CN110775937B

CN110775937B - MEMS diaphragm and MEMS sensor chip

Info

Publication number: CN110775937B
Application number: CN201911401486.9A
Authority: CN
Inventors: 何宪龙
Original assignee: Gettop Acoustic Co Ltd
Current assignee: Gettop Acoustic Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-05-08
Anticipated expiration: 2039-12-31
Also published as: CN110775937A

Abstract

The invention provides an MEMS diaphragm and an MEMS sensor chip, wherein the MEMS diaphragm comprises a sensing part and a peripheral part surrounding the periphery of the sensing part, a plurality of outer grooves and a plurality of inner grooves are arranged between the peripheral part and the sensing part, the outer grooves are annularly arranged on the inner edge of the peripheral part, the tail ends of the outer grooves extend towards the inner side, the inner grooves are annularly arranged on the outer edge of the sensing part, the tail ends of the inner grooves extend towards the inner side, and the part of each inner groove corresponding to the tail ends of two adjacent outer grooves is inwards sunken so as to form an inner section.

Description

MEMS diaphragm and MEMS sensor chip

Technical Field

The invention relates to the technical field of Micro-Electro-Mechanical systems (MEMS), in particular to an MEMS membrane and an MEMS sensor chip.

Background

The mems sensor has been widely used in various acoustic receivers or force sensors, and has characteristics of small size, low power consumption, high sensitivity, etc., which are the design targets, and it can be known from the theoretical simulation result that the influence of residual stress has a great influence on the mechanical sensitivity of the vibrating membrane in the acoustic sensor.

The mems device includes a capacitive sensor structure, which is generally a sensing film coupled with a back electrode to form two parallel plate capacitor structures for sensing vibration or pressure change. The material properties of the sensing film determine the device sensitivity performance, but the thermal residual stress generated during the semiconductor processing process cannot be avoided. The existing process technology still cannot precisely control the film stress, and thus the sensitivity of the micro-electromechanical device is low or the sensitivity varies.

Therefore, how to provide a sensing film with good stress releasing effect and high mechanical sensitivity is a problem that needs to be solved in the industry.

Disclosure of Invention

In view of this, the present invention provides a MEMS membrane with high mechanical sensitivity.

The invention also provides an MEMS sensor chip applying the MEMS membrane.

The invention provides an MEMS (micro-electromechanical system) membrane, which comprises a sensing part and a peripheral part surrounding the periphery of the sensing part, wherein a plurality of outer grooves and a plurality of inner grooves are arranged between the peripheral part and the sensing part, the outer grooves are annularly arranged at the inner edge of the peripheral part, the tail ends of the outer grooves extend towards the inner side, the inner grooves are annularly arranged at the outer edge of the sensing part, the tail ends of the inner grooves extend towards the inner side, and the part of each inner groove, corresponding to the tail ends of two adjacent outer grooves, is inwards sunken so as to form an inner concave section.

Preferably, each of the outer grooves includes at least one first arc segment, each of the inner grooves includes at least one second arc segment, and the first arc segment and the second arc segment are concentric.

Preferably, each inner groove further comprises at least one inclined section, and the inclined section extends obliquely towards the inner side of the sensing part relative to the second circular arc section.

Preferably, the tail end of the outer groove is provided with a first bending part, the first bending part comprises an arc-shaped section, a straight section or a combination of the arc-shaped section and the straight section, and the first bending part extends into the recess of the corresponding inner groove respectively; the tail end of the inner groove is provided with a second bending part, and the second bending part comprises an arc-shaped section, a straight-line section or a combination of the arc-shaped section and the straight-line section.

Preferably, the end of the first bending part is an arc-shaped end; or the tail end of the second bending part is an arc-shaped tail end.

Preferably, two adjacent outer troughs form first linking arm between, two adjacent inner troughs form the second linking arm between, a plurality of outer troughs with form annular linking arm between a plurality of inner troughs, first linking arm is followed the outside edge of annular linking arm is outwards extended and with peripheral portion is connected, the second linking arm is followed the inside edge of annular linking arm is inwards extended and with sensing portion is connected, first linking arm with the second linking arm is in stagger each other in annular linking arm's circumference.

Preferably, said annular connecting arms have a uniform radial width; or the radial width of the part of the annular connecting arm adjacent to the second connecting arm is larger than that of other parts of the annular connecting arm.

Preferably, the number of the outer grooves is less than or equal to 6, and when the MEMS membrane is subjected to an external pressure, the sensing portion is substantially planar and moves relative to the peripheral portion in a direction perpendicular to the membrane.

Preferably, each outer groove corresponds to a pair of adjacent inner grooves in the radial direction of the diaphragm, and the second connecting arm between the pair of adjacent inner grooves is opposite to or offset from the circumferential middle part of the corresponding outer groove.

Preferably, the minimum circumferential width of the first connecting arm is greater than the minimum circumferential width of the second connecting arm.

The invention provides an MEMS sensor chip which comprises the MEMS diaphragm.

In summary, the present invention provides a MEMS diaphragm, in which a plurality of outer grooves and a plurality of inner grooves are disposed between a sensing portion and an outer peripheral portion, ends of the outer grooves extend toward an inner side, and ends of the inner grooves extend toward the inner side. An annular connecting arm is formed between the outer grooves and the inner grooves, a first connecting arm is formed between every two adjacent outer grooves, and a second connecting arm is formed between every two adjacent inner grooves. A plurality of water jackets are the annular and arrange the inward flange in peripheral portion, and a plurality of inside grooves are the annular and arrange the outward flange in sensing portion, and the position that each inside groove corresponds two adjacent water jacket ends is inside sunken, so design can increase the effective area of the sensing portion of diaphragm, and the increase capacitance value has better acoustic sensing performance.

In some embodiments, the number of the outer grooves is less than or equal to 6, and when the MEMS diaphragm is subjected to an external pressure, such as a sound pressure, the sensing portion can perform a piston-type motion with respect to the peripheral portion, that is, the sensing portion is substantially planar during a motion, so as to increase a change rate of a capacitance formed between the diaphragm and the back plate during the motion, thereby improving a sensitivity of the MEMS sensor chip.

When the MEMS diaphragm is under the action of larger pressure, the sensing part is basically in a plane shape and moves relative to the peripheral part along the direction vertical to the diaphragm, so that the stress is released in time, external mechanical force such as larger pressure can be released, and the diaphragm is not resisted by the external mechanical force, thereby improving the mechanical reliability of the MEMS diaphragm and the MEMS sensor chip.

In some embodiments, the first connecting arm and the second connecting arm are staggered in the circumferential direction, and the arc-shaped design of the outer groove end and the inner groove end can reduce stress concentration, so that the mechanical sensitivity of the sensing part is improved due to the outer groove end and the inner groove end which extend in a bent shape, and the reliability of the diaphragm is improved.

In some embodiments, the annular connecting arm and the second connecting arm drive the sensing portion to move, and the annular connecting arm and the second connecting arm are located far away from the clamped point and are not affected by the position of the clamped point due to semiconductor process variation, so that the motion of the sensing portion is insensitive to the position variation of the clamped point, and the sensing stability and reliability of the MEMS membrane can be improved.

Drawings

FIG. 1 is a schematic diagram of the MEMS diaphragm of the present invention as a structural design E-1.

FIG. 2 is a schematic diagram of the MEMS diaphragm of the present invention as structural design E-2.

FIG. 3 is a schematic diagram of the MEMS diaphragm of FIG. 2 showing planar vertical motion.

FIG. 4 is a schematic diagram of MEMS membrane of the present invention as structural design E-3.

FIG. 5 is a schematic diagram of the MEMS diaphragm of FIG. 4 showing planar vertical motion.

Fig. 6 is an enlarged view of the recessed area of the inner tank of fig. 4.

Fig. 7 is an enlarged view of the circular arc type end.

Detailed Description

Before the embodiments are described in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in other forms of implementation. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having," and the like, herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. In particular, when "a certain component" is described, the present invention is not limited to the number of the component being one, and may include a plurality of components.

Fig. 1 is a schematic structural diagram of a MEMS diaphragm according to an embodiment of the present invention. The MEMS membrane 10 is used in a micro-electromechanical device, for example, in a micro-electromechanical sensor, a micro-electromechanical condenser microphone. The MEMS membrane 10 includes a sensing portion 12 and a peripheral portion 14, wherein the sensing portion 12 is located on an inner side of the MEMS membrane 10, and the peripheral portion 14 is located on an outer side of the MEMS membrane 10 and surrounds the sensing portion 12. The sensing portion 12 is used for sensing an external pressure, for example, sensing a sound pressure, and when the micro-electromechanical condenser microphone is applied, the sensing portion 12 moves relative to the backplate under the action of the sound pressure, so that a capacitance between the sensing portion and the backplate changes to generate a corresponding electrical signal. The peripheral portion 14 is used to connect and support the sensing portion 12.

The region between the sensing portion 12 and the peripheral portion 14 is provided with a plurality of outer grooves 16 and a plurality of inner grooves 18, the plurality of outer grooves 16 are annular and are arranged at the inner edge of the peripheral portion 14 at intervals, the plurality of outer grooves 16 jointly define an outer circle, the plurality of inner grooves 18 are annular and are arranged at the outer edge of the sensing portion 12 at intervals, and the plurality of inner grooves 18 jointly define an inner circle. In this embodiment, the outer circle and the inner circle are concentric. Annular connecting arms 20 are formed between the outer grooves 16 and the inner grooves 18, and the peripheral portion 14 is connected to the sensing portion 12 through the annular connecting arms 20. The annular connecting arm 20 separates the peripheral portion 14 from the sensing portion 12, and prevents the force generated by elastic deformation from being transmitted to the sensing region when the peripheral portion 14 is deformed, so as to improve the stability of the sensing portion 12 and the stability of the linear output of the MEMS membrane 10. The width of the annular connecting arm 20 may be determined according to actual design requirements for distributing stress and reducing stress concentration on the MEMS membrane 10.

In some embodiments, such as the MEMS diaphragm structural design E-1 shown in FIG. 1, the annular connecting arms 20 have a uniform radial width, i.e., the inner and outer edges of the outer slots 16 each extend in an outer circumferential direction and the inner and outer edges of the inner slots 18 each extend in an inner circumferential direction.

In other embodiments, such as the MEMS diaphragm structure design E-2 of FIGS. 2-3 and the MEMS diaphragm structure design E-3 of FIGS. 4-6, the annular connecting arm 20 may also have a varying radial width, for example, increasing its radial width in areas of greater stress to increase its stiffness, for example, the annular connecting arm 20 may have a greater width near the ends of the inner and/or

outer grooves

18, 16 than at the ends. In the illustrated embodiment, the annular connecting arms 20 have a greater radial width at the ends proximal to the inner groove 18 than at the ends distal thereto.

In this embodiment, the sensing portion 12, the annular connecting arm 20 and the peripheral portion 14 can be integrally formed. The MEMS membrane 10 may be made of carbon-based polymer, silicon nitride, polysilicon, silicon dioxide, silicon carbide, arsenide, carbon, and metals such as germanium, gallium, titanium, gold, iron, copper, chromium, tungsten, aluminum, platinum, nickel, tantalum, or alloys thereof. The MEMS membrane 10 may be square, circular, or other shapes, and in this embodiment, a circle is illustrated. That is, the peripheral portion 14 is also circular.

In some embodiments, such as design E-1, design E-2, and design E-3, the plurality of outer slots 16 and the plurality of inner slots 18 are of symmetrical design with respect to each other. For example, the plurality of outer grooves 16 and the plurality of inner grooves 18 are both symmetrical with respect to at least one radial direction of the sensing part 12, that is, the diaphragm as a whole is symmetrical with respect to at least one radial direction of the sensing part 12.

In other embodiments, outer slots 16 and inner slots 18 are asymmetric with respect to each other, i.e., the membrane is asymmetric as a whole with respect to any diameter of sensing portion 12.

Through simulation calculation and analysis, the diaphragm of the embodiment of the invention has the advantages of higher sensitivity, better mechanical reliability and the like compared with the prior art. However, a comparative analysis of the above examples shows that the sensitivity of the diaphragm is higher when the inner groove 18 and the outer groove 16 are designed symmetrically under the same conditions; when inner groove 18 and outer groove 16 are asymmetrically designed, the diaphragm has better rigidity, mechanical strength and mechanical reliability.

It should be noted that the outer side and the inner side are relative to the central portion of the entire MEMS membrane 10, the outer side is a direction away from the central portion of the membrane, and the inner side is a direction toward the central portion of the membrane. In this embodiment, the outer slots 16 together define an outer circle, the inner slots 18 together define an inner circle, the outer circle and the inner circle are concentric, and the peripheral portion 14 and the sensing portion 12 are both circular, so that the center of the circle is also the center of the peripheral portion 14 and the sensing portion 12, or the center of the MEMS membrane 10, and the centers of the circles are the same. The center of the MEMS membrane 10 can also be understood as the center of the circle.

In some other embodiments, the shape of the peripheral portion 14 and the sensing portion 12 may also be non-circular, such as square, etc., the plurality of outer slots 16 and the plurality of inner slots 18 form a square, respectively, and the center of the peripheral portion 14 and the sensing portion 12 may or may not be concentric with the center of the square formed by the plurality of outer slots 16 and the plurality of inner slots 18.

The number of the outer grooves 16 and the inner grooves 18 can be set to be plural according to specific design requirements and practical use conditions.

The number of outer slots 16 and inner slots 18 may be the same or different. Preferably, both are equal in number.

The number of the outer grooves 16 may be odd or even, and the number of the inner grooves 18 may be odd or even. In this embodiment, both are even numbers. Further, the number of the outer grooves 16 is preferably six or less. Still further, four are preferable. It will be understood that for a diaphragm of equal size, the smaller the number of outer slots 16 means that the sensing portion is less constrained, the longer the length of each slot, and the longer the length of the annular connecting arm between the ends of adjacent inner and outer slots, the closer the sensing portion moves when the diaphragm is subjected to external forces, i.e. the straight-up and straight-down motion mode. In some embodiments of the invention, the number of outer slots 16 is equal to or less than six, and may be, for example, six, five, four, three, or two, and the number of inner slots 18 is equal to or less than six, and may be, for example, six, five, four, three, or two.

In the embodiment shown in fig. 1-6, the number of outer slots 16 and inner slots 18 is set to four each.

The four outer grooves 16 are evenly spaced in the circumferential direction, and each outer groove 16 is uniform in shape and structure. The four inner grooves 18 are evenly spaced circumferentially and each inner groove 18 is identical in shape and configuration. The shape and structure of only one outer tank 16 and one inner tank 18 will be described below.

The two ends of each outer groove 16 are provided with first bent parts 22, the first bent parts 22 extend towards the inner side of the membrane, and the part of each inner groove 18 corresponding to the ends of two adjacent outer grooves 16, namely the first bent parts 22, is inwards recessed to form an inner concave section 18 b. The design can increase the effective area of the sensing part 12 of the diaphragm, increase the capacitance between the diaphragm and the back plate and have better acoustic sensing performance.

Preferably, the first bent portion 22 may include an arc-shaped segment, a straight segment or a combination of the arc-shaped segment and the straight segment. That is, the end of the outer groove 16 may extend inward in a curved shape, may extend inward in a straight shape, may extend inward in a curved shape first and then in a straight shape, or may extend inward in a straight shape first and then in a curved shape.

Referring to fig. 7, in the embodiment shown, the two ends of each outer slot 16 are provided with first bending portions 22. In order to reduce the stress concentration, the end of the first bent portion 22 may be a circular arc-shaped end a.

The second bend 24 may also comprise a curved segment, a straight segment, or a combination of curved and straight segments. That is, the end of the inner tank 18 may extend inward in a curved shape, may extend inward in a straight shape, may extend inward in a curved shape first and then in a straight shape, or may extend inward in a straight shape first and then in a curved shape.

In the illustrated embodiment, the ends of each inner groove 18 are provided with second bends 24. In order to reduce stress concentration, the end of the second bent portion 24 may be a circular arc-shaped end a.

In the embodiment shown in fig. 1-3, i.e. designs E-1 and E-2, the first bent portion 22 at the end of the outer slot 16 extends toward the inner side, and the first bent portion 22 is a combination of an arc-shaped section and a straight-line section, i.e. the first bent portion 22 is first curved and smoothly transited and then linearly extends toward the inner side. The second bent portion 24 at the end of the inner groove 18 extends towards the inner side, and the second bent portion 24 is a combination of an arc-shaped section and a straight-line section, i.e. the second bent portion 24 is first curved and smoothly transited and then linearly extends towards the inner side.

In the embodiment shown in fig. 4-6, i.e. design E-3, the first bending portion 22 at the end of the outer slot 16 extends toward the inner side, and the first bending portion 22 is a combination of two arc segments and two straight segments, i.e. the first bending portion 22 is first curved and smoothly transited, then linearly extends toward the inner side, and then is curved and smoothly transited, and then linearly extends toward the adjacent first bending portion 22, so that the whole body is L-shaped or similar L-shaped. The simulation calculation analysis shows that compared with the design E-2, the design of the first bending part 22 of the design E-3 has higher mechanical sensitivity, and the stress of the diaphragm can be further reduced when the diaphragm bears the external forces such as the same external force impact, pressure, sound pressure or air blowing.

In designs E-1 and E-2, each outer groove 16 includes at least one first arc segment 16a, and each inner groove 18 includes at least one second arc segment 18a and at least one inner groove segment 18 b. The concave section 18b extends toward the inner side of the sensing portion 12 relative to the second circular arc section 18a, and the first circular arc section 16a and the second circular arc section 18a are concentric. The end of each first bending portion 22 extends into the recess 30 formed by the inner concave section 18b of the corresponding inner groove 18. It should be understood that the recess 30 formed by the concave section 18b belongs to a portion of the annular connecting arm 20, that is, the portion of the annular connecting arm 20 corresponding to the concave section 18b extends towards the inner side of the sensing portion 12.

In the designs E-2 and E-3, the difference from the design E-1 is that each inner groove 18 further includes at least one inclined section 18c, and the inclined section 18c extends obliquely toward the inner side of the sensing portion 12 with respect to the second circular arc section 18a to increase the radial width of the annular connecting arm 20 thereat to increase the mechanical strength thereof.

Through simulation tests and data analysis, the design forms that the tail end of the outer groove 16 extends inwards and the inner groove 18 is sunken inwards and the like can increase the effective sensing area of the diaphragm under the same diaphragm size compared with the design forms that the tail end of the outer groove extends outwards, so that the capacitance value between the diaphragm and the back plate is increased, and the learning-improving sensing performance of the diaphragm is improved.

As shown in fig. 1, each outer groove 16 includes a first arc segment 16a, and the first arc segment 16a is connected to the first bending portion 22 in a smooth transition manner. Each inner groove 18 is composed of an inner concave section 18b and two second arc sections 18a respectively connected to two ends of the inner concave section 18b, the inner concave section 18b is in smooth transition connection with the second arc section 18a, and the second arc section 18a is in smooth transition connection with the second bending part 24.

As shown in fig. 2, each outer groove 16 includes a first arc segment 16a, and the first arc segment 16a is connected to the first bending portion 22 in a smooth transition manner. Each inner groove 18 is composed of an inner concave section 18b, two second arc sections 18a respectively connected to two ends of the inner concave section 18b, and two inclined sections 18c respectively connected to ends of the two second arc sections 18a, the inner concave section 18b is in smooth transition connection with the second arc sections 18a, and the inclined sections 18c are in smooth transition connection with the second bending portions 24.

As shown in fig. 4 and 6, each outer groove 16 includes a first arc segment 16a, the first arc segment 16a is connected to the first bending portion 22 in a smooth transition manner, and two straight line segments of the first bending portion 22 are connected in a smooth transition manner. Each inner groove 18 is composed of an inner concave section 18b, two second arc sections 18a respectively connected to two ends of the inner concave section 18b, and two inclined sections 18c respectively connected to ends of the two second arc sections 18a, the inner concave section 18b is in smooth transition connection with the second arc sections 18a, and the inclined sections 18c are in smooth transition connection with the second bending portions 24.

A first connecting arm 26 is formed between two adjacent outer slots 16, and a second connecting arm 28 is formed between two adjacent inner slots 18, wherein in the illustrated embodiment, each first connecting arm 26 has the same structure and shape and the same circumferential width; each second connecting arm 28 is identical in structure and shape and also identical in circumferential width. The first connecting arm 26 extends outwardly from the outer edge of the annular connecting arm 20, the second connecting arm 28 extends inwardly from the inner edge of the annular connecting arm 20, and the first connecting arm 26 and the second connecting arm 28 are offset from each other in the circumferential direction of the annular connecting arm 20.

As previously described, the plurality of outer slots 16 and the plurality of inner slots 18 are symmetrically designed with respect to each other, e.g., the plurality of outer slots 16 and the plurality of inner slots 18 are both symmetrical about at least one diameter of the sensing portion 12. Specifically, in the present embodiment, each first connecting arm 26 corresponds to the position of the inner concave section 18b of the corresponding inner groove 18, each second connecting arm 28 corresponds to the central position of the first circular arc section 16a of the corresponding outer groove 16, and each inner concave section 18b is disposed at the central position of the corresponding inner groove 18, that is, the two second circular arc sections 18a of each inner groove 18 have the same shape and structure and the same circumferential width, and the spacing distance between each first bent part 22 and the side wall of the corresponding inner concave section 18b is the same. In the design E-3, one end of the inclined section 18c connected to the second bent portion 24 is inclined toward the inner side of the sensing portion 12, and the inclined section 18c of each inner groove 18 is inclined in the same direction and angle, so that the second connecting arm 28 is offset from the center position of the corresponding outer groove 16 toward the inner side of the sensing portion 12 by the same offset distance.

Referring to fig. 1, 2 and 4, the number of inner grooves and the number of outer grooves of the diaphragm of design E-1, the diaphragm of design E-2 and the diaphragm of design E-3 are all even, and the diaphragms are both symmetrical with respect to the diameter direction of the connecting line between the two opposite second connecting arms 28 and are also symmetrical with respect to the diameter direction of the connecting line between the two opposite first connecting arms 26 or the two opposite inner concave sections 18 b. In other embodiments, the number of inner grooves and the number of outer grooves may be odd, and the membranes may be symmetrical or asymmetrical.

In the design E-1, the annular connecting arm 20 has uniform radial width, and the arc angle curvature of the connecting part of the concave section 18b and the second arc section 18a is smaller; in the designs E-2 and E-3, the radial width of the portion of the annular connecting arm 20 adjacent to the second connecting arm 28 is larger than the radial width of the other portion of the annular connecting arm 20, for example, by inclining the portion at the end of the inner groove 18 toward the inner side to form the inclined section 18c and/or by arching the corresponding portion of the outer groove 16 toward the outer side, and the curvature of the arc angle at the connecting portion of the inner groove 18b and the second arc section 18a is larger.

The circumferential width of the first connecting arm 26 may be set to be greater than, equal to or less than the circumferential width of the second connecting arm 28 according to the specific design requirements and practical use of the MEMS membrane 10. In the present embodiment, the circumferential width of the first connecting arm 26 is greater than the circumferential width of the second connecting arm 28.

Thus, the peripheral portion 14 is integrally connected to the sensing portion 12 by the first connecting arm 26, the annular connecting arm 20 and the second connecting arm 28.

When the MEMS membrane 10 is subjected to an external pressure, the sensing portion 12 moves in a plane shape with respect to the peripheral portion 14 in a direction perpendicular to the membrane toward the direction of the applied pressure. From another perspective, the gap formed between the outer edge of sensing portion 12 and the inner edge of peripheral portion 14 is substantially uniform, as shown in fig. 3 and 5. At this time, the second connecting arm 28 moves vertically along with the sensing portion 12, and the annular connecting arm 20 is connected between the first connecting arm 26 and the second connecting arm 28 in a buckling manner.

In the use process, the MEMS membrane is fixed to an application scene such as an MEMS microphone through the fixed point, and in the MEMS membrane of the above embodiment, the annular connecting arm 20 and the second connecting arm 28 drive the sensing portion 12 to move, and the annular connecting arm 20 and the second connecting arm 28 are located far away from the fixed point, and are not affected by the position of the fixed point due to semiconductor process variation, so that the movement of the sensing portion 12 is insensitive to the position variation of the fixed point, thereby improving the sensing stability and reliability of the MEMS membrane.

In summary, the present invention provides a MEMS diaphragm, in which a plurality of outer grooves and a plurality of inner grooves are disposed between a sensing portion and an outer peripheral portion, ends of the outer grooves extend toward an inner side, and ends of the inner grooves extend toward the inner side. An annular connecting arm is formed between the outer grooves and the inner grooves, a first connecting arm is formed between every two adjacent outer grooves, and a second connecting arm is formed between every two adjacent inner grooves. A plurality of water jackets are the annular and arrange the inward flange in peripheral portion, and a plurality of inside grooves are the annular and arrange the outward flange in sensing portion, and the position that each inside groove corresponds two adjacent water jacket ends is inside sunken, so design can increase the effective area of diaphragm sensing portion, and the increase capacitance value has better acoustic sensing performance.

When the MEMS diaphragm is subjected to larger pressure intensity, the sensing part moves relative to the peripheral part in a plane shape along the direction vertical to the diaphragm, at the moment, the outer groove, the inner groove and the connecting arm form a pressure release path, external mechanical force can be released, and the diaphragm is not resisted by the external mechanical force, so that the mechanical reliability of the MEMS diaphragm and the MEMS sensor chip is improved. The first connecting arm and the second connecting arm are staggered in the circumferential direction, stress concentration can be reduced due to the arc design of the tail end of the outer groove and the tail end of the inner groove, the mechanical sensitivity of the sensing part is improved due to the tail end of the outer groove and the tail end of the inner groove which extend in a bent mode, and the reliability of the diaphragm is improved.

The concepts described herein may be embodied in other forms without departing from the spirit or characteristics thereof. The particular embodiments disclosed should be considered illustrative rather than limiting. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. Any changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. The MEMS diaphragm comprises a sensing part and a peripheral part surrounding the periphery of the sensing part, and is characterized in that a plurality of outer grooves and a plurality of inner grooves are arranged between the peripheral part and the sensing part, the outer grooves are annularly arranged on the inner edge of the peripheral part, the tail ends of the outer grooves extend towards the inner side of the diaphragm, the inner grooves are annularly arranged on the outer edge of the sensing part, the tail ends of the inner grooves extend towards the inner side of the diaphragm, and the parts of the inner grooves corresponding to the tail ends of two adjacent outer grooves are inwards sunken to form an inner section.

2. The MEMS diaphragm of claim 1 wherein each of said outer grooves includes at least a first arc segment and each of said inner grooves includes at least a second arc segment, said first arc segment being concentric with said second arc segment.

3. The MEMS diaphragm of claim 2, wherein each of said inner grooves further includes at least one inclined section extending obliquely toward an inner side of said sensing portion with respect to said second circular arc section.

4. The MEMS membrane of claim 1, wherein the end of the outer groove is provided with a first bending portion, the first bending portion comprises an arc-shaped section, a straight-line section or a combination of the arc-shaped section and the straight-line section, and the first bending portion extends into the recess of the corresponding inner groove; the tail end of the inner groove is provided with a second bending part, and the second bending part comprises an arc-shaped section, a straight-line section or a combination of the arc-shaped section and the straight-line section.

5. The MEMS diaphragm of claim 4,

the tail end of the first bending part is an arc-shaped tail end; or

The tail end of the second bending part is an arc-shaped tail end.

6. The MEMS membrane of any one of claims 1 to 5, wherein a first connecting arm is formed between two adjacent outer grooves, a second connecting arm is formed between two adjacent inner grooves, annular connecting arms are formed between the outer grooves and the inner grooves, the first connecting arm extends outward from an outer edge of the annular connecting arm and is connected to the outer peripheral portion, the second connecting arm extends inward from an inner edge of the annular connecting arm and is connected to the sensing portion, and the first connecting arm and the second connecting arm are offset from each other in a circumferential direction of the annular connecting arm.

7. The MEMS diaphragm of claim 6,

the annular connecting arms have a uniform radial width; or

The radial width of the part of the annular connecting arm adjacent to the second connecting arm is larger than that of other parts of the annular connecting arm.

8. The MEMS diaphragm according to claim 1, wherein the number of the outer grooves is 6 or less, and when the MEMS diaphragm is subjected to an external pressure, the sensing portion is substantially planar and moves relative to the peripheral portion in a direction perpendicular to the diaphragm.

9. The MEMS diaphragm of claim 6, wherein each outer groove corresponds to a pair of adjacent inner grooves in a radial direction of the diaphragm, and the second connecting arm between the pair of adjacent inner grooves is located opposite to or offset from a circumferential middle of the corresponding outer groove.

10. The MEMS diaphragm of claim 6, wherein a minimum circumferential width of said first connecting arm is greater than a minimum circumferential width of said second connecting arm.

11. A MEMS sensor chip, characterized in that it comprises a MEMS membrane according to any of claims 1 to 10.