CN215647356U

CN215647356U - Packaging structure, microphone and terminal of micro-electro-mechanical system

Info

Publication number: CN215647356U
Application number: CN202122338481.5U
Authority: CN
Inventors: 杨玉婷; 张敏; 梅嘉欣; 张永强
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2021-09-26
Filing date: 2021-09-26
Publication date: 2022-01-25
Anticipated expiration: 2031-09-26

Abstract

The application discloses micro electro mechanical system's packaging structure, microphone and terminal, this packaging structure includes: a substrate; the inner shell is fixed on the substrate and forms an accommodating cavity with the substrate; an outer housing fixed on the substrate and surrounding the inner housing, wherein a gap is formed between the inner housing and the outer housing; the bonding layer is positioned between the inner shell and the substrate and between the outer shell and the substrate, and the part between the inner shell and the substrate is not connected by the bonding layer, so that one or more openings are formed between the inner shell and the substrate, and each opening is communicated with the gap and the accommodating cavity; and one or more leads located on the substrate corresponding to the accommodating cavity, wherein at least one lead is partially located in the opening. This packaging structure has reduced because the gas expansion in the clearance leads to the casing to collapse the risk of opening through setting up the opening in intercommunication holding chamber and clearance, still extends the lead wire to the opening for the lead wire stretches open-ended one end and keeps away from the inside chip of holding chamber, has reduced the interference of signal of telecommunication to the chip.

Description

Packaging structure, microphone and terminal of micro-electro-mechanical system

Technical Field

The present application relates to the field of semiconductor device manufacturing, and more particularly, to packaging structures, microphones, and terminals for microelectromechanical systems.

Background

A microphone manufactured based on Micro Electro Mechanical Systems (MEMS) is called a MEMS microphone, and generally includes a MEMS sensor chip and an Application Specific Integrated Circuit (ASIC) chip electrically connected to the MEMS sensor chip, and during a process of packaging the MEMS microphone, the MEMS sensor chip and the ASIC chip need to be connected to a substrate, and then a package housing is formed by the package and the substrate to seal the MEMS sensor chip and the ASIC chip.

The MEMS microphone packaging part commonly used at present is of a single-layer shell structure, and in a strong electromagnetic field, due to the fact that the single-layer shell is insufficient in electromagnetic shielding capacity, the MEMS microphone is interfered by electromagnetic signals, noise is generated, and sound signals are affected. If a completely closed double-shell structure is adopted, the gas between the double shells may cause the shell to burst due to thermal expansion, so that the welding of the shell is poor, and the acoustic performance of the MEMS microphone is affected.

Accordingly, it is desirable to provide an improved packaging structure for a MEMS to improve the performance of MEMS microphones.

SUMMERY OF THE UTILITY MODEL

In view of this, the present invention provides an improved package structure of a micro electro mechanical system, a microphone and a terminal, in which an opening communicating an accommodating cavity and a gap is provided, so as to reduce the risk of the housing being collapsed due to the expansion of the gas in the gap, and a lead is extended toward the opening, so that one end of the lead extending toward the opening is far away from a chip inside the accommodating cavity, thereby reducing the interference of an electrical signal to the chip.

According to a first aspect of embodiments of the present invention, there is provided a package structure of a micro electro mechanical system, including: a substrate; the inner shell is fixed on the substrate, forms an accommodating cavity with the substrate and is used for accommodating the MEMS sensor chip and the signal processing chip; an outer housing fixed to the substrate and surrounding the inner housing, wherein a gap is formed between the inner housing and the outer housing; the bonding layer is positioned between the inner shell and the base plate and between the outer shell and the base plate, and the part between the inner shell and the base plate is not connected by the bonding layer, so that one or more openings are formed between the inner shell and the base plate, and each opening is communicated with the gap and the accommodating cavity; and one or more leads positioned on the substrate and corresponding to the accommodating cavity, wherein part of at least one lead is positioned in the opening.

Optionally, the adhesive layer further includes a blocking layer, located on the substrate, corresponding to the opening in position to block the adhesive layer from reflowing to close the opening.

Optionally, the barrier layer covers at least a portion of the lead located in the opening.

Optionally, the substrate includes an inner bonding ring on which the adhesive layer is located, wherein the inner bonding ring is broken at a portion corresponding to the lead in the opening to separate the lead from the inner bonding ring.

Optionally, the barrier layer also covers a partial region of the inner solder ring where the adhesive layer on the inner solder ring is broken.

Optionally, the surface of the substrate has a chip carrying area and a metal foil on the chip carrying area, wherein the barrier layer further covers the metal foil.

Optionally, the substrate further includes an outer solder ring surrounding the inner solder ring, and the adhesive layer is further located on the outer solder ring to connect the outer solder ring and the outer casing.

Optionally, the substrate further includes a wire bonding region, the wire bonding region corresponds to the accommodating cavity, and in the accommodating cavity, the barrier layer further covers the surface of the substrate and exposes the wire bonding region.

Optionally, at least two of the plurality of leads extend into the same or different openings.

Optionally, at least one of the leads extends into the gap through the opening.

Optionally, the inner housing and the outer housing are not in contact with each other.

Optionally, the inner shell and the outer shell are both metal shells.

According to a second aspect of the embodiments of the present invention, there is provided a microphone including the package structure as described above.

According to a third aspect of embodiments of the present invention, there is provided a terminal comprising the microphone as described above.

According to the packaging structure of the micro-electro-mechanical system, the microphone and the terminal provided by the embodiment of the utility model, the radiation resistance and the electromagnetic shielding effect are improved through the gap between the double-layer shell and the double-layer shell. And make the part between interior casing and the base plate can not connected by the bonding layer for have the opening between interior casing and the base plate, thereby let clearance and holding chamber intercommunication between the double shell, not only make the gas in the clearance can circulate, reduced because the gas inflation in the clearance leads to the risk that the casing bursts open, but also can increase packaging structure internal environment's cavity volume, improved the sensitivity and the SNR of microphone, and then promoted the performance of product.

Furthermore, the part of at least one lead is arranged in the opening, and the multiplexing opening expands the wiring space, so that one end of the lead extending to the opening is far away from the MEMS sensor chip and the signal processing chip, and the interference of an electric signal to the chip is reduced.

The blocking layer is arranged on the surface of the substrate and corresponds to the opening, so that the adhesive layer can be effectively prevented from reflowing to seal the opening, and the smoothness of the opening is further ensured.

Through covering the part that the lead wire passes through the opening with the barrier layer, further with adhesive linkage and lead wire isolation, reduced because of the adhesive linkage makes the risk of inner casing and lead wire short circuit.

Through set up inside and outside weld ring on the base plate to make inside and outside casing pass through the adhesive linkage and inside and outside weld ring is fixed, and with partial blocking layer setting on the subregion of inside weld ring, can effectually prevent this subregion by the adhesive linkage adheres to, and then formed new gas circuit opening between inside casing and weld ring, further reduced because the gas expansion in the clearance leads to the casing to collapse the risk of opening.

The metal foil is arranged in the chip bearing area of the substrate, so that the electromagnetic shielding performance of a product is further enhanced, the barrier layer covers the metal foil, the chip is isolated from the metal foil, and the influence of the metal foil on the chip is reduced.

Through all setting up interior casing and shell body into the metal casing that electromagnetic shielding performance is good, and interior casing and shell body contactless, can increase the volume in clearance, the air in the clearance is transmission medium, and more transmission medium can further promote the electromagnetic shielding performance of microphone.

Therefore, the packaging structure of the micro-electro-mechanical system, the microphone and the terminal provided by the utility model can greatly improve the performance of products.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description only relate to some embodiments of the present application and are not limiting on the present application.

Fig. 1 shows a schematic structural view of a micro-electromechanical system according to a first embodiment of the present invention.

FIG. 2 illustrates a top view of the front side of a substrate in a MEMS device in accordance with a first embodiment of the present invention.

Fig. 3 shows a cross-sectional view along line AA in fig. 2.

FIGS. 4 and 5 are top views of the layout of inner bond rings and leads in a MEMS device in accordance with a first embodiment of the present invention.

FIG. 6 illustrates a top view of a barrier layer in a MEMS according to a first embodiment of the present invention.

Fig. 7 shows a cross-sectional view along line AA in fig. 6.

FIG. 8 illustrates a top view of a barrier layer in a MEMS according to a second embodiment of the present invention.

Fig. 9 shows a cross-sectional view along line AA in fig. 8.

FIGS. 10 and 11 illustrate top front views of a MEMS in partial packaging steps according to embodiments of the present invention.

Fig. 12 shows a cross-sectional view along line AA in fig. 11.

Fig. 13 shows a cross-sectional view taken along line BB in fig. 11.

FIG. 14 illustrates a top view of a barrier layer in a MEMS according to a third embodiment of the present invention.

Detailed Description

The utility model will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. In addition, certain well known components may not be shown. For simplicity, the semiconductor structure obtained after several steps can be described in one figure.

It will be understood that when a layer or region is referred to as being "on" or "over" another layer or region in describing the structure of the device, it can be directly on the other layer or region or intervening layers or regions may also be present. And, if the device is turned over, that layer, region, or regions would be "under" or "beneath" another layer, region, or regions.

If for the purpose of describing the situation directly on another layer, another area, the expressions "directly on … …" or "on … … and adjacent thereto" will be used herein.

In the following description, numerous specific details of the utility model, such as structure, materials, dimensions, processing techniques and techniques of the devices are described in order to provide a more thorough understanding of the utility model. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.

The present invention may be embodied in various forms, some examples of which are described below.

As shown in fig. 1, a micro-electromechanical system according to a first embodiment of the present invention includes: the MEMS sensor chip 500 is, for example, a microphone chip, and the signal processing chip 600 is, for example, an ASIC chip, and the MEMS sensor chip 500 is, for example, a MEMS sensor chip. The package structure includes: a substrate 100, an adhesive layer 400, an inner housing 700, and an outer housing 800, wherein the substrate 100 is implemented by, for example, a PCB. The inner housing 700 is fixed on the substrate 100 by the adhesive layer 400, and forms the accommodating chamber 10 with the substrate 100. The electrically connected MEMS sensor chip 500 and the signal processing chip 600 are located in the accommodating chamber 10. The outer case 800 is fixed to the substrate 100 by the adhesive layer 400, the outer case 800 surrounds the inner case 700, and a gap 20 is provided between the inner case 700 and the outer case 800. At least a portion of the inner housing 700 and the substrate 100 are not connected by the adhesive layer 400, so that one or more openings 401 are formed between the inner housing 700 and the substrate 100, and the openings 401 communicate the gap 20 and the accommodating chamber 10. In the present embodiment, the sound hole 101 penetrates through the substrate 100 for communicating the back cavity of the MEMS sensor chip 500 with the external environment of the package structure.

In the present embodiment, the substrate 100 includes an inner solder ring 211 and an outer solder ring 212 separated from each other, and the outer solder ring 212 surrounds the inner solder ring 211, wherein the material of the adhesive layer 400 is solder paste, and the solder paste is respectively located on the inner solder ring 211 and the outer solder ring 212. The inner case 700 is fixed to the inner solder ring 211 by solder paste, and the outer case 800 is fixed to the outer solder ring 212 by solder paste. One skilled in the art can also set the material of the adhesive layer 400, such as silver paste, as desired. Of course, in some other embodiments, one skilled in the art may omit the solder ring as desired.

Further, interior casing 700 and shell body 800 do not contact each other, and interior casing 700 and shell body 800 are metal casing, and two-layer metal shell can electrically connect, also can set up mutually independent pad at the back of base plate 100 and electrically connect interior casing 700 and shell body 800 respectively to play the effect that promotes product electromagnetic shield performance. Of course, other arrangements of the materials of the inner and

outer housings

700, 800 are possible to those skilled in the art.

As shown in fig. 2 and 3, in the present embodiment, the inner welding ring 211 has a plurality of fractures 211 a. The surface of the substrate 100 has at least one lead, and in some specific embodiments, the surface of the substrate 100 has a first lead 111, a second lead 112 and a third lead 113 that are separated from each other, wherein the first lead 111 and the second lead 112 are signal source leads such as VDD, Data, Clock, etc., and the third lead 113 is a GND lead, for example. The substrate 100 may further include other leads besides the first lead 111 and the second lead 112, which are not listed here, and the correspondence relationship between the first lead 111 and the second lead 112 and the opening is also applicable to other leads. The surface of the substrate 100 further has a first chip carrying area 121 and a second chip carrying area 122 for carrying the MEMS sensor chip 500 and the signal processing chip 600, respectively, wherein the sound hole 101 is located in the first chip carrying area 121. In some preferred embodiments, the second chip carrying region 122 is laid with a metal foil, such as a copper foil, but those skilled in the art may also perform other arrangements on the position of the metal foil as needed, such as also laying on the first chip carrying region 121, or laying the metal foil on the front surface of the whole substrate 100, but ensuring that the metal foil is electrically isolated from other polarity (e.g., VDD, Data, Clock, etc.) lines on the substrate 100.

In some specific embodiments, the inner weld ring 211 and the outer weld ring 212 are both rectangular rings. The first chip carrying region 121 is close to one of the short sides of the inner bonding ring 211, and the second chip carrying region 122 is adjacent to the first chip carrying region 121. The inner welding ring 211 has two breaks 211a respectively located on two long sides of the inner welding ring 211 and both near the other short side of the inner welding ring 211. The first and

second leads

111 and 112 extend from the inner side of the inner bonding ring 211 into different fractures 211a, respectively, and the inner bonding ring 211 is separated from the first and

second leads

111 and 112, respectively. Further, the first lead 111 and the second lead 112 have metal conductive holes at one ends of the fracture 211a, and the first lead 111 and the second lead 112 are electrically connected to the pads on the back surface of the substrate 100 through the metal conductive holes. The third lead 113 is located inside the inner bonding ring 211 and between the first lead 111 and the second lead 112. Those skilled in the art may make other arrangements of the shapes of inner and outer bonding rings 211 and 212, the locations of first and second

chip carrying regions

121 and 122 and break 211a, the routing of first, second and

third leads

111, 112 and 113 as needed, for example, at least one of first and

second leads

111 and 112 may extend through break 211a between inner and outer bonding rings 211 and 212 and be spaced apart from outer bonding ring 212, or one of first and

second leads

111 and 112 may be disposed completely inside inner bonding ring 211, and so on.

In other embodiments, as shown in fig. 4, the two breaks 211a of the inner solder ring 211 are located on the short side of the inner solder ring 211 on the side away from the sound hole 101. The first and

second leads

111 and 112 extend from the inner side of the inner bonding ring 211 to between the inner bonding ring 211 and the outer bonding ring 212 through different breaks 211a, respectively. One skilled in the art can also merge two fractures 211a as needed so that the first lead 111 and the second lead 112 pass through the same fracture 211 a. In other embodiments, as shown in FIG. 5, the number of interruptions 211a is more than two.

As shown in fig. 6 and 7, in some preferred embodiments, the package structure further includes a barrier layer 300. The surface of the substrate 100 has a wire bonding region 120 surrounding connection ends of the first lead 111, the second lead 112, and the third lead 113. In some specific embodiments, the material of the barrier layer 300, including but not limited to ink, is coated on the surface of the substrate 100 and filled in the fracture of the inner solder ring 211 to cover the ends of the first and

second leads

111 and 112 extending to the fracture. The barrier layer 300 is further filled inside the inner solder ring 211 to cover the metal foil and expose the sound hole 101 and the bonding pad 120. One skilled in the art may also fill only the barrier layer 300 in the break in the inner solder ring 211 as desired. In other embodiments, as shown in fig. 8 and 9, the barrier layer 300 may be disposed on a portion of the inner solder ring 211 at intervals.

As shown in fig. 10, in the step of packaging the MEMS, for example, the MEMS sensor chip 500 is first fixed on the first chip carrying region 121, and the signal processing chip 600 is first fixed on the second chip carrying region 122, wherein the metal foil and the chip are separated by the barrier layer 300. Then, for example, the MEMS sensor chip 500 and the signal processing chip 600 are electrically connected through a wire bonding process, and the signal processing chip 600 is electrically connected to the first lead 111, the second lead 112 and the third lead 113, respectively.

Further, an adhesive layer 400 is coated on the inner and outer weld rings 211 and 212, as shown in fig. 11 to 13. Wherein, when adhesive linkage 400 is tin cream or silver thick liquid, barrier layer 300 is when printing ink, printing ink is equivalent to the solder resist, because printing ink and tin cream, silver thick liquid are not moist completely, and printing ink has good heat resistance and insulating nature, in the position that has barrier layer 300, barrier layer 300 can prevent adhesive linkage 400 backward flow to cover, when interior casing 700 is connected through adhesive linkage 400 and interior solder ring 211, can form opening 401 between interior casing 700 and the base plate 100, thereby communicate holding chamber 10 and clearance 20. In some other embodiments, if no barrier layer is disposed, a way of dotting solder paste, silver paste, or other bonding materials may be adopted to avoid extending the first lead 111 and the second lead 112, when the inner housing 700 is connected to the inner bonding ring 211 through the bonding layer 400, an opening 401 communicating the accommodating cavity 10 and the gap 20 is also formed between the inner housing 700 and the substrate 100, and the first lead 111 and the second lead 112 have ends extending to the opening 401.

As shown in fig. 14, the difference from the first and second embodiments is that in the mems according to the third embodiment of the present invention, the inner solder ring 211 is closed, which saves the break structure. Only by coating the barrier layer 300 on a partial area of the inner weld ring 211, the coverage of the adhesive layer 400 is avoided, so that an opening is formed between the inner case and the substrate 100. The first lead 111 and the second lead 112 are both located inside the inner bonding ring 211, due to size limitation, the routing of the first lead 111 and the second lead 112 can only extend toward the signal processing chip 600, after the packaging is completed, a part of the first lead 111 and the second lead 112 will be pressed below the signal processing chip 600, if more routing is provided on the substrate 100, the first lead 111 and the second lead 112 will even extend between the MEMS sensor chip 500 and the signal processing chip 600, and the electrical signals transmitted through the first lead 111 and the second lead 112 will cause interference to the MEMS sensor chip 500 and the signal processing chip 600.

Compared with the third embodiment, the opening 401 for accommodating the first lead 111 and the second lead 112 in the first and second embodiments not only can serve to communicate the accommodating cavity 10 with the gap 20, thereby reducing the risk of shell explosion, but also can enlarge the routing space of the internal polar circuits (the first lead 111 and the second lead 112), and particularly for a small-sized micro-electro-mechanical system, the larger routing space can avoid the influence on the product performance due to the limitation of the precision of the packaging equipment, so that the design size has a larger margin, and the process feasibility is higher. In addition, the polar circuit extends towards the opening 401, so that signal sources such as VDD, Data, CLK and the like can be far away from the MEMS sensor chip 500 and the signal processing chip 600, the influence of various electric signals on the MEMS sensor chip 500 and the signal processing chip 600 is reduced, and the performance such as the signal-to-noise ratio of products of the micro-electro-mechanical system is improved. Of course, the embodiments of the present invention are not limited thereto, and those skilled in the art may omit the inner solder ring and the outer solder ring as needed, and leave an opening between the inner solder ring and the substrate for allowing the polarity line to pass through.

In the above description, the technical details of patterning, etching, and the like of each layer are not described in detail. It will be appreciated by those skilled in the art that layers, regions, etc. of the desired shape may be formed by various technical means. In addition, in order to form the same structure, those skilled in the art can also design a method which is not exactly the same as the method described above. In addition, although the embodiments are described separately above, this does not mean that the measures in the embodiments cannot be used in advantageous combination.

The embodiments of the present invention have been described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The scope of the utility model is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be devised by those skilled in the art without departing from the scope of the utility model, and these alternatives and modifications are intended to fall within the scope of the utility model.

Claims

1. A mems package structure, comprising:

a substrate;

the inner shell is fixed on the substrate, forms an accommodating cavity with the substrate and is used for accommodating the MEMS sensor chip and the signal processing chip;

an outer housing fixed to the substrate and surrounding the inner housing, wherein a gap is formed between the inner housing and the outer housing;

the bonding layer is positioned between the inner shell and the base plate and between the outer shell and the base plate, and the part between the inner shell and the base plate is not connected by the bonding layer, so that one or more openings are formed between the inner shell and the base plate, and each opening is communicated with the gap and the accommodating cavity; and

one or more leads located on the substrate corresponding to the accommodating cavity,

wherein a portion of at least one of the leads is located in the opening.

2. The package structure of claim 1, further comprising a barrier layer on the substrate corresponding to the opening to block the adhesive layer from reflowing to close the opening.

3. The package structure of claim 2, wherein the barrier layer covers at least a portion of the leads located in the openings.

4. The package structure of claim 3, wherein the substrate includes an inner solder ring, the adhesive layer is on the inner solder ring,

wherein the inner bonding ring is broken at a portion corresponding to the lead in the opening to separate the lead from the inner bonding ring.

5. The package structure of claim 4, wherein the barrier layer further covers a partial area of the inner solder ring where the adhesive layer on the inner solder ring is broken.

6. The package structure of claim 3, wherein the surface of the substrate has a chip-carrying area and a metal foil on the chip-carrying area,

wherein the barrier layer also covers the metal foil.

7. The package structure of claim 4, wherein the substrate further comprises an outer solder ring surrounding the inner solder ring, and wherein the adhesive layer is further on the outer solder ring to connect the outer solder ring to the outer casing.

8. The package structure of claim 4, wherein the substrate further comprises a wire bonding area corresponding to the receiving cavity,

in the accommodating cavity, the barrier layer also covers the surface of the substrate and exposes the wire bonding area.

9. The package structure according to any one of claims 1 to 8, wherein at least two of the plurality of leads extend into the same or different openings.

10. The package structure of any of claims 1-8, wherein at least one of the leads extends into the gap through the opening.

11. The encapsulation structure of any one of claims 1 to 8, wherein the inner shell and the outer shell are not in contact with each other.

12. The encapsulation structure of any one of claims 1 to 8, wherein the inner shell and the outer shell are both metal shells.

13. A microphone comprising a package structure as claimed in any one of claims 1 to 12.

14. A terminal, characterized in that it comprises a microphone according to claim 13.