Fingerprint recognition module and manufacturing method thereof and electronic device

Abstract

A fingerprint recognition module and its manufacturing method and electronic device. The fingerprint recognition module includes a substrate, a piezoelectric material layer, an auxiliary structure and a plurality of first drive electrodes; the piezoelectric material layer is located on the substrate, the auxiliary structure is at least partially located on the substrate, and the plurality of first drive electrodes are located on the side of the piezoelectric material and the auxiliary structure away from the substrate; each first drive electrode extends along a first direction and exceeds the first edge of the piezoelectric material layer in the first direction, the plurality of first drive electrodes are arranged at intervals along a second direction, the auxiliary structure is arranged in contact with at least the first edge, and the auxiliary structure includes a slope portion, and the thickness of the slope portion in a direction perpendicular to the functional substrate gradually decreases from the first edge to the direction away from the center of the piezoelectric material layer. The fingerprint recognition module can avoid problems such as broken wires and residual conductive materials in the process of forming a plurality of first drive electrodes on the piezoelectric material layer, thereby improving the yield of the product.

Description

[0001] This application claims the priority of Chinese Patent Application No. 201910082585.9 filed on January 28, 2019 and the priority of PCT Application No. PCT / CN2019 / 105749 filed on September 12, 2019. The contents disclosed in the above-mentioned Chinese patent application and the contents disclosed in the above-mentioned PCT application are hereby cited in their entirety as part of this application. Technical Field

[0002] Embodiments of the present disclosure relate to a fingerprint recognition module, a manufacturing method thereof, and an electronic device. Background Art

[0003] With the continuous development of science and technology, fingerprint recognition technology has gradually been applied to people's daily life. Fingerprint recognition technology can achieve the function of identity recognition by comparing the detailed feature points of different fingerprints. Generally, fingerprint recognition technology can be divided into optical fingerprint recognition technology, silicon chip fingerprint recognition technology and ultrasonic fingerprint recognition technology.

[0004] At present, ultrasonic fingerprint recognition technology is a popular research direction for major manufacturers. The ultrasonic fingerprint recognition structure is mainly a three-layer structure, including a first driving electrode, a receiving electrode, and a piezoelectric layer located between the two. When a driving voltage is applied to the first driving electrode and the receiving electrode, the piezoelectric layer is excited by the voltage to produce an inverse piezoelectric effect and emit a first ultrasonic wave outward. After the first ultrasonic wave contacts the finger, it is reflected back by the finger as a second ultrasonic wave. Since the fingerprint includes valleys and ridges, the vibration intensity of the second ultrasonic wave reflected back to the piezoelectric layer by the fingerprint varies. At this time, a fixed voltage is applied to the first driving electrode, and the piezoelectric layer can convert the second ultrasonic wave into a voltage signal. The voltage signal is transmitted to the fingerprint recognition module through the receiving electrode, and the position of the valley and ridge in the fingerprint is determined based on the voltage signal. Summary of the invention

[0005] The disclosed embodiment provides a fingerprint recognition module, a manufacturing method thereof and an electronic device. The fingerprint recognition module includes a substrate, a piezoelectric material layer, an auxiliary structure and a plurality of first drive electrodes; the piezoelectric material layer is located on the substrate, the auxiliary structure is at least partially located on the substrate, and the plurality of first drive electrodes are located on the side of the piezoelectric material and the auxiliary structure away from the substrate; each first drive electrode extends along the first direction and exceeds the first edge of the piezoelectric material layer in the first direction, the plurality of first drive electrodes are arranged at intervals along the second direction, the auxiliary structure is arranged in contact with at least the first edge, the auxiliary structure includes a slope, and the thickness of the slope in the direction perpendicular to the functional substrate gradually decreases from the first edge to the direction away from the center of the piezoelectric material layer, and the second direction intersects with the first direction. In the fingerprint recognition module, since the auxiliary structure is arranged in contact with the first edge of the piezoelectric material layer and the auxiliary structure includes a slope, problems such as disconnection and residual conductive material can be avoided in the process of forming a plurality of first drive electrodes on the piezoelectric material layer, thereby improving the yield of the product.

[0006] At least one embodiment of the present disclosure provides a fingerprint recognition module, which includes: a functional substrate; a piezoelectric material layer located on the functional substrate; an auxiliary structure located at least partially on the functional substrate; and a plurality of first drive electrodes located on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate, each of the first drive electrodes extending along a first direction and exceeding a first edge of the piezoelectric material layer in the first direction, the plurality of first drive electrodes being arranged at intervals along a second direction, the auxiliary structure being arranged in contact with at least the first edge, the auxiliary structure including a slope portion, the thickness of the slope portion in a direction perpendicular to the functional substrate gradually decreasing in a direction from the first edge to a direction away from the center of the piezoelectric material layer, and the second direction intersecting with the first direction.

[0007] For example, in a fingerprint recognition module provided in an embodiment of the present disclosure, the slope angle of the slope portion is less than 60 degrees.

[0008] For example, in a fingerprint recognition module provided in one embodiment of the present disclosure, the auxiliary structure includes: a main body portion, which is located on the functional substrate and is arranged in the same layer as the piezoelectric material layer; and an overlapping portion, which is connected to the main body portion and is located on a side of the first edge of the piezoelectric material layer away from the functional substrate.

[0009] For example, in the fingerprint recognition module provided in an embodiment of the present disclosure, the size of the overlapping portion in the first direction is greater than 200 micrometers.

[0010] For example, in the fingerprint recognition module provided in an embodiment of the present disclosure, the material of the auxiliary structure includes curing glue.

[0011] For example, in the fingerprint recognition module provided in an embodiment of the present disclosure, the material of the auxiliary structure includes optical curing glue.

[0012] For example, in a fingerprint recognition module provided in an embodiment of the present disclosure, the material of the piezoelectric material layer includes polyvinylidene fluoride.

[0013] For example, in the fingerprint recognition module provided in an embodiment of the present disclosure, the auxiliary structure is arranged along the edge of the piezoelectric material, and the auxiliary structure is also arranged in contact with the second edge of the piezoelectric material layer in the second direction.

[0014] For example, in the fingerprint recognition module provided in an embodiment of the present disclosure, each of the first driving electrodes includes a metal layer and a transparent metal oxide layer stacked in sequence along a direction perpendicular to the functional substrate.

[0015] For example, a fingerprint recognition module provided by an embodiment of the present disclosure also includes: a first insulating layer, located on a side of the multiple first driving electrodes away from the functional substrate; and an acoustic wave reflecting layer, located on a side of the first insulating layer away from the multiple first driving electrodes, the orthographic projection of the acoustic wave reflecting layer on the functional substrate overlaps with the orthographic projection of the piezoelectric material layer on the functional substrate.

[0016] For example, in a fingerprint recognition module provided in an embodiment of the present disclosure, the functional substrate includes: a substrate; a receiving electrode layer, located on a side of the piezoelectric material layer close to the substrate and including a plurality of receiving electrodes; and a driving circuit layer, located on a side of the receiving electrode close to the substrate and including a plurality of driving units, the orthographic projections of the plurality of receiving electrodes on the substrate at least partially overlap with the orthographic projections of the piezoelectric material layer on the substrate, and the orthographic projections of the plurality of receiving electrodes on the substrate at least partially overlap with the orthographic projections of the plurality of first driving electrodes on the substrate.

[0017] For example, in the fingerprint recognition module provided in an embodiment of the present disclosure, the functional substrate further includes: a second insulating layer located between the receiving electrode layer and the piezoelectric material layer.

[0018] For example, in a fingerprint recognition module provided in an embodiment of the present disclosure, the functional substrate further includes: a plurality of second driving electrodes, located between the receiving electrode layer and the driving circuit layer, the plurality of first driving electrodes and the plurality of second driving electrodes form a plurality of driving electrode pairs, and the orthographic projections of the first driving electrode and the second driving electrode in each of the driving electrode pairs on the piezoelectric material layer at least partially overlap.

[0019] At least one embodiment of the present disclosure further provides an electronic device, comprising any of the above-mentioned fingerprint recognition modules.

[0020] At least one embodiment of the present disclosure also provides a method for manufacturing a fingerprint recognition module, which includes: providing a functional substrate; forming a piezoelectric material layer on the functional substrate; forming an auxiliary structure on the functional substrate on which the piezoelectric material layer is formed; and forming a plurality of first drive electrodes on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate, each of the first drive electrodes extending along a first direction and exceeding a first edge of the piezoelectric material layer in the first direction, the plurality of first drive electrodes being arranged at intervals along a second direction, the auxiliary structure being arranged in contact with at least the first edge, the auxiliary structure including a slope portion, the thickness of the slope portion in a direction perpendicular to the functional substrate gradually decreasing in a direction from the first edge to a direction away from the center of the piezoelectric material layer, and the second direction intersecting with the first direction.

[0021] For example, in the manufacturing method of the fingerprint recognition module provided in one embodiment of the present disclosure, forming an auxiliary structure on the functional substrate on which the piezoelectric material layer is formed includes: coating liquid curing glue on the functional substrate on which the piezoelectric material layer is formed; patterning the liquid curing glue to expose at least a portion of the piezoelectric material layer; and curing the liquid curing glue, wherein the liquid curing glue is leveled and cured to form the slope portion.

[0022] For example, in the manufacturing method of the fingerprint recognition module provided by an embodiment of the present disclosure, forming an auxiliary structure on the functional substrate on which the piezoelectric material layer is formed includes: patterning the liquid curing glue to expose at least a portion of the piezoelectric material layer to form a main body located on the functional substrate and arranged in the same layer as the piezoelectric material layer, and an overlapping portion connected to the main body and located on the side of the first edge of the piezoelectric material layer away from the functional substrate.

[0023] For example, in the method for manufacturing a fingerprint recognition module provided in an embodiment of the present disclosure, the size of the overlapping portion in the first direction is greater than 200 microns.

[0024] For example, in the manufacturing method of the fingerprint recognition module provided in one embodiment of the present disclosure, forming a plurality of first driving electrodes on the side of the piezoelectric material layer and the auxiliary structure away from the functional substrate includes: forming a metal layer on the side of the piezoelectric material layer and the auxiliary structure away from the functional substrate; forming a transparent metal oxide layer on the side of the metal layer away from the piezoelectric material layer; patterning the transparent metal oxide layer to form a plurality of strip-shaped transparent metal oxides; and etching the metal layer using the plurality of strip-shaped transparent metal oxides as a mask to form the plurality of first driving electrodes.

[0025] For example, in the manufacturing method of the fingerprint recognition module provided in one embodiment of the present disclosure, forming a piezoelectric material layer on the functional substrate includes: coating a piezoelectric material on the functional substrate and crystallizing it; forming a hard mask on the crystallized piezoelectric material; and etching the crystallized piezoelectric material using the hard mask as a mask to form the piezoelectric material layer, wherein the material of the hard mask includes one or more of molybdenum, aluminum, titanium, niobium and indium tin oxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure.

[0027] Figure 1 A schematic diagram of a fingerprint recognition module emitting ultrasonic waves;

[0028] Figure 2 A schematic diagram of a fingerprint recognition module receiving ultrasonic waves;

[0029] Figure 3 A schematic diagram of a fingerprint recognition module performing fingerprint recognition;

[0030] Figure 4 It is a structural schematic diagram of a fingerprint recognition module;

[0031] Figure 5A This is a scanning electron microscope image of a piezoelectric layer in a fingerprint recognition module;

[0032] Figure 5B A scanning electron microscope image of a photoresist pattern on a conductive layer in a fingerprint recognition module;

[0033] Figure 5C A scanning electron microscope image of a plurality of first driving electrodes on a piezoelectric layer in a fingerprint recognition module;

[0034] Fig. 6A A schematic cross-sectional view of a fingerprint recognition module along a first direction provided according to an embodiment of the present disclosure;

[0035] Figure 6B A schematic cross-sectional view of a fingerprint recognition module along a second direction provided according to an embodiment of the present disclosure;

[0036] Figure 6C A schematic cross-sectional view of another fingerprint recognition module along a second direction provided according to an embodiment of the present disclosure;

[0037] Figure 7 A schematic plan view of a fingerprint recognition module provided according to an embodiment of the present disclosure;

[0038] Figure 8 A schematic diagram of the structure of another fingerprint recognition module provided according to an embodiment of the present disclosure;

[0039] Fig. 9 A schematic diagram of the structure of another fingerprint recognition module provided according to an embodiment of the present disclosure;

[0040] Fig. 10A A schematic cross-sectional view of another fingerprint recognition module along a second direction provided according to an embodiment of the present disclosure;

[0041] Fig. 10B A schematic diagram of the positional relationship between a driving electrode and a receiving electrode in another fingerprint recognition module provided according to an embodiment of the present disclosure;

[0042] Fig.11 A schematic diagram of the structure of an electronic device provided according to an embodiment of the present disclosure; and

[0043] Fig.12 The present invention is a flowchart of a method for manufacturing a fingerprint recognition module according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0045] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. "First", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0046] Figure 1 A schematic diagram of a fingerprint recognition module emitting ultrasonic waves; Figure 2 The figure is a schematic diagram of a fingerprint recognition module receiving ultrasonic waves. Figure 1As shown, the fingerprint recognition module includes an ultrasonic sensor 10; the ultrasonic sensor 10 includes an upper electrode 11, a lower electrode 12 and a piezoelectric layer 13 located between the upper electrode 11 and the lower electrode 12; the piezoelectric layer 13 is made of piezoelectric material and can be excited by voltage to produce an inverse piezoelectric effect. Figure 1 As shown, when an alternating voltage (AC voltage) is input to the upper electrode 11 and the lower electrode 12 (for example, the upper electrode 11 is grounded and an AC square wave is applied to the lower electrode 12), the piezoelectric layer 13 will deform due to the inverse piezoelectric effect or drive the membrane layers above and below the piezoelectric layer 13 to vibrate together, thereby generating ultrasonic waves and emitting them outward. It should be noted that when a cavity (for example, an air cavity) is provided on the side of the upper electrode 11 away from the piezoelectric layer 13 or the side of the lower electrode 12 away from the piezoelectric layer 13, the ultrasonic waves emitted by the ultrasonic sensor will be strengthened, so that the ultrasonic waves can be better emitted.

[0047] like Figure 2 As shown, the ultrasonic wave emitted by the ultrasonic sensor 10 is reflected by the fingerprint 500, and the reflected ultrasonic wave is converted into an alternating voltage in the piezoelectric layer; at this time, the upper electrode 11 is grounded, and the lower electrode 12 can be used as a receiving electrode to receive the alternating voltage generated by the piezoelectric layer. Since the fingerprint 500 includes valleys 510 and ridges 520, they have different reflection capabilities for ultrasonic waves (the valley 510 has a stronger reflection capability for ultrasonic waves), resulting in different intensities of ultrasonic waves reflected by the valleys 510 and the ridges 520. Therefore, the alternating voltage received by the receiving electrode can be used to determine whether the ultrasonic wave is reflected by the valley or the ridge.

[0048] Figure 3 The following is a schematic diagram of a fingerprint recognition module performing fingerprint recognition. Figure 3As shown, the fingerprint recognition module includes an upper electrode 11, a plurality of lower electrodes 12, a piezoelectric layer 13 located between the upper electrode 11 and the plurality of lower electrodes 12, a substrate 80 located on the side of the upper electrode 11 away from the piezoelectric layer 13, and a protective layer 90 located on the side of the plurality of lower electrodes 12 away from the piezoelectric layer 13; the ultrasonic sensor 10 composed of the lower electrode 12, the piezoelectric layer 13 and the plurality of upper electrodes 11 can emit ultrasonic waves and receive ultrasonic waves, that is, the ultrasonic sensor 10 acts as both an ultrasonic transmitting sensor and an ultrasonic receiving sensor. When the fingerprint contacts the substrate 80, the ultrasonic wave emitted by the ultrasonic sensor 10 is reflected by the fingerprint 500, and the reflected ultrasonic wave is converted into an alternating voltage in the piezoelectric layer; at this time, the upper electrode 11 is grounded, and the plurality of lower electrodes 12 can be used as receiving electrodes, so as to realize receiving the alternating voltage generated by the piezoelectric layer at different positions. Since the fingerprint 500 includes valleys 510 and ridges 520, which have different reflection capabilities for ultrasound (the valleys 510 have stronger reflection capabilities for ultrasound), the intensities of ultrasound reflected by the valleys 510 and ridges 520 are different. Therefore, the position information of the valleys and ridges in the fingerprint 500 can be obtained through the alternating voltages received by the multiple lower electrodes 12, thereby realizing fingerprint recognition.

[0049] Figure 4 FIG. 1 is a schematic diagram of the structure of a fingerprint recognition module. Figure 4 As shown, the fingerprint recognition module includes a substrate 80, a CMOS backplane 70, a piezoelectric layer 13, a plurality of first drive electrodes 11 and an acoustic wave reflection layer 15; the CMOS backplane 70 may include a receiving electrode and a corresponding drive unit. In the study, the inventor of the present application noticed that in the preparation process of the above-mentioned fingerprint recognition module, it is necessary to form a conductive layer on the side of the piezoelectric layer away from the CMOS backplane, and then form a photoresist pattern on the side of the conductive layer away from the piezoelectric layer, and finally, the conductive layer is etched using the photoresist pattern as a mask to form the above-mentioned plurality of first drive electrodes. Figure 5A This is a scanning electron microscope image of a piezoelectric layer in a fingerprint recognition module; Figure 5B A scanning electron microscope image of a photoresist pattern on a conductive layer in a fingerprint recognition module; Figure 5C FIG. 1 is a scanning electron microscope image of a plurality of first driving electrodes on a piezoelectric layer in a fingerprint recognition module. Figure 5A and 5B As shown, since the slope of the edge of the piezoelectric layer is relatively large (about 90 degrees), during the process of forming the photoresist pattern (exposure and development), it is easy to produce defects such as broken wire (PR broken wire) and photoresist residue (PR residue) at the edge of the piezoelectric layer; Figure 5CAs shown, due to the large slope of the edge of the piezoelectric layer (about 90 degrees) and defects such as broken lines and photoresist residues caused by the photoresist pattern, the subsequent etching process will also cause the multiple strip-shaped driving electrodes formed by the conductive layer to be broken at the edge of the piezoelectric layer (Tx broken lines) or the conductive layer to form residual conductive material (Tx residue), thereby causing various defects.

[0050] In this regard, the embodiment of the present disclosure provides a fingerprint recognition module and a manufacturing method thereof and an electronic device. The fingerprint recognition module includes a substrate, a piezoelectric material layer, an auxiliary structure and a plurality of first drive electrodes; the piezoelectric material layer is located on the substrate, the auxiliary structure is at least partially located on the substrate, and the plurality of first drive electrodes are located on the side of the piezoelectric material and the auxiliary structure away from the substrate; each first drive electrode extends along a first direction and exceeds the first edge of the piezoelectric material layer in the first direction, the plurality of first drive electrodes are arranged at intervals along a second direction, the auxiliary structure is arranged in contact with at least the first edge, the auxiliary structure includes a slope, and the thickness of the slope in the direction perpendicular to the functional substrate gradually decreases in the direction from the first edge to the direction away from the center of the piezoelectric material layer, and the second direction intersects with the first direction. In the fingerprint recognition module, since the auxiliary structure is arranged in contact with the first edge of the piezoelectric material layer and the auxiliary structure includes a slope, problems such as disconnection and residual conductive material can be avoided in the process of forming a plurality of first drive electrodes on the piezoelectric material layer, thereby improving the yield of the product.

[0051] Hereinafter, the fingerprint recognition module, the method for manufacturing the fingerprint recognition module and the electronic device provided by the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0052] An embodiment of the present disclosure provides a fingerprint recognition module. Fig. 6A A schematic cross-sectional view of a fingerprint recognition module along a first direction provided according to an embodiment of the present disclosure; Figure 6B FIG. 1 is a schematic cross-sectional view of a fingerprint recognition module along a second direction according to an embodiment of the present disclosure. Fig. 6A and Figure 6B As shown, the fingerprint recognition module 100 includes a functional substrate 110, a piezoelectric material layer 120, an auxiliary structure 130 and a plurality of first driving electrodes 140; the piezoelectric material layer 120 is located on the functional substrate 110, and the auxiliary structure 130 is at least partially located on the functional substrate 110; the plurality of first driving electrodes 140 are located on a side of the piezoelectric material layer 120 and the auxiliary structure 130 away from the functional substrate 110. Fig. 6A As shown, each first driving electrode 140 extends along the first direction and exceeds the first edge 121 of the piezoelectric material layer 120 in the first direction, that is, each first driving electrode 140 crosses the first edge 121 of the piezoelectric material layer 120 in the first direction; Figure 6BAs shown, a plurality of first driving electrodes 140 are arranged at intervals along the second direction, and the plurality of first driving electrodes 140 are arranged insulated from each other. Fig. 6A As shown, the auxiliary structure 130 is at least arranged in contact with the first edge 121, and includes a slope 132; in the direction from the first edge 121 to the center away from the piezoelectric material layer 120, the slope 132 gradually decreases in the direction perpendicular to the functional substrate 110, and the second direction intersects with the first direction. It should be noted that the first edge of the piezoelectric material layer in the first direction refers to the extension direction of the first edge intersecting with the first direction, and the extension direction of the first edge is parallel to the first direction.

[0053] In the fingerprint recognition module provided by the embodiment of the present disclosure, since the auxiliary structure is at least arranged in contact with the first edge, the first driving electrode extending along the first direction and exceeding the first edge extends from the piezoelectric material layer to the auxiliary structure, rather than directly extending from the piezoelectric material layer to the functional substrate; in addition, the auxiliary structure includes a slope portion, and the thickness of the slope portion gradually decreases in the direction from the first edge to the center away from the piezoelectric material layer. Therefore, in the process of forming multiple first driving electrodes on the piezoelectric material layer, the photoresist can be fully exposed and developed at the first edge, thereby effectively avoiding the problem of disconnection of the conductive layer in the subsequent etching process, and also avoiding the problem of residual conductive material, thereby avoiding the electrical connection between two adjacent first driving electrodes, thereby improving the yield of the product.

[0054] In some examples, the first direction and the second direction are perpendicular to each other. Fig. 6A and Figure 6B As shown, the slope angle θ of the slope portion 132 is less than 60 degrees. This arrangement can better avoid problems such as disconnection and conductive material residue in the process of forming a plurality of first driving electrodes.

[0055] In some examples, such as Fig. 6A and Figure 6B As shown, the auxiliary structure 130 includes a main body 134 and an overlapping portion 136; the main body 134 is located on the functional substrate 110 and is arranged in the same layer as the piezoelectric material layer 120; the overlapping portion 136 is connected to the main body 134 and is located on the side of the first edge 121 of the piezoelectric material layer 120 away from the functional substrate 110. In this way, the auxiliary structure can avoid problems such as disconnection and residual conductive material in the process of forming the first driving electrode, and can also fix the piezoelectric material layer on the functional substrate through the overlapping portion, thereby preventing the piezoelectric material layer from falling off during the process of manufacturing and use.

[0056] In some examples, the material of the piezoelectric material layer includes polyvinylidene fluoride (PVDF). Since polyvinylidene fluoride is a fluorine-containing material, it has poor adhesion to the functional substrate (such as a silicon nitride layer), which causes the piezoelectric material layer to fall off easily. Therefore, by setting the above-mentioned overlapping portion, the fingerprint recognition module can effectively avoid preventing the piezoelectric material layer from falling off during the process of manufacturing and use. On the other hand, in the process of stripping the photoresist pattern (PR), the stripping liquid components of the photoresist pattern usually include N-methylformamide (NMF) and diethylene glycol monomethyl ether, and polyvinylidene fluoride is dissolved in N-methylformamide and ethers. Therefore, on the one hand, the above-mentioned auxiliary structure can protect the edge of the piezoelectric material layer in the process of stripping the photoresist pattern (PR), prevent the stripping liquid of the photoresist pattern from corroding the piezoelectric material layer, thereby preventing the piezoelectric material layer from detaching; on the other hand, the overlapping portion of the above-mentioned auxiliary structure can fix the piezoelectric material layer on the functional substrate, thereby further preventing the piezoelectric material layer from falling off during the process of manufacturing and use.

[0057] For example, Fig. 6A and Figure 6B As shown, the main body 134 includes the above-mentioned slope portion 132 . In other words, the slope portion 132 is a part of the main body 134 .

[0058] In some examples, the size of the overlapping portion 136 in the first direction is greater than 200 microns. According to experimental results, when the size of the overlapping portion in the first direction is greater than 200 microns, the auxiliary structure can effectively prevent the piezoelectric material layer from falling off during the manufacturing and use process. For example, the size of the overlapping portion in the first direction can be 400, 600, 800, 1000 or 1500 microns.

[0059] In some examples, the material of the auxiliary structure includes curing glue. Therefore, in the process of forming the auxiliary structure, after applying the curing glue and before curing the auxiliary structure, the curing glue will undergo a leveling process due to its certain fluidity or ductility, thereby naturally forming the above-mentioned slope portion, thereby eliminating the need for additional process steps, thereby reducing the difficulty and cost of production. For example, when the auxiliary structure uses curing glue, the slope angle of the formed slope portion is about 45 degrees.

[0060] In some examples, the material of the auxiliary structure includes optical curing glue (OC glue). Therefore, the auxiliary structure can be patterned directly through an exposure process without using a mask process, thereby further reducing the production cost. For example, the material of the auxiliary structure can be an acrylate system material.

[0061] In some examples, such as Fig. 6A and Figure 6BAs shown, the fingerprint recognition module 100 further includes a first insulating layer 151 and an acoustic wave reflecting layer 160; the first insulating layer 151 is located on a side of the plurality of first driving electrodes 140 away from the functional substrate 110; the acoustic wave reflecting layer 160 is located on a side of the first insulating layer 151 away from the plurality of first driving electrodes 140, and the orthographic projection of the acoustic wave reflecting layer 160 on the functional substrate 110 overlaps with the orthographic projection of the piezoelectric material layer 120 on the functional substrate 110. In this arrangement, the acoustic wave reflecting layer 160 can reflect the ultrasonic wave generated by the piezoelectric material layer 120 and propagating toward the acoustic wave reflecting layer 160 to the position where the functional substrate 110 is located, thereby facilitating the enhancement of the intensity or energy of the emitted ultrasonic wave.

[0062] For example, the sound wave reflection layer 160 can be made of silver (Ag), and the first insulating layer 151 can be made of silicon nitride (SiNx). Of course, the embodiments of the present disclosure include but are not limited to this, the sound wave reflection layer can also be made of other materials with the property of reflecting ultrasonic waves, and the first insulating layer can also be made of other insulating materials such as resin.

[0063] In some examples, such as Fig. 6A and Figure 6B As shown, the functional substrate 110 includes a receiving electrode layer 170, a driving circuit layer 180 and a substrate 190; the receiving electrode layer 170 is located on the side of the piezoelectric material layer 120 close to the substrate 190 and includes a plurality of receiving electrodes 175; the driving circuit layer 180 is located on the side of the receiving electrode 170 close to the substrate 190 and includes a plurality of driving units 185, and the plurality of receiving electrodes 175 are arranged in a one-to-one correspondence with the plurality of driving units 185, and the plurality of driving units 185 are configured to drive the plurality of receiving electrodes 175 to receive the electrical signal generated by the piezoelectric material layer 120. The orthographic projections of the plurality of receiving electrodes 175 on the substrate 190 at least partially overlap with the orthographic projections of the piezoelectric material layer 120 on the substrate 110; the orthographic projections of the plurality of receiving electrodes 175 on the substrate 190 at least partially overlap with the orthographic projections of the plurality of first driving electrodes 140 on the substrate 190, thereby forming a plurality of ultrasonic receiving elements with the first driving electrodes 140 and the piezoelectric material layer 120.

[0064] For example, Fig. 6A and Figure 6B As shown, an insulating layer is disposed between the multiple receiving electrodes 170 to ensure mutual insulation; similarly, an insulating layer is also disposed between the multiple driving units 185 to ensure mutual insulation.

[0065] In the fingerprint recognition module provided in this embodiment, the multiple first driving electrodes, the piezoelectric material layer and the multiple receiving electrodes arranged on the piezoelectric material layer can constitute multiple ultrasonic emitting elements; the multiple receiving electrodes, the piezoelectric material layer and the multiple first driving electrodes can constitute multiple ultrasonic receiving elements. When the fingerprint recognition module performs fingerprint recognition, the multiple receiving electrodes can be grounded, and then an alternating voltage is applied to the multiple first driving electrodes respectively. The piezoelectric material layer corresponding to the first driving electrode will deform due to the inverse piezoelectric effect or drive the film layer above and below the piezoelectric material layer to vibrate together, thereby generating ultrasonic waves and emitting them outward. Since the first driving electrode layer of the fingerprint recognition module includes multiple first driving electrodes, multiple ultrasonic emitting elements can be constituted, so that the focusing of ultrasonic waves can be achieved by driving the above-mentioned multiple first driving electrodes respectively. On the one hand, the intensity or energy of the emitted ultrasonic waves in a specific area or specific direction can be increased, thereby improving the fingerprint recognition performance. On the other hand, the emitted ultrasonic waves can have better directionality, thereby reducing the crosstalk between the valleys and ridges of the fingerprint, thereby improving the fingerprint recognition performance. When the emitted ultrasonic wave is reflected back to the fingerprint recognition module by the fingerprint, the multiple ultrasonic receiving elements corresponding to the multiple receiving electrodes can receive the reflected ultrasonic wave and convert the ultrasonic wave signal into an electrical signal, thereby realizing fingerprint recognition. In addition, when the fingerprint recognition module improves the intensity or energy of the emitted ultrasonic wave in a specific area or specific direction by realizing the focusing of the ultrasonic wave, the fingerprint recognition module can not only realize fingerprint recognition, but also penetrate the finger to distinguish whether the fingerprint is real skin.

[0066] In some examples, such as Fig. 6A and Figure 6B As shown, the receiving electrode 175 and the piezoelectric material layer 120 can be arranged in contact with each other, so as to better receive the electrical signal. Of course, the embodiments of the present disclosure include but are not limited to this.

[0067] Figure 6C FIG. 2 is a cross-sectional schematic diagram of another fingerprint recognition module provided along the second direction according to an embodiment of the present disclosure. Figure 6C As shown, the functional substrate 110 further includes: a second insulating layer 152, which is located between the receiving electrode layer 170 and the piezoelectric material layer 120. The second insulating layer 152 can reduce the influence of the leakage current generated by the piezoelectric material layer 120 during polarization on the thin film transistor in the driving unit 185 connected to the receiving electrode 175. For example, the second insulating layer can also be made of silicon nitride (SiNx).

[0068] In some examples, substrate 190 includes a glass substrate.

[0069] In some examples, the substrate 190 includes a polyimide substrate. Thus, the substrate 190 can be made thinner, and the thickness of the substrate 190 ranges from 5 to 20 microns. It should be noted that when the substrate 190 is a polyimide substrate, a polyimide layer can be first formed on a glass substrate, and then a receiving electrode layer, a piezoelectric material layer, a first driving electrode layer and other layer structures can be formed on the polyimide layer, and finally the glass substrate is removed to obtain the fingerprint recognition module described in this example.

[0070] Figure 7 FIG. 1 is a schematic plan view of a fingerprint recognition module provided according to an embodiment of the present disclosure. Figure 7 As shown, the auxiliary structure 130 is arranged along the edge of the piezoelectric material 120, and the auxiliary structure 130 is also arranged in contact with the second edge 122 of the piezoelectric material layer 120 in the second direction. In this way, the auxiliary structure can provide all-round protection for the edge of the piezoelectric material layer in the process of stripping the photoresist pattern (PR), better prevent the stripping liquid of the photoresist pattern from corroding the piezoelectric material layer, and thus better avoid the piezoelectric material layer from detaching. Of course, the embodiments of the present disclosure include but are not limited to this, and the auxiliary structure can also be arranged only on the first edge of the piezoelectric material along the first direction. It should be noted that the second edge of the above-mentioned piezoelectric material layer in the second direction refers to the extension direction of the second edge intersecting with the second direction, and the extension direction of the second edge is parallel to the second direction.

[0071] For example, Figure 7 As shown, the shape of the orthographic projection of the piezoelectric material layer 120 on the functional substrate 110 may include a rectangle, such as a square. The auxiliary structure 130 is arranged along the four edges of the piezoelectric material layer 120. Of course, the embodiments of the present disclosure include but are not limited to this, and the shape of the piezoelectric material layer can be set according to actual needs; the auxiliary structure can also be arranged only on the first edge of the piezoelectric material layer in the first direction.

[0072] Figure 8 FIG. 1 is a schematic diagram of the structure of another fingerprint recognition module provided according to an embodiment of the present disclosure. Figure 8 As shown, each first driving electrode 140 includes a metal layer 142 and a transparent metal oxide layer 144 stacked in sequence in a direction perpendicular to the functional substrate. Since the stripping solution components of the photoresist pattern usually include N-methylformamide (NMF) and diethylene glycol monomethyl ether, and polyvinylidene fluoride is dissolved in N-methylformamide and ethers. Therefore, the above-mentioned transparent metal oxide layer can be used as a mask in the process of forming the first driving electrode, thereby preventing the stripping solution of the photoresist pattern from corroding the piezoelectric material layer. It should be noted that the etching solution of the common transparent metal oxide layer cannot etch the metal layer, and the etching solution of the metal layer cannot etch the transparent metal oxide layer, so the transparent metal oxide layer can be used as a mask to etch the metal layer.

[0073] This is explained below through a specific manufacturing process of the first driving electrode. For example, forming a plurality of first driving electrodes on the side of the piezoelectric material layer and the auxiliary structure away from the functional substrate includes the following steps: forming a metal layer on the side of the piezoelectric material layer and the auxiliary structure away from the functional substrate; forming a transparent metal oxide layer on the side of the metal layer away from the piezoelectric material layer; forming a photoresist pattern on the side of the transparent metal oxide layer away from the metal layer, patterning the transparent metal oxide layer with the photoresist pattern as a mask to form a plurality of strip-shaped transparent metal oxides; stripping the above-mentioned photoresist pattern; and etching the metal layer with the plurality of strip-shaped transparent metal oxides as a mask to form a plurality of first driving electrodes. It can be seen that in the above-mentioned manufacturing process, when the photoresist pattern is stripped, the metal layer still covers the piezoelectric material layer, thereby avoiding contact between the stripping liquid and the piezoelectric material layer. Therefore, the stripping liquid of the photoresist pattern can be prevented from corroding the piezoelectric material layer.

[0074] For example, the transparent metal oxide may include indium tin oxide (ITO). Of course, the embodiments of the present disclosure include but are not limited to this, and the transparent metal oxide may also be other specific materials.

[0075] In some examples, the thickness of the transparent metal oxide layer is in the range of Since the piezoelectric material layer is usually a porous material with a rough surface, the surface of the metal layer will appear uneven. In this way, the transparent metal oxide layer can better cover the metal layer.

[0076] Fig. 9 FIG. 1 is a schematic diagram of the structure of another fingerprint recognition module provided according to an embodiment of the present disclosure. Fig. 9 As shown, the fingerprint recognition module 100 includes a functional substrate 110, a piezoelectric material layer 120, an auxiliary structure 130 and a plurality of first driving electrodes 140; the piezoelectric material layer 120 is located on the functional substrate 110, and the auxiliary structure 130 is at least partially located on the functional substrate 110; the plurality of first driving electrodes 140 are located on the side of the piezoelectric material layer 120 and the auxiliary structure 130 away from the functional substrate 110. Each first driving electrode 140 extends along a first direction and exceeds a first edge 121 of the piezoelectric material layer 120 in the first direction; the plurality of first driving electrodes 140 are spaced apart along a second direction, and the plurality of first driving electrodes 140 are insulated from each other. The auxiliary structure 130 is arranged in contact with the first edge 121, and includes a slope portion 132; in a direction from the first edge 121 to a direction away from the center of the piezoelectric material layer 120, the thickness of the slope portion 132 in a direction perpendicular to the functional substrate 110 gradually decreases. As shown Fig. 9As shown, the auxiliary structure 130 only includes a main body 134 located on the functional substrate 110 and arranged in the same layer as the piezoelectric material layer 120, but does not include an overlapping portion 136. In this way, the auxiliary structure can effectively avoid the problem of disconnection of the conductive layer in the subsequent etching process, and can also avoid the problem of residual conductive material, thereby avoiding the electrical connection between two adjacent first drive electrodes, thereby improving the yield of the product. In addition, although no overlapping portion is provided, the auxiliary structure can protect the edge of the piezoelectric material layer in the process of stripping the photoresist pattern (PR), thereby preventing the piezoelectric material layer from detaching.

[0077] An embodiment of the present disclosure provides a fingerprint recognition module. Fig. 10A A schematic cross-sectional view of another fingerprint recognition module along a second direction provided according to an embodiment of the present disclosure; Fig. 10B FIG. 1 is a schematic diagram of the positional relationship between the driving electrode and the receiving electrode in another fingerprint recognition module provided according to an embodiment of the present disclosure. Fig. 10A As shown, the fingerprint recognition module 100 includes a functional substrate 110, a piezoelectric material layer 120, an auxiliary structure 130 and a plurality of first driving electrodes 140; the piezoelectric material layer 120 is located on the functional substrate 110, and the auxiliary structure 130 is at least partially located on the functional substrate 110; the plurality of first driving electrodes 140 are located on the side of the piezoelectric material layer 120 and the auxiliary structure 130 away from the functional substrate 110. The functional substrate 110 includes a substrate receiving electrode layer 170, a driving circuit layer 180 and a substrate 190; the receiving electrode layer 170 is located on the side of the piezoelectric material layer 120 close to the substrate 190 and includes a plurality of receiving electrodes 175; the driving circuit layer 180 is located on the side of the receiving electrode 170 close to the substrate 190 and includes a plurality of driving units 185, the plurality of receiving electrodes 175 are arranged one by one with the plurality of driving units 185, and the plurality of driving units 185 are configured to drive the plurality of receiving electrodes 175 to receive the electrical signal generated by the piezoelectric material layer 120. The orthographic projections of the plurality of receiving electrodes 175 on the substrate 190 at least partially overlap with the orthographic projection of the piezoelectric material layer 120 on the substrate 110 .

[0078] like Fig. 10A and Fig. 10BAs shown, the functional substrate 110 also includes a plurality of second driving electrodes 240, which are located between the receiving electrode layer 170 and the driving circuit layer 180. The plurality of first driving electrodes 140 and the plurality of second driving electrodes 240 form a plurality of driving electrode pairs 40, and the orthographic projections of the first driving electrode 140 and the second driving electrode 240 in each driving electrode pair 40 on the piezoelectric material layer 120 at least partially overlap. In this way, the first driving electrode and the second driving electrode in each driving electrode pair and the piezoelectric material layer can constitute an ultrasonic emitting element, thereby realizing ultrasonic emission. In addition, the fingerprint recognition module can also apply a first driving voltage (e.g., +50V) to the first driving electrode and a second driving voltage (e.g., -50V) with opposite polarity to the second driving electrode, thereby realizing high-voltage drive or high-voltage excitation of the piezoelectric material layer with a lower driving voltage (absolute value). Therefore, the fingerprint recognition module can realize high-voltage driving or high-voltage excitation of the piezoelectric material layer with a lower driving voltage (absolute value), which can greatly reduce the risk of breakdown of electronic components (such as thin film transistors) in the driving unit due to high voltage, thereby improving the stability and durability of the product, and on the other hand, it is also conducive to the realization of a large-size fingerprint recognition module. It should be noted that since the receiving electrode is electrically connected to the driving unit, the driving voltage cannot be directly applied to the receiving electrode. Therefore, the fingerprint recognition module provided in this example cleverly sets a plurality of second driving electrodes and forms a plurality of driving electrode pairs with a plurality of first driving electrodes to realize high-voltage driving or high-voltage excitation of the piezoelectric material layer with a lower driving voltage (absolute value).

[0079] In some examples, such as Fig. 10B As shown, multiple receiving electrodes 175 are arranged in an array along the first direction and the second direction, multiple first driving electrodes 140 are arranged along the second direction, and second driving electrodes 240 are arranged along the second direction. Each first driving electrode 140 and each second driving electrode 240 is a strip electrode extending along the first direction.

[0080] In some examples, such as Fig. 10A and 10B As shown, the orthographic projection of each second driving electrode 240 on the piezoelectric material layer 120 at least partially overlaps with the orthographic projection of the plurality of receiving electrodes 175 arranged along the first direction on the piezoelectric material layer 120. The fingerprint recognition module 100 further includes a plurality of connecting electrodes 250, each second driving electrode 240 includes a plurality of through holes 245, and the plurality of connecting electrodes 250 are respectively disposed in the plurality of through holes 245 and respectively electrically connect the plurality of receiving electrodes 175 to the plurality of driving units 185. In this arrangement, the receiving electrode can better receive the electrical signal generated by the piezoelectric material layer due to receiving the ultrasonic wave, thereby improving the accuracy of fingerprint recognition.

[0081] An embodiment of the present disclosure further provides an electronic device. Fig.11 FIG. 1 is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present disclosure. Fig.11 As shown, the electronic device 300 includes the above-mentioned fingerprint recognition module 100. Thus, the electronic device can realize the fingerprint recognition function. In addition, since the fingerprint recognition module included therein can effectively avoid the problem of disconnection and residual conductive material in the conductive layer in the subsequent etching process, the electronic device has a good yield and performance.

[0082] For example, in some examples, such as Fig.11 As shown, the display device 300 also includes a display module 310, and the area of ​​the display module 310 is substantially the same as the area of ​​the fingerprint recognition module 100, so that full-screen fingerprint recognition can be achieved. At this time, the fingerprint recognition module can also realize the touch function, so that there is no need to set up an additional touch device, such as a capacitive touch panel, thereby reducing the cost of the display device. Of course, the embodiments of the present disclosure include but are not limited to this, and the area of ​​the display module may not be equal to the area of ​​the fingerprint recognition module, and the fingerprint recognition module may only be set in the area where fingerprint recognition is required.

[0083] In some examples, the electronic device may be a display device, for example, a television, a mobile phone, a computer, a laptop, an electronic photo album, a navigator, or other electronic device with a display function.

[0084] An embodiment of the present disclosure also provides a method for manufacturing a fingerprint recognition module. Fig.12 FIG. 1 is a flow chart of a method for manufacturing a fingerprint recognition module according to an embodiment of the present disclosure. Fig.12 As shown, the method for manufacturing the fingerprint recognition module includes the following steps S101-S104.

[0085] Step S101: providing a functional substrate.

[0086] Step S102: forming a piezoelectric material layer on the functional substrate. For example, the piezoelectric material layer can be made of a piezoelectric material with a relatively high piezoelectric voltage constant, such as polyvinylidene fluoride (PVDF).

[0087] Step S103: forming an auxiliary structure on the functional substrate having the piezoelectric material layer formed thereon.

[0088] Step S104: A plurality of first driving electrodes are formed on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate, each first driving electrode extends along a first direction and exceeds a first edge of the piezoelectric material layer in the first direction, a plurality of first driving electrodes are spaced apart along a second direction, the auxiliary structure is at least in contact with the first edge, the auxiliary structure includes a slope portion, and a thickness of the slope portion in a direction perpendicular to the functional substrate gradually decreases in a direction from the first edge to a direction away from the center of the piezoelectric material layer, and the second direction intersects with the first direction.

[0089] In the method for manufacturing the fingerprint recognition module provided by the embodiment of the present disclosure, since the auxiliary structure is at least arranged in contact with the first edge, the first driving electrode extending along the first direction and exceeding the first edge extends from the piezoelectric material layer to the auxiliary structure, rather than directly extending from the piezoelectric material layer to the functional substrate; in addition, the auxiliary structure includes a slope portion, and the thickness of the slope portion gradually decreases in the direction from the first edge to the center away from the piezoelectric material layer. Therefore, in the process of forming multiple first driving electrodes on the piezoelectric material layer, the photoresist can be fully exposed and developed at the first edge, thereby effectively avoiding the problem of disconnection of the conductive layer in the subsequent etching process, and also avoiding the problem of residual conductive material, thereby avoiding the electrical connection between two adjacent first driving electrodes, thereby improving the yield of the product.

[0090] In some examples, forming an auxiliary structure on a functional substrate having a piezoelectric material layer includes: coating a liquid curing glue on the functional substrate having a piezoelectric material layer; patterning the liquid curing glue to expose at least a portion of the piezoelectric material layer; and curing the liquid curing glue, wherein the liquid curing glue is leveled and cured to form a slope. Thus, in the process of forming the auxiliary structure, the liquid curing glue has a certain fluidity or ductility, and the liquid curing glue undergoes a leveling process, thereby naturally forming the above-mentioned slope, thereby eliminating the need for additional process steps, thereby reducing the difficulty and cost of manufacturing.

[0091] For example, the first direction and the second direction mentioned above may be perpendicular to each other.

[0092] In some examples, the material of the auxiliary structure includes an optical curing glue (OC glue). Thus, the step of patterning the liquid curing glue to expose at least a portion of the piezoelectric material layer can be directly patterned by an exposure process without using a mask process, thereby further reducing the manufacturing cost. For example, the material of the auxiliary structure can be an acrylate system material.

[0093] For example, the liquid curing adhesive may be cured by heat curing. Of course, the embodiments of the present disclosure include but are not limited to this, and other curing methods may also be used to cure the liquid curing adhesive.

[0094] For example, the auxiliary structure may be made of a material that can be cured at low temperatures; for example, the curing temperature is less than 130 degrees Celsius. This arrangement can prevent high temperatures from having adverse effects on other structures of the fingerprint recognition module.

[0095] In some examples, forming an auxiliary structure on a functional substrate having a piezoelectric material layer formed thereon includes: patterning a liquid curing adhesive to expose at least a portion of the piezoelectric material layer to form a main body portion located on the functional substrate and disposed in the same layer as the piezoelectric material layer, and an overlapping portion connected to the main body portion and located on a side of the first edge of the piezoelectric material layer away from the functional substrate. In this way, the auxiliary structure can avoid problems such as disconnection and residual conductive material during the formation of the first drive electrode, and can also fix the piezoelectric material layer on the functional substrate through the overlapping portion, thereby preventing the piezoelectric material layer from falling off during the production and use process.

[0096] In some examples, when the material of the piezoelectric material layer includes polyvinylidene fluoride (PVDF), since polyvinylidene fluoride is a fluorine-containing material, the adhesion to the functional substrate (such as a silicon nitride layer) is poor, causing the piezoelectric material layer to fall off easily. Therefore, by forming the above-mentioned overlapping portion, the manufacturing method of the fingerprint recognition module can effectively avoid preventing the piezoelectric material layer from falling off during the manufacturing process. On the other hand, in the process of stripping the photoresist pattern (PR), the stripping liquid components of the photoresist pattern usually include N-methylformamide (NMF) and diethylene glycol monomethyl ether, and polyvinylidene fluoride is dissolved in N-methylformamide and ethers. Therefore, on the one hand, the above-mentioned auxiliary structure can protect the edge of the piezoelectric material layer in the process of stripping the photoresist pattern (PR) to prevent the stripping liquid of the photoresist pattern from corroding the piezoelectric material layer, thereby preventing the piezoelectric material layer from detaching; on the other hand, the overlapping portion of the above-mentioned auxiliary structure can fix the piezoelectric material layer on the functional substrate, thereby further preventing the piezoelectric material layer from falling off during the manufacturing process.

[0097] In some examples, the size of the overlapping portion in the first direction is greater than 200 microns. According to experimental results, when the size of the overlapping portion in the first direction is greater than 200 microns, the auxiliary structure can effectively prevent the piezoelectric material layer from falling off during the manufacturing and use process. For example, the size of the overlapping portion in the first direction can be 400, 600, 800, 1000 or 1500 microns.

[0098] In some examples, forming a plurality of first driving electrodes on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate includes: forming a metal layer on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate; forming a transparent metal oxide layer on a side of the metal layer away from the piezoelectric material layer; patterning the transparent metal oxide layer to form a plurality of strip-shaped transparent metal oxides; and etching the metal layer using the plurality of strip-shaped transparent metal oxides as a mask to form a plurality of first driving electrodes. Thus, when the photoresist pattern is stripped, the metal layer still covers the piezoelectric material layer, thereby preventing the stripping solution of the photoresist pattern from corroding the piezoelectric material layer.

[0099] For example, patterning the transparent metal oxide layer to form a plurality of strip-shaped transparent metal oxides includes: forming a photoresist pattern on a side of the transparent metal oxide layer away from the metal layer; patterning the transparent metal oxide layer using the photoresist pattern as a mask to form a plurality of strip-shaped transparent metal oxides; and stripping the photoresist pattern. It can be seen that in the above-mentioned manufacturing process, when the photoresist pattern is stripped, the metal layer still covers the piezoelectric material layer, so that the stripping solution of the photoresist pattern can be prevented from corroding the piezoelectric material layer.

[0100] For example, the transparent metal oxide may include indium tin oxide (ITO).

[0101] In some examples, the thickness of the transparent metal oxide layer is in the range of Since the piezoelectric material layer is usually a porous material with a rough surface, the surface of the metal layer will be uneven. In this way, the transparent metal oxide layer can better cover the metal layer.

[0102] In some examples, forming a piezoelectric material layer on a functional substrate includes: coating a piezoelectric material on the functional substrate and crystallizing it; forming a hard mask on the crystallized piezoelectric material; and etching the crystallized piezoelectric material using the hard mask as a mask to form a piezoelectric material layer, wherein the material of the hard mask includes one or more of molybdenum, aluminum, titanium, niobium, and indium tin oxide. Thus, by using a hard mask, the stripping solution of the photoresist pattern can be prevented from corroding the piezoelectric material layer to a certain extent, so as to improve the quality of the piezoelectric material layer, thereby improving the performance of the fingerprint recognition module.

[0103] There are a few points to note:

[0104] (1) In the drawings of the embodiments of the present disclosure, only the structures related to the embodiments of the present disclosure are involved, and other structures can refer to the general design.

[0105] (2) In the absence of conflict, features in the same embodiment or in different embodiments of the present disclosure may be combined with each other.

[0106] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A fingerprint recognition module, comprising: Functional substrate; A piezoelectric material layer is located on the functional substrate; an auxiliary structure, at least partially located on the functional substrate; as well as A plurality of first driving electrodes are located on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate, Each of the first driving electrodes extends along a first direction and exceeds a first edge of the piezoelectric material layer in the first direction, the plurality of first driving electrodes are arranged at intervals along a second direction, the auxiliary structure is arranged in contact with at least the first edge, the auxiliary structure comprises a slope portion, and in a direction from the first edge to a direction away from the center of the piezoelectric material layer, the thickness of the slope portion in a direction perpendicular to the functional substrate gradually decreases, and the second direction intersects with the first direction, The fingerprint recognition module also includes: a first insulating layer, located on a side of the multiple first driving electrodes away from the functional substrate; and an acoustic wave reflecting layer, located on a side of the first insulating layer away from the multiple first driving electrodes, the orthographic projection of the acoustic wave reflecting layer on the functional substrate overlaps with the orthographic projection of the piezoelectric material layer on the functional substrate.

2. The fingerprint recognition module according to claim 1, wherein: The slope angle of the slope portion is less than 60 degrees.

3. The fingerprint recognition module according to claim 1, wherein: The auxiliary structure comprises: A main body, located on the functional substrate and arranged on the same layer as the piezoelectric material layer; and The overlapping portion is connected to the main body portion and is located on a side of the first edge of the piezoelectric material layer away from the functional substrate.

4. The fingerprint recognition module according to claim 3, wherein: A dimension of the overlapping portion in the first direction is greater than 200 micrometers.

5. The fingerprint recognition module according to any one of claims 1 to 4, wherein: The material of the auxiliary structure includes curing glue.

6. The fingerprint recognition module according to any one of claims 1 to 4, wherein: The material of the auxiliary structure includes optical curing glue.

7. The fingerprint recognition module according to any one of claims 1 to 4, wherein: The material of the piezoelectric material layer includes polyvinylidene fluoride.

8. The fingerprint recognition module according to any one of claims 1 to 4, wherein: The auxiliary structure is arranged along the edge of the piezoelectric material, and the auxiliary structure is also arranged in contact with the second edge of the piezoelectric material layer in the second direction.

9. The fingerprint recognition module according to any one of claims 1 to 4, wherein: Each of the first driving electrodes includes a metal layer and a transparent metal oxide layer sequentially stacked in a direction perpendicular to the functional substrate.

10. The fingerprint recognition module according to any one of claims 1 to 4, wherein: The functional substrate comprises: substrate; a receiving electrode layer, located on a side of the piezoelectric material layer close to the substrate and comprising a plurality of receiving electrodes; and The driving circuit layer is located on a side of the receiving electrode close to the substrate and includes a plurality of driving units. The orthographic projections of the plurality of receiving electrodes on the substrate at least partially overlap with the orthographic projections of the piezoelectric material layer on the substrate, and the orthographic projections of the plurality of receiving electrodes on the substrate at least partially overlap with the orthographic projections of the plurality of first driving electrodes on the substrate.

11. The fingerprint recognition module according to claim 10, wherein: The functional substrate further comprises: The second insulating layer is located between the receiving electrode layer and the piezoelectric material layer.

12. The fingerprint recognition module according to claim 10, wherein: The functional substrate further comprises: A plurality of second driving electrodes are located between the receiving electrode layer and the driving circuit layer, The plurality of first driving electrodes and the plurality of second driving electrodes form a plurality of driving electrode pairs, and the orthographic projections of the first driving electrode and the second driving electrode in each of the driving electrode pairs on the piezoelectric material layer at least partially overlap.

13. An electronic device comprising the fingerprint recognition module according to any one of claims 1-12.

14. A method for manufacturing a fingerprint recognition module, comprising: Providing a functional substrate; forming a piezoelectric material layer on the functional substrate; forming an auxiliary structure on the functional substrate having the piezoelectric material layer formed thereon; as well as A plurality of first driving electrodes are formed on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate, Wherein, each of the first driving electrodes extends along the first direction and exceeds the first edge of the piezoelectric material layer in the first direction, the plurality of first driving electrodes are arranged at intervals along the second direction, the auxiliary structure is arranged in contact with at least the first edge, the auxiliary structure includes a slope portion, the thickness of the slope portion gradually decreases in a direction from the first edge to a direction away from the center of the piezoelectric material layer, the thickness of the slope portion gradually decreases in a direction perpendicular to the functional substrate, and the second direction intersects with the first direction, The fingerprint recognition module also includes: a first insulating layer, located on a side of the multiple first driving electrodes away from the functional substrate; and an acoustic wave reflecting layer, located on a side of the first insulating layer away from the multiple first driving electrodes, the orthographic projection of the acoustic wave reflecting layer on the functional substrate overlaps with the orthographic projection of the piezoelectric material layer on the functional substrate.

15. The method for manufacturing a fingerprint recognition module according to claim 14, wherein: Forming an auxiliary structure on the functional substrate having the piezoelectric material layer formed thereon comprises: Coating a liquid curing adhesive on the functional substrate having the piezoelectric material layer formed thereon; Patterning the liquid curing adhesive to expose at least a portion of the piezoelectric material layer; and Curing the liquid curing adhesive, The liquid curing adhesive is leveled and cured to form the slope portion.

16. The method for manufacturing a fingerprint recognition module according to claim 15, wherein: Forming an auxiliary structure on the functional substrate having the piezoelectric material layer formed thereon comprises: The liquid curing glue is patterned to expose at least a portion of the piezoelectric material layer to form a main body located on the functional substrate and arranged in the same layer as the piezoelectric material layer, and an overlapping portion connected to the main body and located on a side of the first edge of the piezoelectric material layer away from the functional substrate.

17. The method for manufacturing a fingerprint recognition module according to claim 16, wherein: A dimension of the overlapping portion in the first direction is greater than 200 micrometers.

18. The method for manufacturing a fingerprint recognition module according to any one of claims 14 to 17, wherein: Forming a plurality of first driving electrodes on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate comprises: forming a metal layer on a side of the piezoelectric material layer and the auxiliary structure away from the functional substrate; forming a transparent metal oxide layer on a side of the metal layer away from the piezoelectric material layer; patterning the transparent metal oxide layer to form a plurality of strip-shaped transparent metal oxides; and The metal layer is etched using the plurality of strip-shaped transparent metal oxides as masks to form the plurality of first driving electrodes.

19. The method for manufacturing a fingerprint recognition module according to any one of claims 14 to 17, wherein: Forming a piezoelectric material layer on the functional substrate includes: coating a piezoelectric material on the functional substrate and crystallizing the piezoelectric material; forming a hard mask on the crystallized piezoelectric material; and The crystallized piezoelectric material is etched using the hard mask as a mask to form the piezoelectric material layer. Wherein, the material of the hard mask includes one or more of molybdenum, aluminum, titanium, niobium and indium tin oxide.

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