Pressure sensing chip and manufacturing method therefor, and electronic product

Abstract

A pressure sensing chip, comprising a substrate (101), a support layer (102), a pressure-sensitive structure (104), and a reinforcement layer (105). The substrate (101) comprises a pressure-sensing membrane portion (1011). The support layer (102) is disposed on one side of the substrate (101), a recess (1021) is formed in the surface of the support layer (102) close to the substrate (101), and a pressure cavity (103) is formed between the recess (1021) and the pressure-sensing membrane portion (1011). At least a portion of the pressure-sensitive structure (104) is embedded in the surface of the side of the pressure-sensing membrane portion (1011) close to the support layer (102), and a partial surface of the pressure-sensitive structure (104) is exposed in the pressure cavity (103). The reinforcement layer (105) is disposed on the side of the support layer (102) distant from the substrate (101), and is capable of preventing the support layer (102) above the pressure cavity (103) from being ruptured under pressure. Also provided are a manufacturing method for a pressure sensing chip and an electronic product comprising a pressure sensing chip.

Description

Pressure sensing chip and its fabrication method, electronic products Technical Field

[0001] This disclosure relates to the field of microelectronics technology, and in particular to a pressure sensing chip and its fabrication method, as well as electronic products. Background Technology

[0002] A pressure sensor chip is a chip that can sense pressure signals and convert them into electrical signals. Pressure sensor chips typically consist of a pressure-sensitive structure and a signal processing unit.

[0003] Pressure sensing chips can be classified according to their operating principle into piezoresistive pressure sensing chips, capacitive pressure sensing chips, resonant pressure sensing chips, and piezoelectric pressure sensing chips. Among them, piezoresistive and capacitive pressure sensing chips are widely used in the automotive, industrial control, consumer electronics, construction, and medical fields due to their advantages such as simple manufacturing process, low cost, high reliability, and compatibility with CMOS (complementary metal-oxide-semiconductor) technology. Summary of the Invention

[0004] On one hand, a pressure sensing chip is provided. The pressure sensing chip includes a substrate, a support layer, a pressure-sensitive structure, and a reinforcing layer; the substrate includes a pressure-sensitive diaphragm; the support layer is disposed on one side of the substrate, and a groove is formed on the surface of the support layer near the substrate, forming a pressure cavity between the groove and the pressure-sensitive diaphragm; at least a portion of the pressure-sensitive structure is embedded on the surface of the pressure-sensitive diaphragm near the support layer, and a portion of the surface of the pressure-sensitive structure is exposed in the pressure cavity; the reinforcing layer is disposed on the side of the support layer away from the substrate.

[0005] In some embodiments, the pressure sensing chip further includes a reinforcing structure located within the pressure chamber and connected to the bottom wall of the groove; the orthographic projection of the reinforcing structure on the substrate does not overlap with the orthographic projection of the pressure-sensitive structure on the substrate.

[0006] In some embodiments, the side surface of the reinforcing structure near the pressure-sensitive membrane is spaced apart from the pressure-sensitive membrane; or, the side surface of the reinforcing structure near the pressure-sensitive membrane is connected to the pressure-sensitive membrane.

[0007] In some embodiments, the reinforcing structure is disposed at a distance from the pressure-sensing diaphragm on the side surface near the pressure-sensing diaphragm, and the distance between the reinforcing structure and the substrate along the thickness direction of the substrate is 1 to 2 times the distance by which the pressure-sensing diaphragm deforms when the pressure sensing chip is subjected to full-scale pressure.

[0008] In some embodiments, the side surface of the reinforcing structure near the pressure-sensitive membrane is connected to the pressure-sensitive membrane, and the location where the side surface of the reinforcing structure near the pressure-sensitive membrane is connected to the pressure-sensitive membrane includes a right angle.

[0009] In some embodiments, the centerline of the pressure-sensitive diaphragm extends through the reinforcing structure along the thickness direction of the substrate.

[0010] In some embodiments, the reinforcing structure and the support layer are integrally formed.

[0011] In some embodiments, the pressure-sensitive structure includes a first capacitor, which includes a first electrode plate and a second electrode plate disposed opposite to each other; the first electrode plate is embedded on the side surface of the pressure-sensitive membrane portion near the support layer, and the side surface of the first electrode plate away from the pressure-sensitive membrane portion is exposed in the pressure chamber; the second electrode plate is disposed on the bottom wall of the groove.

[0012] In some embodiments, the pressure-sensitive structure further includes a second capacitor, which includes a third electrode plate and a fourth electrode plate disposed opposite to each other; the third electrode plate is embedded on the side surface of the pressure-sensitive membrane portion near the support layer, and the side surface of the third electrode plate away from the pressure-sensitive membrane portion is exposed in the pressure chamber; the fourth electrode plate is disposed on the bottom wall of the groove; wherein the orthographic projection of the first capacitor on the substrate and the orthographic projection of the second capacitor on the substrate do not overlap; the centerline of the pressure-sensitive membrane portion passes through the first capacitor along the thickness direction of the substrate.

[0013] In some embodiments, the orthographic projection of the second capacitor onto the substrate is disposed around the outer edge of the orthographic projection of the first capacitor onto the substrate.

[0014] In some embodiments, the substrate further includes a body portion disposed around the pressure-sensing diaphragm portion; a pressure channel is disposed within the pressure sensing chip, the pressure channel including a first portion and a second portion connected to each other; the first portion penetrates through a portion of the body portion and a support layer, the second portion is disposed within the support layer and located between the pressure cavity and the reinforcing layer; the orthographic projection of the second portion on the substrate covers the orthographic projection of the pressure cavity on the substrate.

[0015] In some embodiments, the pressure-sensitive structure includes a plurality of pressure-sensitive resistors, which are embedded on the side surface of the pressure-sensitive diaphragm near the support layer.

[0016] In some embodiments, a reference pressure cavity is further provided within the support layer, the reference pressure cavity being located on the side of the pressure cavity away from the substrate; the pressure sensing chip further includes a reference pressure-sensitive structure, a portion of the surface of the reference pressure-sensitive structure being exposed within the reference pressure cavity, and the reference pressure-sensitive structure being configured to have the same structural type as the pressure-sensitive structure.

[0017] In some embodiments, the pressure-sensitive structure includes a first capacitor, and the reference pressure-sensitive structure includes a reference capacitor; the reference capacitor includes a first reference plate and a second reference plate disposed opposite to each other; the first reference plate is disposed on the surface of the reference pressure chamber away from the substrate, and the second reference plate is embedded in a support layer on the side of the reference pressure chamber close to the substrate, and the surface of the second reference plate away from the substrate is exposed in the reference pressure chamber.

[0018] In some embodiments, the pressure-sensitive structure includes a pressure-sensitive resistor, and the reference pressure-sensitive structure includes a reference resistor. The reference resistor is embedded in a support layer on the side of the reference pressure chamber closest to the substrate, and the surface of the reference resistor on the side furthest from the substrate is exposed in the reference pressure chamber.

[0019] In some embodiments, the substrate further includes a body portion disposed around the pressure-sensitive membrane portion; the thickness of the body portion is greater than the thickness of the pressure-sensitive membrane portion; or, the thickness of the body portion is equal to the thickness of the pressure-sensitive membrane portion.

[0020] In some embodiments, the pressure sensing chip further includes leads, conductive pillars, a redistribution layer, and connectors; the leads are embedded in the support layer and connected to the pressure-sensitive structure; the conductive pillars penetrate at least a portion of the reinforcing layer and the support layer and are connected to the leads; the redistribution layer is disposed on the side of the reinforcing layer away from the substrate and is connected to the conductive pillars; the connectors are connected to the side of the redistribution layer away from the substrate.

[0021] In some embodiments, the material of the support layer includes silicon nitride; and / or, the material of the reinforcing layer includes polycrystalline silicon.

[0022] On the other hand, an electronic product is provided. The electronic product includes a pressure sensing chip and a circuit board as described in any of the above embodiments, wherein the circuit board is connected to the pressure sensing chip.

[0023] In another aspect, a method for fabricating a pressure sensing chip is provided, comprising: providing a substrate, the substrate including a pressure-sensitive membrane portion; forming a support layer on one side of the substrate, a groove is formed on the surface of the support layer near the substrate, a pressure cavity is formed between the groove and the pressure-sensitive membrane portion, at least a portion of a pressure-sensitive structure is embedded on the surface of the pressure-sensitive membrane portion near the support layer, and a portion of the surface of the pressure-sensitive structure is exposed in the pressure cavity; and forming a reinforcing layer on the side of the support layer away from the substrate.

[0024] In some embodiments, forming a support layer on one side of the substrate includes: forming a sacrificial layer that covers at least a portion of a pressure-sensitive structure embedded on the side surface of the pressure-sensitive diaphragm near the support layer; forming a support film that covers the sacrificial layer; forming at least one through-hole in the portion of the support film covering the sacrificial layer that exposes the sacrificial layer; removing the sacrificial layer through the through-hole to form a groove; and filling the through-hole with an insulating material to form the support layer.

[0025] In some embodiments, the pressure-sensitive structure includes a first capacitor, the first capacitor including a first electrode and a second electrode; before forming the sacrificial layer, the method for fabricating the pressure sensing chip further includes: forming the first electrode of the pressure-sensitive structure on one side of the pressure-sensitive membrane; after forming the sacrificial layer, the method for fabricating the pressure sensing chip further includes: forming the second electrode of the pressure-sensitive structure on the side of the sacrificial layer away from the substrate. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly introduced below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure. Specific specifications and parameters can be designed and adjusted according to product requirements.

[0027] Figure 1 is a cross-sectional view of a front-facing pressure sensing chip according to some embodiments;

[0028] Figure 2 is a cross-sectional view of a back-side pressure sensing chip according to some embodiments;

[0029] Figure 3 is a flowchart illustrating the fabrication steps of a pressure sensing chip according to some embodiments;

[0030] Figures 4 to 9 are cross-sectional views of a pressure sensing chip according to some embodiments;

[0031] Figure 10 is a top view of a reinforcing structure and a pressure-sensitive structure according to some embodiments;

[0032] Figure 11 is a cross-sectional view of another pressure sensing chip according to some embodiments;

[0033] Figure 12 is a top view of a first capacitor and a second capacitor according to some embodiments;

[0034] Figures 13 to 16 are cross-sectional views of another pressure sensing chip according to some embodiments. Detailed Implementation

[0035] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0036] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0037] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0038] In describing some embodiments, the term "connection" and its derivative expressions may be used. For example, the term "connection" may be used in describing some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0039] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0040] The use of “configured as” in this article implies an open and inclusive language that does not exclude the applicability to or configuration of devices to perform additional tasks or steps.

[0041] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable range of deviation for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0042] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on another layer or substrate, or that there is an intermediate layer between the layer or element and another layer or substrate.

[0043] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0044] The pressure sensing chip 100 may include a front pressure sensing chip 1 and a rear pressure sensing chip 1'.

[0045] For example, as shown in FIG1, the front-facing pressure sensing chip 1 includes:

[0046] Glass substrate 1-1, the basic structure of the front pressure sensing chip 1, and other structures used to support the front pressure sensing chip 1.

[0047] The silicon substrate 1-2 is the core structure of the pressure sensing chip 1 on the front side, and is located on one side of the glass substrate 1-1. It is used to carry the resistor 1-6, resistor connection lead 1-7, electrode 1-8 and metal lead 1-9 and other structures.

[0048] Vacuum pressure chamber 1-3 is formed between silicon substrate 1-2 and glass substrate 1-1.

[0049] Pressure-sensitive membrane 1-5, silicon substrate 1-2 includes pressure-sensitive membrane 1-5, pressure-sensitive membrane 1-5 is located on the side of vacuum pressure chamber 1-3 away from glass substrate 1-1, pressure-sensitive membrane 1-5 converts pressure signal into deformation signal.

[0050] Stress concentration structure 1-4 is formed at the connection between the bottom wall and the side wall of the vacuum pressure chamber 1-3.

[0051] Resistor 1-6, resistor connection lead 1-7, electrode 1-8, and metal lead 1-9 are disposed on the side of silicon substrate 1-2 away from glass substrate 1-1. Resistor 1-6 is located on pressure-sensitive membrane 1-5. Resistor 1-6 is connected to resistor connection lead 1-7, resistor connection lead 1-7 is connected to electrode 1-8, electrode 1-8 is connected to metal lead 1-9, and the signal from resistor 1-6 is transmitted to signal processing unit through resistor connection lead 1-7, electrode 1-8, and metal lead 1-9.

[0052] For example, as shown in FIG1, the resistors 1-6 of the front pressure sensing chip 1 are located on the pressure sensing film 1-5 and exposed to the external environment. The resistors 1-6 are easily affected by the external environment, causing performance drift or failure. Therefore, the front pressure sensing chip 1 has poor environmental adaptability and low reliability.

[0053] To improve the environmental adaptability of the pressure sensing chip 100, a back-side pressure sensing chip 1' is proposed. As shown in Figure 2, the back-side pressure sensing chip 1' includes:

[0054] The basic structure of the silicon substrate 1-2' and the back-side pressure sensing chip 1' is used to support other structures of the back-side pressure sensing chip 1'.

[0055] The core structure of the glass substrate 1-1' and the pressure sensing chip 1' on the back is located on one side of the silicon substrate 1-2' and is used to support structures such as metal lead posts 1-10', RDL 1-11' (ReDistribution Layer), UBM 1-12' (Under Ball Metal), and solder balls 1-13'.

[0056] The pressure-sensitive membrane 1-5' and the silicon substrate 1-2' include the pressure-sensitive membrane 1-5', which converts the pressure signal into a deformation signal.

[0057] Vacuum pressure chamber 1-3' is formed between the glass substrate 1-1' and the pressure-sensing membrane 1-5'. The pressure value inside the vacuum pressure chamber 1-3' is the reference pressure for the pressure measured by the back pressure sensing chip 1'. When the external pressure value is equal to the pressure value inside the vacuum pressure chamber 1-3', the output of the back pressure sensing chip 1' is zero. When the external pressure is greater than the pressure inside the vacuum pressure chamber 1-3', the output of the back pressure sensing chip 1' is the external atmospheric pressure minus the pressure inside the pressure chamber.

[0058] Resistor 1-6', at least a portion of which is disposed on pressure-sensitive diaphragm 1-5', and resistor 1-6' converts the deformation signal of pressure-sensitive diaphragm 1-5' into an electrical signal.

[0059] The resistor connection lead 1-7' is an electrical connection structure of the pressure sensing chip 1' on the back side. The resistor connection lead 1-7' is connected to the resistor 1-6', which transmits the electrical signal on the resistor 1-6' to the metal lead post 1-10'.

[0060] The metal lead post 1-10' is an electrical connection structure of the pressure sensing chip 1' on the back side. The metal lead post 1-10' passes through the glass substrate 1-1' and is connected to the resistor connection lead 1-7', transmitting the electrical signal on the resistor connection lead 1-7' to RDL1-11'.

[0061] RDL1-11' is the electrical connection structure of the pressure sensing chip 1' on the back side. RDL1-11' is located on the side of the glass substrate 1-1' away from the silicon substrate 1-2' and is connected to the metal lead post 1-10', transmitting the electrical signal on the metal lead post 1-10' to UBM1-12'.

[0062] UBM1-12' is the electrical connection structure of the back-side pressure sensing chip 1'. UBM1-12' is located on the side of the glass substrate 1-1' away from the silicon substrate 1-2' and is connected to RDL1-11', transmitting the electrical signal on RDL1-11' to the solder ball 1-13'. Furthermore, UBM1-12' is the bonding layer that interconnects RDL1-11' and the solder ball 1-13', preventing the diffusion of material atoms from the solder ball 1-13' to RDL1-11'.

[0063] Solder balls 1-13' are the input and output ports of the pressure sensing chip 1' on the back side. During packaging, they are bonded to the packaging substrate by flip-chip bonding.

[0064] For example, as shown in FIG2, the resistors 1-6' of the back pressure sensing chip 1' are sealed in the vacuum pressure chamber 1-3'. During the use of the back pressure sensing chip 1', the resistors 1-6' will not come into contact with the pressure application medium, which can effectively improve the environmental adaptability and reliability of the back pressure sensing chip 1'.

[0065] Both the front-facing pressure sensor chip 1 and the back-facing pressure sensor chip 1' require two wafers for fabrication.

[0066] For example, when fabricating the back-side pressure sensing chip 1', a resistor 1-6' and a resistor connection lead 1-7' can be formed on one side surface of the silicon substrate 1-2', and the resistor 1-6' and the resistor connection lead 1-7' are connected; and a first groove is formed on the other side surface of the silicon substrate 1-2', and the thinned portion of the silicon substrate 1-2' after the first groove is formed forms a pressure-sensitive film 1-5', at least a portion of the resistor 1-6' is located on the pressure-sensitive film 1-5', and the silicon substrate 1-2' serves as the first wafer.

[0067] Metal lead post 1-10' is formed through the glass substrate 1-1'. RDL1-11' and UBM1-12' are formed on one side surface of the glass substrate 1-1'. RDL1-11' is connected to the metal lead post 1-10'. A solder ball 1-13' is formed on the side of UBM1-12' away from the glass substrate 1-1'. Then, a second groove is opened on the other side surface of the glass substrate 1-1'. The second groove is located between the two metal lead posts 1-10'. The glass substrate 1-1' serves as the second wafer.

[0068] The silicon substrate 1-2' is bonded to the glass substrate 1-1' so that the metal lead post 1-10' contacts the resistor connection lead 1-7'. A vacuum pressure chamber 1-3' is formed between the second groove and the pressure-sensitive film 1-5' of the silicon substrate 1-2'. At least a portion of the resistor 1-6' is located in the vacuum pressure chamber 1-3'.

[0069] The production cost is greatly increased because two wafers are required to fabricate the back-side pressure sensor chip 1'. Furthermore, the process of bonding the two wafers together after fabricating them separately takes a long time, which greatly increases time costs and reduces production efficiency.

[0070] Therefore, in some embodiments, a method for fabricating a pressure sensing chip 100 is provided, as shown in FIG3, including:

[0071] S1. A substrate 101 is provided, the substrate 101 including a pressure-sensitive membrane portion 1011.

[0072] For example, the substrate 101 may be a silicon substrate, and the substrate 101 includes a pressure-sensitive diaphragm portion 1011 and a body portion 1012, the body portion 1012 being disposed around the pressure-sensitive diaphragm portion 1011. The pressure-sensitive diaphragm portion 1011 is used to convert pressure signals into deformation signals.

[0073] For example, the thickness of the body portion 1012 of the substrate 101 can be the same as the thickness of the pressure-sensitive membrane portion 1011, and the thickness of the body portion 1012 can also be greater than the thickness of the pressure-sensitive membrane portion 1011.

[0074] For example, when the thickness of the body portion 1012 is the same as the thickness of the pressure-sensitive film portion 1011, there is no need to etch the substrate 101; when the thickness of the body portion 1012 is greater than the thickness of the pressure-sensitive film portion 1011, silicon nitride can be grown at the bottom of the substrate 101 as a mask layer. After the silicon nitride is deposited, the required shape of the pressure-sensitive film portion 1011 is photolithographically formed on the silicon nitride. Then, the portion of the substrate 101 exposed by the silicon nitride is etched. After the etching is completed, the silicon nitride mask layer is removed, thereby forming a pressure-sensitive film portion 1011 with a thickness less than that of the body portion 1012.

[0075] Exemplarily, the step of etching the substrate 101 to form a pressure-sensitive film portion 1011 with a thickness less than that of the body portion 1012 can be performed immediately after the substrate 101 is provided; it can also be performed last, after all other structures have been fabricated; or it can be performed after some other structures have been fabricated. This disclosure is not limiting. This disclosure describes the process of etching the substrate 101 to form a pressure-sensitive film portion 1011 with a thickness less than that of the body portion 1012 after the formation of the reinforcing layer 105 as an example.

[0076] S2. A support layer 102 is formed on one side of the base 101. A groove 1021 is formed on the surface of the support layer 102 near the base 101. A pressure cavity 103 is formed between the groove 1021 and the pressure-sensitive membrane portion 1011. At least a portion of the pressure-sensitive structure 104 is embedded in the surface of the pressure-sensitive membrane portion 1011 near the support layer 102. A portion of the surface of the pressure-sensitive structure 104 is exposed in the pressure cavity 103.

[0077] For example, the groove 1021 includes a side wall 1021-2 and a bottom wall 1021-1. The side wall 1021-2 is disposed around the bottom wall 1021-1. The side wall 1021-2, the bottom wall 1021-1 and the surface of the pressure-sensitive diaphragm 1011 of the groove 1021 form a closed pressure chamber 103.

[0078] For example, the varistor 104 can be a resistor or a capacitor, and this disclosure does not limit it.

[0079] For example, a portion of the surface of the varistor 104 refers to a portion of the outer surface of the varistor 104; when the varistor 104 is a resistor, a portion of the surface of the varistor 104 refers to the surface of the varistor 104 away from the substrate 101; when the varistor 104 is a capacitor, a portion of the surface of the varistor 104 refers to the surface of the lower plate of the capacitor away from the substrate 101, and the surface of the upper plate of the capacitor other than the surface that contacts the bottom wall 1021-1 of the groove 1021.

[0080] S3. A reinforcing layer 105 is formed on the side of the support layer 102 away from the substrate 101.

[0081] For example, a polycrystalline silicon material can be deposited as a reinforcing layer 105 on the side of the support layer 102 away from the substrate 101 by epitaxial growth. The reinforcing layer 105 can serve as a reinforcing structure for the pressure cavity 103 and can prevent the support layer 102 above the pressure cavity 103 from being crushed and damaging the structure of the pressure cavity 103.

[0082] For example, the thickness of the reinforcing layer 105 can be 100 μm.

[0083] In some embodiments, S2, a support layer 102 is formed on one side of the substrate 101, as shown in FIG3, including:

[0084] S2.1 Forming a sacrificial layer 100-1, the sacrificial layer 100-1 covering at least a portion of the pressure-sensitive structure 104 embedded on the side surface of the pressure-sensitive membrane portion 1011 near the support layer 102.

[0085] For example, a silicon oxide thin film can be deposited on one side of the substrate 101, and the desired morphology can be prepared on the silicon oxide thin film by photolithography and etching to form a sacrificial layer 100-1.

[0086] For example, the sacrificial layer 100-1 needs to cover at least a portion of the pressure-sensitive structure 104 embedded on one side surface of the pressure-sensitive diaphragm 1011, so that at least a portion of the surface of the finally formed pressure-sensitive structure 104 can be exposed in the pressure chamber 103.

[0087] S2.2 Form a support film 102', which covers the sacrificial layer 100-1.

[0088] For example, the material of the support film 102' can be silicon nitride, the support film 102' is laid in a whole layer, and the support film 102' can be polished after deposition.

[0089] S2.3. At least one through hole 102-1' is formed in the portion of the supporting film 102' covering the sacrificial layer 100-1, and the through hole 102-1' exposes the sacrificial layer 100-1.

[0090] For example, a via 102-1' can be formed on the portion of the supporting film 102' above the sacrificial layer 100-1 by photolithography and etching. The via 102-1' can serve as a release hole for releasing the sacrificial layer 100-1.

[0091] S2.4. Remove the sacrificial layer 100-1 through the through hole 102-1' to form the groove 1021.

[0092] For example, the sacrificial layer 100-1 can be released by dry etching or wet etching, thereby forming a groove 1021 in the area where the sacrificial layer 100-1 was originally located.

[0093] S2.5 Fill the through hole 102-1' with insulating material to form a support layer 102.

[0094] For example, an insulating material, such as silicon nitride, can be deposited in the via 102-1' using CVD (Chemical Vapor Deposition) to seal the via 102-1' and form a support layer 102, thereby forming a pressure cavity 103 between the substrate 101 and the support layer 102.

[0095] Exemplarily, the pressure sensing chip 100 prepared using the preparation method provided in some embodiments of this disclosure is fabricated on a single wafer. Specifically, after forming a pressure-sensitive structure 104 or a portion thereof on the substrate 101 of the wafer, a support layer 102 can be directly formed on the substrate 101. The pressure cavity 103 between the support layer 102 and the substrate 101 can be formed, for example, by preparing a sacrificial layer 100-1, releasing the sacrificial layer 100-1, and filling the vias 102-1' of the released sacrificial layer 100-1. Then, a reinforcing layer 105 is formed on the support layer 102. The pressure sensing chip 100 is fabricated on a single wafer, which reduces the number of wafers required and saves production costs. Simultaneously, the support layer 102 and the reinforcing layer 105 can be directly grown on the substrate 101, saving preparation steps, reducing processing time, and greatly improving production efficiency.

[0096] In some embodiments, the pressure-sensitive structure 104 includes a first capacitor, which includes a first electrode and a second electrode; therefore, before forming the sacrificial layer 100-1 in step S2.1, the method for fabricating the pressure sensing chip 100 further includes:

[0097] A first electrode plate of a pressure-sensitive structure 104 is formed on one side of the pressure-sensitive diaphragm 1011, that is, a first electrode plate of a first capacitor is formed on one side of the pressure-sensitive diaphragm 1011.

[0098] For example, photoresist can be deposited on one side of the substrate 101, and the photoresist can be used as a mask layer to form the pattern required for the first electrode plate of the first capacitor on the photoresist by photolithography; the first electrode plate of the first capacitor can be prepared by ion implantation on the part of the substrate 101 exposed to the photoresist, and after preparation, the photoresist is removed and annealed so that the implanted ions are activated to form the first electrode plate of the first capacitor.

[0099] For example, while forming the first electrode plate of the first capacitor, a lead wire connected to the first electrode plate of the first capacitor can also be formed. That is, the pattern required for the first electrode plate of the first capacitor can be formed on the photoresist by photolithography, and the pattern required for the lead wire can be formed at the same time. The first electrode plate of the first capacitor can be prepared by ion implantation on the part of the substrate 101 exposed to the photoresist, and the lead wire can be prepared at the same time. After preparation, the photoresist is removed and annealing is performed so that the implanted ions are activated to form the first electrode plate of the first capacitor and the lead wire connected thereto.

[0100] For example, the surface of the first electrode of the first capacitor on the side away from the substrate 101 is exposed, and the sacrificial layer 100-1 formed needs to cover the exposed surface of the first electrode of the first capacitor.

[0101] S2.1 After forming the sacrificial layer 100-1, the fabrication method of the pressure sensing chip 100 further includes:

[0102] A second plate of a pressure-sensitive structure 104 is formed on the side of the sacrificial layer 100-1 away from the substrate 101, that is, a second plate of a first capacitor is formed on the side of the sacrificial layer 100-1 away from the substrate 101.

[0103] For example, metal can be deposited and etched on the side of the sacrificial layer 100-1 away from the substrate 101 to form a second electrode plate corresponding to the first electrode plate above the sacrificial layer 100-1.

[0104] In some embodiments, the pressure-sensitive structure 104 includes a pressure-sensitive resistor 104-1; therefore, before forming the sacrificial layer 100-1 in step S2.1, as shown in FIG3, the method for fabricating the pressure sensing chip 100 further includes:

[0105] S1.1 A varistor 104-1 is formed on one side of the pressure-sensitive diaphragm 1011.

[0106] For example, photoresist can be deposited on one side of the substrate 101, and the photoresist can be used as a mask layer to form the required pattern of the varistor 104-1 on the photoresist by photolithography; the varistor 104-1 can be prepared by ion implantation on the part of the substrate 101 exposed to the photoresist. After preparation, the photoresist is removed and annealing is performed so that the implanted ions are activated to form the varistor 104-1.

[0107] For example, while forming the varistor 104-1, the lead 106 connected to the varistor 104-1 can also be formed. That is, the pattern required for the varistor 104-1 can be formed on the photoresist by photolithography, and the pattern required for the lead 106 can be formed at the same time. The varistor 104-1 can be prepared by ion implantation on the photoresist-exposed part of the substrate 101, and the lead 106 can be prepared at the same time. After preparation, the photoresist is removed and annealing is performed so that the implanted ions are activated to form the varistor 104-1 and the lead 106 connected to it.

[0108] For example, the resistance of the formed varistor 104-1 can be from 100Ω / square to 1000Ω / square, and the resistance of the formed lead 106 can be from 20Ω / square to 100Ω / square.

[0109] For example, the surface of the formed varistor 104-1 on the side away from the substrate 101 is exposed, and the formed sacrificial layer 100-1 needs to cover the exposed surface of the varistor 104-1.

[0110] In some embodiments, as shown in FIG3, after forming the reinforcing layer 105 on the side of the support layer 102 away from the substrate 101, the method further includes:

[0111] S4. The substrate 101 is etched to form a pressure-sensitive film 1011 with a thickness smaller than that of the body portion 1012.

[0112] S5. Using photolithography and etching, etch openings 107-1 are made on the reinforcing layer 105 and the support layer 102.

[0113] For example, the diameter of the opening 107-1 can be 10um-1000um; the opening 107-1 penetrates the reinforcing layer 105 and the support layer 102, exposing the lead 106 connected to the varistor 104-1.

[0114] S6. Metal is filled into the opening 107-1 to form a conductive post 107, which is connected to the lead wire 106.

[0115] For example, a seed layer and an electroplated layer can be sequentially deposited on the inner wall of the opening 107-1 using PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition) processes. The seed layer can be made of materials such as titanium, copper, or chromium, and its thickness can be, for example, 20 nm to 50 nm. The electroplated layer can be made of materials such as copper, which fills the opening 107-1 completely.

[0116] S7. A redistribution layer 108 (RDL) is formed on the side of the reinforcing layer 105 away from the substrate 101. The redistribution layer 108 is connected to the conductive pillar 107.

[0117] For example, a seed layer and an electroplated layer can be sequentially deposited on the reinforcing layer 105 using PVD or CVD processes. The seed layer can be made of materials such as titanium, copper, or chromium, and its thickness can be, for example, 20 nm to 50 nm. The electroplated layer can be made of materials such as copper, and its thickness can be, for example, 0.2 μm to 0.5 μm. After electroplating, photolithography is performed to form the required redistribution layer 108.

[0118] S8. An underball metal (UBM) layer 109 is formed on the side of the redistribution layer 108 away from the substrate 101, and the underball metal layer 109 is in contact with the redistribution layer 108.

[0119] For example, the under-bump metal layer 109 can be deposited by PVD or electroplating. The material of the under-bump metal layer 109 can be, for example, indium or an alloy material such as copper-tin. The thickness of the under-bump metal layer 109 can be, for example, 2μm to 15μm.

[0120] S9. A connector 110 is formed on the side of the under-bump metal layer 109 away from the substrate 101, and the connector 110 contacts the under-bump metal layer 109.

[0121] For example, the connector 110 can be a solder ball. Solder paste can be applied to the top of the under-bump metal layer 109 by screen printing, and then the solder ball can be prepared by thermal reflow.

[0122] For example, the above preparation method can also be applied to the preparation of chips with vacuum cavity or sealed cavity structures.

[0123] In some embodiments, as shown in Figures 4 and 5, a pressure sensing chip 100 is provided. The pressure sensing chip 100 includes a substrate 101, a support layer 102, a pressure-sensitive structure 104, and a reinforcing layer 105. The substrate 101 includes a pressure-sensitive membrane portion 1011. The support layer 102 is disposed on one side of the substrate 101, and a groove 1021 is formed on the surface of the support layer 102 near the substrate 101, forming a pressure cavity 103 between the groove 1021 and the pressure-sensitive membrane portion 1011. At least a portion of the pressure-sensitive structure 104 is embedded in the surface of the pressure-sensitive membrane portion 101 near the support layer 102, and a portion of the surface of the pressure-sensitive structure 104 is exposed in the pressure cavity 103. The reinforcing layer 105 is disposed on the side of the support layer 102 away from the substrate 101.

[0124] In some embodiments, as shown in Figures 4 and 5, the substrate 101 can be used to support other structures of the pressure sensing chip 100. The substrate 101 can be, for example, a silicon substrate. The substrate 101 includes a pressure-sensitive diaphragm portion 1011 and a body portion 1012, the body portion 1012 being disposed around the pressure-sensitive diaphragm portion 1011, for example. The pressure-sensitive diaphragm portion 1011 is used to convert pressure signals into deformation signals.

[0125] In some embodiments, as shown in Figures 4 and 5, a support layer 102 is disposed on one side of a substrate 101. The material of the support layer 102 may be, for example, silicon nitride. The support layer 102 may be formed directly on one side of the substrate 101, thereby reducing the number of wafers required for the pressure sensing chip 100.

[0126] In some embodiments, as shown in Figures 4 and 5, a groove 1021 is formed on the surface of the support layer 102 near the substrate 101. The groove 1021 includes a sidewall 1021-2 and a bottom wall 1021-1, with the sidewall 1021-2 surrounding the bottom wall 1021-1. A pressure cavity 103 is formed between the groove 1021 and the pressure-sensitive diaphragm 1011, that is, the sidewall 1021-2, the bottom wall 1021-1 of the groove 1021, and the surface of the pressure-sensitive diaphragm 1011 near the support layer 102 enclose a closed pressure cavity 103. The pressure chamber 103 can be prepared by first forming a sacrificial layer 100-1 on one side of the substrate 101, forming a support layer 102 on the sacrificial layer 100-1, and setting a through hole 102-1' in the part of the support layer 102 above the sacrificial layer 100-1. The sacrificial layer 100-1 is released through the through hole 102-1', and then the through hole 102-1' is filled to form the pressure chamber 103.

[0127] The orthographic projection of the groove 1021 onto the substrate 101 can cover the pressure-sensitive membrane 1011, partially overlap with the pressure-sensitive membrane 1011, or be located within the area defined by the pressure-sensitive membrane 1011. This disclosure does not limit these possibilities.

[0128] In some embodiments, the pressure value inside the pressure chamber 103 is a reference pressure for the pressure sensor chip 100 to measure the pressure. When the external pressure value is equal to the pressure value inside the pressure chamber 103, the output of the pressure sensor chip 100 is zero. When the external pressure is greater than the pressure inside the pressure chamber 103, the output of the pressure sensor chip 100 is the external atmospheric pressure minus the pressure inside the pressure chamber 103.

[0129] In some embodiments, as shown in Figures 4 and 5, at least a portion of the pressure-sensitive structure 104 is embedded on the side surface of the pressure-sensitive diaphragm 1011 near the support layer 102, and a portion of the surface of the pressure-sensitive structure 104 is exposed in the pressure chamber 103. The pressure-sensitive structure 104 is used to convert the deformation signal of the pressure-sensitive diaphragm 1011 into an electrical signal.

[0130] In some embodiments, at least a portion of the pressure-sensitive structure 104 is embedded in the surface of the pressure-sensitive diaphragm 1011 near the support layer 102. For example, as shown in FIG4, when the pressure-sensitive structure 104 is a resistor, the resistor is embedded in the surface of the pressure-sensitive diaphragm 101 near the support layer 102, and the surface of the resistor away from the substrate 101 is exposed in the pressure chamber 103. As another example, as shown in FIG5, when the pressure-sensitive structure 104 is a capacitor, only the lower electrode of the capacitor is embedded in the surface of the pressure-sensitive diaphragm 101 near the support layer 102, and the surface of the lower electrode of the capacitor away from the substrate 101 is exposed in the pressure chamber 103, while the upper electrode of the capacitor may be disposed on the bottom wall 1021-1 of the groove 1021.

[0131] For example, a portion of the surface of the varistor 104 refers to a portion of the outer surface of the varistor 104; when the varistor 104 is a resistor, a portion of the surface of the varistor 104 refers to the surface of the varistor 104 away from the substrate 101; when the varistor 104 is a capacitor, a portion of the surface of the varistor 104 refers to the surface of the lower plate of the capacitor away from the substrate 101, and the surface of the upper plate of the capacitor other than the surface that contacts the bottom wall 1021-1 of the groove 1021.

[0132] In some embodiments, as shown in Figures 4 and 5, due to the limitations of the material of the support layer 102 formed directly on one side of the substrate 101, the support layer 102 has low hardness and the portion of the support layer 102 above the pressure chamber 103 is relatively thin, resulting in insufficient support strength. When external pressure is applied, the support layer 102 is easily crushed, thereby damaging the pressure sensing chip 100. Therefore, a reinforcing layer 105 needs to be provided on the side of the support layer 102 away from the substrate 101. The reinforcing layer 105 can serve as a reinforcing structure for the pressure chamber 103, preventing the support layer 102 above the pressure chamber 103 from being crushed and damaging the structure of the pressure chamber 103. The material of the reinforcing layer 105 can be, for example, polycrystalline silicon.

[0133] This disclosure does not limit the materials of the substrate 101, the support layer 102, and the reinforcing layer 105, as long as they can achieve the functions of each membrane layer.

[0134] Exemplary examples show that the pressure sensing chip 100 provided in some embodiments of this disclosure is fabricated on a single wafer. That is, after forming a pressure-sensitive structure 104 or a portion thereof on the substrate 101 of the wafer, a support layer 102 can be directly formed on the substrate 101. The pressure cavity 103 between the support layer 102 and the substrate 101 can be formed, for example, by fabricating a sacrificial layer 100-1, releasing the sacrificial layer 100-1, and filling the vias 102-1' of the released sacrificial layer 100-1. Then, a reinforcing layer 105 is formed on the support layer 102. The pressure sensing chip 100 being fabricated on a single wafer reduces the number of wafers required, saving production costs. Simultaneously, the support layer 102 and the reinforcing layer 105 can be directly grown on the substrate 101, saving fabrication steps, reducing processing time, and greatly improving production efficiency.

[0135] In some embodiments, as shown in Figures 6, 7, 8, and 9, the pressure sensing chip 100 further includes a reinforcing structure 111, which is located within the pressure chamber 103 and connected to the bottom wall 1021-1 of the groove 1021; the orthographic projection of the reinforcing structure 111 on the substrate 101 does not overlap with the orthographic projection of the pressure-sensitive structure 104 on the substrate 101.

[0136] In some embodiments, the reinforcing structure 111 can be used to enhance the performance of the pressure sensing chip 100. For example, the reinforcing structure 111 can be used to increase the sensitivity of the pressure sensing chip 100, or the reinforcing structure 111 can be used to increase the overload resistance of the pressure sensing chip 100. This disclosure does not limit the scope of the invention.

[0137] In some embodiments, as shown in Figures 6, 7, 8, and 9, the reinforcing structure 111 is disposed in the pressure chamber 103, and one side surface of the reinforcing structure 111 is connected to the bottom wall 1021-1 of the groove 1021. Therefore, the reinforcing structure 111 can be integrally prepared with the support layer 102, that is, the reinforcing structure 111 and the support layer 102 are integrally formed.

[0138] In some embodiments, as shown in Figures 6, 7, 8, and 9, to ensure the normal operation of the pressure sensing chip 100 and prevent the reinforcing structure 111 from damaging the pressure-sensitive structure 104, the orthographic projection of the reinforcing structure 111 on the substrate 101 must not overlap with the orthographic projection of the pressure-sensitive structure 104 on the substrate 101; that is, the reinforcing structure 111 and the pressure-sensitive structure 104 each occupy independent spaces. A top view of the reinforcing structure 111 and the pressure-sensitive structure 104 can be shown in Figure 10.

[0139] For example, the distribution of the reinforcing structure 111 and the pressure-sensitive structure 104 is not limited to the case shown in FIG10. There can be other distribution methods, as long as the orthographic projection of the reinforcing structure 111 on the substrate 101 and the orthographic projection of the pressure-sensitive structure 104 on the substrate 101 do not overlap.

[0140] In some embodiments, as shown in Figures 6 and 7, the surface of the reinforcing structure 111 near the pressure-sensitive diaphragm 1011 is connected to the pressure-sensitive diaphragm 1011, which can form a corner at the connection point between the reinforcing structure 111 and the pressure-sensitive diaphragm 1011. The corner can concentrate stress at the corner location. That is, when the pressure-sensitive diaphragm 1011 receives external pressure, it deforms, and the stress generated by the deformation will be concentrated at the corner location, thus amplifying the deformation of the pressure-sensitive diaphragm 1011. This can greatly improve the sensitivity of the pressure sensing chip 100 and obtain more accurate measurement results.

[0141] In some embodiments, as shown in Figures 6 and 7, the surface of the reinforcing structure 111 near the pressure-sensitive diaphragm 1011 forms a right angle at the point where it connects with the pressure-sensitive diaphragm 1011. When the angle formed at the point where the reinforcing structure 111 connects with the pressure-sensitive diaphragm 1011 is a right angle, the right angle structure allows the stress generated by the deformation of the pressure-sensitive diaphragm 1011 to be concentrated over a larger area at the right angle location, further improving the sensitivity of the pressure sensing chip 100 and obtaining more accurate measurement results.

[0142] In some embodiments, when the pressure sensing chip 100 is subjected to external pressure, the pressure-sensing diaphragm 1011 deforms in the direction of the pressure chamber 103 (the external pressure acts on the side where the substrate 101 is located). Generally, when the external pressure is at full scale, the deformation of the pressure-sensing diaphragm 1011 is, for example, less than 5 μm. However, in actual use, the pressure sensing chip 100 may be subjected to pressures far exceeding its full scale, which will cause significant deformation or damage to the pressure-sensing diaphragm 1011, resulting in the failure of the pressure sensing chip 100.

[0143] Therefore, it is necessary to improve the overload resistance of the pressure sensing chip 100 and increase its service life.

[0144] In some embodiments, as shown in Figures 8 and 9, the reinforcing structure 111 is spaced apart from the pressure-sensing diaphragm 1011 on the side surface near the pressure-sensing diaphragm 1011, meaning there is a certain distance between the reinforcing structure 111 and the pressure-sensing diaphragm 1011. When the pressure sensing chip 100 is subjected to a pressure much greater than its full-scale range, and the pressure-sensing diaphragm 1011 undergoes significant deformation, the reinforcing structure 111 blocks the pressure-sensing diaphragm 1011, preventing it from undergoing even greater deformation and breaking. This greatly improves the overload resistance and reliability of the pressure sensing chip 100.

[0145] In some embodiments, as shown in Figures 8 and 9, along the thickness direction of the substrate 101, the distance between the reinforcing structure 111 and the substrate 101 is 1 to 2 times the distance by which the pressure-sensing diaphragm 1011 deforms when the pressure sensing chip 100 is subjected to full-scale pressure. This arrangement can both enable the reinforcing structure 111 to resist overload and prevent the pressure-sensing diaphragm 1011 from undergoing greater deformation and breaking, and prevent the reinforcing structure 111 from affecting the normal deformation of the pressure-sensing diaphragm 1011, thereby affecting the performance of the pressure sensing chip 100.

[0146] In some embodiments, as shown in Figures 6, 7, 8, and 9, the centerline of the pressure-sensitive membrane portion 1011 penetrates the reinforcing structure 111 along the thickness direction of the substrate 101.

[0147] For example, the center line of the pressure-sensitive diaphragm 1011 is a straight line along the thickness direction of the substrate 101 at the location of the center point on the pressure-sensitive diaphragm 1011.

[0148] For example, the center point is the point in the graph whose sum of distances to all other points is the smallest.

[0149] For example, when the pressure-sensitive diaphragm 1011 is square, the center point of the pressure-sensitive diaphragm 1011 is the intersection of the two diagonals of the square. As another example, when the pressure-sensitive diaphragm 1011 is circular, the center point of the pressure-sensitive diaphragm 1011 is the dot of the circle.

[0150] For example, along the thickness direction of the substrate 101, the center line of the pressure-sensitive diaphragm 1011 passes through the reinforcing structure 111. That is, the orthographic projection of the reinforcing structure 111 on the substrate 101 covers the center point of the pressure-sensitive diaphragm 1011. The reinforcing structure 111 is located in the middle of the pressure-sensitive diaphragm 1011. Since the center point of the pressure-sensitive diaphragm 1011 undergoes the greatest deformation under pressure, the reinforcing structure 111 can concentrate more stress, thereby improving the sensitivity of the pressure sensing chip 100. Alternatively, the reinforcing structure 111 can effectively block the pressure-sensitive diaphragm 1011 from undergoing large deformation, preventing excessive deformation of the pressure-sensitive diaphragm 1011 from causing damage. This can better achieve the reinforcing effect of the pressure sensing chip 100 and further improve the reliability of the pressure sensing chip 100.

[0151] In some embodiments, as shown in FIG5, the pressure-sensitive structure 104 includes a first capacitor 104-2, the first capacitor 104-2 including a first electrode plate 104-21 and a second electrode plate 104-22 disposed opposite to each other; the first electrode plate 104-21 is embedded on the side surface of the pressure-sensitive membrane portion 1011 near the support layer 102, and the side surface of the first electrode plate 104-21 away from the pressure-sensitive membrane portion 1011 is exposed in the pressure chamber 103; the second electrode plate 104-22 is disposed on the bottom wall 1021-1 of the groove 1021.

[0152] For example, as shown in FIG5, the pressure-sensitive structure 104 can be a first capacitor 104-2. The first electrode 104-21 of the first capacitor 104-2 is embedded on the side surface of the pressure-sensitive membrane 1011 near the support layer 102, and the side surface of the first electrode 104-21 away from the pressure-sensitive membrane 1011 is exposed in the pressure chamber 103. The first electrode 104-21 can be the lower electrode of the first capacitor 104-2. The first electrode 104-21 is a movable electrode, and the first electrode 104-21 moves with the deformation of the pressure-sensitive membrane 1011.

[0153] For example, as shown in FIG5, the second electrode plate 104-22 of the first capacitor 104-2 is disposed on the bottom wall 1021-1 of the groove 1021. The second electrode plate 104-22 and the first electrode plate 104-21 are disposed opposite to each other. The second electrode plate 104-22 can be, for example, the upper electrode plate of the first capacitor 104-2. The second electrode plate 104-22 is a fixed electrode plate, which is fixed on the bottom wall 1021-1 of the groove 1021 and does not move.

[0154] For example, when the pressure sensing chip 100 is subjected to external pressure, the pressure-sensing diaphragm 1011 deforms in the direction of the pressure chamber 103. The first electrode 104-21 moves in the direction of the pressure chamber 103 along with the pressure-sensing diaphragm 1011, while the second electrode 104-22 remains fixed. This causes the capacitance value of the first capacitor 104-2 to change, and the pressure value of the external pressure can be obtained from the capacitance value of the first capacitor 104-2.

[0155] In some embodiments, as shown in FIG11, the pressure-sensitive structure 104 further includes a second capacitor 104-3, the second capacitor 104-3 including a third electrode plate 104-31 and a fourth electrode plate 104-32 disposed opposite to each other; the third electrode plate 104-31 is embedded on the side surface of the pressure-sensitive membrane portion 1011 near the support layer 102, and the side surface of the third electrode plate 104-31 away from the pressure-sensitive membrane portion 1011 is exposed in the pressure chamber 103; the fourth electrode plate 104-32 is disposed on the bottom wall 1021-1 of the groove 1021; wherein, the orthographic projection of the first capacitor 104-2 on the substrate 101 and the orthographic projection of the second capacitor 104-3 on the substrate 101 do not overlap; along the thickness direction of the substrate 101, the center line of the pressure-sensitive membrane portion 1011 passes through the first capacitor 104-2.

[0156] In some embodiments, as shown in FIG11, the orthographic projection of the first capacitor 104-2 on the substrate 101 and the orthographic projection of the second capacitor 104-3 on the substrate 101 do not overlap, that is, the first capacitor 104-2 and the second capacitor 104-3 are respectively independently arranged.

[0157] For example, as shown in FIG11, the third electrode 104-31 of the second capacitor 104-3, like the first electrode 104-21 of the first capacitor 104-2, is embedded on the surface of the pressure-sensitive diaphragm 1011 near the support layer 102, and the surface of the third electrode 104-31 away from the pressure-sensitive diaphragm 1011 is exposed in the pressure chamber 103. The third electrode 104-31 can be, for example, the lower electrode of the second capacitor 104-3; the third electrode 104-31 of the second capacitor 104-3 is also a movable electrode, and the third electrode 104-31 moves with the deformation of the pressure-sensitive diaphragm 1011.

[0158] For example, as shown in FIG11, the fourth electrode plate 104-32 of the second capacitor 104-3 is the same as the second electrode plate 104-22 of the first capacitor 104-2, and is disposed on the bottom wall 1021-1 of the groove 1021. The fourth electrode plate 104-32 is disposed opposite to the third electrode plate 104-31. The fourth electrode plate 104-32 can be, for example, the upper electrode plate of the second capacitor 104-3. The fourth electrode plate 104-32 is a fixed electrode plate, which is fixed on the bottom wall 1021-1 of the groove 1021 and does not move.

[0159] For example, when the pressure sensing chip 100 is subjected to external pressure, the pressure-sensing diaphragm 1011 deforms in the direction of the pressure chamber 103. The third electrode 104-31 moves in the direction of the pressure chamber 103 along with the pressure-sensing diaphragm 1011, while the fourth electrode 104-32 remains fixed. This causes the capacitance value of the second capacitor 104-3 to change, and the pressure value of the external pressure can be obtained from the capacitance value of the second capacitor 104-3.

[0160] For example, as shown in FIG11, the center line of the pressure-sensitive diaphragm 1011 passes through the first capacitor 104-2 along the thickness direction of the substrate 101. That is, the orthogonal projection of the first capacitor 104-2 on the substrate 101 covers the center point of the pressure-sensitive diaphragm 1011. Since the center point of the pressure-sensitive diaphragm 1011 undergoes the greatest deformation after being subjected to pressure, the capacitance value of the first capacitor 104-2 changes more significantly than that of the second capacitor 104-3. Furthermore, the time required for the capacitance value of the first capacitor 104-2 to reach its limit is shorter than the time required for the capacitance value of the second capacitor 104-3 to reach its limit. Therefore, the first capacitor 104-2 can be used as a low-range capacitor structure, and the pressure can be measured by the capacitance value of the first capacitor 104-2 when the pressure is less than a certain value; the second capacitor 104-3 can be used as a high-range capacitor structure, and the pressure can be measured by the capacitance value of the second capacitor 104-3 when the pressure is greater than a certain value.

[0161] For example, during the use of the pressure sensing chip 100, when the pressure sensing chip 100 is subjected to external pressure, the pressure-sensing diaphragm 1011 deforms in the direction of the pressure chamber 103. The first electrode 104-21 of the first capacitor 104-2 and the third electrode 104-31 of the second capacitor 104-3 both move in the direction of the pressure chamber 103 along with the pressure-sensing diaphragm 1011. Since the first electrode 104-21 of the first capacitor 104-2 is located in the middle of the pressure-sensing diaphragm 1011, the deformation of the first electrode 104-21 with the pressure-sensing diaphragm 1011 is greater when subjected to the same pressure. In other words, the first electrode 104-21 of the first capacitor 104-2 is more sensitive to pressure. Therefore, before the first electrode 104-21 and the second electrode 104-22 of the first capacitor 104-2 are bonded together, the pressure can be measured using the capacitance value of the first capacitor 104-2. When external pressure causes the first plate 104-21 and the second plate 104-22 of the first capacitor 104-2 to be completely in contact, the first plate 104-21 and the second plate 104-22 of the first capacitor 104-2 are conductive, and there is no capacitance between the first plate 104-21 and the second plate 104-22 of the first capacitor 104-2. At this time, the capacitance value of the second capacitor 104-3 can be used to measure the pressure.

[0162] For example, this setting increases the sensitivity of the pressure sensing chip 100, allowing smaller pressures to be accurately measured by the highly sensitive first capacitor 104-2; at the same time, this setting also increases the measurement range of the pressure sensing chip 100, enabling the pressure sensing chip 100 to measure larger pressures without damaging the pressure sensing chip 100, thus ensuring the sensitivity and reliability of the pressure sensing chip 100.

[0163] In some embodiments, as shown in FIG12, the orthographic projection of the second capacitor 104-3 on the substrate 101 is disposed around the outer edge of the orthographic projection of the first capacitor 104-2 on the substrate 101.

[0164] For example, as shown in FIG12, the top view of the first electrode plate 104-21 of the first capacitor 104-2 and the third electrode plate 104-31 of the second capacitor 104-3 on the substrate 101 is shown in FIG12(a), and the top view of the second electrode plate 104-22 of the first capacitor 104-2 and the fourth electrode plate 104-32 of the second capacitor 104-3 on the support layer 102 is shown in FIG12(b). The patterns of the first electrode plate 104-21 and the second electrode plate 104-22 of the first capacitor 104-2 can be the same and arranged opposite to each other, and the patterns of the third electrode plate 104-31 and the fourth electrode plate 104-32 of the second capacitor 104-3 can be the same and arranged opposite to each other.

[0165] In some embodiments, as shown in FIG13, the substrate 101 further includes a body portion 1012, which is disposed around the pressure-sensitive membrane portion 1011; a pressure channel 112 is disposed within the pressure sensing chip 100, and the pressure channel 112 includes a first portion 1121 and a second portion 1122 that are connected; the first portion 1121 penetrates through the body portion 1012 and a portion of the support layer 102, and the second portion 1122 is disposed within the support layer 102 and is located between the pressure cavity 103 and the reinforcing layer 105; the orthographic projection of the second portion 1122 on the substrate 101 covers the orthographic projection of the pressure cavity 103 on the substrate 101.

[0166] In some embodiments, as shown in FIG13, a pressure channel 112 is embedded in the body portion 1012 and the support layer 102. The pressure channel 112 includes a first portion 1121 and a second portion 1122 that are connected. The first portion 1121 is disposed in a direction perpendicular to the surface of the body portion 1012, and the first portion 1121 penetrates the body portion 1012 and also penetrates a portion of the support layer 102. The second portion 1122 is disposed in a direction parallel to the surface of the body portion 1012, the second portion 1122 is located in the support layer 102, and the second portion 1122 is located between the pressure chamber 103 and the reinforcing layer 105, and communicates with the first portion 1121.

[0167] In some embodiments, as shown in FIG13, the orthographic projection of the second portion 1122 on the substrate 101 covers the orthographic projection of the pressure cavity 103 on the substrate 101, that is, the second portion 1122 is located above the pressure cavity 103, and the pressure cavity 103 is located in the area covered by the second portion 1122.

[0168] In some embodiments, as shown in FIG13, a first capacitor 104-2 is disposed in the pressure chamber 103. The first electrode 104-21 of the first capacitor 104-2 is embedded in the side surface of the pressure-sensing diaphragm 1011 near the support layer 102. The first electrode 104-21 of the first capacitor 104-2 is a movable electrode. When the pressure sensing chip 100 is subjected to external pressure, the first electrode 104-21 deforms in the direction of the pressure chamber 103 along with the pressure-sensing diaphragm 1011.

[0169] In some embodiments, as shown in FIG13, the second electrode plate 104-22 of the first capacitor 104-2 is disposed on the bottom wall 1021-1 of the groove 1021. The second electrode plate 104-22 is also a movable electrode plate. When the pressure sensing chip 100 is subjected to external pressure, the external pressure is transmitted to the second part 1122 through the first part 1121 of the pressure channel 112, and then applied to the support layer 102 between the second part 1122 and the pressure chamber 103 through the second part 1122. Under the action of external pressure, the support layer 102 between the second part 1122 and the pressure chamber 103 deforms in the direction of the pressure chamber 103. The second electrode plate 104-22 also deforms in the direction of the pressure chamber 103 along with the support layer 102 between the second part 1122 and the pressure chamber 103, thereby causing the second electrode plate 104-22 to move.

[0170] For example, when the pressure sensing chip 100 is subjected to external pressure, the first electrode 104-21 and the second electrode 104-22 simultaneously deform in the direction of the pressure chamber 103, causing a change in the capacitance value of the first capacitor 104-2, thereby allowing the determination of the external pressure value. This configuration allows both electrodes of the first capacitor 104-2 to deform, even with a small applied external pressure, resulting in a change in the capacitance value of the first capacitor 104-2, which greatly increases the sensitivity of the first capacitor 104-2.

[0171] In some embodiments, as shown in FIG4, the pressure-sensitive structure 104 includes a plurality of pressure-sensitive resistors 104-1, which are embedded on the side surface of the pressure-sensitive diaphragm portion 1011 near the support layer 102.

[0172] For example, the pressure-sensitive structure 104 can be a pressure-sensitive resistor 104-1. When the pressure sensing chip 100 is subjected to external pressure, the external pressure causes the pressure-sensitive diaphragm 1011 to deform. The pressure-sensitive resistor 104-1 embedded on the side surface of the pressure-sensitive diaphragm 1011 near the support layer 102 converts the deformation signal of the pressure-sensitive diaphragm 1011 into a resistance signal. That is, the pressure-sensitive resistor 104-1 outputs different resistance values ​​according to the magnitude of the deformation generated by the pressure-sensitive diaphragm 1011, thereby obtaining the pressure value of the external pressure.

[0173] In some embodiments, as shown in FIG14, a reference pressure cavity 113 is further provided in the support layer 102, the reference pressure cavity 113 is located on the side of the pressure cavity 103 away from the substrate 101; the pressure sensing chip 100 also includes a reference pressure-sensitive structure 114, a portion of the surface of the reference pressure-sensitive structure 114 is exposed in the reference pressure cavity 113, and the reference pressure-sensitive structure 114 is configured to have the same structural type as the pressure-sensitive structure 104.

[0174] In some embodiments, as shown in FIG14, a reference pressure cavity 113 is also provided in the support layer 102. The shape and volume of the reference pressure cavity 113 may be the same as the shape and volume of the pressure cavity 103. Of course, due to deviations in the manufacturing process, the shape and volume of the reference pressure cavity 113 may deviate from the shape and volume of the pressure cavity 103. This disclosure does not limit this.

[0175] In some embodiments, as shown in FIG14, the reference pressure chamber 113 is located on the side of the pressure chamber 103 away from the substrate 101, that is, the reference pressure chamber 113 is located above the pressure chamber 103. The reference pressure chamber 113 is used to set the reference pressure-sensitive structure 114. Part of the surface of the reference pressure-sensitive structure 114 is exposed in the reference pressure chamber 113. The reference pressure-sensitive structure 114 serves as a correction structure for the pressure-sensitive structure 104 and is used to correct error terms such as parasitic capacitance and temperature error of the pressure-sensitive structure 104.

[0176] In some embodiments, as shown in FIG14, the reference pressure-sensitive structure 114 is a fixed structure that does not change with the change of external pressure. During the use of the pressure sensing chip 100, the final output value of the pressure sensing chip 100, for example, is the capacitance value of the pressure-sensitive structure 104 minus the capacitance value of the reference pressure-sensitive structure 114. This eliminates parasitic capacitance, temperature error, and other error terms in the pressure-sensitive structure 104 of the pressure sensing chip 100, thereby improving the accuracy of the pressure sensing chip 100.

[0177] In some embodiments, as shown in FIG14, to ensure data accuracy, the reference piezoresistive structure 114 needs to have the same structural type as the piezoresistive structure 104. That is, when the piezoresistive structure 104 is a capacitor, the reference piezoresistive structure 114 is also a capacitor; when the piezoresistive structure 104 is a resistor, the reference piezoresistive structure 114 is also a resistor. This ensures that the parasitic capacitance and other parameters of the reference piezoresistive structure 114 and the piezoresistive structure 104 are the same. The reference pressure chamber 113 is located on the side of the pressure chamber 103 away from the substrate 101, so that the temperature of the environment in which the reference piezoresistive structure 114 and the piezoresistive structure 104 are located is the same. This can eliminate error terms such as parasitic capacitance and temperature error of the pressure sensing chip 100 and improve the accuracy of the pressure sensing chip 100.

[0178] In some embodiments, as shown in FIG14, the pressure-sensitive structure 104 includes a first capacitor 104-2, and the reference pressure-sensitive structure 114 includes a reference capacitor 114-1; the reference capacitor 114-1 includes a first reference electrode 114-11 and a second reference electrode 114-12 disposed opposite to each other; the first reference electrode 114-11 is disposed on the side surface of the reference pressure cavity 113 away from the substrate 101, and the second reference electrode 114-12 is embedded in the support layer 102 on the side of the reference pressure cavity 113 close to the substrate 101, and the surface of the second reference electrode 114-12 away from the substrate 101 is exposed in the reference pressure cavity 113.

[0179] For example, as shown in FIG14, the structure of the first capacitor 104-2 refers to the structure of the first capacitor 104-2 in some of the embodiments above, and will not be described again here.

[0180] In some embodiments, as shown in FIG14, the reference capacitor 114-1 includes a first reference plate 114-11 and a second reference plate 114-12 disposed opposite to each other; the first reference plate 114-11 is disposed on the side surface of the reference pressure chamber 113 away from the substrate 101, and the first reference plate 114-11 is a fixed plate, and the first reference plate 114-11 does not change with the change of external pressure.

[0181] In some embodiments, as shown in FIG14, the second reference electrode 114-12 is embedded in the support layer 102 of the reference pressure chamber 113 near the substrate 101, and the surface of the second reference electrode 114-12 away from the substrate 101 is exposed in the reference pressure chamber 113. The second reference electrode 114-12 is also a fixed electrode, and the second reference electrode 114-12 does not change with the change of external pressure.

[0182] For example, the structure of the reference capacitor 114-1 is the same as that of the first capacitor 104-2. For instance, the size of the first reference plate 114-11 and the second reference plate 114-12 of the reference capacitor 114-1 is the same as the size of the first plate 104-21 and the second plate 104-22 of the first capacitor 104-2, so that the reference capacitor 114-1 and the first capacitor 104-2 have approximately the same parasitic capacitance, etc.

[0183] In some embodiments, as shown in FIG15, the pressure-sensitive structure 104 includes a pressure-sensitive resistor 104-1, and the reference pressure-sensitive structure 114 includes a reference resistor 114-2. The reference resistor 114-2 is embedded in the support layer 102 of the reference pressure cavity 113 near the substrate 101, and the surface of the reference resistor 114-2 away from the substrate 101 is exposed in the reference pressure cavity 113.

[0184] In some embodiments, as shown in FIG15, the structure of the varistor 104-1 refers to the structure of the varistor 104-1 in some of the embodiments above, and will not be described again here.

[0185] In some embodiments, as shown in FIG15, the reference resistor 114-2 is embedded in the support layer 102 on the side of the reference pressure chamber 113 near the substrate 101, and the surface of the reference resistor 114-2 away from the substrate 101 is exposed in the reference pressure chamber 113. The reference resistor 114-2 is a fixed resistor and does not change with the change of external pressure.

[0186] In some embodiments, the structure of the reference resistor 114-2 is the same as that of the varistor 104-1. For example, the size of the reference resistor 114-2 is the same as that of the varistor 104-1, such that the reference resistor 114-2 and the varistor 104-1 have approximately the same parasitic capacitance.

[0187] In some embodiments, the substrate 101 further includes a body portion 1012, which is disposed around the pressure-sensitive membrane portion 1011; as shown in FIG15, the thickness of the body portion 1012 is greater than the thickness of the pressure-sensitive membrane portion 1011; or, as shown in FIG16, the thickness of the body portion 1012 is equal to the thickness of the pressure-sensitive membrane portion 1011.

[0188] In some embodiments, as shown in FIG15, when the thickness of the body portion 1012 is greater than the thickness of the pressure-sensitive film portion 1011, it is necessary to etch the substrate 101 to form a pressure-sensitive film portion 1011 with a thickness less than that of the body portion 1012. For example, silicon nitride can be grown at the bottom of the substrate 101 as a mask layer. After the silicon nitride deposition is completed, the required shape of the pressure-sensitive film portion 1011 is photolithographically etched on the silicon nitride. Then, the portion of the substrate 101 exposed to silicon nitride is etched. After etching is completed, the silicon nitride mask layer is removed, thereby forming a pressure-sensitive film portion 1011 with a thickness less than that of the body portion 1012. In this fabrication method, the substrate 101 needs to be dry-etched or wet-etched. The etching rate of this method is low, usually less than 1 μm / min, which leads to low production efficiency and high production cost.

[0189] In some embodiments, as shown in FIG16, the substrate 101 can be ground and polished as a whole, and the maximum thinning rate of the substrate 101 can reach more than 10 μm / min, which can greatly improve production efficiency and reduce production costs. At this time, the final thickness of the body portion 1012 is equal to the thickness of the pressure-sensitive membrane portion 1011.

[0190] The thickness of the pressure-sensitive diaphragm 1011 can be set according to the actual situation, and the thickness of the body 1012 can be set according to the actual situation. This disclosure does not impose any restrictions on this.

[0191] In some embodiments, as shown in Figures 14 and 15, the pressure sensing chip 100 further includes a lead 106, a conductive post 107, a redistribution layer 108, and a connector 110; the lead 106 is embedded in the support layer 102 and connected to the pressure-sensitive structure 104; the conductive post 107 penetrates at least a portion of the reinforcing layer 105 and the support layer 102 and is connected to the lead 106; the redistribution layer 108 is disposed on the side of the reinforcing layer 105 away from the substrate 101 and is connected to the conductive post 107; the connector 110 is connected to the side of the redistribution layer 108 away from the substrate 101.

[0192] In some embodiments, as shown in Figures 14 and 15, the pressure-sensitive structure 104 needs to be connected to the lead wire 106, and the signal of the pressure-sensitive structure 104 is output through the lead wire 106.

[0193] In some embodiments, as shown in FIG14, when the pressure-sensitive structure 104 is a first capacitor 104-2, the first plate 104-21 of the first capacitor 104-2 is connected to a lead 106, for example, the first plate 104-21 is connected to the first lead 106-1, and the signal of the first plate 104-21 is output through the first lead 106-1; the second plate 104-22 of the first capacitor 104-2 is connected to another lead 106, for example, the second plate 104-22 is connected to the second lead 106-2, and the signal of the second plate 104-22 is output through the second lead 106-2.

[0194] In some embodiments, as shown in FIG14, when the pressure sensing chip 100 further includes a reference capacitor 114-1, the first reference plate 114-11 of the reference capacitor 114-1 is connected to another lead 106, for example, the first reference plate 114-11 is connected to the third lead 106-3, and the signal of the first reference plate 114-11 is output through the third lead 106-3; the second reference plate 114-12 of the reference capacitor 114-1 is connected to another lead 106, for example, the second reference plate 114-12 is connected to the fourth lead 106-4, and the signal of the second reference plate 114-12 is output through the fourth lead 106-4.

[0195] In some embodiments, as shown in FIG15, when the varistor 104 is a varistor 104-1, the varistor 104-1 is connected to the lead 106, for example, the varistor 104-1 is connected to the resistor lead 106-5, and the signal of the varistor 104-1 is output through the resistor lead 106-5.

[0196] In some embodiments, as shown in FIG15, when the pressure sensing chip 100 further includes a reference resistor 114-2, the reference resistor 114-2 is connected to another lead 106, for example, the reference resistor 114-2 is connected to a reference resistor lead 106-6, and the signal of the reference resistor 114-2 is output through the reference resistor lead 106-6.

[0197] In some embodiments, at least a portion of the varistor structure 104 can be fabricated simultaneously with the lead 106. For example, as shown in FIG14, when the varistor structure 104 is a first capacitor 104-2, the lead 106 (first lead 106-1) can be fabricated simultaneously with the fabrication of the first electrode 104-21 of the first capacitor 104-2, and the lead 106 is connected to the first electrode 104-21, so that a portion of the varistor structure 104 can be fabricated simultaneously with the lead 106. As another example, as shown in FIG15, when the varistor structure 104 is a varistor 104-1, the lead 106 (resistor lead 106-5) can be fabricated simultaneously with the fabrication of the varistor 104-1, and the lead 106 is connected to the varistor 104-1, so that the varistor structure 104 can be fabricated simultaneously with the lead 106.

[0198] In some embodiments, as shown in Figures 14 and 15, the pressure sensing chip 100 may also be provided with conductive pillars 107. The conductive pillars 107 can serve as electrical connection structures for the pressure sensing chip 100. The conductive pillars 107 penetrate at least a portion of the reinforcing layer 105 and the support layer 102 and are in contact with the leads 106, so that the signals on the leads 106 can be transmitted through the conductive pillars 107. One conductive pillar 107 can be connected to one lead 106.

[0199] In some embodiments, as shown in Figures 14 and 15, the pressure sensing chip 100 may also be provided with a redistribution layer 108. The redistribution layer 108 can serve as an electrical connection structure for the pressure sensing chip 100. The redistribution layer 108 is disposed on the side of the reinforcing layer 105 away from the substrate 101 and is in contact with the conductive post 107. This allows the signal on the conductive post 107 to be transmitted through the redistribution layer 108. One redistribution layer 108 can be connected to one conductive post 107.

[0200] In some embodiments, as shown in Figures 14 and 15, the pressure sensing chip 100 may also be provided with a bump under-metal layer 109. The bump under-metal layer 109 can serve as an electrical connection structure of the pressure sensing chip 100. The bump under-metal layer 109 is disposed on the side of the redistribution layer 108 away from the substrate 101 and is in contact with the redistribution layer 108. This allows signals on the redistribution layer 108 to be transmitted through the bump under-metal layer 109, and one bump under-metal layer 109 can be connected to one redistribution layer 108.

[0201] In some embodiments, as shown in Figures 14 and 15, the pressure sensing chip 100 may further include a connector 110. The connector 110 may be, for example, a solder ball. The connector 110 can serve as both an input and output port for the pressure sensing chip 100. The connector 110 is located on the side of the under-bump metal layer 109 away from the substrate 101 and is in contact with the under-bump metal layer 109. This allows signals on the under-bump metal layer 109 to be transmitted to the connector 110. One connector 110 can be connected to one under-bump metal layer 109. The connector 110 can also serve as a bonding structure for connection to a circuit board.

[0202] For example, the signal from the pressure-sensitive structure 104 can be transmitted to the connector 110 via the lead 106, conductive post 107, redistribution layer 108, and under-bump metal layer 109. The connector 110 outputs the signal to the signal processing unit on the circuit board connected to the pressure sensing chip 100.

[0203] For example, the under-bump metal layer 109 can also serve as a bonding layer between the redistribution layer 108 and the connector 110. At the same time, the under-bump metal layer 109 prevents material atoms of the connector 110 (solder ball) from diffusing into the redistribution layer 108, thus affecting the function of the redistribution layer 108.

[0204] On the other hand, an electronic product is provided. The electronic product includes a pressure sensing chip 100 as described in any of the above embodiments and a circuit board, wherein the circuit board is connected to the pressure sensing chip 100.

[0205] For example, a signal processing unit is provided on the circuit board. After the signal of the pressure-sensitive structure 104 is transmitted to the signal processing unit of the circuit board, the pressure value of the external pressure is output after being processed by the signal processing unit.

[0206] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0207] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A pressure sensing chip, comprising: The substrate includes the pressure-sensitive diaphragm. A support layer is disposed on one side of the substrate, and a groove is formed on the surface of the support layer near the substrate, forming a pressure cavity between the groove and the pressure-sensitive diaphragm. A pressure-sensitive structure, wherein at least a portion of the pressure-sensitive structure is embedded on the side surface of the pressure-sensitive diaphragm near the support layer; A portion of the surface of the pressure-sensitive structure is exposed within the pressure chamber; A reinforcing layer is disposed on the side of the support layer away from the substrate.

2. The pressure sensing chip according to claim 1 further comprises: A reinforcing structure is located within the pressure chamber and is connected to the bottom wall of the groove; The orthographic projection of the reinforcing structure onto the substrate does not overlap with the orthographic projection of the pressure-sensitive structure onto the substrate.

3. The pressure sensing chip according to claim 2, wherein, The reinforcing structure is positioned at a distance from the pressure-sensitive diaphragm on its side surface; or... The reinforcing structure is connected to the pressure-sensitive membrane on the side surface closest to it.

4. The pressure sensing chip according to claim 3, wherein, The reinforcing structure is spaced apart from the pressure-sensitive diaphragm on the side surface near the pressure-sensitive diaphragm. Along the thickness direction of the substrate, the distance between the reinforcing structure and the substrate is 1 to 2 times the distance by which the pressure-sensitive diaphragm deforms when the pressure sensing chip is subjected to full-scale pressure.

5. The pressure sensing chip according to claim 3, wherein, The reinforcing structure is connected to the pressure-sensitive membrane on one side, and the position where the reinforcing structure is connected to the pressure-sensitive membrane includes a right angle.

6. The pressure sensing chip according to any one of claims 2 to 5, wherein, Along the thickness direction of the substrate, the centerline of the pressure-sensitive membrane penetrates the reinforcing structure.

7. The pressure sensing chip according to any one of claims 2 to 6, wherein, The reinforcing structure and the supporting layer are integrally formed.

8. The pressure sensing chip according to any one of claims 1 to 7, wherein, The pressure-sensitive structure includes a first capacitor, which includes a first electrode plate and a second electrode plate disposed opposite to each other; the first electrode plate is embedded on the side surface of the pressure-sensitive membrane near the support layer, and the side surface of the first electrode plate away from the pressure-sensitive membrane is exposed in the pressure chamber; the second electrode plate is disposed on the bottom wall of the groove.

9. The pressure sensing chip according to claim 8, wherein, The pressure-sensitive structure further includes a second capacitor, which includes a third electrode plate and a fourth electrode plate disposed opposite to each other; the third electrode plate is embedded on the surface of the pressure-sensitive diaphragm near the support layer, and the surface of the third electrode plate away from the pressure-sensitive diaphragm is exposed in the pressure chamber; the fourth electrode plate is disposed on the bottom wall of the groove. Wherein, the orthographic projection of the first capacitor on the substrate and the orthographic projection of the second capacitor on the substrate do not overlap; along the thickness direction of the substrate, the center line of the pressure-sensitive diaphragm passes through the first capacitor.

10. The pressure sensing chip according to claim 9, wherein, The orthographic projection of the second capacitor onto the substrate is disposed around the outer edge of the orthographic projection of the first capacitor onto the substrate.

11. The pressure sensing chip according to any one of claims 8 to 10, wherein, The substrate also includes a body portion, which is disposed around the pressure-sensitive membrane portion; The pressure sensing chip is provided with a pressure channel, which includes a first part and a second part that are connected to each other. The first part extends through the body and a portion of the support layer, and the second part is disposed within the support layer and located between the pressure chamber and the reinforcing layer; The orthographic projection of the second part onto the substrate covers the orthographic projection of the pressure chamber onto the substrate.

12. The pressure sensing chip according to any one of claims 1 to 7, wherein, The pressure-sensitive structure includes a plurality of pressure-sensitive resistors, which are embedded on the side surface of the pressure-sensitive diaphragm near the support layer.

13. The pressure sensing chip according to any one of claims 1 to 12, wherein, A reference pressure cavity is also provided within the support layer, and the reference pressure cavity is located on the side of the pressure cavity away from the substrate; The pressure sensing chip also includes a reference pressure-sensitive structure, a portion of the surface of which is exposed within the reference pressure chamber, and the reference pressure-sensitive structure is configured to have the same structural type as the pressure-sensitive structure.

14. The pressure sensing chip according to claim 13, wherein, The varistor structure includes a first capacitor, and the reference varistor structure includes a reference capacitor; The reference capacitor includes a first reference plate and a second reference plate disposed opposite to each other; The first reference electrode is disposed on the side surface of the reference pressure chamber away from the substrate, and the second reference electrode is embedded in the support layer on the side of the reference pressure chamber close to the substrate, with the side surface of the second reference electrode away from the substrate exposed inside the reference pressure chamber.

15. The pressure sensing chip according to claim 13, wherein, The pressure-sensitive structure includes a pressure-sensitive resistor, and the reference pressure-sensitive structure includes a reference resistor. The reference resistor is embedded in the support layer on the side of the reference pressure cavity near the substrate, and the surface of the reference resistor on the side away from the substrate is exposed in the reference pressure cavity.

16. The pressure sensing chip according to any one of claims 1 to 15, wherein, The substrate also includes a body portion, which is disposed around the pressure-sensitive membrane portion; The thickness of the body portion is greater than the thickness of the pressure-sensitive membrane portion; or, the thickness of the body portion is equal to the thickness of the pressure-sensitive membrane portion.

17. The pressure sensing chip according to any one of claims 1 to 16, further comprising: Lead wires are embedded in the support layer and connected to the pressure-sensitive structure; A conductive post, penetrating at least a portion of the reinforcing layer and the supporting layer, is connected to the lead wire; A rewiring layer is disposed on the side of the reinforcing layer away from the substrate and connected to the conductive pillar; A connector is attached to the side of the redistribution layer away from the substrate.

18. The pressure sensing chip according to any one of claims 1 to 17, wherein, The material of the support layer includes silicon nitride; and / or, the material of the reinforcing layer includes polycrystalline silicon.

19. An electronic product comprising: The pressure sensing chip as described in any one of claims 1 to 18; The circuit board is connected to the pressure sensing chip.

20. A method for fabricating a pressure sensing chip, comprising: A substrate is provided, the substrate including a pressure-sensitive diaphragm portion; A support layer is formed on one side of the substrate, and a groove is formed on the surface of the support layer near the substrate. A pressure cavity is formed between the groove and the pressure-sensitive diaphragm. At least a portion of the pressure-sensitive structure is embedded on the surface of the pressure-sensitive diaphragm near the support layer, and a portion of the surface of the pressure-sensitive structure is exposed in the pressure cavity. A reinforcing layer is formed on the side of the support layer away from the substrate.

21. The method for fabricating a pressure sensing chip according to claim 20, wherein, A support layer is formed on one side of the substrate, comprising: A sacrificial layer is formed, which covers at least a portion of the pressure-sensitive structure embedded on the side surface of the pressure-sensitive diaphragm near the support layer; A support film is formed, the support film covering the sacrificial layer; At least one through-hole is formed in the portion of the supporting film covering the sacrificial layer, the through-hole exposing the sacrificial layer; The sacrificial layer is removed through the through-hole to form the groove; The through-hole is filled with insulating material to form the support layer.

22. The method for fabricating a pressure sensing chip according to claim 21, wherein, The pressure-sensitive structure includes a first capacitor, which includes a first electrode and a second electrode. Before forming the sacrificial layer, the method for fabricating the pressure sensing chip further includes: The first electrode plate of the pressure-sensitive structure is formed on one side of the pressure-sensitive diaphragm. After forming the sacrificial layer, the method for fabricating the pressure sensing chip further includes: The second electrode of the pressure-sensitive structure is formed on the side of the sacrificial layer away from the substrate.

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