CN115106274A

CN115106274A - MEMS transducer and manufacturing method thereof

Info

Publication number: CN115106274A
Application number: CN202210673722.8A
Authority: CN
Inventors: 王鹏辉; 杨云春
Original assignee: Beijing Haichuang Microchip Technology Co ltd
Current assignee: Beijing Haichuang Microchip Technology Co ltd
Priority date: 2022-06-14
Filing date: 2022-06-14
Publication date: 2022-09-27

Abstract

The invention relates to the technical field of transducers, in particular to an MEMS transducer, which comprises: the array antenna comprises a substrate and a thin film structure positioned on the substrate, wherein the thin film structure comprises a plurality of transducer elements, any two transducer elements in the transducer elements are electrically connected, the substrate comprises a plurality of cavities, and the positions of the cavities correspond to the positions of the transducer elements one by one. This MEMS transducer has realized setting up a plurality of different transducer array elements on MEMS transducer, and through the electric connection mode of different transducer array elements, reaches the demand according to different beam angles, sound pressure level or sensitivity, richenes and promotes the performance of MEMS transducer, improves the work efficiency of MEMS transducer, saves manufacturing cost, has integrated level height, the precision height and small advantage, still makes MEMS transducer possess the application ability of controlling the scanning mutually.

Description

MEMS transducer and manufacturing method thereof

Technical Field

The invention relates to the technical field of transducers, in particular to an MEMS transducer and a manufacturing method thereof.

Background

Today, a single transducer is typically made using MEMS technology and piezoelectric materials. At a certain frequency, the sound pressure level or sensitivity of a single transducer is fixed, the directivity is also determined, and the beam angle size and the beam direction cannot be changed. If a different sound pressure level, sensitivity, beam angle or beam direction is required for a certain transducer, the structure of the transducer needs to be redesigned, or a different single transducer is used, or multiple transducers are externally connected. Therefore, the conventional transducer has a problem of low operation efficiency.

Disclosure of Invention

The embodiment of the application provides a MEMS transducer and a manufacturing method, the technical problem that the transducer is low in working efficiency in the prior art is solved, the arrangement of a plurality of different transducer array elements on the MEMS transducer is realized, the requirements of different beam angles, sound pressure levels or sensitivity are met through the electric connection modes of different transducer array elements, the performance of the MEMS transducer is enriched and improved, the working efficiency of the MEMS transducer is improved, the production cost is saved, the MEMS transducer has the advantages of high integration level, high precision and small size, and the MEMS transducer is enabled to be provided with the technical effects of phase-controlled scanning application capacity and the like.

In a first aspect, embodiments of the present invention provide a MEMS transducer, including: the array antenna comprises a substrate and a thin film structure positioned on the substrate, wherein the thin film structure comprises a plurality of transducer elements, any two transducer elements in the transducer elements are electrically connected, the substrate comprises a plurality of cavities, and the positions of the cavities correspond to the positions of the transducer elements one by one.

Preferably, the thin film structure comprises: a lower electrode layer, a piezoelectric layer, and an upper electrode layer;

the lower electrode layer is located on the substrate, the piezoelectric layer is located on the lower electrode layer, and the upper electrode layer is located on the piezoelectric layer, wherein the lower electrode layer includes a plurality of first sub-electrodes, the upper electrode layer includes a plurality of second sub-electrodes, positions of the plurality of first sub-electrodes correspond to positions of the plurality of second sub-electrodes one-to-one, and one transducer array element is formed by one first sub-electrode, one second sub-electrode corresponding to the position of the first sub-electrode, and the piezoelectric layer.

Preferably, the thin film structure further comprises a passivation layer, and a metal pin of each of the plurality of transducer elements; the passivation layer is located over the upper electrode layer, and the metal pins of each transducer element are disposed in the passivation layer.

Preferably, the two arbitrary transducer elements are electrically connected in a series or parallel manner.

Preferably, the film structure further comprises a plurality of groups of release holes, and the positions of the plurality of groups of release holes correspond to the positions of the plurality of cavities one to one.

Based on the same inventive concept, in a second aspect, the present invention further provides a method for manufacturing a MEMS transducer, including:

forming a plurality of cavities in a substrate;

forming a thin film structure on the substrate after the plurality of cavities are formed, and forming a plurality of transducer elements in the thin film structure in the process of forming the thin film structure, wherein any two transducer elements in the plurality of transducer elements are electrically connected, and the positions of the plurality of cavities are in one-to-one correspondence with the positions of the plurality of transducer elements.

the forming a thin film structure over the substrate after forming the plurality of cavities includes:

forming the lower electrode layer over the substrate after the plurality of cavities are formed;

forming the piezoelectric layer over the lower electrode layer;

forming the upper electrode layer over the piezoelectric layer.

Preferably, the thin film structure further comprises a passivation layer;

after forming an upper electrode layer over the piezoelectric layer, further comprising:

the passivation layer is formed over the upper electrode layer.

Preferably, in the process of forming the thin film structure, forming a plurality of transducer elements in the thin film structure includes:

forming a plurality of first sub-electrodes in the lower electrode layer after forming the lower electrode layer over the substrate after forming the plurality of cavities and before forming the piezoelectric layer over the lower electrode layer;

forming a plurality of second sub-electrodes in the upper electrode layer after forming the upper electrode layer on the piezoelectric layer, wherein the positions of the plurality of first sub-electrodes correspond to the positions of the plurality of second sub-electrodes one-to-one;

and obtaining the multiple transducer elements through the multiple first sub-electrodes, the multiple second sub-electrodes and the piezoelectric layer, wherein one transducer element is formed by one first sub-electrode, one second sub-electrode corresponding to the position of the first sub-electrode and the piezoelectric layer.

Preferably, after forming the piezoelectric layer on the lower electrode layer and before forming the upper electrode layer on the piezoelectric layer, the method further includes:

forming a lower electrode pin hole of each of the plurality of first sub-electrodes in the piezoelectric layer;

after forming the passivation layer over the upper electrode layer, further comprising:

forming a lower electrode pin hole of each of the first sub-electrodes and an upper electrode pin hole of each of the second sub-electrodes in the plurality of second sub-electrodes in the passivation layer;

obtaining a metal pin of the transducer array element according to a lower electrode pin hole of the first sub-electrode and an upper electrode pin hole of the second sub-electrode corresponding to the position of the first sub-electrode, and obtaining the metal pin of each transducer array element;

and connecting any two transducer elements in series or in parallel through the metal pins of the two transducer elements.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

an embodiment of the present invention provides a MEMS transducer, which includes: the array antenna comprises a substrate and a thin film structure positioned on the substrate, wherein the thin film structure comprises a plurality of transducer elements, any two transducer elements in the transducer elements are electrically connected, the substrate comprises a plurality of cavities, and the positions of the cavities correspond to the positions of the transducer elements one by one. Through the MEMS transducer provided by the embodiment of the invention, a plurality of transducer array elements are designed on one MEMS chip, and are arranged and arrayed as required, and the transducer array elements form circuits in different connection modes as required, so that the requirements of different beam angles, sound pressure levels and sensitivities are met, the performance and the working efficiency of the MEMS transducer are improved, and the production cost is saved. The MEMS transducer has the advantages of high integration level, high precision and small volume, and also has the application capability of phase control scanning.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

FIG. 1 shows a schematic structural diagram of a MEMS transducer in an embodiment of the invention;

FIG. 2 illustrates a top view of etching a cavity in a substrate in an embodiment of the invention;

FIG. 3 illustrates a cross-sectional view of etching a cavity in a substrate in an embodiment of the invention;

FIG. 4 shows a top view of a lower electrode layer and a plurality of first sub-electrodes formed on a substrate in an embodiment of the invention;

FIG. 5 shows a cross-sectional view of a lower electrode layer and a plurality of first sub-electrodes formed on a substrate in an embodiment of the present invention;

FIG. 6 illustrates a top view of a piezoelectric layer formed over a lower electrode layer in an embodiment of the present invention;

FIG. 7 illustrates a cross-sectional view of forming a piezoelectric layer over a lower electrode layer in an embodiment of the present invention;

fig. 8 illustrates a top view of forming an upper electrode layer and a plurality of second sub-electrodes over a piezoelectric layer in an embodiment of the present invention;

fig. 9 illustrates a cross-sectional view of forming an upper electrode layer and a plurality of second sub-electrodes over a piezoelectric layer in an embodiment of the present invention;

FIG. 10 illustrates a top view of a passivation layer formed over the upper electrode layer in an embodiment of the present invention;

FIG. 11 illustrates a cross-sectional view of forming a passivation layer over the upper electrode layer in an embodiment of the present invention;

FIG. 12 shows a wiring schematic of a fabricated MEMS transducer in an embodiment of the invention;

FIG. 13 is a flow chart illustrating steps in a method of fabricating a MEMS transducer in an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

Example one

A first embodiment of the present invention provides a MEMS (Micro-Electro-Mechanical System) transducer, as shown in fig. 1, including: the transducer array structure comprises a substrate 1100 and a thin film structure 1200 located on the substrate 1100, wherein the thin film structure 1200 comprises a plurality of transducer elements 1260, any two transducer elements 1260 in the plurality of transducer elements 1260 are electrically connected, the substrate 1100 comprises a plurality of cavities 1101, and the positions of the plurality of cavities 1101 correspond to the positions of the plurality of transducer elements 1260 in a one-to-one mode.

Specifically, the substrate 1100 is an SOI (Silicon-On-Insulator) substrate. A plurality of cavities 1101 is provided in the substrate 1100. As shown in fig. 1, the empty areas recessed in the substrate 1100 represent cavities 1101, 3 cavities 1101 being shown in fig. 1. The positions of the plurality of cavities 1101 correspond to the positions of the plurality of transducer elements 1260 in a one-to-one manner, which means that the position of one transducer element 1260 corresponds to the position of one cavity 1101 in the substrate 1100, and the position of each transducer element 1260 corresponds to the position of one cavity 1101, namely, each transducer element 1260 corresponds to one cavity 1101. Function of cavity 1101: firstly, the corresponding transducer array 1260 realizes the transverse vibration, and secondly, the resonant frequency of the corresponding transducer array 1260 in the height direction is reduced.

The thin film structure 1200 includes: a lower electrode layer 1210, a piezoelectric layer 1220, and an upper electrode layer 1230. The lower electrode layer 1210 is located on the substrate 1100, the piezoelectric layer 1220 is located on the lower electrode layer 1210, and the upper electrode layer 1230 is located on the piezoelectric layer 1220. As shown in fig. 1, the location of the slanted stripe area on the substrate 1100 represents the lower electrode layer 1210, the location of the rhombus stripe area on the lower electrode layer 1210 represents the piezoelectric layer 1220, and the location of the black and white stripe area on the piezoelectric layer 1220 represents the upper electrode layer 1230.

The lower electrode layer 1210 includes a plurality of first sub-electrodes 1211, the upper electrode layer 1230 includes a plurality of second sub-electrodes 1231, the positions of the plurality of first sub-electrodes 1211 are in one-to-one correspondence with the positions of the plurality of second sub-electrodes 1231, and one transducer element 1260 is formed by one first sub-electrode 1211, the second sub-electrode 1231 corresponding to the position of the first sub-electrode 1211, and the piezoelectric layer 1220. Since the first sub-electrodes 1211 are formed by etching the lower electrode layer 1210, 3 first sub-electrodes 1211 are etched in the lower electrode layer 1210, as shown in fig. 1, the first sub-electrodes 1211 are represented by the slanted stripe regions above the substrate 1100. Similarly, since the second sub-electrodes 1231 are formed by etching the upper electrode layer 1230, 3 second sub-electrodes 1231 are etched in the upper electrode layer 1230, as shown in fig. 1, and the black and white grid-striped areas on the piezoelectric layer 1220 represent the second sub-electrodes 1231.

It should be noted that the positions of the plurality of first sub-electrodes 1211 correspond to the positions of the plurality of second sub-electrodes 1231 one by one, which means that the position of one first sub-electrode 1211 corresponds to the position of one second sub-electrode 1231, that is, one first sub-electrode 1211 corresponds to one second sub-electrode 1231. Each of the first sub-electrodes 1211 in the plurality of first sub-electrodes 1211 is located at a position corresponding to one of the second sub-electrodes 1231, that is, each of the first sub-electrodes 1211 is located at a position corresponding to one of the second sub-electrodes 1231. For each transducer element 1260 of the plurality of transducer elements 1260, a first sub-electrode 1211 and a second sub-electrode 1231 corresponding to the position of the first sub-electrode 1211, and the piezoelectric layer 1220 form a transducer element 1260, the position of a transducer element 1260 corresponding to the position of the cavity 1101 in a substrate 1100, i.e., the position of the first sub-electrode 1211 and the position of the second sub-electrode 1231 corresponding to the position of the first sub-electrode 1211 both correspond to the position of the cavity 1101.

Each transducer element 1260 of the plurality of transducer elements 1260 may be the same shape, different, or partially the same. The shape of each transducer element 1260 is set according to actual requirements. The shape of the individual transducer elements 1260 includes, but is not limited to, circular, square, or triangular. The array formed by the plurality of transducer elements 1260 includes, but is not limited to, a linear array, a planar array (e.g., an array formed by a plurality of transducer elements 1260 arranged in a square shape, or an array formed by a plurality of transducer elements 1260 arranged in a circular shape, etc.), or a circular array, and the array formed by the plurality of transducer elements 1260 may be set according to actual requirements for beam angle, sound pressure level, and sensitivity of the MEMS transducer.

In the arrangement formed by the plurality of transducer elements 1260, the distance between two adjacent transducer elements 1260 is set according to actual requirements. Typically, the distance between two adjacent transducer elements 1260 is no greater than one resonant wavelength of a single transducer element 1260.

Thin film structure 1200 also includes passivation layer 1240, and metal leads 1250 for each transducer element 1260 of the plurality of transducer elements 1260; passivation layer 1240 is positioned over upper electrode layer 1230 and metal leads 1250 for each transducer element 1260 are disposed in passivation layer 1240. As shown in fig. 1, the dotted stripe area above the upper electrode layer 1230 represents the passivation layer 1240.

It should be noted that, since each transducer element 1260 includes a first sub-electrode 1211 and a second sub-electrode 1231, there are two metal pins 1250 for each transducer element 1260, wherein one metal pin 1250 is the metal pin 1250 led out from the first sub-electrode 1211, and the other metal pin 1250 is the metal pin 1250 led out from the second sub-electrode 1231. Thus, the two metal pins 1250 of each transducer element 1260 represent the positive and negative poles of the transducer element 1260, respectively.

Any two transducer elements 1260 are connected in series or in parallel through the metal pins 1250 of any two transducer elements 1260, that is, the manner of electrically connecting any two transducer elements 1260 includes a series connection manner or a parallel connection manner. Different functions of the MEMS transducer are achieved by connecting the multiple transducer elements 1260 through different electrical connections via metal pins 1250 of each transducer element 1260 of the multiple transducer elements 1260.

It should be noted that any two transducer elements 1260 may be electrically connected in a manner that any two transducer elements 1260 are connected in series or in parallel in the MEMS transducer, or that there is no direct connection relationship between each transducer element 1260 in the MEMS transducer, and any two transducer elements 1260 are connected in series or in parallel or in other manners in the circuit with the MEMS transducer (i.e., the circuit formed by the MEMS transducer and the external circuit).

For example, an array formed by a plurality of transducer elements 1260 in a MEMS transducer as a receiver can realize the amplification of a detection charge signal, improve the sensitivity and regulate the beam angle. If the upper and lower electrodes of each transducer element 1260, or a partial array of the array formed by a plurality of transducer elements 1260, are connected to an external information processing unit, phased scanning of the received signals can be achieved by pre-forming the beams.

It should be noted that, in the plurality of transducer elements 1260 in the MEMS transducer as the receiver, there is no connection relationship between each transducer element 1260, and the upper and lower electrodes of each transducer element 1260 are connected to an external information processing unit, so that the phased scanning of the received signal can be realized by pre-forming the beam.

Or in a plurality of transducer elements 1260 in the MEMS transducer as a receiver, selecting some transducer elements 1260 to form a local array by serial connection or parallel connection, connecting the upper and lower electrodes of the transducer elements 1260 outside the local array and the local array with an external information processing unit, and realizing phase control scanning of received signals by pre-forming beams.

An array of multiple transducer elements 1260 in a MEMS transducer as a transmitter can achieve elevation of the source level and modulation of the beam angle. If the upper and lower electrodes of each transducer element 1260, or a partial array of a plurality of transducer elements 1260, are connected to an external information processing unit, the phase control scanning of the transmitted signals can be realized.

The membrane structure 1200 further includes a plurality of sets of release holes 1270, and the positions of the plurality of sets of release holes 1270 correspond to the positions of the plurality of cavities 1101 one to one.

Specifically, each set of release holes 1270 in the plurality of sets of release holes 1270 includes a plurality of release holes 1270, and the proper arrangement of the number of release holes 1270 and the different positions corresponding to the cavity 1101 will facilitate the release of the phosphosilicate glass PSG material in the cavity 1101 during the fabrication of the MEMS transducer. The position of each set of release holes 1270 corresponds to the position of one cavity 1101, i.e., each set of release holes 1270 corresponds to one cavity 1101. As shown in fig. 1, the cross-line areas in the membrane structure 1200 of fig. 1 are the release holes 1270, each cavity 1101 is located corresponding to one group of the release holes 1270, and each group of the release holes 1270 in fig. 1 includes two release holes 1270. Each release hole 1270 penetrates through the thin film structure 1200, i.e., each release hole 1270 penetrates through the lower electrode layer 1210, the piezoelectric layer 1220, the upper electrode layer 1230, and the passivation layer 1240 in sequence. The release hole 1270 functions to release a substance filled in the cavity 1101 during the fabrication of the MEMS transducer.

The working principle of the MEMS transducer of the embodiment is that a plurality of transducer array elements 1260 in the MEMS transducer are arranged and arrayed and connected in series and parallel to form different circuits, the working efficiency of the MEMS transducer is improved, various indexes of the MEMS transducer are improved, the performance of the MEMS transducer is improved, the transmitting sound pressure level, the receiving sensitivity and the size of received charges are improved, and the MEMS transducer can be externally connected with an electronic processing unit with phased transmitting/receiving to carry out wave beam angle scanning, so that the orientation and positioning effects of a detection target are realized.

In this embodiment, a plurality of transducer elements 1260 are designed on a MEMS chip, and the transducer elements 1260 are arranged and arrayed as needed, and the transducer elements 1260 form circuits of different connection modes as needed, so as to meet the requirements of different beam angles, sound pressure levels, and sensitivities, improve the performance and work efficiency of the MEMS transducer, and save the production cost. The MEMS transducer has the advantages of high integration level, high precision and small volume, and also has the application capability of phase control scanning.

The manufacturing method of the MEMS transducer comprises the following steps:

in a first step, as shown in fig. 2 and 3, a plurality of cavities 1101 are etched on an SOI substrate 1100, and each cavity 1101 is filled with PSG (phosphosilicate Glass). Fig. 2 is a top view of a cavity 1101 etched in a substrate 1100, where the circle in fig. 2 is the cavity 1101 and the black area in the circle is the PSG filled in the cavity 1101. Fig. 3 is a cross-sectional view of etching a cavity 1101 in a substrate 1100, the area recessed in the substrate 1100 being the cavity 1101, and the black area in the cavity 1101 being PSG filled in the cavity 1101.

In a second step, as shown in fig. 4 and 5, a lower electrode layer 1210 is formed over the substrate 1100 after the plurality of cavities 1101 are formed, and a plurality of first sub-electrodes 1211 are etched in the lower electrode layer 1210. The material of the bottom electrode layer 1210 includes, but is not limited to, molybdenum, tungsten, gold, aluminum, copper, etc. A set of first holes 1271 is formed in each of the plurality of first sub-electrodes 1211, thereby forming a plurality of sets of first holes 1271.

Fig. 4 is a top view of a lower electrode layer 1210 and a plurality of first sub-electrodes 1211 formed on a substrate 1100. In fig. 4, a lower electrode layer 1210 is formed over a substrate 1100, three first sub-electrodes 1211 are formed in the lower electrode layer 1210, each first sub-electrode 1211 is located corresponding to one cavity 1101, and the slanted stripe regions are three first sub-electrodes 1211 etched in the lower electrode layer 1210. In fig. 4, a set of first holes 1271 is formed in each first sub-electrode 1211, that is, two first holes 1271 are formed in each first sub-electrode 1211, two small circles in each first sub-electrode 1211 are respectively two first holes 1271, and a black area inside the small circle is the PSG filled in the cavity 1101.

Fig. 5 is a cross-sectional view of a lower electrode layer 1210 and a plurality of first sub-electrodes 1211 formed on a substrate 1100. In fig. 5, a lower electrode layer 1210 is formed over a substrate 1100, three first sub-electrodes 1211 are formed in the lower electrode layer 1210, each first sub-electrode 1211 is located corresponding to one cavity 1101, and the slanted stripe regions are three first sub-electrodes 1211 etched in the lower electrode layer 1210. In fig. 5, the horizontal line regions in the lower electrode layer 1210 are first holes 1271, a group of first holes 1271 (two first holes 1271) is formed in each of the first sub-electrodes 1211, and the black region in the cavity 1101 is the PSG filled in the cavity 1101.

Third, as shown in fig. 6 and 7, a piezoelectric layer 1220 is formed on the lower electrode layer 1210, and the material of the piezoelectric layer 1220 includes, but is not limited to, aluminum nitride AlN, zinc oxide ZnO, lead zirconate titanate PZT, PVDF, and the like. A plurality of sets of second apertures 1272 are formed in the piezoelectric layer 1220, the positions of the plurality of sets of second apertures 1272 corresponding one-to-one to the positions of the plurality of sets of first apertures 1271, i.e., the position of each set of second apertures 1272 corresponds to one set of first apertures 1271, and the position of each second aperture 1272 in each set of second apertures 1272 corresponds to the position of a first aperture 1271 in one set of first apertures 1271. A lower electrode pin hole 1212 of each first sub-electrode is also formed in the piezoelectric layer 1220.

Fig. 6 is a top view of a piezoelectric layer 1220 formed over a lower electrode layer 1210. In fig. 6, the diamond-patterned area is a piezoelectric layer 1220. The black circles in the piezoelectric layer 1220 are the second holes 1272 and the black areas are the PSGs filled in the cavities 1101. The position of each second hole 1272 in fig. 6 corresponds to the position of one first hole 1271. In the piezoelectric layer 1220, the circles of the slanted stripes are the lower electrode pin holes 1212 of each first sub-electrode. The bottom electrode pin holes 1212 of each first sub-electrode serve to pad the metal pins 1250 for the subsequent fabrication of each transducer element 1260.

As can be seen from fig. 4 and 5, the second first sub-electrode 1211 and the third first sub-electrode 1211 are connected together from left to right. Therefore, in fig. 6, the second bottom electrode pin hole 1212 is the bottom electrode pin hole 1212 of the second first sub-electrode 1211 and the third first sub-electrode 1211, counted from left to right.

Fig. 7 is a cross-sectional view of a piezoelectric layer 1220 formed over a lower electrode layer 1210. In fig. 7, the diamond-patterned area is a piezoelectric layer 1220, and the piezoelectric layer 1220 is formed on the lower electrode layer 1210. In the piezoelectric layer 1220, the area of the void is the second aperture 1272. The position of each second aperture 1272 in fig. 7 corresponds to the position of one first aperture 1271, and each set of first apertures 1271 corresponds to a set of second apertures 1272. In fig. 7, the diagonal grid of stripes in the piezoelectric layer 1220 is the lower electrode pin hole 1212 of each first sub-electrode.

In a fourth step, as shown in fig. 8 and 9, an upper electrode layer 1230 is formed on the piezoelectric layer 1220, and a plurality of second sub-electrodes 1231 are etched in the upper electrode layer 1230. Materials of the upper electrode layer 1230 include, but are not limited to, aluminum nitride AlN, zinc oxide ZnO, lead zirconate titanate PZT, PVDF, and the like. The position of each second sub-electrode 1231 corresponds to the position of one first sub-electrode 1211. A set of third holes 1273 is formed in each of the plurality of second sub-electrodes 1231, thereby forming a plurality of sets of third holes 1273.

Fig. 8 is a top view of an upper electrode layer 1230 and a plurality of second sub-electrodes 1231 formed over the piezoelectric layer 1220. In fig. 8, the diamond-patterned region is a piezoelectric layer 1220, and an upper electrode layer 1230 is formed on the piezoelectric layer 1220. Three second sub-electrodes 1231 are formed in the upper electrode layer 1230, the position of each second sub-electrode 1231 corresponds to the position of one first sub-electrode 1211, and the black and white corrugated regions are three second sub-electrodes 1231 etched in the upper electrode layer 1230. A set of third holes 1273 is formed in each second sub-electrode 1231, that is, two third holes 1273 are formed in each second sub-electrode 1231, two small circles in each second sub-electrode 1231 are respectively the two third holes 1273, and a black region inside the small circle is the PSG filled in the cavity 1101. The circles of the slanted stripes are the lower electrode pin holes 1212 of each first sub-electrode.

Fig. 9 is a cross-sectional view of forming an upper electrode layer 1230 and a plurality of second sub-electrodes 1231 over the piezoelectric layer 1220. In fig. 9, an upper electrode layer 1230 is formed on the piezoelectric layer 1220, three second sub-electrodes 1231 are formed in the upper electrode layer 1230, the position of each second sub-electrode 1231 corresponds to the position of one first sub-electrode 1211, and the black and white corrugated regions are three second sub-electrodes 1231 etched in the upper electrode layer 1230. In fig. 9, the horizontal line region in the upper electrode layer 1230 is the third holes 1273, a group of the third holes 1273 (two third holes 1273) is formed in each of the first sub-electrodes 1211, and the black region in the cavity 1101 is the PSG filled in the cavity 1101. The diagonal grid of lines in the piezoelectric layer 1220 is the bottom electrode pin hole 1212 of each first sub-electrode.

In a fifth step, as shown in fig. 10 and 11, a passivation layer 1240 is formed on the upper electrode layer 1230, and the material of the passivation layer 1240 includes, but is not limited to, SiO2, AlN aluminum nitride, and the like. And the lower electrode pin holes 1212 and the upper electrode pin holes 1232 of each of the first and second sub-electrodes, and the plurality of sets of fourth holes 1274 are formed in the passivation layer 1240, wherein the positions of the plurality of sets of fourth holes 1274 correspond to the positions of the plurality of sets of third holes 1273 one-to-one, that is, the position of each set of fourth holes 1274 corresponds to one set of third holes 1273, and the position of each fourth hole 1274 of each set of fourth holes 1274 corresponds to the position of the third hole 1273 of one set of third holes 1273.

Fig. 10 is a top view of passivation layer 1240 formed over upper electrode layer 1230. In fig. 10, two slanted stripe circles are the lower electrode pin holes 1212 of each first sub-electrode, and two black and white stripe circles are the upper electrode pin holes 1232 of each second sub-electrode. The black circles are the fourth holes 1274 and black is the PSG filled in the cavity 1101.

As can be seen from fig. 8 and 9, the second sub-electrode 1231 of the second array element is connected to the second sub-electrode 1231 of the third array element, as counted from left to right. Therefore, as shown in fig. 10, the second upper electrode pin hole 1232 is the second sub-electrode 1231 of the second array element and the upper electrode pin hole 1232 of the second sub-electrode 1231 of the third array element from left to right.

Fig. 11 is a cross-sectional view of a passivation layer 1240 formed over the upper electrode layer 1230. In fig. 11, a passivation layer 1240 is formed over the upper electrode layer 1230, and a lower electrode pin hole 1212 of each first sub-electrode and an upper electrode pin hole 1232 of each second sub-electrode are formed in the passivation layer 1240. In the passivation layer 1240, the diagonal lattice of stripes is the lower electrode pin hole 1212 of each first sub-electrode, and the black and white lattice of stripes is the upper electrode pin hole 1232 of each second sub-electrode. A plurality of sets of fourth holes 1274 are also formed in the passivation layer 1240, and the white lattices in the passivation layer 1240 are the fourth holes 1274, and the position of each fourth hole 1274 corresponds to the position of one third hole 1273.

Sixth, the PSG in cavity 1101 is released through each release hole 1270, and metal leads 1250 of each transducer element 1260 are routed, resulting in the MEMS transducer shown in fig. 1. Wherein a release hole 1270 is formed through each first hole 1271 and the second, third and

fourth holes

1272, 1273 and 1274 corresponding to the first hole 1271. A transducer element 1260 is formed by a first sub-electrode 1211 and a second sub-electrode 1231 corresponding to the position of the first sub-electrode 1211, and the piezoelectric layer 1220. The metal leads 1250 of a transducer element 1260 are formed by the lower electrode lead aperture 1212 of a first sub-electrode and the upper electrode lead aperture 1232 of the second sub-electrode 1231 corresponding to the position of the first sub-electrode 1211.

FIG. 12 is a schematic layout of a MEMS transducer made by the above steps. In fig. 12, the slanted striated circles are the lower electrode pin holes 1212 of each first sub-electrode, the black and white striated circles are the upper electrode pin holes 1232 of each second sub-electrode, and the white circles are the release holes 1270. Wherein each lower electrode pin hole 1212 and each upper electrode pin hole 1232 represents a metal pin 1250 for each transducer element 1260. The first wire is connected to the first upper electrode pin hole 1232, one end of the second wire is connected to the first lower electrode pin hole 1212, the other end of the second wire is connected to the second upper electrode pin hole 1232, and the third wire is connected to the second lower electrode pin hole 1212, forming a circuit.

In the circuit, a second transducer element 1260 is connected with a third transducer element 1260 in parallel, and the first transducer element 1260 is connected with the second transducer element 1260 and the third transducer element 1260 in series integrally. In fig. 1, from left to right, the first sub-electrode 1211, the first second sub-electrode 1231 and the piezoelectric layer 1220 form a first transducer element 1260, the second first sub-electrode 1211, the second sub-electrode 1231 and the piezoelectric layer 1220 form a second transducer element 1260, and the third first sub-electrode 1211, the third second sub-electrode 1231 and the piezoelectric layer 1220 form a third transducer element 1260.

In the embodiment, under the MEMS process, the serial and parallel manufacture of a plurality of transducers is completed on one MEMS chip. Through the development of the MEMS technology, the consistency of a plurality of transducer array elements 1260 in the MEMS transducer is easy to realize, the transducer array elements 1260 are accurately arranged according to the required positions to manufacture the MEMS transducer, and the production cost can be greatly reduced. The MEMS transducer can meet the requirements of different beam angles, sound pressure levels or sensitivities, the performance of the MEMS transducer is enriched and improved, the working efficiency of the MEMS transducer is improved, the MEMS transducer has the advantages of high integration level, high precision and small size, and the MEMS transducer is provided with the application capability of phase control scanning.

the present embodiments provide a MEMS transducer, comprising: the array antenna comprises a substrate and a thin film structure positioned on the substrate, wherein the thin film structure comprises a plurality of transducer elements, any two transducer elements in the transducer elements are electrically connected, the substrate comprises a plurality of cavities, and the positions of the cavities correspond to the positions of the transducer elements one by one. Through the MEMS transducer of this embodiment, realized on a MEMS chip, design a plurality of transducer array elements to arrange the arrangement with a plurality of transducer array elements as required, and with a plurality of transducer array elements circuit of different connected modes of formation as required, reach the demand according to different beam angles, sound pressure level and sensitivity, promote the performance and the work efficiency of MEMS transducer, practice thrift manufacturing cost. The MEMS transducer has the advantages of high integration level, high precision and small volume, and also has the application capability of phase control scanning.

Example two

Based on the same inventive concept, a second embodiment of the present invention further provides a method for manufacturing a MEMS transducer, as shown in fig. 13, including:

s201, forming a plurality of cavities in a substrate;

s202, forming a thin film structure on the substrate after the formation of the plurality of cavities, and forming a plurality of transducer elements in the thin film structure in the process of forming the thin film structure, wherein any two transducer elements in the plurality of transducer elements are electrically connected, and the positions of the plurality of cavities correspond to the positions of the plurality of transducer elements one to one.

As an alternative embodiment, the thin-film structure comprises: a lower electrode layer, a piezoelectric layer, and an upper electrode layer;

forming the piezoelectric layer over the lower electrode layer;

forming the upper electrode layer over the piezoelectric layer.

As an alternative embodiment, the thin film structure further comprises a passivation layer;

the passivation layer is formed over the upper electrode layer.

As an alternative embodiment, forming a plurality of transducer elements in the thin-film structure during the forming of the thin-film structure includes:

and obtaining the plurality of transducer elements through the plurality of first sub-electrodes and the plurality of second sub-electrodes, wherein one transducer element is formed by one first sub-electrode and the second sub-electrode corresponding to the position of the first sub-electrode.

As an alternative embodiment, after forming the piezoelectric layer on the lower electrode layer and before forming the upper electrode layer on the piezoelectric layer, the method further includes:

Since the method for manufacturing the MEMS transducer described in this embodiment is a method for manufacturing the MEMS transducer in the first embodiment of this application, based on the MEMS transducer described in the first embodiment of this application, a person skilled in the art can understand a specific implementation manner of the method for manufacturing the MEMS transducer in this embodiment and various variations thereof, and therefore, a detailed description of how to implement the MEMS transducer in the first embodiment of this application is omitted here. The method for fabricating the MEMS transducer according to the first embodiment of the present application is within the scope of the present application.

It should be apparent to those skilled in the art that while the preferred embodiments of the present invention have been described, additional variations and modifications in these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A MEMS transducer, comprising: the array antenna comprises a substrate and a thin film structure positioned on the substrate, wherein the thin film structure comprises a plurality of transducer elements, any two transducer elements in the transducer elements are electrically connected, the substrate comprises a plurality of cavities, and the positions of the cavities correspond to the positions of the transducer elements one by one.

2. The MEMS transducer of claim 1, wherein the membrane structure comprises: a lower electrode layer, a piezoelectric layer, and an upper electrode layer;

the lower electrode layer is located on the substrate, the piezoelectric layer is located on the lower electrode layer, and the upper electrode layer is located on the piezoelectric layer, wherein the lower electrode layer includes a plurality of first sub-lower electrodes, the upper electrode layer includes a plurality of second sub-upper electrodes, positions of the plurality of first sub-upper electrodes correspond to positions of the plurality of second sub-upper electrodes one to one, and one transducer array is formed by one first sub-upper electrode, one second sub-upper electrode corresponding to the position of the first sub-upper electrode, and the piezoelectric layer.

3. The MEMS transducer of claim 2, wherein the thin film structure further comprises a passivation layer and a metal pin of each of the plurality of transducer elements; the passivation layer is located over the upper electrode layer, and the metal pins of each transducer element are disposed in the passivation layer.

4. The MEMS transducer of claim 1, wherein the means for electrically connecting any two transducer elements comprises a series connection or a parallel connection.

5. The MEMS transducer of claim 1, wherein the membrane structure further comprises a plurality of sets of release holes, the plurality of sets of release holes having positions corresponding one-to-one to the positions of the plurality of cavities.

6. A method of fabricating a MEMS transducer, comprising:

forming a plurality of cavities in a substrate;

7. The method of claim 6, wherein the thin film structure comprises: a lower electrode layer, a piezoelectric layer, and an upper electrode layer;

forming the piezoelectric layer over the lower electrode layer;

forming the upper electrode layer over the piezoelectric layer.

8. The method of claim 7, wherein the thin film structure further comprises a passivation layer;

the passivation layer is formed over the upper electrode layer.

9. The method of manufacturing of claim 8, wherein forming a plurality of transducer elements in the thin film structure during the forming of the thin film structure comprises:

forming a plurality of second sub-electrodes in the upper electrode layer after forming the upper electrode layer over the piezoelectric layer, wherein positions of the plurality of first sub-electrodes correspond to positions of the plurality of second sub-electrodes one-to-one;

10. The method of claim 9, wherein after forming the piezoelectric layer over the lower electrode layer and before forming the upper electrode layer over the piezoelectric layer, further comprising: