MEMS package structure

Abstract

Provided in the present utility model is an MEMS package structure, comprising a housing, a circuit board that covers the housing to form an accommodating space, and an MEMS chip and an ASIC chip that are disposed in the accommodating space. The MEMS chip comprises a vibrating diaphragm and a backplate spaced apart from the vibrating diaphragm. The MEMS chip is disposed on the circuit board. The circuit board comprises an upper surface connected to the MEMS chip and a lower surface. The circuit board is further provided with a first sound hole extending from the lower surface towards the upper surface but not passing through the upper surface, a second sound hole extending from the upper surface towards the lower surface but not passing through the lower surface, and a communication passage arranged between the upper surface and the lower surface and interconnecting the first sound hole and the second sound hole. The MEMS chip covers the second sound hole, projections of the first sound hole and the second sound hole in the vibrating direction of the vibrating diaphragm not overlapping each other. A plurality of protruding structures are provided in the communication passage, the protruding structures allowing the pressure of an air flow entering from the first sound hole to be 2-3.5 times the pressure of an air flow flowing out of the second sound hole. The MEMS package structure provided in the present utility model has a strong anti-blowing capability.

Description

MEMS packaging structure TECHNICAL FIELD

[0001] The utility model relates to the field of electroacoustic conversion especially relates to a MEMS packaging structure. BACKGROUND

[0002] MEMS (Microelectro Mechanical Systems) packaging structure is the packaging structure based on MEMS sensor technology, has the improved noise elimination performance, good radio frequency performance and electromagnetic interference suppression ability, is widely used in intelligent mobile phone, line control earphone, tablet computer and notebook computer etc. TECHNICAL PROBLEM

[0003] The related art MEMS packaging structure includes a shell, a circuit board in covering connection with the shell to form a containing space, and an ASIC chip and a MEMS chip placed in the containing space, the MEMS chip is placed on the circuit board, the diaphragm of the MEMS chip divides the containing space into a front cavity and a rear cavity, the circuit board is provided with a through hole in communication with the front cavity, after the atmospheric pressure enters from the through hole, the airflow directly acts on the diaphragm of the MEMS chip, which is easy to cause the diaphragm to break, and the anti-blowing ability of the MEMS packaging structure is weak.

[0004] Therefore, it is necessary to provide a new MEMS packaging structure to solve the above technical problems. TECHNICAL SOLUTION

[0005] The utility model discloses a kind of MEMS packaging structures with strong anti-blowing ability.

[0006] To achieve the above purpose, the utility model provides a kind of MEMS packaging structure, it includes shell, with the shell cover and form the containing space of circuit board and be placed in the MEMS chip and ASIC chip of containing space, the MEMS chip includes diaphragm and the back plate spaced apart with the diaphragm, the MEMS chip is fixed on the circuit board, the circuit board includes the upper surface connected with the MEMS chip and the lower surface opposite to the upper surface, the circuit board is also provided with from the lower surface to the upper surface extension and not through the first sound hole of the upper surface, from the upper surface to the lower surface extension and not through the second sound hole of the lower surface, be placed between the upper surface and the lower surface and the communication channel of the first sound hole and the second sound hole, the MEMS chip covers the second sound hole, the projection of the first sound hole and the second sound hole along the diaphragm vibration direction does not overlap each other, the communication channel is equipped with several convex structures, the convex structure makes that the pressure of airflow from the first sound hole entering is 2-3.5 times of the pressure of airflow from the second sound hole.

[0007] Preferably, the protruding structures extend from the lower surface and do not contact the upper surface, or the protruding structures extend from the upper surface and do not contact the lower surface.

[0008] Preferably, the circuit board is a laminated circuit board, which comprises a first circuit board connected with the MEMS chip, a second circuit board arranged apart from the first circuit board, and a third circuit board between the first circuit board and the second circuit board, the third circuit board being a hollow ring structure, the second acoustic hole penetrating through the first circuit board, and the first acoustic hole penetrating through the second circuit board.

[0009] Preferably, the arrangement of the protruding structures is a Tesla valve structure.

[0010] Preferably, the protruding structures are arranged such that the airflow entering from the first acoustic hole reaches the second acoustic hole along at least two different paths.

[0011] Preferably, the airflow entering from the first acoustic hole generates turbulent flow after contacting the protruding structures to reduce the pressure of the airflow.

[0012] Preferably, the protruding structures are flat plate structures, and the included angle between adjacent protruding structures is 10-170°.

[0013] Preferably, the protruding structures are flat plate structures, and / or arc-shaped plate structures, and / or arc-shaped block structures.

[0014] Preferably, the number of the protruding structures is 1-1000.

[0015] Preferably, the diaphragm is closer to the circuit board than the back plate. Advantages

[0016] Compared with the related art, the MEMS packaging structure provided by the utility model has the shell, the circuit board which forms the containing space with the shell cover and the MEMS chip and the ASIC chip which are placed in the containing space, the MEMS chip includes the diaphragm and the back plate which is arranged at intervals with the diaphragm, the MEMS chip is fixed to the circuit board, the circuit board includes the upper surface which is connected with the MEMS chip and the lower surface which is opposite to the upper surface, the circuit board is also provided with the first sound hole which extends from the lower surface to the upper surface and does not pass through the upper surface, the second sound hole which extends from the upper surface to the lower surface and does not pass through the lower surface, the communication channel which is arranged between the upper surface and the lower surface and communicates the first sound hole and the second sound hole, the MEMS chip covers the second sound hole, the projection of the first sound hole and the second sound hole along the vibration direction of the diaphragm does not overlap each other, a plurality of convex structures are arranged in the communication channel, the convex structures make the pressure of the airflow which enters from the first sound hole be 2-3.5 times of the pressure of the airflow which flows out from the second sound hole. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the drawings needed to be used in the embodiment description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creating labor, wherein:

[0018] Fig. 1 is the sectional view of the MEMS packaging structure provided by the first embodiment of the utility model;

[0019] Fig. 2 is the sectional view of the circuit board in the MEMS packaging structure provided by the first embodiment of the utility model;

[0020] Fig. 3 is the sectional view of the circuit board in the MEMS packaging structure provided by the second embodiment of the utility model;

[0021] Fig. 4 is the sectional view of the circuit board in the MEMS packaging structure provided by the third embodiment of the utility model;

[0022] Fig. 5 is the sectional view of the circuit board in the MEMS packaging structure provided by the fourth embodiment of the utility model;

[0023] Fig. 6 is the sectional view of the circuit board in the MEMS packaging structure provided by the fifth embodiment of the utility model. Best mode for carrying out the invention

[0024] The technical solutions in the embodiments of the utility model will be apparently and completely described in connection with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the utility model.

[0025] Please refer to Fig. 1 and Fig. 2, Fig. 1 is the sectional view of the MEMS packaging structure 100 provided by the first embodiment of the utility model, the utility model provides a kind of MEMS packaging structure 100, including shell 1, circuit board 2 with the shell 1 cover and form the accommodation space 101 and place in the accommodation space 101 MEMS chip 3 and ASIC chip 4, MEMS chip 3 is connected with circuit board 2.The shell 1 is made of metal material.The MEMS chip 3 includes diaphragm 31 and back plate 32 spaced apart from the diaphragm 31, and the diaphragm 31 and back plate 32 form a capacitor structure.In the present embodiment, diaphragm 31 is set to be closer to circuit board 2 than back plate 32, and in other embodiments, back plate 32 can also be set to be closer to circuit board 2 than diaphragm 31.

[0026] Fig. 2 is the sectional view along the thickness direction of circuit board 2 in Fig. 1, please refer to Fig. 1, Fig. 2, the circuit board 2 includes upper surface 201 connected with the MEMS chip 3 and lower surface 202 opposite to the upper surface 201, the circuit board 2 is also provided with first sound hole 21 extending from the lower surface 202 to the upper surface 201 and not passing through the upper surface 201, second sound hole 22 extending from the upper surface 201 to the lower surface 202 and not passing through the lower surface 202, communication channel 23 arranged between the upper surface 201 and the lower surface 202 and communicating the first sound hole 21 and the second sound hole 22, the MEMS chip 3 covers the second sound hole 22, the projection of the first sound hole 21 and the second sound hole 22 along the vibration direction of the diaphragm 31 does not overlap each other, so as to prevent dust from falling on the MEMS chip 3, and also can buffer the impact of external airflow, improve the reliability of product.The communication channel 23 is provided with a plurality of protruding structures 24, the protruding structure 24 makes the pressure of the airflow entering from the first sound hole 21 be 2-3.5 times of the pressure of the airflow flowing out from the second sound hole 22.

[0027] The protruding structure 24 extends from the lower surface 202 and does not contact the upper surface 201, or the protruding structure 24 extends from the upper surface 201 and does not contact the lower surface 202, the protruding structure 24 is formed on the circuit board 2 by precision milling or deposition etching process, and the height-width ratio of the protruding structure 24 is 0.1-8.

[0028] The circuit board 2 is a laminated circuit board, which comprises a first circuit board 25 connected with the MEMS chip 3, a second circuit board 26 arranged in a spaced manner with the first circuit board 25, and a third circuit board 27 located between the first circuit board 25 and the second circuit board 26, the third circuit board 27 is a hollow ring structure, the second sound hole 22 penetrates the first circuit board 25, and the first sound hole 21 penetrates the second circuit board 26. The upper surface 201 is located on the first circuit board 25, the lower surface 202 is located on the second circuit board 26, and the first sound hole 21 and the second sound hole 22 are located at the center line position in the long axis direction of the circuit board 2.

[0029] The protruding structure 24 is arranged in a symmetrical manner with the center line of the circuit board 2 as the center.

[0030] As shown in FIG. 2, it is the first embodiment of the utility model, the protruding structure 24 is flat plate structure, the included angle between adjacent protruding structure 24 is 10-170 °, the number of protruding structure 24 is 1-1000. The protruding structure 24 is arranged in a symmetrical manner with the center line of the circuit board 2 as the center.

[0031] As shown in FIG. 3, it is the second embodiment of the utility model, the protruding structure 24a is also flat plate structure, the included angle between adjacent protruding structure 24a is 10-170 °, the protruding structure 24a is divided into two groups, and the two groups of protruding structure 24a are arranged in a staggered manner along the length direction of the circuit board 2a.

[0032] As shown in FIG. 4, it is the third embodiment of the utility model, the protruding structure 24b is arc plate structure, the number of protruding structure 24b is 1-1000. The protruding structure 24b is arranged in a symmetrical manner with the center line of the circuit board 2b as the center.

[0033] As shown in Figure 5, it is the fourth embodiment of the utility model, the convex structure 24c is the combination of arc plate structure and arc block structure, the number of convex structure 24c is 1-1000. The convex structure 24c is symmetrically arranged with the center line of the circuit board 2c. In other embodiments, the convex structure can also be a combination of a flat plate structure, an arc plate structure and an arc block structure.

[0034] As shown in Figure 6, it is the fifth embodiment of the utility model, the arrangement of a plurality of convex structures 24d is a Tesla valve structure, the convex structure 24d is an arc block structure, specifically, the convex structure 24d includes a first convex part 241d, a second convex part 242d surrounding the first convex part 241d and a third convex part 243d surrounding the second convex part 242d, the first convex part 241d is located at the middle position of the circuit board 2d, the second convex part 242d is in the shape of a water droplet, and the third convex part 243d extends from the third circuit board 27d into the communication channel 23d. The convex structure 24d is symmetrically arranged with the center line of the circuit board 2d.

[0035] Compared with the related art, the utility model provides a kind of MEMS packaging structure, which includes shell, circuit board with the shell cover and form the containing space of MEMS chip and ASIC chip placed in the containing space, the MEMS chip includes diaphragm and the back plate spaced apart from the diaphragm, the MEMS chip is fixed to the circuit board, the circuit board includes the upper surface connected with the MEMS chip and the lower surface opposite to the upper surface, the circuit board is also provided with first sound hole extending from the lower surface to the upper surface and not passing through the upper surface, second sound hole extending from the upper surface to the lower surface and not passing through the lower surface, communication channel being located between the upper surface and the lower surface and communicating the first sound hole and the second sound hole, the MEMS chip covers the second sound hole, the projection of the first sound hole and the second sound hole along the diaphragm vibration direction does not overlap each other, a plurality of convex structures are provided in the communication channel, the convex structure makes the pressure of airflow entering from the first sound hole be 2-3.5 times of the pressure of airflow flowing from the second sound hole. The MEMS packaging structure of the utility model can effectively reduce the airflow after reaching the second sound hole, so that the airflow pressure reaching the diaphragm is reduced by 1 / 2-2 / 3 compared with the airflow pressure reaching the diaphragm in the prior art, thereby buffering the impact force of air pressure on the diaphragm of MEMS chip.

[0036] The above merely illustrates the embodiments of the present application, and it should be pointed out that, for those skilled in the art, improvements can be made without departing from the inventive concept, and these improvements are within the protection scope of the present application.

Claims

1. A MEMS package structure comprising a housing, a circuit board which forms a receiving space with the housing cover, and a MEMS chip and an ASIC chip disposed in the receiving space, the MEMS chip comprising a diaphragm and a back plate which is disposed in a spaced relationship with the diaphragm, the MEMS chip being fixed to the circuit board, the circuit board comprising an upper surface which is connected to the MEMS chip and a lower surface which is opposite to the upper surface, characterized in that: The circuit board is further provided with a first sound hole extending from the lower surface to the upper surface and not penetrating the upper surface, a second sound hole extending from the upper surface to the lower surface and not penetrating the lower surface, a communication channel provided between the upper surface and the lower surface and communicating the first sound hole and the second sound hole, the MEMS chip covering the second sound hole, projections provided in the communication channel, the projections causing the pressure of the airflow entering from the first sound hole to be 2-3.5 times the pressure of the airflow flowing out from the second sound hole.

2. The MEMS package structure of claim 1, wherein, The projections extend from the lower surface and do not contact the upper surface, or the projections extend from the upper surface and do not contact the lower surface.

3. The MEMS package structure of claim 1, wherein, The circuit board is a laminated circuit board, which comprises a first circuit board connected with the MEMS chip, a second circuit board provided in spaced relation to the first circuit board, and a third circuit board located between the first circuit board and the second circuit board, the third circuit board being a hollow ring structure, the second sound hole penetrating the first circuit board, and the first sound hole penetrating the second circuit board.

4. The MEMS package structure of claim 1, wherein, The arrangement of the projections is in a Tesla valve structure.

5. The MEMS package structure of claim 1, wherein, The projections cause the airflow entering from the first sound hole to reach the second sound hole along at least two different paths.

6. The MEMS package structure of claim 1, wherein, The airflow entering from the first sound hole produces turbulent flow after contacting the projections to reduce the pressure of the airflow.

7. The MEMS package structure of claim 6, wherein, The projections are flat plate structures, and the included angle between adjacent projections is 10-170°.

8. The MEMS package structure of claim 6, wherein, The projections are flat plate structures, and / or arc-shaped plate structures, and / or arc-shaped block structures.

9. The MEMS package structure of claim 6, wherein, The number of the projections is 1-1000.

10. The MEMS package structure of claim 1, wherein, The diaphragm is closer to the circuit board than the back plate.

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