Ultrasonic transducer and manufacturing method therefor

Abstract

An ultrasonic transducer and a manufacturing method therefor. The ultrasonic transducer successively comprises, from bottom to top, an IC substrate, an element array layer and an insulating layer; the element array layer comprises a plurality of transducer units; each transducer unit comprises an upper electrode layer and a piezoelectric material layer; by means of metal protrusions on the upper electrode layers, the transducer units are soldered to the IC substrate; the insulating layer comprises a plurality of vibration structure units. In the present invention, the transducer units are mounted upside down, so that the upper electrode layers having the metal protrusions are inverted to be in direct contact with and soldered to the IC substrate below, thereby achieving a firm structure, a simple process, and low cost, ensuring the shortest signal transmission path and lower interference and attenuation, and greatly improving signal transmission reliability and signal quality.

Description

Ultrasonic transducer and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 29, 2024, with application number 202410384567.7 and invention name “An ultrasonic transducer and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of ultrasonic transducers, and in particular to an ultrasonic transducer and a preparation method thereof. Background Art

[0003] With the development of technology, ultrasonic transducers are increasingly being used in various fields. Currently, the technologies used to connect electrodes in miniaturized two-dimensional ultrasonic transducers are mainly wire bonding or through-silicon via (TSV).

[0004] Wire bonding is the process of connecting the transducer array elements to the connector terminals using gold wire at the electrode ends of the manufactured miniaturized two-dimensional array ultrasonic transducer. The positive and negative electrodes of the transducer are respectively connected to the bonding wires from the upper and lower surfaces. The Through Silicon Via (TSV) process uses dry or wet etching methods to lead the positive and negative electrodes of the ultrasonic transducer array elements to the same surface, and uses through holes filled with conductive material to achieve electrical connection with the underlying circuit board.

[0005] However, the wire bonding process requires the introduction of signal transmission lines. The characteristic impedance and signal attenuation of the signal transmission lines themselves will bring additional signal interference. The through-silicon via process is not only complex and costly, but also requires a large amount of welding to achieve the connection between the electrode and the through-hole, which is prone to misalignment, short circuits, cold solder joints, etc., thereby reducing the yield of the finished product.

[0006] Therefore, how to improve the reliability and quality of signal transmission while ensuring low cost and high yield is an urgent problem to be solved by those skilled in the art.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to provide an ultrasonic transducer and a method for preparing the same, so as to solve the problem in the prior art that it is impossible to ensure high signal transmission reliability and signal quality while ensuring low cost and high yield.

[0009] In order to solve the above technical problems, the present invention provides an ultrasonic transducer, which comprises, from bottom to top, an IC substrate, a component array layer and an insulating layer;

[0010] The element array layer includes a plurality of transducer units;

[0011] The transducer unit includes an upper electrode layer and a piezoelectric material layer;

[0012] The transducer unit is welded to the IC substrate via the metal protrusions on the upper electrode layer;

[0013] The insulating layer includes a plurality of vibration structure units.

[0014] Optionally, in the ultrasonic transducer, the vibration structure unit is provided with a back cavity groove in a direction perpendicular to the element array layer;

[0015] The diameter of the back cavity groove gradually decreases from the opening to the bottom of the groove.

[0016] Optionally, the ultrasonic transducer further includes a porous heat dissipation substrate;

[0017] The surface of the IC substrate away from the metal protrusion is fixedly connected to the porous heat dissipation substrate.

[0018] Optionally, in the ultrasonic transducer, the IC substrate is an ASIC substrate.

[0019] Optionally, the ultrasonic transducer further includes electronic insulating glue;

[0020] The electronic insulating glue is filled between adjacent transducer units.

[0021] Optionally, the ultrasonic transducer further includes an acoustic impedance matching layer;

[0022] The acoustic impedance matching layer at least covers the outer surface of the insulating layer.

[0023] Optionally, in the ultrasonic transducer, the acoustic impedance matching layer further includes a conductive adhesive layer;

[0024] The insulating layer insulates the element array layer from the conductive adhesive layer.

[0025] Optionally, in the ultrasonic transducer, the lower electrodes of the plurality of transducer units are connected to the IC substrate via at least one of a coaxial cable, gold wire bonding, and through-silicon via direct connection.

[0026] A method for preparing an ultrasonic transducer, comprising:

[0027] A piezoelectric material layer is provided on the insulating layer, wherein the insulating layer includes a plurality of vibration structural units;

[0028] Plate an upper electrode layer on a first surface of the piezoelectric material layer, where the first surface is a surface of the piezoelectric material layer away from the insulating layer;

[0029] Cutting the first surface coated with the upper electrode layer to obtain a plurality of array elements;

[0030] By implanting metal protrusions on the array elements, the array elements are converted into transducer units to obtain an element array layer;

[0031] The element array layer is welded to the IC substrate through the metal protrusions.

[0032] Optionally, in the method for preparing the ultrasonic transducer, the metal protrusion is connected to the IC substrate by reflow soldering.

[0033] The ultrasonic transducer provided by the present invention comprises, from bottom to top, an IC substrate, an element array layer, and an insulating layer; the element array layer comprises a plurality of transducer units; the transducer units comprise an upper electrode layer and a piezoelectric material layer; the transducer units are soldered to the IC substrate via metal protrusions on the upper electrode layer; and the insulating layer comprises a plurality of vibration structure units. In the present invention, the transducer unit is flipped upside down, and the upper electrode layer with the metal protrusions is in turn soldered in direct contact with the underlying IC substrate, resulting in a strong structure, simple process, and low cost. At the same time, it ensures the shortest signal transmission path, minimizes interference, and reduces attenuation, thereby greatly improving signal transmission reliability and signal quality. The present invention also provides a method for preparing an ultrasonic transducer having the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] FIG1 is a schematic structural diagram of a specific embodiment of an ultrasonic transducer provided by the present invention;

[0036] FIG2 is a schematic structural diagram of a specific embodiment of an ultrasonic transducer provided by the present invention;

[0037] FIG3 is a schematic flow chart of a specific embodiment of a method for preparing an ultrasonic transducer provided by the present invention;

[0038] FIG4 is a process structure diagram of a specific embodiment of the method for preparing an ultrasonic transducer provided by the present invention;

[0039] FIG5 is a schematic diagram of a partial structure of a specific embodiment of the ultrasonic transducer provided by the present invention.

[0040] In the figure, it includes 100-IC substrate, 200-element array layer, 300-insulating layer, 210-transducer unit, 211-piezoelectric material layer, 212-upper electrode layer, 213-metal protrusion, 214-lower electrode layer, 310-vibration structure unit, and 400-substrate. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0042] The core of the present invention is to provide an ultrasonic transducer, a structural diagram of a specific embodiment of which is shown in FIG1 , referred to as specific embodiment 1, which includes, from bottom to top, an IC (Integrated Circuit) substrate 100 , a component array layer 200 and an insulating layer 300 .

[0043] The element array layer 200 includes a plurality of transducer units 210 .

[0044] The transducer unit 210 includes an upper electrode layer 212 , a piezoelectric material layer 211 , and a lower electrode layer (not shown in FIG. 1 ).

[0045] The transducer unit 210 is connected to the IC substrate 100 by welding via the metal protrusions 213 on the upper electrode layer 212 .

[0046] The insulating layer 300 includes a plurality of vibration structure units 310 .

[0047] Of course, the transducer unit 210 needs to be connected to the circuit where the IC substrate 100 is located to obtain the corresponding signal, so it is connected to the external circuit through the upper electrode and the lower electrode. Since the transducer unit 210 is inverted in the present invention, the upper electrode layer 212 is instead at the bottom. Please refer to Figure 5, which shows a local enlarged schematic diagram of the ultrasonic transducer, in which the upper electrode layer 212 (generally the positive electrode) is in direct contact with the IC substrate 100. Correspondingly, the lower electrode layer 214 in the figure is connected to the substrate 400 (usually a PCB substrate) where the IC substrate 100 is located through a cable.

[0048] The ultrasonic transducer of the present invention may be a two-dimensional array ultrasonic transducer, or other types of two-dimensional focused ultrasonic transducers, such as 1.25D, 1.5D and 1.75D arrays, or a one-dimensional linear array ultrasonic transducer array.

[0049] As a specific embodiment, the piezoelectric material layer 211 can be at least one of a piezoelectric ceramic layer, a piezoelectric single crystal layer, a piezoelectric composite material layer, a silicon-based CMUT (Capacitive Micromachined Ultrasonic Transducer) layer, and a silicon-based PMUT (Piezoelectric Micromachined Ultrasonic Transducer) layer. Of course, it can also be further combined with composite ceramic technology to form a 1-3 type composite material structure by molding the piezoelectric ceramic raw materials. The selection can be made according to actual conditions. The insulating layer 300 can also be an insulating layer based on CSOI (Cavity-Silicon On Insulator, cavity SOI), which can also be selected according to actual conditions. The present invention is not limited here.

[0050] As a preferred embodiment, the lower electrodes of multiple transducer units 210 are connected to the IC substrate 100 via at least one of a coaxial cable, gold wire bonding, or through-silicon vias. The lower electrodes of multiple transducer units 210 are interconnected and directly connected to the IC substrate 100 via at least one of a coaxial cable, gold wire bonding, or through-silicon vias. This greatly simplifies the device's circuit structure, reduces production costs, and improves the device's operational stability. In one specific embodiment, the lower electrode is connected to the ground electrode connection point of the IC substrate 100. By controlling the electrical signals of the upper electrodes of different transducer units, the voltage difference between the upper and lower electrodes of the corresponding transducer units can be controlled, thereby controlling the output of ultrasonic energy.

[0051] In another embodiment of the present application, the lower electrodes of different transducer units may also be separated from each other and respectively connected to different electrical connection points of the IC substrate to achieve independent, more complex but more precise control.

[0052] As a specific embodiment, it also includes a porous heat dissipation substrate 400;

[0053] The surface of the IC substrate 100 away from the metal protrusions 213 is fixedly connected to the porous heat dissipation substrate 400 .

[0054] The ultrasonic transducer can be integrated into other structures, and the integrated structure can provide a substrate 400 for the ultrasonic transducer to be placed. In this specific embodiment, the substrate 400 on which the IC substrate 100 is located is a porous heat dissipation substrate 400, that is, there are multiple heat dissipation holes on the substrate 400, which can greatly improve the heat dissipation efficiency, allowing the ultrasonic transducer to be maintained at a suitable operating temperature for a long time, thereby extending the continuous working time of the ultrasonic transducer.

[0055] Preferably, the IC substrate 100 is an ASIC (Application Specific Integrated Circuit) substrate. ASIC substrate 100 offers greater customization potential and higher access efficiency, is suitable for simultaneous multi-point access, easily provides very high bandwidth, and is easily scalable in performance. It is not easily limited by other hardware in the circuit, further broadening the applicability of ultrasonic transducers.

[0056] In addition, electronic insulating glue is also included; the electronic insulating glue is filled between adjacent transducer units 210 .

[0057] Of course, the multiple transducer units 210 in the element array layer 200 should be controlled independently. Therefore, in order to avoid short circuits between adjacent transducer units 210 due to factors such as vibration during operation (mainly short circuits of the upper electrodes), electronic insulating glue is filled between adjacent transducer units 210 in this preferred embodiment. Of course, the electronic insulating glue can be low-temperature electronic insulating glue, which remains solid at the normal operating temperature of the ultrasonic transducer.

[0058] Of course, to ensure insulation between adjacent transducer units 210, electronic insulating adhesive can be used to completely fill the gap between the element array layer 200 and the IC substrate 100, thereby ensuring that the gaps between the transducer units 210 are completely filled with the electronic insulating adhesive. Of course, other methods can also be used to ensure insulation between adjacent transducer units 210, such as by reserving sufficient space and using a non-contact method to ensure insulation. The present invention is not limited to this and can be selected according to actual needs.

[0059] As a specific embodiment, it also includes an acoustic impedance matching layer;

[0060] The acoustic impedance matching layer at least covers the outer surface of the insulating layer 300 .

[0061] The acoustic impedance matching layer matches the acoustic impedance of the object of the ultrasonic transducer so as to conduct the vibration energy with maximum efficiency.

[0062] This specific embodiment further adds an acoustic impedance matching layer to the ultrasonic transducer to match the surface to which the ultrasonic transducer will be attached. Furthermore, this preferred embodiment defines the outermost layer of the acoustic impedance matching layer as at least one of an epoxy resin layer and a vulcanized rubber layer. Epoxy resin layers and vulcanized rubber layers have improved biocompatibility and are suitable for a wide range of applications of ultrasonic transducers within the human body, further broadening the scope of application of ultrasonic transducers. Furthermore, the acoustic impedance matching layer also includes a conductive adhesive layer.

[0063] The insulating layer 300 insulates the device array layer 200 from the conductive adhesive layer.

[0064] The insulating layer 300 isolates the conductive adhesive layer from the lower electrode layer 214 of the element array layer 200, preventing the risk of short circuits caused by contact between the two, particularly during vibration of the insulating layer 300. Furthermore, a potential difference is created between the lower electrode layer 214 and the conductive adhesive layer, amplifying the vibration effect and thereby increasing ultrasonic output energy. The conductive adhesive layer can be a conductive silver adhesive layer or a graphite powder adhesive layer.

[0065] Preferably, the conductive adhesive layer is directly sprayed on the surface of the insulating layer 300. In other words, the conductive adhesive layer is the layer closest to the insulating layer 300 in the acoustic impedance matching layer, so as to further improve the ultrasonic sensitivity effect and output energy.

[0066] When the conductive adhesive layer is sprayed onto the surface of the insulating layer 300 using a spraying process, some of the conductive adhesive may pass through the edges and reach the component array layer 200 below the insulating layer 300. Without prior treatment, there is a risk of short circuit. To address this issue, the above-mentioned embodiment uses electronic insulating adhesive to fill and insulate the component array layer, thereby preventing short circuits between the conductive adhesive layer and the component array layer 200. Alternatively, the edge can be cut away through edge cutting to prevent short circuits between the conductive adhesive layer and the component array layer.

[0067] In one embodiment of the present invention, an oxide layer is further provided on the surface of the insulating layer 300 near the element array layer 200. This structure can further improve the electrical insulation performance of the insulating layer 300. Specifically, the oxide layer can be a layer structure obtained by oxidation treatment on the surface of the original insulating layer 300. When the original insulating layer 300 is a silicon layer, the oxide layer is a silicon oxide layer, specifically obtained by oxidation treatment on the surface of a silicon wafer.

[0068] A specific embodiment of an ultrasonic transducer is given below. In this specific embodiment, a semiconductor FCBGA (Flip Chip Ball Grid Array) flip-chip package is used to grow a bump (also known as the metal protrusion 213 mentioned above) on a CSOI or piezoelectric ceramic-piezoelectric single crystal. The bump is a copper column or a solder ball. The spacing between each array element of the phased array transducer is related to the sound beam deflection angle of the phased imaging, and theoretically needs to satisfy the following formula (1): Pitch ≤ 1 / 2λ; (1)

[0069] Here, c is the speed of sound within the object being acted upon. For example, if the ultrasonic transducer is for medical or cosmetic purposes, it is the speed of sound corresponding to human tissue. f is the center frequency of the corresponding transmission frequency, and λ is the wavelength, approximately equal to c / f. In practical applications, this spacing is set between 0.5λ and 1λ to accommodate process requirements. For broadband transducers, the element spacing can be appropriately increased, with a value of 0.7 to 0.9 times the wavelength being appropriate. In intracardiac ultrasound applications, the center frequency is approximately 6.5MHz. Calculations indicate that the size of the copper pillars or individual elements is less than 200µm. Using manual wire bonding or traditional FPC hot pressing processes can easily lead to cold solder joints, misalignment, and short circuits. Furthermore, the solder joints themselves can introduce additional interference signals. Furthermore, a signal transmission cable is required, and the characteristic impedance and attenuation of the cable itself can also introduce additional interference signals.

[0070] In this invention, a flip-chip process is used to grow metal bumps on the front surface (top electrode) of the transducer unit. The array element is then reflow-soldered to electrically connect the array element to the underlying IC. This reduces the size of the solder joints and increases the capacitance required for signal transmission, thereby reducing signal attenuation, improving signal quality, and significantly enhancing signal transmission reliability.

[0071] The ultrasonic transducer provided by the present invention comprises, from bottom to top, an IC substrate 100, an element array layer 200, and an insulating layer 300. The element array layer 200 includes multiple transducer units 210. The transducer units 210 include an upper electrode layer 212 and a piezoelectric material layer 211. The transducer units 210 are soldered to the IC substrate 100 via metal protrusions 213 on the upper electrode layer 212. The insulating layer 300 includes multiple vibration structure units 310. In the present invention, the transducer units 210 are flipped upside down, with the upper electrode layer 212 with metal protrusions 213 inverted and then soldered directly to the underlying IC substrate 100. This results in a robust structure, simple process, and low cost. It also ensures the shortest signal transmission path, minimizes interference, and reduces attenuation, significantly improving signal transmission reliability and quality.

[0072] On the basis of the first embodiment, the vibration structure unit 310 is further improved to obtain the second embodiment, the corresponding structural diagram of which is shown in FIG2 , which includes, from bottom to top, an IC substrate 100 , a component array layer 200 , and an insulating layer 300 ;

[0073] The element array layer 200 includes a plurality of transducer units 210;

[0074] The transducer unit 210 includes an upper electrode layer 212 and a piezoelectric material layer 211;

[0075] The transducer unit 210 is welded to the IC substrate 100 via the metal protrusions 213 on the upper electrode layer 212;

[0076] The insulating layer 300 includes a plurality of vibration structure units 310;

[0077] The vibration structure unit 310 is provided with a back cavity groove in a direction perpendicular to the element array layer 200;

[0078] The diameter of the back cavity groove gradually decreases from the opening to the bottom of the groove.

[0079] The difference between this specific embodiment and the above specific embodiment is that this specific embodiment defines the structure of the back cavity groove on the back of the vibration structure unit 310, and the remaining structures refer to the description of the above specific embodiment and will not be repeated in this specific embodiment.

[0080] In this preferred embodiment, the vibration structure unit 310 is further limited to a back cavity groove, and the diameter of the back cavity groove gradually decreases from the opening to the bottom of the groove. Referring to Figure 2, the cross-section of the side wall of the back cavity groove in Figure 2 is a right-angled trapezoid. The back cavity groove structure with a diameter gradually increasing from the bottom to the outside can make the energy of the vibration structure unit 310 more concentrated, avoid excessive energy being consumed by the ultrasonic transducer, increase the sensitivity of the signal, and further ensure the singleness of the vibration mode without interference, thereby improving the final output vibration to meet the relevant expectations.

[0081] Furthermore, the primary vibrating structure of the vibration structure unit 310 is the thin film at the bottom of the groove. This thin film can be obtained by controlling the etching depth during etching of the insulating layer 300 to avoid penetrating the insulating layer. Compared to a straight-cylinder etched structure (i.e., the groove diameter is essentially the same from the opening to the bottom), the angle between the sidewalls of the gradually decreasing groove and the bottom is an obtuse angle. When the thin film at the bottom of the groove vibrates, the structural stress at this angle is low, allowing the film to have a larger amplitude, thereby increasing the output of ultrasonic energy. Furthermore, compared to a solution where the angle between the sidewalls of the groove and the bottom is a right angle, the gradually decreasing groove structure can improve the vibration mode of a single element during vibration.

[0082] The side wall cross-section of the vibration structure unit 310 may be a trapezoidal shape or an irregular shape. For example, the side wall may be an arc surface. The selection may be made according to actual conditions and is not limited in the present invention.

[0083] In this embodiment, the groove bottom and the groove wall are made of the same material and are etched from a single wafer. In other embodiments of the present invention, the thin film at the groove bottom can also be an additional thin film layer deposited on a wafer.

[0084] Of course, the opening direction of the back cavity groove is perpendicular to the direction of the device array layer 200 and faces outwards. For details, please refer to the relevant technology, and the present invention will not elaborate on this.

[0085] The present invention also provides a method for preparing an ultrasonic transducer, the corresponding flow diagram of which is shown in FIG3 , referred to as a third specific embodiment, including:

[0086] S101 : a piezoelectric material layer 211 is provided on an insulating layer 300 , wherein the insulating layer 300 includes a plurality of vibration structure units 310 .

[0087] In actual production, the insulating layer 300 is often received in the form of a large wafer. After receiving the large wafer, it is necessary to first plate the upper electrode layer 212 on its surface, and then cut it into wafer blocks of the size required for a single ultrasonic transducer. The cut wafer blocks are bonded to the IC substrate 100.

[0088] It should be noted that the order of step S101 is not fixed, and the order of the following steps can be adjusted according to actual conditions, and the present invention does not limit this.

[0089] S102 : coating an upper electrode layer 212 on a first surface of the piezoelectric material layer 211 , where the first surface is the surface of the piezoelectric material layer 211 away from the insulating layer 300 .

[0090] S103: cutting the first surface coated with the upper electrode layer 212 to obtain a plurality of array elements arranged in an array.

[0091] In combination with the above, the array element is the transducer unit 210 without the metal protrusion 213. After this step, the structure diagram of the plurality of array elements arranged in an array is shown in FIG4.

[0092] In this step, the upper electrode layer 212 can be cut by only cutting a portion of the piezoelectric material layer 211, that is, not completely cutting the piezoelectric material layer 211, or the piezoelectric material layer 211 can be completely cut. The method can be adjusted according to actual conditions, but the upper electrode layer 212 must be cut to form insulation between the array elements.

[0093] S104 : The array element is transformed into a transducer unit 210 by implanting a metal protrusion 213 on the array element, thereby obtaining the element array layer 200 .

[0094] In this step, after all array elements are implanted into the metal protrusions 213 , the array elements arranged in the entire layer constitute the device array layer 200 .

[0095] S105 : Soldering the device array layer 200 to the IC substrate 100 via the metal protrusions 213 .

[0096] After soldering the metal bump 213 to the IC substrate 100 in this step, the upper electrode of the transducer unit 210 is connected to the IC. Of course, the lower electrode of the transducer unit 210 (the upper electrode and the lower electrode are the positive and negative electrodes of the transducer unit 210, respectively) also needs to be connected to the IC substrate 100, but this will not be described in detail in this disclosure. After the transducer unit 210 and IC substrate 100 are electrically connected, a power-on check can be performed to ensure that the connection is correct and that the transducer unit 210 is functioning properly.

[0097] Furthermore, the metal protrusion 213 is connected to the IC substrate 100 by reflow soldering.

[0098] Reflow soldering can achieve precise soldering with a relatively low current, greatly reducing the possibility of component damage during the soldering process and the possibility of cold solder joints, thereby significantly improving the yield rate of the finished product. Of course, other soldering methods, such as hot press soldering or hot air soldering, can also be used according to actual needs, and the present invention is not limited to this method.

[0099] The preparation method of the ultrasonic transducer in this specific embodiment corresponds to the ultrasonic transducer in the previous text. The specific aggregation details can be referred to the previous text, and this specific embodiment will not be repeated here.

[0100] Preferably, the metal bumps 213 on the array element are implanted using at least one of the FCBGA (Flip Chip Ball Grid Array) and LFBGA (Low-Profile Fine-Pitch Ball Grid Array) processes. Accordingly, the metal bumps 213 are solder balls. Utilizing these two ball grid implantation processes significantly reduces the time required to install the metal bumps 213, improving production efficiency. Of course, the metal bumps 213 can also be indium pillars or other metal structures, and other implantation techniques can be used as needed, which is not limited by the present invention.

[0101] The ultrasonic transducer preparation method provided by the present invention comprises the following steps: coating a first surface of a piezoelectric material layer 211 with an upper electrode layer 212; cutting the first surface coated with the upper electrode layer 212 to obtain a plurality of array elements arranged in an array; implanting metal protrusions 213 on the array elements to convert the array elements into transducer units 210 to obtain an element array layer 200; soldering the element array layer 200 to an IC substrate 100 via the metal protrusions 213; and providing an insulating layer 300 on the second surface of the piezoelectric material layer 211, the insulating layer 300 including a plurality of vibration structure units 310. In the present invention, the transducer unit 210 is flipped, and the upper electrode layer 212 with the metal protrusions 213 is inversely soldered to the underlying IC substrate 100 in direct contact. This provides a strong structure, simple process, and low cost. It also ensures the shortest signal transmission path, minimizes interference, and reduces attenuation, thereby greatly improving signal transmission reliability and signal quality.

[0102] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the methods.

[0103] It should be noted that, in this specification, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0104] The ultrasonic transducer and its preparation method provided by the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An ultrasonic transducer, characterized in that: From bottom to top, it includes an IC substrate, a component array layer, and an insulating layer; The element array layer includes a plurality of transducer units; The transducer unit includes an upper electrode layer and a piezoelectric material layer; The transducer unit is welded to the IC substrate via the metal protrusions on the upper electrode layer; The insulating layer includes a plurality of vibration structure units.

2. The ultrasonic transducer according to claim 1, wherein The vibration structure unit is provided with a back cavity groove in a direction perpendicular to the element array layer; The diameter of the back cavity groove gradually decreases from the opening to the bottom of the groove.

3. The ultrasonic transducer according to claim 1, wherein Also included is a porous heat dissipation substrate; The surface of the IC substrate away from the metal protrusion is fixedly connected to the porous heat dissipation substrate.

4. The ultrasonic transducer according to claim 1, wherein The IC substrate is an ASIC substrate.

5. The ultrasonic transducer according to claim 1, wherein Also included are electronic insulating glues; The electronic insulating glue is filled between adjacent transducer units.

6. The ultrasonic transducer according to claim 1, wherein Also included is an acoustic impedance matching layer; The acoustic impedance matching layer at least covers the outer surface of the insulating layer.

7. The ultrasonic transducer according to claim 6, wherein: The acoustic impedance matching layer also includes a conductive adhesive layer; The insulating layer insulates the element array layer from the conductive adhesive layer.

8. The ultrasonic transducer according to any one of claims 1 to 7, characterized in that: The lower electrodes of the plurality of transducer units are connected to the IC substrate through at least one of coaxial cables, gold wire bonding, and through silicon vias.

9. A method for preparing an ultrasonic transducer, characterized in that: include: A piezoelectric material layer is provided on the insulating layer, wherein the insulating layer includes a plurality of vibration structural units; An upper electrode layer is plated on the first surface of the piezoelectric material layer. The first surface is the The electrical material layer is away from the surface of the insulating layer; Cutting the first surface coated with the upper electrode layer to obtain a plurality of array elements; By implanting metal protrusions on the array elements, the array elements are converted into transducer units to obtain an element array layer; The element array layer is welded to the IC substrate through the metal protrusions.

10. The method for preparing an ultrasonic transducer according to claim 9, wherein: The metal protrusion is connected to the IC substrate through reflow soldering.

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