CN215326927U

CN215326927U - MEMS sensor and packaging structure thereof

Info

Publication number: CN215326927U
Application number: CN202120465540.2U
Authority: CN
Inventors: 曹诚; 陈为波
Original assignee: Dongguan Ruiqin Electronics Co ltd
Current assignee: Dongguan Ruiqin Electronics Co ltd
Priority date: 2021-03-04
Filing date: 2021-03-04
Publication date: 2021-12-28
Anticipated expiration: 2031-03-04

Abstract

The application discloses MEMS sensor and packaging structure thereof, this MEMS sensor includes: a packaging structure; and the micro-electromechanical structure chip and the signal processing chip which are electrically connected, wherein the micro-electromechanical structure chip and the signal processing chip are both positioned in the cavity of the packaging structure, and the packaging structure comprises: the base plate, have open-ended interior casing and shell body, interior casing and base plate fixed connection to form the cavity with the base plate, the shell body surrounds interior casing, and shelters from the opening, and the signal processing chip is fixed on the base plate, and the open-ended position corresponds with the signal processing chip, and micro electromechanical structure chip staggers each other with the opening. Because the opening of the inner shell of the MEMS sensor corresponds to the signal processing chip, and the opening does not expose the MEMS chip, the influence and damage to the MEMS chip are reduced under the condition that the signal processing chip is processed through the opening.

Description

MEMS sensor and packaging structure thereof

Technical Field

The application relates to the technical field of MEMS sensors, in particular to an MEMS sensor and a packaging structure thereof.

Background

Sensors manufactured based on Micro Electro Mechanical Systems (MEMS) are called MEMS sensors, which are valued for their extremely small size and good performance. The MEMS sensor generally includes a MEMS chip and a signal processing chip electrically connected to the MEMS chip, and in order to prevent the chip from being broken and reduce the interference of the environment to the chip, the MEMS chip and the signal processing chip in the MEMS sensor need to be protected by a package structure.

In the packaging process of the MEMS sensor, steps which need to be carried out on a signal processing chip independently are provided, and the micro-electromechanical structure and the signal processing chip are fixed in the same cavity, so that the micro-electromechanical structure is difficult to avoid being influenced. Especially, in the process of spraying the protective adhesive on the surface of the signal processing chip, the protective adhesive is easily splashed onto the sensing film of the micro-electromechanical structure chip, which is not favorable for the stability of the work of the MEMS sensor.

Accordingly, it is desirable to provide a MEMS sensor and a package structure thereof to improve the above-mentioned problems.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides an MEMS sensor and a package structure thereof, in which an opening of an inner casing corresponds to a signal processing chip, and the opening does not expose the MEMS chip, so that the influence and damage to the MEMS chip are reduced when the signal processing chip is processed through the opening.

According to an aspect of an embodiment of the present invention, there is provided a package structure of a MEMS sensor, including: a substrate; the inner shell is fixedly connected with the substrate and forms a cavity with the substrate; and an outer casing surrounding the inner casing, wherein the inner casing has an opening, and the outer casing seals the cavity.

Optionally, the inner casing and the outer casing are fixedly connected by an adhesive layer, wherein the adhesive layer continuously surrounds the inner casing near the base plate.

Optionally, the base plate has a through hole, and the through hole and the opening of the inner casing are staggered.

According to an aspect of an embodiment of the present invention, there is provided a MEMS sensor including: a packaging structure; and the micro electro mechanical structure chip and the signal processing chip are electrically connected, the micro electro mechanical structure chip and the signal processing chip are both positioned in the cavity of the packaging structure, wherein the packaging structure comprises: the inner shell is fixedly connected with the base plate and forms the cavity with the base plate, the outer shell surrounds the inner shell and shields the opening, the signal processing chip is fixed on the base plate, the position of the opening corresponds to the signal processing chip, and the micro-electromechanical structure chip and the opening are staggered mutually.

Optionally, the signal processing device further comprises a protective layer on the surface of the signal processing chip, and the opening serves as a spraying opening for spraying the surface of the signal processing chip to form the protective layer.

Optionally, the size of the opening is not smaller than the size of the signal processing chip.

Optionally, the package structure further includes an adhesive layer fixedly connecting the inner casing and the outer casing, wherein the adhesive layer continuously surrounds the inner casing near the substrate.

Optionally, the substrate has a through hole, and the through hole is staggered with the opening of the inner casing, wherein the micro electromechanical structure chip is fixed on the substrate, and the through hole corresponds to the sensing film of the micro electromechanical structure chip.

Optionally, the mems chip includes at least one of a microphone chip, a pressure sensor chip, and a bone conduction chip.

Optionally, the signal processing chip comprises an audio amplifier chip.

According to the MEMS sensor and the packaging structure thereof provided by the embodiment of the utility model, the packaging structure forms a cavity through the inner shell and the substrate, and the micro-electromechanical structure chip and the signal processing chip of the MEMS sensor are both positioned in the cavity, wherein the inner shell is provided with the opening corresponding to the signal processing chip, and the openings of the micro-electromechanical structure chip and the inner shell are staggered with each other, so that the micro-electromechanical structure chip is not exposed by the opening of the inner shell, and the influence on the micro-electromechanical structure chip is reduced under the condition that the signal processing chip is processed through the opening of the inner shell.

Through the cavity formed by the inner shell and the substrate in the shell body seal, the dirt can be prevented from entering the cavity through the opening of the inner shell in the transportation or practical process of the MEMS sensor, and the cleanliness of the cavity of the MEMS sensor is guaranteed.

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 perspective view of a MEMS sensor structure of an embodiment of the utility model.

Fig. 2-9 show schematic diagrams of some packaging steps of a MEMS sensor of an embodiment of the utility model.

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 MEMS sensor 1000 according to an embodiment of the present invention includes: the chip package comprises a package structure, a micro-electromechanical structure chip 100 and a signal processing chip 200, wherein the micro-electromechanical structure chip 100 is electrically connected with the signal processing chip 200 and is located inside a cavity of the package structure. The packaging structure and packaging steps of the MEMS sensor 1000 will be described in detail with reference to fig. 2 to 9.

In this embodiment, the package structure of the MEMS sensor 1000 includes: base plate 310, inner casing 320, and outer casing 330. During the packaging process, the mems chip 100 and the signal processing chip 200 are required to be fixed on the substrate 310, as shown in fig. 2 and fig. 3, wherein fig. 3 is a cross-sectional view taken along line AA in fig. 2.

In some embodiments, the substrate 310 has a through hole 311, the substrate 310 is implemented by, for example, a Printed Circuit Board (PCB), and the mems chip 100 is a microphone chip, and the back cavity 101 and the sensing film are both connected to the through hole 311. The signal processing chip 200 is an audio amplifier chip, and the signal processing chip 200 is implemented by, for example, an Application Specific Integrated Circuit (ASIC). However, the embodiments of the present invention are not limited thereto, and those skilled in the art may perform other arrangements according to the needs, for example, the mems chip 100 may also be a pressure sensor chip or a bone conduction chip, and the function of the signal processing chip 200 is adjusted accordingly as the kind of the mems chip 100 changes.

In this step, the mems chip 100 and the signal processing chip 200 are fixed on the substrate 310 by an adhesive, wherein the mems chip 100 is bonded to the substrate 310 by a silicone adhesive with stress resistance and buffering function, the signal processing chip 200 is bonded to the substrate 310 by an epoxy adhesive, and the mems chip 100, the signal processing chip 200 and the substrate 310 are electrically connected by a bonding wire.

Further, an inner housing 320 is fastened on the substrate 310, and the inner housing 320 is fixedly connected to the substrate 310 and forms a cavity 301 with the substrate 310 for accommodating the mems chip 100 and the signal processing chip 200, as shown in fig. 4 and 5, where fig. 5 is a cross-sectional view taken along line AA in fig. 4. In this step, the inner case 320 is attached to the solder ring of the substrate 310 by SMT technique using solder paste.

In this embodiment, the inner casing 320 has an opening 321, the position of the opening 321 corresponds to the signal processing chip 200, the through hole 311 and the mems chip 100 are staggered from the opening 321, and the top of the mems chip 100 is covered by the inner casing 320.

In some specific embodiments, the material of the inner casing 320 is a metal or an insulating material, and the size of the opening 321 of the inner casing 320 is not smaller than the size of the signal processing chip 200. However, the embodiments of the present invention are not limited thereto, and those skilled in the art may make other arrangements for the material of the inner casing 320 and the size of the opening 321 as needed.

Further, the protective layer 10 is formed on the surface of the signal processing chip 200, and the opening 321 of the inner casing 320 serves as a spraying opening for spraying the surface of the signal processing chip 200 to form the protective layer 10, as shown in fig. 6 and 7, where fig. 7 is a cross-sectional view taken along line AA in fig. 6.

In this step, the protective layer 10 is a colloid, and in the process of spraying the colloid on the surface of the signal processing chip 200 through the opening 321, since the top of the micro electromechanical structure chip 100 is shielded by the inner casing 320, the colloid cannot easily splash onto the micro electromechanical structure chip 100 and into the cavity 301 shielded by the inner casing 320, so that not only is the micro electromechanical structure chip 100 protected, but also the cleanliness inside the cavity 301 is ensured to a certain extent.

However, the present invention is not limited thereto, and the opening 321 of the inner casing 320 may also play a role in other packaging steps only for the signal processing chip 200, thereby protecting the electrical structure chip 100.

Further, an adhesive layer 20 is formed on the surface of the inner casing 320, as shown in fig. 6 and 7, wherein the adhesive layer 20 continuously surrounds the inner casing 320 near the substrate 100, and the material of the adhesive layer 20 includes, but is not limited to, solder paste.

Further, the inner casing 320 is enclosed by an outer casing 330 and fastened to the base plate 310 to cover the opening 321 of the inner casing 320 and close the cavity 301, as shown in fig. 8 and 9, wherein fig. 9 is a cross-sectional view taken along line AA in fig. 8.

In this step, for example, the outer shell 330 is attached to the inner shell 320 by using an SMT technique, and the outer shell 330 is fixedly connected to the inner shell 320 by the adhesive layer 20, and since the adhesive layer 20 continuously surrounds the inner shell 320, the outer shell 330 can better close the cavity 301, thereby improving the tightness of the cavity 301. In some other embodiments, the outer housing 330 is also fixedly connected to the base plate 310. In some specific embodiments, the material of the outer housing 330 is a metal or an insulating material.

Compared with the packaging process of the MEMS sensor, the surface mounting process can enable the MEMS sensor to bear high reflow soldering temperature, is easy to integrate with CMOS process and other audio circuits, and has improved noise elimination performance and good RF and EMI inhibition performance.

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 package structure of a MEMS sensor, comprising:

a substrate;

the inner shell is fixedly connected with the substrate and forms a cavity with the substrate; and

an outer casing surrounding the inner casing,

wherein the inner casing has an opening and the outer casing seals the cavity.

2. The packaging structure of claim 1, further comprising an adhesive layer fixedly connecting the inner casing and the outer casing,

wherein the adhesive layer continuously surrounds the inner case near the substrate.

3. The package structure of claim 1, wherein the substrate has a through hole that is offset from the opening of the inner housing.

4. A MEMS sensor, comprising:

a packaging structure; and

the micro electro mechanical structure chip and the signal processing chip are electrically connected and are both positioned in the cavity of the packaging structure,

wherein, the packaging structure includes: the inner shell is fixedly connected with the base plate and forms the cavity with the base plate, the outer shell surrounds the inner shell and shields the opening,

the signal processing chip is fixed on the substrate, the position of the opening corresponds to the signal processing chip, and the micro-electromechanical structure chip and the opening are staggered.

5. The MEMS sensor according to claim 4, further comprising a protective layer on the surface of the signal processing chip, wherein the opening is used as a spraying port for spraying the surface of the signal processing chip to form the protective layer.

6. The MEMS sensor according to claim 4, wherein the opening has a size not smaller than a size of the signal processing chip.

7. The MEMS sensor of claim 4, wherein the package structure further comprises an adhesive layer fixedly connecting the inner casing and the outer casing,

8. The MEMS sensor of claim 4, wherein the substrate has a through hole that is offset from the inner housing opening,

the micro-electromechanical structure chip is fixed on the substrate, and the through hole corresponds to the induction film of the micro-electromechanical structure chip.

9. The MEMS sensor according to any of claims 4 to 7, wherein the micro-electromechanical structure chip comprises at least one of a microphone chip, a pressure sensor chip, a bone conduction chip.

10. The MEMS sensor according to any of claims 4 to 7, wherein the signal processing chip comprises an audio amplifier chip.