform stress distribution, and the uniform stress distribution also means that each varistor 11 can receive a similar stress input, thereby improving the accuracy and consistency of the measurement.

[0053] As Figure 1 and Figure 2 shown, in some embodiments, the boss structure 12 includes a first part 121 and a second part 122, and the first part 121 and the second part 122 are connected to form an L shape.

[0054] The varistor 11 includes a first varistor 11 and a second varistor 11, which are arranged adjacent to the boss structure 12 and are respectively located at both ends of the boss structure 12.

[0055] One end of the first part 121 of the boss structure 12 away from the second part 122 is disposed opposite to the first varistor 11, and one end of the second part 122 of the boss structure 12 away from the first part 121 is disposed opposite to the second varistor 11.

[0056] That is to say, the L-shaped boss structure 12 is formed by connecting the first part 121 and the second part 122 to each other.

[0057] In some embodiments, as Figure 1 and Figure 2 shown, the distance between one end of the first part 121 of the boss structure 12 away from the second part 122 and the first varistor 11 is equal to the distance between one end of the second part 122 of the boss structure 12 away from the first part 121 and the second varistor 11. That is to say, the distances between the edges of the boss structure 12 and the adjacent two varistors 11 are equal.

[0058] In some embodiments, the distances between the edges of the boss structure 12 and the adjacent two varistors 11 are equal, and / or the distances between the varistor 11 and the edges of the adjacent two boss structures 12 are equal.

[0059] For example, only the distance between the edge of the boss structure 12 and two adjacent varistors 11 is equal, or the distance between the varistor 11 and the edges of two adjacent boss structures 12 is equal; or the distance between the edge of the boss structure 12 and two adjacent varistors 11 is equal, and the distance between the varistor 11 and the edges of two adjacent boss structures 12 is equal.

[0060] In some embodiments, the distance L1 between the end of the first part 121 of the boss structure 12 away from the second part 122 and the first varistor 11 is greater than or equal to 20 μm and less than or equal to 50 μm.

[0061] That is to say, the distance L1 between the edge of the boss structure 12 and two adjacent varistors 11 is greater than or equal to 20 μm and less than or equal to 50 μm.

[0062] Refer to Figure 2 In some embodiments, the dimension of the first part 121 of the boss structure 12 in the first direction X is equal to the dimension of the second part 122 of the boss structure in the second direction Y.

[0063] Wherein, the first direction X is perpendicular to the extending direction of the first part 121 of the boss structure 12, the second direction Y is perpendicular to the extending direction of the second part 122 of the boss structure 12, and the extending directions of both the first part 121 and the second part 122 of the boss structure 12 are perpendicular to the thickness direction Z of the boss structure 12.

[0064] The dimension of the first part 121 of the boss structure 12 in the first direction X is equivalent to the width of the first part 121 of the boss structure 12, and the dimension of the second part 122 of the boss structure in the second direction Y is equivalent to the width of the second part 122 of the boss structure 12.

[0065] In some embodiments, the width L2 of the first part 121 of the boss structure 12 is greater than or equal to 50 μm and less than or equal to 125 μm.

[0066] Among them, the larger the area of the L-shaped boss structure 12, the lower the sensitivity will be accordingly. The distance between the end of the first part 121 of the boss structure 12 away from the second part 122 and the first varistor 11 being greater than or equal to 20 μm is to prevent crosstalk between the boss structure 12 and other structures; the width of the first part 121 of the boss structure 12 being less than or equal to 125 μm is to avoid the width of the boss structure 12 exceeding the length of the varistor 11, thereby affecting the stress distribution in the varistor 11 region.

[0067] Such as Figure 1 and Figure 2As shown, in some embodiments, the pressure sensing module 100 further includes: an interconnection wire 19, which is electrically connected to a plurality of piezoresistors 11; the interconnection wire 19 is disposed around the plurality of piezoresistors 11 and a plurality of boss structures 12; wherein, the distances between the plurality of boss structures 12 and the interconnection wire 19 are equal.

[0068] In some embodiments, the distance L3 between the plurality of boss structures 12 and the edge of the cavity is greater than or equal to 20 μm and less than or equal to 50 μm.

[0069] In some embodiments, the piezoresistors 11 and the boss structures 12 are made of the same material; and / or, the piezoresistors 11 and the boss structures 12 have the same thickness.

[0070] The piezoresistors 11 and the boss structures 12 being made of the same material means that the piezoresistors 11 and the boss structures 12 are formed in the same thin film preparation process and etching process.

[0071] In some embodiments, the first substrate 10 further includes: a first buffer layer 15, and a buried oxide layer 14 stacked on the side of the first buffer layer 15 away from the second substrate 20; the piezoresistors 11 and the boss structures 12 are disposed on the side of the buried oxide layer 14 away from the first buffer layer 15; a groove is provided on the surface of the first buffer layer 15 close to the second substrate 20, and the groove is used to form a cavity.

[0072] As Figure 1 shown, the first substrate 10 further includes: a device layer 13, a first metal layer 16, and a first connection layer 17. The device layer 13 is etched to form the piezoresistors 11 and the boss structures 12.

[0073] The first metal layer 16 is annular, and the first metal layer 16 is connected to the non-cavity N part of the first buffer layer 15 close to the side away from the buried oxide layer 14; one side of the first connection layer 17 close to the first metal layer 16 is connected to the first metal layer 16, and the side away from the first metal layer 16 is connected to the second substrate 20.

[0074] The width of the first metal layer 16 is greater than 600 μm, the distance between the side of the first metal layer 16 away from the cavity N and the boundary of the first substrate 10 is greater than or equal to 50 μm; the distance between the side of the first metal layer 16 close to the cavity N and the boundary of the cavity N is greater than 50 μm. The thickness of the first connection layer 17 is 10 - 60 μm.

[0075] The second substrate 20 includes: a second buffer layer 21, a second metal layer 22, and a second connection layer 23.

[0076] The second metal layer 22 is annular, and one side of the second metal layer 22 away from the first substrate 10 is connected to the second substrate layer 21; one side of the second connection layer 23 away from the first substrate 10 is connected to the second metal layer 22, and one side close to the first substrate 10 is connected to the first substrate 10.

[0077] The width of the second metal layer 22 is greater than 600 μm, and the distance between one side of the second metal layer 22 away from the cavity N and the boundary of the second substrate 20 is greater than 50 μm; the distance between one side of the second metal layer 22 close to the cavity N and the boundary of the cavity N is greater than 50 μm. The thickness of the second connection layer 23 is 10 - 60 μm.

[0078] Exemplarily, the material of the first metal layer 16 or the second metal layer 22 can be a Cr / Au layer, a Ti / Cr / Au layer, a Cr / Ni / Au layer, etc.

[0079] The first substrate 10 includes four varistors 11 and four metal pads 18. The four varistors 11 are connected in series in sequence and are connected end to end to form a loop circuit.

[0080] Among them, the four varistors 11 are located at the central positions of the four diaphragm edges of the varistor film (refer to Figure 2 ), the edge distances of the four resistor films are kept the same and are a certain value between 0 - 20 μm, the widths of the four varistors 11 are the same as the total lengths, and the number of folds can be 1 - 10 folds. Among them, the structural dimensions of the upper and lower two varistors 11 are the same, and the structural dimensions of the left and right two varistors 11 are the same. In this application, it is two folds.

[0081] Exemplarily, the material of the interconnecting wire 19 can be a low-resistivity material, such as any one or a combination of Al, Ti / Al, Au, and Cr / Au. In this way, a good circuit path can be formed.

[0082] In this way, the varistor 11 is located on the first substrate 10, the interconnecting wire 19 is located on the first substrate 10, the varistor 11 and the interconnecting wire 19 are electrically connected, and the multiple metal pads 18 are connected to the middle sections of the interconnecting wire 19, that is, the four corners of the first substrate 10, thereby forming a Wheatstone bridge structure.

[0083] The Wheatstone bridge structure includes: an input terminal, two output terminals, and a ground terminal.

[0084] Among them, it should be noted that the two output terminals of the Wheatstone bridge structure are located diagonally, and there are no requirements for the positions of the input terminal and the ground terminal.

[0085] The metal pad 18 can be in structures such as square, rectangular, circular, oval, etc., and the side length or straight dimension L1” of the pad is 50 - 150 μm.

[0086] In some embodiments, the first substrate layer 15 is a SOI substrate layer. The SOI substrate layer can etch a part of the substrate layer to form a cavity, and a pressure-sensitive film can be formed inside the cavity. Refer to Figure 1 and Figure 3 , the cavity is a square cavity N, and the side length of the cavity N can be: 500 - 2000 μm.

[0087] Exemplarily, the material of the first substrate layer 15 can be silicon. The material of the buried oxide layer 14 can be an insulating material, such as any one or a combination of SiO2, SiN, and glass. At this time, the first substrate layer 15 and the buried oxide layer 14 can form a pressure-sensitive film.

[0088] That is to say, in the area where the piezoresistor 11 is located, the area where the pressure-sensitive film is located is opposite to the orthographic projection of the plurality of piezoresistors 11 on the first substrate layer 15, and is located within the area where the pressure-sensitive film is located. The first metal layer 16 and the first connection layer 17 surround it from above, and the second metal layer 22 and the second connection layer 23 surround it from below. The second metal layer 22 and the second connection layer 23 are then fixed to the second substrate layer 21, so as to form a sealed or vacuum structure.

[0089] Exemplarily, the material of the first connection layer 17 or the second connection layer 23 can be a eutectic solder, such as any one or a combination of AuSn, AgSn, CuSn, and SnAgCu.

[0090] In some embodiments, the first substrate 10 and the second substrate 20 enclose to form a vacuum cavity N.

[0091] In some embodiments, when the first substrate 10 and the second substrate 20 enclose to form a vacuum cavity N, the pressure sensing module 100 further includes a getter located inside the vacuum cavity N.

[0092] The above pressure sensing module 100 is an absolute pressure type pressure sensing module 100, which can measure the absolute value of the pressure change, and has the advantages of high precision and large measurement range; however, in some measurements regarding water pressure and air pressure, the absolute pressure type pressure sensing module 100 is not suitable. Therefore, a gauge pressure type pressure sensing module 100 is proposed as follows:

[0093] In some embodiments, the second substrate layer 21 is provided with a through hole; the through hole can connect the back of the diaphragm with the outside atmosphere to realize the gauge pressure / differential pressure measurement of the pressure sensing module 100.

[0094] Here, there is no limit on the size of the through hole. In some examples, the aperture of the through hole 50 ranges from 0 to 100 μm, such as 0 μm, 10 μm, 30 μm, 50 μm, 70 μm, or 100 μm, etc.

[0095] Exemplarily, an insulating layer may be provided on the sidewall of the through hole ( Figure 1 not shown in the figure), so that the safety and reliability of the pressure sensing module 100 can be improved.

[0096] It can be understood that the gauge pressure cavity N is the aforementioned cavity N. By using the through hole 50, the gauge pressure cavity N can be communicated with the external atmospheric environment, so that the pressure in the gauge pressure cavity N is equal to the external pressure; moreover, when the first substrate 10 and the second substrate 20 enclose to form the gauge pressure cavity N, the pressure sensing module 100 is a gauge pressure type pressure sensing module 100, which can be measured with the atmospheric pressure as the reference object and has the advantage of being easy to fabricate, and can be applied to measure the relative pressure change values of media such as water pressure and air pressure.

[0097] The present application also provides a preparation method of a pressure sensing module for preparing the above-mentioned pressure sensing module.

[0098] The preparation method includes:

[0099] S1. Form a buried oxide layer 14 and an initial device layer on the first buffer layer 15 in sequence.

[0100] S2. Etch on the initial device layer to form a piezoresistor 11 and a boss structure 12, and the etched part exposes the side of the buried oxide layer 14 away from the first buffer layer 15.

[0101] As Figure 3 and Figure 4 shown, some embodiments of the present disclosure also provide a pressure sensor 200. The pressure sensor 200 includes a pressure sensing module 100 and an integrated circuit 150 provided by the above technical solution.

[0102] The integrated circuit 150 is electrically connected to the metal pad 18 of the pressure sensing module 100.

[0103] It can be understood that when the piezoresistor 11 receives pressure, it generates a voltage signal and transmits the voltage signal to the integrated circuit 150. The integrated circuit 150 can further process the voltage signal to output a digital signal to feedback the magnitude of the pressure. In this way, the transmission of pressure measurement data can be realized.

[0104] As Figure 5 shown, some embodiments of the present disclosure also provide an electronic device 300. The electronic device 300 includes a housing 310 and a pressure sensor 200 disposed on the housing 310.

[0105] In some examples, the electronic device 300 may be a mobile phone or a computer; it may also be a portable electronic device 300, so that the pressure sensing module 100 can be applied to technical scenarios such as automobiles and process production that require pressure measurement.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A pressure sensing module, characterized in that: include: A first substrate including a varistor and a boss structure; A second substrate is located on one side of the first substrate in the thickness direction thereof; a cavity is formed between the first substrate and the second substrate; The varistor and the boss structure are arranged on a side of the first substrate away from the second substrate; there are multiple boss structures, and the multiple boss structures are symmetrically arranged relative to the center of the first substrate.

2. The pressure sensing module according to claim 1, characterized in that: A plurality of the boss structures and a plurality of the varistors are arranged around the center of the first substrate.

3. The pressure sensing module according to claim 1, characterized in that: The number of the boss structures is four, and the four boss structures are arranged diagonally in pairs; The number of the varistors is four, and along the circumference of the first substrate, the four varistors and the four boss structures are alternately arranged.

4. The pressure sensing module according to claim 1, characterized in that: The plurality of boss structures have the same shape and the same area.

5. The pressure sensing module according to claim 1, characterized in that: The boss structure includes a first part and a second part, and the first part and the second part are connected to form an L shape.

6. The pressure sensing module according to claim 5, characterized in that: The varistor comprises a first varistor and a second varistor, which are arranged adjacent to the boss structure and are respectively located at two ends of the boss structure; One end of the first part of the boss structure away from the second part is arranged opposite to the first varistor, and one end of the second part of the boss structure away from the first part is arranged opposite to the second varistor.

7. The pressure sensing module according to claim 6, characterized in that: The distance between the edge of the boss structure and two adjacent varistors is equal, and / or the distance between the varistor and the edge of two adjacent boss structures is equal.

8. The pressure sensing module according to claim 7, characterized in that: The distance between the edge of the boss structure and two adjacent varistors is greater than or equal to 20 μm and less than or equal to 50 μm.

9. The pressure sensing module according to claim 5, characterized in that: The size of the first part of the boss structure in the first direction is equal to the size of the second part of the boss structure in the second direction; Among them, the first direction is perpendicular to the extension direction of the first part of the boss structure, the second direction is perpendicular to the extension direction of the second part of the boss structure, and the extension direction of the first part of the boss structure and the extension direction of the second part of the boss structure are both perpendicular to the thickness direction of the boss structure.

10. The pressure sensing module according to claim 9, characterized in that: A size of the first portion of the boss structure in the first direction is greater than or equal to 50 μm and less than or equal to 125 μm.

11. The pressure sensing module according to claim 1, characterized in that: The pressure sensing module also includes: Interconnecting wires, the interconnecting wires are electrically connected to the plurality of varistors; the interconnecting wires are arranged around the plurality of varistors and the plurality of boss structures; Wherein, the spacings between the plurality of boss structures and the interconnection wires are equal.

12. The pressure sensing module according to claim 11, characterized in that: The spacing between the plurality of boss structures and the interconnection wires is greater than or equal to 20 μm and less than or equal to 50 μm.

13. The pressure sensing module according to any one of claims 1 to 12, characterized in that: The varistor and the boss structure are prepared and formed in the same thin film preparation process and etching process; and / or, The thickness of the varistor and the boss structure are equal.

14. The pressure sensing module according to any one of claims 1 to 12, characterized in that: The first substrate further comprises: a device layer, a first substrate layer, and a buried oxide layer stacked on a side of the first substrate layer away from the second substrate; the first substrate layer, the buried oxide layer and the device layer are stacked in sequence in a direction away from the second substrate; The varistor and the boss structure are arranged on a side of the buried oxide layer away from the first substrate layer; A surface of the first substrate layer close to the second substrate is provided with a groove, and the groove is used to form the cavity.

15. A method for preparing a pressure sensing module, characterized in that: Used for preparing a pressure sensing module as claimed in any one of claims 1 to 14; The preparation method comprises: forming a buried oxide layer and an initial device layer in sequence on the first substrate layer; The varistor and the boss structure are formed by etching on the initial device layer, and the etched and removed portion exposes a side of the buried oxide layer away from the first substrate layer.

16. A pressure sensor, characterized in that: include: The pressure sensing module according to any one of claims 1 to 14; The integrated circuit is electrically connected to the pressure sensing module.

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