CN117139120A - Ultrasonic transducer substrate and ultrasonic transducer - Google Patents

Abstract

The application discloses an ultrasonic transducer substrate and an ultrasonic transducer, and relates to the technical field of ultrasonic transducers. This ultrasonic transducer base plate is through being located at least one support column of formation in the cavity between first electrode layer and the vibrating diaphragm structural layer, and the support column can provide the support to the vibrating diaphragm structural layer, and when follow-up technology and use, reduce vibrating diaphragm structural layer and move the space to base one side, can effectively avoid the vibrating diaphragm structural layer to take place to collapse, simultaneously, the cavity has first height, the support column has the second height, the second height is less than first height, first height with the second height is perpendicular to the size on the base direction, so still has the space to take place to vibrate for the vibrating diaphragm structural layer, and the setting of support column can not influence the normal work of vibrating diaphragm structural layer, has guaranteed ultrasonic transducer base plate's vibration performance.

Description

Ultrasonic transducer substrate and ultrasonic transducer

Technical Field

The application relates to the technical field of ultrasonic transducers, in particular to an ultrasonic transducer substrate and an ultrasonic transducer.

Background

The ultrasonic wave has the advantages of good directional bundling property and high energy density in the propagation process, and simultaneously can not produce noise pollution affecting the life and work of people, and can not produce electromagnetic pollution like electromagnetic waves. Therefore, ultrasonic waves are widely used in many industrial fields. Meanwhile, the ultrasonic waves can also be used for ultrasonic diagnosis, ultrasonic flaw detection, ultrasonic polishing, ultrasonic stirring, ultrasonic treatment, ultrasonic imaging and ultrasonic demodulation audible sound.

In various ultrasound applications, however, the ultrasound transducer is the most central device. Among various ultrasonic sensors, the capacitive micromachined ultrasonic transducer (CUMT) has a wide application prospect. The CMUT adopts a micromechanical technology and a capacitive sensing principle, and can realize high-precision and high-sensitivity ultrasonic detection and measurement. The basic structure of the CMUT is a parallel plate capacitor consisting of a vibrating diaphragm structural layer and an electrode pair, and when a direct current voltage is applied, electrostatic force is generated to be balanced with the tension of the vibrating diaphragm structural layer. An alternating voltage is applied to the vibrating diaphragm structural layer, and the vibrating diaphragm structural layer resonates to push surrounding media to do work so as to generate a large amount of ultrasonic waves. When ultrasonic waves act on the diaphragm structure layer, the capacitance value of the capacitor is changed, so that an electric signal is generated.

Because the cavity exists in the CMUT, the inorganic membrane layer exists in the vibrating membrane structural layer, and certain stress exists, the vibrating membrane structural layer is easy to collapse in the subsequent process and use, and the CMUT is invalid.

Disclosure of Invention

The following is a summary of the subject matter of the detailed description of the application. This summary is not intended to limit the scope of the claims.

The technical problem to be solved by the embodiment of the application is to provide an ultrasonic transducer substrate and an ultrasonic transducer, so as to solve the technical problem that the ultrasonic sensor is invalid due to the fact that a vibrating diaphragm structural layer is easy to collapse in the follow-up process and use of the existing structure.

In one aspect, an embodiment of the present application provides an ultrasonic transducer substrate, including a first electrode layer disposed on a substrate, a diaphragm structure layer disposed on a side of the first electrode layer away from the substrate, and a second electrode layer disposed on a side of the diaphragm structure layer away from the substrate, wherein a cavity is disposed between the first electrode layer and the diaphragm structure layer, at least one support column is disposed in the cavity, the cavity has a first height, the support column has a second height, the second height is smaller than the first height, and the first height and the second height are perpendicular to the dimensions in the direction of the substrate.

On the other hand, the embodiment of the application also provides an ultrasonic transducer, which comprises the ultrasonic transducer substrate.

The application provides an ultrasonic transducer substrate and an ultrasonic transducer, wherein at least one support column is formed in a cavity between a first electrode layer and a vibrating diaphragm structural layer, the support column can provide support for the vibrating diaphragm structural layer, when the vibrating diaphragm structural layer is used in the subsequent process, the moving space of the vibrating diaphragm structural layer to one side of the substrate is reduced, collapse of the vibrating diaphragm structural layer can be effectively avoided, meanwhile, the cavity is provided with a first height, the support column is provided with a second height, the second height is smaller than the first height, the first height and the second height are vertical to the dimension in the direction of the substrate, so that the vibrating diaphragm structural layer still has the capacity of vibrating spatially, the arrangement of the support column does not influence the normal operation of the vibrating diaphragm structural layer, and the vibration performance of the ultrasonic transducer substrate is ensured.

Other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description.

Drawings

The accompanying drawings are included to provide an understanding of the principles of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain, without limitation, the principles of the application.

FIG. 1 is a schematic plan view of an ultrasonic transducer substrate according to an embodiment of the present application;

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is a cross-sectional view taken along the direction B-B in FIG. 1;

FIG. 4 is a schematic diagram of a driving circuit layer according to an embodiment of the present application;

FIG. 5 is a schematic diagram of an embodiment of the present application after forming a first conductive layer pattern;

FIG. 6 is a schematic view of a cross-sectional view of A-A after forming a sacrificial layer pattern according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a sacrificial layer pattern formed according to an embodiment of the present application, with a B-B cross-sectional position;

FIG. 8 is a schematic plan view illustrating a first diaphragm layer pattern according to an embodiment of the present application;

FIG. 9 is a schematic diagram of a first diaphragm layer patterned according to an embodiment of the present application, with A-A being a cross-sectional position;

FIG. 10 is a schematic diagram of a first diaphragm layer patterned according to an embodiment of the present application, with a B-B cross-sectional position;

FIG. 11 is a schematic view of a cross-sectional view of A-A after cavity patterning in accordance with an embodiment of the present application;

FIG. 12 is a schematic view of a cavity pattern formed in accordance with an embodiment of the present application, shown in section in the B-B direction;

FIG. 13 is a schematic view of an embodiment of the present application after forming a transition structure, A-A being a cross-sectional position;

FIG. 14 is a schematic view of a transition structure formed according to an embodiment of the present application, with a B-B cross-sectional view;

FIG. 15 is a schematic view of an embodiment of the present application after forming a support structure, A-A in cross-sectional position;

FIG. 16 is a schematic view of a support structure formed in accordance with an embodiment of the present application, shown in section in position B-B;

FIG. 17 is a schematic view of a cross-sectional view of A-A after forming a second conductive layer pattern according to an embodiment of the present application;

FIG. 18 is a schematic diagram of a second conductive layer patterned according to an embodiment of the present application, B-B being a cross-sectional position;

FIG. 19 is a schematic view showing a cross-sectional position A-A after forming a second insulating layer according to an embodiment of the present application;

fig. 20 is an enlarged schematic view of the C portion in fig. 19.

Reference numerals illustrate:

m, an ultrasonic transduction unit; 10. a driving circuit layer; 11. a first transistor; 12. a second transistor; 13. a capacitor; 21. a first electrode; 22. a first insulating layer; 23. a sacrificial layer; 231. a sacrificial portion; 232. a sacrificial connection; 24. a first diaphragm layer; 25. a support column; 25a, a transition column; 26. a second diaphragm layer; 27. a third diaphragm layer; 28. a second electrode; 29. a second insulating layer; 30. a substrate; 100. a first via; 200. a cavity; 201. a cavity portion; 202. a cavity connecting part; 300. and (5) a via hole.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings. Note that embodiments may be implemented in a number of different forms. One of ordinary skill in the art can readily recognize the fact that the manner and content of the application can be varied in a wide variety of forms without departing from the spirit and scope of the application. Therefore, the present application should not be construed as being limited to the following embodiments. Embodiments of the application and features of the embodiments may be combined with one another arbitrarily without conflict.

The scale of the drawings in the present application may be used as references in the actual process, but is not limited thereto. For example: the width-to-length ratio of the channel, the thickness and the spacing of each film layer, and the width and the 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 number shown in the drawings, the drawings described in the present application are only schematic structures, and one embodiment of the present application is not limited to the shapes or the numerical values shown in the drawings, etc.

The ordinal numbers of "first", "second", "third", etc. in the present specification are provided to avoid mixing of constituent elements, and are not intended to be limited in number.

In the present specification, for convenience, words such as "middle", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, which indicate an azimuth or a positional relationship, are used to describe the positional relationship of the constituent elements with reference to the drawings, only for convenience of description of the present specification and simplification of the description, and do not indicate or imply that the apparatus or elements referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present application. The positional relationship of the constituent elements is appropriately changed according to the direction in which the respective constituent elements are described. Therefore, the present application is not limited to the words described in the specification, and may be appropriately replaced according to circumstances.

In this specification, the terms "mounted," "connected," and "connected" are to be construed broadly, unless explicitly stated or limited otherwise. For example, it may be a fixed connection, a removable connection, or an integral connection; may be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intermediate members, or may be in communication with the interior of two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

In this specification, a transistor means an element including at least three terminals of a gate electrode, a drain electrode, and a source electrode. The transistor has a channel region between a drain electrode (a drain electrode terminal, a drain region, or a drain electrode) and a source electrode (a source electrode terminal, a source region, or a source electrode), and a current can flow through the drain electrode, the channel region, and the source electrode. Note that in this specification, a channel region refers to a region through which current mainly flows.

In this specification, the first electrode may be a drain electrode, the second electrode may be a source electrode, or the first electrode may be a source electrode and the second electrode may be a drain electrode. In the case of using a transistor having opposite polarity, or in the case of a change in the direction of current during circuit operation, the functions of the "source electrode" and the "drain electrode" may be interchanged. Therefore, in this specification, "source electrode" and "drain electrode" may be exchanged, and "source terminal" and "drain terminal" may be exchanged.

In this specification, "electrically connected" includes a case where constituent elements are connected together by an element having some electric action. The "element having a certain electric action" is not particularly limited as long as it can transmit and receive an electric signal between the constituent elements connected. Examples of the "element having some electric action" include not only an electrode and a wiring but also a switching element such as a transistor, a resistor, an inductor, a capacitor, other elements having various functions, and the like.

In the present specification, "parallel" means a state in which two straight lines form an angle of-10 ° or more and 10 ° or less, and therefore, a state in which the angle is-5 ° or more and 5 ° or less is also included. The term "perpendicular" refers to a state in which the angle formed by two straight lines is 80 ° or more and 100 ° or less, and thus includes a state in which the angle is 85 ° or more and 95 ° or less.

In this specification, "film" and "layer" may be exchanged with each other. For example, the "conductive layer" may be sometimes replaced with a "conductive film". In the same manner, the "insulating film" may be replaced with the "insulating layer" in some cases.

The triangle, rectangle, trapezoid, pentagon or hexagon, etc. in this specification are not strictly defined, but may be approximated to triangle, rectangle, trapezoid, pentagon or hexagon, etc., and there may be some small deformation due to tolerance, and there may be lead angles, arc edges, deformation, etc.

The term "about" in the present application means not strictly limited to numerical values within the limits of permissible process and measurement errors.

Fig. 1 is a schematic plan view of an ultrasonic transducer according to an embodiment of the present application. As shown in fig. 1, the main structure of the ultrasonic transducer according to the embodiment of the application may include a plurality of ultrasonic transducer units M distributed in an array, each ultrasonic transducer unit M corresponds to one second electrode 28 and a plurality of first vias 100, the plurality of first vias 100 are uniformly distributed around the circumference of the corresponding ultrasonic transducer unit M, and the sacrificial layer 23 is removed by using the first vias 100 to form a plurality of cavities 200. The cavity 200 includes a cavity portion 201 and a cavity connection portion 202, the cavity connection portion 202 being connected between the cavity portion 201 and the first via 100. The plurality of ultrasonic transducer units M are disposed in a plurality of cavities 200 in one-to-one correspondence. Two first through holes 100 are shared by adjacent ultrasonic transduction units M, so that the opening amount of the first through holes 100 is reduced, and the preparation efficiency is improved.

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1. FIG. 3 is a sectional view taken along the direction B-B in FIG. 1. As shown in fig. 2 and 3, the ultrasonic transducer substrate includes, on a plane perpendicular to the substrate 30, the driving circuit layer 10 provided on the substrate 30, the first electrode 21 layer provided on a side of the driving circuit layer 10 away from the substrate 30, the diaphragm structure layer provided on a side of the first electrode 21 layer away from the substrate 30, and the second electrode 28 layer provided on a side of the diaphragm structure layer away from the substrate 30, with a plurality of cavities 200 provided between the first electrode 21 layer and the diaphragm structure layer. As shown in fig. 20, at least one support column 25 is disposed in the cavity 200, the cavity 200 has a first height H1, the support column 25 has a second height H2, the second height H2 is smaller than the first height H1, and the first height H1 and the second height H2 are dimensions perpendicular to the substrate 30. So through forming at least one support column 25 in the cavity 200 that is located between first electrode 21 layer and the vibrating diaphragm structural layer, the support column 25 can provide the support to the vibrating diaphragm structural layer, when follow-up technology and use, reduce vibrating diaphragm structural layer and remove the space to substrate 30 one side, can effectively avoid the vibrating diaphragm structural layer to take place to collapse, so make vibrating diaphragm structural layer still have the ability that the space takes place to vibrate, the setting of support column 25 can not influence the normal work of vibrating diaphragm structural layer, has guaranteed the vibration performance of ultrasonic transducer base plate.

In an exemplary embodiment, the ratio of the first height H1 to the second height H2 may range from about 1.05 to about 1.1. For example, the ratio of the first height H1 to the second height H2 may be about 1.075 or so.

In an exemplary embodiment, the first electrode 21 layer includes at least one first electrode 21. In the embodiment of the present application, the number of the first electrodes 21 is plural, and the plural first electrodes 21 are in one-to-one correspondence with the plural cavity portions 201. The second electrode 28 layer includes at least one second electrode 28. In the embodiment of the present application, the number of the second electrodes 28 is plural, the plurality of second electrodes 28 are in one-to-one correspondence with the plurality of first electrodes 21, and the front projection of the second electrodes 28 on the substrate 30 at least partially overlaps with the front projection of the first electrodes 21 on the substrate 30. The orthographic projection of the support post 25 onto the substrate 30 at least partially overlaps the orthographic projection of the first electrode 21 onto the substrate 30. Each first electrode 21 corresponds to each cavity portion 201, at least one support column 25, and each second electrode 28 on a plane perpendicular to the substrate 30, and is disposed from a side of the substrate 30 to a side away from the substrate 30. In the embodiment of the present application, the number of the support columns 25 corresponding to each first electrode 21 is three.

In an exemplary embodiment, the first electrode 21 layer further includes a first insulating layer 22 disposed on a side of the first electrode 21 remote from the substrate 30, and the support pillars 25 are disposed on a side of the first insulating layer 22 remote from the substrate 30 and connected to the first insulating layer 22.

In an exemplary embodiment, the first insulating layer 22 can connect the entirety of the diaphragm structure layer and the second electrode 28 layer with the driving circuit layer 10, and can wrap the first electrode 21, preventing leakage of the first electrode 21.

In an exemplary embodiment, the diaphragm structure layer includes a first diaphragm layer 24, a second diaphragm layer 26 disposed on a side of the first diaphragm layer 24 away from the substrate 30, and a third diaphragm layer 27 disposed on a side of the second diaphragm layer 26 away from the substrate 30; a gap is formed between the surface of the support column 25, which is far away from the substrate 30, and the surface of the first vibrating diaphragm layer 24, which is close to the substrate 30, so that the vibrating diaphragm structure layer still has space for vibration, and the normal operation of the vibrating diaphragm structure layer is not affected by the arrangement of the support column 25, so that the vibration performance of the ultrasonic transducer substrate is ensured.

In exemplary embodiments, the gap may be about the height ofTo->The height of the gap is the dimension in a direction perpendicular to the substrate 30. For example, the height of the gap may be about +.>Left and right.

In an exemplary embodiment, the support column 25 may have a cross-sectional shape of, but not limited to, a column shape or a trapezoid shape in a direction perpendicular to the substrate 30, and a first width W1 of a side surface of the support column 25 away from the substrate 30 may be less than or equal to a second width W2 of a side surface of the support column 25 close to the substrate 30, the first width W1 and the second width W2 being dimensions parallel to the direction of the substrate 30, as shown in fig. 20. Because of the small area of the support pillars 25, the effect of the charge on the support pillars 25 is negligible.

In an exemplary embodiment, the ratio of the first width W1 to the second width W2 may range from about 0.5 to about 0.8. For example, the ratio of the first width W1 to the second width W2 may be about 0.65.

In an exemplary embodiment, the cross-sectional shape of the support column 25 in a direction parallel to the substrate 30 may be, but is not limited to, circular, elliptical, rectangular, pentagonal, or hexagonal.

In an exemplary embodiment, at least one first via 100 is disposed on the first diaphragm layer 24, and the second diaphragm layer 26 is capable of filling the first via 100. In the embodiment of the present application, two first vias 100 may be disposed in the cross-sectional direction shown in fig. 2. The two first vias 100 are disposed on two sides of the first electrode 21, respectively, and the front projection of the first via 100 on the substrate 30 does not overlap with the front projection of the first electrode 21 on the substrate 30. Because the first electrode 21 is arranged corresponding to the cavity 201, the above arrangement of the first via hole 100 can be far away from the main vibration area of the diaphragm structure layer, so that the influence of the first via hole 100 on the vibration parameter of the diaphragm structure layer is reduced, and the diaphragm structure layer is prevented from cracking at the position of the first via hole 100 due to vibration.

In an exemplary embodiment, the front projection of the first via 100 onto the substrate 30 does not overlap with the front projection of the second electrode 28 onto the substrate 30.

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

An exemplary description is given below of the process of manufacturing an ultrasonic transducer. The patterning process disclosed by the application comprises the steps of depositing a film layer, coating photoresist on the film layer, mask exposure, development, etching, stripping photoresist and the like for metal materials, inorganic materials or transparent conductive materials, and coating organic materials, mask exposure, development and the like for organic materials. The deposition can be any one or more of sputtering, vapor deposition and chemical vapor deposition, the coating can be any one or more of spraying, spin coating and ink jet printing, and the etching can be any one or more of dry etching and wet etching, so that the application is not limited. "film" refers to a layer of film formed by depositing, coating, or other process of a material on a substrate 30. The "film" may also be referred to as a "layer" if the "film" does not require a patterning process throughout the fabrication process. If the "thin film" requires a patterning process throughout the fabrication process, it is referred to as a "thin film" prior to the patterning process, and as a "layer" after the patterning process. The "layer" after the patterning process includes at least one "pattern". The application relates to a method for forming a display substrate, which comprises the steps of forming a film layer on a substrate, forming a first layer of the film layer, forming a second layer of the film layer, and forming a third layer of the film layer. In an exemplary embodiment of the present application, "the front projection of B is within the range of the front projection of a" or "the front projection of a includes the front projection of B" means that the boundary of the front projection of B falls within the boundary range of the front projection of a or the boundary of the front projection of a overlaps with the boundary of the front projection of B.

The process of manufacturing the ultrasonic transducer in the exemplary embodiment of the present application may include the following operations.

1. The driving circuit layer 10 is prepared. In an exemplary embodiment, the driving circuit layer 10 may include a first transistor 11, a second transistor 12, and a capacitor 13, as shown in fig. 4. The driving circuit layer 10 may be prepared by a conventional process, and will not be described again.

2. Preparing an ultrasonic transducer substrate:

(1) The first electrode 21 layer pattern is formed. In an exemplary embodiment, forming the first electrode 21 layer pattern may include: on the substrate 30 on which the foregoing pattern is formed, a first conductive film is deposited, and the first conductive film is patterned by a patterning process to form a first electrode 21 layer pattern disposed on a side of the driving circuit layer 10 remote from the substrate 30, and 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, as shown in fig. 5.

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

In an exemplary embodiment, the thickness of the first electrode 21 may be aboutTo->For example, the thickness of the first electrode 21 may be about +.>Left and right.

(2) The sacrificial layer 23 is patterned. In an exemplary embodiment, forming the sacrificial layer 23 pattern may include:

a first insulating film and a sacrificial film are sequentially deposited on the substrate 30 on which the foregoing patterns are formed, the sacrificial film is patterned by a patterning process to form a first insulating layer 22 disposed on a side of the first electrode 21 where the layer pattern is away from the substrate 30 and a sacrificial layer 23 disposed on a side of the first insulating layer 22 where the layer pattern is away from the substrate 30, as shown in fig. 6 to 8, fig. 6 is a cross-sectional view of the cross-sectional position A-A in fig. 1, and fig. 7 is a cross-sectional view of the cross-sectional position B-B in fig. 1. The sacrificial layer 23 includes at least a sacrificial portion 231 and a sacrificial connection portion 232. In an exemplary embodiment, the number of the sacrificial parts 231 is plural and corresponds to the first electrodes 21 one by one. Four sacrificial connection portions 232 are correspondingly connected to each sacrificial portion 231. The four sacrificial connection portions 232 are uniformly distributed around the circumference of the sacrificial portion 231.

In an exemplary embodiment, the material of the first insulating layer 22 may include, but is not limited to, silicon nitride (SiNx), silicon oxide (SiOx), or the like, may be a single-layer structure, or may be a multi-layer structure. The first insulating layer 22 may be referred to as a Buffer (Buffer) layer, and may improve the resistance to water and oxygen of the first electrode 21 layer pattern, preventing water and oxygen from being immersed downward from the first electrode 21 layer pattern and the driving circuit layer 10 from affecting the electrical characteristics thereof.

In an exemplary embodiment, the thickness of the first insulating layer 22 may be aboutTo->For example, the thickness of the first insulating layer 22 may be about +.>Left and right.

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

In an exemplary embodiment, the thickness of the sacrificial layer 23 may be aboutFor example, the thickness of the sacrificial layer 23 may be about +.>Left and right.

(3) The first diaphragm layer 24 is patterned. In an exemplary embodiment, forming the first diaphragm layer 24 pattern may include:

the first vibration film is deposited on the substrate 30 with the pattern formed, the first vibration film is patterned by a patterning process to form a first vibration film layer 24 disposed on one side of the sacrificial layer 23 far from the substrate 30, at least a first via hole 100 is disposed on the first vibration film layer 24, the first vibration film in the first via hole 100 is etched away to expose the surface of the sacrificial layer 23, as shown in fig. 9 and 10, fig. 9 is a cross-sectional view of A-A in fig. 1 toward a cross-sectional position, and fig. 10 is a cross-sectional view of B-B in fig. 1 toward a cross-sectional position. In an exemplary embodiment, each first electrode 21 corresponds to four first vias 100. Four first vias 100 are disposed in the circumferential direction of the first electrode 21, and the front projection of the first vias 100 on the substrate 30 does not overlap with the front projection of the first electrode 21 on the substrate 30, and at least partially overlaps with the front projection of the sacrificial connection 232 on the substrate 30 to enable exposure of the sacrificial connection 232.

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

In an exemplary embodiment, the first diaphragm layer 24 may have a thickness of aboutFor example, the thickness of the transparent layer may be about +.>Left and right.

(4) The cavity 200 is patterned. In an exemplary embodiment, forming the cavity 200 pattern may include: with the first via hole 100, the sacrificial layer 23 is removed by a wet etching process, a plurality of cavities 200 are formed between the first insulating layer 22 and the first diaphragm layer 24, and the cavities 200 include cavity portions 201 formed by removing the sacrificial portions 231 and cavity connection portions 202 formed by removing the sacrificial connection portions 232. The cavity portion 201 communicates with the cavity connecting portion 202. The first via 100 communicates with the cavity connection 202, as shown in fig. 11 and 12, fig. 11 is a cross-sectional view taken along A-A in fig. 1, and fig. 12 is a cross-sectional view taken along B-B in fig. 1.

In an exemplary embodiment, the thickness of the cavity 200 corresponds to the thickness of the sacrificial layer 23. For example, the thickness of the cavity 200 may be aboutLeft and right.

(5) Forming a pattern of support structures. In an exemplary embodiment, forming the support structure pattern may include:

on the substrate 30 having the foregoing pattern formed, a support film is first coated, and the support film is subjected to a pre-baking process after entering the cavity 200 by capillary action of the first via hole 100.

The support film within the cavity 200 is then patterned by patterning to form a transitional structure, as shown in fig. 13 and 14, fig. 13 being a cross-sectional view of the A-A cross-sectional position of fig. 1, and fig. 14 being a cross-sectional view of the B-B cross-sectional position of fig. 1.

In an exemplary embodiment, the transition structure may include at least one transition post 25a, the transition post 25a height H1 conforming to the thickness of the cavity 200.

A post-bake process is then performed to shrink the transitional structure to form a support structure disposed on a side of the first insulating layer 22 away from the substrate 30, as shown in fig. 15 and 16, where fig. 15 is a cross-sectional view of the cross-sectional position A-A in fig. 1, and fig. 16 is a cross-sectional view of the cross-sectional position B-B in fig. 1.

In an exemplary embodiment, as shown in fig. 20, the support structure may include at least one support post 25, the support post 25 having a height H2 that is less than the thickness of the cavity 200, such that a gap is formed between the support post 25 and the first diaphragm layer 24 without affecting the operation of the first diaphragm layer 24. At the same time, the effect on charge is negligible due to the smaller area of the support pillars 25.

In an exemplary embodiment, the front projection of the support post 25 onto the substrate 30 at least partially overlaps the front projection of the first electrode 21 onto the substrate 30.

In an exemplary embodiment, the support columns 25 may have a circular, oval, rectangular, pentagonal, or hexagonal cross-sectional shape in a direction parallel to the substrate 30.

In an exemplary embodiment, the support column 25 may have a cylindrical or trapezoidal cross-sectional shape in a direction perpendicular to the substrate 30, and a first width W1 of a side surface of the support column 25 away from the substrate 30 may be less than or equal to a second width W2 of a side surface of the support column 25 close to the substrate 30, the first width W1 and the second width W2 being dimensions parallel to the direction of the substrate 30, as shown in fig. 20.

In an exemplary embodiment, the support film may be a film having low viscosity, easy coating, good insulation, and high elastic recovery among ultraviolet positive and negative photoresist, deep ultraviolet photoresist, X-ray photoresist, electron beam photoresist, or ion beam photoresist.

(6) A second electrode 28 layer pattern is formed. In an exemplary embodiment, forming the second electrode 28 layer pattern may include:

a second vibration film is deposited on the substrate 30 with the patterns, a second vibration film 26 is formed to cover the side, away from the substrate 30, of the first vibration film 24, then a third vibration film is coated on the side, away from the substrate 30, of the second vibration film 26, a third vibration film 27 is formed on the side, away from the substrate 30, of the second vibration film 26 after curing treatment, then a second conductive film is deposited on the side, away from the substrate 30, of the third vibration film 27, the second conductive film is patterned through a patterning process, a second electrode 28 layer pattern is formed on the side, away from the substrate 30, of the third vibration film 27, the second electrode 28 layer pattern may include at least one second electrode 28, as shown in fig. 17 and 18, fig. 17 is a cross-sectional view of the a-section position in fig. 1, and fig. 18 is a cross-sectional view of the B-section position in fig. 1. The second electrode 28 may be electrically connected to the driving voltage line.

In an exemplary embodiment, the material of the second diaphragm layer 26 may include, but is not limited to, any one or more of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), and may be a single layer, a multi-layer, or a composite layer. The second diaphragm layer 26 may be referred to as a first Passivation (PVX) layer.

In an exemplary embodiment, the secondThe thickness of the diaphragm layer 26 may be aboutFor example, the thickness of the second diaphragm layer 26 may be about +.>Left and right.

In an exemplary embodiment, the material of the third diaphragm layer 27 is an organic material, for example, a Resin (Resin) or the like. May be a single layer, multiple layers or a composite layer.

The third diaphragm layer 27 may be referred to as a flat (PLN) layer or a Resin (Resin) layer.

In an exemplary embodiment, the thickness of the third diaphragm layer 27 may be aboutFor example, the thickness of the third diaphragm layer 27 may be about +.>Left and right.

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

In an exemplary embodiment, the thickness of the second electrode 28 may be aboutTo->For example, the thickness of the second electrode 28 may be about +.>Left and right.

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

(7) A second insulating layer 29 is formed. In an exemplary embodiment, forming the second insulating layer 29 may include:

a second insulating film is deposited on the substrate 30 on which the foregoing pattern is formed, and a second insulating layer 29 is formed to cover the pattern of the second electrode 28 layer, as shown in fig. 19, fig. 19 being a sectional view of the cross-sectional position A-A in fig. 1.

In an exemplary embodiment, the material of the second insulating layer 29 may include, but is not limited to, any one or more of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiON), and may be a single layer, a multi-layer, or a composite layer.

The second insulating layer 29 may be referred to as a second Passivation (PVX) layer.

In an exemplary embodiment, the thickness of the second insulating layer 29 may be aboutTo->For example, the thickness of the second insulating layer 29 may be about +.>Left and right.

The structure of the ultrasonic transducer according to the exemplary embodiment of the present application and the manufacturing process thereof are merely one exemplary illustration. In exemplary embodiments, the corresponding structures may be altered and patterning processes may be increased or decreased as desired.

The application also provides a preparation method of the ultrasonic transducer substrate. In an exemplary embodiment, a method of manufacturing an ultrasonic transducer substrate may include:

forming a first electrode 21 layer on a substrate 30;

forming a diaphragm structure layer on the first electrode 21 layer, arranging a cavity 200 between the first electrode 21 layer and the diaphragm structure layer, arranging at least one support column 25 in the cavity 200, wherein the cavity 200 has a first height H1, the support column 25 has a second height H2, the second height H2 is smaller than the first height H1, and the first height H1 and the second height H2 are vertical to the dimension of the substrate 30;

a second electrode 28 layer is formed on the side of the diaphragm structure layer remote from the substrate 30.

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

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;

a second diaphragm layer 26 and a third diaphragm layer 27 are sequentially formed on the first diaphragm layer 24.

In an exemplary embodiment, the first diaphragm layer 24 is formed on the first electrode 21 layer, the cavity 200 is formed between the first electrode 21 layer and the first diaphragm layer 24, and at least one support pillar 25 is formed in the cavity 200, and may include:

forming a sacrificial film on the first electrode 21 layer, forming a sacrificial layer 23 through patterning, the sacrificial layer 23 including at least a sacrificial portion 231 and a sacrificial connection portion 232;

forming a first diaphragm layer 24 on the sacrificial layer 23, wherein at least one first via hole 100 is arranged on the first diaphragm layer 24, and the orthographic projection of the first via hole 100 on the substrate 30 at least partially overlaps with the orthographic projection of the sacrificial connection portion 232 on the substrate 30;

removing the sacrificial layer 23 by using an etching process using the first via hole 100, and forming a cavity 200 between the first electrode 21 layer and the first diaphragm layer 24;

at least one support column 25 is formed within the cavity 200.

In an exemplary embodiment, forming at least one support post 25 within the cavity 200 may include:

filling the cavity 200 with a support film;

patterning the support film by a patterning process to form at least one support column 25a, the support column 25a having a second height H2;

the support column 25 is formed by shrinking the support column 25a by a post-baking process.

In an exemplary embodiment, filling the cavity 200 with a support film may include

A support film is coated on the first diaphragm layer 24 such that the support film enters the cavity 200 by capillary action of the first via 100.

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

The embodiment of the application also provides an ultrasonic transducer, which comprises the ultrasonic transducer substrate of the embodiment. The ultrasonic transducer can be used for fingerprint identification, so that functions such as fingerprint unlocking and the like are realized. Because the reflection intensity of the ridges and the valleys on the surface of the finger on the ultrasonic signals is different, the ultrasonic energy reflected by the ridges and the valleys of the finger is different, and the difference of the energy is converted into the difference of electric signals, so that the imaging of the ridges and the valleys of the fingerprint can be performed, and further fingerprint identification is performed. The fingerprint identification device can be arranged in any product or component with fingerprint identification function such as a mobile phone, a tablet computer, access control equipment, a display, a notebook computer, a digital photo frame or a navigator.

Although the embodiments of the present application are described above, the embodiments are only used for facilitating understanding of the present application, and are not intended to limit the present application. Any person skilled in the art can make any modification and variation in form and detail without departing from the spirit and scope of the present disclosure, but the scope of the present disclosure is to be determined by the appended claims.

Claims (13)

1. The ultrasonic transducer substrate is characterized by comprising a first electrode layer arranged on a substrate, a vibrating diaphragm structural layer arranged on one side of the first electrode layer away from the substrate, and a second electrode layer arranged on one side of the vibrating diaphragm structural layer away from the substrate, wherein a cavity is arranged between the first electrode layer and the vibrating diaphragm structural layer, at least one supporting column is arranged in the cavity, the cavity is provided with a first height, the supporting column is provided with a second height, the second height is smaller than the first height, and the first height and the second height are perpendicular to the dimension in the direction of the substrate.

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 ultrasound transducer substrate according to claim 1, wherein the first electrode layer comprises at least one first electrode and the second electrode layer comprises at least one second electrode, an orthographic projection of the second electrode on the substrate at least partially overlapping an orthographic projection of the first electrode on the substrate, an orthographic projection of the support post on the substrate at least partially overlapping an orthographic projection of the first electrode on the substrate.

4. The ultrasonic transducer substrate of claim 3, wherein the first electrode layer further comprises a first insulating layer disposed on a side of the first electrode remote from the base, and the support posts are disposed on a side of the first insulating layer remote from the base and connected to the first insulating layer.

5. The ultrasonic transducer substrate of claim 1, wherein the diaphragm structure layer comprises a first diaphragm layer, a second diaphragm layer disposed on a side of the first diaphragm layer away from the base, and a third diaphragm layer disposed on a side of the second diaphragm layer away from the base; and a gap is formed between the surface of the support column far away from one side of the substrate and the surface of the first vibrating diaphragm layer close to one side of the substrate.

6. The ultrasonic transducer substrate of claim 5, wherein the gap has a height ofTo the point ofThe height of the gap is the dimension in a direction perpendicular to the substrate.

7. The ultrasonic transducer substrate of claim 5, wherein a first width of the support posts away from the base-side surface can be less than or equal to a second width of the support posts near the base-side surface, the first and second widths being dimensions parallel to the base direction.

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 has at least one first via disposed thereon, wherein the orthographic projection of the first via on the substrate does not overlap with the orthographic projection of the first electrode on the substrate, and wherein the orthographic projection of the first via on the substrate does not overlap with the orthographic projection of the second electrode on the substrate.

10. The ultrasonic transducer substrate of claim 9, wherein the first via is filled with the second diaphragm layer.

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

12. The ultrasonic transducer substrate of claim 3, wherein the second electrode layer further comprises a second insulating layer disposed on a side of the second electrode remote from the base.

13. An ultrasound transducer comprising an ultrasound transducer substrate according to any of claims 1 to 12.