Ultrasonic transducer substrate and ultrasonic transducer

Abstract

The exemplary embodiments of the present application disclose an ultrasonic transducer substrate and an ultrasonic transducer, and relate to but are not limited to the technical field of ultrasonic transducers. The ultrasonic transducer substrate forms at least one support column in a cavity between a first electrode layer and a diaphragm structure layer, the support column can provide support for the diaphragm structure layer, and in subsequent processes and use, the movement space of the diaphragm structure layer to the substrate side is reduced, so that the collapse of the diaphragm structure layer can be effectively avoided. Meanwhile, the cavity has a first height, the support column has a second height, the second height is less than the first height, and the first height and the second height are the dimensions in the direction perpendicular to the substrate. In this way, the diaphragm structure layer still has space to vibrate, the arrangement of the support column does not affect the normal work of the diaphragm structure layer, and the vibration performance of the ultrasonic transducer substrate is ensured.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of ultrasonic transducer technology, specifically to an ultrasonic transducer substrate and an ultrasonic transducer. Background Technology

[0002] Ultrasound has the advantages of good directional focus and high energy density during propagation, while not producing noise pollution that affects people's lives and work, nor does it produce electromagnetic pollution like electromagnetic waves. Therefore, ultrasound has a wide range of applications in many industrial fields. Ultrasound can also be used for ultrasonic diagnostics, ultrasonic flaw detection, ultrasonic testing, ultrasonic polishing, ultrasonic stirring, ultrasonic therapy, ultrasonic imaging, and ultrasonic demodulation for audible sound.

[0003] In various ultrasonic applications, ultrasonic sensors are the most crucial components. Among these, capacitive micromechanical ultrasonic transducers (CMUTs) have broad application prospects. CMUTs utilize micromechanical technology and capacitive sensing principles to achieve high-precision, high-sensitivity ultrasonic detection and measurement. The basic structure of a CMUT consists of a parallel-plate capacitor composed of a diaphragm structure layer and electrode pairs. When a DC voltage is applied, the resulting electrostatic force counteracts the tension of the diaphragm structure layer. When an AC voltage is applied to the diaphragm structure layer, the layer resonates, driving the surrounding medium to perform work and generate a large amount of ultrasonic waves. When these ultrasonic waves act on the diaphragm structure layer, they change the capacitance of the capacitor, thereby generating an electrical signal.

[0004] Because there is a cavity inside the CMUT and an inorganic film layer in the diaphragm structure layer, there is a certain stress. Therefore, the diaphragm structure layer is prone to collapse during subsequent processes and use, leading to CMUT failure. Summary of the Invention

[0005] The following is an overview of the subject matter described in detail in this application. This overview is not intended to limit the scope of the claims.

[0006] The technical problem to be solved by the embodiments of this application is to provide an ultrasonic transducer substrate and an ultrasonic transducer, so as to solve the technical problem that the existing structure is prone to diaphragm structure layer collapse during subsequent processing and use, resulting in ultrasonic sensor failure.

[0007] On one hand, embodiments of this application provide an ultrasonic transducer substrate, including a first electrode layer disposed on a substrate, a diaphragm structure layer disposed on the side of the first electrode layer away from the substrate, and a second electrode layer disposed on the side of the diaphragm structure layer away from the substrate. A cavity is disposed between the first electrode layer and the diaphragm structure layer, and at least one support column is disposed in the cavity. The cavity has a first height, and the support column has a second height, the second height being less than the first height. The first height and the second height are dimensions perpendicular to the substrate.

[0008] On the other hand, embodiments of this application also provide an ultrasonic transducer, including the ultrasonic transducer substrate as described above.

[0009] An exemplary embodiment of this application provides an ultrasonic transducer substrate and an ultrasonic transducer. By forming at least one support column in the cavity located between the first electrode layer and the diaphragm structure layer, the support column can provide support for the diaphragm structure layer. In subsequent processes and use, the space for the diaphragm structure layer to move towards the substrate is reduced, which can effectively prevent the diaphragm structure layer from collapsing. At the same time, the cavity has a first height, and the support column has a second height, which is smaller than the first height. The first height and the second height are dimensions perpendicular to the substrate direction. In this way, the diaphragm structure layer still has the ability to vibrate in space. The setting of the support column will not affect the normal operation of the diaphragm structure layer, thus ensuring the vibration performance of the ultrasonic transducer substrate.

[0010] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0011] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0012] Figure 1 This is a schematic diagram of the planar structure of the ultrasonic transducer substrate in the embodiments of this application;

[0013] Figure 2 for Figure 1 Sectional view along the AA direction;

[0014] Figure 3 for Figure 1 Cross-sectional view along the BB direction;

[0015] Figure 4 This is a schematic diagram showing the driver circuit layer after it has been formed according to an embodiment of this application;

[0016] Figure 5 This is a schematic diagram showing the formation of the first conductive layer pattern according to an embodiment of this application;

[0017] Figure 6 This is a schematic diagram of the sacrificial layer pattern formed according to an embodiment of this application, with the cross-sectional position along the AA direction;

[0018] Figure 7 This is a schematic diagram of the sacrificial layer pattern formed according to an embodiment of this application, showing the cross-sectional position along the BB direction;

[0019] Figure 8 This is a schematic diagram of the planar structure for forming the first diaphragm layer pattern according to an embodiment of this application;

[0020] Figure 9 This is a schematic diagram of the first diaphragm layer pattern formed according to an embodiment of this application, with the cross-sectional position along line AA.

[0021] Figure 10 This is a schematic diagram of the first diaphragm layer pattern formed according to an embodiment of this application, with the BB direction showing the cross-sectional position.

[0022] Figure 11 This is a schematic diagram of the cavity pattern formed according to an embodiment of this application, with the cross-sectional position along line AA.

[0023] Figure 12 This is a schematic diagram of the cavity pattern formed according to an embodiment of this application, showing the cross-sectional position along the BB direction;

[0024] Figure 13 This is a schematic diagram of the transition structure formed in the embodiment of this application, with the cross-sectional position along the AA direction;

[0025] Figure 14 This is a schematic diagram of the transition structure formed in the embodiments of this application, showing the cross-sectional position along the BB direction;

[0026] Figure 15 This is a schematic diagram of the support structure formed according to an embodiment of this application, showing the cross-sectional position along direction AA;

[0027] Figure 16 This is a schematic diagram of the support structure formed according to an embodiment of this application, showing the cross-sectional position along the BB direction;

[0028] Figure 17 This is a schematic diagram of the second conductive layer pattern formed according to an embodiment of this application, with the cross-sectional position along line AA.

[0029] Figure 18 This is a schematic diagram of the second conductive layer pattern formed according to an embodiment of this application, with the BB direction showing the cross-sectional position.

[0030] Figure 19 This is a schematic diagram of the second insulating layer after it has been formed according to an embodiment of this application, with the cross-sectional position along line AA.

[0031] Figure 20 for Figure 19A magnified structural diagram of part C in the diagram.

[0032] Explanation of reference numerals in the attached figures:

[0033] M, Ultrasonic transducer unit; 10, Drive circuit layer; 11, First transistor; 12, Second transistor; 13, Capacitor; 21, First electrode; 22, First insulating layer; 23, Sacrificial layer; 231, Sacrificial part; 232, Sacrificial connection part; 24, First diaphragm layer; 25, Support column; 25a, Transition column; 26, Second diaphragm layer; 27, Third diaphragm layer; 28, Second electrode; 29, Second insulating layer; 30, Substrate; 100, First via; 200, Cavity; 201, Cavity part; 202, Cavity connection part; 300, Through hole. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below with reference to the accompanying drawings. Note that the implementation methods can be carried out in many different forms. Those skilled in the art will readily understand that the methods and content can be transformed into various forms without departing from the spirit and scope of this application. Therefore, this application should not be construed as being limited only to the content described in the following embodiments. Unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0035] The scale of the figures in this application can be used as a reference in actual manufacturing processes, but is not limited thereto. For example, the aspect ratio of the channel, the thickness and spacing of each film layer, and the width and spacing of each signal line can be adjusted according to actual needs. The number of pixels in the display substrate and the number of sub-pixels in each pixel are not limited to the quantities shown in the figures. The figures described in this application are only schematic diagrams of the structure, and the embodiments of this application are not limited to the shapes or values ​​shown in the figures.

[0036] The ordinal numbers “first,” “second,” and “third” used in this specification are used to avoid confusion among the constituent elements, not to limit their quantity.

[0037] In this specification, for convenience, terms such as "middle," "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate orientation or positional relationships in conjunction with the accompanying drawings. This is solely for the purpose of facilitating the description and simplification, and does not imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application. The positional relationships of the constituent elements may be appropriately varied depending on the direction in which each constituent element is described. Therefore, the use of terms not limited to those described in the specification may be appropriately replaced as needed.

[0038] In this specification, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection, an indirect connection via an intermediate component, or a connection within two components. Those skilled in the art will understand the specific meaning of these terms in this application based on the specific circumstances.

[0039] In this specification, a transistor is a device that includes at least three terminals: a gate electrode, a drain electrode, and a source electrode. A transistor has a channel region between the drain electrode (drain electrode terminal, drain region, or drain electrode) and the source electrode (source electrode terminal, source region, or source electrode), and current can flow through the drain electrode, the channel region, and the source electrode. Note that in this specification, the channel region refers to the region through which current primarily flows.

[0040] In this specification, the first electrode can be the drain electrode and the second electrode can be the source electrode, or vice versa. In cases where transistors with opposite polarities are used or the current direction changes during circuit operation, the functions of the "source electrode" and "drain electrode" may sometimes be interchanged. Therefore, in this specification, the "source electrode" and "drain electrode" can be interchanged, and the "source terminal" and "drain terminal" can be interchanged.

[0041] In this specification, "electrical connection" includes the situation where components are connected together by elements that have a certain electrical function. There are no particular limitations on what constitutes an "electrical function," as long as it allows for the transmission and reception of electrical signals between the connected components. Examples of "electrical functions" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other elements with various functions.

[0042] In this specification, "parallel" refers to the state where the angle formed by two straight lines is greater than or equal to -10° and less than 10°, and therefore also includes the state where the angle is greater than or equal to -5° and less than 5°. Similarly, "perpendicular" refers to the state where the angle formed by two straight lines is greater than or equal to 80° and less than 100°, and therefore also includes the state where the angle is greater than or equal to 85° and less than 95°.

[0043] In this specification, the terms "film" and "layer" may be interchanged. For example, "conductive layer" may sometimes be replaced with "conductive film." Similarly, "insulating film" may sometimes be replaced with "insulating layer."

[0044] In this specification, triangles, rectangles, trapezoids, pentagons, or hexagons are not strictly defined; they can be approximate triangles, rectangles, trapezoids, pentagons, or hexagons. Small deformations due to tolerances are possible, as are chamfers, curved edges, and other variations.

[0045] In this application, "about" means a value that is not strictly limited and allows for process and measurement errors.

[0046] Figure 1 This is a schematic diagram of the planar structure of the ultrasonic transducer in an embodiment of this application. Figure 1 As shown, the main structure of the ultrasonic transducer in this embodiment may include multiple ultrasonic transducer units M arranged in an array. Each ultrasonic transducer unit M corresponds to a second electrode 28 and multiple first vias 100. The multiple first vias 100 are evenly distributed around the corresponding ultrasonic transducer unit M in the circumferential direction. The sacrificial layer 23 is removed using the first vias 100 to form multiple cavities 200. Each cavity 200 includes a cavity portion 201 and a cavity connecting portion 202, with the cavity connecting portion 202 connecting the cavity portion 201 and the first vias 100. Each ultrasonic transducer unit M corresponds to one of the multiple cavities 200. Adjacent ultrasonic transducer units M share two first vias 100 to reduce the number of first vias 100 and improve fabrication efficiency.

[0047] Figure 2 for Figure 1 Sectional view along the AA direction. Figure 3 for Figure 1 Cross-sectional view along the BB direction. (See attached image.) Figure 2 and Figure 3 As shown, on a plane perpendicular to the substrate 30, the ultrasonic transducer substrate includes a drive circuit layer 10 disposed on the substrate 30, a first electrode 21 layer disposed on the side of the drive circuit layer 10 away from the substrate 30, a diaphragm structure layer disposed on the side of the first electrode 21 layer away from the substrate 30, and a second electrode 28 layer disposed on the side of the diaphragm structure layer away from the substrate 30. Multiple cavities 200 are provided between the first electrode 21 layer and the diaphragm structure layer. Figure 20As shown, at least one support pillar 25 is disposed within the cavity 200. The cavity 200 has a first height H1, and the support pillar 25 has a second height H2, which is smaller than the first height H1. The first height H1 and the second height H2 are dimensions perpendicular to the substrate 30. By forming at least one support pillar 25 within the cavity 200 located between the first electrode 21 layer and the diaphragm structure layer, the support pillar 25 provides support for the diaphragm structure layer. During subsequent processes and use, this reduces the space required for the diaphragm structure layer to move towards the substrate 30, effectively preventing the diaphragm structure layer from collapsing. This ensures that the diaphragm structure layer still has the ability to vibrate in space. The placement of the support pillar 25 does not affect the normal operation of the diaphragm structure layer, thus guaranteeing the vibration performance of the ultrasonic transducer substrate.

[0048] In an exemplary embodiment, the ratio of the first height H1 to the second height H2 can range from approximately 1.05 to 1.1. For example, the ratio of the first height H1 to the second height H2 can be approximately 1.075.

[0049] In an exemplary embodiment, the first electrode 21 layer includes at least one first electrode 21. In this embodiment, there are multiple first electrodes 21, each corresponding to a plurality of cavity portions 201. The second electrode 28 layer includes at least one second electrode 28. In this embodiment, there are multiple second electrodes 28, each corresponding to a plurality of first electrodes 21, and the orthographic projection of the second electrode 28 on the substrate 30 at least partially overlaps with the orthographic projection of the first electrode 21 on the substrate 30. The orthographic projection of the support pillar 25 on the substrate 30 at least partially overlaps with the orthographic projection of the first electrode 21 on the substrate 30. On a plane perpendicular to the substrate 30, each first electrode 21 corresponds to each cavity portion 201, at least one support pillar 25, and each second electrode 28, and is disposed from one side of the substrate 30 toward the side away from the substrate 30. In this embodiment, there are three support pillars 25 corresponding to each first electrode 21.

[0050] In an exemplary embodiment, the first electrode 21 layer further includes a first insulating layer 22 disposed on the side of the first electrode 21 away from the substrate 30, and a support post 25 disposed on the side of the first insulating layer 22 away from the substrate 30 and connected to the first insulating layer 22.

[0051] In an exemplary embodiment, the first insulating layer 22 can connect the entire diaphragm structure layer and the second electrode 28 layer to the drive circuit layer 10, and can wrap the first electrode 21 to prevent leakage of the first electrode 21.

[0052] In an exemplary embodiment, the diaphragm structure layer includes a first diaphragm layer 24, a second diaphragm layer 26 disposed on the side of the first diaphragm layer 24 away from the substrate 30, and a third diaphragm layer 27 disposed on the side of the second diaphragm layer 26 away from the substrate 30. A gap is formed between the surface of the support column 25 away from the substrate 30 and the surface of the first diaphragm layer 24 close to the substrate 30, so that the diaphragm structure layer still has space to vibrate. The setting of the support column 25 will not affect the normal operation of the diaphragm structure layer, thus ensuring the vibration performance of the ultrasonic transducer substrate.

[0053] In an exemplary embodiment, the height of the gap can be approximately to The height of the gap is a dimension perpendicular to the direction of the base 30. For example, the height of the gap can be approximately... about.

[0054] In an exemplary embodiment, the cross-sectional shape of the support column 25 in the direction perpendicular to the base 30 can be, but is not limited to, cylindrical or trapezoidal. The first width W1 of the surface of the support column 25 away from the base 30 can be less than or equal to the second width W2 of the surface of the support column 25 near the base 30. The first width W1 and the second width W2 are dimensions parallel to the direction of the base 30. Figure 20 As shown. Due to the small area of ​​the support column 25, the influence of the charge on the support column 25 can be ignored.

[0055] In an exemplary embodiment, the ratio of the first width W1 to the second width W2 can range from approximately 0.5 to 0.8. For example, the ratio of the first width W1 to the second width W2 can be approximately 0.65.

[0056] In an exemplary embodiment, the cross-sectional shape of the support column 25 in the direction parallel to the base 30 can be, but is not limited to, circular, elliptical, rectangular, pentagonal, or hexagonal.

[0057] In an exemplary embodiment, at least one first via 100 is provided on the first diaphragm layer 24, and the second diaphragm layer 26 is capable of filling the first via 100. In this embodiment, in Figure 2 In the cross-sectional direction shown, two first vias 100 can be provided. The two first vias 100 are respectively provided on both sides of the first electrode 21, and the orthographic projection of the first via 100 on the substrate 30 does not overlap with the orthographic projection of the first electrode 21 on the substrate 30. Since the first electrode 21 is provided corresponding to the cavity portion 201, the above-mentioned arrangement of the first vias 100 can be far away from the main vibration area of ​​the diaphragm structure layer, reducing the influence of the first vias 100 on the vibration parameters of the diaphragm structure layer and avoiding vibration causing cracks in the diaphragm structure layer at the location of the first via 100.

[0058] In an exemplary embodiment, the orthographic projection of the first via 100 on the substrate 30 does not overlap with the orthographic projection of the second electrode 28 on the substrate 30.

[0059] In an exemplary embodiment, the second electrode 28 layer further includes a second insulating layer 29 disposed on the side of the second electrode 28 away from the substrate 30.

[0060] The following is an illustrative example of the fabrication process of an ultrasonic transducer. The "patterning process" mentioned in this application, for metallic, inorganic, or transparent conductive materials, includes processes such as depositing a film, coating the film with photoresist, mask exposure, development, etching, and photoresist stripping; for organic materials, it includes processes such as coating the organic material, mask exposure, and development. Deposition can be performed using any one or more of sputtering, evaporation, and chemical vapor deposition; coating can be performed using any one or more of spraying, spin coating, and inkjet printing; etching can be performed using any one or more of dry etching and wet etching. This application does not limit the methods used. "Thin film" refers to a thin film made of a certain material on a substrate 30 using deposition, coating, or other processes. If the "thin film" does not require a patterning process during the entire fabrication process, it can also be called a "layer." If the "thin film" requires a patterning process during the entire fabrication process, it is called a "thin film" before the patterning process and a "layer" after the patterning process. The "layer" after the patterning process contains at least one "pattern." The phrase "A and B are set in the same layer" in this application means that A and B are formed simultaneously through the same patterning process, and the "thickness" of the film layer is the dimension of the film layer in the direction perpendicular to the display substrate. In the exemplary embodiments of this application, "the orthographic projection of B is within the range of the orthographic projection of A" or "the orthographic projection of A includes the orthographic projection of B" means that the boundary of the orthographic projection of B falls within the boundary range of the orthographic projection of A, or the boundary of the orthographic projection of A overlaps with the boundary of the orthographic projection of B.

[0061] The fabrication process of the ultrasonic transducer in the exemplary embodiments of this application may include the following operations.

[0062] 1. Fabricate the driving circuit layer 10. In an exemplary embodiment, the driving circuit layer 10 may include a first transistor 11, a second transistor 12, and a capacitor 13, such as... Figure 4 As shown. The driving circuit layer 10 can be fabricated using conventional processes, which will not be described in detail here.

[0063] 2. Fabrication of the ultrasonic transducer substrate:

[0064] (1) Forming a first electrode 21 layer pattern. In an exemplary embodiment, forming the first electrode 21 layer pattern may include: depositing a first conductive film on the substrate 30 on which the aforementioned pattern is formed, and patterning the first conductive film using a patterning process to form a first electrode 21 layer pattern disposed on the side of the driving circuit layer 10 away from the substrate 30. The first electrode 21 layer pattern may include at least a first electrode 21, and the first electrode 21 may be connected to the capacitor 13 through a via 300, such as... Figure 5 As shown.

[0065] In an exemplary embodiment, the material of the first electrode 21 includes, but is not limited to, molybdenum (Mo) or aluminum (Al).

[0066] In an exemplary embodiment, the thickness of the first electrode 21 can be approximately [missing information]. to For example, the thickness of the first electrode 21 can be approximately about.

[0067] (2) Forming the pattern of the sacrificial layer 23. In an exemplary embodiment, forming the pattern of the sacrificial layer 23 may include:

[0068] A first insulating film and a sacrificial film are sequentially deposited on the substrate 30 on which the aforementioned pattern is formed. The sacrificial film is patterned using a patterning process to form a first insulating layer 22 disposed on the side of the first electrode 21 pattern away from the substrate 30 and a sacrificial layer 23 disposed on the side of the first insulating layer 22 away from the substrate 30. Figures 6 to 8 As shown, Figure 6 for Figure 1 A sectional view along the AA direction. Figure 7 for Figure 1 A cross-sectional view along the BB direction. The sacrificial layer 23 includes at least sacrificial portions 231 and sacrificial connection portions 232. In an exemplary embodiment, there are multiple sacrificial portions 231, each corresponding to a first electrode 21. Each sacrificial portion 231 is connected to four sacrificial connection portions 232. The four sacrificial connection portions 232 are evenly distributed around the circumference of the sacrificial portion 231.

[0069] In an exemplary embodiment, the material of the first insulating layer 22 may include, but is not limited to, silicon nitride (SiNx) or silicon oxide (SiOx), and may be a single-layer structure or a multi-layer structure. The first insulating layer 22 may be referred to as a buffer layer, which can improve the water and oxygen resistance of the pattern of the first electrode 21 layer and prevent water and oxygen from seeping down from the first electrode 21 layer into the pattern of the first electrode 21 layer and the driving circuit layer 10 and affecting its electrical characteristics.

[0070] In an exemplary embodiment, the thickness of the first insulating layer 22 can be approximately to For example, the thickness of the first insulating layer 22 can be approximately about.

[0071] In an exemplary embodiment, the material of the sacrificial layer 23 may include, but is not limited to, molybdenum (Mo), copper (Cu), or aluminum (Al).

[0072] In an exemplary embodiment, the thickness of the sacrificial layer 23 can be approximately [missing information]. For example, the thickness of the sacrificial layer 23 can be approximately about.

[0073] (3) Forming a pattern for the first diaphragm layer 24. In an exemplary embodiment, forming a pattern for the first diaphragm layer 24 may include:

[0074] A first vibrating film is deposited on the substrate 30 on which the aforementioned pattern is formed. The first vibrating film is then patterned using a patterning process to form a first diaphragm layer 24 disposed on the side of the sacrificial layer 23 away from the substrate 30. At least one first via 100 is provided on the first diaphragm layer 24. The first vibrating film within the first via 100 is etched away, exposing the surface of the sacrificial layer 23. Figure 9 and Figure 10 As shown, Figure 9 for Figure 1 A sectional view along the AA direction. Figure 10 for Figure 1 A cross-sectional view along the BB direction. In an exemplary embodiment, each first electrode 21 corresponds to four first vias 100. The four first vias 100 are disposed circumferentially on the first electrode 21, and the orthographic projection of the first via 100 on the substrate 30 does not overlap with the orthographic projection of the first electrode 21 on the substrate 30, but at least partially overlaps with the orthographic projection of the sacrificial connection 232 on the substrate 30, so as to expose the sacrificial connection 232.

[0075] In an exemplary embodiment, the first diaphragm layer 24 may include, but is not limited to, one or more layers of polycrystalline silicon (p-Si), silicon nitride (SiN), and silicon oxide (SiO). For example, the first diaphragm layer 24 is a SiN layer, a transparent layer.

[0076] In an exemplary embodiment, the thickness of the first diaphragm layer 24 can be approximately [missing information]. For example, the thickness of the transparent layer can be approximately about.

[0077] (4) Forming a cavity 200 pattern. In an exemplary embodiment, forming a cavity 200 pattern may include: using a first via 100, removing the sacrificial layer 23 using a wet etching process to form a plurality of cavities 200 between the first insulating layer 22 and the first diaphragm layer 24. Each cavity 200 includes a cavity portion 201 formed after removing the sacrificial portion 231 and a cavity connecting portion 202 formed after removing the sacrificial connecting portion 232. The cavity portion 201 communicates with the cavity connecting portion 202. The first via 100 communicates with the cavity connecting portion 202, such as... Figure 11 and Figure 12 As shown, Figure 11 for Figure 1 A sectional view along the AA direction. Figure 12 for Figure 1 A sectional view along the BB direction.

[0078] In an exemplary embodiment, the thickness of the cavity 200 is the same as the thickness of the sacrificial layer 23. For example, the thickness of the cavity 200 may be approximately [missing information]. about.

[0079] (5) Forming a support structure pattern. In an exemplary embodiment, forming a support structure pattern may include:

[0080] On the substrate 30 on which the aforementioned pattern is formed, a support film is first coated. The support film enters the cavity 200 through the capillary action of the first through-hole 100 and is then subjected to a pre-baking process.

[0081] Subsequently, the supporting film within the cavity 200 is patterned using a patterning process to form a transition structure, such as... Figure 13 and Figure 14 As shown, Figure 13 for Figure 1 A sectional view along the AA direction. Figure 14 for Figure 1 A sectional view of the section along the BB direction.

[0082] In an exemplary embodiment, the transition structure may include at least one transition post 25a, the height of which H1 is consistent with the thickness of the cavity 200.

[0083] A subsequent baking process is performed, causing the transition structure to shrink and form a support structure located on the side of the first insulating layer 22 away from the substrate 30, such as... Figure 15 and Figure 16 As shown, Figure 15 for Figure 1 A sectional view along the AA direction. Figure 16 for Figure 1 A sectional view of the section along the BB direction.

[0084] In an exemplary implementation, such as Figure 20 As shown, the support structure may include at least one support column 25. The height H2 of the support column 25 is less than the thickness of the cavity 200, so that a gap is formed between the support column 25 and the first diaphragm layer 24, which does not affect the operation of the first diaphragm layer 24. At the same time, since the area of ​​the support column 25 is small, its influence on the charge can be ignored.

[0085] In an exemplary embodiment, the orthographic projection of the support post 25 on the substrate 30 at least partially overlaps with the orthographic projection of the first electrode 21 on the substrate 30.

[0086] In an exemplary embodiment, the cross-sectional shape of the support column 25 in the direction parallel to the base 30 can be circular, elliptical, rectangular, pentagonal, or hexagonal.

[0087] In an exemplary embodiment, the cross-sectional shape of the support column 25 in the direction perpendicular to the base 30 can be cylindrical or trapezoidal. The first width W1 of the surface of the support column 25 away from the base 30 can be less than or equal to the second width W2 of the surface of the support column 25 near the base 30. The first width W1 and the second width W2 are dimensions parallel to the direction of the base 30. Figure 20 As shown.

[0088] In an exemplary embodiment, the support film can be a low-viscosity, easy-to-coat, good-insulating, and high-elastic-recovery film among ultraviolet positive and negative photoresists, deep ultraviolet photoresists, X-ray photoresists, electron beam photoresists, or ion beam photoresists.

[0089] (6) Forming a second electrode 28-layer pattern. In an exemplary embodiment, forming the second electrode 28-layer pattern may include:

[0090] A second vibrating film is first deposited on the substrate 30 where the aforementioned pattern is formed, forming a second diaphragm layer 26 covering the side of the first diaphragm layer 24 away from the substrate 30. Then, a third vibrating film is coated on the side of the second diaphragm layer 26 away from the substrate 30. After curing, a third diaphragm layer 27 is formed on the side of the second diaphragm layer 26 away from the substrate 30. Subsequently, a second conductive film is deposited on the side of the third diaphragm layer 27 away from the substrate 30. The second conductive film is then patterned using a patterning process to form a second electrode 28 layer pattern on the side of the third diaphragm layer 27 away from the substrate 30. The second electrode 28 layer pattern may include at least one second electrode 28, such as... Figure 17 and Figure 18 As shown, Figure 17 for Figure 1 A sectional view along the AA direction. Figure 18 for Figure 1 A cross-sectional view along the BB direction. The second electrode 28 can be electrically connected to the drive voltage line.

[0091] In an exemplary embodiment, the material of the second diaphragm layer 26 may be any one or more of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), and may be a single layer, multiple layers, or a composite layer. The second diaphragm layer 26 may be referred to as the first passivation (PVX) layer.

[0092] In an exemplary embodiment, the thickness of the second diaphragm layer 26 can be approximately For example, the thickness of the second diaphragm layer 26 can be approximately about.

[0093] In an exemplary embodiment, the material of the third diaphragm layer 27 is an organic material, such as resin. It can be a single layer, multiple layers, or a composite layer.

[0094] The third diaphragm layer 27 can be called a planar (PLN) layer or a resin layer.

[0095] In an exemplary embodiment, the thickness of the third diaphragm layer 27 can be approximately For example, the thickness of the third diaphragm layer 27 can be approximately about.

[0096] In an exemplary embodiment, the material of the second electrode 28 includes, but is not limited to, molybdenum (Mo) or aluminum (Al).

[0097] In an exemplary embodiment, the thickness of the second electrode 28 can be approximately [missing information]. to For example, the thickness of the second electrode 28 can be approximately about.

[0098] In an exemplary embodiment, the orthographic projection of the second electrode 28 onto the substrate 30 at least partially overlaps with the orthographic projection of the first electrode 21 onto the substrate 30. The orthographic projection of the second electrode 28 onto the substrate 30 also at least partially overlaps with the orthographic projection of the support post 25 onto the substrate 30.

[0099] (7) Forming a second insulating layer 29. In an exemplary embodiment, forming the second insulating layer 29 may include:

[0100] A second insulating film is deposited on the substrate 30 where the aforementioned pattern is formed, forming a second insulating layer 29 covering the pattern of the second electrode 28 layers, as shown. Figure 19 As shown, Figure 19 for Figure 1 A cross-sectional view along the AA direction.

[0101] In an exemplary embodiment, the material of the second insulating layer 29 may be any one or more of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), and may be a single layer, multiple layers, or a composite layer.

[0102] The second insulating layer 29 can be referred to as the second passivation (PVX) layer.

[0103] In an exemplary embodiment, the thickness of the second insulating layer 29 can be approximately [missing information]. to For example, the thickness of the second insulating layer 29 can be approximately about.

[0104] The structure and fabrication process of the ultrasonic transducer described in this exemplary embodiment are merely illustrative. In the exemplary embodiment, the corresponding structure and the patterning process can be modified and increased or decreased according to actual needs.

[0105] An exemplary embodiment of this application also provides a method for fabricating an ultrasonic transducer substrate. In an exemplary embodiment, the method for fabricating an ultrasonic transducer substrate may include:

[0106] A first electrode 21 layer is formed on the substrate 30;

[0107] A diaphragm structure layer is formed on the first electrode 21 layer. A cavity 200 is provided between the first electrode 21 layer and the diaphragm structure layer. At least one support column 25 is provided in the cavity 200. The cavity 200 has a first height H1, and the support column 25 has a second height H2. The second height H2 is smaller than the first height H1. The first height H1 and the second height H2 are dimensions perpendicular to the direction of the substrate 30.

[0108] A second electrode layer 28 is formed on the side of the diaphragm structure layer away from the substrate 30.

[0109] In an exemplary embodiment, forming a diaphragm structure layer on the first electrode 21 layer may include:

[0110] A first diaphragm layer 24 is formed on the first electrode 21 layer, a cavity 200 is formed between the first diaphragm layer 24 and the first electrode 21 layer, and at least one support column 25 is formed in the cavity 200.

[0111] A second diaphragm layer 26 and a third diaphragm layer 27 are formed sequentially in the first diaphragm layer 24.

[0112] In an exemplary embodiment, a first diaphragm layer 24 is formed on the first electrode 21 layer, a cavity 200 is formed between the first electrode 21 layer and the first diaphragm layer 24, and at least one support post 25 is formed within the cavity 200, which may include:

[0113] A sacrificial film is formed on the first electrode 21 layer, and a sacrificial layer 23 is formed by a patterning process. The sacrificial layer 23 includes at least a sacrificial portion 231 and a sacrificial connection portion 232.

[0114] A first diaphragm layer 24 is formed on the sacrificial layer 23. At least one first via 100 is provided on the first diaphragm layer 24. The orthographic projection of the first via 100 on the substrate 30 at least partially overlaps with the orthographic projection of the sacrificial connection portion 232 on the substrate 30.

[0115] Using the first via 100, the sacrificial layer 23 is removed by etching process, and a cavity 200 is formed between the first electrode 21 layer and the first diaphragm layer 24.

[0116] At least one support column 25 is formed within the cavity 200.

[0117] In an exemplary embodiment, forming at least one support column 25 within the cavity 200 may include:

[0118] A supporting membrane is filled into the cavity 200;

[0119] The support film is patterned by a patterning process to form at least one support column 25a, the support column 25a having a second height H2;

[0120] The support column 25a is formed by shrinking the film through a post-drying process.

[0121] In an exemplary embodiment, filling the cavity 200 with a support film may include...

[0122] A support film is coated on the first diaphragm layer 24 so that the support film enters the cavity 200 by the capillary action of the first through hole 100.

[0123] In an exemplary embodiment, the first diaphragm layer 24 is a transparent layer.

[0124] This application also provides an ultrasonic transducer, including the ultrasonic transducer substrate described in the foregoing embodiments. The ultrasonic transducer can be used for fingerprint recognition, thereby enabling functions such as fingerprint unlocking. Because the ridges and valleys on the finger surface reflect ultrasonic signals with different intensities, the ultrasonic energy reflected by the ridges and valleys of the finger differs. Converting this energy difference into a difference in electrical signals allows for imaging of the ridges and valleys of the fingerprint, thus enabling fingerprint recognition. The fingerprint recognition device can be installed in any product or component with fingerprint recognition functionality, such as mobile phones, tablets, access control devices, monitors, laptops, digital photo frames, or navigators.

[0125] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An ultrasonic transducer substrate, characterized by, The diaphragm structure layer is provided on the first electrode layer, and the second electrode layer is provided on the diaphragm structure layer away from the substrate. The first electrode layer and the diaphragm structure layer are provided with a cavity, and at least one support column is arranged in the cavity. The cavity has a first height, and the support column has a second height. The second height is less than the first height. The first height and the second height are the dimensions in the direction perpendicular to the substrate. The at least one support column is formed by: forming a sacrificial film on the first electrode layer, forming a sacrificial layer by a patterning process, and the sacrificial layer at least includes a sacrificial part and a sacrificial connecting part; forming a first diaphragm layer on the sacrificial layer, and the first diaphragm layer is provided with at least one first via hole. The first via hole has no overlap with the first electrode in the orthographic projection on the substrate, and the first via hole has no overlap with the second electrode in the orthographic projection on the substrate; using the first via hole, removing the sacrificial layer by an etching process to form a cavity without a support column between the first electrode layer and the first diaphragm layer; coating a support film on the first diaphragm layer, so that the support film enters the cavity without a support column by capillary action of the first via hole; patterning the support film by a patterning process to form at least one support column before shrinking; forming the at least one support column by shrinking the at least one support column before shrinking through a post-baking process; The first via hole is filled with a second diaphragm layer, and the second diaphragm layer also fills the space below the first via hole in the cavity.

2. The ultrasonic transducer substrate of claim 1, wherein, The ratio of the first height to the second height ranges from 1.05 to 1.

1.

3. The ultrasonic transducer substrate of claim 1, wherein, The first electrode layer includes at least one first electrode, and the second electrode layer includes at least one second electrode. The second electrode has at least partial overlap with the first electrode in the orthographic projection on the substrate. The support column has at least partial overlap with the first electrode in the orthographic projection on the substrate.

4. The ultrasonic transducer substrate of claim 3, wherein, The first electrode layer further includes a first insulating layer provided on the side of the first electrode away from the substrate. The support column is provided on the side of the first insulating layer away from the substrate and connected with the first insulating layer.

5. The ultrasonic transducer substrate of claim 1, wherein, The diaphragm structure layer includes the first diaphragm layer, the second diaphragm layer provided on the side of the first diaphragm layer away from the substrate, and the third diaphragm layer provided on the side of the second diaphragm layer away from the substrate. The surface of the support column away from the substrate and the surface of the first diaphragm layer close to the substrate form a gap.

6. The ultrasonic transducer substrate of claim 5, wherein, The height of the gap ranges from 150 Å to 300 Å. The height of the gap is the dimension in the direction perpendicular to the substrate.

7. The ultrasonic transducer substrate of claim 5, wherein, The first width of the support post away from the side surface of the substrate is less than or equal to the second width of the support post close to the side surface of the substrate, the first width and the second width being dimensions parallel to the direction of the substrate.

8. The ultrasonic transducer substrate of claim 7, wherein, The ratio of the first width to the second width ranges from 0.5 to 0.

8.

9. The ultrasonic transducer substrate of claim 5, wherein, The first diaphragm layer is a transparent layer.

10. The ultrasonic transducer substrate of claim 3, wherein, The second electrode layer further comprises a second insulating layer disposed on the second electrode away from the side surface of the substrate.

11. An ultrasonic transducer, characterized by An ultrasonic transducer substrate as claimed in any one of claims 1 to 10.

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