CN217363307U - Microelectromechanical structures, microphones and terminals - Google Patents

Abstract

The present disclosure provides a micro-electromechanical structure, a microphone and a terminal. The micro-electromechanical structure includes: a first diaphragm; a first back plate opposite to the surface of the first diaphragm; a plurality of through holes penetrating the first back plate, The first diaphragm includes a plurality of first protrusions, corresponding to at least part of the plurality of through holes, the first diaphragm includes an active area, and the active area includes a central area and an edge area surrounding the central area; the plurality of through holes include 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. The micro-electromechanical structure reduces the damping of the airflow flowing through the back plate to reduce noise by arranging a second through hole with a larger size in the edge area of the back plate. Protruding parts corresponding to the through holes are arranged on the vibrating membrane, and additional capacitance is added to ensure that the capacitance between the back plate and the vibrating membrane can reach a preset value, thereby improving the signal-to-noise ratio of the micro-electromechanical structure.

Description

Microelectromechanical structures, microphones and terminals

technical field

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

Background technique

A device manufactured based on a Micro Electro Mechanical Systems (MEMS) is called a MEMS device. The MEMS device mainly includes a conductive diaphragm and a backplate, and a gap is provided between the diaphragm and the backplate. The change of air pressure will cause the diaphragm to deform, and the capacitance value between the diaphragm and the back plate will change accordingly, which will be converted into electrical signal output.

MEMS microphones are microphones manufactured by surface processing or bulk silicon processing processes that are compatible with integrated circuit manufacturing. Due to the continuous shrinking of complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) process technology, MEMS microphones can be made very small. It can be widely used in portable devices such as mobile phones, notebook computers, tablet computers and cameras. Nowadays, the performance requirements for MEMS microphones are getting higher and higher. Among them, the signal-to-noise ratio (SIGNAL-NOISE RATIO, SNR) is related to the sensitivity and the capacitance value of the capacitor, which are important indicators of the performance of the MEMS microphone.

Therefore, the present disclosure wishes to provide an improved microphone and its MEMS structure to ensure that the capacitance between the back plate and the diaphragm can reach a preset value, thereby achieving the purpose of improving product performance.

Utility model content

In view of this, the present disclosure provides an improved micro-electromechanical structure, a microphone and a terminal. By arranging through holes with larger sizes on the back plate and arranging protrusions corresponding to the through holes on the diaphragm, the improved performance is improved. The MEMS structure has a signal-to-noise ratio.

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

the first diaphragm;

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

a plurality of through holes penetrating the first backplane,

The first diaphragm includes a plurality of first protrusions corresponding to at least part of the plurality of through holes,

The first diaphragm includes an active area, and the active area includes a central area and an edge area surrounding the central area;

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

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

The center area coincides with the center of the active area.

Optionally, along the thickness direction of the first diaphragm, at least one section of the first diaphragm is corrugated, and the sections of the plurality of first protrusions are crests or troughs of the corrugation.

Optionally, the connection between the top surface and the side surface of at least one of the first protruding parts is arc-shaped.

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

Optionally, comprising a second support portion located between the first diaphragm and the first back plate,

the second support 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-convex portion of the first diaphragm to the surface of the first convex portion is smaller than the thickness of the second support portion.

Optionally, the vertical distance from the non-convex portion of the first diaphragm to the surface of the first convex portion is h1, the thickness of the second support portion is h2, and h1≤0.5h2.

Optionally, the size of at least part of the plurality of through holes is larger than the size of the corresponding first protrusion.

Optionally, the plurality of first protrusions are located only in the central area.

Optionally, the first backplane includes a first insulating layer and a first conductive layer,

The first diaphragm and the first conductive layer are respectively located on opposite sides of the first insulating layer,

The size of the first conductive layer is smaller than that of the first insulating layer, and the orthographic projection of the first conductive layer on the first diaphragm falls in the central area.

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

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

Optionally, including a plurality of third through holes, penetrating the second backplane,

The plurality of first protrusions and the plurality of third through holes are staggered from each other.

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

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

Optionally, along the thickness direction of the second diaphragm, at least one cross section of the second diaphragm is corrugated, and the cross sections of the plurality of second protrusions are crests or troughs of the corrugation.

Optionally, comprising a third support portion located between the second diaphragm and the first back plate,

the third support 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 portion of the second diaphragm to the surface of the second convex portion is smaller than the thickness of the third support portion.

Optionally, the size of at least part of the plurality of through holes is larger than the size of the corresponding second protrusion.

Optionally, the connection 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 the embodiments of the present disclosure, there is provided a microphone including the micro-electromechanical structure as described above.

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

According to the microelectromechanical structure provided by the embodiments of the present disclosure, by arranging the second through hole with a larger size on the first backplane, the damping of the airflow flowing through the through hole of the first backplane is reduced, thereby reducing the MEMS structure. Although increasing the size of the through hole will correspondingly reduce the facing area between the first backplate and the active area of the first diaphragm, resulting in a reduction in capacitance and a reduction in the sensitivity of the MEMS structure, the smaller size of the first The through hole corresponds to the central area of the active area of the first diaphragm, the second through hole with a larger size corresponds to the edge area of the active area of the first diaphragm, and the deformation ability of the edge area of the active area of the first diaphragm is compared to The center area is small, so setting a large-sized second through hole on the first back plate corresponding to the edge area of the first diaphragm active area has little effect on the overall sensitivity of the MEMS structure; at the same time, due to the convexity of the first diaphragm The additional capacitance increased by the part can make up for the reduced capacitance due to the reduced facing area. In the case where the area of the first diaphragm and the first back plate is limited, compared with the first diaphragm without the convex part, The vertical distance from the surface of the first diaphragm with the raised portion to the edge of the through hole of the first backplane is shortened, so the additional capacitance caused by the capacitor edge effect increases, thus ensuring the connection between the first backplane and the first diaphragm. The total capacitance value between the two can reach the preset value, so that the sensitivity of the MEMS structure can meet the preset requirements. Therefore, the arrangement of the second through hole and the convex portion of the first diaphragm together improves the signal-to-noise ratio of the MEMS structure.

Since the connection between the top surface and the side surface of the convex portion of the first diaphragm is arc-shaped, the stress of the diaphragm of the first diaphragm is further released, thereby improving the sensitivity of the micro-electromechanical structure.

By arranging a plurality of anti-adhesion parts on the side of the first back plate facing the first diaphragm and staggered from the convex part, the anti-adhesion part can not only prevent the anti-adhesion part from touching the convex part of the first diaphragm, but also effectively prevent the The adhesion of the first back plate and the first diaphragm improves the mechanical reliability of the MEMS structure.

In the vertical direction, when the first diaphragm and the first back plate are relatively stationary, starting from the surface of the non-convex part of the first diaphragm, the distance to the convex part of the first diaphragm is smaller than that to the first diaphragm Therefore, when the vibration amplitude of the first diaphragm is small, the convex part of the first diaphragm will not protrude into the through hole of the first back plate, which reduces the damping of the airflow flowing through the back plate to reduce noise. Further, since the size of the first diaphragm protrusion is smaller than the size of the corresponding first back plate through hole, when the vibration amplitude of the first diaphragm is relatively large, even if the first diaphragm protrusion extends into the corresponding In the through hole, the raised portion of the first diaphragm is not easy to touch the side wall of the through hole, thus reducing the risk of damage to the first diaphragm and improving the mechanical reliability of the MEMS structure.

Further, the plurality of first protrusions are only corresponding to the central area, and the orthographic projection of the first conductive layer on the first diaphragm falls in the central area, because at the central area, the deformation of the first diaphragm is Therefore, the capacitance formed by the central area of the first diaphragm and the first conductive layer has a large variation range; and at the edge area, the deformation energy of the first diaphragm is relatively weak. For the edge area of the first diaphragm and the For the capacitor formed by the first conductive layer, its variation range is small, and it does not contribute much to the overall sound airflow response. Therefore, the positions of the first conductive layer and the first protruding portion correspond to the central region of the first diaphragm, and the first conductive layer is no longer formed in the edge region. In the first backplane, the first through hole with a smaller size corresponds to the first conductive layer, and the second through hole with a larger size does not need to penetrate the first conductive layer, but is only located in the first insulating layer at the edge, and further The acoustic resistance is reduced, and the effect of increasing the fringe capacitance is obvious, and the signal-to-noise ratio will be further improved.

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

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present disclosure more clearly, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limit the present disclosure. .

FIG. 1 is a schematic three-dimensional structure diagram of a microelectromechanical structure according to a first embodiment of the disclosure.

FIG. 2 is a schematic three-dimensional structure diagram of FIG. 1 after the first backplane is hidden.

FIG. 3 is a schematic three-dimensional structure diagram 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 view of the structure in the dotted frame in FIG. 4 .

FIG. 6 is a schematic top view of the structure of the first backplane in FIG. 1 .

7 to 9 are schematic diagrams of capacitor fringing effects.

FIG. 10 is a schematic diagram of a MEMS structure according to a second embodiment of the disclosure.

FIG. 11 is a schematic diagram of a MEMS structure according to a third embodiment of the disclosure.

FIG. 12 is a schematic diagram of a MEMS structure according to a fourth embodiment of the disclosure.

FIG. 13 is a schematic diagram of a MEMS 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 disclosure.

Detailed ways

The present disclosure will be described in more detail below with reference to the accompanying drawings. In the various figures, like elements are designated by like reference numerals. For the sake of clarity, various parts in the figures have not been drawn to scale. Additionally, some well-known parts may not be shown. For the sake of simplicity, the semiconductor structure obtained after several steps can be depicted in one figure.

It will be understood that, in describing the structure of a device, when a layer or region is referred to as being "on" or "over" another layer or region, it can be directly on the other layer or region, or Other layers or regions are also included between it and another layer, another region. And, if the device is turned over, the layer, one region, will be "under" or "under" another layer, another region.

Numerous specific details of the present disclosure are described below, such as device structures, materials, dimensions, processing techniques and techniques, in order to provide a clearer understanding of the present disclosure. However, as can be understood by one 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 FIGS. 1 to 6 , the MEMS structure of the first embodiment of the present disclosure includes: a substrate 101 , a first support portion 111 , a second support portion 112 , a first diaphragm 120 , a first back plate 130 and multiple a through hole passing through the first backplane 130 . The substrate 101 has the cavity 10 . The first support portion 111 is located at the edge on the substrate 101 . The first diaphragm 120 is located on the first support portion 111 and covers the cavity 10 . The second support portion 112 is located on the first diaphragm 120 , and the position corresponds to the first support portion 111 . The first back plate 130 is located on the second support portion 112 and has a gap with the first diaphragm 120 .

In this embodiment, the first support portion 111 is the portion left on the substrate 101 after the sacrificial layer is released. The first support portion 111 is located on the peripheral edge of the substrate 110 and adopts the peripheral edge fully clamped method. The first diaphragm 120 located above the first support portion 111 is supported on the substrate 101 . The second support portion 112 is the part that remains on the first diaphragm 120 after the sacrificial layer is released. The second support portion 112 is located on the peripheral edge of the first diaphragm 120, and the peripheral edge is fully clamped to be located on the first diaphragm 120. The first back plate 130 above the second support portion 112 is supported and fixed. However, the embodiment of the present disclosure is not limited thereto, and those skilled in the art may perform other settings for the fixing manner among the substrate 101 , the first diaphragm 120 , and the first back plate 130 as required.

In some specific embodiments, the substrate 101 is a silicon substrate, and the cavity 10 is located in the middle of the substrate 101 and communicates with two opposite surfaces of the substrate 101 . Of course, the position and shape of the cavity 10 can be set by those skilled in the art as required, which is not limited here. The materials of the first support portion 111 and the second support portion 112 are insulating materials, including but not limited to silicon oxide.

Further, the first backplane 130 includes a first insulating layer 131 and a first conductive layer 132 , which are stacked on the second supporting portion 112 along the thickness direction of the substrate 101 . The material of the first insulating layer 131 includes but not limited to silicon nitride, and the material of the first conductive layer 132 includes but 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 area of the diaphragm 120 . However, the embodiment of the present disclosure is not limited to this, and those skilled in the art can make other settings for the material and structure of the first backplane 130 as required, for example, the first backplane 130 is configured as a structure with two insulating layers sandwiching a conductive layer. structure, or using only one conductive layer to form the first backplane 130 and so on.

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

In this 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 in the middle of the back plate 130 corresponding to the central area S1 , and the plurality of first through holes 11 The two through holes 12 surround the plurality of first through holes 11 corresponding to the edge regions S2 , and the size of each second through hole 12 is larger than that of the first through hole 11 . The plurality of first through holes 11 and the plurality of second through holes 12 pass through the first conductive layer 132 and the first insulating layer 131 , the first through holes 11 and the second through holes 12 are round holes, and the first through holes The size of the 11 and the second through hole 12 is the diameter of the hole. Of course, those skilled in the art can make other settings for the shape of the through hole as required.

In some specific embodiments, along the direction from the center to the edge of the first backplane 130 , the sizes of the plurality of second through holes 12 gradually increase, as shown in FIG. 6 . Since the deformation ability 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 is smaller as it is closer to the center and closer to the edge. The larger the size of the through hole is, the damping can be reduced by using the second through hole 12 whose size gradually increases without affecting the sensitivity of the MEMS structure as much as possible. However, the present embodiment is not limited thereto, and those skilled in the art can perform other settings for the size change of the second through hole 12 as required.

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, at least one of the plurality of first convex portions 120a and the plurality of first through holes 11 and/or the plurality of second through holes 12 . Partial correspondence.

In this embodiment, the second support portion 112 corresponds to the fixed area at the periphery of the active area of the first diaphragm 120 , and is in contact with the non-convex portion 120 b of the first diaphragm 120 . Along 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<h2. It can also be understood as: in the vertical direction, when the first diaphragm 120 and the first back plate 130 are relatively stationary, the surface of the non-convex part 120b of the first diaphragm 120 is taken as the starting point to reach the first convex The vertical distance of the raised portion 120 a is smaller than the distance to the lower surface of the first backplane 130 . When the vibration amplitude of the first diaphragm 120 is small, the first protruding portion 120a will not protrude into the through hole of the first back plate 130, which reduces the damping of the airflow flowing through the first back plate 130 to reduce noise; When the vibration amplitude of the first diaphragm 120 is relatively large, even if the first protruding portion 120a protrudes into the corresponding through hole, the first protruding portion 120a is not easy to touch the side wall of the through hole, thus reducing the vibration. The risk of damage to the first diaphragm 120 improves the mechanical reliability of the MEMS structure. In some specific embodiments, h1≤0.5h2.

In this embodiment, each first protruding portion 120a corresponds to a through hole (including the first through hole 11 and the second through hole 12 ) on the back plate 130 one-to-one, and the first protruding portion 120a corresponds to the corresponding through hole are similar in shape, for example, the through hole is a circular hole, and the first protrusion 120a is a circular protrusion. In some other embodiments, the first protruding portion 120 a may only correspond to the first through hole 11 , or only correspond to the second through hole 12 . As shown in FIG. 5 , the conductive layer 132 of the first backplane 130 not only forms a capacitor C1 at the bottom facing the first diaphragm 120 , but also forms an additional capacitor C2 in parallel with the capacitor C1 due to the edge effect of the capacitor. The edge effect of the capacitor will be described in detail below with reference to FIGS. 7 to 9 .

As shown in FIG. 7 and FIG. 8 , the first conductive layer 132 of the first backplane 130 and the first diaphragm 120 can be regarded as a parallel plate capacitor. In the middle part of the parallel plate capacitor, the electric field lines are evenly distributed, but at the edges The distribution of the electric field lines is not uniform, causing the edge effect of the capacitor, which is equivalent to connecting a C2 in parallel next to the capacitor C1. As shown in FIG. 9 , when the convex portion is provided in the first diaphragm 120 , compared with the first diaphragm 120 without the convex portion, the convex surface on which the convex portion is provided reaches the first back plate 130 . The vertical distance of the hole edge is shortened, so the additional capacitance C2 due to the capacitor fringing effect increases. Therefore, when the second through hole 12 with a larger size is provided, it is ensured that the capacitance value between the first back plate 130 and the first diaphragm 120 can reach a preset value. Along the thickness direction of the first vibrating film 120 , the cross-section of the first vibrating film 120 is corrugated, and the cross-sections of the plurality of first protruding portions 120 a are the crests of the corrugation. The dimension d2 of at least part of the plurality of first through holes 11 and/or the plurality of second through holes 12 is larger than the dimension d1 of the corresponding first protrusion 120a. In some preferred embodiments, the connection between the top surface and the side surface of the first protruding portion 120a is arc-shaped, which further relieves the stress of the first diaphragm 120 and improves the sensitivity of the MEMS structure.

Further, the MEMS structure of this embodiment further includes a plurality of anti-sticking parts 140, which are located on the side of the first back plate 130 facing the first diaphragm 120, so that the anti-sticking parts 140 do not touch the first protrusions The portion 120a also effectively prevents the first backplane 130 from adhering to the first diaphragm 120, thereby improving the mechanical reliability of the MEMS structure.

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

FIG. 10 is a schematic diagram of a MEMS structure according to a second embodiment of the disclosure.

As shown in FIG. 10 , the MEMS structure of the second embodiment of the present disclosure is similar to that of the first embodiment, and the descriptions of FIGS. 1 to 9 may be referred to, and the same points will not be repeated. The difference from the first embodiment is that the plurality of first protrusions 120a in this embodiment are only located in the central area S1, and the orthographic projection of the first conductive layer 132 on the first diaphragm 120 falls in the central area. within S1.

Since the deformation ability of the first diaphragm 120 gradually increases along the direction from the edge to the center of the first diaphragm 120, at the central area S1, the deformation ability of the first diaphragm 120 is strong, so the center of the first diaphragm 120 has a strong deformation ability. The capacitance formed by the area S1 and the first conductive layer 132 has a large variation range, and the capacitance formed by the central area S1 of the first diaphragm 120 and the first conductive layer 132 can be regarded as an effective capacitance; and at the edge area S2, the first The deformation energy of the diaphragm 120 is relatively weak, and for the capacitance formed by the edge region S2 of the first diaphragm 120 and the first conductive layer 132 , the variation range is small, and it does not contribute much to the overall sound airflow response. Therefore, in this embodiment, the positions of the first conductive layer 132 and the first protruding portion 120a correspond to the central area S1 of the first diaphragm 120, and the first conductive layer 132 and the first conductive layer 132 and the first The raised portion 120a. In the first backplane 130 , the first through holes 11 with a smaller size correspond to the first conductive layer 132 , and the second through holes 12 with a larger size do not need to penetrate the first conductive layer 132 , and the second through holes 12 only in the first insulating layer 131 at the edge. Compared with the first embodiment, the MEMS structure of this embodiment further reduces the acoustic resistance, and the effect of increasing the fringe capacitance is obvious, and the signal-to-noise ratio is further improved.

FIG. 11 is a schematic diagram of a MEMS structure according to a third embodiment of the disclosure.

As shown in FIG. 11 , the MEMS structure of the third embodiment of the present disclosure is similar to that of the first embodiment, and the descriptions in FIGS. 1 to 9 may be referred to, and the same points will not be 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 diagram of a MEMS structure according to a fourth embodiment of the disclosure.

As shown in FIG. 12 , the MEMS structure of the fourth embodiment of the present disclosure is similar to that of the first embodiment, and the descriptions in FIGS. 1 to 9 may be referred to, and the same points will not be repeated. The difference from the first embodiment is that the structure of the microcomputer in this embodiment further includes a second backplane 150 and a third support portion 113 . Along the thickness direction of the substrate 101 , the first support portion 111 , the second back plate 150 , the second support portion 112 , the first diaphragm 120 , the third support portion 113 and the first back plate 130 are sequentially stacked on the substrate 101 . The plurality of third through holes 13 penetrate through the second back plate 150 , and the plurality of first protrusions 120 a and the plurality of third through holes 13 are staggered from each other. In this embodiment, the material of the third support portion 113 includes but not limited to silicon oxide, and the material and structure of the second backplane 150 are similar to those of the first backplane 130 , including the connected second insulating layer 152 and the second conductive layer. 151. Of course, those skilled in the art can make other settings for the material and structure of the second backplane 150 as required. In this embodiment, the third support portion 113 is in contact with the non-convex portion of the second diaphragm 160 , and along the thickness direction of the second diaphragm 160 , the non-convex portion of the second diaphragm 120 reaches the second convex portion The distance from the surface of 160 a is smaller than the thickness of the third support portion 113 .

FIG. 13 is a schematic diagram of a MEMS structure according to a fifth embodiment of the disclosure.

As shown in FIG. 13 , the MEMS structure of the fifth embodiment of the present disclosure is similar to that of the first embodiment, and the descriptions in FIGS. 1 to 9 may be referred to, and the same points will not be repeated. The difference from the first embodiment is that the MEMS structure in this embodiment further includes a second diaphragm 160 and a third support portion 113 , and the first backplane 130 further includes an insulating layer 133 , which is separate from the insulating layer 131 . on opposite sides of the conductive layer 132 . The third support portion 113 is the part that remains on the first backplane 130 after the sacrificial layer is released. The third support portion 113 is located on the peripheral edge of the first backplane 130 , and the peripheral edge is fully clamped to hold the portion located on the first backplane 130 . The second diaphragm 160 above the third support portion 113 is supported and fixed. 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 protrusions 160 a corresponding to at least part of the plurality of first through holes 11 and/or the plurality of second through holes 12 . Along the thickness direction of the second diaphragm 160 , the cross-section of the second diaphragm 160 is corrugated, and the cross-sections of the plurality of second protrusions 160 a are the troughs of the corrugation. The size of at least part of the plurality of first through holes 11 and/or the plurality of second through holes 12 is larger than the size of the corresponding second protrusions 160a. Preferably, the connection between the top surface and the side surface of the second protruding portion 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: a micro-electromechanical structure 100 , a chip structure 200 , a substrate 300 , and a housing 400 . The substrate 300 and the casing 400 serve as the packaging structure of the device. The microelectromechanical structure 100 of 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 this embodiment, the pads of the MEMS structure 100 are electrically connected to the chip structure 200 , the substrate 300 and the casing 400 of the package structure are used to form the accommodating cavity of the package structure, and the MEMS structure 100 and the chip structure 200 are located in the accommodating cavity Inside.

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

According to the microelectromechanical structure provided by the embodiments of the present disclosure, by arranging the second through hole with a larger size on the first backplane, the damping of the airflow flowing through the through hole of the first backplane is reduced, thereby reducing the MEMS structure. Although increasing the size of the through hole will correspondingly reduce the facing area between the first backplate and the active area of the first diaphragm, resulting in a reduction in capacitance and a reduction in the sensitivity of the MEMS structure, the smaller size of the first The through hole corresponds to the central area of the active area of the first diaphragm, the second through hole with a larger size corresponds to the edge area of the active area of the first diaphragm, and the deformation ability of the edge area of the active area of the first diaphragm is compared to The center area is small, so setting a large-sized second through hole on the first back plate corresponding to the edge area of the first diaphragm active area has little effect on the overall sensitivity of the MEMS structure; at the same time, due to the convexity of the first diaphragm The additional capacitance increased by the part can make up for the reduced capacitance due to the reduced facing area. In the case where the area of the first diaphragm and the first back plate is limited, compared with the first diaphragm without the convex part, The vertical distance from the surface of the first diaphragm with the raised portion to the edge of the through hole of the first backplane is shortened, so the additional capacitance caused by the capacitor edge effect increases, thus ensuring the connection between the first backplane and the first diaphragm. The total capacitance value between the two can reach the preset value, so that the sensitivity of the MEMS structure can meet the preset requirements. Therefore, the arrangement of the second through hole and the convex portion of the first diaphragm together improves the signal-to-noise ratio of the MEMS structure.

Since the connection between the top surface and the side surface of the convex portion of the first diaphragm is arc-shaped, the stress of the diaphragm of the first diaphragm is further released, thereby improving the sensitivity of the micro-electromechanical structure.

By arranging a plurality of anti-sticking parts on the side of the first back plate facing the vibrating membrane and staggering from the protruding part, the anti-sticking part can not only prevent the anti-sticking part from touching the protruding part of the first vibrating membrane, but also effectively prevent the first vibrating membrane. The adhesion of the back plate and the first diaphragm improves the mechanical reliability of the MEMS structure.

In the vertical direction, when the first diaphragm and the first back plate are relatively stationary, starting from the surface of the non-convex part of the first diaphragm, the distance to the convex part of the first diaphragm is smaller than that to the first diaphragm Therefore, when the vibration amplitude of the first diaphragm is small, the convex part of the first diaphragm will not protrude into the through hole of the first back plate, which reduces the damping of the airflow flowing through the back plate to reduce noise. Further, since the size of the first diaphragm protrusion is smaller than the size of the corresponding first back plate through hole, when the vibration amplitude of the first diaphragm is relatively large, even if the first diaphragm protrusion extends into the corresponding In the through hole, the raised portion of the first diaphragm is not easy to touch the side wall of the through hole, thus reducing the risk of damage to the first diaphragm and improving the mechanical reliability of the MEMS structure.

Further, the plurality of first protrusions are only corresponding to the central area, and the orthographic projection of the first conductive layer on the first diaphragm falls in the central area, because at the central area, the deformation of the first diaphragm is Therefore, the capacitance formed by the central area of the first diaphragm and the first conductive layer has a large variation range; and at the edge area, the deformation energy of the first diaphragm is relatively weak. For the edge area of the first diaphragm and the For the capacitor formed by the first conductive layer, its variation range is small, and it does not contribute much to the overall sound airflow response. Therefore, the positions of the first conductive layer and the first protruding portion correspond to the central region of the first diaphragm, and the first conductive layer is no longer formed in the edge region. In the first backplane, the first through hole with a smaller size corresponds to the first conductive layer, and the second through hole with a larger size does not need to penetrate the first conductive layer, but is only located in the first insulating layer at the edge, and further The acoustic resistance is reduced, and the effect of increasing the fringe capacitance is obvious, and the signal-to-noise ratio will be further improved.

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

In the above description, technical details such as patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not exactly the same as those described above. Additionally, although the various embodiments have been described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

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 present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present disclosure.

Claims (21)

1. a microelectromechanical structure, is characterized in that, comprises: the first diaphragm; a first back plate, opposite to the surface of the first diaphragm; and a plurality of through holes penetrating the first backplane, The first diaphragm includes a plurality of first protrusions corresponding to at least part of the plurality of through holes, The first diaphragm includes an active area, and the active area includes a central area and an edge area surrounding the central area; The plurality of through holes include a plurality of first through holes and a plurality of second through holes, the plurality of first through holes correspond to the central area, the plurality of second through holes correspond to the edge area, and the The size of the plurality of second through holes is larger than the size of the plurality of first through holes. 2 . The MEMS structure according to claim 1 , wherein the distance from the center of the central area to the edge of the central area is R1 , and the distance from the center of the active area to the edge of the active area is R1 . is R2, the ratio of R1 to R2 is less than or equal to 3:4, The center area coincides with the center of the active area. 3 . The MEMS structure according to claim 1 , wherein, along the thickness direction of the first diaphragm, at least one section of the first diaphragm is corrugated, and the plurality of first protrusions The section of the section is the crest or trough of the corrugation. 4 . The MEMS structure according to claim 1 , wherein the connection between the top surface and the side surface of at least one of the first protruding parts is arc-shaped. 5 . 5. The micro-electromechanical structure according to claim 1, characterized in that it comprises a plurality of anti-sticking parts, which are located on the side of the first back plate facing the first diaphragm, and are connected with the plurality of first protrusions. Start staggered. 6. The micro-electromechanical structure according to any one of claims 1-5, characterized in that it comprises a second support portion located between the first diaphragm and the first back plate, the second support 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-convex portion of the first diaphragm to the surface of the first convex portion is smaller than the thickness of the second support portion. 7 . The MEMS structure according to claim 6 , wherein the vertical distance from the non-convex portion of the first diaphragm to the surface of the first convex portion is h1 . Thickness is h2, h1≤0.5h2. 8 . The MEMS structure according to claim 6 , wherein the size of at least part of the plurality of through holes is larger than the size of the corresponding first protrusion. 9 . 9 . The MEMS structure according to claim 1 , wherein the plurality of first protrusions are located only in the central area. 10 . 10. The MEMS structure according to claim 9, wherein the first backplane comprises a first insulating layer and a first conductive layer, The first diaphragm and the first conductive layer are respectively located on opposite sides of the first insulating layer, The size of the first conductive layer is smaller than that of the first insulating layer, and the orthographic projection of the first conductive layer on the first diaphragm falls in the central area. 11 . The microelectromechanical structure according to claim 1 , wherein, along the direction from the center to the edge of the first backplane, the size of the plurality of second through holes gradually increases. 12 . 12. The micro-electromechanical structure according to any one of claims 1-5, characterized in that it comprises a second back plate, which is located on opposite sides of the first diaphragm from the first back plate, respectively. 13. The microelectromechanical structure according to claim 12, characterized in that it comprises a plurality of third through holes penetrating the second backplane, The plurality of first protrusions and the plurality of third through holes are staggered from each other. 14. The MEMS structure according to any one of claims 1-5, characterized in that it comprises a second diaphragm, which is located on opposite sides of the first backplane from the first diaphragm, respectively. 15 . The MEMS structure of claim 14 , wherein the second diaphragm comprises a plurality of second protrusions corresponding to at least part of the plurality of through holes. 16 . 16 . The MEMS structure according to claim 15 , wherein, along the thickness direction of the second diaphragm, at least one section of the second diaphragm is corrugated, and the plurality of second protrusions The section of the section is the crest or trough of the corrugation. 17. The MEMS structure according to claim 14, characterized in that it comprises a third support portion located between the second diaphragm and the first back plate, the third support 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 portion of the second diaphragm to the surface of the second convex portion is smaller than the thickness of the third support portion. 18 . The MEMS structure of claim 15 , wherein the size of at least part of the plurality of through holes is larger than the size of the corresponding second protrusion. 19 . 19 . The MEMS structure according to claim 15 , wherein the connection between the top surface and the side surface of at least one of the second protrusions is arc-shaped. 20 . 20. A microphone, characterized by comprising the micro-electromechanical structure according to any one of claims 1-19. 21. A terminal, comprising the microphone of claim 20.

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