Pressure sensor and its fabrication method

Abstract

A pressure sensor and its fabrication method are disclosed. The pressure sensor includes: a substrate, comprising a first surface, a second surface, and a back cavity; a pressure-sensing component mounted on the substrate, comprising a pressure-sensing membrane and at least one island-shaped structure, wherein the orthographic projection of the island-shaped structure onto the plane of the substrate at least partially overlaps with the orthographic projection of the back cavity onto the plane of the substrate; the back cavity exposes a portion of the island-shaped structure; wherein the island-shaped structure comprises an island body, an island connecting portion, and a suspended island arranged sequentially along a direction perpendicular to the plane of the substrate, the island body being connected to the pressure-sensing membrane, and the suspended island being closer to the second surface than the island body; the orthographic projections of the island body and the suspended island onto the plane of the substrate both include the orthographic projection of the island connecting portion onto the plane of the substrate, which can increase the area in the pressure-sensing component that is not easily deformed, reduce the overall deformation, and improve linearity.

Description

Technical Field

[0001] This article relates to, but is not limited to, the field of microelectromechanical systems (MEMS) technology, and in particular to a pressure sensor and its fabrication method. Background Technology

[0002] Pressure sensors are widely used in consumer electronics, medical, automotive, and industrial control fields. As a crucial bridge for converting external pressure signals into readable data, their performance and characteristics have a decisive impact on the accuracy and efficiency of application systems. Traditional pressure sensors, despite using robust materials such as metal thin films and ceramic thin films, are limited by their inherent properties such as large size, high power consumption, and low integration, making it difficult to meet the urgent demands of modern technology for precision and portability. With the rapid development of Micro-Electro-Mechanical Systems (MEMS) technology, MEMS pressure sensors, with their significant advantages such as miniaturization, low power consumption, multi-functional integration, and cost-effectiveness, are gradually becoming the market mainstream and accelerating the replacement of traditional pressure sensors.

[0003] Existing MEMS pressure sensor technology has significant shortcomings in terms of thin film thickness control, linearity and sensitivity improvement, miniaturization and integration design, cost control and production efficiency. Summary of the Invention

[0004] This disclosure provides a pressure sensor and its fabrication method. The pressure sensor provided by this disclosure can solve the problems of existing pressure sensors, such as the lack of a non-deformable area, large overall deformation, and poor linearity.

[0005] On one hand, embodiments of this disclosure provide a pressure sensor, including: The substrate includes a first surface, a second surface, and a back cavity, wherein the first surface and the second surface are disposed opposite to each other, and the back cavity is recessed from the second surface toward the first surface; A pressure-sensitive component is mounted on the substrate and includes a pressure-sensitive film and at least one island structure, wherein the orthographic projection of the island structure onto the plane of the substrate at least partially overlaps with the orthographic projection of the back cavity onto the plane of the substrate, and the back cavity exposes a portion of the island structure. The island structure includes an island, an island connecting portion, and a suspended island arranged sequentially along a direction perpendicular to the plane of the substrate. The island is connected to the pressure-sensitive membrane, and the suspended island is closer to the second surface than the island. The orthographic projections of the island and the suspended island onto the plane of the substrate both include the orthographic projection of the island connecting portion onto the plane of the substrate.

[0006] In some exemplary embodiments, the pressure-sensing component further includes at least one beam-shaped structure, and all the island-shaped structures are connected to the beam-shaped structure; the beam-shaped structure includes a beam body, a beam connecting portion, and a suspension beam arranged sequentially along a direction perpendicular to the plane of the substrate, and the beam body is connected to the pressure-sensing membrane, and the suspension beam is closer to the second surface than the beam body; The orthographic projections of the beam and the suspension beam onto the plane of the substrate both include the orthographic projection of the beam connection portion onto the plane of the substrate.

[0007] In some exemplary embodiments, the pressure-sensing component includes a beam-like structure that extends along a first direction and is connected to the substrate at both ends along the first direction. The pressure-sensing component includes four spaced-apart island structures, which are located on both sides of the beam structure along the second direction, with two island structures distributed on each side; the first direction intersects the second direction and the plane formed by them is parallel to the plane of the substrate.

[0008] In some exemplary embodiments, the pressure sensor further includes at least one limiting platform, and the limiting platform is located between the pressure-sensitive diaphragm and the second surface; the limiting platform extends along the second direction and includes a first end and a second end disposed opposite to each other, and the first end is connected to the substrate, and the second end is a free end; The limiting platform is located between the two island-shaped structures distributed along the first direction, and the orthographic projection of the limiting platform and the beam-shaped structure on the plane where the substrate is located does not overlap.

[0009] In some exemplary embodiments, the four island structures are symmetrically distributed about the beam structure.

[0010] In some exemplary embodiments, the pressure sensor further includes a plurality of piezoresistive elements, all of which are mounted on the beam-shaped structure; the plurality of piezoresistive elements include at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element, and a fourth piezoresistive element, and the first piezoresistive element, the second piezoresistive element, the third piezoresistive element, and the fourth piezoresistive element are arranged sequentially at intervals along the first direction; the second piezoresistive element and the third piezoresistive element are located between two island-shaped structures along the first direction, and the first piezoresistive element and the fourth piezoresistive element are respectively located on both sides of the four island-shaped structures along the first direction.

[0011] In some exemplary embodiments, the pressure-sensing component includes a beam-like structure extending along a first direction, with both ends of the beam-like structure connected to the substrate along the first direction; the pressure-sensing component includes two island-like structures located on opposite sides of the beam-like structure along a second direction; the first direction and the second direction intersect and form a plane parallel to the plane containing the substrate.

[0012] In some exemplary embodiments, the pressure sensor further includes a plurality of piezoresistive elements, all of which are mounted on the beam-shaped structure; the plurality of piezoresistive elements include at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element, and a fourth piezoresistive element, which are arranged sequentially at intervals along the first direction; the first piezoresistive element and the second piezoresistive element are located on one side of the two island-shaped structures along the first direction, and the third piezoresistive element and the fourth piezoresistive element are located on the other side of the two island-shaped structures along the first direction.

[0013] In some exemplary embodiments, the pressure-sensing component includes four beam-shaped structures and one island-shaped structure, with the four beam-shaped structures distributed around the island-shaped structure. Each beam-shaped structure includes a first end and a second end disposed opposite to each other, the first end being connected to the island-shaped structure and the second end being connected to the substrate.

[0014] In some exemplary embodiments, the island structure has a first central axis extending along a first direction and a second central axis extending along a second direction; the four beam structures are symmetrical about the first central axis and about the second central axis; the first direction and the second direction intersect and form a plane parallel to the plane of the substrate.

[0015] In some exemplary embodiments, the pressure sensor further includes a plurality of piezoresistive elements, the plurality of piezoresistive elements including at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element and a fourth piezoresistive element, and the first piezoresistive element, the second piezoresistive element, the third piezoresistive element and the fourth piezoresistive element are respectively mounted on different beam-shaped structures.

[0016] In some exemplary embodiments, the pressure-sensing component includes an island-shaped structure, and the orthographic projection of the island-shaped structure onto the plane of the substrate is cross-shaped, with the pressure-sensing membrane disposed around the island-shaped structure.

[0017] In some exemplary embodiments, the pressure sensor further includes a plurality of piezoresistive elements, the plurality of piezoresistive elements including at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element and a fourth piezoresistive element, and the orthographic projections of the first piezoresistive element, the second piezoresistive element, the third piezoresistive element and the fourth piezoresistive element on the plane of the substrate at least partially overlap with the orthographic projection of the pressure-sensitive film on the plane of the substrate, and the plurality of piezoresistive elements are all mounted on the pressure-sensitive film.

[0018] In some exemplary embodiments, the substrate further includes a cavity and a release channel, and the cavity, the release channel and the back cavity are arranged sequentially along a direction perpendicular to the plane of the substrate, and the cavity and the back cavity are connected via the release channel, and the cavity is closer to the pressure-sensitive membrane than the back cavity, and the orthographic projection of the island structure onto the plane of the substrate is within the range of the orthographic projection of the release channel onto the plane of the substrate.

[0019] On the other hand, this disclosure provides a method for fabricating a pressure sensor, used to fabricate the pressure sensor described in any of the foregoing embodiments; the fabrication method includes: The substrate is etched to form a well array pattern, the well array pattern including multiple wells, the wells being recessed from the first surface toward the second surface, and the substrate located within the wells is etched away; The wells are subjected to high-temperature annealing to form the pressure-sensitive membrane and cavity. The substrate is etched to form the island-like structure.

[0020] In some exemplary embodiments, etching the substrate to form the island structure includes: The substrate is etched from one side of the second surface of the substrate to form a plurality of etch grooves, the substrate located within the etch grooves is etched away, and the etch grooves are not connected to the cavity; The substrate is etched based on the etching groove to form the back cavity, and the back cavity is connected to the cavity.

[0021] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. Other advantages of this application can be realized and obtained by means of the embodiments described in the description and the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0023] Figure 1A This is a top view schematic diagram of a pressure sensor according to an embodiment of the present disclosure; Figure 1B This is a bottom view schematic diagram of a pressure sensor according to an embodiment of the present disclosure; Figure 2A for Figure 1A A cross-sectional view at point AA in the middle; Figure 2B for Figure 1A Cross-sectional view of the area marked BB in the middle; Figure 2C for Figure 1A Cross-sectional view at the CC mark; Figure 3A This is a cross-sectional schematic diagram of a pressure sensor forming a well array pattern according to an embodiment of the present disclosure; Figure 3B This is a cross-sectional schematic diagram of a pressure sensor forming a pressure-sensitive diaphragm according to an embodiment of the present disclosure; Figure 3C This is a cross-sectional schematic diagram of a pressure sensor forming a Wheatstone bridge according to an embodiment of the present disclosure; Figure 3D This is a cross-sectional schematic diagram of an etched groove formed in a pressure sensor according to an embodiment of the present disclosure; Figure 4A This is a top view schematic diagram of the well array pattern of a pressure sensor according to an embodiment of the present disclosure; Figure 4B This is a top view schematic diagram of a well array pattern of a pressure sensor according to another embodiment of the present disclosure; Figure 4C This is a top view schematic diagram of the well array pattern of a pressure sensor according to yet another embodiment of the present disclosure; Figure 5A This is a top view schematic diagram of a pressure sensor according to another embodiment of the present disclosure; Figure 5B This is a bottom view schematic diagram of a pressure sensor according to another embodiment of the present disclosure; Figure 6A for Figure 5A A cross-sectional view at point AA in the middle; Figure 6B for Figure 5A Cross-sectional view of the area marked BB in the middle; Figure 6C for Figure 5A Cross-sectional view at the CC mark; Figure 7A This is a top view schematic diagram of a pressure sensor according to yet another embodiment of the present disclosure; Figure 7B This is a bottom view schematic diagram of a pressure sensor according to yet another embodiment of the present disclosure; Figure 8A This is a top view schematic diagram of a pressure sensor according to another embodiment of the present disclosure; Figure 8B This is a bottom view schematic diagram of a pressure sensor according to another embodiment of the present disclosure; Figure 9A This is a top view schematic diagram of a pressure sensor according to another embodiment of the present disclosure; Figure 9B This is a bottom view schematic diagram of a pressure sensor according to another embodiment of the present disclosure; Figure 9C for Figure 9A A cross-sectional view of the area marked DD. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The implementation can be carried out in many different forms. Those skilled in the art will readily understand that the methods and content can be transformed into one or more forms without departing from the spirit and scope of this disclosure. Therefore, this disclosure should not be construed as limited to the content described in the following embodiments. Without conflict, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other.

[0025] In the accompanying drawings, the size of one or more constituent elements, the thickness of layers, or areas are sometimes exaggerated for clarity. Therefore, this disclosure is not necessarily limited to these dimensions, and the shapes and sizes of the components in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate ideal examples, and this disclosure is not limited to the shapes or values ​​shown in the drawings.

[0026] The ordinal numbers such as "first," "second," and "third" in this disclosure are used to avoid confusion among the constituent elements, not to limit the quantity. "Multiple" in this disclosure includes two or more quantities.

[0027] In this disclosure, for convenience, terms such as "middle," "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate orientation or positional relationships in conjunction with the accompanying drawings. This is solely for the purpose of facilitating the description and simplification of the specification, and does not imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this disclosure. The positional relationships of the constituent elements may be appropriately changed depending on the direction in which the constituent elements are described. Therefore, the description is not limited to the terms used in the specification and may be appropriately replaced as appropriate.

[0028] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection via an intermediate component, or a connection within two components. Those skilled in the art will understand the meaning of these terms in this disclosure as appropriate.

[0029] In this disclosure, a transistor is a device that includes at least three terminals: a gate electrode, a drain electrode, and a source electrode. A transistor has a channel region between the drain electrode (drain electrode terminal, drain region, or drain) and the source electrode (source electrode terminal, source region, or source), and current can flow through the drain electrode, the channel region, and the source electrode. In this disclosure, the channel region refers to the region through which current primarily flows.

[0030] In this disclosure, the first electrode can be the drain electrode and the second electrode can be the source electrode, or vice versa. In cases where transistors with opposite polarities are used or the current direction changes during circuit operation, the functions of the "source electrode" and the "drain electrode" are sometimes interchanged. Therefore, in this disclosure, the "source electrode" and the "drain electrode" can be interchanged.

[0031] In this disclosure, "electrical connection" includes the situation where constituent elements are connected together by a component having a certain electrical function. There are no particular limitations on the "component having a certain electrical function," as long as it enables the transmission of electrical signals between the connected constituent elements. Examples of "component having a certain electrical function" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other components having one or more functions.

[0032] In this disclosure, "parallel" refers to a state in which the angle formed by two straight lines is greater than or equal to -10° and less than 10°, and therefore can include a state in which the angle is greater than or equal to -5° and less than 5°. Furthermore, "perpendicular" refers to a state in which the angle formed by two straight lines is greater than or equal to 80° and less than 100°, and therefore can include a state in which the angle is greater than or equal to 85° and less than 95°.

[0033] In this disclosure, the terms "film" and "layer" can be interchanged. For example, sometimes "conductive layer" can be replaced with "conductive film". Similarly, sometimes "insulating film" can be replaced with "insulating layer".

[0034] In this disclosure, “about” means a value that is not strictly limited and allows for process and measurement errors.

[0035] In the field of differential pressure sensors, with continuous technological breakthroughs and rapid market growth, the requirements for sensor performance are becoming increasingly stringent, including but not limited to high linearity, high sensitivity, excellent measurement resolution, compact size design, and cost-effectiveness. However, the design and manufacturing of differential pressure sensors still face numerous technical challenges, hindering further improvements in sensor accuracy, reliability, and sensitivity, becoming a key factor restricting industry development. The design and manufacturing of differential pressure sensors face three core challenges: first, fabricating ultra-thin pressure-sensitive films with thicknesses ranging from sub-micrometers to several micrometers, ensuring high consistency in thickness to significantly improve sensor sensitivity and accuracy; second, effectively optimizing the linearity and stress management strategies of the ultra-thin films to minimize nonlinear errors; and third, effectively optimizing the stress distribution of the pressure-sensitive film to concentrate stress distribution areas, facilitating piezoresistive strip arrangement and thus improving sensitivity. In existing MEMS pressure sensor technology, the pressure-sensitive film, as a core component, directly determines the overall performance of the sensor. However, existing pressure-sensitive film fabrication processes, besides the difficulty in forming ultra-thin films, also have many shortcomings. For example, the back-side bulk silicon etching process results in deep and large cavities with difficulty in controlling film thickness; the front-side bulk silicon etching combined with polysilicon deposition exhibits poor piezoresistive characteristics; silicon-silicon bonding processes are costly; and the sacrificial layer etching process for surface silicon has adhesion problems. The high cost and low production efficiency of SOI silicon wafers limit their application in large-scale production. Furthermore, the structural design of existing MEMS pressure sensors is often limited to simple single-layer silicon pressure-sensitive films, making it difficult to form complex silicon islands, beams, and other microstructures, thus limiting further improvements in sensor linearity, sensitivity, and stress management.

[0036] In summary, existing MEMS pressure sensor technologies have significant shortcomings in terms of thin film thickness control, linearity and sensitivity improvement, miniaturization and integration design, cost control and production efficiency.

[0037] Therefore, this disclosure provides a pressure sensor, the pressure sensor comprising: The substrate includes a first surface, a second surface, and a back cavity, wherein the first surface and the second surface are disposed opposite to each other, and the back cavity is recessed from the second surface toward the first surface; A pressure-sensitive component is mounted on the substrate and includes a pressure-sensitive film and at least one island structure, wherein the orthographic projection of the island structure onto the plane of the substrate at least partially overlaps with the orthographic projection of the back cavity onto the plane of the substrate, and the back cavity exposes a portion of the island structure. The island structure includes an island, an island connecting portion, and a suspended island arranged sequentially along a direction perpendicular to the plane of the substrate. The island is connected to the pressure-sensitive membrane, and the suspended island is closer to the second surface than the island. The orthographic projections of the island and the suspended island onto the plane of the substrate both include the orthographic projection of the island connecting portion onto the plane of the substrate.

[0038] The pressure sensor provided in this embodiment refines the island structure, designing it to include an island body, an island connecting portion, and a suspended island. The orthographic projections of the island body and the suspended island onto the plane of the substrate include the orthographic projections of the island connecting portion onto the plane of the substrate. This allows the suspended island to be in a suspended state, optimizes the overall force distribution of the pressure-sensing component, increases the area in the pressure-sensing component that is not easily deformed, reduces the overall deformation, and improves linearity.

[0039] Figure 1A This is a top view schematic diagram of a pressure sensor according to an embodiment of the present disclosure. Figure 1B This is a bottom view schematic diagram of a pressure sensor according to an embodiment of the present disclosure. Figure 1A , Figure 1B As shown, the pressure sensor may include a substrate 10 and a pressure-sensing component 20 connected to the substrate 10. The pressure-sensing component 20 may include a pressure-sensing membrane 21, multiple island structures 22, and a beam structure 23, wherein the multiple island structures 22 are all connected to the beam structure 23, and the orthographic projections of the multiple island structures 22 onto the plane of the substrate 10 do not overlap. For example, the pressure-sensing membrane 21, the multiple island structures 22, and the beam structure 23 may be integrally formed. For example, the pressure-sensing component 20 may include four island structures 22, which may be arranged in a rectangular array. The four island structures 22 can be designated as a first island structure 22-1, a second island structure 22-2, a third island structure 22-3, and a fourth island structure 22-4. The orthographic projection of each island structure 22 onto the plane of the substrate 10 can be rectangular. The orthographic projection of the beam structure 23 onto the plane of the substrate 10 can be a long strip extending along the first direction X. The four island structures 22 can be located on either side of the beam structure 23 along the second direction Y, and can be arranged symmetrically about the beam structure 23. The pressure-sensitive membrane 21 can include a first portion 21-1 and a second portion 21-2 spaced apart along the second direction Y, with the first portion 21-1 and the second portion 21-2 located on either side of the beam structure 23 along the second direction Y. In this embodiment, the first direction X intersects the second direction Y, and the plane formed is parallel to the plane of the substrate. Figure 1A , Figure 1B The use of different colors for different components does not indicate that different components are made of different materials; it is simply for the purpose of easy identification of different components.

[0040] In some exemplary embodiments, such as Figure 1A As shown, the pressure sensor may further include multiple conductive lines 30, multiple connecting electrodes 40, and multiple piezoresistive elements 50. For example, the multiple conductive lines 30 may include at least a first conductive line 31, a second conductive line 32, a third conductive line 33, and a fourth conductive line 34, and all of the multiple conductive lines 30 are located on the side of the pressure-sensing component 20 away from the substrate 10. The multiple connecting electrodes 40 may include at least a first connecting electrode 41, a second connecting electrode 42, a third connecting electrode 43, and a fourth connecting electrode 44. For example, the piezoresistive element 50 may be a piezoresistive resistor. The multiple piezoresistive elements 50 may include at least a first piezoresistive element 51, a second piezoresistive element 52, a third piezoresistive element 53, and a fourth piezoresistive element 54. A portion of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 may be embedded within the beam-like structure 23, and the beam-like structure 23 exposes at least a portion of the surface of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 on the side away from the substrate 10. The first piezoresistive element 51 may include two oppositely disposed ends. One end of the first piezoresistive element 51 may be connected to the first conductive line 31 via a first connecting electrode 41, and the other end of the first piezoresistive element 51 may be connected to the fourth conductive line 34 via another first connecting electrode 41. The second piezoresistive element 52 may include two oppositely disposed ends. One end of the second piezoresistive element 52 may be connected to the first conductive line 31 via a second connecting electrode 42, and the other end of the second piezoresistive element 52 may be connected to the second conductive line 32 via another second connecting electrode 42. The third piezoresistive element 53 may include two oppositely disposed ends. One end of the third piezoresistive element 53 may be connected to the third conductive line 33 via a third connecting electrode 43, and the other end of the third piezoresistive element 53 may be connected to the fourth conductive line 34 via another third connecting electrode 43. The fourth piezoresistive element 54 may include two oppositely disposed ends. One end of the fourth piezoresistive element 54 may be connected to the second conductive line 32 via a fourth connecting electrode 44, and the other end of the fourth piezoresistive element 54 may be connected to the third conductive line 33 via another fourth connecting electrode 44. In this embodiment of the disclosure, multiple conductive lines 30, multiple connecting electrodes 40, and multiple piezoresistive elements 50 can form a Wheatstone bridge.

[0041] In some exemplary embodiments, such as Figure 1AAs shown, the orthographic projections of the plurality of connecting electrodes 40 and the plurality of piezoresistive elements 50 onto the plane of the substrate 10 can lie within the orthographic projection of the beam-shaped structure 23 onto the plane of the substrate 10. A plurality of first connecting electrodes 41 and a plurality of first piezoresistive elements 51 constitute a first bridge arm; a plurality of second connecting electrodes 42 and a plurality of second piezoresistive elements 52 constitute a second bridge arm; a plurality of third connecting electrodes 43 and a plurality of third piezoresistive elements 53 constitute a third bridge arm; and a plurality of fourth connecting electrodes 44 and a plurality of fourth piezoresistive elements 54 constitute a fourth bridge arm. The second and third bridge arms are both located between the first island structure 22-1 and the second island structure 22-2. The first, second, third, and fourth bridge arms are arranged sequentially along the first direction X. The first bridge arm is located on the side of the first island structure 22-1 away from the second bridge arm, and the fourth bridge arm is located on the side of the second island structure 22-2 away from the third bridge arm.

[0042] In some exemplary embodiments, such as Figure 1A As shown, the island-shaped structure 22 has a first width W1 when projected onto the plane of the substrate 10, and the beam-shaped structure 23 has a second width W2 when projected onto the plane of the substrate 10. The first width W1 is greater than zero. For example, the first width W1 can be greater than the second width W2, or the first width W1 can be equal to half of the second width W2, etc. By setting the island-shaped structure 22 and the beam-shaped structure 23, the force of the pressure sensor can be concentrated on the beam-shaped structure, which can improve the test sensitivity. Furthermore, the beam-shaped structure 23 can reduce the deformation of the pressure-sensitive diaphragm 21, which can improve linearity. The width refers to the smaller dimension along the first direction and the second direction.

[0043] In some exemplary embodiments, such as Figure 1A As shown, two adjacent island structures 22 located on the same side of the beam structure 23 have a distance L along the first direction X. The distance L can range from tens of micrometers to thousands of micrometers and can be adjusted according to the size of the entire pressure sensor.

[0044] In some exemplary embodiments, such as Figure 1A As shown, the pressure sensor may further include multiple external electrodes, which may be located on the same conductive layer as the multiple conductive lines 30. The orthographic projection of the external electrodes onto the plane of the substrate 10 may be rectangular, circular, or hexagonal, etc. For example, the orthographic projection of the external electrodes onto the plane of the substrate 10 may be a square. The multiple external electrodes may include at least a first external electrode 45, a second external electrode 46, a third external electrode 47, and a fourth external electrode 48. The first external electrode 45, the second external electrode 46, the third external electrode 47, and the fourth external electrode 48 may be located at the four corners of the substrate 10, respectively.

[0045] The first conductive line 31 may include a first segment 31-1 and a second segment 31-2 connected to each other. The first segment 31-1 extends along a second direction Y, and the second segment 31-2 extends along a first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the first segment 31-1 is connected to the first external electrode 45, and the second end of the first segment 31-1 is connected to the second end of the second segment 31-2. The first end of the second segment 31-2 is connected to one end of a second bridge arm. One end of the first bridge arm is connected to the middle portion of the second segment 31-2. In this embodiment, the middle portion of a segment refers to the portion other than the first and second ends. The orthographic projection of the second segment 31-2 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the beam structure 23 onto the plane of the substrate 10, while the orthographic projection of the first segment 31-1 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0046] The second conductive line 32 may include a third segment 32-3 and a fourth segment 32-4 connected to each other. The third segment 32-3 extends along the second direction Y, and the fourth segment 32-4 extends along the first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the third segment 32-3 is connected to the second external electrode 46, and the second end of the third segment 32-3 is connected to the second end of the fourth segment 32-4. The first end of the fourth segment 32-4 is connected to the other end of the second bridge arm. One end of the fourth bridge arm is connected to the middle of the fourth segment 32-4. The orthographic projection of the fourth segment 32-4 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the beam structure 23 onto the plane of the substrate 10. The orthographic projection of the third segment 32-3 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0047] The third conductive line 33 may include a fifth segment 33-5 and a sixth segment 33-6 connected to each other. The fifth segment 33-5 extends along the second direction Y, and the sixth segment 33-6 extends along the first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the fifth segment 33-5 is connected to the third external electrode 47, and the second end of the fifth segment 33-5 is connected to the second end of the sixth segment 33-6. The first end of the sixth segment 33-6 is connected to one end of the third bridge arm. The other end of the fourth bridge arm is connected to the middle of the sixth segment 33-6. The orthographic projection of the sixth segment 33-6 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the beam structure 23 onto the plane of the substrate 10. The orthographic projection of the fifth segment 33-5 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0048] The fourth conductive line 34 may include a seventh segment 34-7 and an eighth segment 34-8 connected to each other. The seventh segment 34-7 extends along the second direction Y, and the eighth segment 34-8 extends along the first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the seventh segment 34-7 is connected to the fourth external electrode 48, and the second end of the seventh segment 34-7 is connected to the second end of the eighth segment 34-8. The first end of the eighth segment 34-8 is connected to the other end of the third bridge arm. The other end of the first bridge arm is connected to the middle of the eighth segment 34-8. The orthographic projection of the eighth segment 34-8 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the beam structure 23 onto the plane of the substrate 10, while the orthographic projection of the seventh segment 34-7 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0049] Figure 2A for Figure 1A A cross-sectional view at point AA in the diagram. Figure 2B for Figure 1A Cross-sectional view of the area marked BB. Figure 2C for Figure 1A A cross-sectional view at the point marked CC. (See diagram below.) Figure 2A , Figure 2B as well as Figure 2C As shown, in this embodiment of the disclosure, a third direction Z is defined, and the third direction Z is perpendicular to the plane formed by the first direction X and the second direction Y. Figure 2A , Figure 2C As shown, the pressure sensor may further include at least one limiting platform 24. For example, the pressure sensor may include two limiting platforms 24, located on opposite sides of the beam-like structure 23 along the second direction Y, and situated between two island-like structures 22 distributed along the first direction X. The orthographic projection of the limiting platform 24 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam-like structure 23 onto the plane of the substrate 10. For example, the orthographic projection of the limiting platform 24 onto the plane of the substrate 10 may be an elongated strip extending along the second direction Y. The limiting platform 24 may include a first end and a second end disposed opposite to each other. The first end may be connected to the substrate 10, and the second end may be a free end. The orthographic projection of the limiting platform 24 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the pressure-sensitive membrane 21 onto the plane of the substrate 10. In this embodiment, the limiting platform prevents damage to the pressure-sensitive membrane due to excessive deformation under high pressure or acceleration impact, thus extending the service life of the pressure sensor.

[0050] like Figure 2A , Figure 2B as well as Figure 2CAs shown, the substrate 10 may further include a cavity 25, a release channel 26, and a back cavity 27. The substrate 10 includes a first surface and a second surface disposed opposite to each other. The back cavity 27 is recessed from the second surface toward the first surface. The release channel 26 is located between the cavity 25 and the back cavity 27. The cavity 25 is closer to the pressure-sensing membrane 21 than the back cavity 27, and the cavity 25 and the back cavity 27 are connected via the release channel 26. In this embodiment, the back cavity 27 can conduct the air pressure on the back of the pressure sensor and facilitate overall pressure measurement. The release channel 26 allows the pressure-sensing component 20 to undergo free displacement deformation under differential pressure. Furthermore, the release channel 26, as an airflow buffer channel, connects the cavity 25 to the external air pressure and can regulate the air pressure in the back cavity 27. In addition, the release channel 26 can separate the suspension island 22-7 and the suspension beam 23-3 from the substrate 10, allowing the pressure-sensing component 20 to undergo free displacement deformation under differential pressure.

[0051] In some exemplary embodiments, such as Figure 2A As shown, the island structure 22 may include islands 22-5, island connecting portions 22-6, and suspended islands 22-7 connected sequentially along a third direction Z. Island 22-5 is connected to the pressure-sensitive membrane 21, and suspended island 22-7 is farther away from the pressure-sensitive membrane 21 than island 22-5. The orthographic projection of suspended island 22-7 onto the plane of substrate 10 includes the orthographic projection of island 22-5 onto the plane of substrate 10. For example, the orthographic projection area of ​​suspended island 22-7 onto the plane of substrate 10 is larger than the orthographic projection area of ​​island 22-5 onto the plane of substrate 10. The orthographic projection of the suspended island 22-7 onto the plane of the substrate 10 includes the orthographic projection of the island connection portion 22-6 onto the plane of the substrate 10. For example, the orthographic projection area of ​​the suspended island 22-7 onto the plane of the substrate 10 is greater than the orthographic projection area of ​​the island connection portion 22-6 onto the plane of the substrate 10, or the orthographic projection area of ​​the suspended island 22-7 onto the plane of the substrate 10 is equal to the orthographic projection area of ​​the island connection portion 22-6 onto the plane of the substrate 10. In this embodiment, by designing the island 22-5, the area in the pressure-sensing component 20 that is not easily deformed can be increased, the overall deformation can be reduced, and the linearity can be improved. The layout of the island 22-5 can change the overall stress distribution of the pressure-sensing component 20. The beam-like structure 23 may include multiple stress concentration areas, such as... Figure 2BAs shown, the beam-like structure 23 may include a first stress concentration region A1, a second stress concentration region A2, a third stress concentration region A3, and a fourth stress concentration region A4. The first piezoresistive element 51, the second piezoresistive element 52, the third piezoresistive element 53, and the fourth piezoresistive element 54 may be located in different stress concentration regions, which can improve the sensitivity of the pressure sensor. For example, the first piezoresistive element 51 is located in the first stress concentration region A1, the second piezoresistive element 52 is located in the second stress concentration region A2, the third piezoresistive element 53 is located in the third stress concentration region A3, and the fourth piezoresistive element 54 is located in the fourth stress concentration region A4. For example, the first bridge arm, the second bridge arm, the third bridge arm, and the fourth bridge arm may be located in different stress concentration regions. In this embodiment, by designing the island connection portion 22-6, the overall thickness of the island-like structure 22 can be increased, which can reduce deformation and improve the linearity of the overall pressure sensor structure. In this embodiment of the disclosure, the design of the suspended island 22-7 not only enhances the structural stability and linearity, but also serves as an airflow buffer structure, which can reduce the impact of airflow on the cavity 25 when the pressure changes, and prevent the phenomenon of airflow overshoot peak.

[0052] In some exemplary embodiments, such as Figure 2CAs shown, the beam-like structure 23 may include a beam body 23-1, a beam connection portion 23-2, and a suspension beam 23-3 connected sequentially along a third direction Z. The beam body 23-1 is connected to the pressure-sensitive membrane 21, and the suspension beam 23-3 is farther away from the pressure-sensitive membrane 21 than the beam body 23-1. The orthographic projection of the suspension beam 23-3 onto the plane of the substrate 10 includes the orthographic projection of the beam body 23-1 onto the plane of the substrate 10. For example, the orthographic projection area of ​​the suspension beam 23-3 onto the plane of the substrate 10 is larger than the orthographic projection area of ​​the beam body 23-1 onto the plane of the substrate 10. The orthographic projection of the suspension beam 23-3 onto the plane of the substrate 10 includes the orthographic projection of the beam connection portion 23-2 onto the plane of the substrate 10. For example, the orthographic projection area of ​​the suspension beam 23-3 onto the plane of the substrate 10 is greater than the orthographic projection area of ​​the beam connection portion 23-2 onto the plane of the substrate 10, or the orthographic projection area of ​​the suspension beam 23-3 onto the plane of the substrate 10 is equal to the orthographic projection area of ​​the beam connection portion 23-2 onto the plane of the substrate 10. In this embodiment, the beam 23-1 not only serves as a stress transmission medium but also concentrates the main stress causing deformation of the pressure-sensing component 20 onto the beam 23-1, thereby improving the sensitivity of the pressure sensor. Furthermore, the beam 23-1 supports the pressure-sensing membrane 21, limits deformation, and enhances linearity. In this embodiment, by providing the beam connection portion 23-2, the overall thickness of the beam structure 23 is increased, the deformation is reduced, and the linearity of the overall structure is improved. In this embodiment of the disclosure, by designing the suspension beam 23-3, in addition to enhancing the structural stability and linearity, the suspension beam 23-3 can also serve as an airflow buffer structure, which can reduce the impact of airflow on the cavity 25 when the pressure changes, and prevent the phenomenon of airflow overshoot peak.

[0053] In some exemplary embodiments, along the third direction Z, the pressure-sensitive diaphragm 21 has a maximum thickness H1, the island structure 22 has a minimum thickness H2, and the beam structure 23 has a minimum thickness H3, where H3 is greater than H1 and H2 is greater than H1. In this embodiment, by setting the island structure 22 and the beam structure 23, the deformation of the pressure sensor can be reduced, and the linearity of the overall structure can be improved. The structure of the pressure sensor is illustrated below with an example of the fabrication process of the pressure sensor. Figure 1A , Figure 1B Take the pressure sensor shown as an example.

[0054] The fabrication process of a pressure sensor may include the following steps: (01) Forming a well array pattern. Forming a well array pattern may include: using photolithography on the substrate 10a to form a well array pattern 60, such as... Figure 3A As shown, Figure 3AThis is a cross-sectional view along the AA direction showing the formation of a well array pattern for a pressure sensor. The well array pattern 60 may include multiple wells 61, within which the substrate 10a is etched away. The wells 61 are used to form a pressure-sensitive film and cavities in subsequent processes. For example, the substrate 10a may be made of monocrystalline silicon. The substrate 10a includes a first surface and a second surface disposed opposite each other, with the wells 61 recessed from the first surface toward the second surface. The substrate 10a is used to form a substrate, a pressure-sensitive film, an island structure, and a beam structure in subsequent processes.

[0055] In some exemplary embodiments, the shape of the orthographic projection of well 61 onto the plane containing base 10a can be circular or polygonal. For example, the polygon can be square, rectangle, hexagon, etc. Multiple wells 61 can be arranged in a square array, such as... Figure 4A , Figure 4B As shown. Alternatively, the four wells 61 are arranged in a parallelogram, and the multiple parallelograms are arranged in a square array, as shown. Figure 4C As shown.

[0056] (02) Forming a pressure-sensitive film and a cavity. Forming the pressure-sensitive film and the cavity may include: subjecting the substrate 10a of the well array pattern 60 to high-temperature annealing, which can promote the migration of silicon atoms on the surface, so that the bottoms of the multiple wells 61 merge and the tops of the wells are closed to form a pressure-sensitive film 21 and a cavity 25, such as Figure 3B As shown, Figure 3B A cross-sectional schematic diagram along the AA direction showing the formation of the pressure-sensing diaphragm and cavity for the pressure sensor.

[0057] (03) Forming a Wheatstone bridge. Forming a Wheatstone bridge may include: forming a plurality of lightly doped piezoresistive elements 50 and a plurality of heavily doped conductive connecting electrodes 40 in the stress concentration region of the beam-shaped structure 23 by photolithography, ion implantation and high-temperature annealing processes. The plurality of piezoresistive elements 50 may include at least a first piezoresistive element 51, a second piezoresistive element 52, a third piezoresistive element 53 and a fourth piezoresistive element 54. The plurality of connecting electrodes 40 may include at least a first connecting electrode 41, a second connecting electrode 42, a third connecting electrode 43 and a fourth connecting electrode 44.

[0058] Subsequently, multiple conductive lines 30 are formed, which may include at least a first conductive line 31, a second conductive line 32, a third conductive line 33, and a fourth conductive line 34. Ohmic contacts are formed between the conductive lines 30 and the connecting electrodes 40, and the multiple piezoresistive elements 50, the multiple connecting electrodes 40, and the multiple conductive lines 30 together form a Wheatstone bridge, such as... Figure 3C As shown, Figure 3C A cross-sectional view along the BB direction showing the formation of a Wheatstone bridge for the pressure sensor.

[0059] In some exemplary embodiments, the material of the conductive wire 30 may include metallic materials. The metallic material may be any one or more of silver (Ag), copper (Cu), aluminum (Al) and molybdenum (Mo), or alloys of the above metals, such as aluminum-neodymium alloy (AlNd) or molybdenum-niobium alloy (MoNb), and may be a single-layer structure or a multi-layer composite structure, such as Mo / Cu / Mo.

[0060] (04) Forming etching trenches. Forming etching trenches may include etching the substrate 10a from one side of the second surface of the substrate 10a to form a plurality of etching trenches 70, such as... Figure 3D As shown, Figure 3D This is a cross-sectional view along the AA direction of the etching groove formed for the pressure sensor. The substrate 10a located within the etching groove 70 is etched away. The etching groove 70 is not connected to the cavity 25. The etching groove 70 and the subsequently formed release channel 26 are arranged in pairs.

[0061] (05) Forming release channels. Forming multiple release channels may include etching the substrate 10a based on the etching groove 70 to form release channels 26, back cavities 27, island structures 22, and beam structures 23, as described above. Figure 2A , Figure 2B as well as Figure 2C As shown.

[0062] Figure 5A This is a top view schematic diagram of a pressure sensor according to another embodiment of the present disclosure. Figure 5B This is a bottom view schematic diagram of a pressure sensor according to another embodiment of the present disclosure. Figure 6A for Figure 5A A cross-sectional view at point AA in the diagram. Figure 6B for Figure 5A Cross-sectional view of the area marked BB. Figure 6C for Figure 5A A cross-sectional view at the point marked CC. (See diagram below.) Figure 5A , Figure 5B , Figure 6A , Figure 6B as well as Figure 6CAs shown, the main structure of the pressure sensor in this embodiment is the same as that in the previous embodiment. The main difference is that the distance L between two adjacent island structures 22 on the same side of the beam structure 23 along the first direction X is reduced. Therefore, a limiting platform is not required, saving space for the pressure sensor. In this embodiment, the stress on the beam structure 23 located between the first island structure 22-1 and the second island structure 22-2 is more concentrated, improving the sensitivity of the pressure sensor. Under the same pressure, this pressure sensor structure can reduce the deformation in the central region of the pressure-sensing component, effectively improving linearity. The pressure sensor provided in this embodiment can be applied to application scenarios where the deformation requirements under overload or impact are relatively relaxed, but high sensitivity and high linearity are required.

[0063] Figure 7A This is a top view schematic diagram of a pressure sensor according to yet another embodiment of the present disclosure. Figure 7B This is a bottom view schematic diagram of a pressure sensor according to yet another embodiment of this disclosure. Figure 7A , Figure 7B As shown, the pressure sensor may include a substrate 10 and a pressure-sensing component 20 connected to the substrate 10. The pressure-sensing component 20 may include a pressure-sensing membrane 21, multiple island structures 22, and a beam structure 23, with the multiple island structures 22 all connected to the beam structure 23. For example, the pressure-sensing component 20 may include two island structures 22, which may be a first island structure 22-1 and a second island structure 22-2, respectively. The orthographic projection of the island structure 22 onto the plane of the substrate 10 may be rectangular, and the orthographic projection of the beam structure 23 onto the plane of the substrate 10 may be a long strip extending along a first direction X. The two island structures 22 may be located on opposite sides of the beam structure 23 along a second direction Y, and the two island structures 22 may be symmetrically arranged about the beam structure 23. Figure 7AAs shown, the pressure sensor may further include multiple conductive lines 30, multiple connecting electrodes 40, and multiple piezoresistive elements 50. For example, the multiple conductive lines 30 may include at least a first conductive line 31, a second conductive line 32, a third conductive line 33, and a fourth conductive line 34, and all of the multiple conductive lines 30 are located on the side of the pressure-sensing component 20 away from the substrate 10. The multiple connecting electrodes 40 may include at least a first connecting electrode 41, a second connecting electrode 42, a third connecting electrode 43, and a fourth connecting electrode 44. The multiple piezoresistive elements 50 may include at least a first piezoresistive element 51, a second piezoresistive element 52, a third piezoresistive element 53, and a fourth piezoresistive element 54. A portion of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 may be embedded within the beam-like structure 23, and the beam-like structure 23 exposes at least a portion of the surface of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 on the side away from the substrate 10. The first piezoresistive element 51, the second piezoresistive element 52, the third piezoresistive element 53, and the fourth piezoresistive element 54 can be located on both sides of the plurality of island structures 22 along the first direction X, and the first piezoresistive element 51, the second piezoresistive element 52, the third piezoresistive element 53, and the fourth piezoresistive element 54 are arranged sequentially at intervals along the first direction X. The pressure sensor of this embodiment can reduce the deformation of the central region of the pressure-sensing component under the same pressure, and can improve linearity. This pressure sensor is applicable to application scenarios that require high linearity and where the area of ​​the pressure-sensing diaphragm is limited and cannot accommodate four silicon islands.

[0064] Figure 8A This is a top view schematic diagram of a pressure sensor according to another embodiment of the present disclosure. Figure 8B This is a bottom view schematic diagram of a pressure sensor according to another embodiment of the present disclosure. Figure 8A , Figure 8BAs shown, the pressure sensor may include a substrate 10 and a pressure-sensing component 20 connected to the substrate 10. The pressure-sensing component 20 may include a pressure-sensing membrane 21, an island-shaped structure 22, and multiple beam-shaped structures 23, with the island-shaped structure 22 connected to the multiple beam-shaped structures 23. The multiple beam-shaped structures 23 may be distributed around the island-shaped structure 22. The orthographic projection of the island-shaped structure 22 onto the plane of the substrate 10 may be rectangular, and the orthographic projection of the beam-shaped structures 23 onto the plane of the substrate 10 may be elongated. The center of the orthographic projection of the island-shaped structure 22 onto the plane of the substrate 10 may coincide with the center of the orthographic projection of the pressure-sensing membrane 21 onto the plane of the substrate 10. The beam-shaped structures 23 may include a first end and a second end disposed opposite to each other, the first end of which may be connected to the island-shaped structure 22, and the second end of which may be connected to the substrate 10. The plurality of beam-like structures 23 may include a first beam-like structure 231, a second beam-like structure 232, a third beam-like structure 233, and a fourth beam-like structure 234, which are distributed around the island-like structure 22. The pressure-sensitive membrane 21 may include a first portion 21-1, a second portion 21-2, a third portion 21-3, and a fourth portion 21-4 spaced apart, which are distributed around the island-like structure 22.

[0065] like Figure 8AAs shown, the pressure sensor may further include multiple conductive lines 30, multiple connecting electrodes 40, and multiple piezoresistive elements 50. For example, the multiple conductive lines 30 may include at least a first conductive line 31, a second conductive line 32, a third conductive line 33, and a fourth conductive line 34, and all of the multiple conductive lines 30 are located on the side of the pressure-sensing component 20 away from the substrate 10. The multiple connecting electrodes 40 may include at least a first connecting electrode 41, a second connecting electrode 42, a third connecting electrode 43, and a fourth connecting electrode 44. The multiple piezoresistive elements 50 may include at least a first piezoresistive element 51, a second piezoresistive element 52, a third piezoresistive element 53, and a fourth piezoresistive element 54. A portion of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 may be embedded within the beam-like structure 23, and the beam-like structure 23 exposes at least a portion of the surface of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 on the side away from the substrate 10. The first piezoresistive element 51 may be located at the second end of the first beam-like structure 231. The second piezoresistive element 52 may be located at the second end of the second beam-like structure 232. The third piezoresistive element 53 can be located at the second end of the third beam-shaped structure 233. The fourth piezoresistive element 54 can be located at the second end of the fourth beam-shaped structure 234. In this embodiment, the multiple beam-shaped structures 23 can concentrate the overall deformation stress of the pressure-sensing component 20 onto the beam-shaped structure 23, improving the sensitivity of the pressure sensor and reducing the overall deformation of the pressure sensor, thereby enhancing the linearity of the pressure sensor. Designing the island-shaped structure 22 at the center of the pressure-sensing diaphragm 21 increases the area of ​​the pressure-sensing component 20 that is not easily deformed, effectively improving the linearity. The pressure sensor of this embodiment is applicable to scenarios where the pressure-sensing diaphragm is thin, has a large area, and has high requirements for linearity.

[0066] In some exemplary embodiments, such as Figure 8A As shown, the island structure 22 has a first central axis O extending along a first direction X and a second central axis P extending along a second direction Y. Multiple beam structures 23 can be symmetrical along the first central axis O and the second central axis P. Both the first central axis O and the second central axis P pass through the center of the island structure 22. In this embodiment, the symmetrical design of the multiple beam structures 23 facilitates the extraction of conductive lines and reduces asymmetry errors.

[0067] In some exemplary embodiments, such as Figure 8AAs shown, the first piezoresistive element 51 may include two oppositely disposed ends. One end of the first piezoresistive element 51 may be connected to the first conductive line 31 via a first connecting electrode 41, and the other end of the first piezoresistive element 51 may be connected to the fourth conductive line 34 via another first connecting electrode 41. The second piezoresistive element 52 may include two oppositely disposed ends. One end of the second piezoresistive element 52 may be connected to the first conductive line 31 via a second connecting electrode 42, and the other end of the second piezoresistive element 52 may be connected to the second conductive line 32 via another second connecting electrode 42. The third piezoresistive element 53 may include two oppositely disposed ends. One end of the third piezoresistive element 53 may be connected to the third conductive line 33 via a third connecting electrode 43, and the other end of the third piezoresistive element 53 may be connected to the fourth conductive line 34 via another third connecting electrode 43. The fourth piezoresistive element 54 may include two oppositely disposed ends. One end of the fourth piezoresistive element 54 may be connected to the second conductive line 32 via a fourth connecting electrode 44, and the other end of the fourth piezoresistive element 54 may be connected to the third conductive line 33 via another fourth connecting electrode 44. In this embodiment of the disclosure, multiple conductive lines 30, multiple connecting electrodes 40, and multiple piezoresistive elements 50 can form a Wheatstone bridge.

[0068] In some exemplary embodiments, such as Figure 8A As shown, the first conductive line 31 may include a first segment 31-1 and a second segment 31-2 connected to each other. The first segment 31-1 extends along the second direction Y, and the second segment 31-2 extends along the first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the first segment 31-1 and the first end of the second segment 31-2 are both connected to the first external electrode 45. The second end of the first segment 31-1 is connected to one end of the first bridge arm, and the second end of the second segment 31-2 is connected to one end of the second bridge arm. The orthographic projection of the second segment 31-2 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10, and the orthographic projection of the first segment 31-1 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0069] The second conductive line 32 may include a third segment 32-3 and a fourth segment 32-4 connected to each other. The third segment 32-3 extends along the second direction Y, and the fourth segment 32-4 extends along the first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the third segment 32-3 and the first end of the fourth segment 32-4 are both connected to the second external electrode 46. The second end of the third segment 32-3 is connected to one end of the fourth bridge arm, and the second end of the fourth segment 32-4 is connected to the other end of the second bridge arm. The orthographic projection of the fourth segment 32-4 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10, and the orthographic projection of the third segment 32-3 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0070] The third conductive line 33 may include a fifth segment 33-5 and a sixth segment 33-6 connected to each other. The fifth segment 33-5 extends along the second direction Y, and the sixth segment 33-6 extends along the first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the fifth segment 33-5 and the first end of the sixth segment 33-6 are both connected to the third external electrode 47. The second end of the fifth segment 33-5 is connected to the other end of the fourth bridge arm, and the second end of the sixth segment 33-6 is connected to one end of the third bridge arm. The orthographic projection of the sixth segment 33-6 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10, and the orthographic projection of the fifth segment 33-5 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0071] The fourth conductive line 34 may include a seventh segment 34-7 and an eighth segment 34-8 connected to each other. The seventh segment 34-7 extends along the second direction Y, and the eighth segment 34-8 extends along the first direction X. Each segment includes a first end and a second end disposed opposite to each other. The first end of the seventh segment 34-7 and the first end of the eighth segment 34-8 are both connected to the fourth external electrode 48. The second end of the seventh segment 34-7 is connected to the other end of the first bridge arm, and the second end of the eighth segment 34-8 is connected to the other end of the third bridge arm. The orthographic projection of the eighth segment 34-8 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10, and the orthographic projection of the seventh segment 34-7 onto the plane of the substrate 10 does not overlap with the orthographic projection of the beam structure 23 onto the plane of the substrate 10.

[0072] Figure 9A This is a top view schematic diagram of a pressure sensor according to another embodiment of the present disclosure. Figure 9B This is a bottom view schematic diagram of a pressure sensor according to another embodiment of the present disclosure. Figure 9C for Figure 9A A cross-sectional view at the point marked DD. (See diagram below.) Figure 9A , Figure 9B as well as Figure 9C As shown, the pressure sensor may include a substrate 10 and a pressure-sensing component 20 connected to the substrate 10. The pressure-sensing component 20 may include a pressure-sensing diaphragm 21 and an island-shaped structure 22. The orthographic projection of the island-shaped structure 22 onto the plane of the substrate 10 may be cross-shaped. The pressure-sensing diaphragm 21 is disposed around the island-shaped structure 22, and the center of the orthographic projection of the pressure-sensing diaphragm 21 onto the plane of the substrate 10 coincides with the center of the orthographic projection of the island-shaped structure 22 onto the plane of the substrate 10.

[0073] The pressure sensor may further include multiple conductive lines 30, multiple connecting electrodes 40, and multiple piezoresistive elements 50. For example, the multiple conductive lines 30 may include at least a first conductive line 31, a second conductive line 32, a third conductive line 33, and a fourth conductive line 34, and all of the multiple conductive lines 30 are located on the side of the pressure-sensing component 20 away from the substrate 10. The multiple connecting electrodes 40 may include at least a first connecting electrode 41, a second connecting electrode 42, a third connecting electrode 43, and a fourth connecting electrode 44. The multiple piezoresistive elements 50 may include at least a first piezoresistive element 51, a second piezoresistive element 52, a third piezoresistive element 53, and a fourth piezoresistive element 54. A portion of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 may be embedded within the pressure-sensing membrane 21 or the substrate 10, and at least a portion of the surface of the pressure-sensing membrane 21 or the substrate 10 exposed on the side of the multiple connecting electrodes 40 and the multiple piezoresistive elements 50 away from the substrate 10 may be exposed.

[0074] The orthographic projection of the first piezoresistive element 51 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the pressure-sensitive film 21 onto the plane of the substrate 10. For example, the orthographic projection of the first piezoresistive element 51 onto the plane of the substrate 10 lies within the orthographic projection of the pressure-sensitive film 21 onto the plane of the substrate 10. The orthographic projection of the second piezoresistive element 52 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the pressure-sensitive film 21 onto the plane of the substrate 10. For example, the orthographic projection of the second piezoresistive element 52 onto the plane of the substrate 10 lies within the orthographic projection of the pressure-sensitive film 21 onto the plane of the substrate 10. The orthographic projection of the third piezoresistive element 53 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the pressure-sensitive film 21 onto the plane of the substrate 10. For example, the orthographic projection of the third piezoresistive element 53 onto the plane of the substrate 10 lies within the orthographic projection of the pressure-sensitive film 21 onto the plane of the substrate 10. The orthographic projection of the fourth piezoresistive element 54 onto the plane of the substrate 10 at least partially overlaps with the orthographic projection of the pressure-sensitive membrane 21 onto the plane of the substrate 10. For example, the orthographic projection of the fourth piezoresistive element 54 onto the plane of the substrate 10 lies within the orthographic projection of the pressure-sensitive membrane 21 onto the plane of the substrate 10. In this embodiment, the island structure 22 is designed in a cross shape, and at least a portion of the pressure assembly 50 is disposed on the pressure-sensitive membrane 21, effectively improving the sensitivity of the pressure sensor. The cross-shaped island structure 22 has the advantages of occupying a smaller area, reducing deformation, and improving linearity. Furthermore, this pressure sensor facilitates the lead-out of conductive wires and can reduce asymmetric errors. The pressure sensor provided in this embodiment is applicable to applications where the pressure-sensitive membrane is small in size but still requires high linearity, and where the requirements for shock resistance and overload resistance are relatively tolerant.

[0075] In some exemplary embodiments, such as Figure 9A As shown, the island structure 22 has a first central axis O extending along a first direction X and a second central axis P extending along a second direction Y. Both the first central axis O and the second central axis P pass through the center of the island structure 22. The island structure 22 can be symmetrical along the first central axis O and along the second central axis P. In this embodiment of the disclosure, the island structure 22 is designed symmetrically to reduce asymmetry errors.

[0076] In some exemplary embodiments, such as Figure 9A As shown, the first piezoresistive element 51, the second piezoresistive element 52, the third piezoresistive element 53 and the fourth piezoresistive element 54 can be symmetrical along the first central axis O and along the second central axis P. In this embodiment of the present disclosure, the multiple piezoresistive elements 50 are designed symmetrically to reduce asymmetric errors.

[0077] This disclosure provides a method for fabricating a pressure sensor, the method comprising: The substrate is etched to form a well array pattern, the well array pattern including multiple wells, the wells being recessed from the first surface toward the second surface, and the substrate located within the wells is etched away; The wells are subjected to high-temperature annealing to form the pressure-sensitive membrane and cavity. The substrate is etched to form the island-like structure.

[0078] In some exemplary embodiments, etching the substrate to form the island structure includes: The substrate is etched from one side of the second surface of the substrate to form a plurality of etch grooves, the substrate located within the etch grooves is etched away, and the etch grooves are not connected to the cavity; The substrate is etched based on the etching groove to form the back cavity, and the back cavity is connected to the cavity.

[0079] While the embodiments disclosed in this invention have been described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. It should be noted that the above embodiments or implementation methods are merely exemplary and not restrictive. Therefore, this disclosure is not limited to the content specifically shown and described herein. Various modifications, substitutions, or omissions can be made to the form and details of the implementation without departing from the scope of this disclosure.

Claims

1. A pressure sensor, characterized in that, include: The substrate includes a first surface, a second surface, and a back cavity, wherein the first surface and the second surface are disposed opposite to each other, and the back cavity is recessed from the second surface toward the first surface; A pressure-sensitive component is mounted on the substrate and includes a pressure-sensitive film and at least one island structure, wherein the orthographic projection of the island structure onto the plane of the substrate at least partially overlaps with the orthographic projection of the back cavity onto the plane of the substrate, and the back cavity exposes a portion of the island structure. The island structure includes an island, an island connecting portion, and a suspended island arranged sequentially along a direction perpendicular to the plane of the substrate. The island is connected to the pressure-sensitive membrane, and the suspended island is closer to the second surface than the island. The orthographic projections of the island and the suspended island onto the plane of the substrate both include the orthographic projection of the island connecting portion onto the plane of the substrate.

2. The pressure sensor as described in claim 1, characterized in that, The pressure-sensing component further includes at least one beam-shaped structure, and all the island-shaped structures are connected to the beam-shaped structure; the beam-shaped structure includes a beam body, a beam connecting portion, and a suspension beam arranged sequentially along a direction perpendicular to the plane of the substrate, and the beam body is connected to the pressure-sensing membrane, and the suspension beam is closer to the second surface than the beam body; The orthographic projections of the beam and the suspension beam onto the plane of the substrate both include the orthographic projection of the beam connection portion onto the plane of the substrate.

3. The pressure sensor as described in claim 2, characterized in that, The pressure-sensing component includes a beam-shaped structure that extends along a first direction and is connected to the substrate at both ends along the first direction. The pressure-sensing component includes four spaced-apart island structures, which are located on both sides of the beam structure along the second direction, with two island structures distributed on each side; the first direction intersects the second direction and the plane formed by them is parallel to the plane of the substrate.

4. The pressure sensor as described in claim 3, characterized in that, It also includes at least one limiting platform, and the limiting platform is located between the pressure-sensitive membrane and the second surface; the limiting platform extends along the second direction and includes a first end and a second end disposed opposite to each other, and the first end is connected to the substrate, and the second end is a free end; The limiting platform is located between the two island-shaped structures distributed along the first direction, and the orthographic projection of the limiting platform and the beam-shaped structure on the plane where the substrate is located does not overlap.

5. The pressure sensor as described in claim 3, characterized in that, The four island-shaped structures are symmetrically distributed about the beam-shaped structure.

6. The pressure sensor as described in claim 3, characterized in that, It also includes multiple piezoresistive elements, all of which are mounted on the beam-shaped structure; the multiple piezoresistive elements include at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element, and a fourth piezoresistive element, and the first piezoresistive element, the second piezoresistive element, the third piezoresistive element, and the fourth piezoresistive element are arranged at intervals along the first direction; the second piezoresistive element and the third piezoresistive element are located between two island-shaped structures along the first direction, and the first piezoresistive element and the fourth piezoresistive element are respectively located on both sides of the four island-shaped structures along the first direction.

7. The pressure sensor as described in claim 2, characterized in that, The pressure-sensing component includes a beam-shaped structure that extends along a first direction and is connected to the substrate at both ends along the first direction; the pressure-sensing component includes two island-shaped structures that are located on both sides of the beam-shaped structure along a second direction; the first direction and the second direction intersect and form a plane that is parallel to the plane of the substrate.

8. The pressure sensor as described in claim 7, characterized in that, It also includes multiple piezoresistive elements, all of which are mounted on the beam-shaped structure; the multiple piezoresistive elements include at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element, and a fourth piezoresistive element, which are arranged sequentially at intervals along the first direction; the first piezoresistive element and the second piezoresistive element are located on one side of the two island-shaped structures along the first direction, and the third piezoresistive element and the fourth piezoresistive element are located on the other side of the two island-shaped structures along the first direction.

9. The pressure sensor as described in claim 2, characterized in that, The pressure-sensing component includes four beam-shaped structures and one island-shaped structure. The four beam-shaped structures are distributed around the island-shaped structure. Each beam-shaped structure includes a first end and a second end that are disposed opposite to each other. The first end is connected to the island-shaped structure, and the second end is connected to the substrate.

10. The pressure sensor as described in claim 9, characterized in that, The island-like structure has a first central axis extending along a first direction and a second central axis extending along a second direction. The four beam-like structures are symmetrical along the first central axis and the second central axis. The first direction and the second direction intersect and form a plane that is parallel to the plane of the substrate.

11. The pressure sensor as described in claim 9, characterized in that, It also includes multiple piezoresistive elements, which include at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element, and a fourth piezoresistive element, and the first piezoresistive element, the second piezoresistive element, the third piezoresistive element, and the fourth piezoresistive element are respectively installed on different beam-shaped structures.

12. The pressure sensor as claimed in claim 1, characterized in that, The pressure-sensitive component includes an island-shaped structure, and the orthographic projection of the island-shaped structure onto the plane of the substrate is cross-shaped, with the pressure-sensitive membrane surrounding the island-shaped structure.

13. The pressure sensor as described in claim 12, characterized in that, It also includes multiple piezoresistive elements, which include at least a first piezoresistive element, a second piezoresistive element, a third piezoresistive element, and a fourth piezoresistive element. The orthographic projections of the first piezoresistive element, the second piezoresistive element, the third piezoresistive element, and the fourth piezoresistive element on the plane of the substrate at least partially overlap with the orthographic projection of the pressure-sensitive film on the plane of the substrate. All of the multiple piezoresistive elements are mounted on the pressure-sensitive film.

14. The pressure sensor according to any one of claims 1 to 13, characterized in that, The substrate also has a cavity and a release channel, and the cavity, the release channel and the back cavity are arranged sequentially along a direction perpendicular to the plane of the substrate. The cavity and the back cavity are connected through the release channel. The cavity is closer to the pressure-sensitive membrane than the back cavity. The orthographic projection of the island structure onto the plane of the substrate is located within the range of the orthographic projection of the release channel onto the plane of the substrate.

15. A method for manufacturing a pressure sensor, characterized in that, A method for preparing a pressure sensor as described in any one of claims 1 to 14; the preparation method includes: The substrate is etched to form a well array pattern, the well array pattern including multiple wells, the wells being recessed from the first surface toward the second surface, and the substrate located within the wells is etched away; The wells are subjected to high-temperature annealing to form the pressure-sensitive membrane and cavity. The substrate is etched to form the island-like structure.

16. The method for preparing a pressure sensor as described in claim 15, characterized in that, The etching of the substrate to form the island structure includes: The substrate is etched from one side of the second surface of the substrate to form a plurality of etch grooves, the substrate located within the etch grooves is etched away, and the etch grooves are not connected to the cavity; The substrate is etched based on the etching groove to form the back cavity, and the back cavity is connected to the cavity.

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