WO2021248539A1

WO2021248539A1 - Piezoelectric structure and piezoelectric apparatus

Info

Publication number: WO2021248539A1
Application number: PCT/CN2020/096915
Authority: WO
Inventors: 段炼; 张睿
Original assignee: 瑞声声学科技(深圳)有限公司
Priority date: 2020-06-12
Filing date: 2020-06-19
Publication date: 2021-12-16
Also published as: CN111682097A; CN111682097B

Abstract

A piezoelectric structure and a piezoelectric apparatus. The piezoelectric structure comprises a substrate (1), a first conductive layer arranged above the substrate (1), and a second conductive layer spaced apart from the first conductive layer. The piezoelectric structure further comprises a fixed arm (7) located above the substrate (1), and a connecting part (5) that extends along the fixed arm (7), wherein the fixed arm (7) comprises a first fixed arm (73) fixedly connected to the side of the first conductive layer that faces away from the substrate (1), a second fixed arm (71) fixedly connected to the side of the second conductive layer that faces away from the substrate (1), and a cantilever (72) that connects the first fixed arm (73) and the second fixed arm (71); and the connecting part (5) successively extends along the first fixed arm (73), the cantilever (72) and the second fixed arm (71), and electrically connects the second conductive layer and the first conductive layer. According to the technical solution, by means of providing the cantilever (72), the dependence of same on providing a connection part on the surface of a piezoelectric thin film can be prevented.

Description

Piezoelectric structure and piezoelectric device

Technical field

The invention relates to the field of piezoelectric MEMS chips, in particular to piezoelectric structures.

Background technique

The application fields of piezoelectric MEMS devices are becoming more and more extensive, and the reliability requirements of the devices are also getting higher and higher. The diaphragm layer of the piezoelectric MEMS in the piezoelectric MEMS device is generally composed of a single layer or multiple layers of piezoelectric materials and electrode materials. 1 and 2, the existing piezoelectric MEMS device is mainly a typical cantilever beam thin film piezoelectric MEMS device, including an effective electrode 100, a structure electrode 200, a piezoelectric material 300, and a fixed end 400 of the piezoelectric film. .

Please refer to FIG. 3, a typical piezoelectric MEMS film includes multiple sets of effective electrode portions, as shown in the figure, the effective electrode portions A, B, and C. The effective electrode portions A, B, and C respectively include multilayer electrodes and are sandwiched between the electrodes. The piezoelectric material in between, and the piezoelectric material of the corresponding layer of each effective electrode part are integrally arranged. The different electrode layers of each effective electrode portion and the electrodes of each effective electrode portion are electrically connected through the electrode connector 40, and finally the piezoelectric signal is output through the gold wire 60. Specifically, each effective electrode portion is provided with Connecting the electrode connecting holes of different electrode layers, a part of the electrode connecting body 40 is arranged on the wall of the electrode connecting hole to electrically connect the electrodes of different layers of each effective electrode part, and the other part of the electrode connecting body is arranged on the surface of the film to electrically connect each electrode. The electrode of the adjacent effective electrode part. However, in some cases, in order to avoid risks such as short circuits, adjacent effective electrode portions are not suitable for electrical connection through the electrode connector 40 provided on the surface of the film. In addition, in the case of FIG. 4, the bonding pad of the gold wire is separated from the piezoelectric material of the effective electrode portion, and the electrode of the pad and the effective electrode portion cannot be connected through the electrode connector provided on the surface of the film. Similarly, when each effective electrode portion and its piezoelectric material are arranged separately, the effective electrode portions cannot be connected to each other through the electrode connecting body 40 provided on the surface of the piezoelectric material, so as to transmit the signal collected by the effective electrode to The pad is connected through the gold wire 60.

technical problem

The purpose of the present invention is to provide a piezoelectric structure, which aims to solve the problem in the prior art that the two electrodes or the electrode and the pad cannot or are not directly electrically connected through the electrode connector on the surface of the piezoelectric film.

Technical solutions

The first technical solution adopted by the present invention is to provide a piezoelectric structure, which includes a substrate, a first conductive layer disposed above the substrate, and a second conductive layer spaced apart from the first conductive layer, and also includes A fixed arm above the substrate and a connecting portion extending along the fixed arm, the fixed arm includes a first fixed arm fixedly connected to the first conductive layer on a side away from the substrate, and a second conductive layer A second fixed arm fixedly connected to the side of the layer away from the substrate and a cantilever connecting the first fixed arm and the second fixed arm, and the connecting portion sequentially runs along the first fixed arm, the cantilever, and the second fixed arm. The arm extends and electrically connects the second conductive layer and the first conductive layer.

Further, the connecting portion is at least partially disposed on the surface of the fixed arm.

Further, the connecting portion is buried in the fixed arm.

Further, the piezoelectric structure includes a first electrode portion disposed above the substrate, the first electrode portion includes a plurality of electrode layers spaced apart and stacked, and the piezoelectric structure further includes a first electrode portion disposed above the substrate. The first piezoelectric material part between the electrode layers of an electrode part, and the first conductive layer is the electrode layer of the first electrode part away from the substrate.

Further, the piezoelectric structure further includes a second electrode portion spaced apart from the first electrode portion, the second electrode portion includes a plurality of electrode layers spaced apart and stacked, and the piezoelectric structure further includes The second piezoelectric material portion between the electrode layers of the second electrode portion, and the second conductive layer is the electrode layer on the side of the second electrode portion away from the substrate.

Further, the first piezoelectric material part and the second piezoelectric material part are spaced apart.

Further, the first piezoelectric material part and the second piezoelectric material part are integrally arranged.

Further, the piezoelectric structure further includes a welding part spaced from the first electrode part, and the welding part includes the second conductive layer. The second technical solution adopted by the present invention is to provide a piezoelectric device including the above piezoelectric structure.

Beneficial effect

The beneficial effect of the present invention is that the two electrodes or the electrode and the pad can be connected at any position through the cantilever provided above the substrate and the connection part extending along the cantilever, so that the electrode signal extraction structure can be arranged more flexibly.

Description of the drawings

FIG. 1 is a top view of a typical piezoelectric film structure with a cantilever beam film in the prior art;

2 is a cross-sectional view of a typical piezoelectric film structure with a cantilever beam film in the prior art;

Fig. 3 is a schematic diagram of a typical electrode connection mode of a piezoelectric structure in the prior art;

Figure 4 is a schematic diagram of a typical piezoelectric structure in the prior art;

5 is a schematic diagram of the electrode connection mode of the piezoelectric structure in the first embodiment of the present invention;

6 is a schematic diagram of the electrode connection mode of the piezoelectric structure in the second embodiment of the present invention;

7 is a schematic diagram of the electrode connection mode of the piezoelectric structure in the third embodiment of the present invention;

Figure 8 is a schematic view of the electrode connection mode of the piezoelectric structure in the fourth embodiment of the present invention;

9 is a schematic diagram of the electrode connection mode of the piezoelectric structure in the fifth embodiment of the present invention;

FIG. 10 is a schematic diagram of the electrode connection mode of the piezoelectric structure in the sixth embodiment of the present invention.

Embodiments of the present invention

The present invention will be further described below in conjunction with the drawings and embodiments.

Please refer to FIG. 5, which is a schematic diagram of the piezoelectric film electrode connection method according to the first embodiment of the present invention. In the embodiment of the present invention, the piezoelectric structure includes a substrate 1, a thin film portion 11 and a welding portion 8 provided on the substrate 1, wherein the thin film portion 11 and the welding portion 8 are provided separately, and the thin film portion 11 includes a layered first An electrode portion 2. The piezoelectric structure further includes a fixed arm 7 located above the substrate 1 and a connecting portion 5 extending along the fixed arm 7. The fixed arm 7 includes a first fixed arm 73 fixedly connected to the welding portion 8, and The electrode part 2 is fixedly connected to the second fixed arm 71 on the side away from the substrate 1 and the cantilever 72 connecting the first fixed arm 73 and the second fixed arm 71. The arm 71 extends and electrically connects the welding part 8 and the first electrode part 2.

In this embodiment, an overhanging electrode connection method is adopted, and the fixed arm 7 is made of insulating material. Through the fixed arm 7 provided above the substrate 1 and the connecting portion 5 extending along the fixed arm 7, the separated electrodes or separated electrodes and pads provided on the surface of the substrate 1 can be connected, which not only solves the problem of electrode signal extraction, but also At the same time, it can ensure the stability of the connection part, and greatly reduce the signal interference of the external device to the connection part, and improve the effectiveness and reliability of signal transmission.

In this embodiment, the thin film portion 11 includes a first piezoelectric material portion 3 and a first electrode portion 2. The first electrode portion 2 includes a first electrode layer 21 provided on the surface of the substrate 1 and sequentially stacked on the first electrode. The second electrode layer 22 and the third electrode layer 23 above the layer 21, the first piezoelectric material portion 3 includes a first piezoelectric material layer 31 and a device disposed between the first electrode layer 21 and the second electrode layer 22 The second piezoelectric material layer 32 between the second electrode layer 22 and the third electrode layer 23. The soldering portion 8 includes a conductive layer 81 provided on the surface of the substrate 1, and the conductive layer 81 is a pad for soldering with the gold wire 6.

In this embodiment, the connecting portion 5 is at least partially disposed on the surface of the fixed arm 7. The connecting portion 5 includes a first central portion 52 and a first bending portion 51 and a second bending portion 53 respectively connected to both ends of the first central portion 52. The first bent portion 51 is embedded in the second fixed arm 71, the first central portion 52 is provided on the surface of the cantilever 72, and the second bent portion 53 is provided on the surface of the first fixed arm 73, thereby ensuring the stability of the connecting portion It solves the problem that the separate electrode and the pad used for welding with the gold wire cannot be directly connected through the surface of the piezoelectric film.

In this embodiment, the thin film portion 11 is further provided with electrode connection holes 13 connecting the electrode layers, and the electrode layers of the first electrode portion 2 are electrically connected through the electrode connection body 4 provided on the hole wall of the electrode connection hole 13. The electrode connection body 4 is connected to the pad 81 through the connecting portion 5, and finally the piezoelectric signal generated is output by the gold wire 6 connected to the pad 81.

In this embodiment, the thin film portion 11 further includes other electrode portions 2'arranged on each piezoelectric material layer of the first piezoelectric material portion 3 and spaced apart from the first electrode portion 2, the first electrode portion 2 and other electrode portions They are electrically connected by an electrode connector 4 provided on the surface of the film portion.

Please refer to FIG. 6, which is a schematic diagram of the piezoelectric film electrode connection method according to the second embodiment of the present invention. In this embodiment, the main difference between the piezoelectric structure and the first embodiment is that the connecting portion 5 is embedded in the fixed arm 7 in this embodiment, which can prevent the surface of the conductive electrode from being oxidized, corroded or peeled off. In this embodiment, the first bending portion 51 is buried in the second fixed arm 71, the first central portion 52 is buried in the cantilever 72, and the second bending portion 53 is buried in the first fixed arm 73. Compared with the first embodiment, this embodiment solves the problem that the separated electrode and the pad for welding with the gold wire cannot be directly connected through the surface of the piezoelectric film. At the same time, the fixed arm 7 in this embodiment is fixedly connected The effect of the part 5 is better, which can prevent the connection part 5 from breaking, improve the stability of the connection, and thereby ensure the effective transmission of electrical signals.

Please refer to FIG. 7, which is a schematic diagram of the piezoelectric film electrode connection mode of the third embodiment of the present invention. In this embodiment, the main difference between the piezoelectric structure and the first embodiment is that the electrical connection to the thin film portion 11 in this embodiment is not a pad structure soldered with gold wires, but is similar to the thin film portion 11 of the first embodiment. Another film part 12. The thin film portion 12 includes a second piezoelectric material portion 9 and a second electrode portion 10. The second electrode portion 10 includes a fourth electrode layer 101 provided on the surface of the substrate 1, and a fifth electrode layer 102 and a sixth electrode layer 103 sequentially stacked on the fourth electrode layer 101. The second piezoelectric material portion 9 It includes a third piezoelectric material layer 91 disposed between the fourth electrode layer 101 and the fifth electrode layer 102 and a fourth piezoelectric material layer 92 disposed between the fifth electrode layer 102 and the sixth electrode layer 103. The first piezoelectric material portion 8 and the second piezoelectric material portion 9 are spaced apart. The connection portion 5 extending along the cantilever 72 connects the thin film portion 11 with the other thin film portion 12, which solves the problem that the separated electrodes cannot be directly electrically connected through the electrode connector on the surface of the piezoelectric film.

Please refer to FIG. 8, which is a schematic diagram of a connection method of piezoelectric film electrodes according to a fourth embodiment of the present invention. In this embodiment, the difference between the piezoelectric structure and the second embodiment is mainly that the electrical connection with the thin film portion 11 in this embodiment is not a bonding pad structure welded with a gold wire, but is similar to the thin film portion 11 of the second embodiment. Another film part 12. The connection portion 5 extending along the cantilever 72 connects the thin film portion 11 to the other thin film portion 12, which solves the problem that the separated electrodes cannot be directly electrically connected through the electrode connector on the surface of the piezoelectric film.

Please refer to FIG. 9, which is a schematic diagram of a connection mode of piezoelectric film electrodes according to a fifth embodiment of the present invention. In this embodiment, the main difference between the piezoelectric structure and the third embodiment is that the first piezoelectric material part 8 and the second piezoelectric material part 9 are integrally provided in this embodiment. The connecting portion 5 extending along the cantilever 72 connects the thin film portion 11 with the other thin film portion 12, which solves the problem that the electrodes are not suitable for electrical connection directly through the electrode connector on the surface of the piezoelectric film.

Please refer to FIG. 10, which is a schematic diagram of a piezoelectric film electrode connection method according to a sixth embodiment of the present invention. In this embodiment, the difference between the piezoelectric structure and the fourth embodiment is mainly that the first piezoelectric material portion 8 and the second piezoelectric material portion 9 are integrally provided in this embodiment. The connecting portion 5 extending along the cantilever 72 connects the thin film portion 11 with the other thin film portion 12, which solves the problem that the electrodes are not suitable for electrical connection directly through the electrode connector on the surface of the piezoelectric film. The present invention also provides a piezoelectric device, which includes the above-mentioned piezoelectric structure. For the specific structure of the piezoelectric structure, please refer to the above-mentioned embodiment, which will not be repeated here. Piezoelectric devices include piezoelectric MEMS microphones, piezoelectric speakers, and ultrasonic piezoelectric modules.

The present invention proposes several electrode connection schemes aiming at the fact that the separated electrodes or the electrodes and the pads cannot be directly electrically connected through the surface of the structure, which not only solves the problem of electrode signal extraction, but also ensures the stability of the connection part connection, and greatly Reduce the signal interference of external devices to the connection part, and improve the effectiveness and reliability of signal transmission.

The above are only the embodiments of the present invention. It should be pointed out here that for those of ordinary skill in the art, improvements can be made without departing from the inventive concept of the present invention, but these all belong to the present invention. The scope of protection.

Claims

A piezoelectric structure includes a substrate, a first conductive layer disposed above the substrate, and a second conductive layer spaced from the first conductive layer, and is characterized in that it further includes a fixed arm located above the substrate and A connecting portion extending along the fixed arm, the fixed arm includes a first fixed arm fixedly connected to the side of the first conductive layer away from the substrate, and fixed to the side of the second conductive layer away from the substrate A second fixed arm connected and a cantilever connecting the first fixed arm and the second fixed arm, the connecting portion extends along the first fixed arm, the cantilever and the second fixed arm in sequence and is electrically connected to the first fixed arm Two conductive layers and the first conductive layer.
The piezoelectric structure according to claim 1, wherein the connecting portion is at least partially disposed on the surface of the fixed arm.
The piezoelectric structure according to claim 1, wherein the connecting portion is buried in the fixed arm.
The piezoelectric structure according to claim 1, wherein the piezoelectric structure includes a first electrode portion disposed above the substrate, and the first electrode portion includes a plurality of electrode layers that are spaced and stacked, and The piezoelectric structure further includes a first piezoelectric material portion disposed between the electrode layers of the first electrode portion, and the first conductive layer is a side of the first electrode portion away from the substrate. Electrode layer.
The piezoelectric structure according to claim 4, wherein the piezoelectric structure further comprises a second electrode part spaced apart from the first electrode part, and the second electrode part comprises a plurality of spaced and stacked layers. An electrode layer, the piezoelectric structure further includes a second piezoelectric material portion disposed between the electrode layers of the second electrode portion, and the second conductive layer is a portion of the second electrode portion away from the substrate The electrode layer on one side.
The piezoelectric structure according to claim 5, wherein the first piezoelectric material part and the second piezoelectric material part are spaced apart.
The piezoelectric structure according to claim 5, wherein the first piezoelectric material part and the second piezoelectric material part are integrally provided.
The piezoelectric structure according to claim 4, wherein the piezoelectric structure further comprises a welding part spaced from the first electrode part, and the welding part comprises the second conductive layer.
A piezoelectric device, comprising the piezoelectric structure according to any one of claims 1-8.