CN212486785U

CN212486785U - MEMS microphone

Info

Publication number: CN212486785U
Application number: CN202021509107.6U
Authority: CN
Inventors: 袁兆斌
Original assignee: Weifang Goertek Microelectronics Co Ltd
Current assignee: Weifang Goertek Microelectronics Co Ltd
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2021-02-05
Anticipated expiration: 2030-07-27

Abstract

The utility model discloses a MEMS microphone, MEMS microphone includes casing and MEMS chip; the shell comprises a substrate with a sound hole, and a step part positioned on the periphery of the sound hole is arranged on the inner surface of the substrate; the MEMS chip sets up in the casing and shroud the sound hole, the periphery wall of MEMS chip is provided with the overlap joint groove, the overlap joint groove overlap joint is in on the step part to through viscous material with step part adhesive bonding. The utility model discloses a MEMS microphone, the viscous material side direction trickling that can reduce bonding MEMS chip appears to the condition in sound hole.

Description

MEMS microphone

Technical Field

The utility model relates to a microphone technical field, in particular to MEMS microphone.

Background

A MEMS (micro electro mechanical system) microphone is a microphone manufactured based on MEMS technology, and can be applied to electronic equipment as an acoustic-electric conversion device. The substrate of a conventional MEMS microphone is usually a flat plate; the MEMS chip of the MEMS microphone covers the sound hole on the substrate and is adhered to the substrate through an adhesive material. However, in the process of bonding the MEMS chip, the adhesive material may easily flow along the surface of the substrate laterally into the sound hole and adhere to the inner wall of the sound hole, so that the aperture of the sound hole is reduced, and the acoustic resistance of the MEMS microphone is increased, so that the signal-to-noise ratio of the MEMS microphone is poor.

SUMMERY OF THE UTILITY MODEL

The main object of the present invention is to provide a MEMS microphone, which can reduce the occurrence of the situation that the viscous material adhered to the MEMS chip flows laterally to the sound hole of the substrate.

In order to achieve the above object, the present invention provides a MEMS microphone, which includes a housing and a MEMS chip; the shell comprises a substrate with a sound hole, and a step part positioned on the periphery of the sound hole is arranged on the inner surface of the substrate; the MEMS chip sets up in the casing and shroud the sound hole, the periphery wall of MEMS chip is provided with the overlap joint groove, the overlap joint groove overlap joint is in on the step part to through viscous material with step part adhesive bonding.

Optionally, the step part has a step bottom surface, a step top surface and a step side surface connecting the step bottom surface and the step top surface; the lapping groove is provided with a first lapping surface and a second lapping surface which is arranged at a right angle with the first lapping surface; the first lapping surface is correspondingly matched with the top surface of the step, and the second lapping surface is correspondingly matched with the side surface of the step.

Optionally, the adhesive material is provided on the step top surface to be adhesively connected to the first overlapping surface by the adhesive material.

Optionally, the MEMS chip includes a main body portion having a diaphragm, and a connecting portion extending downward from a periphery of the main body portion, and an outer peripheral edge of a lower end of the connecting portion is configured to form the overlapping groove.

Optionally, the connecting portion is formed with an annular portion on one side of the overlapping groove, an outer side surface of the annular portion forms a second overlapping surface of the overlapping groove, and a lower end surface of the annular portion is opposite to the step bottom surface and is arranged at an interval.

Optionally, a distance between a lower end surface of the annular portion and the bottom surface of the step ranges from 0.01mm to 0.05 mm.

Optionally, the adhesive material is glue or bonding glue.

Optionally, the MEMS microphone further includes an ASIC chip, and the ASIC chip is mounted on the substrate and electrically connected to the MEMS chip.

Optionally, the ASIC chip is located on a side of the step top surface away from the MEMS chip, and is electrically connected to the MEMS chip through a metal wire.

Optionally, the housing further includes a cover disposed on the substrate, and a lower periphery of the cover is connected to the substrate to form an encapsulation cavity encapsulating the MEMS chip.

The technical scheme of the utility model, be located through the internal surface setting at the base plate the step portion of phonate hole ring week, and the periphery wall of MEMS chip is provided with the overlap joint groove, the overlap joint groove overlap joint be in on the step portion, then through viscous material with the step portion bonds. The MEMS chip is in lap joint with the step part of the substrate through the lap joint groove, so that a step corner is formed at the lap joint position of the MEMS chip and the step groove, the flow resistance of the step corner to the viscous material is large, the viscous material adhered to the MEMS chip is difficult to flow to the sound hole, and the situation that the viscous material flows to the sound hole of the substrate can be avoided.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a conventional MEMS microphone;

fig. 2 is a schematic structural diagram of an embodiment of the MEMS microphone of the present invention;

FIG. 3 is an enlarged view taken at A in FIG. 2;

fig. 4 is an exploded view of the MEMS microphone of fig. 2;

FIG. 5 is an enlarged view at B in FIG. 4;

fig. 6 is an enlarged view at C in fig. 4.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				100	Shell body	300	MEMS chip
110	Substrate	310	Main body part
				111	Sound hole	320	Connecting part
120	Sealing cover	321	Overlapping groove
				112	Step part	321a	First overlapping surface
112a	Step top	322b	Second overlapping surface
				112c	Bottom surface of step	322	Annular portion
112b	Step side	400	ASIC chip
				200	Adhesive material

The purpose of the present invention is to provide a novel and improved method and apparatus for operating a computer.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that, if directional indications (such as upper, lower, left, right, front and rear … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

Referring to fig. 1, the conventional MEMS microphone includes a case 100 and a MEMS chip 300; the substrate 110 of the housing 100 is a flat plate, and the middle of the substrate 110 is penetrated with a sound hole 111; the MEMS chip 300 covers the acoustic hole 111 on the substrate 110, and the periphery of the MEMS chip 300 is adhered to the inner surface of the substrate 110 by the adhesive material 200. Since the basic inner surface is flat, the viscous material 200 tends to flow laterally along the inner surface of the substrate 110 into the acoustic hole 111 during the attachment of the MEMS chip 300. The viscous material 200 flowing to the sound hole 111 is solidified and attached to the inner wall of the sound hole 111, and occupies a part of the inner space of the sound hole 111, so that the aperture of the sound hole 111 is reduced, the acoustic resistance of the MEMS microphone is increased, and the signal-to-noise ratio of the MEMS microphone is poor.

Referring to fig. 2 to 4, the present invention provides an embodiment of a MEMS microphone for solving the above technical problem, in which the situation that the adhesive material 200 adhered to the MEMS chip 300 flows laterally to the sound hole 111 can be reduced, so as to protect the sound hole 111, thereby improving the signal-to-noise ratio of the MEMS microphone. It should be noted that the MEMS microphone may be applied to electronic devices such as a mobile phone, a tablet, a notebook computer, and a sensor.

Referring to fig. 2 to 4, in an embodiment of the MEMS microphone of the present invention, the MEMS microphone includes a housing 100 and a MEMS chip 300; the casing 100 includes a substrate 110, the substrate 110 is provided with a sound hole 111, and the inner surface of the substrate 110 is provided with a step 112 around the sound hole 111; the MEMS chip 300 is disposed in the case 100 and covers the sound hole 111, and the outer peripheral wall of the MEMS chip 300 is provided with a lap groove 321, and the lap groove 321 is lapped on the step portion 112 and bonded to the step portion 112 by an adhesive material.

Specifically, the substrate 110 of the housing 100 is a PCB board on which a circuit is integrated. The housing 100 further includes a cover 120 disposed on the substrate 110, the cover 120 is made of a metal material, the cover 120 covers the substrate 110, and a lower periphery of the cover 120 is connected to the substrate 110 to form a package cavity 101 with the substrate 110. The MEMS chip 300 is encapsulated in the encapsulation cavity 101 of the housing 100, and the MEMS chip 300 covers the acoustic hole 111. The MEMS chip 300 is used to sense sound pressure and convert the sound pressure into an electrical signal.

For the substrate 110, a sound hole 111 is formed through the middle part of the substrate 110; the stepped portion 112 of the substrate 110 is wound around the circumference of the sound hole 111 by one full turn. In the process of bonding the MEMS chip 300, the adhesive material 200 may be first added on the top surface of the step portion 112 of the substrate 110, then the overlapping groove 321 on the periphery of the MEMS chip 300 is overlapped on the step portion 112 of the substrate 110, so that the MEMS chip 300 and the substrate 110 are bonded and fixed, and finally the cap 120 is mounted. It should be noted that the adhesive material 200 should be a material with better adhesiveness, such as glue, bonding glue or other adhesives.

The technical scheme of the utility model, set up the step portion 112 that is located the sound hole 111 circumference through the internal surface at base plate 110 to be provided with overlap joint groove 321 at the periphery wall of MEMS chip 300, overlap joint groove 321 overlap joint is on step portion 112, then bonds through viscous material 200 and step portion 112's top surface. Since the MEMS chip 300 is in lap joint with the step 112 of the substrate 110 through the lap joint groove 321, a step corner is formed at the lap joint position of the two, and the flow resistance of the step corner to the viscous material 200 is large, so that the viscous material 200 adhered to the MEMS chip 300 is difficult to flow to the sound hole 111, and thus the occurrence of the situation that the viscous material 200 flows to the sound hole 111 of the substrate 110 can be reduced, a part of the inner space of the sound hole 111 is occupied, the aperture of the sound hole 111 is reduced, the sound resistance of the MEMS microphone is increased, and the signal-to-noise ratio of the MEMS microphone is poor.

Referring to fig. 4 to 6, in an embodiment, for the step portion 112 of the substrate 110, the step portion 112 may be a first step or a second step. In the present embodiment, the step part 112 is provided as a one-step, and the overlapping groove 321 should be adapted to the shape of the step part 112. Alternatively, the step portion 112 has a step top surface 112a, a step bottom surface 112c, and a step side surface 112b connecting the step top surface 112a and the step bottom surface 112 c; accordingly, the lap groove 321 has a first lap surface 321a and a second lap surface 321b disposed at right angles to the first lap surface 321 a; wherein the first overlapping surface 321a is engaged with the step top surface 112a and the second overlapping surface 321b is engaged with the step side surface 112 b.

Specifically, an adhesive material 200 is provided on the step top surface 112a to be adhesively connected to the first overlapping surface 112a via the adhesive material 200. When the MEMS chip 300 is bonded, the adhesive material 200 is added to the step top surface 112a of the step portion 112 of the substrate 110; then, the bonding groove 321 of the MEMS chip 300 is placed on the step portion 112 of the substrate 110 from top to bottom, and then the MEMS chip 300 is pressed downward (as shown by the dotted arrow in fig. 4), so that the adhesive material 200 is pressed to spread over the first bonding surface 321a, and the first bonding surface 321a and the step top surface 112a are hermetically connected in a large area, thereby improving the air tightness. In this process, the second lap surface 321b is kept in contact with the step side surface 112b, so that the gap between the second lap surface 321b and the step side surface 112b is extremely small or zero, and the extruded adhesive material 200 is less likely to leak from between the second lap surface 321b and the step side surface 112b and to flow down to the sound hole 111.

Referring to fig. 4 to 6, according to any of the above embodiments, the MEMS chip 300 includes a main body 310 having a diaphragm, and a connecting portion 320 extending downward from a periphery of the main body 310, wherein a lap joint groove 321 is formed at an outer peripheral edge of a lower end of the connecting portion 320. The main body part 310 of the MEMS chip 300 is provided with a diaphragm, and the diaphragm is located above the sound hole 111; the connection portion 320 of the MEMS chip 300 is hermetically connected to the step portion 112 of the substrate 110 through the bonding groove 321 to form the package cavity 101 between the MEMS chip 300 and the inner side of the substrate 110.

Further, the connecting portion 320 is formed with an annular portion 322 at one side of the overlapping groove 321, an outer side surface of the annular portion 322 is formed with a second overlapping surface 321b of the overlapping groove 321, and a lower end surface 322a of the annular portion 322 faces the step bottom surface 112c of the step portion 112. It is considered that if the lower end surface 322a of the annular portion 322 contacts the first bridging surface 321a, when the MEMS chip 300 is pressed downward in the process of bonding the MEMS chip 300, the lower end surface 322a of the annular portion 322 is pressed downward to contact and abut against the step bottom surface 112c, and further the MEMS chip 300 cannot be pressed downward, so that it is difficult to ensure the hermeticity of the connection between the first bridging surface 321a and the step top surface 112 a.

To solve the above technical problem, optionally, the lower end surface 322a of the annular portion 322 is opposite to and spaced from the step bottom surface 112 c. That is, the lower end surface 322a of the annular portion 322 is suspended above the step bottom surface 112c, so that a space is reserved between the lower end surface 322a of the annular portion 322 and the step bottom surface 112c, and the lower end surface 322a of the annular portion 322 is prevented from contacting and abutting against the step bottom surface 112c, so that the lapping groove 321 of the MEMS chip 300 can be pressed onto the adhesive material 200 on the step portion 112 in the process of bonding the MEMS chip 300.

As shown in fig. 3, D in fig. 3 represents the distance between the lower end surface of the annular portion 322 and the step bottom surface 112 c. The size of the distance can be reasonably designed according to the size of the MEMS microphone. Alternatively, the distance between the lower end surface 322a of the annular portion 322 and the step bottom surface 112c may be in a range of 0.01mm to 0.05mm, and may specifically be, but is not limited to: 0.02mm, 0.03mm, 0.04mm, 0.05mm, etc. If the pitch is less than 0.01mm, the first pitch is too small, and the ring portion 322 easily abuts against the step bottom surface 112c, resulting in difficulty in pressing the MEMS chip 300 onto the adhesive material 200. If the distance is larger than 0.05mm, the distance is too large, the distance occupies a larger longitudinal space, the overall volume of the MEMS microphone is further increased, and the micro-design of the MEMS microphone is not facilitated. Therefore, the pitch is preferably kept in the range of 0.01mm to 0.05 mm.

Referring to fig. 2, according to any of the above embodiments, the MEMS microphone further includes an ASIC chip 400, the ASIC chip 400 is mounted on the substrate 110 and electrically connected to the MEMS chip 300, and the ASIC chip 400 is used for processing an electrical signal. Specifically, the ASIC chip 400 is electrically connected to the MEMS chip 300 through a metal wire.

Further, the ASIC chip 400 is mounted on the step top surface 112a of the step portion 112 and located on the side of the MEMS chip 300 away from the step top surface 112a, so that the ASIC chip 400 is away from the adhesive material 200, and the ASIC chip 400 is prevented from being damaged by contacting the adhesive material 200.

The above only be the preferred embodiment of the utility model discloses a not consequently restriction the utility model discloses a patent range, all are in the utility model discloses a conceive, utilize the equivalent structure transform of what the content was done in the description and the attached drawing, or direct/indirect application all is included in other relevant technical field the utility model discloses a patent protection within range.

Claims

1. A MEMS microphone, comprising:

the shell comprises a substrate with a sound hole, and a step part positioned on the periphery of the sound hole is arranged on the inner surface of the substrate; and

the MEMS chip sets up in the casing and shroud the sound hole, the periphery wall of MEMS chip is provided with the overlap joint groove, the overlap joint groove overlap joint is in on the step part to through viscous material with step part adhesive bonding.

2. The MEMS microphone of claim 1, wherein the step has a step top surface, a step bottom surface, and a step side surface connecting the step bottom surface and the step top surface;

the lapping groove is provided with a first lapping surface and a second lapping surface which is arranged at a right angle with the first lapping surface; the first lapping surface is correspondingly matched with the top surface of the step, and the second lapping surface is correspondingly matched with the side surface of the step.

3. The MEMS microphone of claim 2, wherein the adhesive material is provided on the top surface of the step to be adhesively connected to the first land by the adhesive material.

4. The MEMS microphone of claim 2, wherein the MEMS chip comprises a main body portion having a diaphragm, and a connection portion extending downward from a circumference of the main body portion, the connection portion having an outer circumferential edge at a lower end thereof configured to form the lap joint groove.

5. The MEMS microphone as claimed in claim 4, wherein the connection part is formed with a ring part at one side of the lap groove, an outer side surface of the ring part forms a second lap surface of the lap groove, and a lower end surface of the ring part is disposed opposite to and spaced apart from the step bottom surface.

6. The MEMS microphone of claim 5, wherein a distance between a lower end surface of the ring part and a bottom surface of the step is in a range of 0.01mm to 0.05 mm.

7. The MEMS microphone of any one of claims 1 to 6, wherein the adhesive material is glue or bonding glue.

8. The MEMS microphone of any one of claims 1 to 6, further comprising an ASIC chip mounted on the substrate and electrically connected to the MEMS chip.

9. The MEMS microphone of claim 8, wherein the ASIC chip is located on a side of the step top surface remote from the MEMS chip and electrically connected to the MEMS chip by a metal wire.

10. The MEMS microphone of any one of claims 1 to 6, wherein the housing further comprises a cover disposed on the substrate, a lower periphery of the cover being connected to the substrate to enclose with the substrate to form an encapsulation cavity encapsulating the MEMS chip.