CN217363307U

CN217363307U - Micro-electromechanical structure, microphone and terminal

Info

Publication number: CN217363307U
Application number: CN202221029013.8U
Authority: CN
Inventors: 刘青; 荣根兰
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2022-09-02
Anticipated expiration: 2032-04-29

Abstract

The present disclosure provides a micro-electromechanical structure, a microphone and a terminal, the micro-electromechanical structure comprising: a first diaphragm; a first back plate opposite to a surface of the first diaphragm; the first diaphragm comprises a movable area, and the movable area comprises a central area and an edge area surrounding the central area; the plurality of through holes comprise a plurality of first through holes and a plurality of second through holes, the first through holes correspond to the central area, the second through holes correspond to the edge area, and the size of the second through holes is larger than that of the first through holes. According to the micro-electromechanical structure, the second through hole with the larger size is formed in the edge region of the back plate, the damping of airflow flowing through the back plate is reduced so as to reduce noise, and under the condition that the areas of the vibrating diaphragm and the back plate are limited, the additional capacitor is added through the bulge parts of the corresponding through holes formed in the vibrating diaphragm, the fact that the capacitor between the back plate and the vibrating diaphragm can reach a preset value is guaranteed, and therefore the signal-to-noise ratio of the micro-electromechanical structure is improved.

Description

Micro-electromechanical structure, microphone and terminal

Technical Field

The present disclosure relates to the field of semiconductor device manufacturing, and more particularly to microelectromechanical structures, microphones, and terminals.

Background

Devices manufactured based on Micro Electro Mechanical Systems (MEMS) are called MEMS devices, and the MEMS devices mainly include a conductive diaphragm and a back plate with a gap therebetween. The change of atmospheric pressure can lead to the vibrating diaphragm to warp, and the capacitance value between vibrating diaphragm and the backplate changes thereupon to convert the signal of telecommunication output into.

The MEMS microphone is a microphone manufactured by a surface processing or bulk silicon processing process compatible with integrated circuit manufacturing, and can be made very small due to the use of a continuously miniaturized Complementary Metal Oxide Semiconductor (CMOS) process technology, so that it can be widely applied to portable devices such as mobile phones, notebook computers, tablet computers, and cameras. Nowadays, the performance of the MEMS microphone is more and more demanding, wherein SIGNAL-to-NOISE RATIO (SNR) and sensitivity are related to capacitance value of the capacitor, which are important indicators of the performance of the MEMS microphone.

Therefore, it is desirable to provide an improved microphone and a micro-electromechanical structure thereof to ensure that a capacitance between a back plate and a diaphragm can reach a preset value, thereby achieving the purpose of improving product performance.

SUMMERY OF THE UTILITY MODEL

In view of this, the present disclosure provides an improved mems structure, a microphone and a terminal, in which a through hole with a larger size is formed on a back plate, and a protrusion corresponding to the through hole is formed on a diaphragm, so as to improve the signal-to-noise ratio of the mems structure.

According to a first aspect of embodiments of the present disclosure, there is provided a microelectromechanical structure comprising:

a first diaphragm;

a first back plate opposite to a surface of the first diaphragm; and

a plurality of through holes penetrating the first back plate,

the first diaphragm includes a plurality of first bosses corresponding to at least some of the plurality of through holes,

the first diaphragm comprises a movable area, and the movable area comprises a central area and an edge area surrounding the central area;

the through holes comprise a plurality of first through holes and a plurality of second through holes, the first through holes correspond to the central area, the second through holes correspond to the edge area, and the size of the second through holes is larger than that of the first through holes.

Optionally, the distance from the center of the central region to the edge of the central region is R1, the distance from the center of the active region to the edge of the active region is R2, the ratio of R1 to R2 is less than or equal to 3:4,

the central region coincides with the center of the active region.

Optionally, at least one section of the first diaphragm is corrugated along a thickness direction of the first diaphragm, and the sections of the plurality of first protrusions are peaks or valleys of the corrugations.

Optionally, a junction between the top surface and the side surface of at least one of the first protruding portions is arc-shaped.

Optionally, a plurality of anti-sticking portions are included, and are located on one side of the first back plate facing the first diaphragm and staggered from the plurality of first protruding portions.

Optionally, a second supporting portion located between the first diaphragm and the first back plate is included,

the second supporting part is in contact with the first back plate and is in contact with the non-convex part of the first diaphragm,

along the thickness direction of the first diaphragm, the vertical distance from the non-bulge part of the first diaphragm to the surface of the first bulge part is smaller than the thickness of the second support part.

Optionally, a vertical distance from a non-convex portion of the first diaphragm to a surface of the first convex portion is h1, a thickness of the second supporting portion is h2, and h1 is less than or equal to 0.5h 2.

Optionally, at least some of the plurality of through holes have a size larger than a size of the corresponding first protrusion.

Optionally, the plurality of first projections are located only in the central region.

Optionally, the first back plate comprises a first insulating layer and a first conductive layer,

the first diaphragm and the first conducting layer are respectively positioned at two opposite sides of the first insulating layer,

the size of the first conductive layer is smaller than that of the first insulating layer, and an orthographic projection of the first conductive layer on the first diaphragm falls within the central region.

Optionally, the sizes of the second through holes gradually increase along the direction from the center to the edge of the first back plate.

Optionally, a second back plate is included, and the second back plate and the first back plate are respectively located on two opposite sides of the first diaphragm.

Optionally, a plurality of third through holes are included, penetrating the second back plate,

the first protruding parts and the third through holes are staggered mutually.

Optionally, a second diaphragm is included, and the second diaphragm and the first diaphragm are respectively located on two opposite sides of the first backplate.

Optionally, the second diaphragm includes a plurality of second protrusions corresponding to at least some of the plurality of through holes.

Optionally, at least one section of the second diaphragm is corrugated along the thickness direction of the second diaphragm, and the sections of the second protruding portions are peaks or valleys of the corrugations.

Optionally, a third supporting portion located between the second diaphragm and the first back plate is included,

the third supporting part is in contact with the first back plate and is in contact with the non-convex part of the second diaphragm,

along the thickness direction of the second diaphragm, the distance from the non-convex part of the second diaphragm to the surface of the second convex part is less than the thickness of the third supporting part.

Optionally, at least some of the plurality of through holes have a size larger than a size of the corresponding second protrusion.

Optionally, a junction between the top surface and the side surface of at least one of the second protrusions is arc-shaped.

According to a second aspect of embodiments of the present disclosure, there is provided a microphone comprising a microelectromechanical structure as described above.

According to a third aspect of embodiments of the present disclosure, there is provided a terminal comprising the microphone as described above.

According to the micro-electromechanical structure provided by the embodiment of the disclosure, the second through hole with a larger size is arranged on the first back plate, so that the damping of airflow flowing through the through hole of the first back plate is reduced, and the noise of the micro-electromechanical structure is further reduced; although the increase of the size of the through hole can correspondingly reduce the opposite area of the first back plate and the first diaphragm moving area, so that the capacitance is reduced, and the sensitivity of the micro-electromechanical structure is reduced, the first through hole with smaller size corresponds to the central area of the first diaphragm moving area, the second through hole with larger size corresponds to the edge area of the first diaphragm moving area, and the deformation capacity of the edge area of the first diaphragm moving area is smaller than that of the central area, so that the influence of the second through hole with larger size on the whole sensitivity of the micro-electromechanical structure is smaller when the first back plate corresponding to the edge area of the first diaphragm moving area is provided with the second through hole with larger size; meanwhile, the additional capacitance increased due to the first vibrating diaphragm bulge can compensate the capacitance reduced due to the reduced dead area, under the condition that the areas of the first vibrating diaphragm and the first back plate are limited, compared with the first vibrating diaphragm without the bulge, the vertical distance from the surface of the first vibrating diaphragm with the bulge to the edge of the through hole of the first back plate is shortened, the additional capacitance generated by the edge effect of the capacitor is increased, the total capacitance between the first back plate and the first vibrating diaphragm can reach a preset value, the sensitivity of the micro-electromechanical structure further reaches a preset requirement, and the signal-to-noise ratio of the micro-electromechanical structure is improved by the arrangement of the second through hole and the first vibrating diaphragm bulge.

Because the top surface of first vibrating diaphragm bellying is the arc with the junction of side, thereby further released the stress of first vibrating diaphragm and promoted micro electromechanical structure's sensitivity.

Through setting up a plurality of antiseized portions in first backplate towards one side of first vibrating diaphragm and stagger with the bellying to can enough make antiseized portion not touch the bellying of first vibrating diaphragm, effectively prevent the adhesion of first backplate and first vibrating diaphragm again, promote micro electromechanical structure's mechanical reliability.

In the vertical direction, in the state that the first vibrating diaphragm and the first back plate are relatively static, the distance from the surface of the non-convex part of the first vibrating diaphragm to the convex part of the first vibrating diaphragm is smaller than the distance from the surface of the non-convex part of the first vibrating diaphragm to the lower surface of the first back plate, so that when the vibration amplitude of the first vibrating diaphragm is small, the convex part of the first vibrating diaphragm cannot stretch into the through hole of the first back plate, and the damping of airflow flowing through the back plate is reduced so as to reduce noise. Furthermore, because the size of the first diaphragm boss is smaller than that of the corresponding first backboard through hole, when the vibration amplitude of the first diaphragm is large, even if the first diaphragm boss extends into the corresponding through hole, the first diaphragm boss is not easy to touch the side wall of the through hole, so that the risk of damage of the first diaphragm is reduced, and the mechanical reliability of the micro-electromechanical structure is improved.

Furthermore, the plurality of first protruding portions are only corresponding to the central area, and the orthographic projection of the first conducting layer on the first vibrating diaphragm is located in the central area, and because the deformation capability of the first vibrating diaphragm is strong in the central area, the variation range of the capacitance formed by the central area of the first vibrating diaphragm and the first conducting layer is large; and at the edge region, the deformation energy of the first diaphragm is weaker, and for a capacitor formed by the edge region of the first diaphragm and the first conducting layer, the variation range is smaller, and the contribution to the whole sound airflow response is small. Therefore, the first conductive layer and the first protrusion are positioned to correspond to the central region of the first diaphragm, and the first conductive layer is not formed at the edge region. In the first backboard, the first through hole with smaller size corresponds to the first conducting layer, and the second through hole with larger size does not need to penetrate through the first conducting layer any more and is only positioned in the first insulating layer at the edge, so that the acoustic resistance is further reduced, the effect of increasing the edge capacitance is obvious, and the signal-to-noise ratio is further improved.

Therefore, the micro-electromechanical structure and the microphone provided by the disclosure can greatly improve the performance of products.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description only relate to some embodiments of the present disclosure and do not limit the present disclosure.

Fig. 1 is a schematic perspective view of a micro-electromechanical structure according to a first embodiment of the disclosure.

Fig. 2 is a schematic perspective view of the first backplane hidden in fig. 1.

Fig. 3 is a schematic perspective view with a cross section in fig. 1.

Fig. 4 is a schematic cross-sectional view taken along line AA in fig. 1.

Fig. 5 is an enlarged schematic diagram of the dotted frame in fig. 4.

Fig. 6 is a schematic top view of the first backplate in fig. 1.

Fig. 7 to 9 are schematic diagrams of the capacitor fringe effect.

Fig. 10 is a schematic view of a microelectromechanical structure according to a second embodiment of the present disclosure.

Fig. 11 is a schematic view of a micro-electromechanical structure according to a third embodiment of the disclosure.

Fig. 12 is a schematic view of a microelectromechanical structure according to a fourth embodiment of the present disclosure.

Fig. 13 is a schematic view of a micro-electromechanical structure according to a fifth embodiment of the disclosure.

Fig. 14 is a schematic structural diagram of a microphone according to an embodiment of the present disclosure.

Detailed Description

The present disclosure will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. In addition, certain well known components may not be shown. For simplicity, the semiconductor structure obtained after several steps can be described in one figure.

It will be understood that when a layer or region is referred to as being "on" or "over" another layer or region in describing the structure of the device, it can be directly on the other layer or region or intervening layers or regions may also be present. And, if the device is turned over, that layer, region, or regions would be "under" or "beneath" another layer, region, or regions.

Numerous specific details of the present disclosure, such as structure, materials, dimensions, processing techniques and techniques of the devices, are set forth in the following description in order to provide a more thorough understanding of the present disclosure. However, as will be understood by those skilled in the art, the present disclosure may be practiced without these specific details.

The present disclosure may be presented in various forms, some examples of which are described below.

As shown in fig. 1 to 6, a micro-electromechanical structure according to a first embodiment of the present disclosure includes: the diaphragm comprises a substrate 101, a first supporting part 111, a second supporting part 112, a first diaphragm 120, a first back plate 130 and a plurality of through holes penetrating through the first back plate 130. The substrate 101 has a cavity 10. The first support part 111 is located at an edge on the substrate 101. The first diaphragm 120 is positioned on the first support part 111 and covers the cavity 10. The second supporting portion 112 is located on the first diaphragm 120, and the position corresponds to the first supporting portion 111. The first back plate 130 is located on the second supporting portion 112, and has a gap with the first diaphragm 120.

In this embodiment, the first supporting portion 111 is a portion left on the substrate 101 after the sacrificial layer is released, the first supporting portion 111 is located on the peripheral edge of the substrate 110, and the first diaphragm 120 located above the first supporting portion 111 is supported on the substrate 101 in a manner that the peripheral edge is fully supported. The second supporting portion 112 is a portion left on the first diaphragm 120 after the sacrificial layer is released, the second supporting portion 112 is located on the peripheral edge of the first diaphragm 120, and the first back plate 130 located above the second supporting portion 112 is supported and fixed by a full-solid-supported manner of the peripheral edge. However, the embodiments of the present disclosure are not limited thereto, and a person skilled in the art may perform other arrangements on the fixing manner among the substrate 101, the first diaphragm 120, and the first backplate 130 as needed.

In some embodiments, the substrate 101 is a silicon substrate, and the chamber 10 is located in the middle of the substrate 101 and communicates with two opposite surfaces of the substrate 101. Of course, the position, shape, etc. of the cavity 10 can be set by those skilled in the art according to the needs, and is not limited herein. The material of the first supporting portion 111 and the second supporting portion 112 is an insulating material, including but not limited to silicon oxide.

Further, the first back plate 130 includes a first insulating layer 131 and a first conductive layer 132 stacked on the second support portion 112 along the thickness direction of the substrate 101. The material of the first insulating layer 131 includes, but is not limited to, silicon nitride, and the material of the first conductive layer 132 includes, but is not limited to, polysilicon. The size of the first conductive layer 132 is smaller than that of the first insulating layer 131, and the position of the first conductive layer 132 corresponds to the vibration region of the diaphragm 120. However, the embodiments of the present disclosure are not limited thereto, and those skilled in the art may make other arrangements on the material and structure of the first back plate 130 as needed, for example, the first back plate 130 is arranged in a structure of two insulating layers sandwiching a conductive layer, or the first back plate 130 is formed by only one conductive layer, and so on.

The first diaphragm 120 includes a movable region, and the movable region of the first diaphragm 120 includes a central region S1 and an edge region S2 surrounding the central region S1. In some specific embodiments, the center of the central region S1 is a distance R1 from the center of the central region S1, the center of the active region is a distance R2 from the edge of the active region, and the ratio of R1 to R2 is equal to or less than 3:4, wherein the central region S1 coincides with the center of the active region. In some preferred embodiments, the ratio of R1 to R2 is equal to 3: 4.

In the present embodiment, the plurality of through holes include a plurality of first through holes 11 and a plurality of second through holes 12, wherein the plurality of first through holes 11 are located at the middle corresponding to the central area S1 of the back plate 130, the plurality of second through holes 12 surround the plurality of first through holes 11 corresponding to the edge areas S2, and each of the second through holes 12 has a size larger than that of the first through hole 11. The first conductive layer 132 and the first insulating layer 131 pass through the first through holes 11 and the second through holes 12, the first through holes 11 and the second through holes 12 are circular holes, and the first through holes 11 and the second through holes 12 have diameters, which is obvious for those skilled in the art to set the shapes of the through holes in other ways as needed.

In some specific embodiments, the size of the second through holes 12 gradually increases along the direction from the center to the edge of the first back plate 130, as shown in fig. 6. Since the deformation capability of the first diaphragm 120 is gradually reduced along the direction from the center to the edge of the first diaphragm 120, following this rule, the size of the through hole on the first back plate 130 closer to the center is smaller, and the size of the through hole closer to the edge is larger, so as to reduce damping by using the second through hole 12 with gradually increased size without affecting the sensitivity of the micro-electromechanical structure as much as possible. However, the present embodiment is not limited thereto, and those skilled in the art may make other arrangements according to the size change of the second through hole 12.

Further, the material of the first diaphragm 120 includes, but is not limited to, polysilicon. The first diaphragm 120 includes a non-convex portion 120b and a plurality of first convex portions 120a, and the plurality of first convex portions 120a correspond to at least some of the plurality of first through holes 11 and/or the plurality of second through holes 12.

In this embodiment, the second support portion 112 corresponds to a fixed region of the periphery of the movable region of the first diaphragm 120, and is in contact with the non-convex portion 120b of the first diaphragm 120. In the thickness direction of the first diaphragm 120, the vertical distance from the non-convex portion 120b of the first diaphragm 120 to the surface of the first convex portion 120a is h1, the thickness of the second support portion 112 is h2, and h1< h 2. It can also be understood that: in the vertical direction, in a state where the first diaphragm 120 and the first backplate 130 are relatively stationary, a vertical distance reaching the first convex portion 120a is shorter than a distance reaching the lower surface of the first backplate 130, with the surface of the non-convex portion 120b of the first diaphragm 120 as a starting point. When the vibration amplitude of the first diaphragm 120 is small, the first protrusion 120a does not extend into the through hole of the first backplate 130, so that the damping of the airflow flowing through the first backplate 130 is reduced to reduce noise; when the vibration amplitude of the first diaphragm 120 is large, even if the first protrusion 120a extends into the corresponding through hole, the first protrusion 120a does not easily touch the sidewall of the through hole, so that the risk of damage to the first diaphragm 120 is reduced, and the mechanical reliability of the micro-electromechanical structure is improved. In some specific embodiments, h1 ≦ 0.5h 2.

In the present embodiment, each first protrusion 120a corresponds to a through hole (including the first through hole 11 and the second through hole 12) on the back plate 130 one by one, and the shape of the first protrusion 120a is similar to that of the corresponding through hole, for example, the through hole is a circular hole, and the first protrusion 120a is a circular protrusion. In some other embodiments, the first protrusion 120a may correspond to only the first through hole 11, or only the second through hole 12. As shown in fig. 5, the conductive layer 132 of the first backplate 130 not only forms a capacitance C1 opposite to the first diaphragm 120 on the bottom surface, but also forms an additional capacitance C2 in parallel with the capacitance C1 due to the edge effect of the capacitor, and in order to further illustrate the edge effect of the capacitor, the following will be described in detail with reference to fig. 7 to 9.

As shown in fig. 7 and 8, the first conductive layer 132 of the first back plate 130 and the first diaphragm 120 may be regarded as a parallel plate capacitor, in the middle of which the electric field lines are uniformly distributed, but the distribution of the electric field lines is not uniform at the edges, causing an edge effect of the capacitor, which is equivalent to connecting a C2 in parallel beside the capacitance C1. As shown in fig. 9, when a convex portion is provided in the first diaphragm 120, the vertical distance of the convex surface where the convex portion is provided to the edge of the through-hole of the first backplate 130 is shortened relative to the first diaphragm 120 where no convex portion is provided, and therefore the additional capacitance C2 due to the capacitor edge effect increases. Therefore, under the condition that the second through hole 12 with a larger size is arranged, the capacitance value between the first back plate 130 and the first diaphragm 120 can reach a preset value. The cross section of the first diaphragm 120 is corrugated along the thickness direction of the first diaphragm 120, and the cross sections of the first protrusions 120a are peaks of the corrugations. A dimension d2 of at least some of the plurality of first through holes 11 and/or the plurality of second through holes 12 is greater than a dimension d1 of the corresponding first protrusion 120 a. In some preferred embodiments, the connection between the top surface and the side surface of the first protrusion 120a is arc-shaped, so as to further release the stress of the first diaphragm 120 and thus improve the sensitivity of the mems.

Further, the micro-electromechanical structure of the embodiment further includes a plurality of anti-sticking portions 140 located on one side of the first backplate 130 facing the first diaphragm 120, so that the anti-sticking portions 140 do not touch the first protrusion portion 120a, adhesion between the first backplate 130 and the first diaphragm 120 is effectively prevented, and mechanical reliability of the micro-electromechanical structure is improved.

The mems structure of this embodiment further includes a plurality of bonding pads (not shown) on the first backplate 130 for forming electrical connections with the first backplate 130 and the first diaphragm 120, respectively.

As shown in fig. 10, the micro-electromechanical structure of the second embodiment of the disclosure is similar to that of the first embodiment, and can be described with reference to fig. 1 to 9, and the same parts are not repeated. The difference from the first embodiment is that the plurality of first protrusions 120a in this embodiment are located only in the central region S1, and the orthographic projection of the first conductive layer 132 on the first diaphragm 120 falls within the central region S1.

Since the deformability of the first diaphragm 120 gradually increases along the direction from the edge of the first diaphragm 120 to the center, and the deformability of the first diaphragm 120 is strong in the central area S1, the variation range of the capacitance formed by the central area S1 of the first diaphragm 120 and the first conductive layer 132 is large, and the capacitance formed by the central area S1 of the first diaphragm 120 and the first conductive layer 132 can be regarded as the effective capacitance; in the edge region S2, the deformation energy of the first diaphragm 120 is relatively weak, and the capacitance formed by the edge region S2 of the first diaphragm 120 and the first conductive layer 132 has a relatively small variation range, and does not contribute much to the overall sound airflow response. Therefore, in the present embodiment, the positions of the first conductive layer 132 and the first protrusion 120a correspond to the central region S1 of the first diaphragm 120, and the first conductive layer 132 and the first protrusion 120a are not formed at the edge region S2. In the first back plate 130, the first through hole 11 with smaller size corresponds to the first conductive layer 132, and the second through hole 12 with larger size does not need to penetrate the first conductive layer 132 any more, and the second through hole 12 is only located in the first insulating layer 131 at the edge. Compared with the first embodiment, the micro-electromechanical structure of the embodiment further reduces the acoustic resistance, has an obvious effect of increasing the fringe capacitance, and further improves the signal-to-noise ratio.

As shown in fig. 11, the micro-electromechanical structure of the third embodiment of the present disclosure is similar to that of the first embodiment, and can refer to the descriptions of fig. 1 to 9, and the same parts are not repeated. The difference from the first embodiment is that the positions of the first back plate 130 and the first diaphragm 120 in this embodiment are reversed.

Fig. 12 is a schematic view of a micro-electromechanical structure according to a fourth embodiment of the disclosure.

As shown in fig. 12, the micro-electromechanical structure of the fourth embodiment of the disclosure is similar to the first embodiment, and can refer to the descriptions of fig. 1 to 9, and the same parts are not described again. The difference from the first embodiment is that the structure of the microcomputer in this embodiment further includes a second back plate 150 and a third supporting portion 113. The first support part 111, the second back plate 150, the second support part 112, the first diaphragm 120, the third support part 113, and the first back plate 130 are sequentially stacked on the substrate 101 in a thickness direction of the substrate 101. The third through holes 13 penetrate through the second backplate 150, and the first protrusions 120a and the third through holes 13 are staggered. In the present embodiment, the material of the third supporting portion 113 includes, but is not limited to, silicon oxide, and the material and structure of the second back plate 150 are similar to those of the first back plate 130, including the second insulating layer 152 and the second conductive layer 151 connected thereto. Of course, other arrangements of the material and structure of the second back plate 150 can be made by those skilled in the art according to the needs. In this embodiment, the third support portion 113 is in contact with the non-convex portion of the second diaphragm 160, and the distance from the non-convex portion of the second diaphragm 120 to the surface of the second convex portion 160a in the thickness direction of the second diaphragm 160 is smaller than the thickness of the third support portion 113.

As shown in fig. 13, the micro-electromechanical structure of the fifth embodiment of the present disclosure is similar to that of the first embodiment, and can refer to the descriptions of fig. 1 to 9, and the same parts are not repeated. The difference from the first embodiment is that the micro-electromechanical structure in this embodiment further includes a second diaphragm 160 and a third supporting portion 113, and the first back plate 130 further includes an insulating layer 133 and an insulating layer 131 respectively located on two opposite sides of the conductive layer 132. The third supporting portion 113 is a portion left on the first backplate 130 after the sacrificial layer is released, the third supporting portion 113 is located on the peripheral edge of the first backplate 130, and the second diaphragm 160 located above the third supporting portion 113 is supported and fixed by adopting a manner of completely supporting the peripheral edge. The material of the third support portion 113 includes, but is not limited to, silicon oxide.

The second diaphragm 160 includes a plurality of second bosses 160a corresponding to at least some of the plurality of first through holes 11 and/or the plurality of second through holes 12. The second diaphragm 160 has a corrugated shape in cross section along the thickness direction of the second diaphragm 160, and the plurality of second protrusions 160a have a trough in cross section. At least some of the plurality of first through holes 11 and/or the plurality of second through holes 12 have a size larger than that of the corresponding second protrusion 160 a. Preferably, the junction of the top surface and the side surface of the second protrusion 160a is arc-shaped. The material of the second diaphragm 160 includes, but is not limited to, polysilicon.

Fig. 14 shows a schematic structural diagram of a MEMS microphone according to an embodiment of the present invention.

As shown in fig. 14, the MEMS microphone includes: micro-electromechanical structure 100, chip structure 200, substrate 300, shell 400. The substrate 300 and the housing 400 serve as a package structure of the device. The micro-electromechanical structure 100 according to the embodiment of the present invention can be selected from the four embodiments listed above, the chip structure 200 is, for example, an ASIC chip, and the substrate 300 is, for example, a lead frame or a PCB circuit board.

In the embodiment, the pad of the mems structure 100 is electrically connected to the chip structure 200, the substrate 300 and the housing 400 of the package structure are used to form an accommodating cavity of the package structure, and the mems structure 100 and the chip structure 200 are located in the accommodating cavity.

The present disclosure also provides a terminal including the microphone as described above.

According to the micro-electromechanical structure provided by the embodiment of the disclosure, the second through hole with a larger size is arranged on the first backboard, so that the damping of air flow flowing through the through hole of the first backboard is reduced, and the noise of the micro-electromechanical structure is further reduced; although the increase of the size of the through hole can correspondingly reduce the opposite area of the first back plate and the first diaphragm moving area, so that the capacitance is reduced, and the sensitivity of the micro-electromechanical structure is reduced, the first through hole with smaller size corresponds to the central area of the first diaphragm moving area, the second through hole with larger size corresponds to the edge area of the first diaphragm moving area, and the deformation capacity of the edge area of the first diaphragm moving area is smaller than that of the central area, so that the influence of the second through hole with larger size on the whole sensitivity of the micro-electromechanical structure is smaller when the first back plate corresponding to the edge area of the first diaphragm moving area is provided with the second through hole with larger size; meanwhile, the additional capacitance increased due to the first vibrating diaphragm bulge can compensate the capacitance reduced due to the reduced dead area, under the condition that the areas of the first vibrating diaphragm and the first back plate are limited, compared with the first vibrating diaphragm without the bulge, the vertical distance from the surface of the first vibrating diaphragm with the bulge to the edge of the through hole of the first back plate is shortened, the additional capacitance generated by the edge effect of the capacitor is increased, the total capacitance between the first back plate and the first vibrating diaphragm can reach a preset value, the sensitivity of the micro-electromechanical structure further reaches a preset requirement, and the signal-to-noise ratio of the micro-electromechanical structure is improved by the arrangement of the second through hole and the first vibrating diaphragm bulge.

Through setting up a plurality of antiseized portions in first backplate towards one side of vibrating diaphragm and stagger with the bellying to can enough make antiseized portion not touch the bellying of first vibrating diaphragm, effectively prevent the adhesion of first backplate and first vibrating diaphragm again, promote micro electromechanical structure's mechanical reliability.

Furthermore, the plurality of first bulges are only corresponding to the central area, and the orthographic projection of the first conducting layer on the first vibrating diaphragm is in the central area, and the deformation capability of the first vibrating diaphragm is strong in the central area, so that the change range of the capacitance formed by the central area of the first vibrating diaphragm and the first conducting layer is large; and at the edge region, the deformation energy of the first diaphragm is weaker, and for a capacitor formed by the edge region of the first diaphragm and the first conducting layer, the variation range is smaller, and the contribution to the whole sound airflow response is small. Therefore, the first conductive layer and the first protrusion are positioned to correspond to the central region of the first diaphragm, and the first conductive layer is not formed at the edge region. In the first back plate, the first through hole with smaller size corresponds to the first conducting layer, and the second through hole with larger size does not need to penetrate through the first conducting layer any more and is only positioned in the first insulating layer at the edge, so that the acoustic resistance is further reduced, the effect of increasing the edge capacitance is obvious, and the signal-to-noise ratio is further improved.

In the above description, the technical details of patterning, etching, and the like of each layer are not described in detail. It will be appreciated by those skilled in the art that layers, regions, etc. of the desired shape may be formed by various technical means. In addition, in order to form the same structure, the person skilled in the art can also design a method which is not exactly the same as the method described above. In addition, although the embodiments are described separately above, this does not mean that the measures in the embodiments cannot be used in advantageous combination.

The embodiments of the present disclosure have been described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be devised by those skilled in the art without departing from the scope of the disclosure, and these alternatives and modifications are intended to fall within the scope of the disclosure.

Claims

1. A microelectromechanical structure, comprising:

a first diaphragm;

a first back plate opposite to a surface of the first diaphragm; and

a plurality of through holes penetrating through the first back plate,

2. The microelectromechanical structure of claim 1, characterized in that the center of the central region is a distance R1 from the edge of the central region, the center of the active region is a distance R2 from the edge of the active region, the ratio of R1 to R2 is equal to or less than 3:4,

the central region coincides with the center of the active region.

3. The mems structure of claim 1, wherein at least a cross-section of the first diaphragm is corrugated along a thickness direction of the first diaphragm, and a cross-section of the first plurality of protrusions is a peak or a valley of the corrugation.

4. The microelectromechanical structure of claim 1, characterized in that the junction of the top surface and the side surface of at least one of the first projections is curved.

5. The mems structure of claim 1, comprising a plurality of anti-sticking portions on a side of the first backplate facing the first diaphragm, offset from the plurality of first raised portions.

6. The microelectromechanical structure of any of claims 1-5, characterized by a second support portion located between the first diaphragm and the first back plate,

7. The micro-electromechanical structure of claim 6, wherein a vertical distance from a non-convex portion of the first diaphragm to a surface of the first convex portion is h1, a thickness of the second supporting portion is h2, and h1 is less than or equal to 0.5h 2.

8. The microelectromechanical structure of claim 6, characterized in that at least some of the plurality of through-holes have a size larger than a size of the corresponding first protrusions.

9. The microelectromechanical structure of any of claims 1-5, characterized in that the plurality of first raised portions are located only in the central region.

10. The microelectromechanical structure of claim 9, characterized in that the first back plate comprises a first insulating layer and a first conductive layer,

11. The microelectromechanical structure of any of claims 1-5, characterized in that the size of the second plurality of through holes increases gradually in a direction from the center to the edge of the first back plate.

12. The microelectromechanical structure of any of claims 1-5, comprising a second back plate on opposite sides of the first diaphragm from the first back plate.

13. The microelectromechanical structure of claim 12, comprising a third plurality of vias extending through the second back plate,

the first protruding parts and the third through holes are staggered mutually.

14. The microelectromechanical structure of any of claims 1-5, comprising a second diaphragm positioned on opposite sides of the first back-plate from the first diaphragm.

15. The microelectromechanical structure of claim 14, characterized in that the second diaphragm includes a plurality of second protrusions corresponding to at least some of the plurality of through-holes.

16. The mems structure of claim 15, wherein at least a cross section of the second diaphragm is corrugated along a thickness direction of the second diaphragm, and a cross section of the second protrusions is a peak or a trough of the corrugation.

17. The micro-electromechanical structure of claim 14, comprising a third support portion between the second diaphragm and the first back plate,

and along the thickness direction of the second diaphragm, the distance from the non-bulge part of the second diaphragm to the surface of the second bulge part is less than the thickness of the third support part.

18. The microelectromechanical structure of claim 15, characterized in that at least some of the plurality of through-holes have a size larger than a size of the corresponding second protrusions.

19. The microelectromechanical structure of claim 15, characterized in that the junction of the top surface and the side surface of at least one of the second projections is curved.

20. A microphone comprising a microelectromechanical structure of any of claims 1-19.

21. A terminal, characterized in that it comprises a microphone according to claim 20.