CN215420756U

CN215420756U - Vibration sensor packaging structure

Info

Publication number: CN215420756U
Application number: CN202120600995.0U
Authority: CN
Inventors: 唐行明; 梅嘉欣
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2021-03-24
Filing date: 2021-03-24
Publication date: 2022-01-04
Anticipated expiration: 2031-03-24

Abstract

Disclosed is a vibration sensor package structure, including: a substrate; the packaging shell is fixed on the first surface of the substrate, and a first cavity is formed between the packaging shell and the substrate; the MEMS chip is fixed on the first surface of the substrate and is positioned in the first cavity, and a second cavity is formed between the MEMS chip and the substrate; the substrate is provided with a first air hole and a second air hole which penetrate through the substrate; the first cavity is communicated with the outside through a second air hole, and the second cavity is communicated with the outside through the first air hole. The utility model provides a vibration sensor packaging structure is through forming the first gas pocket and the second gas pocket that run through the base plate in the base plate for the sound signal in the air can all be accepted to the upper and lower both sides of the vibrating diaphragm of MEMS chip, thereby has reduced the noise interference that the sound signal in the air brought for vibration sensor, has improved the yield and the reliability of device.

Description

Vibration sensor packaging structure

Technical Field

The utility model relates to the technical field of MEMS devices, in particular to a vibration sensor packaging structure.

Background

Vibrations are widely present in nature, industry and human life, and various vibrations transmit various signals. The information carried in the vibration is acquired by means of various vibration sensors, and the vibration sensors are widely applied to various fields such as energy, chemical industry, medicine, automobiles, metallurgy, machine manufacturing, military industry, scientific research and teaching and the like. Reading the sound signal transmitted by the air vibration through a microphone; the accelerometer is used for measuring the acceleration of the vibrating object; the ultrasonic detector detects and analyzes a vibration signal of mechanical equipment, and is used for judging the self degradation degree of the machine and predicting the service life of the machine; the geological disaster early warning device detects geological vibration caused by seismic waves to early warn disasters such as earthquakes and the like.

Common sensors in the market at present include a microphone sensor, a pressure sensor and an acceleration sensor, and a bone conduction microphone for converting a sound signal by vibration is extended from the microphone sensor, and the traditional bone conduction microphone is used for transmitting compressed air to an MEMS diaphragm by vibration of a mass block. However, the vibration microphone in the prior art is easily affected by the sound signal transmitted in the air, which causes high noise in the received signal, thereby reducing the yield and reliability of the vibration sensor.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, an object of the present invention is to provide a vibration sensor package structure, which reduces the influence of an acoustic signal in a signal received by a sensor on a vibration signal by changing the path of air flowing in the vibration sensor, thereby improving the yield and reliability of the vibration sensor.

According to an aspect of the present invention, there is provided a vibration sensor package structure, comprising: a substrate; the packaging shell is fixed on the first surface of the substrate, and a first cavity is formed between the packaging shell and the substrate; the MEMS chip is fixed on the first surface of the substrate and is positioned in the first cavity, and the MEMS chip is provided with a second cavity; the substrate is provided with a first air hole and a second air hole which penetrate through the substrate; one side of the MEMS chip is communicated with the outside through the first cavity and the second air hole, and the other side of the MEMS chip is communicated with the outside through the second cavity and the first air hole.

Optionally, a cross-sectional shape of the second air hole along the first surface of the substrate is any one of a square, a circle, and a polygon.

Optionally, the cross-sectional shape of the second air hole along a direction perpendicular to the first surface of the substrate is any one of a trapezoid, a rectangle, an arc and a polygon.

Optionally, the second air hole comprises one or more air holes, and the one or more air holes are positioned in the substrate on one side or more sides of the MEMS chip.

Optionally, the MEMS chip includes a support structure, and a bottom of the support structure is fixed on the substrate surface through a glue.

Optionally, the MEMS chip further includes a diaphragm and a back plate, and positions of the diaphragm and the back plate may be interchanged.

Optionally, the method further comprises: an ASIC chip, the MEMS chip electrically connected with the ASIC chip.

Optionally, the method further comprises: and the sealing ring is positioned on the first surface of the substrate, and the packaging shell is fixed with the substrate through the sealing ring.

Optionally, the second surface of the substrate includes a first pad and a second pad.

Optionally, the first pad surrounds the first air hole and the second air hole.

According to the packaging structure of the vibration sensor, the first air hole is formed in the substrate below the second cavity of the MEMS chip, the second air hole is formed in the substrate below the first cavity, so that the time difference between the sound signal reaching the surface of the vibrating diaphragm of the MEMS chip along the second air hole and the sound signal reaching the surface of the vibrating diaphragm of the MEMS chip along the first air hole can be basically ignored, the sound on the upper surface and the sound on the lower surface of the vibrating diaphragm of the MEMS chip are offset, and the MEMS chip only receives the vibration signal, so that the noise interference of the sound signal on the vibration sensor can be reduced to the greatest extent. Thereby improving the yield and reliability of the vibration sensor.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

FIG. 1 shows a block diagram of a vibration sensor package structure of an embodiment of the utility model;

FIGS. 2a and 2b illustrate a first surface schematic of a substrate in a vibration sensor package structure according to an embodiment of the utility model;

fig. 3 is a schematic diagram of a second surface of a substrate in a vibration sensor package structure according to an 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 above another layer, another area, the expression "directly above … …" or "above and adjacent to … …" will be used herein.

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples.

FIG. 1 shows a block diagram of a vibration sensor package structure of an embodiment of the utility model; FIGS. 2a and 2b illustrate a first surface schematic of a substrate in a vibration sensor package structure according to an embodiment of the utility model; fig. 3 is a schematic diagram of a second surface of a substrate in a vibration sensor package structure according to an embodiment of the present invention.

Referring to fig. 1, a vibration sensor package structure 100 of an embodiment of the present invention includes: a substrate 3, wherein a first air hole 5 penetrating through the substrate 3 and a second air hole 4 penetrating through the substrate 3 are formed in the substrate 3; the packaging structure comprises a packaging shell 1, a first cavity 2 is formed between the packaging shell 1 and a substrate 3, and a first air hole 5 and a second air hole 4 are both positioned in the first cavity 2; MEMS chip 10, set up in first cavity 2, MEMS chip 10 includes vibrating diaphragm 11, back plate 12 and bearing structure, bearing structure top support vibrating diaphragm 11 and back plate 12, the bottom is fixed in the first surface of base plate 3, between vibrating diaphragm 11 and back plate 12 at bearing structure top and the base plate 3 of bottom, form second cavity 6, second cavity 6 is located the top of first gas pocket 5, make second cavity 6 communicate with the outside via first gas pocket 5, first cavity 2 also communicates with the outside via second gas pocket 4 simultaneously.

The vibration sensor package structure 100 further includes an ASIC chip 13 disposed on the first surface of the substrate 3 in the first cavity 2, wherein the ASIC chip 13 is an ASIC chip and is connected to the MEMS chip 10 through a wire 14. In this embodiment, the asic chip 13 is fixed to the first surface of the substrate 3. In other embodiments, the asic chip 13 may also be embedded or integrated inside the substrate 3. The asic chip 13 is used for acquiring and processing the sensing signal output by the MEMS chip 10.

The substrate 3 may be made of a conventional substrate material such as RF-4, BT or ceramic substrate. On the first surface of the substrate 3, a sealing ring 15 is further formed around the edge of the first surface of the substrate 3, and referring to fig. 2a and 2b, the package housing 1 is fixedly connected to the first surface of the substrate 3 through the sealing ring 15 to form the first cavity 2. The second surface of the substrate 3 is formed with first pads 7 and/or second pads 9 for providing electrical connection points, as shown in fig. 3. The substrate 3 may be a single-layer or multi-layer circuit board, and the first surface of the substrate 3 may also be formed with circuit structures, or electrical contacts, such as pads, etc. The substrate 3 may also be formed with an electrical connection structure inside for connecting electrical contacts of the first surface and the second surface of the substrate 3.

The package body 1 serves as a package shell of the vibration sensor package structure, and is used for protecting internal electronic components, and a first cavity 2 is formed between the package body and the substrate 3. The packaging shell 1 can be made of metal, is high-temperature resistant and simple in production process, can be produced in large scale, has the characteristics of corrosion resistance, electromagnetic shielding effect, high mechanical property and the like, and has a high protection effect on products. In other embodiments, the package housing 1 may also be made of other hard materials such as plastic, which is not limited herein. The edge of the package housing 1 is fixed to the sealing ring 15 on the first surface of the substrate 3 by welding or gluing, so that the first cavity 2 is formed between the package housing 1 and the substrate 3.

The MEMS chip 10 acts as an inductive element for the sound signal, and the positions of the diaphragm 11 and the back plate 12 can be interchanged. The bottom of the MEMS chip 10 is fixedly connected to the first surface of the substrate 3 through the glue 8.

Referring to fig. 1, the first surface of the substrate 3 has a first air hole 5 and a second air hole 4, wherein the first air hole 5 and the second air hole 4 both penetrate through the substrate 3, and the second air hole 4 is located near the first air hole 5, specifically, the first air hole 5 is located in the substrate 3 in the second cavity 6 of the MEMS chip 10, and the second air hole 4 is located in the substrate 3 outside the MEMS chip 10, so that the second cavity 6 communicates with the outside through the first air hole 5, and the first cavity 2 communicates with the outside through the second air hole 4, referring to the schematic top view of the first surface of the substrate 3 shown in fig. 2a and 2b, wherein fig. 2a further includes the MEMS chip 10 and the asic chip 13. In some embodiments, the cross-section of the second air hole 4 in a direction parallel to the first surface of the substrate 100 may be square, circular, polygonal, or the like. In some embodiments, the cross-sectional shape of the second air hole 4 along the direction perpendicular to the first surface of the substrate 3 is trapezoidal, rectangular, circular, or polygonal. The second air hole 4 only needs to penetrate through the substrate 3 and can communicate the first cavity 2 with the external environment, preferably, the second air hole 4 is located near the MEMS chip, and a person skilled in the art can reasonably set the shape of the second air hole 4. The size of the second air hole 4 is adjusted according to the size of the second cavity 6 and/or the first air hole 5 of the MEMS chip 10.

In other embodiments, the second air holes 4 comprise one or more air holes distributed in the substrate 3 around the MEMS chip 10 at one or more sides outside the MEMS chip 10. The first air hole 5 and the second air hole 4 are communicated with the same external environment, so that the air pressure reaching the upper side and the lower side of the vibrating diaphragm 11 of the MEMS chip 10 is the same, and the interference can be reduced to the greatest extent.

The MEMS chip 10 comprises a second cavity 6 as a back cavity. The pressure sensing layer of the MEMS chip 10 includes a back plate 12 and a vibrating membrane layer 11, and the back plate 12 and the vibrating membrane layer 11 are disposed opposite to each other to form an inductive capacitor. When the pressure in the second cavity 6 changes, the pressure sensing layer deforms, so that the capacitance value changes, and a sensing signal is output.

The support structure of the MEMS chip 10 is fixed to the first surface of the substrate 3 by the glue 8. When the MEMS chip 10 is fixed, a certain acting force is applied to the MEMS chip 10 through equipment, so that the bottom of the supporting structure and the colloid 8 have a larger contact area, and the fixing effect is improved. The colloid receives the extrusion, can spill over to the both sides of bearing structure bottom, spills over to bearing structure's both sides to upwards climb the take the altitude along the outer wall of MEMS chip 10, follow-up colloid solidifies under certain temperature and certain time, realizes microphone chip 10 and base plate 3's zonulae occludens.

When the vibration sensor is applied, a caller makes a sound, and the sound reaches the vibration sensor through two channels of air and vibration. Wherein, the sound signal in the air reaches the second cavity 6 of the MEMS chip 10 through the first air hole 5, so that the capacitance between the diaphragm 11 and the back plate 12 changes, thereby obtaining the sound signal. The sound signal transmitted by the vibration reaches the diaphragm 11 and the back plate 12 of the MEMS chip 10 along the structure of the vibration sensor, so that the capacitance between the diaphragm 11 and the back plate 12 changes, thereby obtaining a signal. However, in the vibration sensor, the capacitance change between the diaphragm 11 and the back plate 12 caused by the sound signal in the air causes noise interference in the sound signal obtained by the vibration. In this embodiment, a part of the sound signal in the air reaches the second cavity 6 of the MEMS chip 10 along the first air hole 5, and the pressing diaphragm 11 vibrates, and a part of the sound signal reaches the MEMS chip 10 along the second air hole 4 and the first cavity 2, and the pressing diaphragm 11 vibrates in the opposite direction, so that the sound signal in the air is cancelled due to the same diaphragm 11 acted by the same air pressure in the two opposite directions. When the voice sent by the caller is transmitted to the earphone through the oral cavity bone and is close to the vibration sensor of the bone direction, the vibration is transmitted to the substrate 3 of the vibration sensor through the earphone shell and then transmitted to the MEMS chip 10, so that the vibrating diaphragm 11 on the surface of the MEMS chip 10 is driven to vibrate to form a parallel plate capacitor with the back plate 12 of the MEMS chip 10, and the integrated circuit chip 13 receives the signal of the capacitance change for processing.

When talking in noisy environment, the vibration sensor of the application can automatically shield sound signals, and only transmits the sound signals transmitted by bone vibration when the talker speaks, so that the highest quality noise reduction is achieved.

In addition, the vibration sensor is not only used for a conversation earphone, but also can be applied to other electronic products working on the same principle.

According to the packaging structure of the vibration sensor, the first air hole and the second air hole penetrating through the substrate are formed in the substrate, wherein the first air hole is communicated with the second cavity of the MEMS chip, and the second air hole is communicated with the first cavity, so that the surface, facing the first cavity, of the MEMS chip can also receive air and pressure, noise interference brought to the vibration sensor by sound signals when the air and the pressure are received by the second cavity of the MEMS chip is reduced, and the yield and the reliability of the vibration sensor are improved.

According to the vibration sensor packaging structure provided by the utility model, the first air hole is formed in the substrate below the second cavity of the MEMS chip, and the second air hole is formed in the area, close to the MEMS chip, in the substrate, so that when the sound signal reaches the surface, facing the first cavity, of the MEMS chip along the second air hole, the time difference between the sound signal and the surface, reaching the second cavity of the MEMS chip along the first air hole, of the sound signal is smaller, and the sound signal is the same, so that the noise interference of the sound signal on the vibration sensor can be reduced to the greatest extent.

In accordance with the embodiments of the present invention as set forth above, these embodiments are not exhaustive and do not limit the utility model to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the utility model and the practical application, to thereby enable others skilled in the art to best utilize the utility model and various embodiments with various modifications as are suited to the particular use contemplated. The utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A vibration sensor package structure, comprising:

a substrate;

the packaging shell is fixed on the first surface of the substrate, and a first cavity is formed between the packaging shell and the substrate;

the MEMS chip is fixed on the first surface of the substrate and is positioned in the first cavity, and a second cavity is formed between the MEMS chip and the substrate;

the substrate is provided with a first air hole and a second air hole which penetrate through the substrate;

the first cavity is communicated with the outside through a second air hole, and the second cavity is communicated with the outside through the first air hole.

2. The vibration sensor package structure according to claim 1, wherein a cross-sectional shape of the first air hole or the second air hole along the first surface of the substrate is any one of a square shape, a circular shape, and a polygonal shape.

3. The vibration sensor package structure according to claim 1, wherein a cross-sectional shape of the first air hole or the second air hole along a direction perpendicular to the first surface of the substrate is any one of a trapezoid, a rectangle, an arc, and a polygon.

4. The vibration sensor package structure of claim 1, wherein the second air holes comprise one or more air holes in the substrate on one or more sides of the MEMS chip.

5. The vibration sensor package structure of claim 1, wherein the MEMS chip comprises a support structure, and a bottom of the support structure is fixed on the substrate surface by an adhesive.

6. The vibrating sensor package of claim 5, wherein the MEMS chip further comprises a diaphragm and a backplate, and the positions of the diaphragm and the backplate are interchangeable.

7. The vibration sensor package structure of claim 1, further comprising: an ASIC chip, the MEMS chip electrically connected with the ASIC chip.

8. The vibration sensor package structure of claim 1, further comprising: and the sealing ring is positioned on the first surface of the substrate, and the packaging shell is fixed with the substrate through the sealing ring.

9. The vibration sensor package structure of claim 1, wherein the second surface of the substrate includes first and second pads.

10. The vibration sensor package structure of claim 9, wherein the first pad surrounds the first air hole and the second air hole.