Ultrasonic fingerprint sensor chip and electronic equipment

Abstract

The embodiment of the utility model provides an ultrasonic fingerprint sensor chip and electronic equipment. The ultrasonic fingerprint sensor chip comprises a silicon substrate, and a lower electrode, a piezoelectric layer, an upper electrode, an isolation layer and an upper electrode driving signal wire which are arranged on the silicon substrate, the piezoelectric layer is located between the lower electrode and the upper electrode, the edge, close to the first end of the upper electrode driving signal wire, of the upper electrode exceeds the edge of the first end of the piezoelectric layer to form an exceeding area, the isolation layer is located between the first end of the piezoelectric layer and the upper electrode driving signal wire and located below the upper electrode, and the isolation layer at least covers the exceeding area; the edge of the first end of the upper electrode is also provided with an interconnection contact, and the interconnection contact is electrically connected with the upper electrode driving signal wire; the upper electrode driving signal wire is used for transmitting a driving signal of the upper electrode, and the driving signal is used for controlling the piezoelectric layer to emit an ultrasonic signal. By arranging the isolation layer, the stability and quality of the ultrasonic wave fingerprint sensor chip for transmitting the ultrasonic wave signal are improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of fingerprint identification, and in particular to an ultrasonic fingerprint sensor chip and an electronic device. BACKGROUND

[0002] With the development of electronic devices, it is increasingly common for electronic devices to have fingerprint identification functions. Among them, an ultrasonic fingerprint sensor constructs a fingerprint image by emitting an ultrasonic signal to the surface of a finger and receiving a return signal, thereby achieving the purpose of identifying a fingerprint. The ultrasonic fingerprint sensor has high fingerprint identification capability, applicability and integration, and has been increasingly widely applied.

[0003] Since the ultrasonic fingerprint sensor constructs a fingerprint image by emitting an ultrasonic signal and receiving a return signal, the stability and quality of the emitted ultrasonic signal are very important. How to eliminate the fluctuations of the emitted ultrasonic signal and improve the stability and quality of the emitted ultrasonic signal becomes a technical problem to be solved. CONTENT OF THE INVENTION

[0004] Therefore, embodiments of the present application provide an ultrasonic fingerprint sensor chip and an electronic device, which improve the stability and quality of the ultrasonic fingerprint sensor chip emitting an ultrasonic signal.

[0005] In a first aspect, an ultrasonic fingerprint sensor chip is provided, comprising: a silicon substrate, a lower electrode, a piezoelectric layer, an upper electrode, an isolation layer and an upper electrode driving signal trace provided on the silicon substrate; the piezoelectric layer is located between the lower electrode and the upper electrode, an edge of a first end of the upper electrode close to the upper electrode driving signal trace exceeds an edge of a first end of the piezoelectric layer to form an excess area, the isolation layer is located between the first end of the piezoelectric layer and the upper electrode driving signal trace and below the upper electrode, and the isolation layer covers at least the excess area; the edge of the first end of the upper electrode is further provided with an interconnection contact, the interconnection contact is electrically connected with the upper electrode driving signal trace; the upper electrode driving signal trace is used for transmitting a driving signal of the upper electrode, and the driving signal is used for controlling the piezoelectric layer to emit an ultrasonic signal.

[0006] In a second aspect, an electronic device is provided, comprising the ultrasonic fingerprint sensor chip provided in the first aspect of the present application.

[0007] In the embodiment of this application, the ultrasonic fingerprint sensor chip includes a silicon substrate and a lower electrode, a piezoelectric layer, an upper electrode, an isolation layer, and an upper electrode drive signal trace disposed on the silicon substrate. The piezoelectric layer is located between the lower electrode and the upper electrode. An interconnecting contact is provided on the edge of the first end of the upper electrode, and the interconnecting contact is electrically connected to the upper electrode drive signal trace. The first end of the upper electrode and the first end of the piezoelectric layer are close to the upper electrode drive signal trace. The edge of the first end of the upper electrode extends beyond the edge of the first end of the piezoelectric layer, forming an overhang region. That is, the upper electrode directly crosses from the piezoelectric layer to the isolation layer. The junction edge between the upper electrode and the piezoelectric layer is flat and uniform. The upper electrode crosses the piezoelectric layer and is then electrically connected to the upper electrode drive signal trace through the interconnecting contact. When a drive signal is applied to the upper electrode, the piezoelectric layer generates an ultrasonic signal. Because the junction edge between the upper electrode and the piezoelectric layer is flat and uniform, the piezoelectric layer generates a uniform ultrasonic signal at the junction edge of the piezoelectric layer and the upper electrode without signal fluctuation. Although the upper electrode is connected to the upper electrode drive signal trace through interconnecting contacts, there is an isolation layer below the interconnecting contacts that does not have piezoelectric properties. Therefore, it will not generate ultrasonic signals, thereby eliminating the fluctuation of ultrasonic signals and improving the stability and quality of ultrasonic signals emitted by the ultrasonic fingerprint sensor chip. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0009] Figure 1 This is an application scenario diagram of the ultrasonic fingerprint sensor chip provided in the embodiments of this application;

[0010] Figure 2A A top view of an ultrasonic fingerprint sensor chip provided for related technologies;

[0011] Figure 2B for Figure 2A Enlarged schematic diagram of the first end of the upper middle electrode and the first end of the piezoelectric layer;

[0012] Figure 2C for Figure 2A A cross-sectional view along the AA' direction;

[0013] Figure 2D for Figure 2A The image shown is a schematic diagram of the ultrasonic waves emitted by the ultrasonic fingerprint sensor chip.

[0014] Figure 3AA top view of an ultrasonic fingerprint sensor chip provided by an embodiment of the present application;

[0015] Figure 3B For Figure 3A An enlarged schematic view of a first end of the upper electrode and a first end of the piezoelectric layer;

[0016] Figure 3C For Figure 3A A sectional view along the direction of AA';

[0017] Figure 4A A top view of an ultrasonic fingerprint sensor chip provided by an embodiment of the present application;

[0018] Figure 4B For Figure 4A An enlarged schematic view of a first end of the upper electrode and a first end of the piezoelectric layer;

[0019] Figure 4C For Figure 4A A sectional view along the direction of AA';

[0020] Figure 4D For Figure 4A Another sectional view along the direction of AA';

[0021] Figure 5A A top view of an ultrasonic fingerprint sensor chip provided by an embodiment of the present application;

[0022] Figure 5B For Figure 5A An enlarged schematic view of a first end of the upper electrode and a first end of the piezoelectric layer;

[0023] Figure 5C For Figure 5A A sectional view along the direction of AA';

[0024] Figure 6 A structural diagram of an electronic device provided by an embodiment of the present application.

[0025] Explanation of reference numerals:

[0026] 11: silicon substrate; 12: piezoelectric layer;

[0027] 13: upper electrode; 14: lower electrode;

[0028] 15: upper electrode driving signal trace; 16: passivation layer;

[0029] 17: PAD; 18: interconnection contact:

[0030] 19: protective layer; 21: first region;

[0031] 22: second region; 23: exceeding region;

[0032] 31: golden finger; 41: shielding metal layer;

[0033] 42: shielding metal layer; 51: isolation layer;

[0034] 80: display screen; 100: ultrasonic fingerprint sensor chip;

[0035] 121: first end of piezoelectric layer; 131: first end of upper electrode;

[0036] 161: passivation layer window; 200: ultrasonic fingerprint sensor chip. DETAILED DESCRIPTION

[0037] In order for those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those skilled in the art should be within the scope of protection of the embodiments of the present application.

[0038] It should be noted that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like in the embodiments of the present application indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application.

[0039] The technical solutions provided by the embodiments of the present application are applied to ultrasonic fingerprint sensor chips and devices and equipment using ultrasonic fingerprint sensor chips, and the embodiments of the present application do not limit the name and type of the device and equipment. For example, the equipment using the ultrasonic fingerprint sensor chip can be called electronic equipment, terminal equipment, communication equipment, etc. For example, the electronic equipment includes but is not limited to: mobile phone, tablet computer, smart watch, smart bracelet, etc.

[0040] Exemplary, Figure 1 An application scenario diagram of the ultrasonic fingerprint sensor chip provided by the embodiments of the present application is shown, which shows the scenario of the user unlocking the mobile phone by fingerprint. As shown in Figure 1As shown, the mobile phone includes a display screen 80 and an ultrasonic fingerprint sensor chip 100 disposed below the display screen 80. When a user's finger 86 is placed in the fingerprint recognition area of ​​the display screen 80, the ultrasonic fingerprint sensor chip 100 can generate an ultrasonic signal 81 and detect the echo signal 83 of the ultrasonic fingerprint signal 81 to perform fingerprint recognition of the user.

[0041] The following is combined with Figures 2A-2C This paper describes one implementation method of an ultrasonic fingerprint sensor chip. Figure 2A A top view of an ultrasonic fingerprint sensor chip provided for related technologies. Figure 2B for Figure 2A Enlarged schematic diagram of the first end of the upper electrode and the first end of the piezoelectric layer. Figure 2C for Figure 2A A cross-sectional view along the AA' direction.

[0042] like Figure 2A and Figure 2C As shown, the ultrasonic fingerprint sensor chip 100 includes: a silicon substrate 11, a lower electrode 14, a piezoelectric layer 12, an upper electrode 13, and an upper electrode drive signal trace 15 disposed on the silicon substrate 11.

[0043] The piezoelectric layer 12 is located between the lower electrode 14 and the upper electrode 13. The edge of the upper electrode 13 near the first end of the upper electrode drive signal line 15 is located within the edge of the first end 121 of the piezoelectric layer. An interconnecting contact 18 is also provided on the edge of the first end 131 of the upper electrode, and the interconnecting contact 18 is electrically connected to the upper electrode drive signal line 15.

[0044] The upper electrode drive signal trace 15 is used to transmit the drive signal of the upper electrode 13. The drive signal is used to control the piezoelectric layer 12 to emit ultrasonic signals.

[0045] The working principle of an ultrasonic fingerprint sensor chip is as follows: it constructs a fingerprint image by emitting ultrasonic signals onto the surface of the finger and receiving the echo signals, thereby achieving fingerprint recognition. Specifically, for example... Figure 2C As shown, the ultrasonic fingerprint sensor chip includes a piezoelectric layer 12 formed of piezoelectric material. The piezoelectric layer 12 typically has two electrodes, referred to as the upper electrode 13 and the lower electrode 14. The upper electrode 13 and the lower electrode 14 are used to apply an electric field, causing the piezoelectric layer 12 to generate the inverse piezoelectric effect, converting electrical energy into mechanical oscillations and emitting ultrasonic signals. When the ultrasonic signal encounters the fingerprint on the finger surface, the ultrasonic signal is reflected back, forming an echo signal, which is received by the ultrasonic fingerprint sensor chip. The ultrasonic fingerprint sensor chip then converts the echo signal back into an electrical signal, utilizing the density difference between the skin and air on the fingerprint surface to construct a fingerprint image. This application focuses on the technical principles and related structures of ultrasonic wave transmission.

[0046] piezoelectricity or piezoelectric effect. The piezoelectric layer is formed by piezoelectric material, which has piezoelectric properties. The piezoelectric material used by the piezoelectric layer is not limited in the present application. For example, the piezoelectric material includes quartz. The piezoelectric properties refer to that some crystals will generate voltage when subjected to external pressure, and conversely, if there is voltage between the two sides of some crystals, the shape of the crystals will be slightly deformed. Specifically, when the crystals are subjected to pressure, the shape will change, and some atomic distances will become closer or farther, which will disturb the original balance and result in net electrical charge, and positive and negative charges will appear on the surface of the crystals, which is called piezoelectric effect. Conversely, when voltage is applied to both ends of the crystals, the atoms are subjected to electrical pressure, and in order to maintain the balance of the charges, the atoms vibrate back and forth, which causes the piezoelectric crystals to be slightly deformed, which is called reverse-piezoelectric effect.

[0047] In the present implementation, as shown in Figure 2A and Figure 2C , the upper electrode driving signal wire 15 is used to transmit the driving signal of the upper electrode 13, and the driving signal of the upper electrode 13 is applied to the upper electrode 13. The driving signal of the upper electrode 13 is an alternating current signal. Optionally, the driving signal of the upper electrode 13 is a pulse signal. The lower electrode 14 also needs to be applied with the driving signal of the lower electrode 14, and the generation method and transmission method of the driving signal of the lower electrode 14 are not limited in the present application. The piezoelectric layer 12 generates reverse-piezoelectric effect when the corresponding driving signals are applied to the upper electrode 13 and the lower electrode 14, thereby emitting ultrasonic signals.

[0048] As shown in Figure 2A and Figure 2B , in terms of structure, the upper electrode 13 is located on the upper layer of the piezoelectric layer 12, and the end of the upper electrode 13 close to the upper electrode driving signal wire 15 is called the first end 131 of the upper electrode, and the end of the piezoelectric layer 12 close to the upper electrode driving signal wire 15 is called the first end 121 of the piezoelectric layer. The edge of the first end 131 of the upper electrode is provided with an interconnection contact 18, which is electrically connected with the upper electrode driving signal wire 15 and used to receive the driving signal of the upper electrode 13. As shown in Figure 2BAs shown, the edge of the first end 131 of the upper electrode is located within the edge of the first end 121 of the piezoelectric layer. Thus, the interconnect contact 18 needs to cross the piezoelectric layer 12 to electrically connect with the upper electrode drive signal trace 15, forming a first region 21 and a second region 22 at the first end 121 of the piezoelectric layer. The first region 21 is the overlapping area of ​​the upper electrode 13 and the piezoelectric layer 12 when the interconnect contact 18 crosses the piezoelectric layer 12. The interconnect contact 18, or in other words, the upper electrode 13, covers the top of the first region 21; however, the upper electrode 13 does not cover the top of the second region 22. Therefore, when the upper electrode 13 and the lower electrode 14 apply corresponding drive signals, there is voltage above and below the first region 21, while there is no drive signal from the upper electrode 13 above the second region 22. According to the principle of emitting ultrasonic signals described above, the piezoelectric layer 12 will emit ultrasonic signals in the first region 21, but will not emit ultrasonic signals in the second region 22.

[0049] For example, Figure 2D for Figure 2A The diagram shows an imaging representation of the ultrasonic waves emitted by the ultrasonic fingerprint sensor chip. (Refer to...) Figure 2B and Figure 2D When the ultrasonic fingerprint sensor chip is activated and emits an ultrasonic signal, an image is obtained, and there are obvious diffraction ripples near the first region.

[0050] It is evident that, for Figures 2A-2C The ultrasonic fingerprint sensor chip shown has an uneven edge shape in the overlapping area of ​​the piezoelectric layer and the first end 121 of the upper electrode. This is because the edge of the first end 131 of the upper electrode is located within the edge of the first end 121 of the piezoelectric layer, and the edge of the first end 131 of the upper electrode has interconnecting contacts 18 for electrical connection with the upper electrode drive signal trace 15. This results in abrupt edge changes in the first region. Consequently, when the ultrasonic fingerprint sensor chip is working, the presence of the upper electrode 13 above the first region on the piezoelectric layer 12 causes diffraction patterns to form near the first region, resulting in fluctuations in the emitted ultrasonic signal and consequently, low stability and quality of the emitted ultrasonic signal.

[0051] It should be noted that the ultrasonic fingerprint sensor chip may also include other structures. This application does not limit the other structures included in the ultrasonic fingerprint sensor chip or the materials used in each structure.

[0052] The upper electrode 13 is made of metal. Optionally, the upper electrode 13 is a silver paste electrode. The silver paste electrode uses silver paste as a conductive material and is formed through processes such as printing and spraying. The silver paste is formulated from silver or its compounds, flux, binder, and diluent, etc. This application does not limit the composition ratio of the silver paste or the formation method of the silver paste electrode.

[0053] Optionally, as shown in FIG. 1, the ultrasonic fingerprint sensor chip further comprises a shielding metal layer. Optionally, the shielding metal layer is located below the piezoelectric layer 12. Figure 2C

[0054] The shielding principle is generally to surround the area or circuit to be protected by using a shielding body made of metal material to control the propagation of electric field, magnetic field and electromagnetic wave, so as to prevent the outside electromagnetic field from interfering with the internal circuit, and prevent the internal circuit from interfering with the outside. It can be understood that the ultrasonic fingerprint sensor chip is a multi-layer structure, and functional circuits for realizing different functions can be arranged in different layers. The function and structure of the functional circuit are not limited in the present application. By arranging the shielding metal layer, external interference signals such as electromagnetic waves, static electricity and electron beam interference can be shielded, so that the functional circuits in the ultrasonic fingerprint sensor chip can work normally, thereby ensuring the normal work of the ultrasonic fingerprint sensor chip. Moreover, the shielding metal layer can also play a role in heat conduction and heat dissipation to prevent the ultrasonic fingerprint sensor chip from being damaged due to high temperature.

[0055] Optionally, the shielding metal layer is the top metal layer in the ultrasonic fingerprint sensor chip.

[0056] Optionally, the silicon substrate 11 further comprises a power supply trace and a ground trace, and the shielding metal layer is connected with the power supply trace or the ground trace.

[0057] Optionally, as shown in FIG. 1, the ultrasonic fingerprint sensor chip further comprises a passivation layer 16. The passivation layer 16 is located below the first end 121 of the piezoelectric layer and the interconnection contact 18 of the upper electrode 13. A window is formed in the passivation layer 16 corresponding to the interconnection contact 18, forming a passivation layer window 161, and the interconnection contact 18 is electrically connected with the upper electrode 13 through the passivation layer window 161. Figure 2C By arranging the passivation layer 16, the electrical isolation between different metal structures in the top layer of the silicon substrate 11 is realized, and at the same time a protective film is provided for the top metal layer of the silicon substrate 11, avoiding corrosion and oxidation of the metal, preventing dust, and improving the safety, use reliability and service life of the ultrasonic fingerprint sensor chip.

[0058] Optionally, as shown in FIG. 1, the ultrasonic fingerprint sensor chip further comprises a protective layer 19. The protective layer 19 covers the upper surface of the upper electrode 13.

[0059] Figure 2C

[0060] ​​​By setting the protective layer 19, the upper electrode 13 is protected from oxidation and other problems, and the protective layer 19 can also protect the piezoelectric layer 12 to ensure its piezoelectric performance, avoid the penetration and failure of the piezoelectric layer 12 and the upper electrode 13 under high temperature, high humidity and other conditions, and improve the safety, reliability and service life of the ultrasonic fingerprint sensor chip.

[0061] Optionally, as shown in FIG. 1, the ultrasonic fingerprint sensor chip further includes a PAD 17. Optionally, the PAD 17 is electrically connected with the upper electrode driving signal wire 15. Figure 2C

[0062] The PAD represents a pad, which is used to provide a circuit connection point for the ultrasonic fingerprint sensor chip, and can realize the electrical connection between the ultrasonic fingerprint sensor chip and an external circuit structure. For example, the ultrasonic fingerprint sensor chip can be electrically connected with a gold finger 31, a flexible printed circuit (FPC), etc. through the PAD 17. The ultrasonic fingerprint sensor chip can transmit the detected fingerprint image signal to other components in the electronic device, such as a processor, through the gold finger 31 or the flexible printed circuit.

[0063] In summary, Figures 2A-2C As shown in FIG. 1, the ultrasonic fingerprint sensor chip has the problem of wave fluctuation when transmitting ultrasonic waves.

[0064] The embodiment of the present application provides an ultrasonic fingerprint sensor chip. By designing the shape of the upper electrode across the edge of the piezoelectric layer as a flat shape, and setting an isolation layer between the piezoelectric layer, the upper electrode and the upper electrode driving signal wire, the wave fluctuation of the transmitted ultrasonic signal is avoided, the stability and quality of the ultrasonic signal transmitted by the ultrasonic fingerprint sensor chip during operation are improved, and the fingerprint recognition effect of the ultrasonic fingerprint sensor chip is further improved.

[0065] The embodiment of the present application will be further described below with reference to the accompanying drawings.

[0066] It should be noted that the features in each embodiment of the present application can be combined with each other, and the same features and effects can be referred to each other.

[0067] Figure 3A A top view of the ultrasonic fingerprint sensor chip provided by the embodiment of the present application, Figure 3B A top view of the ultrasonic fingerprint sensor chip provided by the embodiment of the present application, Figure 3A An enlarged schematic view of the first end of the upper electrode and the first end of the piezoelectric layer, Figure 3C An enlarged schematic view of the first end of the upper electrode and the first end of the piezoelectric layer, Figure 3A A sectional view along the direction of AA' of the ultrasonic fingerprint sensor chip provided by the embodiment of the present application. As shown in FIG. 2, the ultrasonic fingerprint sensor chip provided by the embodiment of the present application includes: Figures 3A-3C

[0068] ​​A silicon substrate 11, a lower electrode 14, a piezoelectric layer 12, an upper electrode 13, an isolation layer 51 and an upper electrode driving signal trace 15 arranged on the silicon substrate 11.

[0069] The piezoelectric layer 12 is located between the lower electrode 14 and the upper electrode 13. An edge of the first end of the upper electrode 13 close to the first end of the upper electrode driving signal trace 15 extends beyond an edge of the first end 121 of the piezoelectric layer to form an overhanging region 23. The isolation layer 51 is located between the first end 121 of the piezoelectric layer and the upper electrode driving signal trace 15 and under the upper electrode 13, and covers at least the overhanging region 23.

[0070] The edge of the first end 131 of the upper electrode is also provided with an interconnection contact 18 which is electrically connected to the upper electrode driving signal trace 15.

[0071] The upper electrode driving signal trace 15 is used to transmit a driving signal of the upper electrode 13, and the driving signal is used to control the piezoelectric layer 12 to emit an ultrasonic signal.

[0072] The ultrasonic fingerprint sensor chip provided by the embodiment is structurally as shown in Figure 3C The piezoelectric layer 12 is located between the upper electrode 13 and the lower electrode 14. For the convenience of description, one end of the upper electrode 13 close to the upper electrode driving signal trace 15 is referred to as the first end 131 of the upper electrode, and one end of the piezoelectric layer 12 close to the upper electrode driving signal trace 15 is referred to as the first end 121 of the piezoelectric layer. One end of the upper electrode driving signal trace 15 close to the upper electrode 13 and the piezoelectric layer 12 is referred to as the first end of the upper electrode driving signal trace 15. That is, the first end 131 of the upper electrode, the first end 121 of the piezoelectric layer and the first end of the upper electrode driving signal trace 15 are close to each other. An edge of the first end 131 of the upper electrode is provided with an interconnection contact 18 which is electrically connected to the upper electrode driving signal trace 15 and used to receive a driving signal of the upper electrode 13.

[0073] With Figures 2A-2CCompared with the ultrasonic fingerprint sensor chip shown in the figure, the ultrasonic fingerprint sensor chip provided in the embodiment further comprises an isolation layer 51 located between the first end 121 of the piezoelectric layer and the upper electrode driving signal wire 15 and below the upper electrode 13. The isolation layer 51 is formed of an insulating material. Moreover, the isolation layer 51 does not have piezoelectric properties, or the piezoelectric coefficient of the isolation layer 51 is much smaller than the piezoelectric coefficient of the piezoelectric layer 12. The piezoelectric coefficient is an important indicator for evaluating the strength of piezoelectric properties of a piezoelectric material. There are various expressions or calculation methods for the piezoelectric coefficient, which are not limited in the embodiment. For example, the piezoelectric coefficient can be the piezoelectric constant d. Generally, the smaller the piezoelectric coefficient, the weaker the piezoelectric properties of the piezoelectric material, or even the piezoelectric material does not have piezoelectric properties. In the case where the piezoelectric coefficient of the isolation layer 51 is much smaller than the piezoelectric coefficient of the piezoelectric layer 12, when the upper electrode 13 and the lower electrode 14 respectively apply corresponding driving signals, even if part of the isolation layer 51 is covered by the upper electrode 13, and even if the isolation layer 51 generates a very weak ultrasonic signal, the ultrasonic signal generated by the piezoelectric layer 12 will not be affected, so the influence on the piezoelectric layer 12 can be ignored. In the case where the isolation layer 51 does not have piezoelectric properties, when the upper electrode 13 and the lower electrode 14 respectively apply corresponding driving signals, even if part of the isolation layer 51 is covered by the upper electrode 13, the isolation layer 51 will not generate an ultrasonic signal.

[0074] Optionally, the isolation layer 51 is a plastic material. The plastic material does not have piezoelectric properties, so the isolation layer 51 formed of the plastic material will not generate an ultrasonic signal to affect the ultrasonic signal emitted by the ultrasonic fingerprint sensor chip.

[0075] Optionally, the plastic material includes a polyimide (PI) material.

[0076] Optionally, the ratio of the piezoelectric coefficient of the isolation layer 51 to the piezoelectric coefficient of the piezoelectric layer 12 is less than 1 / 5.

[0077] For convenience of description, one end of the isolation layer 51 close to the piezoelectric layer 12 is referred to as the first end of the isolation layer 51, and the opposite end of the isolation layer 51 close to the upper electrode driving signal wire 15 is referred to as the second end of the isolation layer 51. The isolation layer 51 is located between the first end 121 of the piezoelectric layer and the upper electrode driving signal wire 15. Optionally, the side end surface of the first end of the isolation layer 51 is adjacent to the side end surface of the first end 121 of the piezoelectric layer (see the structure shown in the following Figure 4C or Figure 4D the structure shown in the following Figure 5C(As shown in the structure), for example, the first end of the isolation layer 51 can be extended into the bottom of the first end 121 of the piezoelectric layer. It should be noted that the planar shape of the isolation layer 51 is not limited in this embodiment.

[0078] like Figure 3A and Figure 3B As shown, the edge of the first end 131 of the upper electrode extends beyond the edge of the first end 121 of the piezoelectric layer, forming an overhang region 23. Thus, the junction edge of the first end 131 of the upper electrode and the first end 121 of the piezoelectric layer is the edge of the first end 121 of the piezoelectric layer. This junction edge is flat and uniform, ensuring that the piezoelectric layer 12 generates a uniform ultrasonic signal at the junction edge. An interconnecting contact 18 is also provided on the edge of the first end 131 of the upper electrode, which is electrically connected to the upper electrode drive signal trace 15 across the isolation layer 51. Because the isolation layer 51 has weak or no piezoelectric characteristics, it will not generate ultrasonic signals, or in other words, the weak ultrasonic signals it generates will not affect the ultrasonic signals generated by the piezoelectric layer 12. Therefore, the piezoelectric layer 12 can generate a uniform ultrasonic signal, improving the stability and quality of the ultrasonic signals emitted by the piezoelectric layer 12.

[0079] As can be seen, the ultrasonic fingerprint sensor chip provided in this embodiment includes a silicon substrate and a lower electrode, a piezoelectric layer, an upper electrode, an isolation layer, and an upper electrode drive signal trace disposed on the silicon substrate. The piezoelectric layer is located between the lower electrode and the upper electrode. A protruding interconnect contact is provided on the edge of the first end of the upper electrode, and the interconnect contact is electrically connected to the upper electrode drive signal trace. The first end of the upper electrode and the first end of the piezoelectric layer are close to the upper electrode drive signal trace. The edge of the first end of the upper electrode extends beyond the edge of the first end of the piezoelectric layer, forming an overhang region. That is, the upper electrode directly crosses from the piezoelectric layer to the isolation layer. The junction edge between the upper electrode and the piezoelectric layer is flat and uniform. The upper electrode crosses the piezoelectric layer and then is electrically connected to the upper electrode drive signal trace through the interconnect contact. When a drive signal is applied to the upper electrode, the piezoelectric layer will generate an ultrasonic signal. Because the junction edge between the upper electrode and the piezoelectric layer is flat and uniform, the piezoelectric layer generates a uniform ultrasonic signal at the junction edge of the piezoelectric layer and the upper electrode without signal fluctuation. Although the upper electrode is connected to the upper electrode drive signal trace through interconnecting contacts, there is an isolation layer below the interconnecting contacts that does not have piezoelectric properties. Therefore, it will not generate ultrasonic signals, thereby eliminating the fluctuation of ultrasonic signals and improving the stability and quality of ultrasonic signals emitted by the ultrasonic fingerprint sensor chip.

[0080] Optionally, the thickness of the isolation layer 51 is less than the thickness of the piezoelectric layer 12. Optionally, the thickness of the isolation layer 51 is less than 10 μm. See also Figure 3CBy setting the thickness of the isolation layer 51 to be less than the thickness of the piezoelectric layer 12, the upper surface of the isolation layer 51 can be lower than the upper surface of the piezoelectric layer 12, which reduces the process difficulty of the upper electrode 13 as a whole crossing the edge of the first end 121 of the piezoelectric layer, and is easy to implement.

[0081] Optionally, the thickness of the isolation layer 51 is less than the sum of the thickness of the piezoelectric layer 12 and the first thickness of the upper electrode 13, and the first thickness is the thickness of the upper electrode 13 at positions other than the overhanging region 23 and the interconnection contact 18. Optionally, the first thickness is between 10um and 40um. See Figure 3C Optionally, the thickness of the isolation layer 51 is less than the sum of the thickness of the piezoelectric layer 12 and the first thickness of the upper electrode 13, and the first thickness is the thickness of the upper electrode 13 at positions other than the overhanging region 23 and the interconnection contact 18. Optionally, the first thickness is between 10um and 40um. See

[0082] It should be noted that the ultrasonic fingerprint sensor chip can also include other structures, and the present application does not limit the materials used by the ultrasonic fingerprint sensor chip and the materials used by each structure.

[0083] Optionally, the upper electrode 13 and the lower electrode 14 are usually made of conductive materials, such as metals or conductive polymers. The conductive material is processed onto the surface of the piezoelectric material by chemical deposition, physical evaporation or other processes to form a good electrode-piezoelectric material interface and stable electrode connection, which improves the stability and quality of the piezoelectric layer 12 emitting ultrasonic signals.

[0084] Optionally, the upper electrode 13 can be a silver paste electrode.

[0085] Optionally, as shown in Figure 3C The ultrasonic fingerprint sensor chip can also include a shielding metal layer, a passivation layer (not shown), a protective layer 19 and a PAD 17. The passivation layer has a passivation layer window 161 formed at a position corresponding to the interconnection contact 18. The interconnection contact 18 is electrically connected to the upper electrode 13 through the passivation layer window. For details, please refer to the related description of the above Figures 2A-2C .

[0086] Optionally, a shielding metal layer (not shown) is further provided below the isolation layer 51.

[0087] The ultrasonic fingerprint sensor chip is a multi-layer structure, and functional circuits for implementing different functions can be arranged in different layers. The application does not limit the functions and structures of the functional circuits. By arranging the shielding metal layer below the isolation layer 51, the functional circuits below the upper electrode 13 are shielded from interference, ensuring the normal operation of the functional circuits below the upper electrode 13, and further ensuring the normal operation of the ultrasonic fingerprint sensor chip.

[0088] Optionally, the edge of the first end 121 of the piezoelectric layer is located between the two ends of the shielding metal layer arranged below the isolation layer 51.

[0089] In the present implementation, since the upper electrode 13 entirely covers the edge of the first end 121 of the piezoelectric layer, the shielding metal layer arranged below the isolation layer 51 at least covers the edge of the first end 121 of the piezoelectric layer, shields the functional circuits near the edge of the first end 121 of the piezoelectric layer in the ultrasonic fingerprint sensor chip from interference, enables the functional circuits to work normally, and further ensures the normal operation of the ultrasonic fingerprint sensor chip.

[0090] Optionally, the silicon substrate 11 further includes a power supply trace and a ground trace, and the shielding metal arranged below the isolation layer 51 is connected with the power supply trace or the ground trace.

[0091] Based on the above Figures 3A-3C embodiment, the application further provides an ultrasonic fingerprint sensor chip. In the present embodiment, an isolation layer is arranged at the edge of the first end of the piezoelectric layer.

[0092] Figure 4A A top view of the ultrasonic fingerprint sensor chip provided by the present embodiment, Figure 4B for Figure 4A the first end of the upper electrode and the first end of the piezoelectric layer, Figure 4C for Figure 4A a sectional view along the direction of AA'. As Figures 4A-4C shown, the ultrasonic fingerprint sensor chip provided by the present embodiment includes:

[0093] a silicon substrate 11, a lower electrode 14, a piezoelectric layer 12, an upper electrode 13, an isolation layer 51, and an upper electrode driving signal trace 15 arranged on the silicon substrate 11.

[0094] The piezoelectric layer 12 is located between the lower electrode 14 and the upper electrode 13, the edge of the first end of the upper electrode 13 near the upper electrode driving signal trace 15 exceeds the edge of the first end 121 of the piezoelectric layer to form an excess region 23, the isolation layer 51 is located between the first end 121 of the piezoelectric layer and the upper electrode driving signal trace 15 and below the upper electrode 13, and the isolation layer 51 at least covers the excess region 23.

[0095] The edge of the first end 131 of the upper electrode is also provided with an interconnection contact 18, which is electrically connected with the upper electrode driving signal wire 15.

[0096] The upper electrode driving signal wire 15 is used for transmitting a driving signal of the upper electrode 13, which is used for controlling the piezoelectric layer 12 to emit an ultrasonic signal.

[0097] The side end surface of the first end of the isolation layer 51 is in close connection with the side end surface of the first end 121 of the piezoelectric layer.

[0098] The ultrasonic fingerprint sensor chip provided by the embodiment is structurally as shown in Figure 4C The piezoelectric layer 12 is located between the upper electrode 13 and the lower electrode 14. For the convenience of description, the end of the upper electrode 13 close to the upper electrode driving signal wire 15 is referred to as the first end 131 of the upper electrode, and the end of the piezoelectric layer 12 close to the upper electrode driving signal wire 15 is referred to as the first end 121 of the piezoelectric layer. The isolation layer 51 is located between the first end 121 of the piezoelectric layer and the upper electrode driving signal wire 15 and below the upper electrode 13, and the side end surface of the first end of the isolation layer 51 is in close connection with the side end surface of the first end 121 of the piezoelectric layer, that is, the side end surface of the first end of the isolation layer 51 is adjacent to and next to the side end surface of the first end 121 of the piezoelectric layer.

[0099] As shown in Figure 4B The edge of the first end 131 of the upper electrode exceeds the edge of the first end 121 of the piezoelectric layer, forming an overhanging region 23 in the upper electrode 13. After the whole upper electrode 13 crosses the piezoelectric layer 12, the overhanging region 23 and the interconnection contact 18 on the upper electrode 13 cover the isolation layer 51. The joint edge of the first end 131 of the upper electrode and the first end 121 of the piezoelectric layer is the edge of the first end 121 of the piezoelectric layer, which is flat and uniform. Although the overhanging region 23 and the interconnection contact 18 on the upper electrode 13 cover the isolation layer 51, the piezoelectric property of the isolation layer 51 is weak or does not have piezoelectric property, so as to not excite ultrasonic signals or weak ultrasonic signals that do not affect the ultrasonic signals generated by the piezoelectric layer 12.

[0100] It can be seen that the ultrasonic fingerprint sensor chip provided in the embodiment comprises a silicon substrate, a lower electrode, a piezoelectric layer, an upper electrode, an isolation layer and an upper electrode driving signal trace arranged on the silicon substrate. The piezoelectric layer is located between the lower electrode and the upper electrode. The edge of the first end of the upper electrode is provided with a protruding interconnection contact, and the interconnection contact is electrically connected with the upper electrode driving signal trace. The edge of the first end of the upper electrode beyond the edge of the first end of the piezoelectric layer forms an overhanging area. The isolation layer is arranged in abutment at the edge of the first end of the piezoelectric layer, so that the upper electrode covers the isolation layer after crossing the piezoelectric layer as a whole. The joint edge of the upper electrode and the piezoelectric layer is flat and uniform, so that the piezoelectric layer generates uniform ultrasonic signals. Although the overhanging area and the interconnection contact on the upper electrode are covered on the isolation layer and are electrically connected with the upper electrode driving signal trace, the isolation layer does not have piezoelectric characteristics, so it will not excite ultrasonic signals, avoiding fluctuations in the emitted ultrasonic signals, and improving the stability and quality of the ultrasonic fingerprint sensor chip in emitting ultrasonic signals.

[0101] Optionally, the spacing between the side end surface of the first end of the isolation layer 51 and the side end surface of the first end 121 of the piezoelectric layer is less than or equal to 2um.

[0102] It can be understood that the side end surface of the first end of the isolation layer 51 is arranged in abutment with the side end surface of the first end 121 of the piezoelectric layer. In theory, there can be no gap between the side end surfaces of the two. However, in the actual production process, due to factors such as manufacturing process and manufacturing equipment, there may be a gap and a distance between the side end surface of the first end of the isolation layer 51 and the side end surface of the first end 121 of the piezoelectric layer, which needs to be controlled within a certain error range, and the smaller the better. In the embodiment, the spacing between the side end surface of the first end of the isolation layer 51 and the side end surface of the first end 121 of the piezoelectric layer is less than or equal to 2um, thereby ensuring the piezoelectric isolation effect of the isolation layer 51 between the piezoelectric layer 12 and the upper electrode 13, and ensuring the uniformity, stability and quality of the piezoelectric layer 12 in emitting ultrasonic signals.

[0103] Optionally, the isolation layer 51 is a plastic material. The plastic material does not have piezoelectric characteristics. By arranging the isolation layer 51 formed of a plastic material in abutment at the edge of the first end 121 of the piezoelectric layer, the isolation layer 51 will not generate ultrasonic signals to affect the fluctuations of the ultrasonic signals emitted by the ultrasonic fingerprint sensor chip.

[0104] Optionally, the isolation layer 51 is a PI layer formed of a PI material. The PI material does not have piezoelectric characteristics. Therefore, by arranging the PI layer in abutment at the edge of the first end 121 of the piezoelectric layer, the PI layer will not generate ultrasonic signals to affect the fluctuations of the ultrasonic signals emitted by the ultrasonic fingerprint sensor chip.

[0105] Optionally, the ratio of the piezoelectric coefficient of the isolation layer 51 to the piezoelectric coefficient of the piezoelectric layer 12 is less than 1 / 5.

[0106] In this implementation, the piezoelectric coefficient of the isolation layer 51 is much smaller than the piezoelectric coefficient of the piezoelectric layer 12, and the isolation layer 51 has weak piezoelectric characteristics or can be considered to have no piezoelectric characteristics compared to the piezoelectric layer 12, so the isolation layer 51 will not generate ultrasonic signals to cause fluctuations in the ultrasonic signals emitted by the ultrasonic fingerprint sensor chip.

[0107] Optionally, the thickness of the isolation layer 51 is less than the thickness of the piezoelectric layer 12. Optionally, the thickness of the isolation layer 51 is less than 10 um.

[0108] Optionally, the thickness of the isolation layer 51 is less than the sum of the thickness of the piezoelectric layer 12 and the first thickness of the upper electrode 13, and the first thickness is the thickness of the upper electrode 13 at positions other than the overhanging area 23 and the interconnection contact 18. Optionally, the first thickness is between 10 um and 40 um.

[0109] Optionally, as shown in Figure 4C , the ultrasonic fingerprint sensor chip further comprises a passivation layer 16. The passivation layer 16 is located below the interconnection contact 18 on the upper electrode 13. The passivation layer 16 has a window corresponding to the interconnection contact 18, forming a passivation layer window 161, and the interconnection contact 18 is electrically connected to the upper electrode 13 through the passivation layer window 161.

[0110] Optionally, as shown in Figure 4D , the passivation layer 16 in the ultrasonic fingerprint sensor chip is also located below the first end 121 of the piezoelectric layer and the isolation layer 51.

[0111] In this implementation, compared to Figures 2A-2C , the ultrasonic fingerprint sensor chip, the isolation layer 51 is attached to the upper layer of the passivation layer 16 and at the edge of the first end 121 of the piezoelectric layer. Since the isolation layer 51 has no piezoelectric characteristics, the upper electrode 13 covers the isolation layer 51 after crossing the piezoelectric layer 12 as a whole, ensuring the piezoelectric isolation effect of the isolation layer 51 between the piezoelectric layer 12 and the upper electrode 13, and ensuring the uniformity, stability and quality of the ultrasonic signals emitted by the piezoelectric layer 12.

[0112] Optionally, as shown in Figure 4D , a shielding metal layer 42 is further provided below the isolation layer 51. The normal operation of the functional circuit below the isolation layer 51 in the ultrasonic fingerprint sensor chip is ensured, and the normal operation of the ultrasonic fingerprint sensor chip is further ensured.

[0113] Optionally, as shown in Figure 4DAs shown, the ultrasonic fingerprint sensor chip further comprises a passivation layer 16 located below the first end 121 of the piezoelectric layer and the upper electrode 13. A shielding metal layer 42 is located below the passivation layer 16, or the shielding metal layer 42 is embedded in the bottom of the passivation layer 16. By arranging the shielding metal layer 42, the normal operation of the functional circuit below the isolation layer 51 in the ultrasonic fingerprint sensor chip is ensured, and thus the normal operation of the ultrasonic fingerprint sensor chip is ensured.

[0114] Optionally, the edge of the first end 121 of the piezoelectric layer is located between the two ends of the shielding metal layer 42.

[0115] It should be noted that the ultrasonic fingerprint sensor chip can further comprise other structures, and the present application does not limit the other structures included in the ultrasonic fingerprint sensor chip and the materials used by each structure.

[0116] Optionally, the ultrasonic fingerprint sensor chip can further comprise a shielding metal layer 41, a protective layer 19 and a PAD 17, which can be referred to the related description above, and will not be described here.

[0117] Based on the above Figures 3A-3C Based on the above

[0118] Figure 5A A top view of the ultrasonic fingerprint sensor chip provided by the present embodiment, Figure 5B A top view of the ultrasonic fingerprint sensor chip provided by the present embodiment, Figure 5A An enlarged schematic view of the first end of the upper electrode and the first end of the piezoelectric layer, Figure 5C An enlarged schematic view of the first end of the upper electrode and the first end of the piezoelectric layer, Figure 5A A sectional view along the direction of AA' of the ultrasonic fingerprint sensor chip provided by the present embodiment. As Figures 5A-5C As shown, the ultrasonic fingerprint sensor chip provided by the present embodiment comprises:

[0119] A silicon substrate 11, a lower electrode 14, a piezoelectric layer 12, an upper electrode 13, an isolation layer 51 and an upper electrode driving signal trace 15 arranged on the silicon substrate 11.

[0120] The piezoelectric layer 12 is located between the lower electrode 14 and the upper electrode 13, the edge of the first end of the upper electrode 13 near the upper electrode driving signal trace 15 exceeds the edge of the first end 121 of the piezoelectric layer to form an excess region 23, the isolation layer 51 is located between the first end 121 of the piezoelectric layer and the upper electrode driving signal trace 15 and below the upper electrode 13, and the isolation layer 51 covers at least the excess region 23.

[0121] The edge of the first end 131 of the upper electrode is further provided with an interconnection contact 18, and the interconnection contact 18 is electrically connected with the upper electrode driving signal trace 15.

[0122] The upper electrode drive signal trace 15 is used to transmit the drive signal of the upper electrode 13. The drive signal is used to control the piezoelectric layer 12 to emit ultrasonic signals.

[0123] The isolation layer 51 is a passivation layer 16 disposed on the silicon substrate 11, and the passivation layer 16 is located below the first end 121 of the piezoelectric layer and the upper electrode 13.

[0124] The ultrasonic fingerprint sensor chip provided in this embodiment, in terms of structure, is as follows: Figure 5C As shown, the piezoelectric layer 12 is located between the upper electrode 13 and the lower electrode 14. For ease of explanation, the end of the upper electrode 13 closest to the upper electrode drive signal trace 15 is referred to as the first end 131 of the upper electrode, and the end of the piezoelectric layer 12 closest to the upper electrode drive signal trace 15 is referred to as the first end 121 of the piezoelectric layer. The ultrasonic fingerprint sensor chip also includes a passivation layer 16, which is located below the first end 121 of the piezoelectric layer and the upper electrode 13. An isolation layer 51 is located between the first end 121 of the piezoelectric layer and the upper electrode drive signal trace 15, and is located below the upper electrode 13. Specifically, the isolation layer 51 is the passivation layer 16; or it can be understood as: the isolation layer 51 is a part of the passivation layer 16, specifically the portion of the isolation layer 51 located below the first end 121 of the piezoelectric layer and the first end 131 of the upper electrode.

[0125] like Figure 5B As shown, the edge of the first end 131 of the upper electrode extends beyond the edge of the first end 121 of the piezoelectric layer, forming an overhang region 23 in the upper electrode 13. After the upper electrode 13 completely crosses the piezoelectric layer 12, the overhang region 23 and the interconnecting contact 18 on the upper electrode 13 cover the isolation layer 51 / passivation layer 16. The junction edge of the first end 131 of the upper electrode and the first end 121 of the piezoelectric layer is the edge of the first end 121 of the piezoelectric layer. The junction edge is flat and uniform. Although the overhang region 23 and the interconnecting contact 18 on the upper electrode 13 cover the isolation layer 51 / passivation layer 16, since the piezoelectric characteristics of the isolation layer 51 / passivation layer 16 are weak or non-existent, it will not excite ultrasonic signals, or in other words, the weak ultrasonic signals excited will not affect the ultrasonic signals generated by the piezoelectric layer 12.

[0126] This embodiment is compared to Figures 2A-2C The ultrasonic fingerprint sensor chips shown share the following structural similarities: all ultrasonic fingerprint sensor chips include a passivation layer 16, which is located below the first end 121 of the piezoelectric layer and the upper electrode 13. The structural differences are: Figures 2A-2CIn the prior art, the edge of the first end 131 of the upper electrode is within the edge of the first end 121 of the piezoelectric layer, so the interconnection contact 18 arranged at the first end 131 of the upper electrode needs to first cross the piezoelectric layer 12 and then cover the passivation layer 16, resulting in a sudden change at the joint edge of the first end 131 of the upper electrode and the first end 121 of the piezoelectric layer. In the present embodiment, the edge of the first end 131 of the upper electrode is beyond the edge of the first end 121 of the piezoelectric layer to form an overhanging region 23, so the first end 131 of the upper electrode first crosses the piezoelectric layer 12 as a whole, and the interconnection contact 18 arranged at the first end 131 of the upper electrode and the overhanging region 23 directly cover the passivation layer 16 without directly covering the piezoelectric layer 12, so the joint edge of the first end 131 of the upper electrode and the first end 121 of the piezoelectric layer is smooth and even.

[0127] It can be seen that the ultrasonic fingerprint sensor chip provided by the present embodiment comprises a silicon substrate, a lower electrode, a piezoelectric layer, an upper electrode, an isolation layer and an upper electrode driving signal trace arranged on the silicon substrate, and a passivation layer. The isolation layer is the passivation layer. The piezoelectric layer is located between the lower electrode and the upper electrode. The edge of the first end of the upper electrode is provided with a protruding interconnection contact, and the interconnection contact is electrically connected with the upper electrode driving signal trace. The edge of the first end of the upper electrode is beyond the edge of the first end of the piezoelectric layer to form an overhanging region. The upper electrode covers the isolation layer / passivation layer after crossing the piezoelectric layer as a whole. The joint edge of the upper electrode and the piezoelectric layer is smooth and even, so that the piezoelectric layer generates uniform ultrasonic signals. Although the overhanging region and the interconnection contact on the upper electrode cover the isolation layer / passivation layer and are electrically connected with the upper electrode driving signal trace, the isolation layer / passivation layer does not have piezoelectric properties, so it will not excite ultrasonic signals, avoiding fluctuations in the emitted ultrasonic signals and improving the stability and quality of the ultrasonic fingerprint sensor chip in emitting ultrasonic signals.

[0128] Optionally, as shown in FIG. 5, the passivation layer 16 extends into the bottom of the first end 121 of the piezoelectric layer. Figure 5C

[0129] Optionally, as shown in FIG. 5, the passivation layer 16 extends into the bottom of the first end 121 of the piezoelectric layer. Figure 5C Optionally, as shown in FIG. 5, a shielding metal layer 42 is further arranged below the isolation layer 51 / passivation layer 16. The shielding metal layer 42 shields the functional circuit below the isolation layer 51 / passivation layer 16 in the ultrasonic fingerprint sensor chip, ensuring the normal operation of the functional circuit and thus ensuring the normal operation of the ultrasonic fingerprint sensor chip.

[0130] Optionally, the shielding metal layer 42 is embedded in the bottom of the isolation layer 51 / passivation layer 16.

[0131] Optionally, the edge of the first end 121 of the piezoelectric layer is located between the two ends of the shielding metal layer 42.

[0132] Optionally, the thickness of the isolation layer 51 / passivation layer 16 is greater than 1.5 um.

[0133] In the embodiment, the edge of the first end 131 of the upper electrode exceeds the edge of the first end 121 of the piezoelectric layer to form an excess area 23, and the upper electrode 13 covers the isolation layer 51 / passivation layer 16 after crossing the piezoelectric layer 12 as a whole. Since the driving voltage of the upper electrode 13 in operation is a high voltage with high frequency, it may damage the functional circuit in the ultrasonic fingerprint sensor chip. Therefore, by setting the thickness of the isolation layer 51 / passivation layer 16 to be greater than 1.5 um, the isolation layer 51 / passivation layer 16 has a certain thickness, thereby ensuring the normal operation of the functional circuit in the ultrasonic fingerprint sensor chip. Moreover, if a shielding metal layer 42 is further arranged below the isolation layer 51 / passivation layer 16, the electrical breakdown between the upper electrode 13 and the shielding metal layer 42 can also be avoided, thereby further ensuring the normal operation of the functional circuit in the ultrasonic fingerprint sensor chip.

[0134] It should be noted that the ultrasonic fingerprint sensor chip can also include other structures, and the application does not limit the other structures included in the ultrasonic fingerprint sensor chip and the materials used in each structure.

[0135] Optionally, the ultrasonic fingerprint sensor chip can also include a shielding metal layer 41, a protective layer 17 and a PAD 17, which can be referred to the related description above, and will not be described here.

[0136] The application also provides an electronic device. An example of the electronic device is shown in FIG. 2. Figure 6 As shown in FIG. 2, the electronic device provided in the embodiment includes the ultrasonic fingerprint sensor chip 200 provided in the above embodiment of the application. Figure 6

[0137] The electronic device of the embodiment of the application includes but is not limited to:

[0138] (1) Mobile communication device: This type of device is characterized by having mobile communication function and providing voice and data communication as the main target. This type of terminal includes: smart phone, multimedia phone, functional phone, and low-end phone, etc.

[0139] (2) Ultra-mobile personal computer device: This type of device belongs to the category of personal computers and has computing and processing functions, and generally also has the feature of mobile Internet. This type of terminal includes: PDA, MID and UMPC devices, etc., such as iPad.

[0140] ​(3) Portable entertainment device: This type of device can display and play multimedia content. This type of device includes audio and video players (e.g., iPod), hand-held game consoles, electronic books, and smart toys and portable car navigation devices.

[0141] (4) Other electronic devices with data interaction function.

[0142] To this end, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0143] Those skilled in the art will appreciate that embodiments of the present application can be devised for a method, a system, or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0144] The computer program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks. Figure One one or more functions specified in the flowchart and / or block diagram block or blocks. Figure One means for carrying out each of the functions specified in the flowchart and / or block diagram block or blocks.

[0145] Each of the embodiments described in this specification has been described taking a progressive approach, with the same or similar parts between embodiments referring to each other, and each embodiment focusing on the differences from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts refer to the part of the description of the method embodiments.

[0146] The above merely provides an example of the present application, but is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the scope of claims of the present application.

Claims

1. An ultrasonic fingerprint sensor chip, characterized in that, include: A silicon substrate, and a lower electrode, a piezoelectric layer, an upper electrode, an isolation layer, and an upper electrode drive signal trace disposed on the silicon substrate; The piezoelectric layer is located between the lower electrode and the upper electrode. The edge of the upper electrode near the first end of the upper electrode drive signal trace extends beyond the edge of the first end of the piezoelectric layer to form an extended region. The isolation layer is located between the first end of the piezoelectric layer and the upper electrode drive signal trace and is located below the upper electrode. The isolation layer at least covers the extended region. An interconnecting contact is also provided on the edge of the first end of the upper electrode, and the interconnecting contact is electrically connected to the upper electrode drive signal trace. The upper electrode drive signal trace is used to transmit the drive signal of the upper electrode, and the drive signal is used to control the piezoelectric layer to emit ultrasonic signals.

2. The ultrasonic fingerprint sensor chip according to claim 1, wherein, The side face of the first end of the isolation layer is attached to the side face of the first end of the piezoelectric layer.

3. The ultrasonic fingerprint sensor chip according to claim 1 or 2, wherein, The distance between the side face of the first end of the isolation layer and the side face of the first end of the piezoelectric layer is less than or equal to 2 μm.

4. The ultrasonic fingerprint sensor chip according to claim 3, wherein, The thickness of the insulating layer is less than the sum of the thickness of the piezoelectric layer and the first thickness of the upper electrode, where the first thickness is the thickness of the upper electrode at locations other than the overhanging area and the interconnecting contact.

5. The ultrasonic fingerprint sensor chip according to claim 4, wherein, The first thickness is between 10 μm and 40 μm.

6. The ultrasonic fingerprint sensor chip according to any one of claims 2, 4-5, wherein, A passivation layer is also disposed on the silicon substrate, and the passivation layer is located at the first end of the piezoelectric layer and below the isolation layer.

7. The ultrasonic fingerprint sensor chip according to claim 1, wherein, The isolation layer is a passivation layer disposed on the silicon substrate, and the passivation layer is located at the first end of the piezoelectric layer and below the upper electrode.

8. The ultrasonic fingerprint sensor chip according to claim 7, wherein, The passivation layer is disposed on the bottom of the first end of the piezoelectric layer near the first end of the piezoelectric layer, and the thickness of the passivation layer is greater than 1.5 μm.

9. The ultrasonic fingerprint sensor chip according to any one of claims 1-2, 4-5, and 7-8, wherein, The thickness of the isolation layer is less than the thickness of the piezoelectric layer, and the thickness of the isolation layer is less than 10 μm.

10. The ultrasonic fingerprint sensor chip according to any one of claims 1-2, 4-5, and 7-8, wherein, A shielding metal layer is also disposed on the silicon substrate, the shielding metal layer is located below the isolation layer, and the edge of the first end of the piezoelectric layer is located between the two ends of the shielding metal layer.

11. The ultrasonic fingerprint sensor chip according to claim 10, wherein, A passivation layer is also disposed on the silicon substrate, and the passivation layer is located at the first end of the piezoelectric layer and below the upper electrode; The shielding metal layer is located below the passivation layer, or the shielding metal layer is embedded at the bottom of the passivation layer.

12. The ultrasonic fingerprint sensor chip according to claim 10, wherein, The silicon substrate also includes power traces and ground traces, and the shielding metal layer is connected to the power traces or electrically connected to the ground traces.

13. The ultrasonic fingerprint sensor chip according to any one of claims 7-8 and 11, wherein, A passivation layer window is formed at the position corresponding to the interconnection contact in the passivation layer, and the interconnection contact passes through the passivation layer window to be electrically connected to the upper electrode drive signal.

14. The ultrasonic fingerprint sensor chip according to any one of claims 1-2, 4-5, 7-8, and 11-12, wherein, The ratio of the piezoelectric coefficient of the isolation layer to the piezoelectric coefficient of the piezoelectric layer is less than 1 / 5.

15. An electronic device, characterized in that, include: The ultrasonic fingerprint sensor chip as described in any one of claims 1-14.

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