CN118138971A - Sound production unit and manufacturing method thereof - Google Patents

Abstract

The invention discloses a sound generating unit and a manufacturing method of the sound generating unit, which relate to the technical field of digital speakers and are used for solving the problem that the sound pressure level of the sound generating unit is smaller because a vibrating diaphragm can only move towards a direction close to a fixed electrode, so that the displacement distance of the vibrating diaphragm is equal to the distance between the original position of the vibrating diaphragm and the fixed electrode. The sound generating unit includes: the electrode layer is arranged on the semiconductor substrate with the cavity, and a through hole penetrating through the electrode layer is formed in the electrode layer along the height direction of the electrode layer and is communicated with the cavity. The annular first supporting structure is arranged on the electrode layer, and the vibrating diaphragm structure is arranged on the annular first supporting structure. And a gap is reserved between the vibrating diaphragm structure and the electrode layer, the vibrating diaphragm structure comprises a vibrating diaphragm and a cantilever beam positioned on the periphery of the vibrating diaphragm, the vibrating diaphragm is arranged opposite to the through hole, and the annular second supporting structure is arranged on the vibrating diaphragm structure. The annular vibration stop layer is arranged on the annular second supporting structure, and a gap is reserved between the annular vibration stop layer and the vibrating diaphragm and used for blocking the vibrating diaphragm.

Description

Sound production unit and manufacturing method thereof

Technical Field

The invention relates to the technical field of digital loudspeakers, in particular to a sound generating unit and a manufacturing method of the sound generating unit.

Background

The sound generating unit is a common electroacoustic conversion device in the electroacoustic field, and plays an extremely important role in an electroacoustic system.

In the prior art, the core part of an electrostatic MEMS (Microelectro MECHANICAL SYSTEMS, microelectromechanical system) sound generating unit comprises an extremely thin diaphragm and a fixed electrode. The diaphragm is generally made of a conductive material, and the diaphragm is only displaced towards the fixed electrode under the action of an electric field, so that vibration and sound are produced.

However, since the diaphragm can only move in a direction approaching the fixed electrode, the displacement distance of the diaphragm is equal to the distance between the original position of the diaphragm and the fixed electrode, resulting in a small sound pressure level of the electrostatic MEMS sound generating unit.

Disclosure of Invention

The invention aims to provide a sound generating unit and a manufacturing method of the sound generating unit, which are used for improving the sound pressure level of the sound generating unit.

In order to achieve the above object, in a first aspect, the present invention provides a sound generating unit. The sound generating unit includes: the device comprises a semiconductor substrate, an electrode layer, an annular first supporting structure, a vibrating diaphragm structure, an annular second supporting structure and an annular vibration stopping layer. The semiconductor substrate is provided with a cavity, and the electrode layer is arranged on the semiconductor substrate. Along the height direction of the electrode layer, at least one through hole is formed in the electrode layer, the through hole penetrates through the electrode layer, and the through hole is communicated with the cavity and is arranged oppositely. The annular first supporting structure is arranged on the electrode layer, and the vibrating diaphragm structure is arranged on the annular first supporting structure. And a gap is reserved between the vibrating diaphragm structure and the electrode layer, the vibrating diaphragm structure comprises a vibrating diaphragm and a cantilever beam positioned on the periphery of the vibrating diaphragm, and the vibrating diaphragm is arranged opposite to the through hole. The annular second supporting structure is arranged on the vibrating diaphragm structure, and the annular vibration stopping layer is arranged on the annular second supporting structure. And a gap is reserved between the annular vibration stopping layer and the vibrating diaphragm, and the annular vibration stopping layer is used for blocking the vibrating diaphragm.

In the sounding unit provided by the invention, a gap is formed between the vibrating diaphragm structure and the electrode layer, a gap is formed between the annular vibration stopping layer and the vibrating diaphragm, and the annular vibration stopping layer is used for blocking the vibrating diaphragm. In the actual use process, the vibrating diaphragm of the vibrating diaphragm structure can move to the side close to the electrode layer and the side close to the annular vibration stopping layer. At this time, under the condition that the vibrating diaphragm of the vibrating diaphragm structure is ensured to work normally, and the moving distance of the vibrating diaphragm to the side close to the electrode layer is basically consistent or completely consistent or increased with the moving distance of the vibrating diaphragm to the side close to the electrode layer in the prior art, compared with the prior art, the total movement displacement of the vibrating diaphragm is increased, namely the vibration amplitude of the vibrating diaphragm is increased, so that the sound pressure level of the sound generating unit is improved.

In one implementation, the maximum distance between the two inner walls of the annular vibration stopping layer, which are relatively distributed and used for blocking the vibration film, is smaller than the minimum distance between the two side walls of the annular vibration stopping layer, which are relatively distributed; the annular vibration stop layer is non-conductive.

In one implementation, the via holes include a first via hole and a second via hole that communicate in a height direction of the electrode layer; the first through hole is positioned between the cavity and the second through hole;

The width of the first through hole is larger than that of the second through hole; the width direction of the first through hole and the width direction of the second through hole are perpendicular to the height direction of the electrode layer; and/or the depth of the first through hole is larger than the depth of the second through hole; the depth direction of the first through hole and the depth direction of the second through hole are consistent with the height direction of the electrode layer; and/or, along the height direction perpendicular to the electrode layer, one through hole comprises a plurality of second through holes which are distributed at intervals.

In one implementation, the sound generating unit further includes:

The insulating bulges are arranged on the electrode layer and face the vibrating diaphragm;

Gaps are formed between all the insulating protrusions and the vibrating diaphragm along the height direction of the electrode layer;

the insulation protrusions are distributed at intervals along the height direction perpendicular to the electrode layer, and the through holes and the insulation protrusions are distributed at intervals.

In one implementation, the sound generating unit further includes:

the first insulating layer is arranged on the electrode layer, and the insulating protrusions are arranged on the first insulating layer; the via hole penetrates through the electrode layer and the first insulating layer at the same time.

In a second aspect, the invention further provides a manufacturing method of the sound generating unit. The manufacturing method of the sounding unit comprises the following steps:

firstly, providing a semiconductor substrate and an electrode substrate; the electrode substrate has opposite first and second faces;

Next, along the height direction of the electrode substrate, a first through hole is formed in the first surface of the electrode substrate; the depth of the first through hole is smaller than the height of the electrode substrate, and the depth direction of the first through hole is consistent with the height direction of the electrode substrate;

Next, disposing a first face of the electrode substrate on the semiconductor substrate;

Next, a second through hole is formed in the second surface of the electrode substrate along the height direction of the electrode substrate, the first through hole is communicated with the second through hole, and the first through hole and the second through hole corresponding to the first through hole penetrate through the electrode substrate;

Next, forming a first sacrificial layer on the second surface of the electrode substrate and in the second through hole, and processing the first sacrificial layer to enable the first sacrificial layer to have a first stop groove; the first stopping groove is positioned at the periphery of the second through hole;

next, forming a vibrating diaphragm structure in the first sacrificial layer and the first stopping groove, processing the vibrating diaphragm structure to form a vibrating diaphragm and a cantilever beam positioned at the periphery of the vibrating diaphragm, wherein the first stopping groove is positioned at the periphery of the cantilever beam;

Next, forming a second sacrificial layer on the diaphragm structure, and processing the second sacrificial layer to enable the second sacrificial layer to have a second stop groove; the second stopping groove is positioned at the periphery of the cantilever beam;

Next, forming a vibration stopper layer in the second sacrificial layer and the second stopper groove, and processing the vibration stopper layer to form an annular vibration stopper layer;

Next, along the direction from the semiconductor substrate to the electrode substrate, forming a cavity in the semiconductor substrate, wherein the first through hole is communicated with the cavity and is oppositely arranged;

Then, removing the first sacrificial layer in the first stop groove to enable the vibrating diaphragm to be arranged opposite to the second through hole, wherein a gap is reserved between the vibrating diaphragm structure and the electrode substrate; and removing the second sacrificial layer in the second stop groove so that a gap is formed between the annular vibration stop layer and the vibrating diaphragm, and the annular vibration stop layer is used for blocking the vibrating diaphragm.

In the manufacturing method of the sounding unit provided by the invention, a gap is arranged between the vibrating diaphragm structure and the electrode substrate, a gap is arranged between the annular vibration stopping layer and the vibrating diaphragm, and the annular vibration stopping layer is used for blocking the vibrating diaphragm. In the practical use process, the vibrating diaphragm of the vibrating diaphragm structure can move to the side close to the electrode substrate and the side close to the annular vibration stopping layer. At this time, under the condition that the vibrating diaphragm of the vibrating diaphragm structure is ensured to work normally, and the moving distance of the vibrating diaphragm to the side close to the electrode substrate is basically consistent or completely consistent or increased with the moving distance of the vibrating diaphragm to the side close to the electrode layer in the prior art, compared with the prior art, the total movement displacement of the vibrating diaphragm is increased, namely the vibration amplitude of the vibrating diaphragm is increased, so that the sound pressure level of the sound generating unit is improved.

In one implementation, after the first surface of the electrode substrate is disposed on the semiconductor substrate, the method for manufacturing the sound generating unit further includes:

Forming a plurality of insulating protrusions on a second face of the electrode substrate, the insulating protrusions facing the diaphragm; a plurality of insulating protrusions are distributed at intervals along a height direction perpendicular to the electrode substrate;

after a second through hole is formed in the second surface of the electrode substrate, the first through hole and the second through hole are distributed with the insulating protrusions at intervals;

and after the first sacrificial layer in the first stopping groove is removed, gaps are reserved between all the insulating protrusions and the vibrating diaphragm along the height direction of the electrode substrate.

In one implementation, after forming a plurality of insulation protrusions on the second surface of the electrode substrate, the method for manufacturing the sound generating unit further includes:

Forming a first insulating layer on the electrode substrate and the insulating bump;

And forming a second through hole on the electrode substrate and the first insulating layer along the direction from the electrode substrate to the first insulating layer, wherein the first through hole and the second through hole corresponding to the first through hole penetrate through the electrode substrate and the first insulating layer.

In one implementation, the width of the first via is greater than the width of the second via; the width direction of the first through hole and the width direction of the second through hole are perpendicular to the height direction of the electrode substrate; and/or the number of the groups of groups,

The depth of the first through hole is larger than that of the second through hole; the depth direction of the first through hole and the depth direction of the second through hole are consistent with the height direction of the electrode substrate; and/or the number of the groups of groups,

One of the through holes includes a plurality of second through holes spaced apart in a height direction perpendicular to the electrode substrate.

In one implementation, the maximum distance between the two inner walls of the annular vibration stopping layer, which are relatively distributed and used for blocking the vibration film, is smaller than the minimum distance between the two side walls of the annular vibration stopping layer, which are relatively distributed; the annular vibration stop layer is non-conductive.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:

FIG. 1 is a cross-sectional view of a sound unit in an embodiment of the present invention;

FIG. 2 is an enlarged schematic view of a portion of the area of FIG. 1 in accordance with an embodiment of the present invention;

FIG. 3 is a cross-sectional view of a sound unit according to an embodiment of the present invention;

FIG. 4 is a second cross-sectional view of a sound unit according to an embodiment of the present invention;

FIG. 5 is a third cross-sectional view of a sound unit according to an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a sound unit according to an embodiment of the present invention;

FIG. 7 is a fifth cross-sectional view of a sound unit according to an embodiment of the present invention;

FIG. 8 is a sixth cross-sectional view of a sound unit according to an embodiment of the present invention;

FIG. 9 is a cross-sectional view seventh of a sound unit according to an embodiment of the present invention;

FIG. 10 is a cross-sectional view eighth of a sound unit according to an embodiment of the present invention;

FIG. 11 is a cross-sectional view of a sound unit according to an embodiment of the present invention;

Fig. 12 is a cross-sectional view of a sound unit according to an embodiment of the present invention.

Reference numerals:

1-semiconductor base, 10-cavity, 11-substrate, 12-second insulating layer, 2-electrode layer, 3-annular first supporting structure, 4-vibrating diaphragm structure, 40-vibrating diaphragm, 41-cantilever, 5-annular second supporting structure, 6-annular vibration stopping layer, 7-through hole, 70-first through hole, 71-second through hole, 8-insulating bump, 90-first insulating layer, 91-electrode base, 92-first sacrificial layer, 93-first stopping groove, 94-second sacrificial layer, 95-second stopping groove.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. The meaning of "a number" is one or more than one unless specifically defined otherwise.

In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc., are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

The component speaker has penetrated deeply into numerous market areas including, but not limited to, computer hardware, smartphones, various headset products, and internet of things (IoT) devices, and in recent years there has been a dramatic increase in demand for miniaturized, more cost-effective, lower energy consumption speaker solutions in the market, which has prompted the development and application of small-size and even miniature MEMS speaker technologies to accelerate the advancement and development.

In the prior art, the core part of the electrostatic MEMS sound generating unit comprises an extremely thin diaphragm and a fixed electrode. The diaphragm is generally made of a conductive material, and the diaphragm is only displaced towards the fixed electrode under the action of an electric field, so that vibration and sound are produced. The electrostatic MEMS sound unit has the advantages of high response speed and low distortion, which ensures high-definition audio experience, but the electrostatic MEMS speaker has certain difficulty in reaching enough sound pressure level and requires higher driving voltage.

Further, in the existing electrostatic MEMS sounding unit, the vibrating diaphragm is pulled by the electrostatic force to displace towards one side close to the fixed electrode, and the displacement distance of the vibrating diaphragm is equal to the distance between the original position of the vibrating diaphragm and the fixed electrode, so that the sound pressure level of the electrostatic MEMS sounding unit is smaller.

In order to solve the above technical problems, in a first aspect, an embodiment of the present invention provides a sound generating unit. Referring to fig. 1 and 2, the sound generating unit includes: a semiconductor substrate 1, an electrode layer 2, an annular first support structure 3, a diaphragm structure 4, an annular second support structure 5 and an annular vibration stop layer 6. The semiconductor substrate 1 has a cavity 10, and the electrode layer 2 is disposed on the semiconductor substrate 1. Along the height direction H1 of the electrode layer 2, at least one through hole 7 is formed in the electrode layer 2, the through hole 7 penetrates through the electrode layer 2, and the through hole 7 is communicated with the cavity 10 and is oppositely arranged. The annular first support structure 3 is arranged on the electrode layer 2, and the vibrating diaphragm structure 4 is arranged on the annular first support structure 3. The diaphragm structure 4 and the electrode layer 2 have a gap therebetween (because the diaphragm structure and the electrode layer have a gap therebetween, the diaphragm is convenient to move in a direction close to the electrode layer at this time), the diaphragm structure 4 includes a diaphragm 40 and a cantilever beam 41 located at the periphery of the diaphragm 40, and the diaphragm 40 is disposed opposite to the through hole 7. The annular second support structure 5 is arranged on the vibrating diaphragm structure 4, and the annular vibration stopping layer 6 is arranged on the annular second support structure 5. The annular vibration stopper layer 6 has a gap with the diaphragm 40 (since the annular vibration stopper layer and the diaphragm have a gap therebetween, the diaphragm is convenient to move in a direction approaching the annular vibration stopper layer at this time), and the annular vibration stopper layer 6 serves to block the diaphragm 40.

The cross section of the diaphragm may be rectangular, and the cantilever beams are located at four sides of the diaphragm. Or the cross section of the vibrating diaphragm can be in a five shape, and the cantilever beam is positioned at five sides of the vibrating diaphragm. Or the cross section of the vibrating diaphragm can be hexagonal, and the cantilever beam is positioned at the six sides of the vibrating diaphragm. Or the cross section of the diaphragm can be circular, and the cantilever beam is positioned at the periphery of the diaphragm.

Referring to fig. 1 and 2, in the sound generating unit provided by the embodiment of the present invention, a gap is formed between the diaphragm structure 4 and the electrode layer 2, a gap is formed between the annular vibration stopping layer 6 and the diaphragm 40, and the annular vibration stopping layer 6 is used for blocking the diaphragm 40. In actual use, the diaphragm 40 of the diaphragm structure 4 may move to the side close to the electrode layer 2 or to the side close to the annular vibration stopper layer 6. At this time, in the case that the diaphragm 40 of the diaphragm structure 4 is ensured to normally operate, and the distance of the diaphragm 40 moving toward the side close to the electrode layer 2 is substantially identical or completely identical or increased to the distance of the diaphragm moving toward the side close to the electrode layer in the prior art, the total movement displacement of the diaphragm 40 is increased, that is, the vibration amplitude of the diaphragm 40 is increased, compared with the prior art, so that the sound pressure level of the sound generating unit is improved.

As a possible implementation, referring to fig. 1, the above-mentioned semiconductor base 1 may include a substrate 11 and a second insulating layer 12.

Illustratively, the substrate may be made of polycrystalline silicon, monocrystalline silicon, silicon wafers (including sliced, lapped, polished wafers), epitaxial wafers, amorphous silicon films, microcrystalline silicon films, and the like. For example, the substrate may be a silicon substrate. The second insulating layer may be a silicon nitride layer.

As a possible implementation, referring to fig. 1, the cavity 10 may penetrate the semiconductor substrate 1 along the height direction H2 of the semiconductor substrate 1, or only one side of the semiconductor substrate 1 facing the electrode layer 2 may be opened to form the cavity 10 inside the semiconductor substrate 1.

As a possible implementation manner, the materials and the dimensions of the annular first support structure and the annular second support structure may be equal or unequal, and may be set according to actual needs in specific cases.

Referring to fig. 1, the annular first support structure 3 is used for supporting and fixing the diaphragm structure 4, so that a gap exists between the diaphragm structure 4 and the electrode layer 2. Specifically, the tip setting of vibrating diaphragm structure is on the electrode layer, and the middle region unsettled setting of vibrating diaphragm structure is in the electrode layer top. At this time, a gap is formed between the middle region of the diaphragm structure and the electrode layer, so that the diaphragm can move in a direction approaching to the electrode layer.

The above-mentioned annular second support structure 5 is used for supporting and fixing the annular vibration stopping layer 6, so that a gap is formed between the annular vibration stopping layer 6 and the diaphragm 40, and the annular vibration stopping layer 6 can stop the diaphragm 40 in motion under the condition that the diaphragm 40 is not affected to move (i.e. the normal operation of the diaphragm 40 is not affected, so as to ensure the normal sounding of the sounding unit), and the diaphragm 40 is stopped. Specifically, the annular vibration stopping layer is arranged at the end part of the vibrating diaphragm structure, a gap is reserved between the middle area of the vibrating diaphragm structure and the annular vibration stopping layer, and the vibrating diaphragm can move in the direction close to the annular vibration stopping layer conveniently.

As a possible implementation, see fig. 1, the maximum distance L1 between the two inner walls of the annular vibration stopper layer 6, which are relatively distributed and serve to block the diaphragm 40, is smaller than the minimum distance L2 between the two side walls of the diaphragm 40, which are relatively distributed, and the annular vibration stopper layer 6 is not conductive.

The shape of the annular vibration stopping layer may be a circular ring, a square ring, an elliptical ring or other shapes, and the shape of the annular first support structure and the annular second support structure are the same. The material for manufacturing the annular vibration stop layer can be selected according to practical situations, so long as the effect of blocking the vibrating diaphragm can be realized, and the annular vibration stop layer is not conductive.

As a possible implementation, further details regarding the structure of the diaphragm may be found in the prior art, and will not be described in detail here.

As a possible implementation, the electrode layer is bonded to the semiconductor substrate. Further, the number of the through holes formed in the electrode layer may be set according to the actual situation, and for example, the through holes may be one, two, three or more.

When the electrode layer is provided with a plurality of through holes, the plurality of through holes can be distributed in an array, linear, annular or rectangular mode. The shape of each through hole can be set according to actual requirements, and the through holes can be round through holes or square through holes or oval through holes.

As a possible implementation, referring to fig. 1 and 2, the through hole 7 includes a first through hole 70 and a second through hole 71 communicating in the height direction H1 of the electrode layer 2, the first through hole 70 being located between the cavity 10 and the second through hole 71.

The width W1 of the first through hole 70 is larger than the width W2 of the second through hole 71, and both the width direction of the first through hole 70 and the width direction of the second through hole 71 are perpendicular to the height direction of the electrode layer 2. Illustratively, the first via 70 has a width greater than or equal to 3 μm and less than or equal to 10 μm. For example, the width of the first through hole 70 may be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or the like.

Under the condition of adopting the technical scheme, the second through hole 71 is smaller in size so as to be convenient for the first sacrificial layer 92 to be filled, the process difficulty is reduced, and the damping of air circulation can be ensured to be smaller due to the larger size of the first through hole 70, so that the resistance of vibration of the vibrating diaphragm 40 is reduced. Further, the problem of the excessive spacing between the diaphragm 40 and the electrode layer 2 can be solved, thereby reducing the driving voltage and reducing the power and energy consumption.

The depth of the first through hole 70 is larger than the depth of the second through hole 71, and the depth direction of the first through hole 70 and the depth direction of the second through hole 71 are both identical to the height direction of the electrode layer 2. The first through hole 70 has a depth of 10 μm or more and 50 μm or less, for example. For example, the width of the first through hole 70 may be 10 μm, 14 μm, 20 μm, 26 μm, 30 μm, 34 μm, 40 μm, 45 μm, 50 μm, or the like.

The number of the second through holes 71 located above the first through holes 70 may be one, two or more within the same through hole. Illustratively, one via hole includes a plurality of second via holes 71 spaced apart in a direction perpendicular to the height direction of the electrode layer 2. For example, one via hole includes a plurality of second via holes spaced apart in a length direction of the electrode layer or in a horizontal direction.

As a possible implementation, referring to fig. 1 and 2, the sound generating unit further includes: a plurality of insulating projections 8. The plurality of insulating protrusions 8 are disposed on the electrode layer 2 and face the diaphragm 40. Along the height direction H1 of the electrode layer 2, all the insulating projections 8 have a gap with the diaphragm 40. The plurality of insulating protrusions 8 are spaced apart in a direction perpendicular to the height direction of the electrode layer 2, and the through holes 7 are spaced apart from the insulating protrusions 8. For example, a plurality of insulating protrusions are spaced apart along the length direction of the electrode layer or along the horizontal direction.

Under the condition of adopting the technical scheme, the insulating bulge 8 not only can prevent the vibrating diaphragm 40 from being bonded with the electrode layer 2, but also can prevent the vibrating diaphragm 40 from being short-circuited with the electrode layer 2 so as to ensure the normal operation of the sounding unit.

The insulating bump may be made of silicon nitride, for example. As for the dimensions of the above-described insulating projections, the spacing between adjacent two insulating projections may be set according to actual conditions, and is not particularly limited herein.

As a possible implementation manner, the sound generating unit includes a plurality of through holes, and the through holes and the insulation protrusions are alternately and alternately distributed at intervals along a height direction (e.g., a length direction of the electrode layer) perpendicular to the electrode layer.

In an alternative manner, referring to fig. 1 and 2, the sound generating unit further includes: a first insulating layer 90. The first insulating layer 90 is disposed on the electrode layer 2, the insulating bump 8 is disposed on the first insulating layer 90, and the through hole 7 penetrates through both the electrode layer 2 and the first insulating layer 90.

Under the condition of adopting the technical scheme, the first insulating layer 90 not only can further prevent the vibrating diaphragm 40 from being bonded with the electrode layer 2, but also can further prevent the vibrating diaphragm 40 from being shorted with the electrode layer 2 so as to ensure the normal operation of the sounding unit.

The material of the first insulating layer may be silicon nitride. As for the size of the first insulating layer, it may be set according to practical situations, and is not particularly limited herein.

In a second aspect, the embodiment of the invention further provides a manufacturing method of the sound generating unit. The manufacturing method of the sounding unit comprises the following steps:

first, referring to fig. 3 and 4, a semiconductor substrate 1 and an electrode substrate 91 are provided; the electrode substrate 91 has opposite first and second faces;

The semiconductor base may include a substrate and a second insulating layer, for example. The substrate may be made of polycrystalline silicon, monocrystalline silicon, silicon wafers (including sliced, lapped, polished), epitaxial wafers, amorphous silicon films, microcrystalline silicon films, and the like. For example, the substrate may be a silicon substrate. The second insulating layer may be a silicon nitride layer. The electrode substrate may be made of polycrystalline silicon, monocrystalline silicon, silicon wafers (including sliced wafers, lapped wafers, polished wafers), epitaxial wafers, amorphous silicon films, microcrystalline silicon films, and the like. For example, the electrode substrate may be a silicon electrode substrate.

Specifically, referring to fig. 3 and 4, a substrate 11 is provided, and a second insulating layer 12 is formed on the surface of the substrate 11. Next, an electrode substrate 91 is provided. In connection with the sound emitting unit provided in the first aspect, the electrode substrate 91 herein is used to form an electrode layer of the sound emitting unit in the first aspect. In view of this, it should be noted that although the reference numerals of the partial structures in fig. 2 to 12 are not identical to those in fig. 1, in order to facilitate understanding of the formation process of each structure when actually manufacturing the sound generating unit, the structure finally formed by the above manufacturing method is the structure shown in fig. 1.

Next, referring to fig. 4, a first through hole 70 is opened in a first surface of the electrode substrate 91 in a height direction of the electrode substrate 91; the depth of the first through hole 70 is smaller than the height of the electrode substrate 91, and the depth direction of the first through hole 70 is consistent with the height direction of the electrode substrate 91;

Illustratively, a plurality of first through holes are formed on the first surface of the electrode substrate, and the plurality of first through holes may be distributed in an array, a linear distribution, a circular distribution, a rectangular distribution, or the like. The shape of each first through hole can be set according to actual requirements, and the first through holes can be round first through holes or square first through holes or oval first through holes.

Specifically, the first surface of the electrode substrate 91 is subjected to photolithography and etching, so as to form a plurality of first through holes 70 distributed in an array on the first surface of the electrode substrate 91.

Next, referring to fig. 5, a first face of an electrode substrate 91 is disposed on the semiconductor substrate 1;

Illustratively, the first face of the electrode substrate 91 provided with the first through-hole 70 is bonded with the second insulating layer 12 included in the semiconductor substrate 1;

It should be noted that if the height of the electrode base is equal to the height of the electrode layer included in the sound emitting unit described in the first aspect actually manufactured later, the height of the electrode base is not subjected to the thinning process or the thickening process. If the height of the electrode substrate is greater than the height of the electrode layer included in the sound emitting unit described in the first aspect actually manufactured later, the second surface of the electrode substrate 91 is processed to thin the electrode substrate 91 to a height actually required. It should be noted that the depth of the first through hole is always smaller than the height of the thinned electrode substrate. I.e. when the first through hole is initially provided in the first side of the electrode substrate, the depth of the first through hole needs to be smaller than the height of the electrode layer comprised by the sound generating unit described in the first aspect.

In an alternative manner, referring to fig. 6, a plurality of insulating protrusions 8 are formed on the second face of the electrode substrate 91;

Illustratively, a third insulating layer is deposited on the second face of the electrode substrate 91, and is processed by a photolithography, etching process to form a plurality of insulating protrusions 8 on the second face of the electrode substrate 91. The plurality of insulating projections 8 are spaced apart in a direction perpendicular to the height direction of the electrode substrate 91. For example, a plurality of insulating protrusions are spaced apart along the length direction of the electrode substrate or along the horizontal direction. The insulating bump may be made of silicon nitride. As for the dimensions of the above-described insulating projections, the spacing between adjacent two insulating projections may be set according to actual conditions, and is not particularly limited herein.

In an alternative manner, referring to fig. 6, a first insulating layer 90 is formed on the electrode base 91 and the insulating projections 8; the above-described first insulating layer 90 completely covers the electrode base 91 and the insulating projections 8.

Next, referring to fig. 7, in the direction from the electrode substrate 91 to the first insulating layer 90, the second through-holes 71 are opened on the electrode substrate 91 and the first insulating layer 90, and the first through-holes 70 and the second through-holes 71 corresponding thereto penetrate through the electrode substrate 91 and the first insulating layer 90. The first through hole is communicated with the second through hole corresponding to the first through hole. The first insulating layer may be made of silicon nitride. As for the size of the first insulating layer, it may be set according to practical situations, and is not particularly limited herein.

Note that if the first insulating layer 90 and/or the insulating projections 8 are not formed, the second through holes 71 are opened in the second face of the electrode base 91 in the height direction of the electrode base 91, and the first through holes 70 and the second through holes 71 communicate; the first through-holes 70 and the second through-holes 71 corresponding thereto penetrate the electrode substrate 91 in the height direction of the electrode substrate 91.

For example, when the plurality of second through holes are formed on the electrode substrate and the first insulating layer through photolithography, etching processes, the plurality of second through holes may be distributed in an array, a linear, a circular, a rectangular, or the like. The shape of each second through hole can be set according to actual requirements, and the second through holes can be round second through holes or square second through holes or elliptic second through holes.

As a possible implementation, referring to fig. 7, the width of the first through hole 70 is greater than the width of the second through hole 71, and the width direction of the first through hole 70 and the width direction of the second through hole 71 are perpendicular to the height direction of the electrode layer 2. Illustratively, the first via 70 has a width greater than or equal to 3 μm and less than or equal to 10 μm. For example, the width of the first through hole 70 may be 3 μm,4 μm,5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or the like.

The depth of the first through hole 70 is larger than the depth of the second through hole 71, and the depth direction of the first through hole 70 and the depth direction of the second through hole 71 are both identical to the height direction of the electrode layer 2. The first through hole 70 has a depth of 10 μm or more and 50 μm or less, for example. For example, the width of the first through hole 70 may be 10 μm, 14 μm, 20 μm, 26 μm, 30 μm, 34 μm, 40 μm, 45 μm, 50 μm, or the like.

The number of the second through holes 71 located above the first through holes 70 may be one, two or more within the same through hole. Illustratively, one via hole includes a plurality of second via holes 71 spaced apart in a direction perpendicular to the height direction of the electrode layer 2. For example, one via hole includes a plurality of second via holes spaced apart in a length direction of the electrode layer or in a horizontal direction.

Next, referring to fig. 7 and 8, a first sacrificial layer 92 is formed on the second surface of the electrode substrate 91 and in the second through hole 71, and the first sacrificial layer 92 is processed such that the first sacrificial layer 92 has a first stop groove 93; the first stopping groove 93 is located at the periphery of the second through hole 71;

illustratively, a first sacrificial material is deposited on the second side of the electrode substrate 91 and within the second via 71 to form a first sacrificial layer 92. Next, the first sacrificial layer 92 is processed by photolithography, etching process to form a ring-shaped first stop groove 93.

Note that when the insulating bump 8 and the first insulating layer 90 are formed on the electrode substrate 91, the first sacrificial layer 92 is also formed on the insulating bump 8 and the first insulating layer 90, and the first sacrificial layer 92 is processed by photolithography, etching process to form the annular first stop groove 93. The ring may be circular, square, elliptical or other shape. Further, the first sacrificial layer 92 may be provided so as to close the second through hole 71, and the depth of the first sacrificial layer 92 in the second through hole 71 is not considered.

As a possible implementation manner, when the width of the first through hole 70 is greater than the width of the second through hole 71, the smaller size of the second through hole 71 facilitates the filling of the first sacrificial layer 92, which reduces the difficulty of the process, and the larger size of the first through hole 70 can ensure that the damping of the air circulation is smaller, thereby reducing the resistance of the vibration of the diaphragm 40. Further, the problem of the excessive spacing between the diaphragm 40 and the electrode layer 2 can be solved, thereby reducing the driving voltage and reducing the power and energy consumption.

It will be appreciated that in connection with the sound emitting unit provided in the first aspect, the first sacrificial layer 92 herein is used to form the annular first support structure 3 of the sound emitting unit in the first aspect.

Next, referring to fig. 8 and 9, the diaphragm structure 4 is formed in the first sacrificial layer 92 and the first stopping groove 93, the diaphragm structure 4 is processed to form the diaphragm 40 and the cantilever 41 located at the periphery of the diaphragm 40, and the first stopping groove 93 is located at the periphery of the cantilever 41; the diaphragm structure 4 has good electrical conductivity.

Illustratively, a material is deposited over the first sacrificial layer 92 and the first stop groove 93 to form the diaphragm structure 4. Next, the diaphragm structure 4 is processed through photolithography and etching processes to form slits, thereby forming the diaphragm 40 and the cantilever beam 41 located at the periphery of the diaphragm 40. The slit penetrates through the diaphragm structure 4 and is connected to the first sacrificial layer 92. The distance between the first stopping groove 93 and the diaphragm 40 may be set according to practical situations, and is not particularly limited herein, as long as the diaphragm structure 4 can be ensured to work normally. The cantilever beam 41 is positioned between the first stop groove 93 and the second through hole 71 adjacent to the cantilever beam 41.

Next, referring to fig. 9 and 10, a second sacrificial layer 94 is formed on the diaphragm structure 4, and the second sacrificial layer 94 is processed such that the second sacrificial layer 94 has a second stop groove 95; the second stop groove 95 is located at the periphery of the cantilever 41;

Illustratively, a second sacrificial material is deposited over the diaphragm structure 4 to form a second sacrificial layer 94. Next, the second sacrificial layer 94 is processed by photolithography, etching process to form a ring-shaped second stop groove 95. It will be appreciated that in connection with the sound emitting unit provided in the first aspect, the second sacrificial layer 94 herein is used to form the annular second support structure 5 of the sound emitting unit in the first aspect.

Next, referring to fig. 11, a vibration stopper layer is formed in the second sacrificial layer 94 and the second stopper groove 95, and the vibration stopper layer is processed to form an annular vibration stopper layer 6;

Illustratively, a material is deposited within the second sacrificial layer 94 and the second stop groove 95 to form a vibration stop layer. Next, the vibration stopper layer is processed by photolithography, etching process to form the annular vibration stopper layer 6.

Next, referring to fig. 12, in the direction from the semiconductor substrate 1 to the electrode substrate 91, a cavity 10 is opened in the semiconductor substrate 1, and a first through hole 70 is communicated with the cavity 10 and is disposed opposite thereto;

The semiconductor substrate 1 is illustratively processed by a photolithographic, etching process by flipping the structure already formed above. Specifically, a part of the substrate 11 and the second insulating layer 12 are removed to open the cavity 10 in the semiconductor base 1.

It should be noted that the cavity may extend through the semiconductor substrate in a direction from the semiconductor substrate to the electrode substrate, or only a side of the semiconductor substrate facing the electrode substrate may be opened to form a cavity within the semiconductor substrate (in this case, a bottom portion of the cavity extending completely through the semiconductor substrate may be closed to form a "trench" opened within the semiconductor substrate).

Next, referring to fig. 12 and 1, the first sacrificial layer 92 located in the first stopping groove 93 is removed so that the diaphragm 40 is disposed opposite to the second through hole 71 with a gap between the diaphragm structure and the electrode substrate; the second sacrificial layer 94 located in the second stop groove 95 is removed so that there is a gap between the annular vibration stop layer 6 and the diaphragm 40 (since there is a gap between the annular vibration stop layer 6 and the diaphragm 40, at this time, the diaphragm is facilitated to move in a direction approaching the annular vibration stop layer), the annular vibration stop layer 6 serves to block the diaphragm 40.

Illustratively, the structure that has been formed as described above is flipped over again, and the first sacrificial layer 92 surrounded by the first stop groove 93 is removed using a release process so that the diaphragm 40 is disposed opposite the second through hole 71 with a gap between the diaphragm structure and the electrode substrate. The second sacrificial layer 94 surrounded by the second stop groove 95 is removed so that there is a gap between the annular vibration stop layer 6 and the diaphragm 40.

The annular vibration stopper layer 6 is disposed in opposition to each other and serves to block the two inner walls of the diaphragm 40 from exceeding the slit position. As a possible implementation, the maximum distance L1 between the two inner walls of the annular vibration-stopping layer 6, which are relatively distributed and serve to block the diaphragm 40, is smaller than the minimum distance L2 between the two side walls of the diaphragm 40, which are relatively distributed; the annular vibration stop layer 6 is not conductive.

In connection with the foregoing, when the insulating projections 8 are formed, the insulating projections 8 face the diaphragm 40. After the first sacrificial layer located in the first stop groove is removed, all the insulating projections 8 have a gap with the diaphragm 40 in the height direction of the electrode substrate 91. After the second through holes are formed on the second surface of the electrode substrate, the first through holes 70 and the second through holes 71 are spaced apart from the insulating protrusions 8 in a direction perpendicular to the height direction of the electrode substrate 91. Further, when the insulating protrusions 8 are formed, the insulating protrusions 8 can not only prevent the diaphragm 40 and the electrode substrate 91 from being bonded together, but also prevent the diaphragm 40 and the electrode substrate 91 from being shorted together, so as to ensure the sound generating unit to work normally. Still further, when the first insulating layer 90 is formed, the first insulating layer 90 may further prevent not only the diaphragm 40 and the electrode layer 2 from being bonded together, but also the diaphragm 40 and the electrode layer 2 from being shorted together, so as to ensure the normal operation of the sound generating unit.

In the method for manufacturing the sound generating unit provided by the embodiment of the invention, a gap is formed between the diaphragm structure 4 and the electrode substrate 91, a gap is formed between the annular vibration stopping layer 6 and the diaphragm 40, and the annular vibration stopping layer 6 is used for blocking the diaphragm 40. In actual use, the diaphragm 40 of the diaphragm structure 4 may move to the side close to the electrode substrate 91 or to the side close to the annular vibration stopper layer 6. At this time, in the case where the normal operation of the diaphragm 40 of the diaphragm structure 4 is ensured, and the distance of the diaphragm 40 moving toward the side close to the electrode substrate 91 is substantially identical or completely identical or increased to the distance of the diaphragm 40 moving toward the side close to the electrode layer 2 in the related art, the total movement displacement of the diaphragm 40, that is, the vibration amplitude of the diaphragm 40 is increased, as compared with the related art, thereby improving the sound pressure level of the sound generating unit. Illustratively, after the release of the first and second sacrificial layers 92, 94 is completed, an attractive electrostatic force is applied and the diaphragm 40 is moved to a side closer to the electrode substrate 91, the displacement being denoted as displacement 1. The diaphragm 40 moves toward the annular vibration stopper 6 by applying repulsive electrostatic force, and the displacement is denoted as displacement 2. At this time, the total displacement of the diaphragm 40 is equal to the displacement 1 plus the displacement 2.

In the description of the above embodiments, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A sound generating unit, comprising:

A semiconductor substrate having a cavity;

An electrode layer disposed on the semiconductor substrate; at least one through hole is formed in the electrode layer along the height direction of the electrode layer, and the through hole penetrates through the electrode layer; the through holes are communicated with the cavity and are oppositely arranged;

an annular first support structure disposed on the electrode layer;

The vibrating diaphragm structure is arranged on the annular first supporting structure; a gap is formed between the vibrating diaphragm structure and the electrode layer; the vibrating diaphragm structure comprises a vibrating diaphragm and a cantilever beam positioned at the periphery of the vibrating diaphragm, and the vibrating diaphragm is arranged opposite to the through hole;

The annular second supporting structure is arranged on the vibrating diaphragm structure;

the annular vibration stopping layer is arranged on the annular second supporting structure; and a gap is reserved between the annular vibration stopping layer and the vibrating diaphragm, and the annular vibration stopping layer is used for blocking the vibrating diaphragm.

2. The sound generating unit according to claim 1, wherein a maximum distance between two inner walls of the annular vibration stopper layer, which are relatively distributed, for blocking the diaphragm is smaller than a minimum distance between two side walls of the annular vibration stopper layer, which are relatively distributed; the annular vibration stop layer is non-conductive.

3. The sound generating unit according to claim 1, wherein the through holes include a first through hole and a second through hole communicating in a height direction of the electrode layer; the first through hole is positioned between the cavity and the second through hole;

The width of the first through hole is larger than that of the second through hole; the width direction of the first through hole and the width direction of the second through hole are perpendicular to the height direction of the electrode layer; and/or the depth of the first through hole is larger than the depth of the second through hole; the depth direction of the first through hole and the depth direction of the second through hole are consistent with the height direction of the electrode layer; and/or, along the height direction perpendicular to the electrode layer, one through hole comprises a plurality of second through holes which are distributed at intervals.

4. The sound emitting unit of claim 1, further comprising:

The insulating bulges are arranged on the electrode layer and face the vibrating diaphragm;

Gaps are formed between all the insulating protrusions and the vibrating diaphragm along the height direction of the electrode layer;

the insulation protrusions are distributed at intervals along the height direction perpendicular to the electrode layer, and the through holes and the insulation protrusions are distributed at intervals.

5. The sound emitting unit of claim 4, further comprising:

the first insulating layer is arranged on the electrode layer, and the insulating protrusions are arranged on the first insulating layer; the via hole penetrates through the electrode layer and the first insulating layer at the same time.

6. A method of making a sound unit comprising:

providing a semiconductor substrate and an electrode substrate; the electrode substrate has opposed first and second faces;

A first through hole is formed in the first surface of the electrode substrate along the height direction of the electrode substrate; the depth of the first through hole is smaller than the height of the electrode substrate, and the depth direction of the first through hole is consistent with the height direction of the electrode substrate;

disposing a first face of the electrode substrate on the semiconductor substrate;

A second through hole is formed in the second surface of the electrode substrate along the height direction of the electrode substrate, the first through hole is communicated with the second through hole, and the first through hole and the second through hole corresponding to the first through hole penetrate through the electrode substrate;

Forming a first sacrificial layer on the second surface of the electrode substrate and in the second through hole, and processing the first sacrificial layer to enable the first sacrificial layer to be provided with a first stop groove; the first stopping groove is positioned at the periphery of the second through hole;

Forming a vibrating diaphragm structure in the first sacrificial layer and the first stopping groove, processing the vibrating diaphragm structure to form a vibrating diaphragm and a cantilever beam positioned at the periphery of the vibrating diaphragm, wherein the first stopping groove is positioned at the periphery of the cantilever beam;

forming a second sacrificial layer on the vibrating diaphragm structure, and processing the second sacrificial layer to enable the second sacrificial layer to be provided with a second stop groove; the second stopping groove is positioned at the periphery of the cantilever beam;

forming a vibration stopping layer in the second sacrificial layer and the second stopping groove, and processing the vibration stopping layer to form an annular vibration stopping layer;

Along the direction from the semiconductor substrate to the electrode substrate, a cavity is formed in the semiconductor substrate, and the first through hole is communicated with the cavity and is oppositely arranged;

removing the first sacrificial layer in the first stopping groove so that the vibrating diaphragm and the second through hole are arranged opposite to each other, and a gap is reserved between the vibrating diaphragm structure and the electrode substrate; and removing the second sacrificial layer in the second stopping groove so that a gap is formed between the annular vibration stopping layer and the vibrating diaphragm, wherein the annular vibration stopping layer is used for blocking the vibrating diaphragm.

7. The method of manufacturing a sound generating unit according to claim 6, further comprising, after disposing the first surface of the electrode substrate on the semiconductor substrate:

Forming a plurality of insulating protrusions on a second face of the electrode substrate, the insulating protrusions facing the diaphragm; a plurality of insulating protrusions are distributed at intervals along a height direction perpendicular to the electrode substrate;

after a second through hole is formed in the second surface of the electrode substrate, the first through hole and the second through hole are distributed with the insulating protrusions at intervals;

and after the first sacrificial layer in the first stopping groove is removed, gaps are reserved between all the insulating protrusions and the vibrating diaphragm along the height direction of the electrode substrate.

8. The method of manufacturing a sound generating unit according to claim 7, further comprising, after forming a plurality of insulating protrusions on the second surface of the electrode base:

Forming a first insulating layer on the electrode substrate and the insulating bump;

And forming a second through hole on the electrode substrate and the first insulating layer along the direction from the electrode substrate to the first insulating layer, wherein the first through hole and the second through hole corresponding to the first through hole penetrate through the electrode substrate and the first insulating layer.

9. The method of manufacturing a sound generating unit according to claim 6, wherein the width of the first through hole is larger than the width of the second through hole; the width direction of the first through hole and the width direction of the second through hole are perpendicular to the height direction of the electrode substrate; and/or the number of the groups of groups,

The depth of the first through hole is larger than that of the second through hole; the depth direction of the first through hole and the depth direction of the second through hole are consistent with the height direction of the electrode substrate; and/or the number of the groups of groups,

One of the through holes includes a plurality of second through holes spaced apart in a height direction perpendicular to the electrode substrate.

10. The method of claim 6, wherein a maximum distance between two inner walls of the annular vibration stopper layer for blocking the diaphragm is smaller than a minimum distance between two sidewalls of the annular vibration stopper layer; the annular vibration stop layer is non-conductive.