pressure sensor

Abstract

The shield member (20) is composed of a shield portion (20A) located directly above the signal processing electronic circuit portion of the sensor chip (16) provided in the recessed chip setting portion of the sensor chip / terminal fixing member (14), a fixed end portion (20B) connected to one end of the shield portion (20A) and fixed to the sensor chip / terminal fixing member (14), and a fixed end portion (20C) connected to the other end of the shield portion (20A) and fixed to the sensor chip / terminal fixing member (14). The shield portion (20A) is disposed at a position closer to the surface of the sensor chip (16) than the position of the bent portion of the plurality of bonding wires (Wi) at one end of the plurality of bonding wires (Wi) facing each other in the width direction of the shield portion (20A) and connected to the sensor chip (16).

Description

Technical Field

[0001] This invention relates to a pressure sensor. Background Technology

[0002] For example, as shown in Patent Document 1, the sensor unit of the built-in liquid-sealed semiconductor pressure sensor is configured to include the following components as main elements: a metal diaphragm that isolates the pressure chamber connected to the port of the connector component from the liquid-sealed chamber described below; a liquid-sealed chamber formed above the metal diaphragm in the inner periphery of the cylindrical housing, which stores silicone oil as the pressure transmission medium; a sensor chip disposed in the liquid-sealed chamber, which detects pressure changes of the silicone oil via the metal diaphragm; a sensor chip mounting component that supports the sensor chip; a sealing glass that seals the area around the sensor chip mounting component in the inner periphery of the housing; and an input / output terminal group fixed by the sealing glass, which sends output signals from the sensor chip and supplies power to the sensor chip.

[0003] In addition to the above structure, as shown in Figure 1 of Patent Document 1, a shielding member is provided in the liquid-sealed chamber to cut off the unwanted electric field for the signal processing electronic circuitry of the sensor chip. The portion of the shielding member with a gate-shaped cross-section covering the entire sensor chip has a predetermined gap between it and the end face of the sensor chip. The two fixed ends of the shielding member with the gate-shaped cross-section are closely joined to the outer periphery of the sensor chip in one end face of a disk-shaped conductive plate, thus establishing electrical connection. The potential of the shielding member and the conductive plate becomes the same as the potential of the electronic circuitry mounted on the sensor chip.

[0004] In such a structure, because the shielding component with a gate-shaped cross-section covers the entire sensor chip, the volume of the liquid-sealed chamber is relatively large, and sometimes the volume of silicone oil that can be filled in the liquid-sealed chamber is also relatively large. In this case, there is a concern that the output characteristics of the pressure sensor may change due to variations in the metal diaphragm, which are caused by the expansion and contraction of the silicone oil based on changes in ambient temperature. Therefore, as shown in Patent Document 2, to suppress the changes in the output characteristics of the pressure sensor caused by the expansion and contraction of the silicone oil based on changes in ambient temperature due to variations in the metal diaphragm, an annular component that engages with the conductive plate is provided in the liquid-sealed chamber in a way that minimizes the volume of silicone oil filled in the liquid-sealed chamber. That is, the volume of silicone oil filled in the liquid-sealed chamber is smaller than the total internal volume of the liquid-sealed chamber formed by the inner periphery of the housing without the annular component due to the shielding component and the annular component.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-100807

[0008] Patent Document 2: Japanese Patent Application Publication No. 2019-100808

[0009] Patent Document 3: Japanese Patent Application Publication No. 2017-194401 Summary of the Invention

[0010] In order to further suppress changes in the output characteristics of the pressure sensor caused by changes in ambient temperature, it is desirable to further reduce the volume of silicone oil filled in the aforementioned liquid-sealed chamber.

[0011] However, as shown in Patent Document 1, in the structure where the fixed end of the shielding member disposed in the liquid-sealed chamber is fixed to the end face of the conductive plate supported by one end face of the sealed glass, since the structure utilizes the shielding member to cover the entire sensor chip from above the bonding leads, it is necessary to deepen the liquid-sealed chamber, and the volume of the liquid-sealed chamber tends to increase. Furthermore, in the structures shown in Patent Documents 1 and 2, a conductive plate is needed to fix the shielding member, and the liquid-sealed chamber needs to be deepened, which limits the ability to ensure a predetermined gap between the metal diaphragm and the shielding member and to further reduce the internal dimensions of the liquid-sealed chamber along the axial direction of the input / output terminals.

[0012] Considering the above problems, the object of the present invention is to provide a pressure sensor that can provide a shielding component in the liquid-sealed chamber in order to cut off the unwanted electric field for the signal processing electronic circuit of the sensor chip, and can further reduce the volume of silicone oil filled in the liquid-sealed chamber.

[0013] To achieve the above objectives, the pressure sensor of the present invention is characterized by comprising a sensor unit and an electric field cutoff member. The sensor unit includes a sensor chip that detects pressure and sends a detection output signal, a diaphragm that separates a liquid-sealed chamber in which the sensor chip is disposed and a pressure chamber facing the liquid-sealed chamber, an input / output terminal group electrically connected to the sensor chip via wiring material, and a sensor chip / terminal support member having a chip mounting portion in which the sensor chip is disposed and supporting the sensor chip and the input / output terminal group. The electric field cutoff member is disposed between one end face of the sensor chip in the liquid-sealed chamber and the diaphragm, and has a shielding portion located directly above the sensor chip, and a fixed end connected to the shielding portion and fixed to the sensor chip / terminal support member, and cuts off the electric field acting on the sensor chip. At least one end of the wiring material of the shielding portion of the electric field cutoff member connected to the sensor chip along the arrangement direction of the connection end is disposed closer to the center of the sensor chip than the position directly above the wiring material.

[0014] Furthermore, the pressure sensor of the present invention is characterized by comprising a sensor unit and an electric field cutoff member. The sensor unit includes a sensor chip that detects pressure and sends out a detection output signal, a diaphragm that separates a liquid-sealed chamber in which the sensor chip is disposed and a pressure chamber facing the liquid-sealed chamber, an input / output terminal group electrically connected to the sensor chip, and a sensor chip / terminal support member having a chip setting portion in which the sensor chip is disposed and supporting the sensor chip and the input / output terminal group. The electric field cutoff member is disposed between one end face of the sensor chip in the liquid-sealed chamber and the diaphragm, and has a shielding portion located directly above the sensor chip, and a fixed end connected to the shielding portion and fixed to the sensor chip / terminal support member, and cuts off the electric field acting on the sensor chip. The diaphragm has a portion opposite to the shielding portion of the electric field cutoff member, and the two ends of the portion opposite to the shielding portion are connected to each other in a concentric circle and formed with concave and convex shapes that extend toward the sensor chip / terminal support member.

[0015] Furthermore, the pressure sensor of the present invention is characterized by comprising a sensor unit and an electric field cutoff member. The sensor unit includes a sensor chip that detects pressure and sends a detection output signal, a diaphragm that separates a liquid-sealed chamber in which the sensor chip is disposed and a pressure chamber facing the liquid-sealed chamber, an input / output terminal group electrically connected to the sensor chip, and a sensor chip / terminal support member having a chip mounting portion in which the sensor chip is disposed and supporting the sensor chip and the input / output terminal group. The electric field cutoff member is disposed between one end face of the sensor chip in the liquid-sealed chamber and the diaphragm, and has a shielding portion located directly above the sensor chip, and a fixed end connected to the shielding portion and fixed to the sensor chip / terminal support member, and cuts off the electric field acting on the sensor chip. The outer edge of the diaphragm is positioned closer to the end of the sensor chip / terminal support member in the liquid-sealed chamber than the portion facing one end face of the sensor chip. Preferably, the chip mounting portion is formed concavely at the end of the sensor chip / terminal support member.

[0016] Preferably, the conductor pattern is formed on the end face of the support component for the sensor chip / terminal, the input and output terminal groups are electrically connected to the conductor pattern, and each fixed end of the electric field cutting component is fixed to the conductor pattern.

[0017] Furthermore, the pressure sensor of the present invention is characterized by comprising a sensor unit, a pad member, and an electric field cut-off member. The sensor unit includes a sensor chip that detects pressure and sends out a detection output signal, a diaphragm that separates a liquid-sealed chamber in which the sensor chip is disposed and a pressure chamber facing the liquid-sealed chamber, and an input / output terminal group electrically connected to the sensor chip. The pad member is configured to surround the sensor chip in the liquid-sealed chamber. The electric field cut-off member is disposed between one end face of the sensor chip in the liquid-sealed chamber and the diaphragm by being supported by the pad member, and cuts off the electric field acting on the sensor chip. The potential of the electric field cut-off member is set to be the same as the potential of any one of the input / output terminals in the input / output terminal group.

[0018] Preferably, the electric field cut-off component has at least one opening that allows communication between the portion of the liquid seal chamber formed between the diaphragm and the electric field cut-off component and the portion of the inner periphery of the liner component surrounded by the electric field cut-off component, or between the inner side of the liner component and the portion formed between the diaphragm and the electric field cut-off component.

[0019] According to the pressure sensor of the present invention, since at least one end of the wiring material connected to the sensor chip along the arrangement direction of the connection end of the shielding portion of the electric field cutting-off member is positioned closer to the center of the sensor chip than directly above the connection end of the wiring material, an electric field cutting-off member as a shielding member can be provided in the liquid-sealed chamber to cut off the electric field that is undesirable to the signal processing electronic circuit section of the sensor chip, and the volume of silicone oil filled in the liquid-sealed chamber can be further reduced. As a result, the actual filling volume of silicone oil, i.e., the amount of pressure transmission medium such as silicone oil, can be reduced, thereby suppressing the change in the output characteristics of the pressure sensor caused by the change in the displacement of the metal diaphragm, wherein the change in the displacement of the metal diaphragm is caused by the expansion and contraction of the silicone oil based on the change in ambient temperature, thereby improving the temperature characteristics in the output of the pressure sensor. Attached Figure Description

[0020] Figure 1A This is a partial cross-sectional view showing the main parts of the sensor unit and the connector components used in an example of the pressure sensor of the present invention.

[0021] Figure 1B From Figure 1A The arrow IB shown indicates the direction of the observed electric field shielding component configured within the liquid-sealed chamber in a directional view.

[0022] Figure 2 It is shown in Figure 1A Another example of a diaphragm used in the sensor unit shown, and a cross-sectional view of the main part of the sensor unit.

[0023] Figure 3A It is shown in Figure 1A Another example of a diaphragm used in the sensor unit shown, and a cross-sectional view of the main part of the sensor unit.

[0024] Figure 3B It is shown in Figure 1A Another example of a diaphragm used in the sensor unit shown, and a cross-sectional view of the main part of the sensor unit.

[0025] Figure 4A This is a partial cross-sectional view showing an example of a chip mounting section for fixing components to a sensor chip / terminal.

[0026] Figure 4B This is a partial cross-sectional view showing an example of a chip mounting section for fixing components to a sensor chip / terminal.

[0027] Figure 4C This is a partial cross-sectional view showing an example of a chip mounting section for fixing components to a sensor chip / terminal.

[0028] Figure 5A This is a cross-sectional view showing the main part of the sensor unit used in another example of the pressure sensor of the present invention.

[0029] Figure 5B From Figure 5A The arrow VB shown indicates the direction of the observed electric field shielding component configured within the liquid-sealed chamber.

[0030] Figure 6A This is a cross-sectional view showing the main part of the sensor unit used in another example of the pressure sensor of the present invention.

[0031] Figure 6B From Figure 6A The arrow VIB shown indicates the direction of the observed electric field shielding component configured within the liquid-sealed chamber in a directional view. Detailed Implementation

[0032] Figure 1A and Figure 1B The main part of the sensor unit used in an example of the pressure sensor of the present invention is shown.

[0033] The pressure sensor is configured to include: a connector 2, for example, as shown in Patent Document 1, which is connected to a piping for guiding fluid to detect pressure; and a sensor unit housing, which is connected to the base plate 4 of the connector 2 by brazing or the like, housing the sensor unit and supplying the detection output signal from the sensor chip to a predetermined pressure measuring device.

[0034] like Figure 1AAs shown, the metal connector 2 has an internal thread 2fs on its inner side that engages with the external thread of the aforementioned piping connection. The internal thread 2fs communicates with a port 2a of the connector 2, which guides fluid supplied from the direction indicated by arrow P to the pressure chamber 4A described below. One open end of the port 2a faces the opening of the pressure chamber 4A formed between the base plate 4 of the connector 2 and the diaphragm 32 of the sensor unit.

[0035] The outer contour of the sensor unit housing is formed by a cylindrical waterproof housing 6, which serves as a cover. An opening is formed at the lower end of the resin waterproof housing 6. The periphery of the opening, which is the inner side, engages with the periphery of the base plate 4 of the connector component 2. Fluid pressure is introduced into the pressure chamber 4A through the port 2a of the connector component 2. The lower end face of the sensor unit housing 12 is connected to the periphery of the base plate 4 by welding.

[0036] like Figure 1A As shown, the sensor unit that detects the pressure in the pressure chamber 4A formed between the base plate 4 and the diaphragm 32 described below and sends out a detection output signal is configured to include the following components as main elements: a cylindrical metal housing 12; a metal diaphragm 32 that isolates the pressure chamber 4A from the inner periphery of the housing 12; a sensor chip 16 having a plurality of pressure sensing elements and a signal processing electronic circuit that processes signals from the pressure sensing elements; and a sensor chip / terminal fixing member 14 that supports the sensor chip 16 in a concave chip setting portion 14G via an adhesive layer 50, and fixes an input / output terminal group 40ai (i = 1 to 8) electrically connected to the sensor chip 16 and a filling oil pipe 44 (see reference) on the inner periphery of the housing 12. Figure 1B ).

[0037] The diaphragm 32 is supported on one of the lower end faces of the housing 12, which faces the pressure chamber 4A. A diaphragm protective cover 34, which protects the diaphragm 32 disposed in the pressure chamber 4A, has multiple through holes. The periphery of the diaphragm protective cover 34 is welded together with the periphery of the diaphragm 32 to the lower end face of the housing 12. The housing 12, the diaphragm 32, the aforementioned base plate 4, and the connector component 2 are connected and conductive, thereby achieving the same potential. Furthermore, the input / output terminal group 40ai is held insulated from the housing 12 via a sensor chip / terminal fixing component 14 (insulator). The sensor chip / terminal fixing component 14 is formed of, for example, any of the following materials: PPS, POE resin, sealing glass, or ceramic.

[0038] The liquid-sealed chamber 13, formed between the metal diaphragm 32 and the face-to-face sensor chip 16 and sensor chip / terminal fixing member 14, is filled with a predetermined amount of pressure transmission medium PM, such as silicone oil or a fluorinated inert liquid. Furthermore, after filling with oil, one end of the oil-filling tube 44 is flattened and sealed.

[0039] The input / output terminal group 40ai (i = 1 to 8) consists of two power supply terminals (one of which is a GND terminal: a zero (V) terminal), one output terminal, and five adjustment terminals. The two ends of each terminal protrude from one end face of the sensor chip / terminal fixing member 14 along the central axis of the sensor chip / terminal fixing member 14 toward the liquid-sealed chamber 13, or protrude outward from the other end face of the sensor chip / terminal fixing member 14. Furthermore, Figure 1A Only four of the eight terminals are shown in the diagram. The input / output terminal group 40ai is connected to the sensor chip 16 described below via bonding leads Wi, which are used as wiring material.

[0040] The sensor chip 16 is configured to include: a semiconductor strain section having multiple pressure sensing elements forming a bridge circuit on the upper part of a silicon diaphragm portion, for example, formed from silicon in a generally rectangular shape; and an electronic circuit section formed around the pressure sensing elements in the upper surface of the semiconductor strain section, and integrating an amplification circuit, a line correction circuit, a temperature correction circuit, and a correction data holding circuit for processing the output signal of the bridge circuit. Furthermore, the semiconductor strain section and the electronic circuit section can also be separate, independent components.

[0041] As in Figure 4C As shown in the enlarged view, the sensor chip 16 is bonded, for example, to the bottom of the chip mounting portion 14G within the sensor chip / terminal fixing member 14, which forms the inner side of the liquid-sealed chamber 13, via an adhesive layer 50. At this time, one end face of the sensor chip 16 protrudes from the chip mounting portion 14G toward the liquid-sealed chamber 13, extending beyond the end face of the sensor chip / terminal fixing member 14. The depth of the chip mounting portion 14G is, for example, set to approximately 0.3 mm. The protrusion height Ha of one end of the input / output terminal group 40ai, connected via the bonding lead Wi, is, for example, approximately 0.2 mm. Therefore, one end face of the input / output terminal group 40ai is positioned closer to the end face of the sensor chip / terminal fixing member 14 than the aforementioned end face of the sensor chip 16.

[0042] like Figure 1BAs shown, a shielding member 20, serving as an electric field cut-off component, is provided between one end face of the sensor chip 16 and the diaphragm 32 within the liquid-sealed chamber 13. The shielding member 20 cuts off the electric field that is undesirable to the signal processing electronic circuitry of the sensor chip 16. The shielding member 20 is made in a strip shape using conductive metal materials such as stainless steel, copper, or aluminum.

[0043] like Figure 1B As shown, the strip-shaped shielding member 20 is composed of the following components: a shielding portion 20A, which is located directly above the signal processing electronic circuit section of the sensor chip 16; a fixed end portion 20B, which is connected to one end of the shielding portion 20A; and a fixed end portion 20C, which is connected to the other end of the shielding portion 20A. The width of the shielding portion 20A is set to be slightly smaller than one side of the sensor chip 16. (As shown in...) Figure 4C As shown in the enlarged view, the shielding portion 20A is disposed between one end of a plurality of bonding leads Wi and is close to the surface of the sensor chip 16 with a predetermined gap. The plurality of bonding leads Wi are connected to the sensor chip 16, which is correspondingly face-to-face with each other in the width direction of the shielding portion 20A. In order to prevent contact between the bonding leads Wi, the sensor chip 16 and the shielding portion 20A in the pressure transmission medium PM described below, the predetermined gap is set to at least about 0.1 mm.

[0044] Regarding the relative positions of the shielding member 20, the input / output terminal group 40ai, and the sensor chip 16 of the sensor chip / terminal fixing member 14, the position of the surface of the sensor chip 16 facing the shielding portion 20A of the shielding member 20 is closer to the position of the shielding portion 20A than the position of the end face of the input / output terminal group 40ai, which protrudes from the end face of the sensor chip / terminal support member 14 parallel to the central axis of the sensor chip 16.

[0045] As described in Patent Document 1, currently, the shielding component covers the sensor chip 16 by extending over the bonding leads Wi, so that the shielding component does not interfere with the bonding leads Wi arranged around the sensor chip 16. In this configuration, as in... Figure 4C As shown in the enlarged view, the shielding portion 20A of the shielding member 20 is positioned closer to the center of the sensor chip 16 than the top Wit of the bend of the bonding lead Wi; that is, it is positioned to cover the sensor chip 16 corresponding to the inner side of the bend of the bonding lead Wi facing each other. More preferably, the end of the shielding portion 20A of the shielding member 20 in the width direction is positioned closer to the center of the sensor chip 16 and isolated from the top Wit of the bend of the bonding lead Wi, and is also closer to the connection end Wie of the bend of the bonding lead Wi.

[0046] Therefore, the shielding portion 20A is positioned closer to the surface of the sensor chip 16 than the position of the top Wit of the bend of the bonding lead Wi.

[0047] Furthermore, when the bonding leads Wi are arranged in a gate-shaped manner on the surface of the sensor chip 16, the position of the end of the shielding portion 20A can also be configured closer to the connection end that is isolated from the center of the sensor chip 16 than the top of the connection end directly above the connection end of the bonding leads Wi.

[0048] An oil-filling tube 44 is inserted into a hole formed in the fixed end 20B. The fixed end 20C is soldered to one end of the conductor pattern 22 formed on the end face of the sensor chip / terminal fixing member 14, such that it corresponds to the position of two adjacent predetermined terminals in the input / output terminal group 40ai. The fixed end 20B is soldered to the other end of the conductor pattern 22. Figure 1BAs shown, a conductor pattern 22 with a predetermined film thickness is formed, for example by plating or metallization, to simulate the arrangement of one end of the input / output terminal group 40ai formed along the circumferential direction of the sensor chip / terminal fixing member 14. This arrangement is placed between the arrangement of one end of the input / output terminal group 40ai and the inner circumferential surface 12a of the housing 12. The conductor pattern 22 is connected and conductive via a bonding lead Wib connected to any one of the input / output terminal groups 40ai, for example, a GND terminal (zero (V) terminal). The GND terminal is connected to the sensor chip 16 via the bonding lead Wia. Thus, the shielding member 20 becomes at the same potential as the signal processing electronic circuit mounted on the sensor chip 16. Therefore, by configuring the shielding member 20, which is at the same potential as the sensor chip 16, between the diaphragm 32 and the signal processing electronic circuit section of the sensor chip 16, the electric field acting on the sensor chip 16 due to the potential difference between the diaphragm 32 (which has the same potential as the primary power supply (not shown) of the unit) and the control circuit (not shown) side is cut off by the shielding member 20. Furthermore, since the potential of the shielding member 20 is the same as that of the sensor chip 16, no electric field is generated between them. Therefore, the potential difference generated between the sensor chip 16 and the diaphragm 32 does not act on the sensor chip 16, thereby preventing interference with the signal processing electronic circuitry in the sensor chip 16. Additionally, unlike Patent Documents 1 and 2, which show conductive plates disposed within the liquid-sealed chamber 13, the shielding portion 20A of the shielding member 20 is positioned closer to the surface of the sensor chip 16 than the position of the bend in the bonding lead Wi. As a result, since the diaphragm 32 can be positioned closer to the sensor chip 16 disposed in the recessed chip mounting portion 14G, the depth of the liquid-sealed chamber 13 formed in the inner periphery of the housing 12 along the central axis of the sensor chip / terminal fixing member 14 can be shallower. This reduces the amount of pressure transmission medium PM filled in the liquid-sealed chamber 13, thereby improving the temperature characteristics of the pressure sensor output. Furthermore, at least, the same effect is achieved by covering the semiconductor strain portion of the sensor chip 16 only with the shielding component 20 (shielding portion 20A).

[0049] In the example above, one end face of the sensor chip 16 protrudes beyond the end face of the sensor chip / terminal fixing member 14 from the chip mounting portion 14G toward the liquid sealing chamber 13. However, this is not a limited example; for instance, it could also be as follows: Figure 4BAs shown, the depth of the chip mounting portion 24G of the sensor chip / terminal fixing member 24 is set such that one end face of the sensor chip 16 is coplanar with the end face of the sensor chip / terminal fixing member 24. The fixing end of the shielding member 20 is connected to the conductor pattern COL formed around the chip mounting portion 24G. As a result, the depth of the liquid sealing chamber 13 formed in the inner periphery of the housing 12 along the central axis of the sensor chip / terminal fixing member 24 can be made shallower.

[0050] Alternatively, it can be like Figure 4A As shown, the depth of the chip placement portion 43G of the sensor chip / terminal fixing member 43 is set such that one end face of the sensor chip 16 is lower than the end face of the sensor chip / terminal fixing member 43, and the sensor chip 16 is entirely embedded within the chip placement portion 43G. Furthermore, Figure 4A In this configuration, each fixed end (not shown) of the shielding member 20 is connected to the conductor pattern COL surrounding the chip setting portion 43G of the sensor chip / terminal fixing member 43. That is, each fixed end of the shielding member 20 is formed on a plane common to the shielding portion 20A.

[0051] Therefore, the depth of the liquid-sealed chamber 13 formed in the inner periphery of the housing 12 along the central axis of the sensor chip / terminal fixing member 14 can be made shallower, and the shielding portion and fixing end of the shielding member 20 can be formed on a common plane, thus simplifying the structure of the shielding member 20. Furthermore, Figure 4A and Figure 4B In the middle, to and Figure 4C In the examples shown, the same constituent elements are labeled with the same symbols and are shown, omitting repeated descriptions.

[0052] exist Figure 4A , Figure 4B ,as well as Figure 4C In the example shown, the input / output terminal group 40ai is arranged at predetermined intervals along the circumferential direction around the entire periphery of the sensor chip 16, and is electrically connected to a plurality of bonding pads formed at both ends of the sensor chip 16 via bonding leads Wi.

[0053] Not limited to such examples, for example, when the input / output terminal groups are arranged only around one end of the sensor chip 16, that is, when they are arranged within a 180° range around the sensor chip 16, the input / output terminal groups can also be electrically connected to a plurality of bonding pads formed only at one end of the sensor chip 16 via each bonding lead Wi.

[0054] In such a case, as a first variation, the shielding part of the shielded component supported by the cantilever may have a fixed end at one end that is fixed to the fixing component for the sensor chip / terminal, and the other end facing each bonding pad of the sensor chip 16 is positioned at a position that does not contact each bonding pad but is as close as possible to the connection end of each bonding lead Wi that is connected to each bonding pad of the sensor chip 16.

[0055] Furthermore, as a second variation, each fixing end, which is integrally formed with the short sides of the shielding portion of the shielding member formed along the arrangement direction of each bonding pad of the sensor chip 16, orthogonal to the long side, can be fixed to the sensor chip / terminal fixing member, for example. In this case, the position of the end of the long side of the shielding portion of the shielding member facing each bonding pad of the sensor chip 16 can also be set at a position that does not contact each bonding pad but is as close as possible to the connection end of each bonding lead Wi connected to each bonding pad of the sensor chip 16.

[0056] exist Figure 1A In the example shown, the concentric, gently undulating irregularities in the cross-section of the diaphragm 32 are relatively small, but this is not a limitation; for example, it could also be as follows: Figure 2 As shown, the uneven surface around the flat portion of the diaphragm 42 facing the shielding portion 20A of the shielding member 20 extends concentrically toward the liquid seal chamber 13. That is, the uneven surface of the diaphragm 42 may protrude more toward the liquid seal chamber 13 than toward the pressure chamber 4A relative to the imaginary plane formed by the outer periphery of the diaphragm 42. Preferably, the uneven surface protrudes toward the liquid seal chamber 13 but not toward the pressure chamber 4A. The shape of the uneven surface of the diaphragm 42 is such that it does not interfere with the components inside the liquid seal chamber 13 (sensor chip, bonding leads, input / output terminal groups, shielding member, etc.) during its protrusion toward the liquid seal chamber 13.

[0057] Therefore, the volume of the pressure transmission medium PM filled in the liquid seal chamber 13 is equal to... Figure 1A The volume of the pressure transmission medium PM filling the liquid seal chamber 13 in the example shown is further reduced compared to the previous example. Furthermore, Figure 2 In the middle, to and Figure 1A In the examples shown, the same constituent elements are labeled with the same symbols and are shown, omitting repeated descriptions.

[0058] And, for example, it can also be like Figure 3AAs shown, the outer periphery of the diaphragm 52, which engages with the housing 12, is positioned closer to the end face of the sensor chip / terminal fixing member 14 within the liquid-sealed chamber 13 than the position of the flat portion of the diaphragm 52's cross-section facing the shielding portion 20A of the shielding member 20. Alternatively, for example, it can be as follows... Figure 3B As shown, the outer periphery of the diaphragm 53, which is engaged with the housing 12, is formed to be connected to the flat portion 53B via a conical surface 53F. The conical surface 53F is connected to the flat portion 53B in the cross section of the diaphragm 53, which faces the shielding portion 20A of the shielding member 20.

[0059] This allows the housing 12 to be thinner along the central axis of the sensor chip / terminal fixing member 14.

[0060] also, Figure 3A and Figure 3B In the middle, to and Figure 1A In the examples shown, the same constituent elements are labeled with the same symbols and are shown, omitting repeated descriptions.

[0061] Figure 5A and Figure 5B The main portion of another example of the sensor unit used in one example of the pressure sensor of the present invention is shown. Furthermore, Figure 5A and Figure 5B In the middle, to and Figure 1A and Figure 1B In the examples shown, the same constituent elements are labeled with the same symbols and are shown, omitting repeated descriptions.

[0062] The sensor unit that detects the pressure in the pressure chamber 4A formed between the base plate 4 and the diaphragm 32 and sends out a detection output signal is configured to include the following components as main elements: a cylindrical metal housing 12; a metal diaphragm 32 that isolates the pressure chamber 4A from the inner periphery of the housing 12; a sensor chip 16 having multiple pressure sensing elements and a signal processing electronic circuit that processes signals from the pressure sensing elements; a metal chip mounting member 18 that supports the sensor chip 16 at one end via an adhesive layer 50; an input / output terminal group 40ai (i = 1 to 8) that is electrically connected to the sensor chip 16; and a sealing glass 19 that separates the input / output terminal group 40ai and the filling oil pipe 44 (see reference). Figure 5B It is fixed between the outer peripheral surface of the chip mounting component 18 and the inner peripheral surface of the housing 12.

[0063] In the liquid-sealed chamber 13 formed between the metal diaphragm 32 and the face-to-face sensor chip 16 and sealing glass 19, a shielding member 21, serving as an electric field cutting-off component, is disposed between one end face of the sensor chip 16 and the diaphragm 32. The outer periphery of the shielding member 21 is joined to one end face of the padding member 17 described below. The shielding member 21 cuts off the electric field that is undesirable to the signal processing electronic circuitry of the sensor chip 16. The disc-shaped shielding member 21 is made of conductive metal materials such as stainless steel, copper, or aluminum. Furthermore, the outer periphery of the shielding member 21 is joined to one end face of the padding member 17, but this is not a limited example; for instance, the outer periphery of the shielding member 21 may also be supported within a recess formed at one end of the padding member 17.

[0064] like Figure 5B As shown, the shielding member 21 has a hole 21a at a position corresponding to any one of the input / output terminal groups 40ai, such as the GND terminal (the zero (V) terminal). Thus, the pressure transmission medium PM (e.g., silicone oil) filled in the liquid-sealed chamber 13 flows through the hole 21a between the inner periphery of the pad member 17 covered by the shielding member 21 and the portion formed between the diaphragm 32 and the shielding member 21, depending on the displacement of the diaphragm 32.

[0065] The shielding component 21 is grounded via a bonding lead Wib connected to any one of the input / output terminal groups 40ai, such as the GND terminal (the zero (V) terminal). The GND terminal (the zero (V) terminal) is connected to the sensor chip 16 via the bonding lead Wia. Furthermore, the shape of the shielding component 21 is not limited to a circular plate shape; for example, it can also be... Figure 1B The shape shown is either strip-shaped or elliptical.

[0066] Furthermore, in addition to the hole 21a, the shielding member 21 may also have a hole or groove or other connecting passage formed in the padding member 17 to connect the inner peripheral surface of the padding member 17 covered by the shielding member 21 and the portion formed between the diaphragm 32 and the shielding member 21.

[0067] The gasket component 17 is formed of an insulating material, such as resin, rubber, or ceramic, which has a lower coefficient of thermal expansion than the pressure transmission medium PM. This eliminates the need for the conductive plate arranged within the liquid-sealed chamber 13 and fixing the shielding component as shown in Patent Documents 1 and 2, and allows for a shallower depth of the liquid-sealed chamber 13 formed on the inner periphery of the housing 12 along the central axis of the input / output terminal group 40ai. This reduces the internal volume of the liquid-sealed chamber 13, i.e., the amount of pressure transmission medium PM contained within it, thereby improving the temperature characteristics of the pressure sensor's output.

[0068] Furthermore, if the cross-sectional shape of the internal space of the sensor device is, for example, a rectangular cross-section as shown in Figure 1 of Patent Document 3, the aforementioned padding member 17 does not need to be an annular member; for example, the padding member may also have a rectangular cylindrical cross-section.

[0069] In addition, if the shape of the gasket component is such that the gasket component does not interfere with the sensor chip 16, the bonding lead Wi, the diaphragm 32, etc. inside the liquid seal chamber 13 and can fill the internal space volume of the liquid seal chamber 13 to the maximum extent, then the shape of the gasket component can be set to any shape.

[0070] When the shielding component 21 is disposed within the liquid-sealed chamber 13, firstly, for example, after the input / output terminal group 40ai is connected to the sensor chip 16 via bonding leads Wia, the padding component 17 is then fixed within the inner periphery 12a of the housing 12 by bonding or welding, and the shielding component 21 is joined to one end face of the padding component 17, making the padding component 17 and the shielding component 21 integral. Next, the shielding component 21 is connected to the GND terminal (zero (V) terminal) via bonding leads Wib.

[0071] Figure 6A and Figure 6B The main parts of another example of a sensor unit used in one example of the pressure sensor of the present invention are shown. Furthermore, Figure 6A and Figure 6B In the middle, to and Figure 5A and Figure 5B In the examples shown, the same constituent elements are labeled with the same symbols and are shown, omitting repeated descriptions.

[0072] exist Figure 5A and Figure 5B In the example shown, shielding component 21 is connected to the GND terminal (the zero (V) terminal) via bonding lead Wib, but instead, in Figure 6A and Figure 6B In the example shown, the shielding component 31 is connected to the GND terminal (zero (V) terminal) via the terminal connection substrate 30 and the conductor pattern of the terminal connection substrate 30, and via a relay terminal 62 connected to, for example, the GND terminal (zero (V) terminal).

[0073] The sensor unit described above, which detects the pressure formed in the pressure chamber 4A between the base plate 4 and the diaphragm 32 and sends out a detection output signal, comprises the following main components: a cylindrical metal housing 12; a metal diaphragm 32 that isolates the pressure chamber 4A from the inner periphery of the housing 12; a sensor chip 16 having multiple pressure sensing elements and a signal processing electronic circuit that processes signals from the pressure sensing elements; a metal chip mounting component 18 that supports the sensor chip 16 at one end via an adhesive layer 50; an input / output terminal group 40ai (i = 1 to 8) electrically connected to the sensor chip 16; and a sealing glass 19 that separates the input / output terminal group 40ai from the oil filling tube 44 (see reference). Figure 6B It is fixed between the outer peripheral surface of the chip mounting component 18 and the inner peripheral surface of the housing 12.

[0074] In the liquid-sealed chamber 13 formed between the metal diaphragm 32 and the face-to-face sensor chip 16 and sealing glass 19, a shielding member 31, serving as an electric field cutoff component, is disposed between one end face of the sensor chip 16 and the diaphragm 32. The outer periphery of the shielding member 31 is joined to one end face of the gasket member 17. The shielding member 31 cuts off the electric field that is undesirable to the signal processing electronic circuitry of the sensor chip 16. The disc-shaped shielding member 31 is made of conductive metal materials such as stainless steel, copper, or aluminum. Figure 6B As shown, the shielding member 31 has through holes 31a and 31b at two mutually facing locations. Thus, the pressure transmission medium PM (e.g., silicone oil) filled in the liquid-sealed chamber 13 flows through the through holes 31a and 31b between the inner periphery of the gasket member 17 covered by the shielding member 31 and the portion formed between the diaphragm 32 and the shielding member 31, depending on the displacement of the diaphragm 32. Furthermore, the shape of the shielding member 31 is not limited to a circular plate shape; for example, it can also be... Figure 1B The strip or elliptical shape is shown. In such cases, the through holes described above are not required. Alternatively, instead of the through holes 31a and 31b of the shielding member 31, a connecting path can be formed in the padding member 17 to connect the inner periphery of the padding member 17 covered by the shielding member 31 with the portion formed between the diaphragm 32 and the shielding member 31.

[0075] The shielding component 31 is soldered to the lower end of the relay terminal 62. The relay terminal 62 is arranged between two adjacent terminals in the input / output terminal group 40ai and is fixed by the sealing glass 19. The relay terminal 62, the input / output terminal group 40ai (i = 1 to 8), and the filling oil tube 44 are fixed at equal intervals along the circumference of the sealing glass 19.

[0076] The upper end of the relay terminal 62 is soldered to one end of the conductor pattern on the terminal connection substrate 30. The other end of the conductor pattern on the terminal connection substrate 30 is connected to any one of the input / output terminal groups 40ai, such as the GND terminal (zero (V) terminal). The terminal connection substrate 30 has holes at predetermined intervals along the circumferential direction for the upper end of the relay terminal 62 to pass through, and a plurality of holes for the input / output terminal groups 40ai and the filling oil pipe 44 to pass through. A conductor pattern is formed on the terminal connection substrate 30 between the periphery of the hole for the upper end of the relay terminal 62 and the periphery of the hole for the GND terminal (zero (V) terminal) to pass through.

[0077] When the shielding component 31 is disposed in the liquid-sealed chamber 13, firstly, for example, after the input / output terminal group 40ai is connected to the sensor chip 16 via bonding leads Wi, the pad component 17 is then fixed in the inner periphery 12a of the housing 12 by bonding or welding, and the shielding component 31 is joined to one end face of the pad component 17. Then, the shielding component 31 and one end of the conductor pattern of the terminal connection substrate 30 are respectively soldered to both ends of the relay terminal 62.

[0078] Therefore, the potential of the shielding member 31 becomes the same as the potential of the signal processing electronic circuit mounted on the sensor chip 16 via the conductor pattern of the relay terminal 62 and the terminal connection substrate 30. Thus, by distributing the shielding member 31, whose potential is the same as that of the sensor chip 16, between the diaphragm 32 and the signal processing electronic circuit section of the sensor chip 16, the electric field acting on the sensor chip 16 caused by the potential difference between the diaphragm 32 (with the same potential as the primary power supply unit (not shown)) and the control circuit (not shown) side is cut off by the shielding member 31. Furthermore, since the potential of the shielding member 31 is the same as that of the sensor chip 16, no electric field is generated between them. Therefore, the potential difference generated between the sensor chip 16 and the diaphragm 32 does not act on the sensor chip 16, thus preventing interference with the signal processing electronic circuit in the sensor chip 16.

[0079] Furthermore, in this embodiment, similar to the examples described above, the outer periphery of the shielding member 31 is directly joined to one end face of the padding member 17 without passing through a conductive plate. Since there is no conductive plate arranged within the liquid-sealed chamber 13 and fixing the shielding member as shown in Patent Documents 1 and 2, the depth of the liquid-sealed chamber 13 formed in the inner periphery of the housing 12 along the central axis of the input / output terminal group 40ai can be shallower. This reduces the internal volume of the liquid-sealed chamber 13, i.e., the amount of pressure transmission medium PM contained within it, thereby improving the temperature characteristics of the pressure sensor output.

Claims

1. A pressure sensor, characterized in that, Equipped with a sensor unit and an electric field cutoff component, The aforementioned sensor unit includes a sensor chip that detects pressure and sends out a detection output signal, a diaphragm that separates a liquid-sealed chamber where the sensor chip is disposed from a pressure chamber facing the liquid-sealed chamber, an input / output terminal group that is electrically connected to the sensor chip via wiring material, and a sensor chip / terminal support member that has a chip mounting section for disposing of the sensor chip and supports the sensor chip and the input / output terminal group. The aforementioned electric field interruption component is disposed between one end face of the sensor chip and the diaphragm within the aforementioned liquid-sealed chamber. It has a shielding portion located directly above the sensor chip and a fixed end connected to the shielding portion and fixed to the sensor chip / terminal support component, and interrupts the electric field acting on the sensor chip. At least one end of the shielding portion of the electric field cutting-off component is disposed in a position closer to the center of the sensor chip and isolated from the top of the curved portion of the wiring material connected to the sensor chip, and closer to the connection end of the wiring material than the top of the curved portion of the wiring material.

2. A pressure sensor, characterized in that, Equipped with a sensor unit and an electric field cutoff component, The aforementioned sensor unit includes a sensor chip that detects pressure and sends out a detection output signal, a diaphragm that separates a liquid-sealed chamber where the sensor chip is disposed from a pressure chamber facing the liquid-sealed chamber, an input / output terminal group that is electrically connected to the sensor chip via wiring material, and a sensor chip / terminal support member that has a chip mounting section for disposing of the sensor chip and supports the sensor chip and the input / output terminal group. The aforementioned electric field interruption component is disposed between one end face of the sensor chip and the diaphragm within the aforementioned liquid-sealed chamber. It has a shielding portion located directly above the sensor chip and a fixed end connected to the shielding portion and fixed to the sensor chip / terminal support component, and interrupts the electric field acting on the sensor chip. The wiring material is located closer to the center of the sensor chip than the top of the curved portion of the wiring material, and is isolated from it, and is also located closer to the connection point between the wiring material and the sensor chip. The diaphragm has a portion opposite to the shielding portion of the electric field cutting-off member. The concentrically formed protrusions and depressions connected to the two ends of the portion opposite to the shielding portion are formed in the following shape: the amount of protrusion towards the liquid seal chamber side is greater than the amount of protrusion towards the pressure chamber side relative to the imaginary plane formed by the outer periphery of the diaphragm. It protrudes towards the liquid seal chamber side but not towards the pressure chamber side. During the process of protruding towards the liquid seal chamber side, it does not interfere with the sensor chip, the wiring material, the input / output terminal group and the electric field cutting-off member inside the liquid seal chamber.

3. A pressure sensor, characterized in that, Equipped with a sensor unit and an electric field cutoff component, The aforementioned sensor unit includes a sensor chip that detects pressure and sends out a detection output signal, a diaphragm that separates a liquid-sealed chamber containing the sensor chip from a pressure chamber facing the liquid-sealed chamber, an input / output terminal group electrically connected to the sensor chip, and a sensor chip / terminal support member that has a chip mounting section containing the sensor chip and supports the sensor chip and the input / output terminal group. The aforementioned electric field interruption component is disposed between one end face of the sensor chip and the diaphragm within the aforementioned liquid-sealed chamber. It has a shielding portion located directly above the sensor chip and a fixed end connected to the shielding portion and fixed to the sensor chip / terminal support component, and interrupts the electric field acting on the sensor chip. The diaphragm has a facing portion that is opposite to the shielding portion of the electric field cutting-off member. The position of the outer edge of the diaphragm is closer to the end of the sensor chip / terminal support member in the liquid-sealed chamber than the position of the portion facing the shielding portion of the electric field cutting-off member.

4. The pressure sensor according to any one of claims 1 to 3, characterized in that, The chip mounting portion is formed concavely at the end of the support member for the sensor chip / terminal.

5. The pressure sensor according to any one of claims 1 to 3, characterized in that, A conductor pattern is formed on the end face of the support member for the sensor chip / terminal, the input / output terminal group is electrically connected to the conductor pattern, and each fixed end of the electric field cutting member is fixed to the conductor pattern.

6. A pressure sensor, characterized in that, It includes a sensor unit, a pad component, and an electric field cutoff component. The aforementioned sensor unit includes a sensor chip that detects pressure and sends out a detection output signal, a diaphragm that separates the liquid-sealed chamber where the sensor chip is disposed from a pressure chamber facing the liquid-sealed chamber, and an input / output terminal group that is electrically connected to the sensor chip via wiring material. The aforementioned gasket component is configured to surround the aforementioned sensor chip within the aforementioned liquid-sealed chamber. The aforementioned electric field interruption component is disposed between one end face of the sensor chip and the diaphragm within the liquid-sealed chamber, supported by the aforementioned gasket component, and interrupts the electric field acting on the sensor chip. The aforementioned electric field interruption component is connected to any one of the aforementioned input / output terminals via the aforementioned wiring material, and the potential of the aforementioned electric field interruption component is set to be the same as the potential of any one of the input / output terminals in the aforementioned input / output terminal group. The shape of the aforementioned liner component is such that the liner component does not interfere with the aforementioned sensor chip, the aforementioned wiring material, and the aforementioned diaphragm inside the aforementioned liquid seal chamber, and can fill the internal space volume of the aforementioned liquid seal chamber to the maximum extent.

7. The pressure sensor according to claim 6, characterized in that, The electric field cutting-off component has at least one opening that allows communication between the portion of the liquid seal chamber formed between the diaphragm and the electric field cutting-off component and the portion of the inner periphery of the pad component surrounded by the electric field cutting-off component, or between the inner side of the pad component and the portion formed between the diaphragm and the electric field cutting-off component.

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