CN211504505U - Sensor packaging structure - Google Patents

Abstract

A sensor package structure, the sensor package structure comprising: the substrate is provided with a first surface and a second surface which are opposite, the edge of the shell is fixed on the first surface of the substrate, and a first cavity is formed between the shell and the substrate; the pressure sensing element is fixed on the first surface of the substrate and is positioned in the first cavity, the pressure sensing element is provided with a second cavity and a pressure sensing layer, and the pressure sensing layer is positioned between the first cavity and the second cavity; the first cavity is communicated with the outside through a first through hole, and the second cavity is communicated with the outside through a second through hole. The sensor has small size, low power consumption and high reliability.

Description

Sensor packaging structure

The present application claims priority from chinese application No. 2019204697499 filed on 9/4/2019 entitled "differential pressure sensor package and electronic device," the entire contents of which are hereby incorporated by reference.

Technical Field

The utility model relates to a sensor technical field especially relates to a sensor packaging structure.

Background

At present, in electronic equipment requiring detection of air pressure difference, in the prior art, two air pressure sensors are usually placed on a PCB of the electronic equipment, and whether the pressure difference reaches a threshold value is determined after processing the pressure difference value of the two air pressure sensors, so as to realize detection of the air pressure difference.

The use of two air pressure sensors results in increased cost of the electronic device; the two air pressure sensors occupy larger space to influence the shortening design of the product; moreover, the two air pressure sensors have strong mutual dependency, and the damage of any one of the two air pressure sensors can cause the failure of the whole product, so that the failure risk of the electronic equipment is large.

Therefore, a differential pressure sensor with high detection accuracy and high reliability is required to detect the air pressure difference.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a sensor packaging structure and electronic equipment are provided, improve the detection accuracy of sensor and electronic equipment's reliability.

In order to solve the above problem, the utility model provides a sensor packaging structure, include: the substrate is provided with a first surface and a second surface which are opposite, the edge of the shell is fixed on the first surface of the substrate, and a first cavity is formed between the shell and the substrate; the pressure sensing element is fixed on the first surface of the substrate and is positioned in the first cavity, the pressure sensing element is provided with a second cavity and a pressure sensing layer, and the pressure sensing layer is positioned between the first cavity and the second cavity; the first cavity is communicated with the outside through a first through hole, and the second cavity is communicated with the outside through a second through hole.

Optionally, the first through hole penetrates through the housing; the second through hole penetrates through the substrate.

Optionally, the first through hole and the second through hole both penetrate through the substrate.

Optionally, the first through hole and the second through hole are located on two opposite sides or the same side of the differential pressure sensor package structure.

Optionally, the integrated circuit further includes an application specific integrated circuit chip fixed to the first surface of the substrate located in the first cavity; the application specific integrated circuit chip is connected to the detection signal output end of the pressure sensing element and used for calculating a differential pressure value according to the detection signal output by the pressure sensing element.

Optionally, the surface of the asic chip is covered with a protective layer.

Optionally, the asic chip is configured to output a feedback signal when the calculated voltage difference value reaches a threshold value.

Optionally, a sealing area is formed on the second surface of the substrate, the sealing area is a closed graph, and a projection of the second through hole on a plane where the sealing area is located in the closed graph.

Optionally, the sealing region at least partially protrudes from, is flush with, or is lower than the second surface of the substrate.

Optionally, the sealing region comprises a conductive ring or an insulating ring.

The utility model discloses a sensor packaging structure only has a pressure sensing element, pressure sensing element's pressure sensing layer is located between first cavity and the second cavity, first cavity and second cavity have respectively into the through-hole, consequently, can detect the pressure differential between first cavity and the second cavity through single pressure sensing element. And only one pressure sensing element is arranged, so that the packaging structure is simple, the size is small and the cost is low.

Further, the sensor package structure further includes an asic chip for calculating a differential pressure value according to a detection signal of the pressure sensing element. Because the power consumption of the asic chip is low, the power consumption can be reduced compared to calculating the differential pressure value using a device processor.

Drawings

Fig. 1 is a schematic structural diagram of a sensor package structure according to a first embodiment of the present invention;

fig. 2 is a pressure sensing element of a sensor package structure according to a first embodiment of the present invention;

fig. 3 is a schematic second surface view of the substrate of the sensor package structure according to the first embodiment of the present invention;

fig. 4 is a schematic structural diagram of a sensor package structure according to a second embodiment of the present invention;

fig. 5 is a schematic structural diagram of a sensor package structure according to a third embodiment of the present invention;

fig. 6 is a schematic structural diagram of a sensor package structure according to a fourth embodiment of the present invention.

Detailed Description

The following describes embodiments of the sensor package structure in detail with reference to the accompanying drawings.

First embodiment

Fig. 1 is a schematic cross-sectional view of a sensor package structure according to an embodiment of the present invention.

The sensor packaging structure is a differential pressure sensor packaging structure, including: a substrate 11 and a housing 1, the substrate 11 having a first surface and a second surface opposite to each other. The first surface is used for fixing the sensor, and the second surface is used for connecting to other circuit boards. The edge of the housing 1 is fixed on the first surface of the substrate 11, and a first cavity 6 is formed between the housing and the substrate 11.

The substrate 11 may be made of a conventional substrate material such as RF-4, BT or ceramic substrate. The substrate 11 may have solder pads or electrical connection structures formed thereon for providing electrical connection points. The substrate 11 may be a single-layer or multi-layer circuit board, and a circuit structure or an electrical contact portion, such as a pad, may be formed on the surface of the substrate 11; the substrate 11 may further have an electrical connection structure formed therein for connecting electrical contacts of the first surface and the second surface of the substrate 11.

The housing 1 serves as a packaging housing of the differential pressure sensor, and is used for protecting internal electronic elements, and a first cavity 6 is formed between the housing and the substrate 11. The shell 1 can be made of metal, is high-temperature resistant, is 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 housing 1 may also be made of other hard materials such as plastic, which is not limited herein.

The edge of the housing 1 is fixed to the first surface of the substrate 11 by welding or gluing, so that a first cavity 6 is formed between the housing 1 and the substrate 11. In this embodiment, the housing 1 has a first through hole 4 penetrating through the shell of the housing 1 so that the first cavity 6 communicates with the outside of the housing 1. The housing of the housing 1 has at least one first through hole 4. In this embodiment, the housing 1 has only 1 first through hole 4, and in other embodiments, the housing 1 may have more than two first through holes. The edge of the shell 1 is hermetically connected with the substrate 11, so that the first cavity 6 can only communicate with the outside through the first through hole 4, and gas in the first cavity 6 cannot leak at other positions.

The differential pressure sensor packaging structure further comprises a pressure sensing element 2 which is fixed on the surface of the substrate 11 and is positioned in the first cavity 6. The pressure sensing element 2 is an MEMS device, and has a second cavity 10 and a pressure sensing layer, and the pressure sensing layer is located between the first cavity 6 and the second cavity 10.

Fig. 2 is a schematic structural diagram of the pressure sensing element 2 of the electronic device in this embodiment.

The pressure sensing element 2 comprises the pressure sensing layer 201 and a supporting structure 202 for supporting the edge of the pressure sensing layer 201, and the second cavity 10 is located between the pressure sensing layer 201 and the supporting structure 202. The pressure sensing layer 201 of the pressure sensing element 2 may include a pressure sensitive film, the pressure sensitive film may be a semiconductor film layer formed with a plurality of piezoresistors 203, and the plurality of piezoresistors 203 form a wheatstone bridge structure. The pressure sensing layer 201 deforms under the action of pressure, and the resistance of the piezoresistor 203 changes, so that the output signal of the Wheatstone bridge changes.

In fig. 1 and 2, the pressure sensing element 2 is shown only as a schematic representation and does not represent the actual structure of the pressure sensing element 2. In other embodiments, the pressure sensing element 2 may also be other types of pressure sensing elements with cavities, for example, to detect pressure by a change in capacitance.

The substrate 11 has a second through hole 9, the second through hole 9 is communicated to the second cavity 10, and the second cavity is externally communicated through the second through hole 9. In this embodiment, only one second through hole 9 on the substrate 11 is communicated with the second cavity 10; in other embodiments, the substrate 11 may further have more than two second through holes communicating with the second cavity 10.

In this embodiment, the first through hole 4 and the second through hole 9 are located on two opposite sides of the differential pressure sensor package structure. In other embodiments, the positions of the first through hole 4, the second through hole 9 and the pressure sensing element 2 can be set reasonably according to actual detection requirements.

In this embodiment, the surface of the first through hole 4 is covered with a waterproof breathable film 3, which can prevent corrosive substances from entering the first cavity 6. In other embodiments, the waterproof breathable film may not be provided. The waterproof breathable film 3 can be made of hydrophobic materials, and specifically can be at least one of PP (polypropylene) spun-bonded non-woven fabric, PE high-molecular breathable film and PP spun-bonded non-woven fabric. In this embodiment, the waterproof breathable film 3 covers the outer surface of the outer shell 1, and in other embodiments, the waterproof breathable film 3' may also cover the inner surface of the outer shell 1.

In this embodiment, the differential pressure sensor package structure further includes an asic chip 5 located in the first cavity 6, and fixed on the surface of the substrate 11 located in the first cavity 6; the asic chip 5 is connected to a detection signal output terminal of the pressure sensor element 2, and is configured to calculate a differential pressure value from the detection signal output by the pressure sensor element 2.

Because the pressure sensing layer of the pressure sensing element 2 is located between the first cavity 6 and the second cavity 10, the gas pressures in the first cavity 6 and the second cavity 10 simultaneously act on the pressure sensing layer of the pressure sensing element 2, so that the finally received pressure of the pressure sensing layer is the pressure difference between the first cavity 6 and the second cavity 10, and thus the detection signal output by the pressure sensing element 2 corresponds to the pressure difference between the first cavity 6 and the second cavity 10, and then the detection signal output by the pressure sensing element 2 is calculated by the asic chip 5 to obtain the corresponding pressure difference value. Through one pressure sensing element 2 can detect the differential pressure value that obtains two through-hole positions department, need not to set up a plurality of pressure sensor in different through-hole positions department, can reduce the differential pressure and make the size of pressfitting sensor diminishes, practices thrift the cost. The integrated circuit chip 5 has high reliability and low power consumption in the calculation process, can save a large amount of power consumption and prolong the standby time of products.

The asic chip 5 is connected to the signal output terminal of the pressure sensor element 5 by gold wire bonding or other bonding processes, so as to calculate a differential pressure value from the detection signal output from the pressure sensor element 2.

In order to protect the asic chip 5 and the connecting wires between the asic chip and the pressure sensing element 5, in this embodiment, the asic chip 5 is further covered with a protective layer 15.

The asic chip 5 is configured to output a feedback signal when the voltage difference value reaches a threshold value, thereby avoiding output of an invalid signal and saving power consumption.

Fig. 3 is a schematic diagram of a second surface of the substrate 11 of the differential pressure sensor package structure.

The differential pressure sensor package structure further comprises a sealing area 7 and a weld pad 14 at the second surface of the substrate 11. The shape of the sealing area 7 is a closed figure, and specifically, can be a closed ring shape. The projection of the second through hole 9 on the plane of the sealing area 7 is located within the closed figure. In this embodiment, the sealing area 7 is circular. In other embodiments, the sealing area 7 may also be a closed figure such as a rectangle, a polygon or various irregular figures.

The sealing area 7 is used for fixedly connecting with the circuit board when the substrate 11 is connected to other circuit boards.

In this embodiment, the sealing area 7 includes a conductive ring, which can form an electrical connection between the substrate 11 and the first circuit board 12 while enabling the connection between the second through hole 9 and the third through hole, and can also serve as a Ground (GND) terminal in product performance.

The sealing area 7 may further include an insulating ring, such as epoxy resin, rubber, etc., which can achieve a good sealing effect.

In order to improve the sealing effect when the sealing region 7 is connected to other circuit boards, the sealing region 7 protrudes from the second surface of the substrate 11. In order to ensure that the sealing area 7 protrudes from the second surface of the substrate 11, the solder resist material on the surface of the solder resist area 13 of the substrate 11 at the edge of the sealing area 7, at least the solder resist area 13 of the substrate 11 located inside the sealing area 7, may be removed by polishing, etching or grinding, so that the surface of the solder resist area 13 is significantly lower than the sealing area 7. The solder resist material may be glass fiber or plastic on the surface of the substrate 11.

The differential pressure sensor package structure may be secured to a circuit board. Specifically, the differential pressure sensor package structure is fixed to the circuit board through the substrate 11. The circuit board is formed with a circuit and is electrically connected to the substrate 11. The asic chip 5 is electrically connected to the circuit board through electrical connection structures located in the substrate 11, and pads 14. The circuit board is formed with a functional circuit, and the signal output by the asic chip 5 is used as an input signal of the functional circuit on the circuit board. The functional circuit on the circuit board is capable of processing the signals output by the asic chip 5. In other embodiments, other electronic components may be mounted on the circuit board 12.

The first circuit board may have a third through hole, the third through hole is in sealed communication with the second through hole 9, and the second cavity 10 is in communication with the outside through the second through hole 9 and the third through hole. The third through hole is in sealed communication with the second through hole 9, so that when external air enters the second cavity 10 through the third through hole and the second through hole 9, the external air cannot leak from the space between the first circuit board 12 and the substrate 11, and the accuracy of differential pressure detection can be improved.

The second surface of the substrate 11 can be fixed on the circuit board through the sealing area 7 and the welding pad 14. The projections of the second through hole 9 and the third through hole on the plane of the sealing area 7 are both located in the closed graph, and the sealing area 7 is located between the substrate 11 and the circuit board, so that the third through hole is communicated with the second through hole 9.

The number and shape of the pads 14 are not limited in fig. 3, and may be set according to the specific circuit structure.

In this embodiment, the sealing region 7 is a circular solder ring, and the sealing region 7 and the solder pads 14 are electrically connected to a circuit on a circuit board through a soldering process to transmit signals.

In order to avoid leakage between the circuit board and the substrate 11 when liquid or gas enters the second through hole 9 from the third through hole of the circuit board, the third through hole is in sealed communication with the second through hole 9. The solder-resisting area 13 is obviously lower than the sealing area 7, so that the sealing area 7 can easily connect the substrate 11 and the circuit board together tightly through the sealing material, and the air tightness of the product is ensured. In other specific embodiments, the sealing region 7 may be connected to the first circuit board 12 by adhesive bonding, and in this case, a sealing material such as an adhesive layer is provided between the sealing region 7 and the circuit board, so that the sealing region 7 and the circuit board are connected in a sealing manner.

Besides the sealing connection between the sealing area 7 and the circuit board is formed by solder, glue, or the like, in other embodiments, the edge of the connection position between the sealing area 7 and the circuit board may be further filled with a sealing material such as solder, glue, or the like, so as to improve the sealing property between the sealing area 7 and the circuit board.

In other embodiments, the sealing region 7 may also be located in the surface of the substrate 11, at least partially below the second surface of the substrate 11 or flush with the second surface of the substrate 11, and the sealing connection between the sealing region 7 and the circuit board is achieved by filling a sealing material between and/or at the edge of the sealing region 7 and the circuit board.

Second embodiment

Please refer to fig. 4, which is a schematic structural diagram of a sensor package structure according to another embodiment of the present invention.

In this embodiment, the first through hole 4 of the housing 1 may be an open through hole without being covered with a waterproof film. The third through hole of the circuit board for fixing the packaging structure can be covered with a waterproof breathable film 3, and the waterproof breathable film can be covered on the outer side and the surface of the circuit board, which face away from the differential pressure sensor, and can also be covered on the inner side surface of the circuit board in other embodiments.

In general, the surface of the through-hole on the side where the air flow is applied may be covered with a waterproof and air-permeable film. In other implementations, the surfaces of the first through hole 4 and the third through hole on the two opposite sides of the differential pressure sensor can be covered with waterproof and breathable films.

In the above embodiments, the differential pressure sensor package structure may be disposed horizontally or vertically, and may detect a change in air pressure difference between above and below the differential pressure sensor.

Third embodiment

Referring to fig. 5, in this embodiment, the first cavity 6 of the differential pressure sensor package structure is communicated with the outside through the first through hole 4 a. The first through hole 4a penetrates through the substrate 11 and is communicated with the first cavity 6. In this embodiment, the air inlet or liquid inlet direction of the first through hole 4a is parallel to the surface of the substrate 11, and the air outlet or liquid outlet direction is perpendicular to the surface of the substrate 11.

When the electronic device is used, the first through hole 4a and the third through hole are respectively communicated to different external environments, that is, the pressure difference in the different external environments can be tested.

Fourth embodiment

Referring to fig. 6, in this embodiment, the first cavity 6 between the differential pressure sensor package structure housing 1 and the substrate 11 is communicated with the outside through the first through hole 4 b. The first through hole 4b penetrates through the substrate 11 and is communicated with the first cavity 6. In this embodiment, the first through hole 4b vertically penetrates the substrate 11, and is located outside the sealing region 7. The external gas or liquid enters the first cavity 6 through the first through hole 4b via the gap between the substrate 11 and the circuit board 12.

In the use process, the first through hole 4b and the third through hole are respectively communicated to different external environments, and therefore the pressure difference in the different external environments can be tested.

In other embodiments, the position of the first through hole can be reasonably set according to factors such as different external environment positions of the pressure difference to be measured.

Fifth embodiment

The signal output terminal of the asic chip of the differential pressure sensor may be connected to a processor (CPU) for obtaining an output signal of the asic chip and initiating a corresponding command according to the output signal.

The processor (CPU) can be attached to the circuit board of the fixed packaging structure and connected to the signal output end of the special integrated circuit chip through a functional circuit on the circuit board. In other specific embodiments, the processor may also be mounted on another circuit board, for example, a motherboard, and connected to the circuit board through an inter-board connection line, so as to implement signal connection with the signal output terminal of the asic chip, and implement signal transmission between the processor and the asic chip.

The application specific integrated circuit chip is configured to send a feedback signal to the processor when the differential pressure value detected by the pressure sensing element reaches a threshold value. When the differential pressure value does not reach the threshold value, the processor is in a standby stage without processing instructions related to the differential pressure value.

When the electronic equipment is in a standby state, the differential pressure sensor automatically detects the change of the pressure value at regular intervals. The pressure sensing element of the differential pressure sensor transmits a detection signal of pressure change to the special integrated circuit chip, the special integrated circuit chip calculates a pressure difference value, when the air pressure difference at two sides reaches a set threshold value, the pressure difference value is fed back to the processor, and the processor starts a related instruction. The processor may be in a standby state before the pressure differential value reaches a threshold value, reducing power consumption. Because the power consumption of the special integrated circuit chip is far less than that of the processor, the special integrated circuit chip is used for calculating the air pressure difference and feeding back the effective air pressure difference value to the processor, so that the power consumption of the electronic equipment can be saved, and the standby time of the equipment can be prolonged. The electronic equipment is simple in structure and can be produced in large scale.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A sensor package structure, comprising:

the substrate is provided with a first surface and a second surface which are opposite, the edge of the shell is fixed on the first surface of the substrate, and a first cavity is formed between the shell and the substrate;

the pressure sensing element is fixed on the first surface of the substrate and is positioned in the first cavity, the pressure sensing element is provided with a second cavity and a pressure sensing layer, and the pressure sensing layer is positioned between the first cavity and the second cavity;

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

2. The sensor package structure of claim 1, wherein the first through hole extends through the housing; the second through hole penetrates through the substrate.

3. The sensor package structure of claim 1, wherein the first and second vias each extend through the substrate.

4. The sensor package structure of claim 1, wherein the first via and the second via are located on opposite sides or the same side of the sensor package structure.

5. The sensor package structure of claim 1, further comprising an application specific integrated circuit chip secured to the first surface of the substrate within the first cavity; the application specific integrated circuit chip is connected to the detection signal output end of the pressure sensing element and used for calculating a differential pressure value according to the detection signal output by the pressure sensing element.

6. The sensor package structure of claim 5, wherein the ASIC chip surface is covered with a protective layer.

7. The sensor package structure of claim 5, wherein the application specific integrated circuit chip is configured to output a feedback signal when the calculated differential pressure value reaches a threshold value.

8. The sensor package structure of claim 1, wherein a sealing region is formed on the second surface of the substrate, the sealing region is a closed pattern, and a projection of the second through hole on a plane of the sealing region is located in the closed pattern.

9. The sensor package structure of claim 8, wherein the sealing region at least partially protrudes above, is flush with, or is below the second surface of the substrate.

10. The sensor package of claim 8, wherein the sealing region comprises a conductive ring or an insulating ring.

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