CN111757223B

CN111757223B - MEMS microphone chip

Info

Publication number: CN111757223B
Application number: CN202010615637.7A
Authority: CN
Inventors: 柏杨; 张睿
Original assignee: AAC Acoustic Technologies Shenzhen Co Ltd
Current assignee: AAC Technologies Holdings Shenzhen Co Ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2021-12-14
Anticipated expiration: 2040-06-30
Also published as: WO2022000599A1; CN111757223A

Abstract

The invention provides an MEMS microphone chip, which comprises a substrate, a vibrating diaphragm and a back plate, wherein a back cavity is formed in the middle of the substrate, the vibrating diaphragm is arranged on the substrate, the back plate is arranged on one side, far away from the substrate, opposite to the vibrating diaphragm, a first vibration space is formed between the vibrating diaphragm and the substrate opposite to the vibrating diaphragm at an interval, the vibrating diaphragm extends towards the direction close to the substrate to form a blocking structure spaced from the substrate, and the orthographic projection of the blocking structure along the vibration direction of the vibrating diaphragm is positioned on the edge of one side, close to the back cavity, of the substrate. Through the blocking structure that sets up on the vibrating diaphragm, the effectual foreign matter of avoiding gets into first vibration space via the back of the body chamber, has improved MEMS microphone chip's reliability.

Description

MEMS microphone chip

[ technical field ] A method for producing a semiconductor device

The patent relates to the field of microphone design, in particular to a MEMS microphone chip design.

[ background of the invention ]

In recent years, mobile communication technology has been rapidly developed, and consumers increasingly use mobile communication devices, such as cellular phones, web-enabled cellular phones, personal digital assistants or other devices for communication in a private communication network, wherein a microphone is one of the important components, in particular a MEMS microphone.

In an actual working scene of the existing MEMS microphone chip, external foreign matters enter between the diaphragm and the substrate through the back cavity, so that the performance of the microphone is influenced by the capacitance of a system, and even the risk of short circuit is brought. Foreign matter can exist for a long time between vibrating diaphragm and the basement, produces contact repeated even collision with the vibrating diaphragm under the operating condition, makes the vibrating diaphragm produce the crackle. The initial microcrack can slowly expand under the action of alternating stress, and finally the diaphragm can break, so that the failure of the MEMS microphone chip is caused, and serious reliability hidden danger exists.

Therefore, it is necessary to provide a MEMS microphone chip that prevents foreign substances from entering.

[ summary of the invention ]

The invention aims to provide an MEMS microphone chip capable of preventing foreign matters from entering.

The technical scheme of the invention is as follows: an MEMS microphone chip comprises a substrate, a vibrating diaphragm and a back plate, wherein a back cavity is formed in the middle of the substrate, the vibrating diaphragm is arranged on the substrate, the back plate is arranged opposite to the vibrating diaphragm and far away from one side of the substrate, a first vibration space is formed between the vibrating diaphragm and the substrate opposite to the vibrating diaphragm at an interval, the vibrating diaphragm extends towards the direction close to the substrate to form a blocking structure spaced from the substrate, and the orthographic projection of the blocking structure along the vibration direction of the vibrating diaphragm is located on the edge of the substrate close to one side of the back cavity.

Preferably, the diaphragm comprises a sensing area located in the middle and a non-sensing area surrounding the sensing area and spaced from the sensing area to form a first gap.

More preferably, the blocking structure is disposed in the sensing region.

Preferably, the blocking structure comprises a first blocking structure arranged in the sensing region and a second blocking structure arranged in the non-sensing region.

Preferably, the first blocking structure and the second blocking structure are spaced to form a second gap.

Preferably, the first gap is communicated with the second gap, and the width of the second gap is smaller than that of the first gap.

More preferably, it is characterized in that: the blocking structure is one or the combination of a columnar blocking structure and a wall blocking structure.

More preferably, the barrier structures are arranged in one or more rows.

More preferably, the cross section of the columnar barrier structure is one or more of a circle, a fan or a polygon.

Preferably, the backplate with the vibrating diaphragm interval sets up and forms second vibration space, with the backplate middle part that the second vibration space corresponds is formed with the through-hole of a plurality of intervals settings, the backplate is in a plurality of the through-hole to extend to the one end that is close to the vibrating diaphragm forms anti-adhesion even post.

The invention has the beneficial effects that: according to the invention, the first vibration space is formed between the vibrating diaphragm and the substrate opposite to the vibrating diaphragm at intervals, and the blocking structure spaced from the substrate is formed by extending the vibrating diaphragm towards the direction close to the substrate, so that the back cavity of the substrate is isolated from the first vibration space, foreign matters are prevented from entering the first vibration space through the back cavity, and the reliability of the MEMS microphone chip structure is improved.

[ description of the drawings ]

FIG. 1 is a top view of a substrate structure according to the present invention;

FIG. 2 is a top view of a diaphragm structure according to the present invention;

FIG. 3 is an enlarged view of a portion of the area C in FIG. 2;

FIG. 4 is a cross-sectional view of the structure of FIG. 1 taken along line A-A of the substrate with the diaphragm and the backplate combined and the sensing region configured as a wall blocking structure;

FIG. 5 is a cross-sectional view of the substrate along line B-B of FIG. 1 in combination with a diaphragm and a backplate;

FIG. 6 is a cross-sectional view of a structure corresponding to the sensing region of FIG. 4 configured as a pillar-shaped blocking structure;

FIG. 7 is a cross-sectional view of the structure corresponding to FIG. 4 with both the sensing area and the non-sensing area configured as wall blocking structures;

FIG. 8 is a cross-sectional view of the structure corresponding to FIG. 4 in which the sensing region and the non-sensing region are both configured as a pillar-shaped blocking structure;

FIG. 9 is a cross-sectional view of one embodiment of the present invention in which both the sensing area and the non-sensing area corresponding to FIG. 4 are configured as wall barrier structures;

FIG. 10 is a cross-sectional view of another embodiment of the present invention in which the sensing region and the non-sensing region corresponding to FIG. 4 are both configured as a pillar-shaped barrier structure;

fig. 11 is a partially enlarged view of a region D in fig. 9.

[ detailed description ] embodiments

The invention is further described with reference to the following figures and embodiments.

Referring to fig. 1, 4 and 5, the present invention provides a MEMS microphone chip 100, where the chip 100 includes a substrate 10, a back plate 20 and a diaphragm 30, the substrate 10 includes a back cavity 12 formed in the middle of the substrate 10 and a fixing portion 11 surrounding the back cavity 12, the back plate 20 and the diaphragm 30 are fixed on the fixing portion 11, the diaphragm 30 is disposed between the substrate 10 and the back plate 20, the diaphragm 30 and the back plate 20 are disposed at an interval to form a capacitor structure, the diaphragm 30 and the substrate 10 opposite thereto are disposed at an interval to form a first vibration space 41, and the diaphragm 30 and the back plate 20 are disposed at an interval to form a second vibration space 44.

Specifically, the back plate 20 and the diaphragm 30 form a capacitor structure, a second vibration space 44 is formed by a gap between the back plate 20 and the diaphragm 30, a plurality of through holes 21 are formed in the middle of the back plate 20 corresponding to the second vibration space 44, the through holes 21 are arranged at intervals to pass external sound pressure through the through holes 21 in the back plate 20, so that the diaphragm 30 is caused to move, and the movement changes the distance between the diaphragm 30 and the back plate 20, further changes the capacitor and finally converts the capacitor into an electric signal.

Referring to fig. 4 to 10, the back plate 20 is formed with an anti-adhesion column 22 in the second vibration space 44 near one end of the diaphragm 30, and the anti-adhesion column 22 is formed by extending the back plate 20 between the through holes 21 to the end near the diaphragm 30, so as to prevent the diaphragm 30 from adhering to the back plate 20 during vibration.

Referring to fig. 4 to 10, the diaphragm 30 extends toward the substrate 10 to form a blocking structure 50, the blocking structure 50 is spaced apart from the substrate 10, and an orthographic projection of the blocking structure 50 along the vibration direction of the diaphragm 30 is located on an edge 12a of the substrate 10 on a side close to the back cavity 12. The blocking structure 50 reduces the distance between the diaphragm 30 and the substrate 10 at the edge 12a, so as to effectively block foreign matters and avoid the influence of the foreign matters on the performance of the microphone.

Referring to fig. 2, the diaphragm 30 includes a sensing region 31 and non-sensing regions 32 spaced around the sensing region 31, the sensing region 31 includes an anchor portion 311, the anchor portion 311 extends to the fixing portion 11 of the substrate 10, and the anchor portion 311 of the sensing region 31 is fixed to the fixing portion 11 of the substrate 10. The non-sensing area 32 surrounds the sensing area 31, the sensing area 31 and the non-sensing area 32 are arranged in a gap mode to form a first gap 43, and the non-sensing area 32 is fixed with the substrate 10.

Preferably, the blocking structure 50 may be disposed only in the sensing region 31 of the diaphragm 30, or may be disposed in both the sensing region 31 and the non-sensing region 32 of the diaphragm 30. Stop structure 50 and set up in response area 31, can prevent effectively that the foreign matter from getting into the response vibrating diaphragm, avoid the foreign matter to get into the response vibrating diaphragm and cause the influence to the microphone, prevent that the vibrating diaphragm is punctureed to the foreign matter, lead to whole microphone to become invalid. The blocking structure 50 is disposed in the non-sensing region 32 to prevent foreign materials from entering and reduce the width of the first gap, thereby affecting the low frequency performance of the microphone.

Referring to fig. 4 to 6, when the blocking structure 50 is only disposed in the sensing region 31 of the diaphragm 30, the blocking structure 50 is formed by extending the sensing region 31 of the diaphragm 30 from a position, corresponding to the first vibration space 41, close to the back cavity 12 to a direction close to the substrate 10, and when entering from the back cavity 12, a foreign object is blocked by the blocking structure 50, so that the foreign object is difficult to enter into the first vibration space 41, that is, the foreign object is prevented from entering between the diaphragm 30 and the substrate 10 through the back cavity 12.

Referring to fig. 7 and 8, when the blocking structure 50 is disposed in both the sensing region 31 and the non-sensing region 32 of the diaphragm 30, the blocking structure 50 includes a first blocking structure 51 and a second blocking structure 52, the first blocking structure 51 is disposed in the sensing region 31, and the second blocking structure 52 is disposed in the non-sensing region 32. The position of the first blocking structure 51 in the sensing region 31 and the position of the second blocking structure 52 in the non-sensing region 32 both correspond to the position of the first vibration space 41 near the back cavity 12, so as to prevent foreign matters from entering between the diaphragm 30 and the substrate 10 through the back cavity 12.

Preferably, the first blocking structure 51 and the second blocking structure 52 are spaced apart to form a second gap 53, and the first gap 43 is communicated with the second gap 53. As shown in fig. 7 to 11, the width W2 of the second slit 53 is smaller or larger than the width W1 of the first slit 43, and when the width W2 of the second slit 53 is larger than the width W1 of the first slit 43, referring to fig. 7 and 8, it is possible to effectively prevent foreign substances from entering the second vibration space 44 between the diaphragm 30 and the backplate 20 through the second slit 53. Referring to fig. 9 and 10, when the width W2 of the second slit 53 is smaller than the width W1 of the first slit 43, it is possible to effectively prevent foreign substances from entering the second vibration space 44 between the diaphragm 30 and the back plate 20 through the first slit 43.

Referring to fig. 4 to 10, the barrier structure 50 is one or a combination of a columnar barrier structure and a wall barrier structure. In one embodiment, the blocking structure 50 is a wall blocking structure that effectively prevents most foreign objects from entering the first vibration space 41; in another embodiment, the blocking structure 50 is a cylindrical blocking structure, which blocks the large foreign objects by using a narrow gap between the cylinders, so as to prevent the foreign objects from entering the first vibration space 41. Referring to fig. 5, the barrier structures 50 of the sensing region 31 are arranged in one or more rows, and the barrier structures 50 in this embodiment are arranged in two rows. The cross section of the columnar blocking structure is one or a combination of a plurality of circular, fan-shaped or polygonal shapes. The cross section of the columnar barrier structure in the present embodiment in the direction parallel to the substrate top surface 11 is circular, so that a large volume of foreign matter is blocked from entering the first vibration space 41 by a narrow gap between the columns.

While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.

Claims

1. The MEMS microphone chip is characterized by comprising a substrate, a vibrating diaphragm and a back plate, wherein a back cavity is formed in the middle of the substrate, the vibrating diaphragm is arranged on the substrate, the back plate is arranged on one side, far away from the substrate, of the vibrating diaphragm, a first vibrating space is formed between the vibrating diaphragm and the substrate, which is opposite to the vibrating diaphragm, at intervals, the vibrating diaphragm is fixed on the substrate, the vibrating diaphragm extends towards the direction close to the substrate to form a blocking structure which is spaced from the substrate, and the orthographic projection of the blocking structure along the vibrating direction of the vibrating diaphragm is located on the edge, close to one side of the back cavity, of the substrate.

2. The MEMS microphone chip of claim 1, wherein: the diaphragm comprises an induction area positioned in the middle and a non-induction area surrounding the induction area and spaced from the induction area to form a first gap.

3. The MEMS microphone chip of claim 2, wherein: the blocking structure is arranged in the sensing area.

4. The MEMS microphone chip of claim 2, wherein: the blocking structure comprises a first blocking structure arranged in the sensing area and a second blocking structure arranged in the non-sensing area.

5. The MEMS microphone chip of claim 4, wherein: the first blocking structure and the second blocking structure are separated to form a second gap.

6. The MEMS microphone chip of claim 5, wherein: the first gap is communicated with the second gap, and the width of the second gap is smaller than that of the first gap.

7. The MEMS microphone chip of any one of claims 1 to 6, wherein: the blocking structure is one or the combination of a columnar blocking structure and a wall blocking structure.

8. The MEMS microphone chip of claim 7, wherein: the barrier structures are arranged in one or more rows.

9. The MEMS microphone chip of claim 7, wherein: the cross section of the columnar blocking structure is one or a combination of a plurality of circular, fan-shaped or polygonal shapes.

10. The MEMS microphone chip of claim 1, wherein: the backplate with the vibrating diaphragm interval sets up and forms second vibration space, with the backplate middle part that the second vibration space corresponds is formed with the through-hole of a plurality of intervals settings, the backplate is in a plurality of between the through-hole to being close to the one end of vibrating diaphragm extends and forms anti-adhesion and links the post.