WO2022007045A1

WO2022007045A1 - Mems sensor

Info

Publication number: WO2022007045A1
Application number: PCT/CN2020/105092
Authority: WO
Inventors: 洪亭亭; 柏杨; 饶成辉
Original assignee: 瑞声声学科技(深圳)有限公司; 瑞声科技（南京）有限公司
Priority date: 2020-07-08
Filing date: 2020-07-28
Publication date: 2022-01-13
Also published as: CN215924387U

Abstract

An MEMS sensor, comprising a substrate (100), a housing (200) and an insulating thermal insulation layer (300); the substrate (100) is used for mounting an MEMS chip (1000) and an ASIC chip (2000), the housing (200) covers the substrate (100) and forms an encapsulation chamber (101) by enclosing together with the substrate (100); the MEMS chip (1000) and the ASIC chip (2000) are located in the encapsulation chamber (101), a sensing channel (102) in communication with the encapsulation chamber is provided on the housing (200) and/or the substrate (100), so as to facilitate the MEMS chip (1000) to sense a measured physical quantity, and the insulating thermal insulation layer (300) is provided in the sensing channel (102) and/or covers the ASIC chip (2000). By means of the arrangement of the insulating thermal insulation layer (300), even if temperature changes occur outside the encapsulation chamber (101), the measurement accuracy of the EMES sensor will not be greatly affected, and the use stability and the measurement accuracy of the MEMS sensor can be improved.

Description

A MEMS sensor

technical field

The present application relates to the technical field of MEMS sensors, and in particular, to a MEMS sensor.

Background technique

With the continuous development of technology, the functions of electronic devices are becoming more and more powerful, and the detection accuracy requirements of MEMS sensors (MEMS microphones, MEMS ultrasonic transducers, pressure sensors, etc.) are also getting higher and higher, but the output signals of MEMS sensors are extremely It is easily affected by temperature changes in its working environment, which will affect the detection accuracy of MEMS. For example, taking mobile devices such as mobile phones and tablets as an example, MEMS sensors are usually arranged in the casing of the mobile device and may be close to the power device of the mobile device. The power device will generate heat during its operation and transfer it to the MEMS sensor. This affects the detection accuracy of the MEMS sensor.

technical problem

Based on this, in order to weaken the influence of temperature changes on the MEMS sensor, the MEMS sensor usually needs to be packaged in the prior art, which is usually surrounded by a shell and a substrate to form a package cavity, and then the corresponding components, such as MEMS chips and ASIC chips, are packaged. It is packaged into the package cavity, but this form of package structure needs to leave a channel for the MEMS chip to sense the measured physical quantity (sound signal or pressure signal), which will cause heat to be easily transferred to the MEMS chip. The improvement in resistance to temperature changes is not significant.

Therefore, it is necessary to provide a MEMS sensor that can resist temperature changes.

technical solutions

The purpose of the present application is to provide a MEMS sensor, so that the MEMS sensor can resist temperature changes and improve the detection accuracy of the MEMS sensor.

The embodiment of the present application provides a MEMS sensor, including:

Substrate for mounting MEMS chips and ASIC chips;

a casing, the casing is covered on the substrate, and is enclosed with the substrate to form a packaging cavity, the MEMS chip and the ASIC chip are located in the packaging cavity, and the casing and/or the substrate are A sensing channel connected to the packaging cavity is opened, so that the MEMS chip can sense the measured physical quantity;

and an insulating and insulating layer, the insulating and insulating layer is arranged in the sensing channel and/or covers the ASIC chip.

In some embodiments of the MEMS sensor, the sensing channel is opened on the substrate, and the insulating layer covers the sensing channel.

In some embodiments of the MEMS sensor, the substrate includes an upper surface close to the package cavity and a lower surface opposite to the upper surface, the substrate is recessed from the upper surface to the lower surface to form the insulating spacer Grooves for the thermal layer.

In some embodiments of the MEMS sensor, the substrate includes an upper surface adjacent to the package cavity and a lower surface opposite to the upper surface, the substrate is recessed from the lower surface to the upper surface to accommodate the insulating heat shield layer grooves.

In some embodiments of the MEMS sensor, a groove for accommodating the insulating and heat insulating layer is provided between the upper surface and the lower surface of the substrate.

In some embodiments of the MEMS sensor, the MEMS sensor is further provided with a ring-shaped and hollow dust-proof net, and the dust-proof net is stacked on the insulating and heat-insulating layer.

In some embodiments of the MEMS sensor, a wire sealing glue is provided between the insulating and heat insulating layer and the ASIC chip.

In some embodiments of the MEMS sensor, the ASIC chip is fixed on the substrate by the wire-sealing glue, and at least one layer of the insulating and heat-insulating layer is covered on the wire-sealing glue.

In some embodiments of the MEMS sensor, wires are connected between the substrate and the ASIC chip, and between the ASIC chip and the MEMS chip.

In some embodiments of the MEMS sensor, the thermal conductivity of the material used for the insulation and heat insulation layer is lower than the thermal conductivity of the material used for the housing, or the specific heat capacity of the material used for the insulation and heat insulation layer is higher than the The specific heat capacity of the material used for the housing.

In some embodiments of the MEMS sensor, the insulating layer is made of polyimide, epoxy or glass material.

beneficial effect

The beneficial effect of the present application is that: since the insulating and heat-insulating layer is provided in the sensing channel and/or on the ASIC chip, heat exchange between the package cavity and the outside through the sensing channel, the substrate or the casing can be prevented. The temperature change outside the package cavity will not have a great impact on the detection accuracy of the EMES sensor, which can improve the stability and detection accuracy of the MEMS sensor.

Description of drawings

1 is a schematic structural diagram of a MEMS sensor in an embodiment of the application;

2 is a schematic structural diagram of a MEMS sensor in another embodiment of the present application;

FIG. 3 is a schematic structural diagram of a MEMS sensor in still another embodiment of the present application.

Description of main component symbols:

100-substrate; 200-shell; 300-insulation layer; 400-dust net; 101-package cavity; 102-sensing channel; 103-groove; 210-top wall; 220-side wall; 1000-MEMS Chip; 2000-ASIC chip; 3000-wire; 4000-sealing glue.

Embodiments of the present invention

The present application will be further described below with reference to the accompanying drawings and embodiments.

The embodiments of the present application provide a MEMS sensor (hereinafter referred to as "sensor"), which is more reasonable in structure than the traditional design method, which can not only sensitively sense the measured physical quantity from the outside world, but also can Preventing heat exchange between the inner space of the sensor and the outside world can improve the detection accuracy of the MEMS sensor.

In this embodiment of the present application, the sensor includes a substrate 100 , a housing 200 and an insulating layer 300 .

The substrate 100 is used for supporting, and the MEMS chip 1000 and the ASIC chip 2000 are mounted on the substrate 100 .

Specifically, the substrate 100 may be made of materials such as silicon nitride ceramics. The ASIC chip 2000 is an integrated circuit, which plays the role of data processing and control. The MEMS chip 1000 and the ASIC chip 2000 need to be fixed on the substrate 100, and can be fixed by means of wire sealing glue.

The casing 200 is covered on the substrate 100, and is enclosed with the substrate 100 to form a packaging cavity 101. The MEMS chip 1000 and the ASIC chip 2000 are located in the packaging cavity 101, between the substrate 100 and the ASIC chip 2000, and the ASIC chip 2000 and the MEMS chip Wires 3000 are connected between the chips 1000 to establish an electrical connection between the two, and pads can also be arranged on the inside and outside of the substrate 100 so that the MEMS sensor can be integrated with other components in the application equipment such as electronic equipment as a whole. The connection is formed so that the MEMS sensor can be applied to various application devices. The housing 200 and/or the substrate 100 are provided with a sensing channel 102 connected to the package cavity 101 , so that the MEMS chip 1000 can sense the measured physical quantity.

Specifically, the shell 200 can be made of metal material, which is generally designed to be a wrapping structure that can surround a certain space area, so that after being disposed on the substrate 100 , an encapsulation cavity 101 can be formed with the substrate 100 .

It should be noted that the measured physical quantity described here refers to the physical quantity that can be detected by the MEMS chip 1000 , which is generally a pressure signal or a sound signal. When it is a sound signal, the corresponding MEMS sensor may be a MEMS microphone, a MEMS ultrasonic Transducers, etc., when it is a pressure signal, the corresponding MEMS sensor can be a pressure sensor.

The insulating and heat insulating layer 300 is disposed in the sensing channel 101 and/or covers the ASIC chip, and can at least play the role of insulation and heat insulation. The insulation can prevent signal interference from occurring, and the heat insulation can prevent heat from passing through the sensing channel 102 into the packaging cavity 101 .

In the embodiment of the present application, since the insulating layer 300 is provided in the sensing channel 102 and/or on the ASIC chip 2000 , heat exchange between the package cavity 101 and the outside through the sensing channel 102 , the housing 200 or the substrate 100 can be prevented , under this condition, even if there is a temperature change outside the package cavity 101 , it will not greatly affect the detection accuracy of the EMES sensor, which can improve the use stability and detection accuracy of the MEMS sensor.

In one embodiment, please refer to FIGS. 1-3 , the substrate 100 has a rectangular parallelepiped structure, and the housing 200 is designed as a wrapping structure, and the wrapping structure includes a top wall 210 and a side extending from the edge of the top wall 210 The space enclosed by the wall 220, the top wall 210 and the side wall 220 can surround a certain space area. After the casing 200 is covered on the substrate 100 , the side wall 220 is attached to the surface of the casing 200 , thereby forming the packaging cavity 101 .

It should be noted that, in other embodiments, the substrate 100 and the housing 200 may also have various other structures. For example, the substrate 100 does not have to be a rectangular parallelepiped structure, it can also be a circular structure, etc., and the housing 200 does not have to be made of The top wall 210 and the side wall 220 are formed, which can also be integrally bent from a metal sheet.

In one embodiment, the sensing channel 102 is disposed on the substrate 100, and the MEMS chip is disposed at one end of the sensing channel 102 located in the packaging cavity 101, thereby increasing the sensitivity of the MEMS chip 1000 to the measured physical quantity, thereby improving detection precision.

On the other hand, in the specific design, the structure of the substrate 100 is generally designed to be more regular, and the thickness of the substrate 100 is generally thicker than that of the housing 200, which simplifies the design of the sensing channel 102, is easy to implement, and can be The arrangement of the insulating and insulating layers 300 provides various options, which are not only reflected in that the insulating and insulating layers 300 can be arranged at different positions, but also more flexible in the choice of the number of layers of the insulating and insulating layers 300 . In addition, it should be noted that when disposing the insulating and heat-insulating layer 300, a better way is to enable the insulating and heat-insulating layer 300 to cover the sensing channel, so as to improve the insulating and heat-insulating effect.

For example, in a specific embodiment, please refer to FIG. 1 , the insulating and heat-insulating layer 300 is disposed at one end of the sensing channel 102 located in the package cavity 101 . At this time, the insulating and heat-insulating layer 300 is relatively close to the MEMS chip 1000 , and A sufficient space is left between the insulating and insulating layer 300 and the other end of the sensing channel 102 , and more layers of insulating and insulating layers 300 can be arranged in the space.

Specifically, the substrate 100 includes an upper surface 110 close to the packaging cavity 101 and a lower surface 120 opposite to the upper surface 110 .

For another example, in another specific embodiment, please refer to FIG. 2 , the insulating and heat-insulating layer 300 is disposed at one end of the sensing channel 102 away from the package cavity 101 . At this time, the insulating and heat-insulating layer 300 is relatively far away from the MEMS chip 1000 . However, a sufficient space is left between the insulating and insulating layer 300 and the other end of the sensing channel 102 , and more layers of insulating and insulating layers 300 can be arranged in the space.

For another example, in another specific embodiment, please refer to FIG. 3 , the insulating and insulating layer 300 is arranged in the middle position of the sensing channel 102 , and at this time, more layers of insulating layers can be arranged on both sides of the insulating insulating layer 300 isolation layer 300 .

Specifically, the substrate 100 includes an upper surface 110 close to the package cavity 101 and a lower surface 120 opposite to the upper surface 110 , and a groove 103 for accommodating the insulating and heat insulating layer 300 is provided between the upper surface 110 and the lower surface 120 .

In one embodiment, the sensor may further include a ring-shaped and hollow dust-proof mesh 400, which is disposed in the sensing channel 101, and the dust-proof mesh 400 can improve the dust-proof capability of the MEMS sensor.

In a specific embodiment, the dustproof net 400 is disposed separately from the aforementioned insulating layer 300, and there is a certain distance between the two. In another specific embodiment, the dustproof net 400 can also be stacked with the insulating and heat-insulating layer 300. In this case, it should be noted that the dustproof net 400 is preferably made of heat-insulating material. In addition to the dust function, it can also play a role in further heat insulation, so as to further improve the detection accuracy of the MEMS sensor.

The above embodiments describe the arrangement and function of the insulating and heat insulating layer 300 from the perspective of the sensing channel 101 . In more cases, the ASIC chip 2000 can also be insulated.

For example, in the example shown in FIGS. 1-3 , the ASIC chip 2000 is fixed on the substrate 100 by the wire sealing glue 4000 , and the wire sealing glue 4000 is covered with at least one insulating layer 300 , so that the MEMS can be further improved. The detection accuracy of the sensor.

It should be noted that, in the above-listed embodiments of the present application, in order to achieve the effect of the insulating and insulating layer 300, when the insulating and insulating layer 300 is arranged in the sensing channel 101, the heat of the material used for the insulating and insulating layer 300 The conductivity is lower than the thermal conductivity of the material used for the substrate 100 , or the specific heat capacity of the material used for the insulating and heat-insulating layer is higher than the specific heat capacity of the material used for the substrate 100 . When the insulation layer 300 is disposed on the wire sealing glue 4000, the thermal conductivity of the material used for the insulation layer 300 is lower than the thermal conductivity of the material used for the casing 200, or the specific heat capacity of the material used for the insulation layer 300 is higher than that of the casing 200 Specific heat capacity of the material used.

In some specific embodiments, the insulating and heat insulating layer 300 is made of materials such as polyimide, epoxy resin or glass.

The above are only the embodiments of the present application. It should be pointed out that for those of ordinary skill in the art, improvements can be made without departing from the creative concept of the present application, but these belong to the present application. scope of protection.

Claims

A MEMS sensor, comprising:

Substrate for mounting MEMS chips and ASIC chips;

a casing, the casing is covered on the substrate, and is enclosed with the substrate to form a packaging cavity, the MEMS chip and the ASIC chip are located in the packaging cavity, and the casing and/or the substrate are A sensing channel connected to the packaging cavity is opened, so that the MEMS chip can sense the measured physical quantity;

and an insulating and insulating layer, the insulating and insulating layer is arranged in the sensing channel and/or covers the ASIC chip.
The MEMS sensor according to claim 1, wherein the sensing channel is opened on the substrate, and the insulating layer covers the sensing channel.
The MEMS sensor according to claim 2, wherein the substrate comprises an upper surface close to the packaging cavity and a lower surface opposite to the upper surface, the substrate is recessed from the upper surface to the lower surface to form a receiving space The groove of the insulating and heat insulating layer.
The MEMS sensor according to claim 2, wherein the substrate comprises an upper surface close to the packaging cavity and a lower surface opposite to the upper surface, the substrate is recessed from the lower surface to the upper surface to accommodate the Grooves for insulating insulation.
The MEMS sensor according to claim 2, wherein a groove for accommodating the insulating and heat insulating layer is provided between the upper surface and the lower surface of the substrate.
The MEMS sensor according to claim 2, characterized in that, the MEMS sensor is further provided with a ring-shaped and hollow dustproof net, and the dustproof net and the insulating layer are stacked.
The MEMS sensor according to claim 1, wherein a wire sealing glue is provided between the insulating and heat insulating layer and the ASIC chip.
The MEMS sensor according to claim 7, wherein the ASIC chip is fixed on the substrate by the wire sealing glue, and at least one layer of the insulating and heat insulation layer is covered on the wire sealing glue.
The MEMS sensor according to claim 1, wherein wires are connected between the substrate and the ASIC chip and between the ASIC chip and the MEMS chip.
The MEMS sensor according to any one of claims 1 to 9, wherein the thermal conductivity of the material used for the insulating and heat insulating layer is lower than the thermal conductivity of the material used for the housing, or the insulating heat insulating layer is used for thermal conductivity. The specific heat capacity of the material used for the layer is higher than the specific heat capacity of the material used for the casing.
The MEMS sensor according to claim 10, wherein the insulating and heat insulating layer is made of polyimide, epoxy resin or glass material.