Sensitive film, MEMS chip and sensor

Abstract

The invention discloses a sensitive film, an MEMS chip and a sensor, and relates to the technical field of acoustic-electric conversion equipment.The sensitive film comprises a film body and a first annular fold part, the film body comprises a first face and a second face, the first annular fold part is arranged on the second face, the first annular fold part forms a first open slot penetrating through the first face, and the first open slot penetrates through the second face; the number of the first annular fold parts is at least two, the membrane body is provided with a central area, and the at least two first annular fold parts are sequentially arranged in the central area in a surrounding mode in the first direction; any two adjacent first annular fold parts are not completely the same in shape and size, the shape and size comprise at least one of the thickness size of the first annular fold parts, the depth size and the width size of the first opening grooves, and the first direction is perpendicular to the vibration direction. The mechanical sensitivity of the MEMS microphone chip is adjusted by adjusting the shape and size of the first annular fold part, so that the mechanical sensitivity of the MEMS microphone chip is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic-electric conversion equipment, and in particular to a sensitive film, a MEMS chip and a sensor. Background Art

[0002] A MEMS microphone is a package structure consisting of a metal shell and a substrate (Printed Circuit Board, PCB for short). A MEMS microphone chip is provided on the surface of the circuit board inside the package structure, and a sound hole for receiving sound signals is provided at the position of the circuit board opposite to the MEMS microphone chip. External sound acts on the MEMS microphone chip through the sound hole to achieve the sound input effect. As the requirements for the mechanical sensitivity of MEMS microphone chips gradually increase, existing MEMS microphones are gradually unable to meet the requirements. Summary of the invention

[0003] The main purpose of the present invention is to provide a sensitive film, a MEMS chip and a sensor, aiming to solve the technical problem of how to improve the sensitivity of a MEMS microphone chip.

[0004] To achieve the above-mentioned purpose, the present invention proposes a sensitive membrane, which includes a membrane body and a first annular fold portion, wherein the membrane body includes a first surface and a second surface relatively arranged along the vibration direction of the sensitive membrane, the first annular fold portion is arranged on the second surface, and a first open groove penetrating through the first surface is formed inside the first annular fold portion, and the number of the first annular fold portions is at least two, and the membrane body is provided with a central area, and at least two of the first annular fold portions are sequentially arranged in the central area along the first direction; the shape and size of any two adjacent first annular fold portions are not exactly the same, and the shape and size include at least one of the thickness dimension of the first annular fold portion, the depth dimension of the first open groove along the vibration direction, and the width dimension of the first open groove along the first direction, and the first direction is perpendicular to the vibration direction.

[0005] In one embodiment, the thickness dimensions of any two adjacent first annular folded portions are defined as a and b, respectively, then: b≥101%a, or, 0<b≤99%a; the depth dimension and the width dimension of the first opening groove of any two adjacent first annular folded portions are the same;

[0006] or,

[0007] The depth dimensions of the first opening grooves of any two adjacent first annular folded portions are defined as c and d respectively, then: d ≥ 105% c, or 0 < d ≤ 95% c, and the thickness dimension of any two adjacent first annular folded portions and the width dimension of the first opening groove are the same;

[0008] or,

[0009] Define the width dimensions of the first opening groove of any two adjacent first annular fold parts as e and f respectively, then: f≥105%e, or, 0<f≤95%e, the thickness dimension of any two adjacent first annular fold parts and the depth dimension of the first opening groove are the same.

[0010] In one embodiment, the thickness dimensions of any two adjacent first annular folded portions are defined as a and b, respectively, and then: b ≥ 101% a, or, 0 < b ≤ 99% a; the depth dimensions of the first opening grooves of any two adjacent first annular folded portions are defined as c and d, respectively, and then: d ≥ 105% c, or, 0 < d ≤ 95% c; the width dimensions of any two adjacent first annular folded portions are the same;

[0011] or,

[0012] The thickness dimensions of any two adjacent first annular folded portions are defined as a and b, respectively, then: b≥101%a, the width dimensions of the first opening grooves of any two adjacent first annular folded portions are defined as e and f, respectively, then: f≥105%e, or, 0<f≤95%e, the depth dimensions of the first opening grooves of any two adjacent first annular folded portions are the same;

[0013] or,

[0014] The depth dimensions of the first opening grooves of any two adjacent first annular fold portions are c and d respectively, d ≥ 105% c, or 0 < d ≤ 95% c, the width dimensions of the first opening grooves of any two adjacent first annular fold portions are e and f respectively, f ≥ 105% e, or 0 < f ≤ 95% e, and the thickness dimensions of any two adjacent first annular fold portions are the same.

[0015] In one embodiment, the thickness dimensions of any two adjacent first annular fold portions are defined as a and b, respectively, and then: b ≥ 101% a, or, 0 < b ≤ 99% a; the depth dimensions of the first opening grooves of any two adjacent first annular fold portions are defined as c and d, respectively, and then: d ≥ 105% c, or, 0 < d ≤ 95% c; the width dimensions of the first opening grooves of any two adjacent first annular fold portions are defined as e and f, respectively, and then: f ≥ 105% e, or, 0 < f ≤ 95% e.

[0016] In one embodiment, the thickness dimension of any two adjacent first annular fold portions and the width dimension of the first opening groove are the same, and the depth dimension of the first opening groove away from the outer edge of the membrane body in any two adjacent first annular fold portions is defined as c, and the depth dimension of the other first opening groove is defined as d, then: d≥105%c, or, 0<d≤95%c.

[0017] In one embodiment, the depth dimension and the width dimension of the first opening groove of any two adjacent first annular fold portions are the same, and the thickness dimension of the first annular fold portion away from the outer edge of the membrane body of any two adjacent first annular fold portions is defined as a, and the thickness dimension of the other first annular fold portion is defined as b, then: b≥101%a, or, 0<b≤99%a.

[0018] In one embodiment, the thickness dimension of any two adjacent first annular fold portions and the width dimension of the first opening groove are the same, and the depth dimension of the first opening groove away from the outer edge of the membrane body in any two adjacent first annular fold portions is defined as e, and the depth dimension of the other first opening groove is defined as f, then: f≥105%e, or, 0<f≤95%e.

[0019] In one embodiment, the sensitive film also includes a second annular fold portion, which is arranged on the first surface, and a second open groove penetrating the second surface is formed inside the second annular fold portion. The number of the second annular fold portions is at least two, and at least two of the second annular fold portions are sequentially arranged in the central area along the first direction, and the shapes and sizes of any two adjacent second annular fold portions are not exactly the same.

[0020] In one embodiment, each of the first annular folds is in a circular shape, and each of the first annular folds is concentrically arranged, and any two adjacent first annular folds are arranged at an interval.

[0021] In one embodiment, the sensitive film comprises a plurality of structural layers stacked in sequence along the vibration direction, wherein the plurality of structural layers comprise an insulating layer and a conductive layer;

[0022] Alternatively, the material of the plurality of structural layers is the same.

[0023] The present invention also provides a MEMS chip, which includes the above-mentioned sensitive film.

[0024] The present invention also provides a sensor, which comprises the above-mentioned sensitive film.

[0025] The technical solution of the present invention is to provide a plurality of first annular folds on the sensitive membrane, which are sequentially surrounded by the periphery of the central area, and rely on the first annular folds to change the prestress distribution of the sensitive membrane, wherein the prestress near the central area will decrease and the prestress near the outer edge will increase with the first annular folds as the boundary, thereby improving the mechanical sensitivity of the MEMS microphone chip using the sensitive membrane by changing the distribution of the prestress; and since the shapes and sizes of any two adjacent first annular folds are not exactly the same, the mechanical sensitivity of the MEMS microphone chip can be adjusted by adjusting the shape of the first annular folds, thereby further improving the mechanical sensitivity of the MEMS microphone chip, so as to meet different mechanical sensitivity requirements and expand the application range of the sensitive membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of a top view of a sensitive film according to an embodiment of the present invention;

[0028] Figure 2 A schematic cross-sectional view of an embodiment of a sensitive film provided by the present invention;

[0029] Figure 3 A schematic diagram of the main structure of an embodiment of a sensitive film provided by the present invention;

[0030] Figure 4 A partial structural schematic diagram of an embodiment of a sensitive membrane provided by the present invention;

[0031] Figure 5 A partial structural schematic diagram of another embodiment of the sensitive membrane provided by the present invention;

[0032] Figure 6 A partial structural schematic diagram of another embodiment of the sensitive membrane provided by the present invention.

[0033] Description of Figure Numbers:

[0034] 100. Sensitive membrane; 1. Membrane body; 11. Central area; 12. First surface; 13. Second surface; 2. First annular fold portion; 21. First opening groove; 22. First side wall; 23. Second side wall; 24. Bottom wall; 3. Second annular fold portion; 31. Second opening groove.

[0035] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0038] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0039] A MEMS microphone is a package structure consisting of a metal shell and a substrate (Printed Circuit Board, PCB for short). A MEMS microphone chip is provided on the surface of the circuit board inside the package structure, and a sound hole for receiving sound signals is provided at the position of the circuit board opposite to the MEMS microphone chip. External sound acts on the MEMS microphone chip through the sound hole to achieve the sound input effect. As the requirements for the sensitivity of MEMS microphone chips gradually increase, existing MEMS microphone chips are gradually unable to meet the demand.

[0040] The inventor has found through research that the diaphragm of the currently available MEMS microphone chip generally has a smooth surface. The prestress distribution of the diaphragm with a smooth surface is relatively uniform, which leads to a low sensitivity of the MEMS microphone using the diaphragm.

[0041] The present invention provides a sensitive film, aiming to solve the technical problem of how to improve the sensitivity of a MEMS microphone chip.

[0042] See also Figures 1 to 5 As shown, in one embodiment of the present invention, the sensitive membrane 100 includes a membrane body 1 and a first annular folded portion 2, the membrane body 1 includes a first surface 12 and a second surface 13 arranged opposite to each other along the vibration direction of the sensitive membrane 100, the first annular folded portion 2 is arranged on the second surface 13, a first opening groove 21 penetrating through the first surface 12 is formed inside the first annular folded portion 2, the number of the first annular folded portions 2 is at least two, the membrane body 1 is provided with a central area 11, at least two first annular folded portions 2 are sequentially arranged in the central area 11 along the first direction; the shape and size of any two adjacent first annular folded portions 2 are not completely the same, and the shape and size include at least one of the thickness dimension of the first annular folded portion 2, the depth dimension of the first opening groove 21 along the vibration direction, and the width dimension of the first opening groove 21 along the first direction, and the first direction is perpendicular to the vibration direction.

[0043] The sensitive film 100 can be applied to a microphone or a sensor, such as the sensitive film 100 in a microphone or the sensitive film 100 of other piezoresistive, piezoelectric, or optical sensors. The following description takes the sensitive film 100 as the sensitive film 100 of a MEMS microphone chip as an example.

[0044] The technical solution of the present invention adopts a method of setting a plurality of first annular folds 2 on the sensitive film 100, which are sequentially surrounded by the periphery of the central area 11, and changing the prestress distribution of the sensitive film 100 by means of the first annular folds 2, wherein the prestress near the central area 11 will decrease with the first annular folds 2 as the boundary, and the prestress near the outer edge will increase, thereby improving the mechanical sensitivity of the MEMS microphone chip using the sensitive film 100 by changing the distribution of the prestress; and since a plurality of first annular folds 2 are added to the sensitive film 100, the effective capacitance area of ​​the MEMS microphone is also increased. The effective capacitance area of ​​the MEMS microphone refers to the effective capacitance area formed between the diaphragm and the back plate in the capacitive MEMS microphone.

[0045] The inventors have discovered that if the shape and size of each first annular fold portion 2 are the same, that is, regular first annular fold portions 2 are distributed on the sensitive film 100, due to the limited space on the diaphragm, the number of first annular fold portions 2 set is also limited. Therefore, the solution of improving the mechanical sensitivity of the MEMS microphone chip by setting a plurality of first annular fold portions 2 on the diaphragm has limitations, that is, it is difficult to improve the mechanical sensitivity of the MEMS microphone chip by adding a plurality of first annular fold portions 2 after a certain degree. However, as the requirements for the mechanical sensitivity of the MEMS microphone chip gradually increase, it is necessary to make further breakthroughs on the basis of setting the first annular fold portions 2 in order to continue to meet the requirements of mechanical sensitivity.

[0046] This embodiment also adjusts the shape of the first annular fold portion 2 to adjust the mechanical sensitivity of the MEMS microphone chip by setting the shape and size of any two adjacent first annular fold portions 2 to be not completely the same, such as the thickness of the first annular fold portion 2 is not completely the same, or the depth of the first opening groove 21 along the vibration direction is not completely the same, or the width of the first opening groove 21 along the first direction is not completely the same. The mechanical sensitivity of the MEMS microphone chip is further improved to meet different mechanical sensitivity requirements and expand the application range of the sensitive membrane 100. It should be noted that the membrane body 1 and the first annular fold portion 2 are an integrally formed part, wherein the first annular fold portion 2 can be formed by an etching process. It should also be noted that the outer contour of the first annular fold portion 2 can be a rectangle or a circular ring, and no specific limitation is made here. It should also be noted that the vibration direction is Figure 3 The up and down directions shown, the first direction is Figure 3 Left and right directions shown.

[0047] According to an embodiment of the present invention, the distance between any two adjacent first annular fold portions 2 is not completely the same. By adjusting the distance between any two adjacent first annular fold portions 2, the mechanical sensitivity of the MEMS microphone chip can also be adjusted, thereby further improving the mechanical sensitivity of the MEMS microphone chip.

[0048] See also Figure 3 and Figure 4As shown, in one embodiment, the thickness dimensions of any two adjacent first annular fold portions 2 are defined as a and b respectively, then: b≥101%a, or, 0<b≤99%a; the depth dimension and width dimension of the first opening groove 21 of any two adjacent first annular fold portions 2 are the same; there is a difference in the thickness dimension of any two adjacent first annular fold portions 2, while the depth dimension and width dimension of the first opening groove 21 are the same, and the mechanical sensitivity of the MEMS microphone chip is adjusted by adjusting the thickness dimension of any two adjacent first annular fold portions 2, and then the thickness dimension of the first annular fold portion 2 can be changed according to demand to improve the mechanical sensitivity of the MEMS microphone chip.

[0049] In one embodiment, the depth dimensions of the first opening groove 21 of any two adjacent first annular fold portions 2 are defined as c and d respectively, then: d≥105%c, or, 0<d≤95%c, the thickness dimension of any two adjacent first annular fold portions 2 and the width dimension of the first opening groove 21 are the same; there is a difference in the depth dimension of the first opening groove 21 of any two adjacent first annular fold portions 2, while the thickness dimension of the first annular fold portion 2 and the width dimension of the first opening groove 21 are the same, and the mechanical sensitivity of the MEMS microphone chip is adjusted by adjusting the depth dimension of the first opening groove 21 of any two adjacent first annular fold portions 2, so as to achieve the adjustment of the mechanical sensitivity of the MEMS microphone chip, and then the depth dimension of the first opening groove 21 of the first annular fold portion 2 can be changed according to demand to improve the mechanical sensitivity of the MEMS microphone chip.

[0050] In one embodiment, the width dimensions of the first opening groove 21 of any two adjacent first annular fold parts 2 are defined as e and f respectively, then: f≥105%e, or, 0<f≤95%e, the thickness dimension of any two adjacent first annular fold parts 2 and the depth dimension of the first opening groove 21 are the same. There is a difference in the width dimension of the first opening groove 21 of any two adjacent first annular fold parts 2, while the thickness dimension of the first annular fold part 2 and the depth dimension of the first opening groove 21 of the first annular fold part 2 are the same. By adjusting the depth dimension of the first opening groove 21 of any two adjacent first annular fold parts 2, the mechanical sensitivity of the MEMS microphone chip can be adjusted, and then the depth dimension of the first opening groove 21 of the first annular fold part 2 can be changed according to demand to improve the mechanical sensitivity of the MEMS microphone chip.

[0051] See also Figure 3 and Figure 4As shown, in one embodiment, the thickness dimensions of any two adjacent first annular fold parts 2 are defined as a and b, respectively, then: b ≥ 101% a, or, 0 < b ≤ 99% a, the depth dimensions of the first opening groove 21 of any two adjacent first annular fold parts 2 are defined as c and d, respectively, then: d ≥ 105% c, or, 0 < d ≤ 95% c, the width dimensions of any two adjacent first annular fold parts 2 are the same; there are differences in the thickness dimensions of any two adjacent first annular fold parts 2, and the first opening grooves of any two adjacent first annular fold parts 2 There are differences in the depth dimensions of the first opening grooves 21, while the width dimensions of the first opening grooves 21 of any two adjacent first annular fold portions 2 are the same. By adjusting the thickness dimensions of any two adjacent first annular fold portions 2 and the depth dimensions of the first opening grooves 21, not only the mechanical sensitivity of the MEMS microphone chip can be adjusted, but also the adjustment range of the mechanical sensitivity of the MEMS microphone chip is expanded. Furthermore, the thickness dimensions of the first annular fold portions 2 and the depth dimensions of the first opening grooves 21 can be changed according to needs to improve the mechanical sensitivity of the MEMS microphone chip.

[0052] In one embodiment, the thickness dimensions of any two adjacent first annular fold portions 2 are defined as a and b, respectively, and then: b≥101%a; the width dimensions of the first opening groove 21 of any two adjacent first annular fold portions 2 are defined as e and f, respectively, and then: f≥105%e, or, 0<f≤95%e; the depth dimensions of the first opening groove 21 of any two adjacent first annular fold portions 2 are the same; there is a difference in the thickness dimension of any two adjacent first annular fold portions 2, and there is a difference in the width dimension of the first opening groove 21 of any two adjacent first annular fold portions 2, while the depth dimension of the first opening groove 21 of any two adjacent first annular fold portions 2 is the same; by adjusting the thickness dimension of any two adjacent first annular fold portions 2 and the width dimension of the first opening groove 21, not only the mechanical sensitivity of the MEMS microphone chip is adjusted, but also the adjustment range of the mechanical sensitivity of the MEMS microphone chip is expanded, and then the thickness dimension of the first annular fold portion 2 and the width dimension of the first opening groove 21 can be changed according to demand to improve the mechanical sensitivity of the MEMS microphone chip.

[0053] In one embodiment, the depth dimensions of the first opening grooves 21 of any two adjacent first annular folds 2 are c and d, respectively, d≥105%c, or 0<d≤95%c, the width dimensions of the first opening grooves 21 of any two adjacent first annular folds 2 are e and f, respectively, f≥105%e, or 0<f≤95%e, and the thickness dimensions of any two adjacent first annular folds 2 are the same. The depth dimensions of the first opening grooves 21 of any two adjacent first annular folds 2 are different, and the width dimensions of the first opening grooves 21 of any two adjacent first annular folds 2 are different, while the thickness dimensions of any two adjacent first annular folds 2 are the same. By adjusting the depth dimensions and width dimensions of the first opening grooves 21 of any two adjacent first annular folds 2, not only the mechanical sensitivity of the MEMS microphone chip is adjusted, but also the adjustment range of the mechanical sensitivity of the MEMS microphone chip is expanded, and then the depth dimensions and width dimensions of the first opening grooves 21 of the first annular folds 2 can be changed according to needs to improve the mechanical sensitivity of the MEMS microphone chip.

[0054] See also Figure 3 and Figure 4 As shown, in one embodiment, the thickness dimensions of any two adjacent first annular fold portions 2 are defined as a and b, respectively, and then: b ≥ 101% a, or, 0 < b ≤ 99% a, the depth dimensions of the first opening groove 21 of any two adjacent first annular fold portions 2 are defined as c and d, respectively, and then: d ≥ 105% c, or, 0 < d ≤ 95% c, the width dimensions of the first opening groove 21 of any two adjacent first annular fold portions 2 are defined as e and f, respectively, and then: f ≥ 105% e, or, 0 < f ≤ 95% e. There are differences in the thickness dimension of any two adjacent first annular fold portions 2, and the depth dimension and width dimension of the first opening groove 21. By adjusting the thickness dimension of any two adjacent first annular fold portions 2, and the depth dimension and width dimension of the first opening groove 21, not only the mechanical sensitivity of the MEMS microphone chip can be adjusted, but also the adjustment range of the mechanical sensitivity of the MEMS microphone chip is further expanded. Then, the thickness dimension of the first annular fold portion 2, and the depth dimension and width dimension of the first opening groove 21 can be changed according to needs to improve the mechanical sensitivity of the MEMS microphone chip.

[0055] See also Figure 2As shown, in one embodiment, the thickness dimension of any two adjacent first annular folds 2 and the width dimension of the first opening groove 21 are the same, and the depth dimension of the first opening groove 21 away from the outer edge of the membrane body 1 in any two adjacent first annular folds 2 is defined as c, and the depth dimension of the other first opening groove 21 is defined as d, then: d ≥ 105% c, or, 0 < d ≤ 95% c. Among them, the thickness dimension of any two adjacent first annular folds 2 and the width dimension of the first opening groove 21 are the same, and the depth dimension of the first opening groove 21 of each first annular fold 2 gradually increases or decreases from the central area 11 to the direction away from the central area 11, thereby realizing the adjustment of the mechanical sensitivity of the MEMS microphone chip, and then the depth of the first opening groove 21 of any first annular fold 2 can be changed according to demand to improve the mechanical sensitivity of the MEMS microphone chip.

[0056] In one embodiment, the depth dimension and width dimension of the first opening groove 21 of any two adjacent first annular fold parts 2 are the same, and the thickness dimension of the first annular fold part 2 away from the outer edge of the membrane body 1 of any two adjacent first annular fold parts 2 is defined as a, and the thickness dimension of the other first annular fold part 2 is defined as b, then: b ≥ 101% a, or, 0 < b ≤ 99% a. Among them, the depth dimension and width dimension of the first opening groove 21 of any two adjacent first annular fold parts 2 are the same, and the thickness dimension of each first annular fold part 2 gradually increases or decreases from the central area 11 to the direction away from the central area 11, thereby realizing the adjustment of the mechanical sensitivity of the MEMS microphone chip, and then the thickness dimension of any first annular fold part 2 can be changed according to demand to improve the mechanical sensitivity of the MEMS microphone chip.

[0057] In one embodiment, the thickness dimension of any two adjacent first annular folds 2 and the width dimension of the first opening groove 21 are the same. The depth dimension of the first opening groove 21 away from the outer edge of the membrane body 1 in any two adjacent first annular folds 2 is defined as e, and the depth dimension of the other first opening groove 21 is defined as f, then: f≥105%e, or, 0<f≤95%e. Among them, the thickness dimension of any two adjacent first annular folds 2 and the width dimension of the first opening groove 21 are the same, and the depth dimension of the first opening groove 21 of each first annular fold 2 gradually increases or decreases from the central area 11 to the direction away from the central area 11, thereby adjusting the mechanical sensitivity of the MEMS microphone chip, and then the depth dimension of the first opening groove 21 of any first annular fold 2 can be changed according to demand to improve the mechanical sensitivity of the MEMS microphone chip.

[0058] See also Figure 5As shown, in one embodiment, the sensitive film 100 further includes a second annular folded portion 3, which is arranged on the first surface 12, and a second opening groove 31 penetrating the second surface 13 is formed inside the second annular folded portion 3. The number of the second annular folded portions 3 is at least two, and at least two second annular folded portions 3 are arranged in sequence in the central area 11 along the first direction, and the shapes and sizes of any two adjacent second annular folded portions 3 are not completely the same. By setting the second annular folded portion 3, the prestress distribution on the sensitive film 100 is further changed, and the positions of the first annular folded portion 2 and the second annular folded portion 3 are adjusted to improve the mechanical sensitivity of the MEMS microphone chip; on this basis, the shapes and sizes of any two adjacent second annular folded portions 3 are not completely the same, so as to further adjust the mechanical sensitivity of the MEMS microphone chip, so as to meet the requirements of different sensitivities and expand the application range of the sensitive film 100. It should be noted that the shape and size of the second annular folded portion 3 include at least one of the thickness of the second annular folded portion 3, the depth of the second opening groove 31, and the width of the second opening groove 31.

[0059] See also Figure 6 As shown, according to an embodiment of the present invention, each first annular fold portion 2 includes a first side wall 22, a second side wall 23 and a bottom wall 24 connecting the first side wall 22 and the second side wall 23, and the thickness dimension includes a first thickness dimension, a second thickness dimension and a third thickness dimension. The dimension of the first side wall 22 in the first direction is the first thickness dimension, the dimension of the second side wall 23 in the first direction is the second thickness dimension, and the dimension of the bottom wall 24 in the vibration direction is the third thickness dimension. The first thickness dimension, the second thickness dimension and the third thickness dimension of each annular recess are the same, or the first thickness dimension, the second thickness dimension and the third thickness dimension of each annular recess are not completely the same. By adjusting the first thickness dimension, the second thickness dimension and the third thickness dimension respectively, the mechanical sensitivity of the MEMS microphone chip is further adjusted to increase the mechanical sensitivity of the MEMS microphone chip. Among them, the first thickness dimension is Figure 6 a1 shown, the second thickness dimension is Figure 6 a2 shown, the third thickness dimension is Figure 6 a3 shown.

[0060] In one embodiment, each first annular fold portion 2 is in the shape of a ring, and each first annular fold portion 2 is concentrically arranged, and any two adjacent first annular fold portions 2 are arranged at intervals. Each first annular fold portion 2 is in the shape of a ring, which avoids the occurrence of stress concentration caused by a special-shaped structure.

[0061] In one embodiment, the sensitive film 100 has multiple structural layers stacked in sequence along the vibration direction, and the multiple structural layers include an insulating layer and a conductive layer; the material of the conductive layer can be a semiconductor material or a conductor material, and the material of the insulating layer can be an oxide, a nitride or other insulating material.

[0062] In one embodiment, the multiple structural layers are made of the same material, which is convenient for production and processing.

[0063] The present invention also proposes a MEMS chip, the MEMS chip includes the above-mentioned sensitive film, the sensitive film is a diaphragm, and is used to receive sound pressure signals. Since the MEMS chip adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here. It should be noted that the sensitive film can also be applied to CMOS chips.

[0064] The present invention also provides a sensor, which includes the above-mentioned sensitive film 100. Since the sensor adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here. Among them, the sensor can be a pressure sensor or a sound sensor.

[0065] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A sensitive film, characterized in that: The sensitive membrane includes a membrane body and a first annular fold portion, the membrane body includes a first surface and a second surface arranged opposite to each other along the vibration direction of the sensitive membrane, the first annular fold portion is arranged on the second surface, a first open groove penetrating the first surface is formed inside the first annular fold portion, the number of the first annular fold portions is at least two, the membrane body is provided with a central area, at least two of the first annular fold portions are sequentially arranged in the central area along the first direction; the shape and size of any two adjacent first annular fold portions are not exactly the same, the shape and size include the thickness dimension of the first annular fold portion, the depth dimension of the first opening groove along the vibration direction and at least one of the width dimension of the first opening groove along the first direction, and the first direction is perpendicular to the vibration direction.

2. The sensitive film according to claim 1, characterized in that: The thickness dimensions of any two adjacent first annular fold parts are defined as a and b respectively, then: b≥101%a, or, 0<b≤99%a; the depth dimension and the width dimension of the first opening groove of any two adjacent first annular fold parts are the same; or, The depth dimensions of the first opening grooves of any two adjacent first annular folded portions are defined as c and d respectively, then: d ≥ 105% c, or 0 < d ≤ 95% c, and the thickness dimension of any two adjacent first annular folded portions and the width dimension of the first opening groove are the same; or, Define the width dimensions of the first opening groove of any two adjacent first annular fold parts as e and f respectively, then: f≥105%e, or, 0<f≤95%e, the thickness dimension of any two adjacent first annular fold parts and the depth dimension of the first opening groove are the same.

3. The sensitive film according to claim 1, characterized in that: The thickness dimensions of any two adjacent first annular fold parts are defined as a and b, respectively, then: b ≥ 101% a, or, 0 < b ≤ 99% a; the depth dimensions of the first opening grooves of any two adjacent first annular fold parts are defined as c and d, respectively, then: d ≥ 105% c, or, 0 < d ≤ 95% c; the width dimensions of any two adjacent first annular fold parts are the same; or, The thickness dimensions of any two adjacent first annular folded portions are defined as a and b, respectively, then: b≥101%a, the width dimensions of the first opening grooves of any two adjacent first annular folded portions are defined as e and f, respectively, then: f≥105%e, or, 0<f≤95%e, the depth dimensions of the first opening grooves of any two adjacent first annular folded portions are the same; or, The depth dimensions of the first opening grooves of any two adjacent first annular fold portions are c and d respectively, d ≥ 105% c, or 0 < d ≤ 95% c, the width dimensions of the first opening grooves of any two adjacent first annular fold portions are e and f respectively, f ≥ 105% e, or 0 < f ≤ 95% e, and the thickness dimensions of any two adjacent first annular fold portions are the same.

4. The sensitive film according to claim 1, characterized in that: Define the thickness dimensions of any two adjacent first annular fold portions as a and b, respectively, then: b ≥ 101% a, or, 0 < b ≤ 99% a, define the depth dimensions of the first opening groove of any two adjacent first annular fold portions as c and d, respectively, then: d ≥ 105% c, or, 0 < d ≤ 95% c, define the width dimensions of the first opening groove of any two adjacent first annular fold portions as e and f, respectively, then: f ≥ 105% e, or, 0 < f ≤ 95% e.

5. The sensitive film according to claim 1, characterized in that: The thickness dimension of any two adjacent first annular fold portions and the width dimension of the first opening groove are the same. The depth dimension of the first opening groove away from the outer edge of the membrane body in any two adjacent first annular fold portions is defined as c, and the depth dimension of the other first opening groove is defined as d. Then: d≥105%c, or, 0<d≤95%c.

6. The sensitive film according to claim 1, characterized in that: The depth dimension and the width dimension of the first opening groove of any two adjacent first annular fold parts are the same. The thickness dimension of the first annular fold part away from the outer edge of the membrane body among any two adjacent first annular fold parts is defined as a, and the thickness dimension of the other first annular fold part is defined as b, then: b≥101%a, or, 0<b≤99%a.

7. The sensitive film according to claim 1, characterized in that: The thickness dimension of any two adjacent first annular folds and the width dimension of the first opening groove are the same. The depth dimension of the first opening groove away from the outer edge of the membrane body in any two adjacent first annular folds is defined as e, and the depth dimension of the other first opening groove is defined as f. Then: f≥105%e, or, 0<f≤95%e.

8. The sensitive film according to any one of claims 1 to 7, characterized in that: The sensitive film also includes a second annular fold portion, which is arranged on the first surface. A second open groove that penetrates the second surface is formed inside the second annular fold portion. The number of the second annular fold portions is at least two, and at least two of the second annular fold portions are sequentially arranged in the central area along the first direction. The shapes and sizes of any two adjacent second annular fold portions are not exactly the same.

9. The sensitive film according to any one of claims 1 to 7, characterized in that: Each of the first annular fold portions is in a circular shape, and each of the first annular fold portions is concentrically arranged, and any two adjacent first annular fold portions are arranged at an interval.

10. The sensitive film according to any one of claims 1 to 7, characterized in that: The sensitive film has a plurality of structural layers stacked in sequence along the vibration direction, wherein the plurality of structural layers include an insulating layer and a conductive layer; Alternatively, the material of the plurality of structural layers is the same.

11. A MEMS chip, characterized in that: The MEMS chip comprises the sensitive film according to any one of claims 1 to 10.

12. A sensor, characterized in that: The sensor comprises the sensitive film according to any one of claims 1 to 10.

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