Ultrasonic transducer

Abstract

The embodiment of the utility model discloses an ultrasonic transducer which comprises a base body, a vibrating diaphragm, a first electrode and a second electrode. The base body is provided with a first combination face and a second combination face which are oppositely arranged, the vibrating diaphragm is arranged on the first combination face, the first electrode is arranged on the vibrating diaphragm, and the second electrode is arranged on the second combination face. The base body is provided with a conductive piece between the first bonding surface and the second bonding surface, the second bonding surface is provided with a bonding pad, and two ends of the conductive piece are electrically connected to the bonding pad and the first electrode respectively. By arranging the conductive piece and the bonding pad on the base body, the first electrode and the bonding pad can be electrically connected together, so that the first electrode is guided to the second bonding surface of the base body, the consistency of the wiring end surface can be ensured, rapid wiring is facilitated, subsequent maintenance is facilitated, wires are arranged neatly and neatly, and the wiring quality is improved. And the wire winding phenomenon is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of ultrasonic imaging, in particular to an ultrasonic transducer. Background Art

[0002] An ultrasonic transducer (also called an ultrasonic probe) is one of the key components of a medical ultrasonic imaging device. In related technologies, MEMS (Micro-Electro-Mechanical System) technology is used to prepare a piezoelectric ultrasonic transducer. Its composition structure from bottom to top includes: a base layer, a lower electrode, a piezoelectric layer, an upper electrode, and a passive layer. Among them, the upper electrode and the lower electrode serve as the positive and negative electrodes of the transducer and can be used to externally connect electrical components.

[0003] In the transducer of related technologies, the upper electrode and the lower electrode are arranged on different end faces of the base layer, and the end faces where the connection positions of the upper electrode and the corresponding electrical component are located and the end faces where the connection positions of the lower electrode and the corresponding electrical component are located are on different end faces. This makes the wiring end faces inconsistent when wiring the upper electrode and the lower electrode, resulting in inconvenient wiring, and the leads are prone to winding after wiring. Summary of the Utility Model

[0004] Based on this, it is necessary to propose an ultrasonic transducer that is convenient for electrode wiring in view of the above problems.

[0005] An embodiment of the utility model provides an ultrasonic transducer, including:

[0006] A substrate having a first bonding surface and a second bonding surface arranged opposite to each other;

[0007] A diaphragm arranged on the first bonding surface;

[0008] A first electrode arranged on the diaphragm;

[0009] A second electrode arranged on the second bonding surface;

[0010] A conductive member is arranged between the first bonding surface and the second bonding surface of the substrate. A pad is arranged on the second bonding surface. Two ends of the conductive member are electrically connected to the pad and the first electrode respectively.

[0011] In some embodiments, a through hole penetrates through the substrate, and two ends of the through hole extend to the first bonding surface and the second bonding surface respectively, and the conductive member is filled in the through hole.

[0012] In some embodiments, the through hole is rectangular, circular or annularly arranged, the through hole is formed in the substrate by etching, and the radial dimension of the through hole is 20μm - 80μm.

[0013] In some embodiments, the substrate is made of silicon or silicate glass. The inner wall of the through hole is covered with a resistance layer made of an insulating material, and the conductive member is filled in the resistance layer.

[0014] In some embodiments, a dielectric layer is provided on the first joint surface. A groove is formed at one end of the dielectric layer facing away from the substrate. The diaphragm is disposed on the end surface of the dielectric layer facing away from the substrate and covers the groove. The first electrode is disposed at one end of the diaphragm facing away from the dielectric layer, and the first electrode is disposed opposite to the groove.

[0015] In some embodiments, the first electrode, the diaphragm, and the dielectric layer can be combined to form a transducer unit. A plurality of the transducer units are provided on the substrate, and the plurality of transducer units are spaced apart.

[0016] In some embodiments, the first electrode is combined with the diaphragm by physical vapor deposition, thermal evaporation, or electron beam evaporation processes. The size of the first electrode is less than or equal to the size of the diaphragm, and the thickness of the first electrode is 100 nm - 1 μm.

[0017] In some embodiments, the second electrode is combined with the second joint surface by low-pressure chemical vapor deposition or physical vapor deposition processes. The thickness of the second electrode is 100 nm - 1 μm.

[0018] In some embodiments, a passivation layer with insulation is coated outside both the first electrode and the second electrode. The thickness of the passivation layer is greater than the thicknesses of the first electrode and the second electrode.

[0019] In some embodiments, a plurality of the first electrodes are provided on the diaphragm. A pad and a lead are also provided on the diaphragm. The pad on the diaphragm is electrically connected to the first electrode through the lead, and the pad on the diaphragm and the pad on the second joint surface are electrically connected through the conductive member.

[0020] Adopting the embodiments of the present invention has the following beneficial effects:

[0021] According to the ultrasonic transducer in the above embodiments, by providing a conductive member and a pad on the substrate, the first electrode and the pad can be electrically connected together through the conductive member, so as to guide the first electrode to the second joint surface of the substrate, that is, the cooperation of the conductive member and the pad can guide the wiring end surface of the first electrode to be coplanar with the second electrode. In this way, compared with the wiring end surfaces of the two opposite electrodes being located on different end surfaces, the wiring end surfaces of the first electrode and the second electrode of the present application and the component are located on the same end surface of the substrate, which can ensure the consistency of the wiring end surfaces, facilitate quick wiring and subsequent maintenance, and is conducive to the neat arrangement of the wires without chaos, avoiding the phenomenon of wire winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Among them:

[0024] Figure 1 shows a cross-sectional view of an ultrasonic transducer provided by the present invention;

[0025] Figure 2 shows another cross-sectional view of an ultrasonic transducer provided by the present invention;

[0026] Figure 3 shows still another cross-sectional view of an ultrasonic transducer provided by the present invention.

[0027] MAIN SYMBOL DESCRIPTION OF ELEMENTS:

[0028] 1. Substrate; 11. First joint surface; 12. Second joint surface; 13. Through hole; 14. Electrically insulating layer; 15. Conductive member; 16. Second electrode; 2. Diaphragm; 21. First electrode; 3. Pad; 31. Lead; 4. Passivation layer; 5. Dielectric layer; 51. Groove; 6. Transducing unit; 7. Isolation groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0030] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this utility model pertains. The terms used herein in the specification of this utility model are only for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0032] This utility model provides an ultrasonic transducer that can be applied to medical ultrasonic imaging equipment. In one embodiment, please refer to Figure 1 , the ultrasonic transducer includes a base body 1, a diaphragm 2, a first electrode 21, and a second electrode 16. Among them, the base body 1 is the carrier and support of the entire transducer. The base body 1 can provide an installation environment for the remaining components. In this regard, the base body 1 has a first bonding surface 11 and a second bonding surface 12 that are oppositely arranged.

[0033] The diaphragm 2 is arranged on the first bonding surface 11. The diaphragm 2 is the key component for realizing the electromechanical conversion function of the transducer. It can vibrate and deform under the action of an electrostatic field to convert mechanical energy and electrical energy into each other.

[0034] The first electrode 21 is arranged on the diaphragm 2, and the second electrode 16 is arranged on the second bonding surface 12. The first electrode 21 and the second electrode 16 form the positive and negative electrodes when the transducer is externally electrically connected. By externally connecting electrical components through the first electrode 21, an electrical signal can be applied to the diaphragm 2 or the diaphragm 2 can receive an electrical signal. By externally connecting electrical components through the first electrode 21, an external electrical signal can be applied to the substrate. This cooperation between the first electrode 21 and the second electrode 16 can provide an electrostatic field environment for the diaphragm 2.

[0035] A conductive member 15 is arranged between the first bonding surface 11 and the second bonding surface 12 of the base body 1. A solder pad 3 is arranged on the second bonding surface 12. The two ends of the conductive member 15 are respectively electrically connected to the solder pad 3 and the first electrode 21.

[0036] When using the transducer, in order to provide an electrostatic field environment for the diaphragm 2, the first electrode 21 and the second electrode 16 can serve as the positive and negative electrodes of the transducer, and the first electrode 21 and the second electrode 16 are electrically connected to corresponding electrical components through wires respectively. In this application, by providing a conductive member 15 and a pad 3 on the substrate 1, the first electrode 21 and the pad 3 can be electrically connected together through the conductive member 15, so as to guide the first electrode 21 to the second bonding surface 12 of the substrate 1, that is, the cooperation of the conductive member 15 and the pad 3 can guide the wiring end face of the first electrode 21 to be coplanar with the second electrode. In this way, compared with the wiring end faces of the two opposite electrodes being located on different end faces, the wiring end faces of the first electrode 21 and the second electrode 16 of this application are located on the same end face of the substrate 1, which can ensure the consistency of the wiring end faces, facilitate quick wiring and subsequent maintenance, and is conducive to the neat arrangement of the wires without confusion, avoiding the phenomenon of winding and tangling of the wires.

[0037] In an embodiment, please refer to Figure 1 , the substrate 1 is penetrated with a through hole 13, and both ends of the through hole 13 extend to the first bonding surface 11 and the second bonding surface 12 respectively, and the conductive member 15 is filled in the through hole 13. The conductive member 15 can be highly doped polysilicon, copper metal, tungsten metal or other metal conductive substances.

[0038] In a specific embodiment, the through hole 13 can be set in a rectangular, circular or annular shape, and the through hole 13 is formed in the substrate 1 by etching. In order to achieve good electrical conductivity and contact, the radial dimension of the through hole 13 is 20μm - 80μm. According to the actual situation, the radial dimension of the through hole 13 can be 20μm, 50μm or 80μm. As a structure penetrating the substrate 1, the depth of the through hole 13 is the same as the thickness of the substrate 1. However, in some cases, the initial thickness of the substrate 1 is relatively thick, exceeding the optimal etching thickness range of the etching technology. At this time, the size of the through hole 13 (generally between dozens of microns and hundreds of microns) can be determined first, and then etched at one end of the substrate 1, and then the material at the other end of the substrate 1 can be ground off by grinding, that is, the thickness of the substrate 1 is reduced at the other end of the substrate 1 so that the through hole 13 penetrates the substrate 1.

[0039] It should be noted that the substrate 1 of the present utility model is preferably made of silicon or silicate glass, so that the substrate 1 itself has conductive properties. In order to prevent the first electrode 21 from being electrically connected to the substrate 1, a resistive layer 14 made of an insulating material needs to be covered on the inner wall of the through hole 13, and the conductive member 15 is filled in the resistive layer 14. The material of the barrier layer can be one or more of silicon oxide, silicon nitride and silicon oxynitride, which is not limited here.

[0040] To ensure the filling stability and uniformity of the resistive layer 14 and the conductive member 15, low-pressure chemical vapor deposition or physical vapor deposition processes are generally used for filling and deposition.

[0041] When the substrate 1 is silicon or silicate glass, an annular through-hole 13 can be directly etched at the corresponding position of the substrate 1, and the columnar structure surrounded in the middle of the through-hole 13 and separated from the substrate 1 can be directly used as the conductive member 15. Then, by filling and depositing a barrier layer in the annular through-hole 13, the conductive member 15 can be isolated from the substrate 1.

[0042] Both ends of the resistive layer 14 also extend to the first bonding surface 11 and the second bonding surface 12. A part of the structure of the first electrode 21 is attached to the resistive layer 14, and the other structure is attached to the conductive member 15, so that the first electrode 21 and the conductive member 15 are electrically connected. Similarly, a part of the structure of the pad 3 on the second bonding surface 12 is fixed to the resistive layer 14, and the rest is connected to the conductive member 15, so that the pad 3 on the second bonding surface 12 is electrically connected to the conductive member 15. In this way, the first electrode 21 can be interconnected with the pad 3 on the second bonding surface 12 through the conductive member 15.

[0043] It should be noted that, please also combine Figure 2 , multiple first electrodes 21 are provided on the diaphragm 2. The diaphragm 2 can also be provided with pads 3 and leads 31. The multiple first electrodes 21 are connected to the pads 3 on the diaphragm 2 through the leads 31. One pad 3 or multiple pads 3 can be provided on the diaphragm 2. All the first electrodes 21 can be connected to one pad 3, or some of the first electrodes 21 can be connected to one pad 3, and the other part of the first electrodes 21 can be connected to other pads 3. At this time, only by electrically connecting the pads 3 on the diaphragm 2 and the pads 3 on the second bonding surface 12 through the conductive member 15 can the first electrodes 21 be guided to the second bonding surface 12. The pads 3 on the diaphragm 2 and the second bonding surface 12 can both be set as circular, rectangular or other polygons. When the pad 3 is a polygon structure, its side length dimension is 40 - 100 μm, and the side length dimension of the specific pad 3 can preferably be 40 μm or 70 μm or 100 μm.

[0044] In one embodiment, a dielectric layer 5 is provided on the first bonding surface 11. The dielectric layer 5 is mainly composed of non-conductive materials such as silicon oxide or silicon nitride with a relatively high dielectric constant, which can mainly isolate the diaphragm 2 and the substrate 1 and prevent electrode breakdown under a strong electric field. The thickness of the dielectric layer 5 made of the same material affects the breakdown voltage and the collapse voltage. Generally, the thicker the dielectric layer 5, the greater the breakdown voltage and the greater the collapse voltage. In order to obtain a good breakdown voltage, the thickness of the dielectric layer 5 is generally in the range of dozens to hundreds of nanometers. The dielectric layer 5 can usually be set on the first bonding surface 11 by semiconductor thin film deposition processes such as furnace tube thermal oxidation, low-pressure chemical vapor deposition, plasma-enhanced chemical vapor deposition, or high-density chemical vapor deposition to obtain good uniformity and consistency.

[0045] A groove 51 is formed at one end of the dielectric layer 5 facing away from the substrate 1. The diaphragm 2 can be bonded or deposited by a thin film or other processes on the end surface of the dielectric layer 5 facing away from the substrate 1, and the diaphragm 2 covers the groove 51. The groove 51 is a moving space for the up and down vibration of the diaphragm 2, which directly determines the vacuum gap of the transducer. It should be noted that the bonding process can be direct bonding, anodic bonding, adhesive bonding, etc. Bonding is generally carried out in a high-vacuum environment, which can ensure that the cavity formed between the diaphragm 2 and the groove 51 is vacuum, so that the diaphragm 2 has the least resistance when vibrating.

[0046] The material, size, and thickness of the diaphragm 2 directly determine the resonant frequency of the transducer and are the most important structures affecting the performance of the transducer. The material of the diaphragm 2 can be silicon or silicon nitride commonly used in semiconductor processes. The shape of the diaphragm 2 can be circular, square, rectangular, or polygonal such as hexagonal, octagonal, etc. The size of the diaphragm 2 depends on the requirements of different application scenarios and is usually in the range of dozens of microns to hundreds of microns. The thickness of the diaphragm 2 can vary in the range of hundreds of nanometers to several microns or even dozens of microns according to the application design requirements.

[0047] The shape of the groove 51 can be circular, square, rectangular, oval, bowl-shaped, trapezoidal, or other polygons. The size of the groove 51 is usually in the range of dozens of microns to hundreds of microns. The depth of the groove 51 mainly affects the parasitic capacitance and the collapse voltage of the transducer. According to the application design requirements, the depth of the groove 51 generally varies from hundreds of nanometers to dozens of microns.

[0048] The uniformity and consistency of the depth of the groove 51 are also important for the performance of the transducer. It is usually formed on the dielectric layer 5 by mature dry etching or wet etching processes to achieve better uniformity and consistency. In particular, a silicon-on-insulator wafer with a groove 51 structure can also be directly used as the dielectric layer 5 to simplify the process.

[0049] The first electrode 21 is provided at one end of the diaphragm 2 facing away from the dielectric layer 5, and the first electrode 21 is disposed opposite to the groove 51.

[0050] Specifically, the first electrode 21 is combined with the diaphragm 2 by physical vapor deposition, thermal evaporation or electron beam evaporation process. The first electrode 21 can be made of gold, platinum, aluminum, copper or other metals with good conductivity. The size of the first electrode 21 is less than or equal to the size of the diaphragm 2, and the thickness of the first electrode 21 is 100 nm - 1 μm.

[0051] It is worth mentioning that the first electrode 21, the diaphragm 2 and the dielectric layer 5 can form a transducer unit 6 together. A plurality of transducer units 6 are arranged on the substrate 1, and the plurality of transducer units 6 are arranged at intervals. Specifically, when setting, the dielectric layer 5 arranged on the substrate 1 is an integral structure, that is, one dielectric layer 5 is shared by a plurality of transducer units 6, and the diaphragm 2 arranged on the dielectric layer 5 is also an integral structure, and the diaphragm 2 is shared by a plurality of transducer units 6. Then, isolation grooves 7 are opened at the corresponding positions of the diaphragm 2 and the dielectric layer 5 between two adjacent transducer units 6. The isolation grooves 7 can divide a certain gap between two adjacent transducer units 6, thereby isolating the crosstalk of acoustic signals and improving the signal-to-noise ratio.

[0052] In addition, the second electrode 16 is formed on the second bonding surface 12 by low-pressure chemical vapor deposition or physical vapor deposition process, and the thickness of the second electrode 16 is 100 nm - 1 μm. When the substrate 1 is silicon or silicate glass, it can be directly formed on the second bonding surface 12 of the substrate 1 without considering the setting of a support structure, or the entire highly doped low-resistance silicon substrate 1 can also be used as the lower electrode. At this time, its resistivity should preferably be less than 1.5 milliohm-cm.

[0053] In a specific embodiment, please refer to Figure 1 and Figure 3 , a passivation layer 4 with insulation setting is coated outside both the first electrode 21 and the second electrode 16. The thickness of the passivation layer 4 is generally 300 nm - 2 μm, and the thickness of the passivation layer 4 is greater than the thicknesses of the first electrode 21 and the second electrode 16, so as to ensure that the passivation layer 4 can wrap the first electrode 21 and the second electrode 16 entirely. Of course, when there are multiple first electrodes 21 and the multiple first electrodes 21 are connected to the pad 3 through the lead 31, the passivation layer 4 needs to open a hole for the lead 31 to lead out. By setting the passivation layer 4, and the passivation layer 4 is usually one or a combination of silicon oxide, silicon nitride or silicon oxynitride, it plays a role in protecting the electrode, isolating water vapor, pollution and preventing electrical short circuit.

[0054] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brief description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not conflict, it should be considered as the scope described in this specification.

[0055] The above-described embodiments merely represent several implementation manners of the present utility model. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patented application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several modifications and improvements can still be made, and these all fall within the protection scope of the present utility model. Therefore, the protection scope of the patent of the present utility model shall be subject to the appended claims.

Claims

1. An ultrasonic transducer, characterized in that, Comprising: A substrate having a first bonding surface and a second bonding surface disposed opposite to each other; A diaphragm disposed on the first bonding surface; A first electrode disposed on the diaphragm; A second electrode disposed on the second bonding surface; A conductive member is disposed between the first bonding surface and the second bonding surface of the substrate, a pad is disposed on the second bonding surface, and two ends of the conductive member are electrically connected to the pad and the first electrode respectively.

2. The ultrasonic transducer according to claim 1, characterized in that, The substrate has a through hole penetrating therethrough, and two ends of the through hole extend to the first bonding surface and the second bonding surface respectively, and the conductive member is filled in the through hole.

3. The ultrasonic transducer according to claim 2, wherein The through hole is rectangular, circular or annularly arranged, the through hole is formed in the substrate by etching, and a radial dimension of the through hole is 20 μm - 80 μm.

4. The ultrasonic transducer according to claim 3, characterized in that, The substrate is made of silicon or silicate glass, an inner wall of the through hole is covered with a resistive layer made of an insulating material, and the conductive member is filled in the resistive layer.

5. The ultrasonic transducer according to claim 1, characterized in that, A dielectric layer is disposed on the first bonding surface, a groove is formed at an end of the dielectric layer facing away from the substrate, the diaphragm is disposed on an end face of the dielectric layer facing away from the substrate and covers the groove, the first electrode is disposed on an end of the diaphragm facing away from the dielectric layer, and the first electrode is disposed opposite to the groove.

6. The ultrasonic transducer according to claim 5, wherein The first electrode, the diaphragm and the dielectric layer can form a transducer unit in combination, a plurality of the transducer units are disposed on the substrate, and the plurality of transducer units are spaced apart.

7. The ultrasonic transducer according to any one of claims 1-6, characterized in that, The first electrode is combined with the diaphragm by physical vapor deposition, thermal evaporation or electron beam evaporation process, a size of the first electrode is less than or equal to a size of the diaphragm, and a thickness of the first electrode is 100 nm - 1 μm.

8. The ultrasonic transducer according to claim 7, characterized in that, The second electrode is combined with the second bonding surface by low-pressure chemical vapor deposition or physical vapor deposition process, and a thickness of the second electrode is 100 nm - 1 μm.

9. The ultrasonic transducer according to claim 8, characterized in that, Both the first electrode and the second electrode are coated with a passivation layer with insulation, and a thickness of the passivation layer is greater than thicknesses of the first electrode and the second electrode.

10. The ultrasonic transducer according to claim 1, characterized in that, A plurality of the first electrodes are disposed on the diaphragm, pads and leads are further disposed on the diaphragm, pads on the diaphragm are electrically connected to the first electrode through the leads, and pads on the diaphragm and pads on the second bonding surface are electrically connected through the conductive member.

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