Ultrasonic transducer, manufacturing method thereof, display panel and display device
Patent Information
- Application Number
- CN202380010867.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-25
- Publication Date
- 2025-06-06
AI Technical Summary
The application of CMUT in the field of ultrasonic imaging has attracted attention, but its cavity production is difficult and the problem of low yield has not been effectively solved.
An ultrasonic transducer structure is adopted, including a driving back plate, a first conductive layer, a first inorganic layer, a second conductive layer and a first inorganic filling part. The cavity and the etching cavity are formed by wet etching the sacrificial layer, and the through holes are encapsulated and etched through the thin film deposition process to improve product yield.
The etching vias by encapsulating and etching the vias by inorganic material is avoided from cavity blockage caused by flow of organic materials, and the product yield of ultrasonic transducers is significantly improved.
Smart Images
Figure CN120112367A_ABST
Abstract
Description
Ultrasonic transducer and manufacturing method thereof, display panel and display device Technical Field
[0001] The present disclosure relates to the field of sensing technology, and in particular to an ultrasonic transducer and a manufacturing method thereof, a display panel, and a display device. Background Art
[0002] Fingerprint recognition technology is widely used in mobile devices such as mobile phones and tablets, as well as in security systems such as access control systems and safes. Currently, fingerprint acquisition is primarily accomplished through optical, capacitive, and ultrasonic imaging methods. Ultrasonic fingerprint recognition technology, in particular, features 3D fingerprint acquisition and eliminates the need for the user's finger to touch the fingerprint acquisition device, improving recognition security and user experience.
[0003] Ultrasonic fingerprint recognition technology often uses piezoelectric micromachined ultrasonic transducers (PMUTs) or capacitive micromachined ultrasonic transducers (CMUTs) as ultrasonic transmitters and receivers. Compared to traditional PMUTs, CMUTs offer greater signal bandwidth and penetration, and have garnered significant attention in the field of ultrasonic imaging. However, CMUTs currently suffer from difficulties in cavity fabrication and low yield rates.
[0004] Summary of the Invention
[0005] The present disclosure provides an ultrasonic transducer and a manufacturing method thereof, a display panel, and a display device, for improving product yield.
[0006] In a first aspect of the present disclosure, an ultrasonic transducer is provided, comprising:
[0007] Driver backplane;
[0008] A first conductive layer is located on the driving backplane; the first conductive layer includes a first electrode, and the first electrode is electrically connected to the driving backplane;
[0009] The first inorganic layer is located on a side of the first conductive layer away from the driving backplane; a vibration cavity and an etching cavity are formed between the first inorganic layer and the first conductive layer; the first inorganic layer has an etching via that penetrates the first inorganic layer in a direction perpendicular to the driving backplane; the etching cavity is respectively connected to the vibration cavity and the etching via to form an etching channel;
[0010] A second conductive layer is located on a side of the first inorganic layer away from the driving back plate; the second conductive layer includes a second electrode;
[0011] The first inorganic filling part is located in the etching cavity and the etching via hole to block the etching via hole; the material of the first inorganic filling part is an inorganic material.
[0012] In the ultrasonic transducer provided by the present disclosure, the thickness of the second conductive layer is greater than or equal to the depth of the etching cavity; and the first inorganic filling part is located in the second conductive layer.
[0013] In the ultrasonic transducer provided in the present disclosure, the ultrasonic transducer further includes:
[0014] The first flat layer is located on a side of the second conductive layer facing away from the driving back plate; the orthographic projection of the first flat layer on the driving back plate does not overlap with the orthographic projection of the vibration cavity on the driving back plate;
[0015] The second inorganic layer is located on a side of the first flat layer away from the driving back plate and covers the first flat layer and the second conductive layer.
[0016] In the ultrasonic transducer provided by the present disclosure, the height of the first inorganic layer in the region overlapping with the vibration cavity is greater than the height of other regions of the first inorganic layer;
[0017] The height of the first flat layer is less than or equal to the height of the first inorganic layer in the region overlapping with the vibration cavity, so as to expose the surface of the first inorganic layer in the region overlapping with the vibration cavity.
[0018] In the ultrasonic transducer provided by the present disclosure, the thickness of the second conductive layer is smaller than the depth of the vibration cavity;
[0019] Ultrasonic transducers also include:
[0020] The third inorganic layer is located on a side of the first inorganic layer away from the driving back plate; the first inorganic filling part is located in the third inorganic layer.
[0021] In the ultrasonic transducer provided by the present disclosure, the third inorganic layer is located between the second conductive layer and the first inorganic layer; and the thickness of the third inorganic layer is greater than or equal to the depth of the etching cavity.
[0022] In the ultrasonic transducer provided by the present disclosure, the thickness of the third inorganic layer is less than the sum of the depth of the etched cavity and the thickness of the first inorganic layer; the first inorganic filling part does not completely fill the etched via hole and forms a pit;
[0023] The second conductive layer further includes a second inorganic filling portion; the second filling portion is located in the pit.
[0024] In the ultrasonic transducer provided by the present disclosure, the orthographic projection of the second conductive layer on the driving backplate does not overlap with the orthographic projection of the etched via on the driving backplate.
[0025] The ultrasonic transducer provided in the present disclosure further includes:
[0026] The fourth inorganic layer is located on a side of the second conductive layer away from the third inorganic layer and covers the second conductive layer.
[0027] In the ultrasonic transducer provided by the present disclosure, the third inorganic layer is located on a side of the second conductive layer facing away from the first inorganic layer, and covers the second conductive layer.
[0028] In the ultrasonic transducer provided in the present disclosure, the second conductive layer also includes a second inorganic filling portion; the second inorganic filling portion is located in the etching cavity; the first inorganic filling portion is located on the side of the second inorganic filling portion away from the driving backplate; the thickness of the third inorganic layer is greater than or equal to the difference between the depth of the vibration cavity and the thickness of the second conductive layer.
[0029] In the ultrasonic transducer provided by the present disclosure, the orthographic projection of the second conductive layer on the driving backplate does not overlap with the orthographic projection of the etched via on the driving backplate; and the thickness of the third inorganic layer is greater than or equal to the depth of the etched cavity.
[0030] The ultrasonic transducer provided in the present disclosure further includes:
[0031] a second flat layer, located on a side of the third inorganic layer facing away from the driving back plate;
[0032] The height of the third inorganic layer in the region overlapping with the vibration cavity is greater than the height of other regions of the third inorganic layer;
[0033] The height of the second flat layer is less than or equal to the height of the third inorganic layer in the region overlapping with the vibration cavity, so as to expose the surface of the third inorganic layer in the region overlapping with the vibration cavity.
[0034] The ultrasonic transducer provided in the present disclosure further includes:
[0035] The buffer layer is located between the first conductive layer and the first inorganic layer; the vibration cavity and the etching cavity are located between the first inorganic layer and the buffer layer.
[0036] According to a second aspect of the present disclosure, a display panel is provided, comprising any one of the above-mentioned ultrasonic transducers.
[0037] According to a third aspect of the present disclosure, a display device is provided, comprising any one of the display panels described above.
[0038] A fourth aspect of the present disclosure provides a method for manufacturing an ultrasonic transducer, comprising:
[0039] A first conductive layer is formed on one side of the driving backplane; the first conductive layer includes a first electrode, and the first electrode is electrically connected to the driving backplane;
[0040] A sacrificial layer is formed on the side of the first conductive layer away from the driving back plate, and the sacrificial layer is etched to form a vibration cavity pattern and an etched cavity pattern; the etched cavity pattern is connected to the vibration cavity pattern;
[0041] A first inorganic layer is formed on a side of the sacrificial layer away from the first conductive layer, and the first inorganic layer is etched to form an etched via hole penetrating the first inorganic layer in a direction perpendicular to the driving backplane; the etched via hole is etched to expose an etched cavity pattern;
[0042] The sacrificial layer is wet-etched, and the etching liquid is allowed to etch the etching cavity pattern and the vibration cavity pattern in sequence through the etching via hole to form the vibration cavity and the etching cavity;
[0043] A second conductive layer is formed on the side of the first inorganic layer facing away from the driving backplane; the second conductive layer includes a second electrode;
[0044] A first inorganic filling part is manufactured by a thin film deposition process; the first inorganic filling part is located in the etching cavity and the etching via hole to block the etching via hole.
[0045] The beneficial effects of the present disclosure are as follows:
[0046] The present disclosure provides an ultrasonic transducer and a manufacturing method thereof, a display panel, and a display device. The ultrasonic transducer includes: a driving backplane, a first conductive layer, a first inorganic layer, a second conductive layer, and a first inorganic filling portion. The first conductive layer is located on the driving backplane. The first conductive layer includes a first electrode, which is electrically connected to the driving backplane. The first inorganic layer is located on the side of the first conductive layer facing away from the driving backplane. A vibration cavity and an etching cavity are provided between the first inorganic layer and the first conductive layer. The first inorganic layer has an etching via that penetrates the first inorganic layer in a direction perpendicular to the driving backplane. The etching cavity is respectively connected to the vibration cavity and the etching via to form an etching channel. The second conductive layer is located on the side of the first inorganic layer facing away from the driving backplane. The second conductive layer includes a second electrode. The first inorganic filling portion is located in the etching cavity and the etching via to block the etching via; the material of the inorganic filling portion is an inorganic material. During the manufacturing process of the ultrasonic transducer provided by the embodiment of the present disclosure, after the vibration cavity and the etching cavity are formed by wet etching the sacrificial layer, the etched vias are encapsulated through a thin film deposition process. After the inorganic material adheres to the surface of the substrate, it no longer flows. The film formation process has good directionality, which can prevent the inorganic material from diffusing into the vibration cavity along the extension direction of the etching cavity and causing blockage of the vibration cavity. Organic materials have a certain degree of fluidity. When organic materials are used to encapsulate the etched vias, the organic material flows into the vibration cavity along the extension direction of the etching cavity and easily causes blockage of the vibration cavity. Compared with encapsulating the etched vias with organic materials, encapsulating the etched vias with inorganic materials can greatly improve the product yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments of the present disclosure. Obviously, the drawings introduced below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0048] FIG1a is a schematic diagram of a top view of the structure of an ultrasonic transducer provided in an embodiment of the present disclosure;
[0049] FIG1b is a schematic diagram of a cross-sectional structure of an ultrasonic transducer provided in an embodiment of the present disclosure;
[0050] FIG1c is a second schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0051] FIG1d is a third schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0052] Figure 2a is a microstructure diagram of an organic material encapsulated etched via;
[0053] Figure 2b is a microstructure diagram of an inorganic material encapsulated etched via;
[0054] FIG3a is a fourth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0055] FIG3 b is a fifth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0056] FIG4a is a sixth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0057] FIG4 b is a seventh schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0058] FIG4c is an eighth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0059] FIG4 d is a ninth schematic diagram of a cross-sectional structure of an ultrasonic transducer provided in an embodiment of the present disclosure;
[0060] FIG4e is a tenth schematic diagram of the cross-sectional structure of an ultrasonic transducer provided in an embodiment of the present disclosure;
[0061] FIG4 f is an eleventh schematic diagram of a cross-sectional structure of an ultrasonic transducer provided in an embodiment of the present disclosure;
[0062] FIG4g is a twelfth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure;
[0063] FIG4h is a thirteenth schematic diagram of a cross-sectional structure of an ultrasonic transducer provided in an embodiment of the present disclosure;
[0064] FIG5 is a schematic diagram of a cross-sectional structure of a display panel provided in an embodiment of the present disclosure;
[0065] FIG6 is a flow chart of a method for manufacturing an ultrasonic transducer provided in an embodiment of the present disclosure. DETAILED DESCRIPTION
[0066] In order to make the above-mentioned purposes, features and advantages of the present disclosure more obvious and easy to understand, the present disclosure will be further described below with reference to the accompanying drawings and examples. However, the example embodiments can be implemented in various forms and should not be understood as being limited to the embodiments set forth herein; on the contrary, these embodiments are provided to make the present disclosure more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and their repeated descriptions will be omitted. The words expressing position and direction described in the present disclosure are all explained using the accompanying drawings as examples, but changes can be made as needed, and all changes are included in the scope of protection of the present disclosure. The drawings of the present disclosure are only used to illustrate relative position relationships and do not represent true proportions.
[0067] Fingerprint recognition technology is widely used in mobile devices such as mobile phones and tablets, as well as in security systems such as access control systems and safes. Currently, fingerprint acquisition is primarily accomplished through optical, capacitive, and ultrasonic imaging methods. Ultrasonic fingerprint recognition technology, in particular, features 3D fingerprint acquisition and eliminates the need for the user's finger to touch the fingerprint acquisition device, improving recognition security and user experience.
[0068] Ultrasonic fingerprint recognition technology often uses piezoelectric micromachined ultrasonic transducers (PMUTs) or capacitive micromachined ultrasonic transducers (CMUTs) as ultrasonic transmitters and receivers. Compared to traditional PMUTs, CMUTs offer greater signal bandwidth and penetration, and have garnered significant attention in the field of ultrasonic imaging. However, CMUTs currently suffer from difficulties in cavity fabrication and low yield rates.
[0069] In view of this, a first aspect of an embodiment of the present disclosure provides an ultrasonic transducer for improving product yield.
[0070] Figure 1a is a schematic diagram of the top view of the ultrasonic transducer provided in an embodiment of the present disclosure; Figure 1b is one of the schematic diagrams of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure; Figure 1c is a second schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure; and Figure 1d is a third schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure.
[0071] In the disclosed embodiment, as shown in Figures 1a to 1d, where Figure 1a is a schematic top view of a local area of the ultrasonic transducer, Figure 1b is a schematic cross-sectional view taken along section line AA in Figure 1a, Figure 1c is a schematic cross-sectional view taken along section line BB in Figure 1a, and Figure 1d is a schematic cross-sectional view taken along section line CC in Figure 1a, the ultrasonic transducer includes a driving backplate 100, a first conductive layer 210, a first inorganic layer 230, a second conductive layer 240, and a first inorganic filler 250.
[0072] The driver backplane 100 is located at the bottom of the ultrasonic transducer. The driver backplane 100 includes a drive circuit composed of multiple thin film transistors (TFTs), capacitors, and resistors. In practice, the driver backplane can be manufactured using a glass-based process. Taking a low-temperature polysilicon (LTPS) TFT driver backplane as an example, its manufacturing process mainly includes the following steps:
[0073] 1. Fabricate a flexible layer 120 and a barrier layer 130 on a glass substrate 110 to form a flexible substrate. Specifically, the flexible layer 120 and barrier layer 130 can be a single-layer structure or a multi-layer structure. When a multi-layer structure is used, multiple flexible layers 120 and multiple barrier layers 130 can be alternately arranged, without limitation. The flexible layer 120 can be made of polyimide (PI), and the barrier layer 130 can be made of an inorganic material such as silicon oxide, silicon nitride, or silicon oxynitride, without limitation.
[0074] 2. Depositing low-temperature polysilicon on the surface of a flexible substrate fabricated on a glass substrate 110 and etching it to form an active layer for forming a TFT conductive channel;
[0075] 3. A gate insulating layer (GI) is formed on the side of the active layer facing away from the glass substrate 110. The gate insulating layer can be made of insulating materials such as silicon oxide, silicon nitride, and silicon oxynitride, which are not limited here.
[0076] 4. A gate metal layer is formed on the side of the gate insulating layer facing away from the active layer. The gate metal layer includes the gate electrode of the TFT. The gate metal layer may also include the lower electrode of the capacitor, which is not limited here. The material of the gate metal layer can be a conductive material such as metal, which is not limited here.
[0077] 5. A first interlayer insulating layer (ILD) 140 is formed on the side of the gate metal layer facing away from the gate insulating layer. After exposure through a mask, the first interlayer insulating layer 140 and the gate insulating layer are etched to form a first opening that penetrates both the first interlayer insulating layer 140 and the gate insulating layer. The first opening exposes the source region and the drain region of the active layer. The material of the first interlayer insulating layer 140 can be an insulating material such as silicon oxide, silicon nitride, or silicon oxynitride, which is not limited here;
[0078] 6. A first source-drain metal layer (SD1) is formed on the side of the first interlayer insulating layer 140 facing away from the gate metal layer. The first source-drain metal layer includes the source and drain electrodes of the TFT. The source and drain electrodes of the TFT are filled in the first opening formed by the first interlayer insulating layer 140 and the gate insulating layer, and are electrically connected to the source region and drain region of the active layer, respectively. The first source-drain metal layer may also include the upper electrode of the capacitor, wiring for connecting each TFT, and wiring with other functions, which are not limited here. The material of the first source-drain metal layer can be a conductive material such as metal, which is not limited here;
[0079] 7. Form a second interlayer insulating layer on the side of the first source / drain metal layer facing away from the first interlayer insulating layer 140, and etch the second interlayer insulating layer to form a second opening (not shown) for exposing a portion of the source or drain of the TFT. The material of the second interlayer insulating layer can be insulating materials such as silicon oxide, silicon nitride, and silicon oxynitride, which are not limited here;
[0080] 8. Form a second source / drain metal layer on a side of the second interlayer insulating layer facing away from the first source / drain metal layer. The second source / drain metal layer at least partially fills the second opening and is electrically connected to the source or drain electrode exposed by the second opening, thereby leading the source or drain electrode to the surface of the second interlayer insulating layer to facilitate subsequent connection (not shown in the figure). The second source / drain metal layer may also include wiring with other functions, which are not limited here;
[0081] 9. Form a third planar layer (PLN) 150 on the side of the second source / drain metal layer facing away from the second interlayer insulating layer. The third planar layer 150 can be made of an organic material such as resin and needs to be aged in a heating furnace to solidify the organic material. The third planar layer 150 is formed by etching to form a third opening (not shown in the figure) that exposes the second source / drain metal layer.
[0082] 10. A passivation layer (PVX) 160 is formed on the side of the third planar layer 150 facing away from the second source / drain metal layer. A fourth opening (not shown) is formed through the passivation layer 160 by etching. The orthographic projection of the fourth opening on the glass substrate 110 coincides with the orthographic projection of the third opening on the glass substrate 110, thereby connecting the fourth opening to the third opening and facilitating subsequent electrical connection between the first electrode and the driving backplane 100.
[0083] The above process is illustrated by the manufacturing process of a top-gate LTPS TFT driver backplane. In some embodiments, the TFT in the driver backplane 100 may also be a bottom-gate or dual-gate structure, which is not limited here. In some embodiments, the driver backplane 100 may also be an oxide TFT driver backplane or an LTPO driver backplane, etc., which is not limited here. During specific implementation, it can be manufactured according to the specific structure of the driver backplane, with reference to the manufacturing method of the driver backplane in the related art, which is not described in detail here. In some embodiments, after the driver backplane 100 is manufactured or after the ultrasonic transducer is manufactured, the glass substrate 110 can also be removed and the flexible substrate can be retained to realize a flexible device, which is not limited here.
[0084] The first conductive layer 210 is located on the driving backplane 100. Specifically, the first conductive layer 210 is located on the side of the passivation layer 160 away from the third flat layer 150. The first conductive layer 210 includes a first electrode 211, and the first electrode 211 is electrically connected to the driving backplane 100 through the fourth opening and the third opening. The first conductive layer 210 can be made of a metal conductive material or a non-metallic conductive material, which is not limited here. Taking Mo as an example, the thickness of the first conductive layer is generally set to Specifically, it can be set to No limitation is given here.
[0085] The first inorganic layer 230 is located on the side of the first conductive layer 210 away from the driving backplane 100. A vibration cavity M and an etching cavity A are provided between the first inorganic layer 230 and the first conductive layer 210. The first inorganic layer 230 has an etching via H that penetrates the first inorganic layer 230 in a direction perpendicular to the driving backplane 100. The first inorganic layer 230 mentioned in the embodiment of the present disclosure has an etching via H that penetrates the first inorganic layer 230 in a direction perpendicular to the driving backplane 100. Specifically, the etching via H can be completely perpendicular to the driving backplane 100, or the etching via H forms an acute angle of a certain size with the direction perpendicular to the driving backplane 100. The size of the acute angle is not limited here. Among them, the etching cavity A is respectively connected to the vibration cavity M and the etching via H to form an etching channel. In specific implementation, the first inorganic layer 230 can be a single-layer or multi-layer structure made of low-temperature polysilicon, silicon nitride (SiN) or silicon oxide (SiO2), which is not limited here. Taking SiN as an example, the thickness of the first inorganic layer 230 can be set to Specifically, it can be set to No limitation is given here.
[0086] The second conductive layer 240 is located on the side of the first inorganic layer 230 facing away from the driving backplane 100. The second conductive layer 240 includes a second electrode 241. The second conductive layer 240 can be made of a metallic conductive material or a non-metallic conductive material, which is not limited herein.
[0087] The first inorganic filler 250 is located within the etched cavity A and the etched via H to block the etched via H, preventing water and oxygen from entering the ultrasonic transducer through the etched via H and thereby increasing the service life of the ultrasonic transducer. In practice, the first inorganic filler 250 can be fabricated using an inorganic material such as silicon nitride, silicon oxide, or silicon oxynitride, using a thin film deposition process.
[0088] Among them, a resonant cavity M corresponds to a first electrode 211 and a second electrode 241, and a resonant cavity M is located between the corresponding first electrode 211 and the corresponding second electrode 241, forming a transducer unit. An ultrasonic transducer can include at least one transducer unit, which is not limited here. In the transmitting phase, the driving backplate 100 applies a DC signal and an AC signal to the first electrode 211 and the second electrode 241 at the same time, so that the first inorganic layer 230 above the resonant cavity M vibrates and emits ultrasonic waves as the electric field changes; in the receiving phase, only a DC signal is applied to the first electrode 211 and the second electrode 241 to keep the first inorganic layer 230 balanced and receive ultrasonic waves. As shown in Figure 1a, the orthographic projection of the second electrode 241 on the driving backplate 100 can be set to be located within the orthographic projection of the corresponding resonant cavity M on the driving backplate 100, and the orthographic projection of the resonant cavity M on the driving backplate 100 is located within the orthographic projection of the corresponding first electrode 211 on the driving backplate 100, so as to improve the sensitivity of the ultrasonic transducer unit. In a specific implementation, the area of the orthographic projection of the second electrode 241 on the driving backplate 100 can be set to 0.5 times to 0.7 times the area of the orthographic projection of the corresponding vibration cavity M on the driving backplate 100, and the spacing between the edge of the orthographic projection of the vibration cavity M on the driving backplate 100 and the edge of the orthographic projection of the corresponding first electrode 211 on the driving backplate 100 is 1.5μm to 2.5μm, which can obtain better sensitivity. Specifically, the area of the orthographic projection of the second electrode 241 on the driving backplate 100 can be set to 0.6 times the area of the orthographic projection of the corresponding vibration cavity M on the driving backplate 100, and the spacing between the edge of the orthographic projection of the vibration cavity M on the driving backplate 100 and the edge of the orthographic projection of the corresponding first electrode 211 on the driving backplate 100 is 2μm, which is not limited here.
[0089] In the embodiment of the present disclosure, the ultrasonic transducer unit may specifically be a CMUT, which is not limited here.
[0090] In specific implementation, the above structure of the ultrasonic transducer provided by the embodiment of the present disclosure may include the following steps when it is manufactured:
[0091] 1. Form a first conductive layer 210 on the driving backplane 100, and then form a buffer layer 220 on a side of the first conductive layer 210 away from the driving backplane 100 to provide insulation protection for the first conductive layer 210;
[0092] 2. A sacrificial layer S is formed on the side of the buffer layer 220 away from the first conductive layer 210. In a specific implementation, the sacrificial layer S can be made of metal materials such as Mo, Cu, and Al and deposited on the surface of the buffer layer 220. Then, the sacrificial layer S is etched by an etching process to form a vibration cavity pattern and an etching cavity pattern. The etching cavity pattern is connected to the vibration cavity pattern, and the etching cavity pattern and the vibration cavity pattern can form an etching cavity A and a vibration cavity M. Taking Mo as the material of the sacrificial layer S, the thickness of the sacrificial layer S can be generally 2000 nm. Specifically, the thickness of the sacrificial layer S can be Therefore, the depth of the etched cavity A and the vibration cavity M obtained after etching the sacrificial layer S is
[0093] 3. On the side of the sacrificial layer S away from the buffer layer 220, a first inorganic layer 230 is formed, and an etching hole H is formed by etching in a direction perpendicular to the driving backplane 100 to penetrate the first inorganic layer 230 and expose the etching cavity pattern.
[0094] 4. Etching the sacrificial layer S by wet etching. The etching liquid flows into the etching via H and first contacts the etching cavity pattern and etches the etching cavity pattern. After etching the etching cavity pattern, the etching liquid further contacts the vibration cavity pattern and begins to etch the vibration cavity pattern until the sacrificial layer S between the first inorganic layer 230 and the buffer layer 220 is completely etched away, forming the vibration cavity M and the etching cavity A.
[0095] 5. Form a second conductive layer 240 on the side of the first inorganic layer 230 away from the driving backplane 100 , and etch the second conductive layer 240 to form a second electrode 241 ;
[0096] 6. Depositing a first inorganic filling part 250 in the etching cavity A and the etching via hole H by a thin film deposition process, so that the first inorganic filling part 250 fills the etching via hole H to block the etching via hole H.
[0097] FIG2a is a microscopic structure diagram of an organic material package etched via hole; FIG2b is a microscopic structure diagram of an inorganic material package etched via hole.
[0098] During the manufacturing process of the ultrasonic transducer provided by the embodiment of the present disclosure, after the vibration cavity M and the etching cavity A are formed by wet etching the sacrificial layer S, the etched via H is encapsulated by a thin film deposition process. After the inorganic material adheres to the surface of the substrate, it no longer flows. The film formation process has good directionality, which can prevent the inorganic material from diffusing into the vibration cavity M along the extension direction of the etching cavity A and causing blockage of the vibration cavity M. In some technical routes, organic materials are used to directly fill the etching cavity M and the etched via H. Organic materials have a certain degree of fluidity. When the organic material is used to encapsulate the etched via H, the organic material flows into the vibration cavity M along the extension direction of the etching cavity A, which can easily cause blockage of the vibration cavity M, resulting in defective products. Compared with encapsulating the etched via H with an inorganic material, encapsulating the etched via H with an inorganic material can greatly improve the product yield. As shown in Figure 2a, when the etched vias are encapsulated with organic materials, the organic material 10 flows along the extension direction of the etched cavity A to completely fill the etched cavity A, and the risk of blocking the vibration cavity is relatively high; as shown in Figure 2b, when the etched via H is encapsulated with inorganic materials, the inorganic material 20 (the second conductive layer is deposited in the etched cavity A as an example in the figure) is only deposited at the position directly below the etched via H and in the local area adjacent to the etched via H, and will not diffuse to a large extent along the extension direction of the etched cavity A to block the vibration cavity.
[0099] In addition, as shown in FIG1d, in the ultrasonic transducer provided by the embodiment of the present disclosure, the etched via H is directly made on the first inorganic layer 230. When the etched via H is packaged, the etched via H and the etched cavity A directly below the etched via H are completely filled in the direction perpendicular to the driving backplane 100. The thickness h of the package film layer to be deposited is only the sum of the depth of the etched cavity A and the thickness of the film layer of the first inorganic layer 230. The depth of the etched cavity A is taken as The thickness of the first inorganic layer 230 is For example, to completely fill the etched via H and the etched cavity A directly below the etched via H, only the deposition The thickness of the film layer is small, and the thickness of the required packaging film layer is small, which is conducive to reducing the difficulty of manufacturing the packaging film layer.
[0100] As shown in Figure 1a, the second electrodes 241 of multiple transducer units of the ultrasonic transducer are connected through a connecting wire 242 set on the same layer as the second electrode 241. The sacrificial layer S is made of Mo. Mo has good etching performance, which makes it easy to adjust the inclination angle of the side wall of the etching cavity pattern and the side wall of the vibration cavity pattern so that the film layer formed on the side of the etching cavity pattern and the vibration cavity pattern away from the driving backplane 100 has a smoother transition at the corner of the film layer, which is beneficial to avoid the connection wire 242 from being broken at the corner of the film layer, thereby improving the product yield.
[0101] FIG3a is a fourth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure; FIG3b is a fifth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in an embodiment of the present disclosure.
[0102] In some embodiments, as shown in Figures 3a and 3b, where Figure 3a is a schematic cross-sectional structural diagram of Figure 1a along section line BB, and Figure 3b is a schematic cross-sectional structural diagram of Figure 1a along section line CC, the thickness of the second conductive layer 240 is greater than or equal to the depth of the etching cavity A, and the first inorganic filling part 250 is located in the second conductive layer 240. In a specific implementation, when forming the second conductive layer 240, an inorganic conductive material such as a metal can be deposited on a side of the first inorganic layer 230 facing away from the driving backplate 100 through a thin film deposition process. During the deposition process, a portion of the inorganic conductive material is formed within the etching cavity A through the etching via H. When the thickness of the second conductive layer 240 is equal to the depth of the etching cavity A, the inorganic conductive material deposited in the etching cavity A can just block the etched via H, and some of the inorganic conductive material adheres to the sidewalls of the etched via H. The inorganic conductive material adhered to the sidewalls of the etched via H and the inorganic conductive material deposited in the etching cavity A form a continuous, uninterrupted film layer, forming the first inorganic filling part 250, completing the initial packaging of the etched via. When the thickness of the second conductive layer 240 is greater than the depth of the etching cavity A, more inorganic conductive material can be deposited in the etched via H, improving the packaging performance. After the inorganic conductive material of the second conductive layer 240 is deposited, the second conductive layer 240 is etched to form the second electrode 241 and the first inorganic filling part 250, which are spaced apart from each other.
[0103] As shown in Figures 3a and 3b, the ultrasonic transducer also includes a first flat layer 260 and a second inorganic layer 270. The first flat layer 260 is located on the side of the second conductive layer 240 away from the driving backplate 100, which can further improve the packaging performance of the etched via H. The first flat layer 260 is also used to form a relatively flat surface, which is convenient for the production of subsequent film layers, and the relatively flat surface is conducive to improving the directionality of transmitting ultrasonic waves and the sensitivity of receiving ultrasonic waves. The second inorganic layer 270 is located on the side of the first flat layer 260 away from the driving backplate 100. The second inorganic layer 270 covers the first flat layer 260 and the second conductive layer 240, playing a further protective role. In specific implementation, the orthographic projection of the first flat layer 260 on the driving backplate 100 does not overlap with the orthographic projection of the vibration cavity M on the driving backplate 100, which can prevent the first flat layer 260 from increasing the thickness of the diaphragm (including the first inorganic layer 230 and the second inorganic layer 270) located above the vibration cavity M. The collapse voltage calculation formula of the diaphragm is as follows:
[0104] Among them, V col is the collapse voltage, t m is the thickness of the diaphragm, tg is the depth of the vibration cavity, a is the radius of the vibration cavity, Y0 is the Young's modulus of the vibration membrane, ε0 is the dielectric constant of the vibration membrane, T is the residual stress of the vibration membrane, and σ is the Poisson's ratio of the vibration membrane. According to the calculation formula of the collapse voltage of the vibration membrane, the collapse voltage of the vibration membrane V col The size of is related to the thickness of the diaphragm, the thickness of the diaphragm t m The lower the collapse voltage V col The lower the voltage, the more likely it is that the diaphragm will be adsorbed to the bottom of the cavity and collapse. m The lower the collapse voltage V col The lower it is, the lower the required driving voltage is, which is beneficial to reducing the energy consumption of the ultrasonic transducer.
[0105] In some embodiments, as shown in FIG3a , the height of the first inorganic layer 230 in the region overlapping the resonant cavity M is greater than the height of the other regions of the first inorganic layer 230. The height difference h1 between the first inorganic layer 230 in the region overlapping the resonant cavity M and the other regions of the first inorganic layer 230 is approximately the thickness of the first electrode 211. In specific implementations, the height of the first planarizing layer 260 is less than or equal to the height of the first inorganic layer 230 in the region overlapping the resonant cavity M, exposing the surface of the first inorganic layer 230 in the region overlapping the resonant cavity M. This prevents the first planarizing layer 260 from increasing the thickness of the diaphragm by covering this surface. The first planarizing layer 260 can be made of an organic material such as resin by coating, inkjet printing, or other methods. The second inorganic layer 270 can be made of an inorganic material such as silicon nitride, silicon oxynitride, or silicon oxide by thin film deposition, without limitation. The second inorganic layer 270 covers the first electrode 241 not covered by the first planarizing layer 260 to protect it.
[0106] In specific implementation, when the depth of the vibration cavity M is set to When the thickness of the second conductive layer 240 needs to be set to be greater than or equal to So that the first inorganic filling part 250 in the second conductive layer 240 at least just blocks the etching hole H. In a specific implementation, the thickness of the second conductive layer 240 can be set to When the thickness of the first inorganic layer 230 is When the thickness of the second inorganic layer 270 can be set to To ensure that the second inorganic layer 270 completely covers the portion of the second conductive layer 240 that is not covered by the first flat layer 260 (such as the first electrode 241), and at the same time ensure that the thickness of the diaphragm formed by the first inorganic layer 230 and the second inorganic layer 270 is less than This is helpful to reduce power consumption and improve the sensitivity of the ultrasonic transducer.
[0107] In the embodiment shown in Figures 3a and 3b, the second conductive layer 240 is directly used to block the etched vias, and the packaging performance of the etched vias is increased by the first flat layer 260. Then, on the side of the first flat layer 260 away from the driving backplane 100, the second inorganic layer 270 is used to cover the portion of the second conductive layer 240 not covered by the first flat layer 260. The thickness of the diaphragm is only the sum of the thickness of the first inorganic layer 230 and the thickness of the second inorganic layer 270. This can effectively control the thickness of the diaphragm and reduce the power consumption of the ultrasonic transducer.
[0108] Figure 4a is the sixth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure; Figure 4b is the seventh schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure; Figure 4c is the eighth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure; Figure 4d is the ninth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure; Figure 4e is the tenth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure; Figure 4f is the eleventh schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure; Figure 4g is the twelfth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure, and Figure 4h is the thirteenth schematic diagram of the cross-sectional structure of the ultrasonic transducer provided in the embodiment of the present disclosure.
[0109] In some embodiments, as shown in FIG4a-FIG4h, where FIG4a, FIG4c, FIG4e and FIG4g are schematic cross-sectional views of FIG1a along section line BB, and FIG4b, FIG4d, FIG4f and FIG4h are schematic cross-sectional views of FIG1a along section line CC, the thickness of the second conductive layer 240 is less than the depth of the vibration cavity M. Specifically, the depth of the vibration cavity M can be set to The thickness of the second conductive layer 240 can be set to The thickness of the second conductive layer 240 is insufficient to meet the requirement for blocking the etched via H. The ultrasonic transducer further includes a third inorganic layer 280. The third inorganic layer 280 is located on the side of the first inorganic layer 230 facing away from the driving backplate 100. The first inorganic filler 250 is located in the third inorganic layer 280. The third inorganic layer 280 can be made of an inorganic material such as silicon nitride, silicon oxynitride, or silicon oxide, without limitation herein.
[0110] In some embodiments, as shown in Figures 4a-4d, a third inorganic layer 280 is positioned between the second conductive layer 240 and the first inorganic layer 230. The third inorganic layer 280 can be formed through a thin film deposition process after etching the etched cavity pattern and the vibration cavity pattern in the sacrificial layer S and before forming the second conductive layer 240. In a specific implementation, the thickness of the third inorganic layer 280 is greater than or equal to the depth of the etched cavity A, so that the first inorganic filler 250 can at least just block the etched via H. When the thickness of the third inorganic layer 280 is equal to the depth of the etched cavity A, the inorganic material deposited in the etched cavity A can just block the etched via H, and some of the inorganic material adheres to the sidewalls of the etched via H. The inorganic material adhered to the sidewalls of the etched via H forms a continuous, uninterrupted film layer with the inorganic material deposited in the etched cavity A, forming the first inorganic filler 250, completing the initial encapsulation of the etched via. When the thickness of the third inorganic layer 280 is greater than the depth of the etched cavity A, more inorganic material can be deposited in the etched via H, thereby improving packaging performance. After the inorganic material of the third inorganic layer 280 is deposited, the third inorganic layer 280 covers the first inorganic layer 230 and fills the etched cavity A and the etched via H.
[0111] In some embodiments, as shown in Figures 4a and 4b, the thickness of the third inorganic layer 280 is less than the sum of the depth of the etching cavity A and the thickness of the first inorganic layer 230. The first inorganic filling part 250 does not completely fill the etched via H, forming a pit. The second conductive layer 240 also includes a second inorganic filling part 290. The second filling part 290 is located in the pit to further improve the packaging performance of the etched via H. In a specific implementation, after forming the third inorganic layer 280 covering the first inorganic layer 230 and filling the etching cavity A and the etched via H, a second conductive layer 240 can be formed on the side of the third inorganic layer 280 facing away from the driving backplane 100 through a thin film deposition process. The second conductive layer 240 is then etched to form the first electrodes 241 arranged at intervals and the second inorganic filling part 290 located in the pit formed by the etched via H, which is not limited here.
[0112] In some embodiments, as shown in Figures 4c and 4d, the orthographic projection of the second conductive layer 240 on the driving backplate 100 does not overlap with the orthographic projection of the etched via H on the driving backplate 100. In a specific implementation, after forming the third inorganic layer 280 covering the first inorganic layer 230 and filling the etched cavity A and the etched via H, a second conductive layer 240 can be formed on the side of the third inorganic layer 280 facing away from the driving backplate 100 through a thin film deposition process. The second conductive layer 240 is then etched to form the first electrode 241, and the second conductive layer 240 in the area overlapping the etched via H is removed so that the orthographic projection of the second conductive layer 240 on the driving backplate 100 does not overlap with the orthographic projection of the etched via H on the driving backplate 100. This can reduce the area of the second conductive layer 240, avoid parasitic capacitance between the second conductive layer 240 and the first conductive layer 210 in unnecessary areas, or between the second conductive layer 240 and other conductive structures, and reduce the risk of signal crosstalk.
[0113] In some embodiments, as shown in Figures 4a to 4d, the ultrasonic transducer further includes a fourth inorganic layer 300. The fourth inorganic layer 300 is located on the side of the second conductive layer 240 away from the third inorganic layer 280, and the fourth inorganic layer 300 covers the second conductive layer 240 and the third inorganic layer 280 to further play a role of packaging and protection. The material of the fourth inorganic layer 300 can be inorganic materials such as silicon nitride, silicon oxynitride, and silicon oxide, which are not limited here. In a specific implementation, the diaphragm of the ultrasonic transducer includes a first inorganic layer 230, a third inorganic layer 280, and a fourth inorganic layer 300 located above the vibration cavity M, wherein the thickness of the first inorganic layer 230 can be set to Specifically, it can be set to The thickness of the third inorganic layer 280 may be set to Specifically, it can be set to The thickness of the fourth inorganic layer can be set to Specifically, it can be set to The thicker the fourth inorganic layer 300 is, the better the protection effect on the second conductive layer 240 can be. The total thickness of the first inorganic layer 230, the third inorganic layer 280 and the fourth inorganic layer 300 is less than or equal to This can avoid the increase in power consumption of the ultrasonic transducer due to excessive thickness of the diaphragm and ensure the sensitivity of the ultrasonic transducer. In the embodiments shown in Figures 4c and 4d, compared with the embodiments shown in Figures 4a and 4b, the conductive material of the second conductive layer 240 is not used to encapsulate the etched via H. The thicknesses of the first inorganic layer 230, the third inorganic layer 280 and the fourth inorganic layer 300 are respectively and 4c and 4d, the parasitic capacitance of the ultrasonic transducer is approximately 12.5 fc, and the parasitic capacitance of the ultrasonic transducer in the embodiments shown in FIG4a and 4b is approximately 13.9 fc. Reducing the area of the second conductive layer 240 can significantly reduce the parasitic capacitance in the ultrasonic transducer.
[0114] In some embodiments, as shown in Figures 4e-4h, the third inorganic layer 280 is located on the side of the second conductive layer 240 facing away from the first inorganic layer 230. In a specific implementation, the third inorganic layer 280 covers the second conductive layer 240 to protect the second conductive layer 240, thereby reducing the number of packaging film layers provided directly above the vibration cavity M, reducing the thickness of the vibration membrane, and thus reducing the driving voltage and the power consumption of the ultrasonic transducer.
[0115] In some embodiments, as shown in Figures 4e and 4f, the second conductive layer 240 further includes a second inorganic filling portion 290. The second inorganic filling portion 290 is located in the etching cavity A. The first inorganic filling portion 250 is located on the side of the second inorganic filling portion 290 that is away from the driving backplane 100. The thickness of the third inorganic layer 280 is greater than or equal to the difference between the depth of the vibration cavity M and the thickness of the second conductive layer 240, so that the first inorganic filling portion 250 can at least just block the etching via H. In a specific implementation, after completely etching away the etching cavity pattern and the vibration cavity pattern of the sacrificial layer, the second conductive layer 240 can be formed on the side of the first inorganic layer 230 that is away from the driving backplane 100 through a thin film deposition process, wherein a portion of the second conductive layer 240 is deposited in the etching cavity A through the etching via H to form the second inorganic filling portion 290. Because the thickness of the second conductive layer 240 is less than the depth of the etched cavity A, the second inorganic filling part 290 cannot effectively block the etched via H. Therefore, a third inorganic layer 280 is formed on the side of the second conductive layer 240 facing away from the driver backplate 100 through a thin film deposition process. A portion of the third inorganic layer 280 is deposited in the etched cavity A through the etched via H, forming on the side of the second inorganic filling part 290 facing away from the driver backplate 100, thereby forming the first inorganic filling part 250. During fabrication, the thickness of the third inorganic layer 280 is greater than or equal to the difference between the depth of the vibration cavity M and the thickness of the second conductive layer 240. This allows the first inorganic filling part 250 to effectively block the etched via H, thus providing a preliminary encapsulation function. By forming the second inorganic filling part 290 in the etched cavity A, the thickness of the third inorganic layer 280 can be reduced during fabrication of the first inorganic filling part 250, thereby reducing the thickness of the diaphragm, lowering the driving voltage of the ultrasonic transducer, and reducing power consumption.
[0116] In some embodiments, as shown in FIG4g and FIG4h , the orthographic projection of the second conductive layer 240 on the driving backplane 100 does not overlap with the orthographic projection of the etched via H on the driving backplane. The thickness of the third inorganic layer 230 is greater than or equal to the depth of the etched cavity A, so that the second inorganic filling part 290 can be omitted and the etched via H can be directly blocked by the first inorganic filling part 250 formed by the third inorganic layer 280. In specific implementation, after completely etching away the etching cavity pattern and the vibration cavity pattern of the sacrificial layer, a second conductive layer 240 can be formed on the side of the first inorganic layer 230 away from the driving backplane 100 through a thin film deposition process, and the material of the second conductive layer 240 deposited in the etching cavity A is etched away through the etching via H, and then a third inorganic layer 280 is formed on the side of the second conductive layer 240 away from the driving backplane 100 through a thin film deposition process, wherein part of the third inorganic layer 280 is deposited in the etching cavity A through the etching via H and filled in the etching via H to form a first inorganic filling part 250 to block the etching via H.
[0117] In the embodiment shown in FIG. 4e to FIG. 4h , the diaphragm of the ultrasonic transducer includes a first inorganic layer 230 and a third inorganic layer 280 located above the vibration cavity M, wherein the thickness of the first inorganic layer 230 can be set to Specifically, it can be set to The thickness of the third inorganic layer 280 may be set to Specifically, it can be set to The thicker the third inorganic layer 280 is, the better the protection effect on the second conductive layer 240 can be. The total thickness of the first inorganic layer 230 and the third inorganic layer 280 is less than or equal to This is to avoid the increase in power consumption of the ultrasonic transducer due to the excessive thickness of the diaphragm, and to ensure the sensitivity of the ultrasonic transducer. As shown in Figures 4e to 4h, the number of membrane layers arranged directly above the vibration cavity M is relatively small, which is conducive to reducing the thickness of the diaphragm, thereby reducing the driving voltage and reducing the power consumption of the ultrasonic transducer. Among them, in the embodiments shown in Figures 4g and 4h, compared with the embodiments shown in Figures 4e and 4f, the second inorganic filling part 290 is not provided in the etching cavity A. In the embodiments shown in Figures 4g and 4h, the area of the second conductive layer 240 is smaller, and the thicknesses of the first inorganic layer 230 and the third inorganic layer 280 are respectively and 4g and 4h, the parasitic capacitance is approximately 12.5 fc, and the parasitic capacitance in the embodiments shown in FIG. 4e and 4f is approximately 13.9 fc. Reducing the area of the second conductive layer 240 can significantly reduce the parasitic capacitance in the ultrasonic transducer.
[0118] In some embodiments, as shown in Figures 4a-4h, the ultrasonic transducer further includes a second planar layer 310. The second planar layer 310 is located on the side of the third inorganic layer 280 facing away from the driver backplate 100, further improving the packaging performance of the etched via H. The second planar layer 310 also forms a relatively flat surface, facilitating the fabrication of subsequent film layers. This relatively flat surface also helps improve the directionality of transmitted ultrasonic waves and the sensitivity of received ultrasonic waves.
[0119] In a specific implementation, as shown in Figures 4a-4h, the height of the third inorganic layer 280 in the region overlapping with the resonant cavity M is greater than the height of other regions of the third inorganic layer 280. The height of the second flattening layer 310 is less than or equal to the height of the third inorganic layer 280 in the region overlapping with the resonant cavity M, thereby exposing the surface of the third inorganic layer 280 in the region overlapping with the resonant cavity M. This can prevent the second flattening layer 310 from increasing the thickness of the diaphragm located above the resonant cavity M, reduce the driving voltage, and thus reduce the power consumption of the ultrasonic transducer.
[0120] FIG5 is a schematic diagram of the cross-sectional structure of a display panel provided in an embodiment of the present disclosure.
[0121] In a second aspect of the present disclosure, a display panel is further provided, comprising an ultrasonic transducer provided by any of the above embodiments. In specific implementations, the display panel may be a liquid crystal display (LCD) panel, an organic light emitting diode (OLED) display panel, a light emitting diode (LED) display panel, a micro light emitting diode (Micro LED) display panel, etc., without limitation herein. The ultrasonic transducer can be used to implement fingerprint recognition, gesture recognition, touch operation and other functions of the display panel, without limitation herein.
[0122] For example, the display panel provided by the present disclosure may be an OLED display panel. As shown in FIG5 , the OLED display panel may include an ultrasonic transducer 1, a matching layer 2, an OLED display substrate 3, and a protective cover plate 4 stacked in sequence. The matching layer 2 is used for impedance matching between the ultrasonic transducer 1 and the OLED display substrate 3, to improve the efficiency of ultrasonic transmission, and to perform bonding between the ultrasonic transducer 1 and the OLED display substrate 3. In specific implementation, the matching layer 2 may be made of optical adhesive (Optically Clear Adhesive, abbreviated as OCA), which is not limited here. In specific implementation, the OLED display panel may also be of other structures which are not limited here. When the display panel provided by the present disclosure is other types of display panels, the structure is similar to that of the OLED display panel and will not be elaborated here.
[0123] The display panel provided by the embodiment of the present disclosure has the same or similar technical effects as the ultrasonic transducer provided by any of the above embodiments, and will not be described in detail here.
[0124] A third aspect of the present disclosure further provides a display device, comprising the display panel provided in any of the aforementioned embodiments. The display device may be a mobile phone, a tablet computer, a laptop computer, or the like, without limitation herein. The display device provided in the embodiments of the present disclosure has the same or similar technical effects as the display panel provided in any of the aforementioned embodiments, and a detailed description thereof is omitted here.
[0125] FIG6 is a flow chart of a method for manufacturing an ultrasonic transducer provided in an embodiment of the present disclosure.
[0126] A fourth aspect of the present disclosure further provides a method for manufacturing an ultrasonic transducer, as shown in FIG6 , the method comprising the following steps:
[0127] S410: forming a first conductive layer on one side of the driving backplane; the first conductive layer includes a first electrode, and the first electrode is electrically connected to the driving backplane;
[0128] S420: forming a sacrificial layer on a side of the first conductive layer away from the driving back plate, etching the sacrificial layer to form a vibration cavity pattern and an etched cavity pattern; and connecting the etched cavity pattern to the vibration cavity pattern;
[0129] S430: forming a first inorganic layer on a side of the sacrificial layer away from the first conductive layer, etching the first inorganic layer to form an etched via hole penetrating the first inorganic layer in a direction perpendicular to the driving backplane; etching the via hole to expose an etched cavity pattern;
[0130] S440: wet-etching the sacrificial layer so that the etching solution passes through the etching vias to sequentially etch the etching cavity pattern and the vibration cavity pattern to form a vibration cavity and an etching cavity;
[0131] S450: forming a second conductive layer on a side of the first inorganic layer away from the driving backplane; the second conductive layer includes a second electrode;
[0132] S460: forming a first inorganic filling portion through a thin film deposition process; the first inorganic filling portion is located in the etching cavity and the etching via hole to block the etching via hole.
[0133] In the method for manufacturing an ultrasonic transducer provided by the embodiments of the present disclosure, after forming a resonant cavity M and an etching cavity A by wet etching a sacrificial layer S, the etched via H is encapsulated through a thin film deposition process. After the inorganic material adheres to the substrate surface, it no longer flows, and the film formation process has good directionality, which can prevent the inorganic material from diffusing into the resonant cavity M along the extension direction of the etching cavity A and causing blockage of the resonant cavity M. Organic materials have a certain degree of fluidity. When encapsulating the etched via H with an organic material, the organic material can easily flow into the resonant cavity M along the extension direction of the etching cavity A and cause blockage of the resonant cavity M. Using an inorganic material to encapsulate the etched via H can greatly improve product yield compared to using an organic material to encapsulate the etched via H.
[0134] In addition, as shown in FIG1d, in the ultrasonic transducer provided by the embodiment of the present disclosure, the etched via H is directly made on the first inorganic layer 230. When the etched via H is packaged, the etched via H and the etched cavity A directly below the etched via H are completely filled in the direction perpendicular to the driving backplane 100. The thickness of the packaging film layer that needs to be deposited is only the sum of the depth of the etched cavity A and the thickness of the film layer of the first inorganic layer 230. The depth of the etched cavity A is taken as The thickness of the first inorganic layer 230 is For example, to completely fill the etched via H and the etched cavity A directly below the etched via H, only the deposition The thickness of the film layer is small, and the thickness of the required packaging film layer is small, which is conducive to reducing the difficulty of manufacturing the packaging film layer.
[0135] The embodiments of the present disclosure have described the specific structure of the ultrasonic transducer in detail. During specific implementation, the specific manufacturing method of the ultrasonic transducer provided by the embodiments of the present disclosure can refer to the specific structure of the aforementioned ultrasonic transducer and will not be repeated here.
[0136] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present disclosure.
[0137] Obviously, those skilled in the art may make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include these modifications and variations.
Claims
1. An ultrasonic transducer, wherein: include: Driver backplane; A first conductive layer, located on the driving backplane; The first conductive layer includes a first electrode, and the first electrode is electrically connected to the driving backplane; A first inorganic layer is located on a side of the first conductive layer away from the driving backplane; a vibration cavity and an etching cavity are provided between the first inorganic layer and the first conductive layer; The first inorganic layer has an etched via hole penetrating the first inorganic layer in a direction perpendicular to the driving backplane; The etching cavity is respectively connected to the vibration cavity and the etching via hole to form an etching channel; A second conductive layer is located on a side of the first inorganic layer away from the driving backplane; The second conductive layer includes a second electrode; The first inorganic filling part is located in the etching cavity and the etching via hole to block the etching via hole; the material of the first inorganic filling part is an inorganic material.
2. The ultrasonic transducer according to claim 1, wherein: The thickness of the second conductive layer is greater than or equal to the depth of the etching cavity; and the first inorganic filling part is located in the second conductive layer.
3. The ultrasonic transducer according to claim 2, wherein: The ultrasonic transducer also includes: A first flat layer is located on a side of the second conductive layer away from the driving back plate; an orthographic projection of the first flat layer on the driving back plate does not overlap with an orthographic projection of the vibration cavity on the driving back plate; The second inorganic layer is located on a side of the first planar layer away from the driving back plate, and covers the first planar layer and the second conductive layer.
4. The ultrasonic transducer according to claim 3, wherein: The height of the first inorganic layer in the region overlapping with the vibration cavity is greater than the height of other regions of the first inorganic layer; The height of the first flat layer is less than or equal to the height of the first inorganic layer in the region overlapping with the vibration cavity, so as to expose the surface of the first inorganic layer in the region overlapping with the vibration cavity.
5. The ultrasonic transducer according to claim 1, wherein: The thickness of the second conductive layer is smaller than the depth of the vibration cavity; The ultrasonic transducer also includes: The third inorganic layer is located on a side of the first inorganic layer away from the driving back plate; and the first inorganic filling part is located in the third inorganic layer.
6. The ultrasonic transducer according to claim 5, wherein: The third inorganic layer is located between the second conductive layer and the first inorganic layer; and the thickness of the third inorganic layer is greater than or equal to the depth of the etching cavity.
7. The ultrasonic transducer according to claim 6, wherein: The thickness of the third inorganic layer is less than the sum of the depth of the etching cavity and the thickness of the first inorganic layer; the first inorganic filling part does not completely fill the etching via hole and forms a pit; The second conductive layer also includes a second inorganic filling portion; the second filling portion is located in the pit.
8. The ultrasonic transducer according to claim 6, wherein: An orthographic projection of the second conductive layer on the driving backplane does not overlap with an orthographic projection of the etched via on the driving backplane.
9. The ultrasonic transducer according to claim 6, wherein: Also includes: The fourth inorganic layer is located on a side of the second conductive layer away from the third inorganic layer and covers the second conductive layer.
10. The ultrasonic transducer according to claim 5, wherein: The third inorganic layer is located on a side of the second conductive layer away from the first inorganic layer, and covers the second conductive layer.
11. The ultrasonic transducer according to claim 10, wherein: The second conductive layer also includes a second inorganic filling portion; the second inorganic filling portion is located in the etching cavity; the first inorganic filling portion is located on the side of the second inorganic filling portion away from the driving backplane; the thickness of the third inorganic layer is greater than or equal to the difference between the depth of the vibration cavity and the thickness of the second conductive layer.
12. The ultrasonic transducer according to claim 10, wherein: The orthographic projection of the second conductive layer on the driving backplane does not overlap with the orthographic projection of the etched via on the driving backplane; and the thickness of the third inorganic layer is greater than or equal to the depth of the etching cavity.
13. The ultrasonic transducer according to any one of claims 5 to 12, wherein: Also includes: A second flat layer is located on a side of the third inorganic layer away from the driving back plate; The height of the third inorganic layer in the region overlapping with the vibration cavity is greater than the height of other regions of the third inorganic layer; The height of the second flat layer is less than or equal to the height of the third inorganic layer in the region overlapping with the vibration cavity, so as to expose the surface of the third inorganic layer in the region overlapping with the vibration cavity.
14. The ultrasonic transducer according to any one of claims 1 to 12, wherein: Also includes: The buffer layer is located between the first conductive layer and the first inorganic layer; the vibration cavity and the etching cavity are located between the first inorganic layer and the buffer layer.
15. A display panel, wherein: Comprising the ultrasonic transducer according to any one of claims 1 to 14.
16. A display device, wherein: Comprising the display panel as claimed in claim 15.
17. A method for manufacturing an ultrasonic transducer, wherein: include: forming a first conductive layer on one side of the driving backplane; The first conductive layer includes a first electrode, and the first electrode is electrically connected to the driving backplane; A sacrificial layer is formed on a side of the first conductive layer away from the driving back plate, and the sacrificial layer is etched to form a vibration cavity pattern and an etching cavity pattern; the etching cavity pattern is connected to the vibration cavity pattern; Forming a first inorganic layer on a side of the sacrificial layer away from the first conductive layer, and etching the first inorganic layer to form an etched via hole penetrating the first inorganic layer in a direction perpendicular to the driving backplane; The etched via exposes the etched cavity pattern; Wet etching the sacrificial layer so that the etching solution passes through the etching via hole to sequentially etch the etching cavity pattern and the vibration cavity pattern to form a vibration cavity and an etching cavity; A second conductive layer is formed on a side of the first inorganic layer away from the driving backplane; the second conductive layer includes a second electrode; A first inorganic filling part is manufactured by a thin film deposition process; the first inorganic filling part is located in the etching cavity and the etching via hole to block the etching via hole.