CN212954301U

CN212954301U - MEMS device

Info

Publication number: CN212954301U
Application number: CN202021493844.1U
Authority: CN
Inventors: 梅嘉欣; 李�浩
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2021-04-13
Anticipated expiration: 2030-07-24

Abstract

The utility model provides a MEMS device has solved the problem of the increase of MEMS device size and the increase of the wiring degree of difficulty that leads to owing to add electric capacity in the MEMS device among the prior art. The MEMS device includes: the circuit board comprises a first surface, wherein a first wiring terminal is arranged on the first surface; the shell comprises a conductive path, and is arranged on the first surface to form a cavity with the circuit board; and the capacitor is positioned in the cavity and comprises a first pin and a second pin, the first pin is connected with the first wiring terminal, and the second pin is connected with the conductive path.

Description

MEMS device

Technical Field

The utility model relates to a Micro-Electro-Mechanical System (MEMS) technical field, concretely relates to MEMS device.

Background

In a MEMS device, a package structure generally includes a Circuit board and a housing on the Circuit board, a cavity is formed between the housing and the Circuit board, and a MEMS chip having a Specific function and an Application Specific Integrated Circuit (ASIC) corresponding to the MEMS chip are disposed in the cavity and supported by the Circuit board. Meanwhile, the package structure of the MEMS device often further includes some auxiliary components, such as a capacitor.

In order to package the capacitor into the package structure of the MEMS device, two predetermined pads are usually required to be disposed on the surface of the circuit board located in the cavity, and two pins of the capacitor are respectively connected to the two pads. The arrangement of the preset welding disc occupies the area of the circuit board, the miniaturization of products is adversely affected, and meanwhile, the wiring difficulty of the circuit board is improved.

SUMMERY OF THE UTILITY MODEL

In view of this, the embodiment of the present invention provides a MEMS device to solve the problem of the increase in size and the increase in wiring difficulty of the MEMS device caused by adding a capacitor in the MEMS device in the prior art.

The utility model provides a MEMS device, include: the circuit board comprises a first surface, wherein a first wiring terminal is arranged on the first surface; the shell comprises a conductive path, and is arranged on the first surface to form a cavity with the circuit board; and the capacitor is positioned in the cavity and comprises a first pin and a second pin, the first pin is connected with the first wiring terminal, and the second pin is connected with the conductive path.

In one embodiment, the first pin and the second pin of the capacitor are oppositely arranged.

In one embodiment, the housing includes a top wall parallel to the first surface, and the second leg of the capacitor is connected to the conductive path at the top wall.

In one embodiment, the capacitor rests on the first surface and the sidewall.

In one embodiment, the capacitor includes a first end and a second end disposed opposite to each other, the first pin is located at the first end, and the second pin is located at the second end. The circuit board comprises a first groove arranged on the first surface, and the first end is positioned in the first groove; and/or the housing includes a second recess directly opposite the first recess, the second end being located within the second recess.

In one embodiment, the device further comprises an ASIC chip positioned in the cavity, wherein the ASIC chip comprises a signal port which is electrically connected with the first pin of the capacitor; the inner wall of the shell is conductive, and the second pin of the capacitor is grounded through the inner wall of the shell.

In one embodiment, the signal port is connected to the first connection terminal by a metal wire.

In one embodiment, the first surface is further provided with a second connection terminal, and the signal port is connected to the second connection terminal through a metal wire; the first connection terminal and the second connection terminal are connected by a circuit wiring in the circuit board.

In one embodiment, the signal port includes any one of an input pin, an output pin, and a power pin.

In one embodiment, the housing is hermetically connected to the circuit board by a conductive material; the circuit board further comprises a second surface opposite to the first surface, and the second surface is provided with a grounding terminal; the conductive material is connected to circuit traces within the circuit board through metallized vias on the circuit board and to the ground terminals via the circuit traces.

In one embodiment, the device further comprises a sound hole for communicating the cavity and the atmosphere; the packaging structure further comprises a MEMS acoustic chip positioned in the cavity, and the MEMS acoustic chip is electrically connected with the ASIC chip.

According to the utility model provides a MEMS device, the second pin of electric capacity is connected with the electrically conductive route on the casing to draw the second pin outside the packaging structure of MEMS device through the casing. At this moment, only one first wiring terminal is needed to be arranged on the circuit board 11 to lead out the first pin of the capacitor to the outside of the packaging structure of the MEMS device, and for the two pins of the capacitor to be respectively led out to the outside of the packaging structure through two bonding pads on the circuit board, the number of the first wiring terminals needed to be arranged on the circuit board is reduced, so that the size of the circuit board is reduced, and further, the size of the MEMS device is reduced. Meanwhile, the wiring in the circuit board needs to bypass the first wiring terminals on the circuit board, so that the wiring difficulty of the circuit board can be further reduced when the number of the first wiring terminals is reduced.

Drawings

Fig. 1 is a schematic structural diagram of a MEMS device according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a MEMS device according to another embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a MEMS device according to another embodiment of the present invention.

Fig. 4 is a schematic side view of a packaging structure of a microphone according to an embodiment of the present invention.

Fig. 5 is a schematic top view of the package structure of the microphone shown in fig. 4.

Fig. 6 is a schematic circuit diagram of the microphone shown in fig. 4.

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 work belong to the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of a MEMS device according to an embodiment of the present invention. As shown in fig. 1, the MEMS device 10 includes a circuit board 11, a case 12, and a capacitor 13. The circuit board 11 includes a first surface S₁First surface S₁On which a first connection terminal 111 is provided. The housing 12 includes a conductive path, and the housing 12 is disposed on the first surface S₁And a cavity Q is formed between the circuit board 11 and the cavity. The capacitor 13 is located in the cavity Q, the capacitor 13 includes a first pin 131 and a second pin 132, the first pin 131 is connected to the first connection terminal 111, and the second pin 132 is connected to the conductive path on the housing 12.

The circuit board 11 and the housing 12 together constitute a package structure of the MEMS device. The conductive path on the housing 12 is used to lead the second pin 132 of the capacitor 13 out of the package structure, for example, the conductive path forms a terminal on the outer surface of the housing 12; as another example, the conductive path is through gold on the circuit board 11The belonged via holes are connected with the wiring inside the circuit board 11, and further, the wiring is arranged on the first surface S of the circuit board 11₁The opposite second surface S₂Forming a bonding pad. The first connection terminal 111 on the circuit board 11 is used for leading out the first pin 131 of the capacitor 13 to the outside of the package structure, for example, the first connection terminal 111 is wired on the second surface S of the circuit board 11 through the inside of the circuit board 11₂Forming a bonding pad.

The conductive path may be a line formed of a conductive material or may be the housing 12 itself. The conductive path is the housing itself, which means that the housing 12 itself is conductive, such as a metal housing, in which case the entire housing 12 acts as a conductive path and the second pin 132 is directly connected to the housing 12.

According to the MEMS device provided in the present embodiment, when the capacitor 13 is packaged in the package structure of the MEMS device, one pin (i.e., the second pin 132) of the capacitor 13 is led out of the package structure through the case 12. At this time, only one first connection terminal 111 (for example, a pad) needs to be arranged on the circuit board 11 to lead out the other pin (i.e., the first pin 131) of the capacitor 13 to the outside of the package structure, and compared with the case that the two pins of the capacitor 13 are respectively led out to the outside of the package structure through two pads on the circuit board 11, the number of the first connection terminals 111 that need to be arranged on the circuit board 11 is reduced, so that the size of the circuit board 11 is reduced, and the size of the MEMS device is further reduced. Meanwhile, since the wiring in the circuit board 11 needs to bypass the first connection terminals on the circuit board 11, when the number of the first connection terminals is reduced, the difficulty of wiring the circuit board 11 can be further reduced.

In one embodiment, as shown in fig. 1, the first pin 131 and the second pin 132 of the capacitor 13 are oppositely disposed. That is, for a packaged capacitor 13, the first lead 131 and the second lead 132 are respectively located at two opposite sides of the package structure of the capacitor 13, i.e. the connection line L of the first lead 131 and the second lead 132 on the package structure of the capacitor 13 passes through the package structure of the capacitor 13.

In a preferred embodiment, the connection line L of the first pin 131 and the second pin 132 on the package structure of the capacitor 13 passes through the center of gravity of the capacitor 13.

For the MEMS device 10 shown in fig. 1, when the capacitor is packaged in the package structure of the MEMS device, the first pin 131 of the capacitor 13 is connected to the first connection terminal 111 on the circuit board 11, and the second pin 132 is connected to the housing 12. In this case, the first pin 131 and the second pin 132 are the stress points of the fixed capacitor 13. According to the MEMS device 10 provided in this embodiment, by disposing the two force points of the capacitor 13 oppositely, i.e. disposing the first pin 131 and the second pin 132 oppositely, the force can be balanced, and the capacitor can be secured more firmly.

In one embodiment, as shown in FIG. 1, the housing 12 includes a first surface S₁Parallel to the top wall 121, the second leg 132 of the capacitor 13 is connected to the conductive path at the top wall 121, i.e. the second leg 132 of the capacitor 13 is connected to the conductive path at the top wall 121. In this case, it is equivalent to reversely packaging the capacitor 13 in the MEMS device 10, thereby providing a new packaging form of the capacitor.

Fig. 2 is a schematic structural diagram of a MEMS device according to another embodiment of the present invention. The MEMS device 20 shown in fig. 2 differs from the MEMS device 10 shown in fig. 1 only in that, in the present embodiment, the housing 12 further comprises a side wall 122 in addition to the top wall 121, and the second pin 232 of the capacitor 23 is connected to the conductive path at the side wall 122, i.e. the second pin 232 of the capacitor 23 is connected to the conductive path at the side wall 122.

In the present embodiment, the capacitor 23 is leant on the first surface S of the circuit board 11₁And the side wall 122 of the housing 12, i.e., the capacitor 23 and the first surface S of the circuit board 11, respectively₁Is in contact with the side wall 122 of the housing 12 and is thereby exposed to the first surface S₁And support for the side walls 122.

It should be understood that although the second leg 232 of the capacitor 23 in fig. 2 is connected to the conductive path at the sidewall 122 of the housing 12, it is merely exemplary. The location of the capacitor 23 and the location of the second pin 232 on the capacitor 23 can be properly arranged so that the second pin 232 is connected to the conductive path at the top wall 121 of the housing 12. At the same time, due to the first surface S₁And a support for the side wall 122, in which case the second one may be arbitrarily arrangedThe positions of the first pin 131 and the second pin 132 do not need to be considered in terms of the force balance between the first pin 131 and the second pin 132.

According to the MEMS device 20 provided by the embodiment, the first surface S of the circuit board 11₁And/or the side wall 122 of the housing 12 may provide support for the capacitor, avoiding the entire weight of the capacitor 23 from concentrating on the first leg 131 and/or the second leg 132, further ensuring that the capacitor is more securely held.

Fig. 3 is a schematic structural diagram of a MEMS device according to another embodiment of the present invention. The MEMS device 30 shown in fig. 3 differs from the MEMS device 10 shown in fig. 1 only in that the capacitor 33 includes a first end a and a second end B disposed opposite to each other, the first pin 331 is located at the first end a, and the second pin 332 is located at the second end B. The circuit board 11 includes a first surface S₁First end a is located within first groove 1101. The housing 12 includes a second recess 1102 opposite the first recess 1101, and the second end B is located within the second recess 1102.

In this case, the first connection terminal 111 is disposed at the bottom of the first groove 1101 to be electrically connected to the first pin 331 of the capacitor 33. A conductive path on the housing 12 passes through the bottom of the second recess 1102 to electrically connect with the second pin 332 of the capacitor 33.

It should be understood that the first groove 1101 on the circuit board 11 and the second groove 1102 on the housing 12 may be separately provided, for example, only the first groove 1101 on the circuit board 11 or only the second groove 1102 on the housing 12.

According to the MEMS device 30 provided in the present embodiment, the capacitor 33 is fixed by providing a recess on the circuit board 11 and/or the housing 12, so that the capacitor is more firmly fixed.

Microphones are an important branch of MEMS devices. During the use process of the microphone, external interference is extremely easily coupled to the input/output interface of the microphone, so that the capacitance can be connected in parallel to the input/output interface of the microphone to filter out the introduced interference noise. The following describes a packaging structure of a microphone having a capacitor structure in a MEMS device provided in any one of the above embodiments with reference to the accompanying drawings.

Fig. 4 is a schematic side view of a packaging structure of a microphone according to an embodiment of the present invention. Fig. 5 is a schematic top view of the package structure of the microphone shown in fig. 4. Fig. 6 is a schematic circuit diagram of the microphone shown in fig. 4. Referring to fig. 4, 5 and 6, the microphone 40 is based on the MEMS device 10 shown in fig. 1, and further includes an ASIC chip 14 located in the cavity Q, a MEMS acoustic chip 15 electrically connected to the ASIC chip 14, and an acoustic hole 16 communicating the cavity Q and the atmosphere, as shown in fig. 4, the acoustic hole 16 may be opened on the circuit board 11 or on the housing 12. Specifically, the ASIC chip 14 includes a plurality of signal ports, such as an input pin Vin, a Bias voltage pin Bias, a power supply pin Vdd, a ground pin GND, and an output pin Vout. Two electrodes of the MEMS acoustic chip 15 are connected to the input pin Vin and the Bias voltage pin Bias, respectively.

During the use of the microphone 40, external sound enters the cavity Q through the sound hole 16, the MEMS acoustic chip 15 converts the sound signal into an electrical signal, and the electrical signal is amplified by the ASIC chip and passes through the second surface S of the circuit board 11₂The upper wiring terminals are led out of the packaging structure.

In the present embodiment, at least a portion of the signal ports of the ASIC chip 14 may introduce external interference signals, such as the input pin Vin, the power pin Vdd, or the output pin Vout. For such pins, by connecting capacitors in parallel with the pins, noise introduced by the corresponding pins can be filtered out. Taking the output pin Vout as an example, the output pin Vout is electrically connected to the first pin 131 of the capacitor 13. The inner wall of the housing 12 is conductive, for example, the housing itself is made of metal, or a layer of metal is plated on the inner wall of the insulating housing, in which case, the entire housing 12 serves as a conductive path and can function as an electromagnetic shield. The second pin 132 of the capacitor 13 is grounded through the inner wall of the housing 12. Specifically, the electrical connection between the output pin Vout and the first pin 131 of the capacitor 13 may be achieved in the following two ways. For example, referring to fig. 4 and 5, the first surface S of the circuit board 11₁A second connection terminal 112 is further provided thereon, and the output pin Vout is connected to the second connection terminal 112 through a metal wire. A first connection terminal 111 and a second connection terminalThe connection terminals 112 are connected by circuit wiring in the circuit board 11. For another example, the output pin Vout is connected to the first connection terminal 111 through a metal wire. In this way, the first pin 131 corresponding to the output pin Vout and the capacitor 13 share the same connection terminal, so that the size of the circuit board can be further saved.

The grounding of the second pin 132 of the capacitor 13 through the housing 12 can be achieved as follows. The housing 12 is hermetically connected to the circuit board 11 through a conductive material. Second surface S of circuit board 11₂Provided with a ground terminal GND'. The conductive material is connected to the circuit wiring of the circuit board 11 through the metalized via on the circuit board 11 and is connected to the ground terminal GND' via the circuit wiring.

It should be understood that the present embodiment only takes the case that the output pin Vout is connected in parallel with one capacitor 13, and according to actual needs, the output pin Vout may also be connected in parallel with a plurality of capacitors, or at least one of the input pin Vin, the power supply pin Vdd, and the output pin Vout may be connected in parallel with one or more capacitors, respectively. Moreover, the capacitor 13 may adopt the package structure provided in any of the above embodiments, for example, the package structure shown in fig. 1, fig. 2, or fig. 3. Meanwhile, the present embodiment only uses a microphone as an example, and the package structure of the capacitor provided by the present invention can also be applied to other MEMS devices.

The foregoing description has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit embodiments of the application to the form disclosed herein. While a number of example aspects and embodiments have been discussed above, those of skill in the art will recognize certain variations, modifications, alterations, additions and sub-combinations thereof.

Claims

1. A MEMS device, comprising:

the circuit board comprises a first surface, wherein a first wiring terminal is arranged on the first surface;

a housing including a conductive path, the housing disposed on the first surface forming a cavity with the circuit board; and

the capacitor is positioned in the cavity and comprises a first pin and a second pin, the first pin is connected with the first wiring terminal, and the second pin is connected with the conductive path.

2. The MEMS device of claim 1, wherein the first pin and the second pin of the capacitor are oppositely disposed.

3. The MEMS device of claim 1 or 2, wherein the housing includes a top wall parallel to the first surface, the second leg of the capacitor being connected to the conductive via at the top wall.

4. The MEMS device of claim 1 or 2, wherein the capacitance rests on the first surface and a sidewall of the housing.

5. The MEMS device of claim 1 or 2, wherein the capacitor includes first and second oppositely disposed ends, the first pin being located at the first end and the second pin being located at the second end;

the circuit board comprises a first groove arranged on the first surface, and the first end is positioned in the first groove; and/or

The shell comprises a second groove opposite to the first groove, and the second end is located in the second groove.

6. The MEMS device of claim 1 or 2, further comprising an ASIC chip located within the cavity, the ASIC chip including a signal port, the signal port being electrically connected to the first pin of the capacitor; the inner wall of the shell is conductive, and the second pin of the capacitor is grounded through the inner wall of the shell.

7. The MEMS device of claim 6, wherein the signal port is connected to the first connection terminal by a metal wire.

8. The MEMS device of claim 6, wherein a second connection terminal is further provided on the first surface, the signal port being connected to the second connection terminal by a metal wire; the first connection terminal and the second connection terminal are connected by a circuit wiring in the circuit board.

9. The MEMS device of claim 6, wherein the signal port comprises any one of an input pin, an output pin, a power pin.

10. The MEMS device, as recited in claim 6, wherein the housing is hermetically connected to the circuit board by a conductive material; the circuit board further comprises a second surface opposite to the first surface, and a grounding terminal is arranged on the second surface; the conductive material is connected to circuit traces within the circuit board through the metallized vias on the circuit board and to the ground terminal via the circuit traces.

11. The MEMS device of claim 6, further comprising an acoustic port communicating the cavity with the atmosphere; the MEMS device further comprises a MEMS acoustic chip located in the cavity, and the MEMS acoustic chip is electrically connected with the ASIC chip.