Shear force sensor element array

Abstract

To solve the problem that a pressure sensor for evaluating mechanical properties of a single cell requires resolution of about 10-plus μm in the biological and life science fields, and none of existing pressure sensors can detect pressure in a microscopic region, resulting in the use of a high-precision device such as an atomic force microscope.SOLUTION: A pressure sensor element array for detecting shear force in a microscopic region is provided by forming a piezoelectric resin membrane on a surface of an ion image sensor formed on a Si substrate, and providing multiple elastic bodies for receiving external force for converting a lateral force (shear force) into a vertical force.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sensor element array that detects microscopic shearing force and normal force with cellular-level microscopic spatial resolution, and further simultaneously detects the pH of a specimen. [Background Art]

[0002] A CMOS ion image sensor (Non-Patent Document 1) can detect a change in potential on the sensor surface accompanying a change in pH or hydrogen ion concentration, and in an extended-gate CMOS type sensor, a Ta2O5 sensitive film is formed on the outermost surface. When a piezoelectric resin film is further provided on the sensitive film, physical force can be detected. The direction of the detected force is perpendicular to the sensor surface (Non-Patent Document 2).

[0003] On the other hand, in the fields of biology and life science, the mechanical properties of cells have attracted attention. Mechanical properties refer to the deformability of cells or their resistance to deformation when subjected to mechanical force, and the evaluation thereof is characterization of cell deformation in response to mechanical force over time. One example of application is specific diagnosis of cancer cells based on deformability (hardness). In addition, in drug screening, safety can be confirmed by evaluating the cycle of muscle contraction caused by cardiomyocyte pulsation after drug administration. In these cases, it is also desirable to detect force in the horizontal direction relative to the sensor surface (which may be referred to as shearing force in this specification). [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 5-26744 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-115282 [Non-Patent Literature]

[0005] [Non-Patent Document 1] You-Na Lee, and et al., "High-density 2-um-picth pH image sensor with high-speed operation up to 1933 fps," IEEE Trans. on Biomedical Circuits aand Systems, vol.13, issue2, pp. 352-363, (2019). [Non-Patent Document 2] You-Na Lee, and et al., "Super spatial resolution pressure image sensor based on bonding technique of PVDF film on two micrometer pitch COMS potentiometric sensor array," The 20th International Conference on Solid-State Sensors, Actuators and Microsystems, W3P.111, pp. 2158-2161, (2019). [Overview of the project] [Problems that the invention aims to solve]

[0006] Patent Document 1 describes a sensor capable of detecting forces in three axial directions. The peripheral portion of a flexible disc-shaped substrate is fixed to the sensor housing, and an action body is attached to the central portion. A three-dimensional XYZ coordinate system is defined with respect to the origin O within the substrate, and four sets of detectors are arranged along the X-axis. Each detector has a sandwich structure in which a piezoelectric element is sandwiched between an upper electrode and a lower electrode. When a force Fx in the X-axis direction acts on the action body due to acceleration, the disc-shaped substrate flexes, and positive or negative charges are generated at each electrode. The manner in which the charges are generated depends on the direction of the applied force, and the amount of charge generated depends on the magnitude of the applied force. Based on this charge generation pattern, the axial components of the applied force can be detected.

[0007] In order to realize a sensor structure that can detect shear force in a minute area using the configuration shown in Patent Document 1, supporting the flexible substrate becomes a challenge. To achieve micron-level spatial resolution, it is necessary to use a semiconductor planar process, and a structure in which a piezoelectric element is sandwiched between electrodes from above and below results in a complex manufacturing process.

[0008] Patent Document 2 discloses a tactile sensor comprising a first substrate having a plurality of first electrodes, a second substrate having a plurality of second electrodes corresponding to each of the plurality of first electrodes, and a dielectric inserted between the first substrate and the second substrate, wherein the second electrode corresponding to one of the plurality of first electrodes is arranged away in one direction, and the second electrode corresponding to another first electrode adjacent to one of the plurality of first electrodes is arranged away in the other direction. The configuration detects normal force and shear force from changes in capacitance between electrodes.

[0009] Even in the structure shown in Patent Document 2, assuming the use of a semiconductor planar process, the means for supporting the dielectric layer inserted between the first and second substrates remains a challenge. It is difficult to provide the same function on both the front and back surfaces using a semiconductor planar process.

[0010] Patent documents 1 and 2 describe forming stress detection elements using flexible materials or dielectric materials as substrates. It is difficult to improve spatial resolution for detecting mechanical forces without using a semiconductor planar process suitable for microfabrication.

[0011] Pressure sensors used to evaluate the mechanical properties of minute areas, such as single cells, require a resolution of around 10-15 micrometers. Current pressure sensors cannot detect pressure in such minute areas, and high-precision instruments such as atomic force microscopes (AFMs) are used. While AFMs can detect forces over a wide range of approximately 10 pN to 10 μN, they have limitations in measurement throughput. [Means for solving the problem]

[0012] In view of the above circumstances, the inventors of the present invention have realized a sensor element array that can detect shear force in a minute region by forming a piezoelectric resin film on the surface of a CMOS-type ion image sensor formed on a Si substrate, and further providing a plurality of elastic bodies to receive external forces that convert lateral forces (shear forces) into vertical forces.

[0013] When a shear force is applied to the side of an elastic body as shown in Figure 1, shear deformation occurs. If the side shape of the elastic body is rectangular, it will deform into a parallelogram. When a shear force is applied to the left side of the elastic body, tensile stress acts along the diagonal that rises to the right, and compressive stress acts along the diagonal that falls to the left.

[0014] As described above, if the bottom surface of an elastic body is in close contact with another layer while shear deformation is occurring, the elasticity of the elastic body causes the layer to experience tensile stress at the starting point where the shear force is applied and compressive stress at the ending point. If the lower layer contains a piezoelectric resin film, the piezoelectric resin film experiences tensile stress at the starting point of the elastic body and compressive stress at the ending point. By detecting the potential change at each part of the piezoelectric resin film, the shear force applied to the elastic body can be determined.

[0015] Here, we consider the shape of the elastic body. Since a semiconductor planar process is used, the height of the elastic body is about a few μm, and 1 μm to 10 μm is appropriate, but a greater height is preferable. The shape of the elastic body as viewed from the top or bottom surface is preferably in the range of 1 μm × 1 μm to 10 μm × 10 μm, but a smaller shape of the elastic body is advantageous due to the large degree of shear deformation.

[0016] The amount of charge Qp generated when a force F is applied perpendicularly to a piezoelectric film is the piezoelectric constant d of the piezoelectric thin film. 33 It can be expressed using the following equation. Qp=d 33 ×F (1) Next, the sensitive membrane capacitance C per potential detection unit. SENS The theoretical sensitivity of the output voltage Vout to a force perpendicular to it can be calculated using the following equation. Vout = Qp / C SENS (2) Sensitive film capacitance C SENS is 0.71 fF, and when the piezoelectric constant is set to 18 pC / N as a standard value for polyvinylidene fluoride materials, the theoretical sensitivity of the output voltage is 25.3 mV / μN. According to Non-Patent Document 1, the noise level of the potential detection unit is approximately 3 mV, so a force of about 0.1 μN can be detected.

[0017] When a force is applied to an elastic body from the horizontal direction, the force in the vertical direction is determined by Poisson's ratio. When the elastic body is epoxy resin, the Poisson's ratio is around 0.3, and a force approximately 1 / 3 that of the horizontal force is applied, so the horizontal shear force can be detected as a vertical force.

[0018] A first aspect of the present invention is a shear force sensor element array, comprising: a sensing unit that changes the depth of a potential well according to a surface potential on a Si substrate; an interlayer insulating film formed on the sensing unit; a metal electrode formed on the interlayer insulating film, the metal electrode being electrically connected to the sensing unit via a metal through-hole provided in the interlayer insulation; the array has potential detection units, and the potential detection units are formed into an array; a first sensitive film made of a sensitive film (Ta₂O₅, Si₃N₄, or other thin films that adsorb hydrogen ions) is formed directly above the first metal electrode of the sensing units constituting the array; a second sensitive film made of a resin thin film having piezoelectricity is formed directly above the first sensitive film; a metal film (waterproof film) is formed directly above the second sensitive film; a plurality of elastic bodies for receiving external force are formed on the metal film; and at least two or more potential detection units are arranged directly below each elastic body.

[0019] A second aspect of the present invention is characterized in that, in the first aspect, the elastic bodies are arranged spaced apart from each other, the second sensitive film and the metal film located in gaps between the elastic bodies are removed, and the first sensitive film is exposed.

[0020] According to a third aspect of the present invention, in the first or second aspect, the present invention includes at least four elastic bodies, at least two of the elastic bodies are arranged on a first straight line, and at least two of the elastic bodies are arranged on a second straight line in a direction orthogonal to the first straight line. [Effect of the Invention]

[0021] According to the present invention, shearing force can be imaged with a spatial resolution on the μm level, and cell hardness, pulsation of cardiomyocytes, and the like, which attract attention in the fields of biology and life science, can be directly observed. Furthermore, since the pH image sensor is used as a potential detector array, chemical properties such as pH can be detected simultaneously together with the mechanical properties of cells in a culture solution. [Brief Description of the Drawings]

[0022] [Figure 1] FIG. 1 is a schematic cross-sectional view of a shear force sensor element array shown in the first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of a shear force sensor element array shown in the second embodiment. [Figure 3] FIG. 3 is a schematic perspective view showing an arrangement example of shear force detection units of a shear force sensor element array shown in the third embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a configuration of a potential detection unit according to the present embodiment. [Figure 5] FIG. 5 is a potential distribution diagram for explaining the operation of the potential detection unit according to the present embodiment. [Mode for Carrying Out the Invention]

[0023] In the shear force sensor element array according to the present invention, the potential detection unit and the piezoelectric resin film are separately manufactured, and the elastic body is formed after the two are bonded together. This is for performing polarization treatment on the piezoelectric resin film. In order to detect potentials respectively on opposite sides of the bottom surface of the elastic body, at least two potential detectors are required below each elastic body. Since the dimensions of the elastic body to which a shear force is applied are set to about several μm, the element spacing of the potential detectors is desirably about 1 to 2 μm.

[0024] (First Embodiment) Figure 1 shows a schematic cross-sectional view of the shear force sensor element array 100 according to this embodiment. Note that parts unnecessary for the explanation of the first embodiment have been omitted from the schematic cross-sectional view in Figure 1. The shear force sensor element array 100 consists of a potential detector array 60 consisting of a plurality of CMOS extended gate type potential detection units 1 and a shear force detection unit 40. The potential detection unit 1 is equipped with interlayer insulating films 30, 33, a metal electrode 35 directly above the interlayer insulating films 30, 33, and a hydrogen ion sensitive film 36 is formed in a shape that covers the metal electrode 35. The metal electrode 35 is electrically connected to the sensing area defining electrode 13 of the potential detection unit 1 via metal through holes 31, 34 and metal connection parts 32 in the interlayer insulating films 30, 33.

[0025] Next, the shear force detection unit 40 will be described. The shear force detection unit 40 is formed on the potential detector array 60 and consists of a piezoelectric resin film 42, a metal thin film 41, and an elastic body 43. The piezoelectric resin film 42 is made of polyvinylidene fluoride (PVDF) resin. PVDF is one of the thermoplastic fluoropolymers with high resistance and high purity. PVDF is a ferroelectric polymer and exhibits piezoelectric and pyroelectric properties, making it suitable for use in pressure sensors. Alternatively, a resin made of a copolymer of vinylidene fluoride and trifluoroethylene (VDF-TrFE) or a copolymer of vinylidene fluoride and tetrafluoroethylene (VDF-TeFE) may also be used.

[0026] Since the evaluation of the mechanical properties of cells is performed in an aqueous solution such as a culture medium, it is desirable to form a thin metal film 41 on the piezoelectric resin film 42 for waterproofing. In this embodiment, the Au film was formed by sputtering.

[0027] Since the elastic body 43 needs to be formed selectively in a fine region, a material that can be formed using a semiconductor planar process is desirable. In this embodiment, a thick-film resist SU-8 was used. SU-8 is a negative-type photoresist based on the epoxy resin EPON SU-8 and can be applied by spin coating. It has high viscosity, allowing for the formation of an elastic body 43 with a high aspect ratio. SU-8 is biocompatible and suitable for cell evaluation.

[0028] The dimensions of the shear force detection unit 40 were defined as follows: thickness of piezoelectric resin film 1 μm, thickness of Au thin film 200 nm, height of elastic body 43 5 μm, and elastic body pattern area 8 μm × 8 μm.

[0029] As part of the polarization process, an indium tin oxide (ITO) electrode and a PVDF film are laminated onto a polyethylene terephthalate (PET) film as a base material, and polarization is performed by applying a high voltage of approximately 10 kV. After the polarization process, the PVDF film is peeled off from the PET film by dissolving the ITO electrode.

[0030] As a transfer step, the peeled PVDF film is attached to the potential detector array 60. The transfer step is conveniently carried out in a liquid such as pure water, and it is desirable that the surfaces of the potential detector array 60 and the PVDF film be hydrophilized using O2 plasma.

[0031] After the transfer process and the Au film formation process, the elastic body 43 formation process is carried out. Thick film photoresist SU-8 is applied by spin coating at a rotation speed of 3000 rpm. It is desirable to perform heat treatment at about 100°C and hydrophobic surface treatment (e.g., HMDS treatment) as pretreatment before coating. After coating, pre-bake is performed at 95°C for 2 minutes. The elastic body 43 is formed by processing SU-8 with photolithography. Lithography is performed with i-line exposure, and after exposure, heat treatment is applied at 95°C for 1 minute. After that, the uncrosslinked portions that were not irradiated with the i-line are dissolved with a developer solution specifically for SU-8, and the surface is rinsed with isopropyl alcohol.

[0032] In the shear force sensor element array 1 fabricated by the above process, tensile stress is applied to the piezoelectric resin film 42 at the starting point of the shear force applied to the elastic body 43, and compressive stress is applied to the piezoelectric resin film 42 at the ending point of the shear force. Each piezoelectric resin film 42 generates a potential corresponding to the force it receives, and the generated potential change is transmitted via the hydrogen ion sensitive film 36 of the potential detection unit 1 to the sensing area 6 of the potential detection unit 1, which is located directly below the starting and ending points, respectively. In the case of a PVDF film, since the piezoelectric coefficient is positive, the detected potential changes in the negative direction at the starting point and in the positive direction at the ending point.

[0033] Regarding the detection results mentioned above, if the potential changes at the starting point and the ending point are in the same direction, it can be determined that a vertical force is mainly being applied. If the potential changes at the starting point and the ending point are in the same direction but the detected amounts of potential change are different, it means that an axial misalignment from the vertical is occurring. In this case, by placing the potential detection units 1 diagonally at the four corners of the bottom surface of the elastic body 43, the angle of axial misalignment from the vertical can be determined.

[0034] (Second embodiment) Figure 2 shows a schematic cross-sectional view of the shear force sensor element array 100 according to this embodiment. Note that parts unnecessary for the explanation of the second embodiment have been omitted from the schematic cross-sectional view in Figure 2. By modifying the first embodiment, a second embodiment equipped with a pH detection unit 50 is obtained. By removing the metal film and piezoelectric thin film 42 in the parts where the elastic body 43 is not formed in the first embodiment, the hydrogen ion sensitive film 36 that determines the pH is exposed. As a step in removing the metal film 41, it is desirable to use an iodine-based etching solution such as an I2+KI mixture that allows selective etching by lithography for the removal of the Au film. Alternatively, patterning is also possible using a lift-off method with photoresist, and the area to be waterproofed with a metal film may be determined in advance.

[0035] Next, as a step to remove the PVDF film, the PVDF film can be processed using a dimethylacetamide (DMA) solution as an etching solution in a wet process, or by reactive ion etching with O2 plasma in a dry process. In the second embodiment fabricated in this way, simultaneous detection of shear force and pH becomes possible.

[0036] The shear force sensor element array 100 manufactured by the above process can detect shear force in the same manner as in the first embodiment. In addition, it is equipped with a pH detection unit 50, which can detect pH.

[0037] Cancer cells are known to have different deformability and pH levels near them compared to normal cells. By using the shear force sensor element array according to the second embodiment, the deformability of cancer cells can be identified by the shear force sensor unit, and the pH change near the cancer cells can also be identified, thereby improving the accuracy of cancer cell diagnosis.

[0038] (Third embodiment) The shear force sensor element array 100 according to this embodiment can evaluate muscle contraction of cardiomyocytes and the migration of prokaryotic cells. Here, the potential detector array according to Non-Patent Literature 1 has a frame rate of approximately 2000 fps and a time resolution of approximately 0.5 msec. If multiple shear force detection units 40 are arranged in a straight line and the spacing between the shear force detection units 40 is 0.1 mm, then movement speeds of up to 0.2 m / sec (20 cm per second) can be detected. This is a sufficient speed for evaluating cell movement. In this embodiment, at least two or more shear force detection units 40 are arranged on two orthogonal lines on the x and y axes, so that the direction and speed of movement on the x and y plane can be detected. Note that even if the first and second lines do not satisfy the orthogonal relationship, the direction and speed of movement can still be detected, but the detection accuracy will decrease.

[0039] (Configuration and operation of the potential detection unit) Figure 5 shows the fundamental configuration of the CMOS extended gate type potential detection unit 1 that constitutes the shear force sensor element array 100 of this embodiment. The potential detection unit 1 is configured on a silicon substrate 2, with the sensing (Sen) region 6, the first floating diffusion (FD1) region 7, the charge transfer (TG) region 10, the second floating diffusion (FD2) region 8, the charge transfer control (AG) region 11, the charge storage (FD) region 9, the reset (RG) region 12, and the second charge discharge (D2) region 5, in that order from the first charge discharge (D1) region 4 in the direction of charge transfer.

[0040] The division of each region is defined by the difference in the conduction type of the silicon semiconductor on the surface of the silicon substrate 2. When electrons are used as the charge, the first charge discharge (D1) region 4, the first floating diffusion (FD1) region 7, the second floating diffusion (FD2) region 8, the charge accumulation (FD) region 9, and the second charge discharge (D2) region 5 are n+ type regions, while the sensing (Sen) region 6, the charge transfer (TG) region 10, the charge transfer control (AG) region 11, and the reset (RG) region 12 are p type regions.

[0041] A silicon oxide insulating film 3 is laminated on the surface of the silicon substrate 2. A sensing region defining electrode 13 is formed on the sensing (Sen) region 6. Furthermore, a silicon oxide layer 33 and a metal electrode 35 are laminated, and a tantalum pentoxide film is laminated on the surface of the metal electrode 35 as a first sensitive film 37. Potential changes on the surface of the first sensitive film 37 are transmitted to the sensing region defining electrode 13 via metal through-holes 31, 34 and metal connection parts 32 embedded in the silicon oxide layers 30, 33. A charge transfer electrode 14 is formed on the charge transfer (TG) region 10 via the silicon oxide insulating film 3, a charge transfer control electrode 15 is formed on the charge transfer control (AG) region 11 via the silicon oxide insulating film 3, and a reset electrode 16 is formed on the reset (RG) region 12 via the silicon oxide insulating film 3.

[0042] The first floating diffusion (FD1) region 7 is positioned in close proximity to the sensing (Sen) region 6 and accumulates a charge amount that reflects the potential of the sensing (Sen) region 6. The potential of the charge transfer (TG) region 10 is appropriately set to a sufficiently low voltage or sufficiently high voltage, such as the ground potential (GND) or the power supply voltage (VDD), and the charge transfer (TG) region 10 performs charge transfer between the first floating diffusion (FD1) region 7 and the second floating diffusion (FD2) region 8.

[0043] The charge transfer control (AG) region 11 is positioned in close proximity between the second floating diffusion (FD2) region 8 and the charge storage (FD) region 9, and a predetermined potential, either ground potential or between the power supply voltage and the potential of the sensing (Sen) region 6, is applied to it. The charge transfer control (AG) region 11 controls the amount of charge transferred from the second floating diffusion (FD2) region 8 to the charge storage (FD) region 9.

[0044] The reset (RG) region 12 is located in close proximity between the charge storage (FD) region 9 and the second charge discharge (D2) region 5, and is to which the ground potential or power supply voltage is applied. The reset (RG) region 12 controls the charge transfer from the charge storage (FD) region 9 to the second charge discharge (D2) region 5.

[0045] The operation of the potential detection unit 1 will be explained with reference to Figure 5. The operation of the potential detection unit 1 consists of four steps, as shown in Figures 5A to 5D. The potential height is indicated by the arrows, with the lower arrows indicating a higher potential. Here, we assume that the charge is an electron. In the following explanation, we will use electrons, which are negatively charged, as the charge.

[0046] The first charge discharge (D1) region 4 and the second charge discharge (D2) region 5 are subjected to a sufficiently high voltage throughout the entire step, such as the power supply voltage, to constantly discharge charge.

[0047] Figure 5A shows the initial state. When the potential of the reset (RG) region 12 is set to the power supply voltage, the potentials of the second charge discharge (D2) region 5 and the charge storage (FD) region 9 become equal, and the charge in the charge storage (FD) region 9 is discharged. However, an unspecified amount of charge remains in the first floating diffusion (FD1) region 7 and the second floating diffusion (FD2) region 8. At the end of this step, the potential of the reset (RG) region 12 must be set to the ground potential, and charge movement between the charge storage (FD) region 9 and the second charge discharge (D2) region 5 must be blocked.

[0048] In Figure 5B, charge is injected into the second floating diffusion (FD2) region 8. The potentials of the charge transfer (TG) region 10 and the charge transfer control (AG) region 11 are temporarily set to ground potential, and charge is injected from the charge injection circuit 20. The minimum potential of the charge held in the second floating diffusion (FD2) region 8 is equal to ground potential. At the end of this step, charge injection from the charge injection circuit 20 is terminated.

[0049] In Figure 5C, the potential of the charge transfer (TG) region 10 is set as the power supply voltage, and a portion of the charge in the second floating diffusion (FD2) region 8 is transferred to the first charge discharge (D1) region 4 via the first floating diffusion (FD1) region 7. The minimum potential of the charge remaining in the second floating diffusion (FD2) region 8 is determined by the potential of the sensing (Sen) region 6.

[0050] In Figure 5D, the potential of the charge transfer (TG) region 10 is set to the ground potential, blocking the movement of charge between the first floating diffusion (FD1) region 7 and the second floating diffusion (FD2) region 8. In this step, the lowest potential of the charge held in the first floating diffusion (FD1) region 7 is the potential detected by the sensing (Sen) region 6, and the lowest potential of the charge held in the second floating diffusion (FD2) region 8 is held at the potential of the charge transfer control (AG) region 11. At this time, by making the potential of the charge transfer control (AG) region 11 higher than the potential of the sensing (Sen) region 6, an amount of charge corresponding to the potential difference is transferred to the charge storage (FD) region 9.

[0051] Since the amount of charge accumulated in the charge storage (FD) region 9 reflects the potential height in the sensing (Sen) region 6, the potential can be measured using a buffer circuit 21 or similar device with high input impedance.

[0052] The present invention is not limited in any way to the descriptions of embodiments and examples of the invention described above. Various modifications that do not depart from the spirit of the claims and that are easily conceivable by a person skilled in the art are also included in this invention. [Explanation of Symbols]

[0053] 1. 1A~1F Potential Detection Unit 2. Silicon substrate 3. Insulating film (silicon oxide film) 4. First charge discharge (D1) region 5. Second charge discharge (D2) region 6. Sensing (Sen) area 7. First floating-diffusion (FD1) region 8. Second floating-diffusion (FD2) region 9 Charge accumulation (FD) region 10 Charge Transfer (TG) Region 11 Charge Transfer Control (AG) Region 12 Reset (RG) area 13 Sensing area defining electrode 14 Charge transfer electrodes 15 Charge transfer control electrodes 16 Reset electrode 20 Charge injection circuit 21 Output voltage detection circuit (buffer circuit) 30, 33 Interlayer insulating film (silicon oxide film) 31, 34 Metal through hole 32 Metal connection part 35 Metal electrode 36 Hydrogen ion-sensitive film 40, 40A, 40B Shear force detection unit 41 Metal membrane (for waterproofing) 42 Piezoelectric resin film 43 Elastic body 50 pH detection unit 60 Potential detector array 100 Shear force sensor element array 101 pH and shear force sensor element array

Claims

1. The system comprises a sensing unit on a Si substrate that changes the depth of a potential well according to the surface potential, and a potential detection unit in which an interlayer insulating film is formed on the sensing unit, a metal electrode is formed on the interlayer insulating film, and the metal electrode is electrically connected to the sensing unit via a metal through-hole provided within the interlayer insulating film, and the potential detection units are arranged in an array. A sensitive film (Ta) is placed directly above the metal electrode of the potential detection unit that constitutes the array. 2 O 5 Si 3 N 4 A first sensitive film is formed, consisting of a thin film that adsorbs other hydrogen ions, and a second sensitive film is formed directly above the first sensitive film, consisting of a piezoelectric resin film. A shear force sensor element array characterized in that a metal film (waterproof film) is formed directly above the second sensitive film, a plurality of elastic bodies for receiving external forces are formed as rectangular parallelepipeds on the metal film, and at least two or more potential detection units are arranged directly below the elastic bodies.

2. The shear force sensor element array according to Claim 1, characterized in that the elastic body has a shape of 1 μm × 1 μm to 10 μm × 10 μm when viewed from the top or bottom surface, and a height of 1 μm to 10 μm.

3. The shear force sensor element array according to claim 1 or 2, characterized in that at least four elastic bodies are arranged on the surface of the shear force sensor element array, at least two of the elastic bodies are arranged on a first straight line on the surface of the shear force sensor element array, and at least two of the elastic bodies are arranged on a second straight line perpendicular to the first straight line.

4. The shear force sensor element array according to claim 3, characterized in that the elastic bodies are spaced apart, the second sensitive film and the metal film located in the gaps of the elastic bodies are removed, and the first sensitive film is exposed, thereby enabling pH detection.

Images