MEMS sensor, microphone module and electronic equipment

Abstract

The invention discloses an MEMS sensor, a microphone module and electronic equipment, and relates to the technical field of electronic equipment, the MEMS sensor comprises a substrate and at least one capacitor system arranged on the substrate, the capacitor system comprises a backboard, a first vibrating diaphragm and a second vibrating diaphragm, and the first vibrating diaphragm and the second vibrating diaphragm are arranged on the two sides of the backboard; a connecting column is arranged between the first vibrating diaphragm and the second vibrating diaphragm, and under the connection of the connecting column, the connecting rigidity between the first vibrating diaphragm and the second vibrating diaphragm is greater than the vibrating diaphragm bending rigidity of the first vibrating diaphragm and the second vibrating diaphragm; and / or, the distance between the back plate and the first vibrating diaphragm is a first polar plate distance, the distance between the back plate and the second vibrating diaphragm is a second polar plate distance, the first polar plate distance is in negative correlation with the vibrating diaphragm bending rigidity of the first vibrating diaphragm, and the second polar plate distance is in negative correlation with the vibrating diaphragm bending rigidity of the second vibrating diaphragm. The invention provides an MEMS sensor. The MEMS sensor solves the technical problem that the sensitivity of vibrating diaphragms of an existing MEMS sensor is inconsistent.

Description

Technical Field

[0001] The present application relates to the technical field of electronic devices, and particularly to a MEMS sensor, a microphone module and an electronic device. Background Art

[0002] MEMS (Micro-Electro-Mechanical System), also known as micro-electronic mechanical system, microsystem, micromachine, etc., refers to an independent intelligent system with dimensions in millimeters or even smaller. MEMS is widely used in electronic devices due to its high precision, miniaturization and other characteristics.

[0003] Due to the influence of its manufacturing process and sensor structure, it is difficult to maintain consistent in-plane stress between multiple layers of diaphragms in MEMS sensors, resulting in inconsistent sensitivities. That is, in existing MEMS sensors, due to the difficulty in making the internal stresses of multiple layers of diaphragms consistent, the sensitivities between the diaphragms of MEMS sensors are inconsistent. Summary of the Invention

[0004] The main object of the present application is to propose a MEMS sensor, a microphone module and an electronic device, aiming to solve the technical problem of inconsistent sensitivities between diaphragms of existing MEMS sensors.

[0005] To achieve the above object, a MEMS sensor proposed by the present application includes a substrate, and at least one capacitor system disposed on the substrate, the capacitor system including a backplane and a first diaphragm and a second diaphragm disposed on both sides of the backplane; A connecting column is disposed between the first diaphragm and the second diaphragm, and under the connection of the connecting column, the connection stiffness between the first diaphragm and the second diaphragm is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm; and / or, The distance between the backplane and the first diaphragm is a first plate spacing, and the distance between the backplane and the second diaphragm is a second plate spacing, where the first plate spacing is negatively correlated with the diaphragm bending stiffness of the first diaphragm, and the second plate spacing is negatively correlated with the diaphragm bending stiffness of the second diaphragm.

[0006] In an embodiment, a connecting column with a predetermined column density is disposed between the first diaphragm and the second diaphragm, and under the predetermined column density, the connection stiffness between the first diaphragm and the second diaphragm is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm.

[0007] In an embodiment, the distance between adjacent connecting columns is greater than 50 microns.

[0008] In one embodiment, the total number of connecting columns between the first diaphragm and the second diaphragm is less than 1000.

[0009] In one embodiment, through holes are formed in the back plate, and the connecting columns connect the first diaphragm and the second diaphragm through the through holes.

[0010] In one embodiment, micropores exist on the first diaphragm and the second diaphragm.

[0011] In one embodiment, the first diaphragm and the second diaphragm form a sealed cavity.

[0012] In one embodiment, a first insulating layer is provided between the substrate and the capacitor system; A second insulating layer is provided between the back plate and the first diaphragm; A third insulating layer is provided between the back plate and the second diaphragm.

[0013] The present application also provides a microphone module, which includes a packaging shell; and the MEMS sensor as described above, and the MEMS sensor is disposed in the packaging shell.

[0014] The present application also provides an electronic device, which includes the microphone module as described above.

[0015] In the technical solution of the present application, the MEMS sensor includes a substrate, and at least one capacitor system disposed on the substrate. The capacitor system includes a backplane and a first vibrating membrane and a second vibrating membrane disposed on both sides of the backplane. Thus, the first vibrating membrane and the backplane form a first capacitor, and the second vibrating membrane and the backplane form a second capacitor, so that the recognition of external excitations (such as sound, pressure, etc.) can be achieved through the capacitance changes of the first capacitor and the second capacitor. Furthermore, in the present application, a connecting post is disposed between the first vibrating membrane and the second vibrating membrane. Under the connection of the connecting post, the connection stiffness between the first vibrating membrane and the second vibrating membrane is greater than the vibrating membrane bending stiffness of the first vibrating membrane and the second vibrating membrane. Therefore, with the help of the connecting post with high connection stiffness, the vibration amplitudes of the first vibrating membrane and the second vibrating membrane become more convergent, thereby improving the mechanical sensitivity consistency of each vibrating membrane, and at the same time enhancing the mechanical strength of the vibrating membrane. In addition, in the present application, the distance between the backplane and the first vibrating membrane is the first plate distance, and the distance between the backplane and the second vibrating membrane is the second plate distance. Among them, the first plate distance is negatively correlated with the vibrating membrane bending stiffness of the first vibrating membrane, and the second plate distance is negatively correlated with the vibrating membrane bending stiffness of the second vibrating membrane. Since the capacitance of the capacitor increases as the plate distance of the capacitor decreases, in the present application, for the vibrating membrane with a greater vibrating membrane bending stiffness (smaller displacement under the same external force), a smaller plate distance is adopted to obtain a larger voltage change under the same displacement amplitude, and for the vibrating membrane with a smaller vibrating membrane bending stiffness (larger displacement under the same external force), a larger plate distance is adopted to obtain a smaller voltage change under the same displacement amplitude, so that the displacement amounts of the vibrating membranes with different vibrating membrane bending stiffnesses are different under the same external force, but the capacitance change amounts tend to be the same, improving the electrical sensitivity consistency of each vibrating membrane of the MEMS sensor. In summary, the present application can improve at least one of the mechanical sensitivity and electrical sensitivity of each vibrating membrane of the MEMS sensor, thereby improving the sensitivity between each vibrating membrane of the MEMS sensor. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0017] Figure 1 It is a schematic structural diagram of an embodiment of the MEMS sensor provided by the present application; Figure 2 It is a schematic diagram of the forces on the equivalent physical model of the MEMS sensor involved in the embodiment of the present application; Figure 3 3D schematic diagram of an embodiment of the MEMS sensor provided in this application; Figure 4 3D schematic diagram of another embodiment of the MEMS sensor provided in this application; Figure 5 Structural schematic diagram of an embodiment of the triple diaphragm sensor provided in this application; Figure 6 Diaphragm displacement nephogram under the same external excitation involved in the embodiment of this application; Figure 7 Structural schematic diagram of another embodiment of the MEMS sensor provided in this application; Figure 8 Structural schematic diagram of another embodiment of the triple diaphragm sensor provided in this application; Figure 9 Structural schematic diagram of yet another embodiment of the MEMS sensor provided in this application; Figure 10 Structural schematic diagram of still another embodiment of the MEMS sensor provided in this application; Figure 11 Structural schematic diagram of the diaphragm involved in the embodiment of this application; Figure 12 Structural schematic diagram of an embodiment of the MEMS sensor involved in the embodiment of this application.

[0018] Explanation of the reference numerals in the drawings: 110, substrate; 120, backplane; 130, first diaphragm; 140, second diaphragm; 150, connecting column; 160, first insulating layer; 170, second insulating layer; 180, third insulating layer.

[0019] The realization of the purpose of this application, functional features and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope protected by this application.

[0021] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of this application, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0022] In addition, if the embodiments of this application involve descriptions such as "first" and "second", the descriptions of "first", "second", etc. are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0023] This application proposes a MEMS sensor.

[0024] Please refer to Figure 1 , in an embodiment of this application, the MEMS sensor includes a substrate 110, and at least one capacitor system disposed on the substrate 110. The capacitor system includes a backplane 120 and a first diaphragm 130 and a second diaphragm 140 disposed on both sides of the backplane 120; A connecting column 150 is disposed between the first diaphragm 130 and the second diaphragm 140. Under the connection of the connecting column, the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm; and / or, The distance between the backplane 120 and the first diaphragm 130 is the first plate distance, and the distance between the backplane 120 and the second diaphragm 140 is the second plate distance. The first plate distance is negatively correlated with the diaphragm bending stiffness of the first diaphragm 130, and the second plate distance is negatively correlated with the diaphragm bending stiffness of the second diaphragm 140.

[0025] It should be noted that the MEMS sensor can be a sensor with at least two diaphragms such as a sound sensor or a pressure sensor.

[0026] See Figure 2 , Figure 2This is a force diagram of the equivalent physical model of the MEMS sensor involved in the embodiments of the present application. In the figure, P is an external excitation (such as sound, pressure), m1 is the first diaphragm 130, m2 is the second diaphragm 140, k1 is the diaphragm bending stiffness of the first diaphragm 130, k2 is the diaphragm bending stiffness of the second diaphragm 140, k3 is the connection stiffness between the first diaphragm 130 and the second diaphragm 140, λ1 is the damping between the first diaphragm 130 and the outside, λ2 is the damping between the second diaphragm 140 and the outside, and λ3 is the damping between the first diaphragm 130 and the second diaphragm 140. Under the external excitation P, the displacement of the first diaphragm 130 is x1, and the displacement of the second diaphragm 140 is x2. Therefore, when the diaphragm stress is small, the diaphragm bending stiffness is small, resulting in a large displacement. On the contrary, when the diaphragm stress is large, the diaphragm bending stiffness is large, resulting in a small displacement. Thus, under the same external excitation P, different displacements of the diaphragm will cause different voltage changes, resulting in inconsistent sensitivities of different diaphragms.

[0027] In this embodiment, the MEMS sensor includes a substrate 110 and at least one capacitor system disposed on the substrate 110. The capacitor system includes a backplane 120 and the first diaphragm 130 and the second diaphragm 140 disposed on both sides of the backplane 120. Thus, a capacitor is formed between the backplane 120 and the first diaphragm 130 in the capacitor system, and another capacitor is formed between the backplane 120 and the second diaphragm 140. While the first diaphragm 130 and the second diaphragm 140 move under the external excitation, corresponding voltage changes are caused. Among them, as Figure 3 shown, through holes may be provided on the first diaphragm 130 and / or the second diaphragm 140. As Figure 4 shown, through holes may not be provided on the first diaphragm 130 and the second diaphragm 140 to form a sealed cavity. Among them, the backplane 120 may be a multi-layer structure, and the multi-layer structure includes a conductive layer and insulating layers coated on both sides of the conductive layer to prevent short circuits when the first diaphragm 130 and the second diaphragm 140 come into contact with the backplane 120. Openings may be provided on the backplane 120 to reduce air resistance, and the backplane 120 can provide support for the first diaphragm 130 and the second diaphragm 140 to improve the reliability of the sensor. The backplane 120 may also be a single-layer structure, that is, only a conductive layer, and insulating layers need to be additionally provided on both sides of the backplane 120 to prevent capacitor short circuits. In addition, the MEMS sensor of this embodiment may be a three-diaphragm sensor (that is, the MEMS sensor includes two capacitor systems disposed on the substrate 110), a four-diaphragm sensor (that is, the MEMS sensor includes three capacitor systems disposed on the substrate 110), etc., which are MEMS sensors with multiple capacitor systems. As Figure 5As shown, taking the MEMS sensor as an example, the MEMS sensor can be a triple vibrating membrane sensor. The MEMS sensor includes a substrate 110, and two capacitor systems disposed on the substrate 110. The capacitor system includes a backplane 120 and a first vibrating membrane 130 and a second vibrating membrane 140 disposed on both sides of the backplane 120. Thus, in one of the capacitor systems, a capacitor is formed by the backplane 120 and the first vibrating membrane 130, and another capacitor is formed by the backplane 120 and the second vibrating membrane 140. It can be understood that the second vibrating membrane 140 in the lower capacitor system can be the first vibrating membrane 130 in the upper capacitor system. Thus, by increasing the distribution density of the connecting posts 150, the connection stiffness between the first vibrating membrane 130 and the second vibrating membrane 140 in each capacitor system can be improved.

[0028] As an example, in this embodiment, connecting posts 150 are provided between the first vibrating membrane 130 and the second vibrating membrane 140. Under the connection of the connecting posts 150, the connection stiffness between the first vibrating membrane 130 and the second vibrating membrane 140 is greater than the vibrating membrane bending stiffness of the first vibrating membrane and the second vibrating membrane. Exemplarily, in this embodiment, the connection stiffness between the first vibrating membrane 130 and the second vibrating membrane 140 under the connection of the connecting posts 150 can be improved by at least one of the following methods: increasing the density of the connecting posts 150, increasing the cross-sectional area of the connecting posts 150, and using a material with higher stiffness, so that the connection stiffness is greater than the vibrating membrane bending stiffness of the first vibrating membrane and the second vibrating membrane.

[0029] As Figure 6 shown, Figure 6 In the left figure in, the vibrating membrane displacement nephogram of the basic structure is shown. The sensitivity of the first vibrating membrane 130 is higher, and the sensitivity of the second vibrating membrane 140 is lower. Figure 6 In the right figure in, the vibrating membrane displacement nephogram of the encrypted connecting post structure is shown. That is, in this example, by increasing the column density of the connecting posts 150, the connection stiffness between the first vibrating membrane 130 and the second vibrating membrane 140 is improved, and the mechanical sensitivities of the first vibrating membrane 130 and the second vibrating membrane 140 are basically the same. The mechanical sensitivity refers to the degree of response of the vibrating membrane to mechanical vibration, that is, the ratio between the vibrating membrane displacement and the pressure applied by the external excitation. As shown in the following table, the following table shows the mechanical sensitivities under different structures:

[0030] Under the basic structure (i.e., the structure of the existing MEMS sensor), the mechanical sensitivity ratio between the second diaphragm 140 and the first diaphragm 130 is 70%, and the consistency between the two is relatively low. Under the encrypted connection column structure, the mechanical sensitivity ratio between the second diaphragm 140 and the first diaphragm 130 is 99%, and they are basically completely consistent. In this embodiment, the density of the connection columns 150 between the multiple diaphragms can be increased to improve the connection stiffness between the first diaphragm 130 and the second diaphragm 140, and the consistency of the mechanical sensitivity of the diaphragms can be enhanced. Thus, in this embodiment, connection columns 150 are provided between the first diaphragm 130 and the second diaphragm 140. Under the connection of the connection columns 150, the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm. Therefore, in this embodiment, with the connection columns 150 having high connection stiffness, the vibration amplitudes of the first diaphragm 130 and the second diaphragm 140 become more convergent, thereby improving the mechanical sensitivity consistency of each diaphragm and enhancing the mechanical strength of the diaphragm at the same time.

[0031] As another example, in this embodiment, the distance between the backplane 120 and the first diaphragm 130 is the first plate distance, and the distance between the backplane 120 and the second diaphragm 140 is the second plate distance. Among them, the first plate distance is negatively correlated with the diaphragm bending stiffness of the first diaphragm 130, and the second plate distance is negatively correlated with the diaphragm bending stiffness of the second diaphragm 140. In this embodiment, under the same external excitation P, the displacement of the first diaphragm 130 is x1, and the displacement of the second diaphragm 140 is x2. Different displacements of the diaphragms will cause different voltage changes, resulting in inconsistent sensitivities of different diaphragms. As Figure 7 shown, in the capacitor system, a capacitor formed by the backplane 120 and the first diaphragm 130 is the first capacitor, and another capacitor formed by the backplane 120 and the second diaphragm 140 is the second capacitor. Assume that the first plate distance between the backplane 120 and the first diaphragm 130 is d1, and the second plate distance between the backplane 120 and the second diaphragm 140 is d2. The capacitance of the first capacitor , the capacitance C1 of the first capacitor is inversely proportional to the first plate distance d1, that is, the smaller the first plate distance d1, the larger the capacitance C1; similarly, the capacitance of the second capacitor , the capacitance C2 of the second capacitor is inversely proportional to the second plate distance d2, that is, the smaller the second plate distance d2, the larger the capacitance C2. The capacitance change of the first capacitor , the capacitance change of the second capacitor , since x1, x2 ≪ d1, d2, so (d1 - x1) ≈ d1, (d2 - x2) ≈ d2 can be used: The capacitance change of the first capacitor ; The capacitance change of the second capacitor 。

[0032] Thus, in this embodiment, by adjusting the first plate distance d1 and the second plate distance d2 such that d1 / d2 = x1 / x2, the electrical sensitivities of the first diaphragm 130 and the second diaphragm 140 are as follows: The electrical sensitivity Soc1 of the first diaphragm 130 = ; The electrical sensitivity Soc2 of the second diaphragm 140 = 。

[0033] where V bias is the bias voltage. Therefore, when d1 / d2 = x1 / x2, the electrical sensitivity Soc1 of the first diaphragm 130 = the electrical sensitivity Soc2 of the second diaphragm 140.

[0034] It can be seen from this that in this embodiment, by adjusting the symmetry value of the connecting column 150, under the same external excitation, the plate spacing of the capacitor corresponding to the diaphragm with a smaller displacement (i.e., a larger diaphragm bending stiffness) is reduced, and then the capacitance of this capacitor increases per unit displacement. Similarly, under the same external excitation, the plate spacing of the capacitor corresponding to the diaphragm with a larger displacement (i.e., a smaller diaphragm bending stiffness) is increased, and then the capacitance of this capacitor decreases per unit displacement. The symmetry value of the connecting column 150 is an index value describing the degree of symmetry between the first plate spacing d1 and the second plate spacing d2. The symmetry value can be the ratio between the first plate spacing d1 and the second plate spacing d2, that is, N = d1 / d2. Or the symmetry value can also be the value obtained by normalizing the absolute value of the spacing difference between the first plate spacing d1 and the second plate spacing d2. Exemplarily, N=(1 - |(d1 - d2)| / (d1 + d2)). Thus, in this embodiment, the spacing between the backplane 120 and the first diaphragm 130 is the first plate spacing, and the spacing between the backplane 120 and the second diaphragm 140 is the second plate spacing. Among them, the first plate spacing is negatively correlated with the diaphragm bending stiffness of the first diaphragm 130, and the second plate spacing is negatively correlated with the diaphragm bending stiffness of the second diaphragm 140. Since the capacitance of the capacitor increases as the plate spacing of the capacitor decreases, in this embodiment, for the diaphragm with a larger diaphragm bending stiffness (smaller displacement under the same external force), a smaller plate spacing is adopted to obtain a larger voltage change under the same amplitude of displacement, and for the diaphragm with a smaller diaphragm bending stiffness (larger displacement under the same external force), a larger plate spacing is adopted to obtain a smaller voltage change under the same amplitude of displacement, so that the displacement amounts of the diaphragms with different diaphragm bending stiffnesses are different under the same external force, but the capacitance change amounts tend to be the same, improving the electrical sensitivity consistency of each diaphragm of the MEMS sensor. Similarly, this embodiment can also be applied to MEMS sensors with multiple capacitor systems such as three-diaphragm sensors (i.e., the MEMS sensor includes two capacitor systems provided on the substrate 110) and four-diaphragm sensors (i.e., the MEMS sensor includes three capacitor systems provided on the substrate 110). As Figure 8 shown, taking the MEMS sensor as an example of a three-diaphragm sensor, this MEMS sensor includes a substrate 110 and two capacitor systems provided on the substrate 110. The capacitor system includes a backplane 120 and a first diaphragm 130 and a second diaphragm 140 provided on both sides of the backplane 120. Thus, a capacitor is formed between the backplane 120 and the first diaphragm 130 in one of the capacitor systems, and another capacitor is formed between the backplane 120 and the second diaphragm 140. It can be understood that the second diaphragm 140 in the lower capacitor system can be the first diaphragm 130 in the upper capacitor system. Thus, by adjusting the first plate spacing d1 and the second plate spacing d2, the electrical sensitivity consistency of each capacitor in the capacitor system is tuned.

[0035] It is understandable that in the first embodiment provided above, "a connecting column 150 is provided between the first diaphragm 130 and the second diaphragm 140. Under the connection of the connecting column 150, the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm", compared with the second embodiment "the distance between the back plate 120 and the first diaphragm 130 is the first plate distance, and the distance between the back plate 120 and the second diaphragm 140 is the second plate distance, where the first plate distance is negatively correlated with the diaphragm bending stiffness of the first diaphragm 130, and the second plate distance is negatively correlated with the diaphragm bending stiffness of the second diaphragm 140". Thus, in the first embodiment, by increasing the connection stiffness between the first diaphragm 130 and the second diaphragm 140, the mechanical sensitivity between the diaphragms is tuned, while in the second embodiment, by adjusting the distance between the back plate 120 and the first diaphragm 130 to be the first plate distance and the distance between the back plate 120 and the second diaphragm 140 to be the second plate distance, the electrical sensitivity between the diaphragms is tuned. The above are two feasible directions for tuning the sensitivity consistency between the diaphragms provided by the embodiments of the present application. This embodiment can adopt only one of them, or both can be adopted simultaneously. This embodiment does not make specific limitations on this. As Figure 9 shown, in this embodiment, the distribution density of the connecting column 150 can be increased synchronously, so that the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm, and at the same time, the distance between the back plate 120 and the first diaphragm 130 is adjusted to be the first plate distance d1, and the distance between the back plate 120 and the second diaphragm 140 is adjusted to be the second plate distance d2, which is matched with the diaphragm bending stiffness of the first diaphragm 130 and the second diaphragm 140.

[0036] In one embodiment, a connecting column 150 with a predetermined column density is provided between the first diaphragm 130 and the second diaphragm 140, where the connection stiffness between the first diaphragm 130 and the second diaphragm 140 under the predetermined column density is greater than the diaphragm bending stiffness of the first diaphragm 130 and the second diaphragm 140.

[0037] It should be noted that the predetermined column density is the distribution density of the connecting column 150 when the preset connection stiffness is greater than the diaphragm bending stiffness. It is understandable that the specific predetermined column density can be selected according to specific requirements due to the influence of factors such as the cross-sectional area of the connecting column, the diaphragm thickness, and the diaphragm bending stiffness.

[0038] As Figure 10As shown, in this embodiment, the distribution density of the connecting posts 150 between the first diaphragm 130 and the second diaphragm 140 is a predetermined column density. At the predetermined column density, the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is greater than the diaphragm bending stiffness of the first diaphragm 130 and the second diaphragm 140. Thus, in this embodiment, by adjusting the distribution density of the connecting posts 150, a high connection stiffness between the first diaphragm 130 and the second diaphragm 140 is achieved at the predetermined column density, so that the vibration amplitudes of the first diaphragm 130 and the second diaphragm 140 become more convergent, thereby improving the mechanical sensitivity consistency of each diaphragm. At the same time, the mechanical strength of the diaphragm can also be enhanced. Compared with the method of increasing the cross-sectional area of the connecting posts 150 or replacing with a high-stiffness material, the high-density connecting posts 150 in this embodiment are beneficial to dispersing local stress concentration and improving the stress uniformity, while high-stiffness materials may introduce brittleness problems, as well as higher material costs and processing costs.

[0039] In one embodiment, the distance between adjacent connecting posts 150 is greater than 50 micrometers.

[0040] Since the higher the density of the connecting posts 150, the higher the connection stiffness between the first diaphragm 130 and the second diaphragm 140, but too high a distribution density will also reduce the mechanical sensitivity to a certain extent. That is, the distance between adjacent connecting posts 150 is positively correlated with the mechanical sensitivity to a certain extent. Specifically, the greater the distance between adjacent connecting posts 150, the smaller the mechanical constraint on the diaphragm. When an external excitation acts on the diaphragm, it will cause the diaphragm to generate a greater displacement, thereby improving the mechanical sensitivity. On the contrary, the smaller the distance between adjacent connecting posts 150, the greater the mechanical constraint on the diaphragm. When an external excitation acts on the diaphragm, it will cause the displacement of the diaphragm to decrease and the mechanical sensitivity to decrease. Therefore, while tuning the sensitivity between the diaphragms of the MEMS sensor, it is also necessary to limit the distance between adjacent connecting posts 150 to be greater than 50 micrometers to avoid the mechanical sensitivity of the MEMS sensor being reduced due to too high a distribution density.

[0041] In one embodiment, the total number of connecting posts 150 between the first diaphragm 130 and the second diaphragm 140 is less than 1000.

[0042] Similarly, since the more the number of connecting posts 150, the higher the connection stiffness between the first diaphragm 130 and the second diaphragm 140, but too many connecting posts 150 will also reduce the mechanical sensitivity to a certain extent. Therefore, while tuning the sensitivity between the diaphragms of the MEMS sensor, it is also necessary to limit the number of connecting posts 150 to avoid the mechanical sensitivity of the MEMS sensor being reduced due to too many connecting posts 150.

[0043] In one embodiment, under the connection of the connecting column 150, the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is more than two orders of magnitude greater than the diaphragm bending stiffness of the first diaphragm 130 and the second diaphragm 140.

[0044] It can be understood that under the connection of the connecting column, if the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm, the vibration amplitudes of the first diaphragm 130 and the second diaphragm 140 can be made more convergent, and to a certain extent, the sensitivity consistency between the first diaphragm 130 and the second diaphragm 140 can be improved. However, in a scenario where the mechanical sensitivity consistency requirements for the first diaphragm 130 and the second diaphragm 140 are extremely high, the connection stiffness between the first diaphragm 130 and the second diaphragm 140 needs to be much greater than the diaphragm bending stiffness of the first diaphragm 130 and the second diaphragm 140, that is, the connection stiffness is at least two orders of magnitude greater than the diaphragm bending stiffness, which means the connection stiffness is at least more than 100 times greater than the diaphragm bending stiffness.

[0045] In one embodiment, through holes are formed in the back plate 120, and the connecting column 150 connects the first diaphragm 130 and the second diaphragm 140 through the through holes.

[0046] In one embodiment, as Figure 10 shown, there are micropores on the first diaphragm 130 and the second diaphragm 140.

[0047] In one embodiment, the first diaphragm 130 and the second diaphragm 140 form a sealed cavity.

[0048] As Figure 11 shown, in this embodiment, the first diaphragm 130 and the second diaphragm 140 can be set to be poreless, and thus a sealed cavity is formed between the first diaphragm 130 and the second diaphragm 140.

[0049] In one embodiment, a first insulating layer 160 is provided between the base 110 and the capacitor system; A second insulating layer 170 is provided between the back plate 120 and the first diaphragm 130; A third insulating layer 180 is provided between the back plate 120 and the second diaphragm 140.

[0050] As Figure 12 shown, in this embodiment, a first insulating layer 160 is provided between the base 110 and the capacitor system, a second insulating layer 170 is provided between the back plate 120 and the first diaphragm 130, and a third insulating layer 180 is provided between the back plate 120 and the second diaphragm 140. Thereby, the risk of short - circuit in the capacitor system is further reduced.

[0051] In the technical solution of the first embodiment of the present application, the MEMS sensor includes a substrate 110 and at least one capacitor system disposed on the substrate 110. The capacitor system includes a backplane 120 and a first diaphragm 130 and a second diaphragm 140 disposed on both sides of the backplane 120. Thus, the first diaphragm 130 and the backplane 120 form a first capacitor, and the second diaphragm 140 and the backplane 120 form a second capacitor, so that the recognition of external excitation (such as sound, pressure, etc.) can be realized through the capacitance change of the first capacitor and the capacitance change of the second capacitor. Furthermore, in this embodiment, a connecting column 150 is disposed between the first diaphragm 130 and the second diaphragm 140. Under the connection of the connecting column 150, the connection stiffness between the first diaphragm 130 and the second diaphragm 140 is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm. Therefore, in this embodiment, with the help of the connecting column 150 with high connection stiffness, the vibration amplitudes of the first diaphragm 130 and the second diaphragm 140 are more convergent, so that the consistency of the mechanical sensitivity of each diaphragm can be improved, and at the same time, the mechanical strength of the diaphragm can be enhanced. In addition, in this embodiment, the distance between the backplane 120 and the first diaphragm 130 is the first plate spacing, and the distance between the backplane 120 and the second diaphragm 140 is the second plate spacing. Among them, the first plate spacing is negatively correlated with the diaphragm bending stiffness of the first diaphragm 130, and the second plate spacing is negatively correlated with the diaphragm bending stiffness of the second diaphragm 140. Since the capacitance of the capacitor increases as the plate spacing of the capacitor decreases, in this embodiment, for the diaphragm with a larger diaphragm bending stiffness (smaller displacement under the same external force), a smaller plate spacing is adopted to obtain a larger voltage change under the same amplitude displacement, and for the diaphragm with a smaller diaphragm bending stiffness (larger displacement under the same external force), a larger plate spacing is adopted to obtain a smaller voltage change under the same amplitude displacement, so that the displacement amounts of the diaphragms with different diaphragm bending stiffnesses are different under the same external force, but the capacitance change amounts tend to be the same, improving the electrical sensitivity consistency of each diaphragm of the MEMS sensor. In summary, this embodiment can improve at least one of the mechanical sensitivity and the electrical sensitivity of each diaphragm of the MEMS sensor, and improve the sensitivity between each diaphragm of the MEMS sensor.

[0052] In addition, the present application also provides a microphone module, which includes a packaging housing and a MEMS sensor, and the MEMS sensor is disposed in the packaging housing.

[0053] The specific structure of the MEMS sensor in this microphone module refers to the above embodiment. Since this microphone module adopts all the technical solutions of the above all embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0054] In addition, the present application also provides an electronic device, and the electronic device includes the microphone module.

[0055] The specific structure of the microphone module in the electronic device refers to the above embodiments. Since this electronic device adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0056] The above description is only an exemplary embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the technical concept of the present application by using the content of the specification and drawings of the present application, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A MEMS sensor, characterized in that, The MEMS sensor includes a substrate, and at least one capacitor system disposed on the substrate, the capacitor system including a backplane and a first diaphragm and a second diaphragm disposed on both sides of the backplane; A connecting column is disposed between the first diaphragm and the second diaphragm, and under the connection of the connecting column, the connection stiffness between the first diaphragm and the second diaphragm is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm; and / or, The distance between the backplane and the first diaphragm is a first plate spacing, and the distance between the backplane and the second diaphragm is a second plate spacing, wherein the first plate spacing is negatively correlated with the diaphragm bending stiffness of the first diaphragm, and the second plate spacing is negatively correlated with the diaphragm bending stiffness of the second diaphragm.

2. The MEMS sensor according to claim 1, wherein A connecting column with a predetermined column density is disposed between the first diaphragm and the second diaphragm, and under the predetermined column density, the connection stiffness between the first diaphragm and the second diaphragm is greater than the diaphragm bending stiffness of the first diaphragm and the second diaphragm.

3. The MEMS sensor according to claim 1, characterized in that, The distance between adjacent connecting columns is greater than 50 micrometers.

4. The MEMS sensor according to claim 1, characterized in that, The total number of connecting columns between the first diaphragm and the second diaphragm is less than 1000.

5. The MEMS sensor according to claim 1, wherein Through holes are formed in the backplane, and the connecting column connects the first diaphragm and the second diaphragm through the through holes.

6. The MEMS sensor according to claim 1, wherein Micropores exist on the first diaphragm and the second diaphragm.

7. The MEMS sensor according to claim 1, characterized in that, The first diaphragm and the second diaphragm form a sealed cavity.

8. The MEMS sensor according to any one of claims 1 to 7, characterized in that, A first insulating layer is disposed between the substrate and the capacitor system; A second insulating layer is disposed between the backplane and the first diaphragm; A third insulating layer is disposed between the backplane and the second diaphragm.

9. A microphone module, characterized in that, The microphone module includes a packaging housing; and the MEMS sensor according to any one of claims 1 to 8, the MEMS sensor being disposed in the packaging housing.

10. An electronic device, characterized in that, The electronic device includes the microphone module according to claim 9.

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