CN111918188B

CN111918188B - MEMS loudspeaker and manufacturing process thereof

Info

Publication number: CN111918188B
Application number: CN202010663564.9A
Authority: CN
Inventors: 朱国; 程诗阳; 吴健兴; 但强; 李杨
Original assignee: AAC Technologies Holdings Nanjing Co Ltd
Current assignee: AAC Technologies Holdings Nanjing Co Ltd
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2021-12-14
Anticipated expiration: 2040-07-10
Also published as: CN111918188A; WO2022007046A1

Abstract

The invention provides an MEMS loudspeaker and a manufacturing process thereof, the MEMS loudspeaker comprises a substrate, a piston plate, a driving assembly and a flexible guide piece, wherein the substrate is provided with a cavity, the piston plate is movably arranged in the cavity, the driving assembly is connected to the piston plate and used for driving the piston plate to reciprocate along the cavity, the flexible guide piece and the piston plate form an integrated structure, and the flexible guide piece is arranged between the substrate and the piston plate and used for enabling the piston plate to move along a preset path. The flexible guide piece and the piston plate form an integrated structure, so that the MEMS loudspeaker is simpler in structure, the flexible guide piece and the piston plate can be synchronously molded, and the manufacturing process is facilitated to be simplified.

Description

MEMS loudspeaker and manufacturing process thereof

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of loudspeakers, in particular to a loudspeaker and a manufacturing process thereof.

[ background of the invention ]

The MEMS loudspeaker is a micro loudspeaker designed based on an MEMS process platform and has the advantages of small structure, low power consumption and the like.

There are two main types of MEMS speakers, one is a diaphragm vibration sounding type, and the other is a piston type. For the first kind of MEMS loudspeaker, the vibration of the diaphragm is used for emitting sound, for the second kind of MEMS loudspeaker, the driver drives the piston plate to reciprocate to emit sound, and the MEMS loudspeaker of the form converts the traditional parabolic deformation of the diaphragm into the up-and-down reciprocating motion of the piston plate so as to improve the volume of air pushed by the piston and optimize the sound emission quality.

For the second MEMS speaker, it is necessary to ensure a certain stability and reliability of the piston plate during the movement of the piston plate, so that some MEMS speakers in the related art use the elastic action of the elastic member to normalize the movement stroke of the piston plate by connecting the elastic member to the piston plate, but the elastic member and the piston plate are two independent components, which results in that the MEMS speaker tends to be complicated in structure and the manufacturing process of the MEMS speaker becomes complicated.

Therefore, there is a need for a MEMS speaker with simple structure and simple process.

[ summary of the invention ]

The invention aims to provide an MEMS loudspeaker and a manufacturing process thereof, which can realize the purposes of simplifying the structure and simplifying the manufacturing process under the condition of ensuring stability and reliability.

The technical scheme of the invention is as follows:

according to a first aspect, there is provided in an embodiment a MEMS speaker comprising:

a base having an inner wall that encloses a cavity;

the piston plate is movably arranged in the cavity, and the piston plate and the inner wall of the base are arranged at intervals;

a drive assembly connected to the piston plate for driving the piston plate to reciprocate within the cavity;

and a flexible guide, the flexible guide and the piston plate forming an integrated structure, and the flexible guide being fixed with an inner wall of the base to further fix the piston plate.

In some embodiments of the MEMS speaker, the flexible guides are a plurality of and are evenly spaced around the periphery of the piston plate.

In some embodiments of the MEMS speaker, the cavity is a cylindrical cavity, and the flexible guide and the piston plate together form a disc-shaped structure, and the flexible guide is an arc-shaped structure.

In some embodiments of the MEMS speaker, the cavity has a polygonal cross-section perpendicular to the moving direction of the piston plate, the integrated structure has a polygonal plate-shaped structure, and the flexible guide is at least one selected from a group consisting of a long strip structure, an i-shaped structure, a serpentine structure, a U-shaped structure, a zigzag structure, and an S-shaped structure.

In some embodiments of the MEMS speaker, the flexible guide is located on at least one side of the polygonal plate-like structure, and/or the flexible guide is located at least one corner of the polygonal plate-like structure.

In some embodiments of the MEMS speaker, the distance between the piston plate and the base is no greater than 0.1 mm.

In some embodiments of the MEMS speaker, the piston plate has a thickness greater than a thickness of the flexible guide, and a step is formed between the flexible guide and the piston plate.

In some embodiments of the MEMS speaker, the substrate has a notch in communication with the cavity, the flexible guide is disposed at an edge of the piston plate, the piston plate is proximate to an inner wall of the cavity, and the flexible guide is received in the notch.

In some embodiments of the MEMS speaker, the driving assembly includes a diaphragm disposed in the cavity and opposite the piston plate, and a piston plate connecting rod connected between the diaphragm and the piston plate, the diaphragm configured to generate a motive force to move the piston plate connecting rod, thereby actuating the piston plate.

In some embodiments of the MEMS speaker, the diaphragm and the piston plate link are fixedly connected by an elastic connector.

In some embodiments of the MEMS speaker, the diaphragm includes a piezoelectric layer and a structural layer, which are stacked, and the piezoelectric layer includes electrode material layers and a piezoelectric material layer located between the electrode material layers.

According to a second aspect, there is provided in an embodiment a process for manufacturing a MEMS speaker, comprising:

forming a first substrate by a deposition method;

partially etching the first base body from the upper surface of the first base body downwards to form a piston plate, a flexible guide piece and a first base which are arranged from inside to outside, forming a spacing gap and a connecting part between the piston plate and the flexible guide piece, forming an integrated structure by the piston plate and the flexible guide piece through the connecting part, and connecting the flexible guide piece to the first base;

forming a second base body by adopting a deposition method, wherein at least one part of the second base body from top to bottom forms a first part of vibrating diaphragm and a second base, and the second base is positioned on the periphery of the first part of vibrating diaphragm;

depositing a bottom electrode, a piezoelectric layer and a top electrode from the upper surface of the second substrate to form a piezoelectric actuator with a sandwich structure;

the second base body is partially etched from the lower surface of the second base body upwards to form a piston plate connecting rod and a cavity which are arranged from inside to outside, the first part of the vibrating diaphragm is released, the cavity is located on the periphery of the piston plate connecting rod, and the piezoelectric actuator and the first part of the vibrating diaphragm jointly form a driving assembly single body;

partially etching the single driving assembly body from the upper surface of the single driving assembly body downwards to form a notch communicated with the cavity and an elastic connecting piece distributed on the notch and used for connecting the single driving assembly body and the piston plate connecting rod;

connecting the etched second substrate to the etched first substrate through a bonding process;

etching the first substrate upwardly from a lower surface of the first substrate to release the piston plate, the flexible guide, and the first substrate, the first substrate and the second substrate forming a substrate, the cavity forming a cavity of the substrate, the first portion of the diaphragm and the piezoelectric actuator forming a diaphragm, the piston plate link, and the resilient connector forming a drive assembly.

In some embodiments of the MEMS speaker manufacturing process, a projection of the piston plate link in the up-down direction and a projection of the etched piezoelectric actuator in the up-down direction do not overlap.

The invention has the beneficial effects that: the flexible guide piece in the embodiment of the invention can enable the piston plate to move in the cavity along a preset path, so that the stability and reliability of the piston plate in the moving process can be improved, meanwhile, the flexible guide piece and the piston plate form an integrated structure, so that the MEMS loudspeaker is simpler in structure, the flexible guide piece and the piston plate can be synchronously molded, and the manufacturing process is facilitated to be simplified.

[ description of the drawings ]

FIG. 1 is a schematic diagram of a MEMS speaker according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a MEMS speaker in accordance with an embodiment of the present invention;

FIG. 3 is a cross-sectional view of a MEMS speaker according to another embodiment of the present invention;

FIG. 4 is an enlarged view of a portion of FIG. 3 at A;

FIG. 5 is a cross-sectional view of a MEMS speaker according to yet another embodiment of the present invention;

FIG. 6 is a partial enlarged view of FIG. 5 at B;

FIG. 7 is a cross-sectional view of a MEMS speaker in accordance with yet another embodiment of the present invention;

FIG. 8 is a cross-sectional view of a MEMS speaker in accordance with yet another embodiment of the present invention;

FIG. 9 is a cross-sectional view of a MEMS speaker in accordance with yet another embodiment of the present invention;

FIG. 10 is a cross-sectional view of a MEMS speaker in accordance with yet another embodiment of the present invention;

FIG. 11 is a cross-sectional view of a MEMS speaker in accordance with yet another embodiment of the present invention;

FIG. 12 is a flow chart of a process for manufacturing a MEMS speaker of the present invention;

FIG. 13 is a cross-sectional view of the MEMS speaker of FIG. 1;

FIG. 14 is a process step diagram of a MEMS speaker fabrication process of the present invention;

FIG. 15 is a process step diagram of another MEMS speaker fabrication process of the present invention;

fig. 16 is a process step diagram of a manufacturing process of a MEMS speaker according to yet another embodiment of the present invention.

Description of the main element symbols:

100-a substrate; 200-a piston plate; 300-a drive assembly; 400-a flexible guide; 500-an integrated structure; 101-a cavity; 102-an inner wall; 103-notch; 110-a first surface; 120-a second surface; 130-a first substrate; 140-a second substrate; 310-a diaphragm; 320-piston plate link; 330-elastic connecting piece; 340-notches; 311-a first part diaphragm; c-spacing gaps; a D-connecting part; e-step; f-a recessed region; 10-a first substrate; 20-a second substrate; 30-a piezoelectric actuator; 11-first substrate first layer; 12-a first substrate second layer; 13-first substrate third layer; 14-first matrix fourth layer; 15-first matrix fifth layer; 16-etching trace; 21-second substrate first layer; 22-a second substrate second layer; 23-second substrate third layer; 24-a second substrate fourth layer; 25-a cavity; 31-a drive assembly unit; 32-bottom electrode; 33-a piezoelectric layer; 34-top electrode.

[ detailed description ] embodiments

The invention is further described with reference to the following figures and embodiments.

Embodiments of the present invention provide an MEMS speaker (hereinafter, referred to as a "speaker"), which not only has a superior sound output effect, but also is simpler in structure.

In an embodiment of the present invention, referring to fig. 1-6, the speaker includes a base 100, a piston plate 200, a driving assembly 300, and a flexible guide 400.

The substrate 100 is formed with a cavity 101, the cavity 101 is enclosed by an inner wall 102 of the substrate 100, specifically, the substrate 100 has a first surface 110 and a second surface 120, the first surface 110 and the second surface 120 are oppositely disposed, and the cavity 101 extends from the first surface 110 to the second surface 120 and penetrates through the first surface 110 and the second surface 120.

The piston plate 200 is movably disposed in the cavity 101, and the piston plate 200 is spaced apart from the inner wall 102 of the base 100 such that the piston plate 200 can move in the cavity 101, and the speaker is sounded by the reciprocating movement of the piston plate 200 in the cavity 101.

The driving assembly 300 is disposed in the cavity 101 and connected to the piston plate 200, and the driving assembly 300 is used to generate a driving force and act on the piston plate 200 to reciprocate the piston plate 200 in the cavity 101.

The drive assembly 300 and the piston plate 200 are disposed opposite to each other for ease of understanding, and reference is not made to the first surface 110 and the second surface 120, but rather the piston plate 200 is understood to be disposed adjacent to the first surface 110, and the drive assembly 300 is disposed adjacent to the second surface 120.

The flexible guide 400 and the piston plate 200 form an integrated structure 500, and the flexible guide 400 is fixed to the inner wall 102 of the base 100 to further fix the piston plate 100, and the flexible guide 400 mainly functions as a guide for moving the piston plate 200 along a predetermined path.

For ease of understanding, the "preset path" is explained first herein. During the process of the drive assembly 300 driving the piston plate 200 to move within the cavity 101, the piston plate 200 is only moved by the driving force of the drive assembly 300, thereby causing the piston plate 200 to be likely to deviate from the path. Without taking the example that the cavity 101 is designed as a cylindrical cavity and the piston plate 200 is designed as a disc-shaped structure, it is better to make the piston plate 200 move along the axis of the cylindrical cavity in order to ensure the sound effect, and it is necessary to ensure that the plane of the piston plate 200 is perpendicular to the axis in the movement process, referring to fig. 1, it can be understood that the "preset path" means that when the piston plate 200 moves along the path, the piston plate 200 moves along the axis of the cylindrical cavity, and the plane of the piston plate 200 is perpendicular to the axis of the cylindrical cavity.

Of course, in other embodiments, when the specific structures of the cavity 101 and the piston plate 200 are changed, the meaning of "preset path" should be understood in conjunction with the specific case.

In addition, the "integrated structure 500" means that the flexible guide 400 and the piston plate 200 may be different functional components of the same component, and the flexible guide 400 is mainly used for ensuring the stability and reliability of the piston plate 200 during movement, in the case of the piston plate 200, which is mainly driven by the driving assembly 300. How the flexible guide 400 and the piston plate 200 form an integrated structure 500 will be developed in the embodiments below.

In the embodiment of the present invention, since the flexible guide 400 enables the piston plate 200 to move in the cavity 101 along a predetermined path, stability and reliability of the piston plate 200 during movement may be improved, and since the flexible guide 400 and the piston plate 200 form the integrated structure 500, a guide function of the flexible guide 400 and a movement sound generating function of the piston plate 200 may be integrated into one integrated structure 500, so that the MEMS speaker may be simpler in structure, and the flexible guide 400 and the piston plate 200 may be molded simultaneously, which is also advantageous in simplifying a manufacturing process.

In one embodiment, the integrated structure 500 formed by the piston plate 200 and the flexible guide 400 can be adapted to the shape of the cavity 101, and a large hollow space between the piston plate 200 and the cavity 101 can be effectively prevented, so as to improve the sound production effect.

For example, the cavity 101 is designed as a cylindrical cavity, and the piston plate 200 and the flexible guide 400 are jointly designed as a disc-shaped structure, so that when the piston plate 200 moves in the cylindrical cavity, the edge of the piston plate 200 can be closer to the inner wall of the cavity 101, thereby avoiding the influence on the sound effect caused by air leakage during the movement.

Further, in one embodiment, the flexible guide 400 is an arc-shaped structure that can be adapted to the shape of the edge of the piston plate 200 to facilitate forming the flexible guide 400.

In some specific embodiments, when the integrated structure 500 formed by the piston plate 200 and the flexible guide 400 is adapted to the shape of the cavity 101, the cross section of the cavity 101 along the direction perpendicular to the movement direction of the piston plate 200 may be polygonal, the piston plate 200 may be a polygonal plate-shaped structure, and the flexible guide 400 may be at least one selected from a group consisting of a long strip structure, an i-shaped structure, a serpentine structure, and a U-shaped structure.

It is understood herein that the cross-section of the cavity 101 may be triangular, quadrangular, pentagonal, etc., and accordingly, the piston plate 200 and the flexible guide 400 together form a triangular structure, a quadrangular structure, a pentagonal structure, etc. Compared to the integrated structure 500 of the disc-shaped structure, the polygonal plate-shaped structure has a straight side, so that the flexible guide 400 and the piston plate 200 can be more easily molded, and the flexible guide 400 can have various shapes, and even a combination of shapes. Further, the flexible guide 400 may be disposed to be located at least one side of the polygonal plate-shaped structure, and/or the flexible guide 400 may be disposed to be located at least one corner of the polygonal plate-shaped structure, for convenience of description and understanding, which will be described below by taking the piston plate 200 of the circular plate-shaped structure and the piston plate 200 of the quadrangular structure as examples.

For example, referring to fig. 2, the integrated structure 500 is a disc-shaped structure, the flexible guide 400 is formed at an edge of the disc-shaped structure, the flexible guide 400 and the piston plate 200 are different functional components of the same component, a separation gap C and a connection portion D are formed between the flexible guide 400 and the piston plate 200, the separation gap C is an arc-shaped gap, the connection portion D is located at one end of the separation gap C, the flexible guide 400 and the piston plate 200 are gradually separated from each other except the connection portion D during the movement of the piston plate 200, and the connection portion D provides a force perpendicular to the direction of the predetermined path to the piston plate 200, so as to prevent the piston plate 200 from deviating from the predetermined path during the movement, thereby achieving the guiding effect of the flexible guide 400 on the piston plate 200.

For another example, referring to fig. 7, the integrated structure 500 is a quadrilateral structure, a flexible guide 400 having a strip structure is formed on a long side of the quadrilateral structure, the flexible guide 400 and the piston plate 200 are different functional components of the same component, a separation gap C and a connection portion D are formed between the flexible guide 400 and the piston plate 200, the separation gap C encloses an "L" shape, the connection portion D is located at one corner of the separation gap C, the flexible guide 400 and the piston plate 200 are gradually separated from each other except the connection portion D during the movement of the piston plate 200, and the connection portion D provides a force perpendicular to the direction of the predetermined path to the piston plate 200 to prevent the piston plate 200 from deviating from the predetermined path during the movement, thereby achieving the guiding effect of the flexible guide 400 on the piston plate 200.

For another example, referring to fig. 8, the integrated structure 500 is a quadrilateral structure, a flexible guide 400 having an i-shaped structure is formed on a long side of the quadrilateral structure, the flexible guide 400 and the piston plate 200 are different functional components of the same component, a separation gap C and a connection portion D are formed between the flexible guide 400 and the piston plate 200, the separation gap C bends and turns into an i shape, the connection portion D is located at an end of the separation gap C, the flexible guide 400 and the piston plate 200 are gradually separated from each other except the connection portion D during the movement of the piston plate 200, and the connection portion D provides a force perpendicular to the direction of the predetermined path to the piston plate 200 to prevent the piston plate 200 from deviating from the predetermined path during the movement, thereby achieving the guiding effect of the flexible guide 400 on the piston plate 200.

For another example, referring to fig. 9, the integrated structure 500 is a quadrilateral structure, the flexible guide 400 is formed in a serpentine structure on a long side of the quadrilateral structure, the flexible guide 400 and the piston plate 200 are different functional components of the same component, a separation gap C and a connection portion D are formed between the flexible guide 400 and the piston plate 200, the separation gap C is in a cross shape, the connection portion D is located at an end of the separation gap C, the flexible guide 400 and the piston plate 200 are gradually separated from each other except the connection portion D during the movement of the piston plate 200, and the connection portion D provides a force perpendicular to the direction of the predetermined path for the piston plate 200, so as to prevent the piston plate 200 from deviating from the predetermined path during the movement, thereby achieving the guiding effect of the flexible guide 400 on the piston plate 200.

For another example, referring to fig. 10, the integrated structure 500 is a quadrilateral structure, the flexible guide 400 is formed in a U-shaped structure on a long side of the quadrilateral structure, the flexible guide 400 and the piston plate 200 are different functional components of the same component, a separation gap C and a connection portion D are formed between the flexible guide 400 and the piston plate 200, the separation gap C is U-shaped, the connection portion D is located at a middle position of the separation gap C, the flexible guide 400 and the piston plate 200 are gradually separated from each other except the connection portion D during the movement of the piston plate 200, and the connection portion D provides a force perpendicular to the direction of the predetermined path to the piston plate 200 to prevent the piston plate 200 from deviating from the predetermined path during the movement, thereby realizing the guiding effect of the flexible guide 400 on the piston plate 200.

In addition, the flexible guide 400 of the foregoing various structures may also be combined, for example, in the example shown in fig. 7, the flexible guide 400 of fig. 8, 9, 10 may be provided on the other long side, and vice versa. It should be understood that the present disclosure is only illustrative of possible embodiments of the flexible guide 400, and is not exhaustive, and in other embodiments, the flexible guide 400 may have more structures, such as a saw-tooth structure, an S-shaped structure, etc., or more combinations of the flexible guides 400.

In the above-described embodiment, the distance between the piston plate 200 and the base 100 is not more than 0.1mm (it can be understood that the distance between the portion of the piston plate 200 where the flexible guide 400 is not provided and the base 100 is provided, and the portion of the flexible guide 400 where the piston plate 200 is connected to the base 100 through the flexible guide 400 is provided), and the distance between the flexible guide 400 and the piston plate 200 is not more than 0.1mm (the size of the separation gap C in the foregoing description), which is advantageous in that not only the smooth movement of the piston plate 200 can be satisfied, but also excessive gaps are not left between the flexible guide 400 and the base 100, and between the flexible guide 400 and the piston plate 200, thereby improving the sound quality.

Of course, in addition to the above-mentioned embodiments, the piston plate 200 and the cavity 101 may not be designed to have a matching shape, and an unused space may be left between them, and in order to ensure the sound effect, other components or materials may be used to fill the space, so as to prevent the air from leaking widely or prevent the air from leaking completely.

In one embodiment, there is constant contact between the flexible guide 400 and the piston plate 200 over the course of the piston plate 200 movement.

In other words, as exemplified in the aforementioned example shown in fig. 2 and 7, although the spacing gap C is provided between the flexible guide 400 and the piston plate 200, the side wall of the flexible guide 400 and the side wall of the piston plate 200 are closely attached, and the flexible guide 400 and the piston plate 200 are not completely separated regardless of the movement of the piston plate 200, whereby air leakage due to the relative movement between the flexible guide 400 and the piston plate 200 can be prevented, thereby ensuring sound quality.

Further, in some embodiments, referring to fig. 3-4 in combination, the thickness of the piston plate 200 and the flexible guide 400 are different, and a step E is formed between the flexible guide 400 and the piston plate 200. Specifically, the thickness of the flexible guide 400 is smaller than that of the piston plate 200, and in the illustrated state, the flexible guide 400 is located at a position substantially in the middle of the piston plate 200 in the thickness direction, and a step E is formed on each of both sides of the flexible guide 400, and the step E on the upper side starts from the upper side of the piston plate 200 from top to bottom and ends at the upper side of the flexible guide 400, and the step E on the lower side starts from the lower side of the flexible guide 400 from top to bottom and ends at the lower side of the piston plate 200.

Thus, when the piston plate 200 moves in the cavity 101, it is not assumed that the piston plate 200 moves from bottom to top, and at this time, the piston plate 200 does not completely separate from the flexible guide 400 at least within a stroke defined between the upper side of the flexible guide 400 and the lower side of the piston plate 200, whereby air leakage can be prevented from occurring.

In other embodiments, referring to fig. 5-6 in combination, a step E is also formed between the flexible guide 400 and the piston plate 200. Specifically, in the illustrated state, the flexible guide 400 is located above the piston plate 200, and a step E is also formed on each side of the flexible guide 400, where the step E on the upper side starts from the upper side of the flexible guide 400 from top to bottom and ends at the upper side of the piston plate 200, and the step E on the lower side starts from the lower side of the flexible guide 400 from top to bottom and ends at the lower side of the piston plate 200.

Thus, when the piston plate 200 moves in the cavity 101, it is not assumed that the piston plate 200 moves from bottom to top, and at this time, the piston plate 200 does not completely separate from the flexible guide 400 at least in a stroke defined between the upper side of the flexible guide 400 and the lower side of the piston plate 200, whereby air leakage can be prevented from occurring.

In this other particular embodiment, it will be appreciated that, in comparison to the previous embodiments, the piston plate 200 has a longer stroke, which is more advantageous for improving the acoustic performance of the loudspeaker, while ensuring that the flexible guide 400 and the piston plate 200 do not completely separate.

In other specific embodiments, not shown in the drawings, the flexible guide 400 and the piston plate 200 may be combined in a wider variety of ways to avoid air leakage, for example, the thickness relationship between the flexible guide 400 and the piston plate 200 and the position relationship therebetween may be adjusted.

In one embodiment, the flexible guide 400 and the piston plate 200 are designed to be planar structures, so that interference between the flexible guide 400 and the piston plate 200 during the movement of the piston plate 200 can be prevented from affecting the smooth movement of the piston plate 200, and the smooth movement of the piston plate 200 can be maximally improved by combining the design that the distance between the piston plate 200 and the base 100 is not greater than 0.1mm and the distance between the flexible guide 400 and the piston plate 200 is not greater than 0.1 mm.

In one embodiment, referring to fig. 11, the base 100 has a notch 103 communicating with the cavity 101, and the flexible guide 400 is disposed at the edge of the piston plate 200, the piston plate 200 is adjacent to the inner wall of the cavity 101, and the flexible guide 400 is received in the notch 103.

Thus, by housing the flexible guide 400 in the base 100, more space can be provided for the piston plate 200, effectively increasing the vibration area of the piston plate 200, thereby improving acoustic performance.

In one embodiment, referring to fig. 2 and 7-10, the driving assembly 300 includes a diaphragm 310 and a piston plate connecting rod 320, the diaphragm 310 is disposed in the cavity 101 and opposite to the piston plate 200, the piston plate connecting rod 320 is connected between the diaphragm 310 and the piston plate 200, and the diaphragm 310 is used to generate a motive force to move the piston plate connecting rod 320, so as to drive the piston plate 200 to move.

In some embodiments, the diaphragm 310 or the piston plate 200 is disposed substantially parallel, and the piston plate connecting rod 320 is vertically connected between the diaphragm 310 and the piston plate 200, so that the piston plate connecting rod 320 drives the piston plate 200 to move with a uniform driving force.

Further, in some more specific implementations, the piston plate link 320 is disposed at a central location of the piston plate 200, while the number thereof may be more than one, for example, it may include a central piston plate link at the central location of the piston plate 200, and a plurality of peripheral piston plate links arranged at equal intervals and surrounding the central piston plate link, thereby allowing the piston plate link 320 to drive the piston plate 200 to move more evenly.

It is to be understood that, in the embodiment of the present invention, the specific structure of the piston plate link 320 is not limited, and for example, the cross section thereof may be various shapes such as a circle, a polygon, and the like.

In some specific embodiments, the diaphragm 310 includes a stacked piezoelectric layer and a structural layer, where the piezoelectric layer includes electrode material layers and a piezoelectric material layer located between the electrode material layers.

The electrode material layer can be made of Pt, Au or RuO2, the piezoelectric material layer can be made of PZT, ZnO, AlN or other piezoelectric materials, and the structural layer can be made of Si, SiO2, SiN or other materials.

The diaphragm 310 may vibrate when energized, thereby causing the piston plate 200 to move via the piston plate link 320, which causes the speaker to sound.

In some embodiments, referring to fig. 2, the diaphragm 310 and the piston plate link 320 are fixedly connected by an elastic connection 330.

The embodiment of the invention also provides a manufacturing process of the MEMS loudspeaker, which is mainly realized by a deposition method, an etching method and a bonding process, and the core in the whole manufacturing process is that the flexible guide piece 400 and the piston plate 200 can be integrally formed, so that the whole process is simplified.

Referring to fig. 12-14 in conjunction with the description below, in the relevant description, "upper" and "lower" are based on the orientation shown in the drawings, and for ease of description and understanding only, the manufacturing process may include the following steps:

s100, forming the first substrate 10 by adopting a deposition method.

In this step, it is first necessary to select suitable materials, for example, Si, SiO2 and a bonding metal, and then form the first substrate 10 with a multi-layer structure by step deposition, specifically, referring to fig. 13-14, first select material Si to form the first substrate first layer 11, then select material SiO2 to deposit on the first substrate first layer 11 to form the first substrate second layer 12, and then select material Si to deposit on the first substrate second layer 12 to form the first substrate third layer 13, or of course, directly select material SOI, which includes the first substrate first layer 11, the first substrate second layer 12, and the first substrate third layer 13; then the material SiO2 is selected and deposited on the first substrate third layer 13 to form the first substrate fourth layer 14, and finally the bonding metal is selected and deposited on the first substrate fourth layer 14 to form the first substrate fifth layer 15.

S200, partially etching the first base 10 from the upper surface of the first base 10 to form the piston plate 200, the flexible guide 400 and the first base 130 arranged from the inside to the outside, and forming a spacing gap C and a connection portion D between the piston plate 200 and the flexible guide 400, wherein the piston plate 200 and the flexible guide 400 form an integrated structure through the connection portion D, and the flexible guide 400 is connected to the first base 130.

In which step etching of the first substrate 10 formed in step S100 is required to reveal the contours of the corresponding structures. Referring to fig. 13-14, in this step, the first substrate 10 is partially etched, i.e., the first substrate 10 is etched from the upper surface thereof to the lower portion until the etching stops at the second layer 12 of the first substrate, and then a plurality of concave etching traces 16 are formed on the first substrate 10, once the etching traces 16 are penetrated, the spacing gaps C are formed (herein, the following step S800 may be combined), and the connecting portions D are located near the spacing gaps C and are not penetrated.

S300, forming a second base body 20 by adopting a deposition method, wherein at least one part of the second base body 20 from top to bottom forms a first part of diaphragm 311 and a second base 140, and the second base 140 is positioned on the periphery of the first part of diaphragm 311.

This step S300 can be performed with reference to the aforementioned step S100, and can be realized by step deposition. Specifically, referring to FIGS. 13-14, a bonding metal is selected to form the second substrate first layer 21, a material Si is selected to deposit the second substrate second layer 22 on the second substrate first layer 21, a material SiO2 is selected to deposit the second substrate third layer 23 on the second substrate second layer 22, and a material Si is selected to deposit the second substrate fourth layer 24 on the second substrate third layer 23. Of course, the second substrate may still be the SOI material as in step S100. In the second base 20 formed in a four-layer structure, the second base third layer 23 and the second base fourth layer 24 together form a first part diaphragm 311 and a second base 140, which are connected, and the second base 140 is located at the periphery of the first part diaphragm 311.

S400, depositing a bottom electrode 32, a piezoelectric layer 33 and a top electrode 34 from the upper surface of the second substrate 20 to form the piezoelectric actuator 30 with a sandwich structure.

The piezoelectric actuator 30 formed in a step deposition manner is required as a part of the final diaphragm 310 in this step S300. Specifically, the piezoelectric actuator 30 and the first part diaphragm 311 can jointly form the diaphragm 310 by first selecting electrode materials such as t, Au or RuO2 to form the bottom electrode 32 on the upper surface of the second substrate 20, then selecting piezoelectric materials such as PZT, ZnO, AlN to deposit the piezoelectric layer 33 on the bottom electrode 32, and finally selecting electrode materials such as t, Au or RuO2 to deposit the top electrode 34 on the piezoelectric layer 33.

S500, etching the second substrate 20 from the lower surface of the second substrate 20 upwards to form the piston plate connecting rod 320 and the cavity 25 arranged from inside to outside, and releasing the first part of the diaphragm 311, where the cavity 25 is located at the periphery of the piston plate connecting rod 320, and the piezoelectric actuator 30 and the first part of the diaphragm 311 together form the driving assembly unit 31.

In this step, the second substrate 20 needs to be etched step by step, please refer to fig. 13-14, when the second substrate 20 is etched, the etching process should start from the lower surface of the second substrate 20 and end at the third layer 23 of the second substrate, so as to form not only the piston plate connecting rod 320 and the cavity 25 arranged from inside to outside, but also release the first part of the diaphragm 311 in step S300, where the first part of the diaphragm 311 and the piezoelectric actuator 30 form the driving assembly unit 31.

It should be noted here that the order of the foregoing steps S400 and S500 may be changed, that is, S500 is executed first, and then S400 is executed.

S600, partially etching the driving assembly unit 31 from the upper surface of the driving assembly unit 31 downward to form a notch 340 communicating with the cavity 25 between the driving assembly unit 31 and the piston plate connecting rod 320, and an elastic connecting member 330 distributed on the notch 340 and connecting the piston plate connecting rod 320 and the driving assembly unit 31.

In this step, the driving assembly 300 having a certain structure can be formed. Referring to fig. 13-14, in step S500, the driving unit body 31 is etched downward from the upper surface thereof, the etching mainly extends around the piston plate connecting rod 320, and the driving unit body 31 is etched along the circumferential direction of the piston plate connecting rod 320, so as to form the notch 340 and the elastic connecting member 330 on the outer circumference of the piston plate connecting rod 320.

In some embodiments, referring to fig. 14, after the step S600 is performed, the projection of the piston plate link 320 in the up-down direction and the projection of the etched piezoelectric actuator 30 in the up-down direction may not overlap.

And S700, connecting the etched second substrate 20 to the etched first substrate 10 through a bonding process.

In this step, please refer to fig. 13-14 in combination, as mentioned above, for the first substrate 10, the fifth layer 15 of the first substrate is a top layer formed by the bonding metal, and for the second substrate 20, the first layer 21 of the second substrate is a bottom layer formed by the bonding metal, and at this time, the first layer 21 of the second substrate can be connected to the fifth layer 15 of the first substrate by the bonding action of the bonding metal, so as to connect the first substrate 10 and the second substrate 20.

S800, etching the first base 10 from the lower surface of the first base 10 to release the piston plate 200, the flexible guide 400 and the first substrate 130, the first substrate 130 and the second substrate 140 forming the substrate 100, the cavity 25 forming the cavity 101 of the substrate 100, the first portion diaphragm 311 and the piezoelectric actuator 30 forming the diaphragm 310, the piston plate link 320 and the elastic connection member 330 forming the driving assembly 300.

In this step, the first substrate 10 is first etched, and it is understood that the etching is performed on the lower surface of the first substrate 10, which is different from the etching performed on the first substrate 10 in the step S200, and the piston plate 200, the flexible guide 400 and the first base 130 are released through the gap C by etching the lower surface of the first substrate 10, and the etching process starts from the first substrate first layer 11 of the first substrate 10 and ends at the first substrate third layer 13.

It will be appreciated that a MEMS speaker can be formed after the aforementioned manufacturing process is performed, in which the piston plate 200 and the flexible guide 400 are simultaneously formed, which is simpler than the conventional process.

In addition, it can be understood that the speaker with various steps E can be formed by more detailed and reasonable design of the foregoing steps S200 and S800.

For example, referring to fig. 15, in step S800, the first substrate 10 is etched to a shallower depth, which does not completely etch the first layer 11 of the first substrate and does not reach the third layer 13 of the first substrate, thereby releasing the thicker piston plate 200, and forming a step E between the piston plate 200 and the flexible guide 400.

For another example, referring to fig. 16, in step S200, the first substrate 10 is etched in a relatively wide area, not only the etching traces 16 but also the concave regions F between the etching traces 11, so that the flexible guide 400 having a relatively thin thickness can be released, and in this case, in combination with step S700, a step E can be formed between the piston plate 200 and the flexible guide 400.

Finally, it should be noted that the manufacturing process in the embodiment of the present invention has no strict sequence, for example, steps S100 to S200 and steps S300 to S500 may be performed synchronously or separately, and step S200 may be completed before step S800 or after step S800.

While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.

Claims

1. A MEMS speaker, comprising:

a base having an inner wall that encloses a cavity;

and the flexible guide part and the piston plate form an integrated structure, the flexible guide part is fixed with the inner wall of the base to further fix the piston plate, the flexible guide part is used for guiding the piston plate and enabling the piston plate to move along a preset path, and the flexible guide part is a plurality of and is arranged at the periphery of the piston plate at uniform intervals.

2. The MEMS loudspeaker of claim 1, wherein the cavity is a cylindrical cavity, the flexible guide and the piston plate together forming a disc-like structure, the flexible guide being an arcuate structure.

3. The MEMS loudspeaker of claim 1, wherein the cavity has a polygonal cross-section taken perpendicular to the direction of motion of the piston plate, the unitary structure is a polygonal plate-like structure, and the flexible guide is at least one selected from the group consisting of a bar-shaped structure, an i-shaped structure, a serpentine structure, a U-shaped structure, a zigzag structure, and an S-shaped structure.

4. MEMS loudspeaker as claimed in claim 3, characterized in that the flexible guide is located on at least one side of the polygonal plate-like structure and/or that the flexible guide is located in at least one corner of the polygonal plate-like structure.

5. The MEMS loudspeaker of claim 1, wherein the distance between the piston plate and the base is no greater than 0.1 mm.

6. The MEMS speaker of claim 1, wherein the piston plate has a thickness greater than a thickness of the flexible guide, a step being formed between the flexible guide and the piston plate.

7. The MEMS speaker of claim 1, wherein the base has a notch in communication with the cavity, the flexible guide being disposed at an edge of the piston plate, the piston plate being proximate an inner wall of the cavity, the flexible guide being received within the notch.

8. The MEMS speaker of any one of claims 1-7, wherein the drive assembly includes a diaphragm disposed within the cavity and opposite the piston plate, and a piston plate linkage coupled between the diaphragm and the piston plate, the diaphragm configured to generate a motive force to move the piston plate linkage to actuate movement of the piston plate.

9. The MEMS loudspeaker of claim 8, wherein the diaphragm and the piston plate link are fixedly connected by an elastic connector.

10. The MEMS loudspeaker of claim 8, wherein the diaphragm comprises a piezoelectric layer and a structural layer stacked together, the piezoelectric layer having a three-layer structure and comprising electrode material layers and a piezoelectric material layer located between the electrode material layers.

11. A process for manufacturing a MEMS speaker, the process comprising:

forming a first substrate by a deposition method;

12. The manufacturing process of the MEMS speaker as claimed in claim 11, wherein a projection of the piston plate link in the up-down direction and a projection of the etched piezoelectric actuator in the up-down direction do not overlap.