Pressure sensing module, pressure sensor and electronic equipment

Abstract

The present invention provides a pressure sensing module, a pressure sensor, and an electronic device, relating to the field of micro-electromechanical technology, and is used to reduce the effects of thermo-viscoplastic stress and / or thermo-viscoelastic stress introduced by metal traces and / or metal pads on piezoresistors, thereby improving the performance of the pressure sensing module. The pressure sensing module includes: a first substrate structure, a second substrate structure, a plurality of piezoresistors disposed on a surface of a pressure-sensitive film close to the second substrate structure, a plurality of interconnecting metal wires, and a plurality of metal pads; the second substrate structure is located on one side of the first substrate structure; the plurality of interconnecting metal wires are electrically connected to the plurality of piezoresistors so that the plurality of piezoresistors are electrically connected to each other; the metal pads are electrically connected to the first metal wires and also to a readout integrated circuit; wherein at least some of the plurality of interconnecting metal wires are located on the second substrate structure; and / or at least some of the plurality of metal pads are located on the second substrate structure.

Description

Technical Field

[0001] The present application relates to the field of micro-electronic machinery technology, and in particular to a pressure sensing module, a pressure sensor, and an electronic device. Background Art

[0002] Micro-Electro-Mechanical System (MEMS) pressure sensor modules are miniature devices with pressure detection capabilities, manufactured using MEMS technology. They are primarily classified into three types: piezoresistive, capacitive, and resonant. They can be applied to consumer electronics, industrial production, and other fields. Piezoresistive MEMS pressure sensor modules are widely used due to their advantages such as small size, light weight, simple structure, low cost, and high measurement accuracy.

[0003] Existing pressure sensing modules use vertical interconnection through-hole technology for signal extraction, which has high process complexity and causes hysteresis and drift during temperature cycling, affecting the performance of the pressure sensing module. Summary of the Invention

[0004] Embodiments of the present application provide a pressure sensing module, a pressure sensor, and an electronic device. The pressure sensing module is used to reduce the impact of thermo-viscoplastic stress and / or thermo-viscoelastic stress introduced by metal traces and / or metal pads on piezoresistors, thereby improving the performance of the pressure sensing module.

[0005] In a first aspect, the present application provides a pressure sensing module. The pressure sensing module comprises: a first substrate structure, a second substrate structure, a plurality of piezoresistors disposed on a surface of a pressure-sensitive film proximal to the second substrate structure, a plurality of interconnecting metal lines, and a plurality of metal pads; the first substrate structure comprises the pressure-sensitive film; the second substrate structure is located on one side of the first substrate structure; the plurality of interconnecting metal lines are electrically connected to the plurality of piezoresistors so as to electrically connect the plurality of piezoresistors to each other; the metal pads are electrically connected to the interconnecting metal lines and to a readout integrated circuit; at least some of the plurality of interconnecting metal lines are located on the second substrate structure; and / or at least some of the plurality of metal pads are located on the second substrate structure.

[0006] Some embodiments of the present application provide a pressure sensing module, in which a piezoresistor is located on a first substrate structure, and a first metal wire and / or a metal pad is located on a second substrate structure. This allows the WB gold wire to not be directly connected to the active surface where the piezoresistor is located, and the first metal wire to not be directly connected to the piezoresistor. Therefore, the influence of the shell and tube mismatch thermal hysteresis stress / metal trace thermal hysteresis stress on the piezoresistor can be reduced, thereby improving sensor performance.

[0007] In some embodiments, the interconnected metal wires include a first metal wire and a second metal wire, the multiple first metal wires are located on the second substrate structure, and the multiple second metal wires are located on the surface of the first substrate structure close to the second substrate structure; the piezoresistor is connected to the second metal wire, and the second metal wire is connected to the first metal wire, so that the multiple piezoresistors are electrically connected to each other; the first metal wire is electrically connected to the readout integrated circuit; the length of the first metal wire is greater than the length of the second metal wire.

[0008] In some embodiments, the interconnected metal wires include a first metal wire and a second metal wire, the multiple first metal wires and the multiple metal pads are all located on the second substrate structure; the multiple second metal wires are located on the surface of the first substrate structure close to the second substrate structure; the varistor is connected to the second metal wire, and the second metal wire is connected to the first metal wire, so that the multiple varistors are electrically connected to each other; the first metal wire is electrically connected to the metal pad, and the multiple metal pads are also electrically connected to the readout integrated circuit; the length of the first metal wire is greater than the length of the second metal wire.

[0009] In some embodiments, the pressure sensing module further includes: a plurality of first conductive contacts; the plurality of first conductive contacts are disposed between the first substrate structure and the second substrate structure; and the first metal wire and the second metal wire are connected through the first conductive contacts.

[0010] In some embodiments, the multiple first conductive contacts include: multiple first conductive bump groups; the first conductive bump group includes two first conductive bumps, and one first conductive bump of the first conductive bump group is electrically connected to the first end of the varistor through a second metal wire; another first conductive bump of the first conductive bump group is electrically connected to the second end of the varistor through a second metal wire; multiple second conductive bump groups; the second conductive bump group includes two second conductive bumps, the first end of the first metal wire is electrically connected to a second conductive bump of one second conductive bump group, and the second end of the first metal wire is electrically connected to a second conductive bump of another second conductive bump group; the multiple second conductive bump groups are correspondingly connected to the multiple first conductive bump groups, and the multiple varistors, the multiple second metal wires, the multiple first conductive bump groups, the multiple second conductive bump groups and the multiple first metal wires form a ring-shaped Wheatstone bridge structure.

[0011] In some embodiments, the metal pad is electrically connected to the middle end of the first metal wire, and the middle end of the first metal wire is located between the first end and the second end of the first metal wire; the multiple first conductive bumps, the multiple second conductive bumps, the multiple metal pads, the multiple first metal wires and the multiple varistors form a ring-shaped Wheatstone bridge structure.

[0012] In some embodiments, the multiple metal pads include: a third input metal pad; the third input metal pad serves as the input end of the Wheatstone bridge structure; and / or, the multiple metal pads include: a third output metal pad; the third output metal pad serves as the output end of the Wheatstone bridge structure; the third output metal pad is electrically connected to the readout integrated circuit; and / or, the multiple metal pads include: a third ground metal pad; the third ground metal pad serves as the ground end of the Wheatstone bridge structure.

[0013] In some embodiments, the orthographic projections of the multiple piezoresistors on the first substrate structure are located within the region where the pressure-sensitive film is located; and the orthographic projections of the multiple first conductive bump groups on the first substrate structure are located outside the region where the pressure-sensitive film is located.

[0014] In some embodiments, the interconnecting metal line is located on the surface of the first substrate structure close to the second substrate structure; the multiple metal pads are located on the second substrate structure; the interconnecting metal line is connected to the varistors so that the multiple varistors are electrically connected to each other; the interconnecting metal line is connected to the metal pads.

[0015] In some embodiments, the pressure sensing module further includes: a plurality of second conductive contacts; the plurality of second conductive contacts are arranged between the first substrate structure and the second substrate structure; the interconnecting metal line is connected to the metal pad through the second conductive contacts.

[0016] In some embodiments, the pressure sensing module further includes: a welding ring; the welding ring is located between the first substrate structure and the second substrate structure, and the welding ring connects the first substrate structure and the second substrate structure.

[0017] In some embodiments, the pressure sensing module further includes: the pressure sensing module further includes: a plurality of first conductive contacts; the plurality of first conductive contacts are arranged between the first substrate structure and the second substrate structure; the first metal wire and the second metal wire are connected through the first conductive contacts; the orthographic projections of the plurality of first conductive contacts and the plurality of piezoresistors on the plane where the second substrate structure is located are located in the area enclosed by the orthographic projection of the welding ring on the plane where the second substrate structure is located, and the orthographic projections of the plurality of metal pads on the plane where the second substrate structure is located are located outside the orthographic projection of the welding ring on the plane where the second substrate structure is located.

[0018] In some embodiments, the second substrate structure includes: a second lining; the welding ring is arranged on the side of the multiple first metal wires away from the second lining; the pressure sensing module also includes a first insulating layer, the first insulating layer is located on the side of the second lining close to the first substrate structure, and the welding ring is in contact with the surface of the first insulating layer and the surface of the second lining.

[0019] In a case where the interconnection metal lines include first metal lines, the plurality of first metal lines are located on a side of the second liner close to the first substrate structure, and the first insulating layer is located between the first metal lines and the bonding ring.

[0020] In some embodiments, the first substrate structure further includes: a first liner and a buried oxide layer; the buried oxide layer is arranged on the surface of the first liner close to the second substrate structure; the varistor is arranged on the surface of the buried oxide layer away from the first liner; the pressure-sensitive film is in contact with the buried oxide layer; and the welding ring is in contact with the surface of the buried oxide layer.

[0021] The middle part of the first liner is thinned, and the middle part of the first liner and the part of the buried oxide layer facing the middle part of the first liner form the pressure-sensitive film; or, the first liner includes an opening located in the middle, and the part of the buried oxide layer facing the opening of the first liner forms the pressure-sensitive film.

[0022] In some embodiments, the first substrate structure, the second substrate structure, and the welding ring form a vacuum cavity; and the plurality of varistors are located inside the vacuum cavity.

[0023] In some embodiments, the pressure sensing module further includes a getter plate located in the vacuum cavity.

[0024] In a second aspect, some embodiments of the present application provide a pressure sensor, comprising: the above-mentioned pressure sensing module and a readout integrated circuit; the readout integrated circuit is electrically connected to the multiple metal pads.

[0025] The beneficial effects that can be achieved by the pressure sensors provided in some embodiments of the present application are the same as the beneficial effects that can be achieved by the pressure sensing module provided by the above technical solution, and will not be repeated here.

[0026] In a third aspect, some embodiments of the present application provide an electronic device, which includes a housing and a pressure sensor disposed on the housing.

[0027] The beneficial effects that can be achieved by the electronic devices provided by some embodiments of the present application are the same as the beneficial effects that can be achieved by the pressure sensing module provided by the above technical solution, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the embodiments of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the drawings:

[0029] Figure 1 A structural diagram of a pressure sensing module provided in some embodiments of the present disclosure;

[0030] Figure 2 A bottom view of a first substrate structure provided for some embodiments of the present disclosure;

[0031] Figure 3 A structural diagram of another pressure sensing module provided for some embodiments of the present disclosure;

[0032] Figure 4 A side view of a first substrate structure provided for some embodiments of the present disclosure;

[0033] Figure 5 A top view of a second substrate structure provided for some embodiments of the present disclosure;

[0034] Figure 6 A partial enlarged view provided for some embodiments of the present disclosure;

[0035] Figure 7 A structural diagram of another pressure sensing module provided in some embodiments of the present disclosure;

[0036] Figure 8 A cross-sectional view of a pressure sensing module provided in some embodiments of the present disclosure;

[0037] Figure 9 A cross-sectional view of another pressure sensing module provided for some embodiments of the present disclosure;

[0038] Figure 10A structural diagram of a pressure sensor provided in some embodiments of the present disclosure;

[0039] Figure 11 A structural diagram of an electronic device provided for some embodiments of the present disclosure. DETAILED DESCRIPTION

[0040] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the embodiments described are only some embodiments of the present application, not all embodiments. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0041] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as having an open, inclusive meaning, that is, "including, but not limited to." In the description of the specification, the terms "one embodiment," "some embodiments," "exemplary embodiments," "examples," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present application. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials, or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0042] Micro-Electro-Mechanical System (MEMS) pressure sensor modules are miniature devices with pressure detection capabilities, manufactured using MEMS technology. They are primarily classified into three types: piezoresistive, capacitive, and resonant. They can be applied to consumer electronics, industrial production, and other fields. Piezoresistive MEMS pressure sensor modules are widely used due to their advantages such as small size, light weight, simple structure, low cost, and high measurement accuracy.

[0043] A piezoresistive MEMS pressure sensing module includes a pressure-sensitive membrane (also called a strain film), a piezoresistor, and a circuit structure, with the piezoresistor and circuit structure electrically connected. The operating principle of a piezoresistive MEMS pressure sensing module can be described as follows: a piezoresistor is formed on the strain film. The strain film deforms under external pressure, generating stress. The piezoresistor changes its resistance due to the stress. Finally, an interconnected structure (such as a Wheatstone bridge) converts this resistance change into a voltage output. Therefore, the voltage output value can reflect the magnitude of the external pressure.

[0044] In some embodiments, the pressure sensing module is composed of a three-layer structure, including a single crystal silicon protective layer, a single crystal silicon pressure sensitive film and an insulator single crystal silicon thin film (Silicon-On-Insulator, SOI) structure support layer. The three-layer structure makes the upper and lower layers symmetrical, solving the problem of mutual restriction between full-scale output and resonant frequency in the prior art, the inherent contradiction between full-scale output and nonlinearity, and the problem that full-scale output and overload are difficult to improve synchronously. However, this solution uses vertical interconnection through-hole technology to lead out the signal, which has high process complexity, and the interconnection wiring and the varistor are both located on the same active surface, that is, the interconnection wiring is directly connected to the varistor, resulting in the thermal mismatch stress introduced by the metal wiring being transmitted to the varistor, causing hysteresis and drift during temperature cycling. In addition, the varistor of this solution is located in the SOI device layer and is directly exposed to the external environment. During the measurement process, the external environment can easily damage the device or affect the sensor performance.

[0045] In some embodiments, the pressure sensing module utilizes a novel structure in which 4H-SiC body leads partially replace metal circuits, 4H-SiC body leads are etched in the N-type highly doped epitaxial layer, and electrical connection is achieved between the 4H-SiC body leads and the metal wire bonding pads through the ohmic contact area. This replaces the full metal circuit connection between the metal wire bonding pads and the 4H-SiC varistor strips, effectively improving the high-temperature stability of the sensor circuit connection and providing a homogeneous 4H-SiC contact for further direct bonding. However, this solution also uses vertical interconnection through-hole technology for signal extraction, which has high process complexity, and the interconnection traces and the varistor are located on the same active surface, that is, the interconnection traces are directly connected to the varistor, resulting in the thermal mismatch stress introduced by the metal traces being transmitted to the varistor, causing hysteresis and drift during temperature cycling. In addition, the varistor of this solution is located in the SOI device layer and is directly exposed to the external environment. During the measurement process, the external environment can easily damage the device or affect the sensor performance.

[0046] That is to say, the existing pressure sensing module uses vertical interconnection through-hole technology to lead out the signal, which has high process complexity. In addition, the interconnection wiring and the piezoresistor are located on the same active surface, which will cause the thermo-viscoplastic stress and / or thermo-viscoelastic stress introduced by the metal wiring to be transmitted to the piezoresistor, thereby causing hysteresis and drift during temperature cycling.

[0047] Based on this, some embodiments of the present application provide a pressure sensing module. Figure 1 As shown, the pressure sensing module 100 includes a first substrate structure 10 and a second substrate structure 20 .

[0048] The first substrate structure 10 includes a pressure-sensitive film 11 ; the second substrate structure 20 is located on one side of the first substrate structure 10 and connected to the first substrate structure 10 .

[0049] The pressure sensing module 100 further includes a plurality of piezoresistors 12 disposed on a surface of the pressure sensitive film 11 close to the second substrate structure 20 .

[0050] The pressure sensing module 100 further includes: a plurality of interconnecting metal lines 21 and a plurality of metal pads 24 .

[0051] A plurality of interconnecting metal lines 21 are electrically connected to the plurality of varistors 12, so that the plurality of varistors 12 are electrically connected to each other. A metal pad 24 is electrically connected to the interconnecting metal lines 21 and is also electrically connected to the readout integrated circuit.

[0052] Wherein, at least some of the plurality of interconnected metal lines 21 are located on the second substrate structure; and / or at least some of the plurality of metal pads are located on the second substrate structure.

[0053] If only a plurality of interconnecting metal lines 21 can be provided on the second substrate structure, then the plurality of varistors 12 are not connected to each other on the first substrate structure 10. The plurality of varistors 12 are electrically connected to the plurality of interconnecting metal lines 21, and the varistors and the first metal lines are electrically connected alternately, so that the plurality of varistors 12 can be connected in series in sequence and connected end to end to form a ring circuit.

[0054] For example, the first substrate structure 10 includes four varistors 12 , which are sequentially connected in series and connected end to end to form a ring circuit.

[0055] Among them, the four piezoresistors 12 are located at the center positions of the four edges of the piezoresistive film 11 (refer to Figure 2 ), the four resistor film margins remain consistent and the resistor film edge distance L0 is a value between 0-20um, the width of the four varistors 12 is the same as the total length, and the fold number can be 1-10 folds, wherein the upper and lower varistors have the same structural dimensions, and the left and right varistors have the same structural dimensions.

[0056] In some embodiments, the varistor 12 may be a doped silicon varistor, such as a P-type doped silicon varistor or an N-type doped silicon varistor; in other examples, the varistor 12 may be a metal film varistor, and the material of the metal film may be a material with a high piezoresistive strain coefficient, a low material noise factor, and a low resistance temperature coefficient, such as any one or more combinations of NiCr, Pt, FeNi, TiB, TaN, and TiN.

[0057] Exemplarily, the material of the interconnection metal line 21 may be a low resistivity material, such as any one or more combinations of Al, Ti / Al, Au, and Cr / Au, so that a good circuit path can be formed.

[0058] In this way, the varistor 12 is located on the first substrate structure 10, and the interconnecting metal line 21 is located on the second substrate structure 20. Although the varistor 12 and the interconnecting metal line 21 are electrically connected, the two are not on the same active surface, which will cause the thermo-viscoplastic stress and / or thermo-viscoelastic stress introduced by the metal traces to be transmitted to the varistor, thereby preventing hysteresis and drift during temperature cycling.

[0059] If only a plurality of metal pads 24 are provided on the second substrate structure, the WB gold wires can be not directly connected to the active surface where the varistor is located, thereby reducing the influence of the shell mismatch thermal hysteresis stress / metal trace thermal hysteresis stress on the varistor, thereby improving the sensor performance.

[0060] WB gold wire is a technology used in micro-IC packaging to connect micro-ICs to the packaging substrate. Gold wire plays a crucial bonding role in the micro-IC packaging process, securing the lead frame of the micro-IC to the external packaging substrate, thereby encapsulating and protecting the micro-IC. The selection of gold wire is crucial to ensuring the quality of micro-IC packaging, as gold's excellent conductivity, high corrosion resistance, and resistance to oxidation make it the primary bonding material in micro-IC packaging.

[0061] If the second substrate structure is provided with not only a plurality of interconnecting metal wires 21 but also a plurality of metal pads 24, it is possible to achieve that the WB gold wire is not directly connected to the active surface where the varistor is located and the first metal wire is not directly connected to the varistor, thereby reducing the influence of the shell and tube mismatch thermal hysteresis stress / metal trace thermal hysteresis stress on the varistor, thereby improving the sensor performance.

[0062] Some embodiments of the present application provide a pressure sensing module, wherein the piezoresistor 12 is located on the first substrate structure 10, and the interconnecting metal wire 21 and / or the metal pad 24 is located on the second substrate structure 20. This allows the WB gold wire to not be directly connected to the active surface where the piezoresistor is located, and the first metal wire to not be directly connected to the piezoresistor. Therefore, the influence of the shell and tube mismatch thermal hysteresis stress / metal trace thermal hysteresis stress on the piezoresistor can be reduced, thereby improving the sensor performance.

[0063] That is, this application includes three options:

[0064] The first option: Figure 3 As shown, the interconnection metal lines 21 include first metal lines 210 and second metal lines 220 . The plurality of first metal lines 210 are located on the second substrate structure 20 , and the plurality of second metal lines 220 are located on the surface of the first substrate structure 10 close to the second substrate structure 20 .

[0065] The varistor 12 is connected to the second metal wire 220, and the second metal wire 220 is connected to the first metal wire 210, so that multiple varistor 12 are electrically connected to each other; the first metal wire 210 is electrically connected to the readout integrated circuit; the length of the first metal wire 210 is greater than the length of the second metal wire 220.

[0066] Among them, the thermal hysteresis stress of the metal trace is related to the length of the metal trace. The first solution is equivalent to placing most of the metal traces on the second substrate structure, which can greatly reduce the impact of the thermal hysteresis stress of the metal trace on the varistor. At the same time, refer to Figure 3 It can be seen that the first metal wire is electrically connected to the readout integrated circuit through the lead.

[0067] The varistor 12 is located on the first substrate structure 10, and the first metal wire 210 is located on the second substrate structure 20. This allows the WB gold wire to not be directly connected to the active surface where the varistor is located and the first metal wire to not be directly connected to the varistor. This can reduce the impact of the thermal hysteresis stress of the metal trace on the varistor, thereby improving sensor performance.

[0068] The second option: Figure 1 As shown, the interconnection metal lines 21 include first metal lines 210 and second metal lines 220. The plurality of first metal lines 210 and the plurality of metal pads 24 are all located on the second substrate structure; the plurality of second metal lines are located on the surface of the first substrate structure close to the second substrate structure.

[0069] The varistor 12 is connected to the second metal wire 220, and the second metal wire 220 is connected to the first metal wire 210, so that multiple varistors 12 are electrically connected to each other; the first metal wire 210 is electrically connected to the metal pad 24, and the multiple metal pads 24 are also electrically connected to the readout integrated circuit; the length of the first metal wire is greater than the length of the second metal wire.

[0070] The varistor 12 is located on the first substrate structure 10. Not only is the first metal wire 210 located on the second substrate structure 20, but the metal pad 24 is also located on the second substrate structure. This allows the WB gold wire to not be directly connected to the active surface where the varistor is located, and the first metal wire to not be directly connected to the varistor. Therefore, the impact of the shell and tube mismatch thermal hysteresis stress / metal trace thermal hysteresis stress on the varistor can be reduced, thereby improving sensor performance.

[0071] The pressure sensing module further includes: a plurality of first conductive contacts 130 ; the plurality of first conductive contacts 130 are disposed between the first substrate structure 10 and the second substrate structure 20 ; and the first metal wire 210 and the second metal wire 220 are connected via the first conductive contacts.

[0072] That is, for the first solution, the varistor 12 is electrically connected to the first metal line 210 on the second substrate structure 20 through the first conductive contact 130 in the area near the varistor 12, and then electrically connected to the readout integrated circuit through the first metal line 210 on the second substrate structure 20.

[0073] In the second solution, the varistor 12 is electrically connected to the metal pad 24 on the second substrate structure 20 through the first conductive contact 130 in the area near the varistor 12, and the metal pad 24 is electrically connected to the readout integrated circuit through a lead.

[0074] like Figure 3 and Figure 4 As shown, the plurality of first conductive contacts 130 further include: a plurality of first conductive bump groups 13 ; the first conductive bump group 13 includes two first conductive bumps 131 , and the first conductive bump group 13 is electrically connected to the varistor 12 .

[0075] For example, one end of the varistor 12 is electrically connected to one first conductive bump 131 , and the other end of the varistor 12 is electrically connected to another first conductive bump 131 .

[0076] Optionally, the first metal trace 3 may be made of a low resistivity material such as Al, Ti / Al, Au, or Cr / Au to form a good circuit path.

[0077] The multiple first conductive contacts 130 also include: multiple second conductive bump groups 23, the second conductive bump group 23 includes two second conductive bumps 231, the first end of the first metal wire 210 is electrically connected to a second conductive bump 231 of one second conductive bump group 23, and the second end of the first metal wire 210 is electrically connected to a second conductive bump 231 of another second conductive bump group 23.

[0078] The plurality of second conductive bump groups 23 are connected to the plurality of first conductive bump groups 13 correspondingly, and the plurality of varistors 12 , the plurality of first conductive bump groups 13 , the plurality of second conductive bump groups 23 and the plurality of first metal wires 210 form a loop.

[0079] For example, the first bumps and the second bumps are connected correspondingly, that is, the two first bumps of a first bump group are in contact with the two second bumps of a second bump group at corresponding positions, thereby achieving electrical connection.

[0080] By using bump technology, the majority of the metal traces are fabricated on the second substrate structure, and the varistors are connected to form a bridge on the second substrate structure. This eliminates the need for direct metal trace connection to the varistors. This reduces the impact of thermo-viscoplastic and / or thermo-viscoelastic stresses introduced by the metal traces on the varistors, thereby improving sensor performance. Furthermore, compared to vertical interconnect via technology, bump technology offers a simpler process and higher yield.

[0081] In some embodiments, thermal mismatch stress between the package and the varistor is transmitted to the varistor through wire crosstalk in the wire bonding (WB) structure, causing hysteresis and drift during temperature cycling, affecting the performance of the pressure sensing module. Therefore, this application also proposes the following new embodiments.

[0082] like Figure 2 and Figure 4 As shown, the pressure sensing module 100 also includes multiple second metal wires 220; a first conductive bump of the first conductive bump group 13 is electrically connected to the first end of the varistor 12 through a second metal wire 220; another first conductive bump of the first conductive bump group 13 is electrically connected to the second end of the varistor 12 through a second metal wire 220.

[0083] The orthographic projections of the plurality of varistors 12 on the first substrate structure 10 are located within the region where the pressure-sensitive film is located; and the orthographic projections of the plurality of first conductive bump groups on the first substrate structure are located outside the region where the pressure-sensitive film is located.

[0084] In this way, when the pressure sensing module 100 is used, the pressure only acts on the piezoresistor 12 and does not act on the first conductive bump group 13 .

[0085] The first conductive bump group 13 and the varistor 12 are electrically connected via a second metal wire 220. The second metal wire 220 laterally connects the varistor 12 and the first conductive bump group 13. The length of the second metal wire 220 is less than 50 μm, and the width is less than 15 μm. Because the required second metal wire is very small, the thermal mismatch stress introduced by the second metal wire 220 is negligible, thus preventing hysteresis and drift during temperature cycling.

[0086] Reference Figure 1 and Figure 4 , multiple metal pads 24 are electrically connected to the middle end of the first metal wire 210, and the middle end of the first metal wire 210 is located between the first end and the second end of the first metal wire; multiple first conductive bump groups 13, multiple second conductive bump groups 23, multiple metal pads 24, multiple first metal wires 210 and multiple varistors 12 form a ring-shaped Wheatstone bridge structure.

[0087] That is, the ring structure composed of the plurality of first conductive bump groups 13 , the plurality of second conductive bump groups 23 , the plurality of metal pads 24 , the plurality of first metal wires 210 and the plurality of varistors 12 may be equivalent to a Wheatstone bridge structure.

[0088] It should be noted that the first conductive bump group 13 is located outside the varistor 11 and is adjacent to the corresponding varistor 12. The first conductive bumps can be square, rectangular, circular, elliptical, etc., and the side length or diameter L1 of the first conductive bump is 50-100 um.

[0089] Similarly, the second conductive bump group 23 corresponds to the first conductive bump group 13 . The second conductive bumps 231 can be square, rectangular, circular, or elliptical in shape. The side length or diameter L1 ′ of the second conductive bumps 231 is 50-100 μm.

[0090] Optionally, the material of the first conductive bump group 13 may be Au, AuSn, AgSn, CuSn, SnAgCu, etc.

[0091] Optionally, the material of the second conductive bump group 23 may be Au, AuSn, AgSn, CuSn, SnAgCu, etc.

[0092] like Figure 4 As shown, the multiple metal pads 24 include: a third input metal pad 241; the third input metal pad serves as the input end of the Wheatstone bridge structure; and / or, the multiple metal pads 24 include: a third output metal pad 242; the third output metal pad serves as the output end of the Wheatstone bridge structure; the third output metal pad is electrically connected to the readout integrated circuit; and / or, the multiple metal pads 24 include: a third ground metal pad 243; the third ground metal pad serves as the ground end of the Wheatstone bridge structure.

[0093] The Wheatstone bridge structure includes: an input terminal, two output terminals and a ground terminal.

[0094] In some embodiments, the third input metal pad 241 is a metal pad. The third input metal pad serves as the input end of the Wheatstone bridge structure. The Wheatstone bridge structure has three terminals. The plurality of metal pads 24 can continue to be used as two output terminals and a ground terminal of the Wheatstone bridge structure. Alternatively, the metal pads 24 can be directly connected to the case ground by bonding a silicon-aluminum wire on the second substrate structure to achieve grounding, or directly bond a silicon-aluminum wire on the second substrate structure to serve as the output terminal.

[0095] like Figure 4 As shown, the plurality of metal pads 24 include: a plurality of third output metal pads 242; the third output metal pads serve as output ends of the Wheatstone bridge structure.

[0096] In some embodiments, the third output metal pad 242 is a metal pad. The two third output metal pads serve as the two output terminals of the Wheatstone bridge structure. The Wheatstone bridge structure has two terminals. The plurality of metal pads 24 can continue to be used as an input terminal and a ground terminal of the Wheatstone bridge structure. Alternatively, the second substrate structure can be directly connected to the case ground by bonding a silicon aluminum wire on the second substrate structure to achieve grounding, or the second substrate structure can be directly bonded to the silicon aluminum wire on the second substrate structure as an input terminal.

[0097] like Figure 4 As shown, the plurality of metal pads 24 include: a third grounding metal pad 243 ; the third grounding metal pad serves as a grounding end of the Wheatstone bridge structure.

[0098] In some embodiments, the third ground metal pad 243 is a metal pad. The third ground metal pad serves as the ground end of the Wheatstone bridge structure. The Wheatstone bridge structure has three terminals. The plurality of metal pads 24 can continue to be used as two output terminals and one input terminal of the Wheatstone bridge structure. Alternatively, the input terminal can be directly bonded to the second substrate structure using silicon aluminum wire, or the output terminal can be directly bonded to the second substrate structure using silicon aluminum wire.

[0099] It should be noted that the two output terminals of the Wheatstone bridge structure are located at opposite corners, and the positions of the input terminal and the ground terminal are not required. Figure 4 Only one possible case is shown.

[0100] Multiple metal pads 24 are located on the second substrate structure and are arranged outside the tube shell of the pressure sensing module. They can reduce the problem of hysteresis and drift during temperature cycling caused by the thermal mismatch stress of the tube shell being transmitted into the piezoresistor through the lead crosstalk in the WB, thereby improving the performance of the pressure sensing module.

[0101] The metal pad can be square, rectangular, circular, oval or other structures, and the pad side length or straight dimension L1" is 50-150um.

[0102] The third option: Figure 7 As shown, the interconnection metal line 21 is located on a surface of the first substrate structure 10 that is close to the second substrate structure 20 .

[0103] A plurality of metal pads 24 are located on the second substrate structure 20 ; interconnection metal lines 21 are connected to the varistors to electrically connect the plurality of varistors to each other; and interconnection metal lines 21 are connected to the metal pads 24 .

[0104] In this solution, the interconnected metal lines are located on the first substrate structure 10, and the influence of the shell-to-shell mismatch thermal hysteresis stress on the varistor is reduced mainly by adding metal pads on the second substrate structure, thereby improving the sensor performance.

[0105] In some embodiments, the pressure sensing module 100 further includes: a plurality of second conductive contacts 140 ; ​​the plurality of second conductive contacts 140 are disposed between the first substrate structure 10 and the second substrate structure 20 ; and the interconnection metal wires 21 are connected to the metal pads 24 via the second conductive contacts 140 .

[0106] That is to say, for the third solution, a lead wire is set on the first substrate structure 10 to lead the varistor 12 to a position corresponding to the metal pad 24 on the second substrate structure 20 through the second conductive contact 140; wherein, this position is generally farther away from the varistor 12 than the position of the first solution, and then an electrical connection with the readout integrated circuit is achieved through the metal pad.

[0107] In summary, the actual difference between the above three solutions is the starting point from which the contacts are led to the second substrate. To lead out to the farthest position, the metal pad must be placed on the second substrate structure (the third solution) to achieve the technical effect. As long as the position is shortened (the first solution), the performance of the pressure sensing module can be improved by shortening the lead, or the metal pad can be superimposed on the second substrate structure at the same time (the second solution) to further improve the performance of the pressure sensing module.

[0108] In some embodiments, reference Figure 8 and Figure 9 The pressure sensing module 100 further includes a welding ring 30 ; the welding ring is located between the first substrate structure 10 and the second substrate structure 20 , and the welding ring connects the first substrate structure 10 and the second substrate structure 20 .

[0109] Reference Figure 4 The first substrate structure 10 also includes: a first liner 15 and a buried oxide layer 16; the middle portion of the first liner 15 is thinned to form a pressure-sensitive film; the buried oxide layer 16 is arranged on the surface of the first liner close to the second substrate structure; the varistor is arranged on the surface of the buried oxide layer 16 away from the first liner 15; the pressure-sensitive film is in contact with the buried oxide layer 16; and the welding ring is in contact with the surface of the buried oxide layer.

[0110] In some embodiments, the first liner 15 is an SOI substrate layer. The SOI substrate layer can be etched to the buried oxide layer to form a cavity, or a portion of the substrate layer can be etched to form a cavity, and a pressure-sensitive film can be formed inside the cavity. Figure 2 The cavity is a square cavity, and the side length of the cavity can be L2: 500-2000um.

[0111] For example, the first liner 15 may be made of silicon. The buried oxide layer 16 may be made of an insulating material, such as a combination of one or more of SiO 2 , SiN, and glass. The first liner 15 and the buried oxide layer 16 may form an SOI structure.

[0112] For example, Figure 2 As shown, the size of the first liner 15 is consistent with the size of the buried oxide layer 16, and the distance L3 between the outer boundary of the solder ring 30 and the boundary of the buried oxide layer 16 is greater than or equal to 50μm, for example, 50μm, 60μm, 70μm, 75μm, 80μm or 90μm, etc. In this way, the material of the solder ring 30 can be prevented from flowing to the outside of the surface of the buried oxide layer 16 away from the first liner 15 during the packaging process.

[0113] The orthographic projections of the multiple first conductive bump groups, the multiple second conductive bump groups and the multiple varistors on the plane where the second substrate structure is located are located within the area enclosed by the orthographic projection of the welding ring on the plane where the second substrate structure is located, and the orthographic projections of the multiple metal pads on the plane where the second substrate structure is located are located outside the orthographic projection of the welding ring on the plane where the second substrate structure is located.

[0114] That is, the region where the varistor is located is opposite to the region where the pressure sensitive film is located. The orthographic projections of the multiple varistors on the first substrate 15 are located in the region where the pressure sensitive film is located. The welding ring surrounds the multiple varistors, thereby forming a sealed or vacuum structure.

[0115] The second substrate structure 20 further includes: a second liner 25 ; a plurality of first metal wires 210 located on a side of the second liner 25 close to the first substrate structure 10 ; and a solder ring 30 disposed on a side of the plurality of first metal wires 210 away from the second liner 25 .

[0116] The pressure sensing module further includes a first insulating layer 26 . The first insulating layer 26 is located between the first metal wire 210 and the solder ring 30 . The solder ring 30 contacts the surface of the first insulating layer 26 and the surface of the second substrate 25 .

[0117] The first insulating layer 26 is used to isolate the electrical connection between the first metal trace and the solder ring.

[0118] In some embodiments, the second liner 25 is a second insulating layer 252. The second insulating layer is used to prevent the first metal wire from contacting a conductor and preventing the first metal wire from leaking electricity.

[0119] In some embodiments, the second liner 25 is a substrate silicon wafer 251 and a second insulating layer 252. The second insulating layer is located on a side of the silicon wafer close to the first substrate structure.

[0120] The substrate silicon wafer is a conductor, and the second insulating layer is used to isolate the first metal wire from the substrate silicon wafer.

[0121] The solder ring 30 is composed of a first solder ring 31 and a second solder ring 32. The first solder ring 31 is disposed on the surface of the buried oxide layer 16 away from the first substrate 15, with a distance between the varistor 12 and the plurality of first conductive bump groups 13. The second solder ring 32 is disposed on the surface of the first insulating layer 26 away from the second substrate 25, and matches the shape and position of the first solder ring 31. The solder ring 30 is formed by contacting and securing the first and second solder rings 31, for example, using a high-temperature melting process.

[0122] In this case, while the first solder ring 31 and the second solder ring 32 are in contact and fixed, the second conductive bump groups 23 and the first conductive bump groups 13 are in contact and fixed accordingly, thereby achieving electrical connection between the second conductive bump groups 23 and the first conductive bump groups 13 .

[0123] As a possible implementation, the thickness of the first solder ring 31 is equal to the height of the first conductive bump group 13; and the thickness of the second solder ring 32 is equal to the sum of the height of the second conductive bump group 23 and the thickness of the second insulating layer 252. This ensures the bonding strength between the first solder ring 31 and the second solder ring 32, while also ensuring the reliability of the interconnection between the second conductive bump group 23 and the first conductive bump group 13.

[0124] For example, Figure 8 As shown, when the solder ring 30 is composed of a first solder ring 31 and a second solder ring 32, the thickness of the first solder ring 31 and the thickness of the second solder ring 32 can be the same or different. The thickness L4 of the first solder ring 31 can be in the range of 10 μm to 60 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, or 60 μm. The thickness L5 of the second solder ring 32 can be in the range of 10 μm to 60 μm, for example, 10 μm, 21 μm, 30 μm, 40 μm, 50 μm, or 60 μm. In this way, the packaging effect of the first substrate structure 10 and the second substrate structure 20 can be improved.

[0125] For example, Figure 8As shown, when the solder ring 30 is composed of a first solder ring 31 and a second solder ring 32, a distance L6 between the inner edge of the first solder ring 31 and the first conductive bump group 13 is greater than or equal to 50 μm, such as 50 μm, 60 μm, 74 μm, 80 μm, 90 μm, or 100 μm. This ensures that there is no electrical connection between the first solder ring 31 and the first conductive bump group 13. A distance L7 between the inner edge of the second solder ring 32 and the second conductive bump group 23 is greater than or equal to 50 μm, such as 50 μm, 60 μm, 75 μm, 82 μm, 90 μm, or 110 μm. This ensures that there is no electrical connection between the second solder ring 32 and the second conductive bump group 23.

[0126] Exemplarily, the material of the solder ring 30 may be eutectic solder, such as a combination of one or more of AuSn, AgSn, CuSn, and SnAgCu.

[0127] For example, Figure 8 As shown, the width L8 of the solder ring 30 is greater than or equal to 600 μm, such as 600 μm, 650 μm, 700 μm, 750 μm, 810 μm or 900 μm, etc. In this way, the packaging effect of the first substrate structure 10 and the second substrate structure 20 can be improved.

[0128] It should be noted that Figure 8 is Figure 2 、 Figure 5 and Figure 6 The cross-sectional view obtained by splitting the section line Y in . Figure 6 yes Figure 5 Magnified view of area O in FIG.

[0129] The middle portion of the first liner 15 is thinned to form the pressure-sensitive film 11, which contacts the buried oxide layer 16. As a possible implementation, a non-through cavity (e.g., a square-shaped cavity) is provided in the middle portion of the surface of the first liner 15, away from the buried oxide layer 16, thereby thinning the middle portion of the first liner 15 to form the pressure-sensitive film 11. In this way, the pressure-sensitive film 11 and the buried oxide layer 16 in contact therewith can together constitute the pressure-sensing portion of the pressure sensing module 100. This pressure-sensing portion is located close to the piezoresistor 12, thereby improving the accuracy and sensitivity of the pressure sensing module 100.

[0130] The middle portion of the first liner 15 is thinned, and the middle portion of the first liner 15 and the portion of the buried oxide layer 16 facing the middle portion of the first liner 15 form a pressure-sensitive film.

[0131] Alternatively, the first liner 15 includes an opening in the middle, and the portion of the buried oxide layer 16 facing the opening of the first liner 15 forms a pressure-sensitive film.

[0132] In some embodiments, the first substrate structure and the second substrate structure enclose a vacuum cavity; and the plurality of piezoresistors are located inside the vacuum cavity.

[0133] In some embodiments, when the first substrate structure and the second substrate structure are enclosed to form a vacuum cavity, the pressure sensing module further includes a getter sheet located in the vacuum cavity.

[0134] As can be understood, by including the solder ring 30 in the pressure sensing module 100, the first substrate structure 10, the second substrate structure 20, and the solder ring 30 can enclose a main cavity N. Consequently, when the pressure-sensitive film 11 senses pressure changes, it generates stress in response to the pressure and transmits the stress to the piezoresistor 12, thereby achieving the pressure measurement function. Furthermore, this improves the feasibility of packaging the first substrate structure 10 and the second substrate structure 20.

[0135] In some embodiments, as Figure 2 As shown, the first substrate structure 10 and the second substrate structure 20 enclose a vacuum cavity N1 ; a plurality of varistors 12 are located inside the vacuum cavity N1 .

[0136] For example, when the pressure sensing module 100 further includes a solder ring 30 , the first substrate structure 10 , the second substrate structure 20 , and the solder ring 30 enclose a vacuum chamber N1 .

[0137] It can be understood that the vacuum cavity N1 is the aforementioned main cavity N. Moreover, when the first substrate structure 10 and the second substrate structure 20 enclose the vacuum cavity N1, the pressure sensing module 100 is an absolute pressure sensing module, which can measure the absolute value of the pressure change and has the advantages of high precision and a large measurement range.

[0138] Through flip-chip interconnection vacuum packaging technology, the first substrate structure 10 and the second substrate structure 20 are bonded to form a vacuum cavity. The varistor is located inside the vacuum cavity. There is no need to use silicone oil protection to simplify the process, improve sensor performance, and avoid interference from the external environment.

[0139] In some embodiments, as Figure 1 、 Figure 4 and Figure 9 As shown, when the first substrate structure 10 and the second substrate structure 20 enclose a vacuum cavity N1 , the pressure sensing module 100 further includes a getter sheet 40 located in the vacuum cavity N1 .

[0140] For example, Figure 1 、 Figure 4 and Figure 9As shown, the getter sheet 40 is a square getter sheet disposed on a surface of the first insulating layer 26 away from the second liner 25. Furthermore, the area of ​​the getter sheet 40 is smaller than the area of ​​the pressure-sensitive film 11. In some examples, the geometric center of the getter sheet 40 is collinear with the geometric center of the pressure-sensitive film 11.

[0141] For example, Figure 1 and Figure 5 As shown, when the getter sheet 40 is disposed on a surface of the first insulating layer 26 away from the second liner 25, the distance L10 between the second conductive bump 231 closest to the getter sheet 40 and the getter sheet 40 is greater than or equal to 50 μm, such as 50 μm, 60 μm, 70 μm, 75 μm, 80 μm, or 100 μm. This prevents the getter sheet 40 and the second conductive bump 231 from connecting with each other during use of the pressure sensing module 100, thereby preventing the module from being used poorly.

[0142] It can be understood that since the pressure sensing module 100 also includes an air-absorbing sheet 40 located in the vacuum cavity N1, the air-absorbing sheet 40 can be used to absorb the gas that may enter the vacuum cavity N1 during the use of the pressure sensing module 100, so that the vacuum cavity N1 maintains a high vacuum degree.

[0143] Here, there is no limitation on the material of the getter sheet 40 , as long as it can absorb the gas that may enter the vacuum chamber N1 during use of the pressure sensing module 100 and maintain the vacuum level of the vacuum chamber N1 .

[0144] In summary, by utilizing bump technology and lateral wafer routing, the majority of the metal routing structure is fabricated on the secondary substrate structure. The varistors are then connected to form a bridge on this secondary substrate structure. This eliminates the need for direct metal routing to the varistors, thereby reducing the impact of thermal hysteresis stress on the varistors and improving sensor performance. Furthermore, bump technology and lateral wafer routing offer a simpler process and higher yield compared to vertical interconnect via technology.

[0145] Through flip-chip interconnection vacuum packaging technology, the first substrate structure and the second substrate structure form a vacuum cavity. The varistor is located inside the vacuum cavity, eliminating the need for silicone oil protection to simplify the process, improve sensor performance, and avoid interference from the external environment.

[0146] The above-mentioned pressure sensing module 100 is an absolute pressure sensing module, which can measure the absolute value of pressure changes and has the advantages of high accuracy and a large measurement range. However, the absolute pressure sensing module is not suitable for some measurements related to water pressure and air pressure. Therefore, a gauge pressure sensing module is proposed as follows:

[0147] like Figure 9As shown, in some embodiments, a through hole 50 is opened in the middle of the second lining 25; the first substrate structure 10 and the second substrate structure 20 enclose a gauge pressure cavity N2; and a plurality of varistors 12 are located inside the gauge pressure cavity N2.

[0148] Here, there is no limitation on the size of the through hole 50. In some examples, such as Figure 6 As shown, the aperture L11 of the through hole 50 ranges from 0 to 100 μm, for example, 0 μm, 10 μm, 30 μm, 50 μm, 70 μm or 100 μm.

[0149] For example, a third insulating layer (not shown in the figure) may be provided on the sidewall of the through hole, thereby improving the safety and reliability of the pressure sensing module.

[0150] It can be understood that the gauge pressure cavity N2 is the aforementioned main cavity N. The through hole 50 can be used to connect the gauge pressure cavity N2 to the external atmospheric environment, so that the pressure of the gauge pressure cavity N2 is equal to the external pressure. Moreover, when the first substrate structure 10 and the second substrate structure 20 are enclosed to form the gauge pressure cavity N2, the pressure sensing module 100 is a gauge pressure type pressure sensing module, which can be measured with atmospheric pressure as a reference object. It has the advantage of being easy to prepare and can be used to measure the relative pressure change values ​​of media such as water pressure and air pressure.

[0151] like Figure 10 As shown, some embodiments of the present disclosure further provide a pressure sensor 200. The pressure sensor 200 includes a pressure sensing module 100 and a readout integrated circuit 150 provided by the above technical solution. The readout integrated circuit 150 is electrically connected to the two third output metal pads 242 of the pressure sensing module 100.

[0152] The beneficial effects that can be achieved by the pressure sensor 200 provided in some embodiments of the present disclosure are the same as the beneficial effects that can be achieved by the pressure sensing module 100 provided by the above technical solution, and will not be repeated here.

[0153] It is understood that when the piezoresistor 12 receives pressure, it generates a voltage signal and transmits the voltage signal to the readout integrated circuit 150. The readout integrated circuit 150 can further process the voltage signal and output it as a digital signal to feedback the pressure. In this way, the transmission of pressure measurement data can be achieved.

[0154] like Figure 11 As shown, some embodiments of the present disclosure further provide an electronic device 300 . The electronic device 300 includes a housing 310 and a pressure sensor 200 disposed on the housing 310 .

[0155] The beneficial effects that can be achieved by the electronic device 300 provided in some embodiments of the present disclosure are the same as the beneficial effects that can be achieved by the pressure sensor 200 provided by the above technical solution, and will not be repeated here.

[0156] In some examples, the electronic device 300 may be a mobile phone, a computer, or a portable electronic device, so that the pressure sensing module 100 can be applied to technical scenarios such as automobiles and process production that require pressure measurement.

[0157] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A pressure sensing module, characterized in that: include: a first substrate structure including a pressure-sensitive film; a second substrate structure, located on one side of the first substrate structure; a plurality of piezoresistors disposed on a surface of the pressure-sensitive film close to the second substrate structure; a plurality of interconnecting metal lines, the plurality of interconnecting metal lines being electrically connected to the plurality of varistors so as to electrically connect the plurality of varistors to each other; a plurality of metal pads, the metal pads being electrically connected to the interconnect metal lines and also electrically connected to a readout integrated circuit; At least part of the plurality of interconnected metal lines is located on the second substrate structure.

2. The pressure sensing module according to claim 1, wherein: The interconnection metal lines include first metal lines and second metal lines, a plurality of first metal lines are located on the second substrate structure, and a plurality of second metal lines are located on a surface of the first substrate structure close to the second substrate structure; The piezoresistors are connected to the second metal wires, which are connected to the first metal wires, so that the plurality of piezoresistors are electrically connected to each other; the first metal wires are electrically connected to the readout integrated circuit; The length of the first metal wire is greater than the length of the second metal wire.

3. The pressure sensing module according to claim 1, wherein: The interconnection metal lines include first metal lines and second metal lines, and the plurality of first metal lines and the plurality of metal pads are all located on the second substrate structure; A plurality of second metal lines are located on a surface of the first substrate structure close to the second substrate structure; The piezoresistors are connected to the second metal wires, which are connected to the first metal wires, so that the plurality of piezoresistors are electrically connected to each other; the first metal wires are electrically connected to the metal pads, and the plurality of metal pads are also electrically connected to the readout integrated circuit; The length of the first metal wire is greater than the length of the second metal wire.

4. The pressure sensing module according to claim 2 or 3, characterized in that: The pressure sensing module further includes: a plurality of first conductive contacts; the plurality of first conductive contacts are disposed between the first substrate structure and the second substrate structure; The first metal line and the second metal line are connected through the first conductive contact.

5. The pressure sensing module according to claim 4, characterized in that: The plurality of first conductive contacts include: a plurality of first conductive bump groups; the first conductive bump group includes two first conductive bumps, one first conductive bump of the first conductive bump group is electrically connected to the first end of the varistor through a second metal line; another first conductive bump of the first conductive bump group is electrically connected to the second end of the varistor through a second metal line; a plurality of second conductive bump groups; the second conductive bump group includes two second conductive bumps, the first end of the first metal wire is electrically connected to a second conductive bump of one second conductive bump group, and the second end of the first metal wire is electrically connected to a second conductive bump of another second conductive bump group; The plurality of second conductive bump groups are connected correspondingly to the plurality of first conductive bump groups, and the plurality of varistors, the plurality of second metal wires, the plurality of first conductive bump groups, the plurality of second conductive bump groups and the plurality of first metal wires form a ring-shaped Wheatstone bridge structure.

6. The pressure sensing module according to claim 5, characterized in that: The metal pad is electrically connected to a middle end of the first metal line, and the middle end of the first metal line is located between the first end and the second end of the first metal line.

7. The pressure sensing module according to claim 6, characterized in that: The plurality of metal pads include: a third input metal pad; the third input metal pad serves as an input end of the Wheatstone bridge structure; And / or, the plurality of metal pads include: a third output metal pad; the third output metal pad serves as an output end of the Wheatstone bridge structure; the third output metal pad is electrically connected to the readout integrated circuit; And / or, the plurality of metal pads include: a third grounding metal pad; the third grounding metal pad serves as a grounding end of the Wheatstone bridge structure.

8. The pressure sensing module according to claim 5, characterized in that: The orthographic projections of the plurality of piezoresistors on the first substrate structure are located in the area where the piezoresistive film is located; The orthographic projections of the plurality of first conductive bump groups on the first substrate structure are located outside the area where the pressure-sensitive film is located.

9. The pressure sensing module according to claim 1, wherein: The interconnecting metal line is located on a surface of the first substrate structure close to the second substrate structure; The plurality of metal pads are located on the second substrate structure; The interconnecting metal lines are connected to the varistors so as to electrically connect the plurality of varistors to each other; The interconnection metal line is connected to the metal pad.

10. The pressure sensing module according to claim 9, characterized in that: The pressure sensing module further includes: a plurality of second conductive contacts; the plurality of second conductive contacts are arranged between the first substrate structure and the second substrate structure; The interconnection metal line is connected to the metal pad through the second conductive contact.

11. The pressure sensing module according to any one of claims 1 to 3, 9 and 10, characterized in that: The pressure sensing module further includes: a welding ring; the welding ring is located between the first substrate structure and the second substrate structure, and the welding ring connects the first substrate structure and the second substrate structure.

12. The pressure sensing module according to claim 11, wherein: The pressure sensing module further includes: a plurality of first conductive contacts; the plurality of first conductive contacts are disposed between the first substrate structure and the second substrate structure; The first metal line and the second metal line are connected via the first conductive contact; The orthographic projections of the multiple first conductive contacts and the multiple varistors on the plane where the second substrate structure is located are located within the area enclosed by the orthographic projection of the welding ring on the plane where the second substrate structure is located, and the orthographic projections of the multiple metal pads on the plane where the second substrate structure is located are located outside the orthographic projection of the welding ring on the plane where the second substrate structure is located.

13. The pressure sensing module according to claim 11, wherein: The second substrate structure includes: a second liner; the welding ring is arranged on a side of the plurality of first metal wires away from the second liner; The pressure sensing module further includes a first insulating layer, the first insulating layer being located on a side of the second liner close to the first substrate structure, the welding ring being in contact with a surface of the first insulating layer and a surface of the second liner; In a case where the interconnection metal lines include first metal lines, the plurality of first metal lines are located on a side of the second liner close to the first substrate structure, and the first insulating layer is located between the first metal lines and the bonding ring.

14. The pressure sensing module according to claim 11, wherein: The first substrate structure comprises: a first lining; A buried oxide layer is provided on a surface of the first liner close to the second substrate structure; the varistor is provided on a surface of the buried oxide layer away from the first liner; the varistor is in contact with the buried oxide layer; and the solder ring is in contact with a surface of the buried oxide layer. The middle portion of the first liner is thinned, and the middle portion of the first liner and the portion of the buried oxide layer facing the middle portion of the first liner form the pressure-sensitive film; Alternatively, the first liner includes an opening in the middle, and a portion of the buried oxide layer facing the opening of the first liner forms the pressure-sensitive film.

15. The pressure sensing module according to claim 11, wherein: The first substrate structure, the second substrate structure, and the welding ring form a vacuum cavity; the multiple varistors are located inside the vacuum cavity.

16. The pressure sensing module according to claim 15, characterized in that: The pressure sensing module further includes an air getter plate located in the vacuum cavity.

17. A pressure sensor, characterized in that: The pressure sensing module according to any one of claims 1 to 16 further comprises: A readout integrated circuit is electrically connected to the plurality of metal pads.

18. An electronic device, characterized in that: The device comprises a housing and the pressure sensor according to claim 17 which is arranged on the housing.

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