CN115278417A

CN115278417A - Vibration sensor and sensor packaging process

Info

Publication number: CN115278417A
Application number: CN202210588534.5A
Authority: CN
Inventors: 阎堂柳; 毕训训; 裴振伟; 端木鲁玉
Original assignee: Weifang Goertek Microelectronics Co Ltd
Current assignee: Weifang Goertek Microelectronics Co Ltd
Priority date: 2022-05-26
Filing date: 2022-05-26
Publication date: 2022-11-01

Abstract

The embodiment of the application discloses a vibration sensor and a sensor packaging process, wherein the vibration sensor comprises a substrate, a chip unit and a shell, the chip unit is arranged on the substrate, the shell is covered on the periphery of the chip unit and is in sealing connection with the substrate, and an inner cavity is formed between the shell and the substrate; the base plate is provided with a gas release hole, and the gas release hole is configured to communicate the inner cavity with the external environment; one side of the substrate, which is far away from the chip unit, is provided with an air hole pad, and the air hole pad surrounds the air leakage hole. The technical effect of the embodiment of the application lies in that the air leakage hole is formed in the substrate, and in the process of assembling the sensor on the whole machine, the air leakage hole is blocked while the substrate is in welded connection with the whole machine, so that the extra procedure of blocking the air leakage hole of the sensor is saved, the time and the cost are saved, and the process is simplified.

Description

Vibration sensor and sensor packaging process

Technical Field

The application belongs to the technical field of sensors, and particularly relates to a vibration sensor and a sensor packaging process.

Background

The vibration sensor is used for sensing external vibration or pressure signals, for example, the vibration sensor can be used for picking up bone vibration signals during speaking, and the vibration sensor is used as a bone voiceprint sensor to be applied to electronic products such as TWS earphones and the like.

In order to prevent the increase of the internal air pressure of the product and the damage of components caused by the heating curing process in the sensor packaging process, air leakage holes are usually left on the shell in the prior art.

The vibration sensor picks up vibration signals in the application process, and the existence of the air leakage hole can cause external environment noise to enter a product to cause gas disturbance, introduce noise, reduce the picking-up precision of the vibration signals and greatly influence the normal use of devices. Consequently, after assembling the sensor to the complete machine, need carry out the stifled hole operation, avoid external environment noise to introduce, but this stifled hole process can lead to the fact additional process, increase cost to the product application.

Disclosure of Invention

An object of the embodiments of the present application is to provide a new technical solution for a vibration sensor and a sensor packaging process.

According to a first aspect of the embodiments of the present application, there is provided a vibration sensor, including a substrate, a chip unit disposed on the substrate, and a housing covering the chip unit and hermetically connected to the substrate, wherein an inner cavity is formed between the housing and the substrate;

the base plate is provided with a gas release hole, and the gas release hole is configured to communicate the inner cavity with the external environment;

one side of the substrate, which is far away from the chip unit, is provided with an air hole pad, and the air hole pad surrounds the air leakage hole.

Optionally, the diameter of the air leakage hole is less than 0.2mm.

Optionally, the air leakage hole is disposed in a projection range of the chip unit on the substrate.

Optionally, a gap is provided between the air hole pad and the air release hole.

Optionally, the substrate is provided with a barrier layer within the gap.

Optionally, the barrier layer width is greater than 0.15mm.

Optionally, the air hole pad is disposed on the substrate.

Optionally, a ground pad is disposed on a side surface of the substrate away from the housing, and the air hole pad is disposed on the ground pad.

According to a second aspect of the embodiments of the present application, there is also provided a sensor packaging process, including the steps of:

providing a substrate, a chip unit and a shell, wherein the substrate is provided with a first surface and a second surface which are arranged in an opposite way, an air leakage hole penetrating through the substrate is formed in the substrate, an air hole bonding pad surrounding the air leakage hole is arranged on the first surface of the substrate, and a gap is formed between the air hole bonding pad and the air leakage hole;

installing the chip unit on the second surface of the substrate through colloid and the like, buckling the shell on the periphery of the chip unit, and hermetically connecting the shell and the substrate through the colloid to obtain an assembled sensor;

the solder paste is coated on the air hole bonding pad, the assembled sensor is placed at a required position for welding, and when a product reflows, the solder paste can be fully distributed on the whole air hole bonding pad to connect the air hole bonding pad with the circuit board, and meanwhile, the air leakage hole is firmly sealed.

Optionally, a barrier layer is applied at spaced locations between the air hole pads and the air release holes.

One technical effect of the embodiment of the application is as follows: through seting up the disappointing hole on the base plate, be favorable to guaranteeing vibration sensor's inside and outside atmospheric pressure balance, it leads to the inside atmospheric pressure increase of product to the influence of sensor to reduce encapsulation in-process heating curing process, furthermore, at the in-process of sensor assembly on the complete machine, the disappointing hole of shutoff when base plate and complete machine welded connection, save the extravagant hole process of shutoff of sensor, it is directly sealed with disappointing hole when welding the sensor on the complete machine, time and cost are saved, the process is simplified.

Further features of the present application and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which is to be read in connection with the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and together with the description, serve to explain the principles of the application.

Fig. 1 is a schematic cross-sectional structural diagram of a vibration sensor provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a substrate according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of another substrate according to an embodiment of the present disclosure.

Wherein: 1. a substrate; 2. a chip unit; 21. a vibration pickup unit; 22. a support housing; 23. processing the chip; 3. a housing; 4. an inner cavity; 5. an air release hole; 6. a gas hole pad; 7. a barrier layer; 8. a ground pad; 9. and connecting the bonding pads.

Detailed Description

Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the prior art, the vibration sensor includes a substrate, a chip unit, a housing, and other components, and the components are bonded by glue or solder paste, which inevitably has a thermal curing or reflow process. This process can cause the inside air heat of product to rise, if can not in time carry out the action of exhausting, the increase of inside atmospheric pressure can destroy the part, also can cause the part between can not steadily assemble, leads to the product to become invalid.

In order to avoid the damage of the device caused by the expansion of hot gas to the closed cavity in the packaging process of the vibration sensor, a closed space cannot be formed when the packaging process of the vibration sensor is produced, so that a gas leakage hole is reserved on the shell, and the gas leakage hole is also used for performing gas leakage when the internal gas expands due to the welding of tin paste when a product is used.

However, the vibration sensor picks up the vibration signal in the use process, and the existence of the air leakage hole can cause external environment noise to enter the vibration sensor to cause gas disturbance and introduce noise, so that the picking-up precision of the vibration sensor on the vibration signal is reduced, and the normal use of the vibration sensor is greatly influenced.

Consequently, after assembling vibration sensor to the complete machine, need to carry out the stifled hole operation to the disappointing hole on the shell, avoid external environment noise to introduce. In the prior art, the hole plugging mode is various, such as the sealing by adhering an isolating film or glue. However, this plugging process can result in additional processing steps for product application and increased costs.

In view of the above, the present application provides a vibration sensor.

Referring to fig. 1 to 3, the vibration sensor includes a substrate 1, a chip unit 2, and a housing 3, the chip unit 2 is disposed on the substrate 1, the housing 3 covers the periphery of the chip unit 2 and is hermetically connected to the substrate 1, and an inner cavity 4 is formed between the housing 3 and the substrate 1. Specifically, referring to fig. 1, the chip unit 2 includes a vibration pickup unit 21 adhered to the upper surface of the substrate 1, a support shell 22 is adhered to a surface of the vibration pickup unit 21 on a side away from the substrate 1, that is, the support shell 22 is adhered to the upper surface of the vibration pickup unit 21, and two processing chips 23 arranged side by side are adhered above the support shell 22. An inner cavity 4 is formed between the shell 3 and the substrate 1, the inner cavity 4 comprises a space between the chip unit 2 and the shell, and also comprises a space between the substrate 1 and the processing chip 23, a supporting shell 22 and the vibration pickup unit 21, and the air in the whole inner cavity 4 is communicated.

The base plate 1 is provided with a gas release hole 5, and the gas release hole 5 is configured to communicate the inner cavity 4 with the external environment. The air release hole 5 is a through hole penetrating through the substrate 1, and the air in the inner cavity 4 is communicated with the external environment through the air release hole 5, so that the balance of the air pressure in the inner cavity 4 is realized. The present application does not limit the position of the air release holes 5 on the substrate 1, and does not limit the shape, size and number of the air release holes 5.

One side of the substrate 1, which is far away from the chip unit 2, is provided with an air hole pad 6, and the air hole pad 6 is arranged around the air leakage hole 5. The air hole bonding pad 6 provides a space for the solder paste used in the subsequent welding, so that the solder paste is convenient to be fully distributed with the air hole bonding pad 6 when reflowing, and when the vibration sensor is connected with the whole machine, firm sealing of the air leakage hole 5 is realized.

According to the vibration sensor, the air leakage hole 5 is formed in the substrate 1, so that balance between internal air pressure and external air pressure of the vibration sensor in the packaging process is realized, and the influence of the increase of the internal air pressure of a product on the sensor caused by the heating and curing process in the packaging process is reduced; on the other hand, in the process that the sensor is assembled on the whole machine, the base plate 1 is welded with the whole machine and simultaneously blocks the air leakage hole 5, the process of blocking the air leakage hole 5 additionally for the sensor is omitted, the air leakage hole 5 is directly sealed when the sensor is welded on the whole machine, the time and the cost are saved, and the process is simplified.

Optionally, the diameter of the relief holes 5 is less than 0.2mm. In the embodiment of the present application, one air release hole 5 is provided, and the diameter of the air release hole 5 is less than 0.2mm.

Because the air release hole 5 is still in the open state after the vibration sensor is packaged, the air release hole 5 can not be plugged until the vibration sensor is installed on the whole machine. Therefore, the diameter of the air leakage hole 5 is too large, which easily causes foreign matters such as external dust to enter the inner cavity 4 of the vibration sensor, and influences the performance of the vibration sensor. The diameter of the air leakage hole 5 in the application is less than 0.2mm, so that the possibility that external impurities enter the inner cavity 4 can be reduced when the balance of the inner cavity 4 and the ambient air pressure is realized, and the performance of the vibration sensor is improved.

Alternatively, the air escape hole 5 is provided in a projection range of the chip unit 2 on the substrate 1. Referring to fig. 1, a chip unit 2 is mounted at a central position of a substrate 1, a gas release hole 5 is opened in a projection range of the chip unit 2 in a direction perpendicular to a plane of the substrate 1, and the gas release hole 5 is disposed at the central position of the substrate 1 of the chip unit 2.

In the embodiment of the present application, an inner cavity 4 is formed between the outer shell 3 and the substrate 1, the inner cavity 4 includes a space between the chip unit 2 and the housing, and also includes a space between the substrate 1 and the processing chip 23, the supporting shell 22 and the vibration pickup unit 21, and the air in the whole inner cavity 4 is communicated with each other. Compare and seting up out the projection scope of chip unit 2 on base plate 1 with disappointing hole 5, set up in the projection scope of chip unit 2 on base plate 1 disappointing hole 5 in this application, be favorable to realizing the abundant flow of the gas in inner chamber 4, especially drive the gas between the chip unit 2 and flow to improve the flow efficiency of gas in inner chamber 4, realize the gas pressure in the different regions in the inner chamber 4 balanced.

Optionally, a gap is provided between the air hole pad 6 and the air release hole 5. Referring to fig. 2, the air hole pad 6 is not directly attached to the air release hole 5, the air hole pad 6 is annular, and the inner diameter of the air hole pad 6 is larger than the outer diameter of the air release hole 5.

Be provided with the clearance between gas pocket pad 6 and the hole of disappointing 5, this clearance department is naked base plate 1, because the difficult attached to on base plate 1 of tin cream to be favorable to preventing that the tin cream from this hole of disappointing 5 positions from flowing into inner chamber 4, influence vibration sensor internal performance. And then realize when guaranteeing to carry out the shutoff with disappointing hole 5, can also prevent that the tin cream from going into inner chamber 4 through disappointing hole 5, guarantee vibration sensor's internal performance.

Optionally, the substrate 1 is provided with a barrier layer 7 within the gap. The barrier layer 7 is disposed on a side of the substrate 1 away from the chip unit 2, that is, a lower surface of the substrate 1 shown in fig. 1. In the embodiment of the present application, the barrier layer 7 may be formed by spraying ink, and solder paste is not easily attached to the ink surface.

The barrier layer 7 is arranged at the gap position of the substrate 1, so that the barrier effect on the solder paste is enhanced, the solder paste is further prevented from flowing into the air leakage hole 5, and the performance of the vibration sensor is ensured.

Optionally, the barrier layer 7 is wider than 0.15mm. Referring to fig. 2, the barrier layer 7 in the embodiment of the present application may be configured in a ring shape with the same width of each portion, and the minimum width of the barrier layer 7 is 0.15mm. Further, the barrier layer 7 may be provided in a ring shape having different widths of the respective portions, wherein a minimum distance between an inner diameter of the land and an outer diameter of the air escape hole 5 is 0.15mm.

If the width of the barrier layer 7 is too small, the barrier layer 7 has a poor effect on blocking solder paste, but if the width of the barrier layer 7 is too large, more solder paste is required to block the air leakage hole 5, which increases the processing cost.

Alternatively, the air hole pads 6 are provided on the substrate 1. Referring to fig. 1, the air hole pads 6 are disposed on a side of the substrate 1 away from the chip unit 2, that is, a lower surface of the substrate 1 in fig. 1. The lower surface of the substrate 1 is also provided with connection pads 9 for electrical connection with the chip unit 2, and ground pads 8 for connection with a ground line. In this embodiment, the number of the connection pads 9 is three, the number of the ground pads 8 is three, and the air hole pads 6 are provided separately from the connection pads 9 and the ground pads 8 and are independent of each other.

With gas pocket pad 6 and connecting pad 9, ground connection pad 8 separately setting, the position and the size of the accurate control gas pocket pad 6 of being convenient for to improve the accuracy of the disappointing hole 5 of tin cream shutoff, realize disappointing hole 5's abundant sealing when reducing the tin cream loss.

Alternatively, the surface of the substrate 1 on the side away from the case 3 is provided with a ground pad 8, and the air hole pad 6 is provided on the ground pad 8. Referring to fig. 3, a plurality of ground pads 8 are connected in the lower surface of the substrate 1, and one larger ground pad 8 is formed, that is, the ground pad 8 is provided as a whole. The lower surface of the substrate 1 is further provided with three connection pads 9 for electrical connection with the chip unit 2.

The air leakage hole 5 in the embodiment of the present application is located on the ground pad 8, the ground pad 8 is designed to be a larger pad, and the air hole pad 6 is disposed on the ground pad 8. Wherein, gas pocket pad 6 and ground connection pad 8 body coupling, whole ground connection pad 8 encircles the setting of disappointing hole 5, and has the clearance between ground connection pad 8 and the hole 5 that loses heart. Through this setting, when welding vibration sensor, only need draw the tin cream on a ground connection pad 8, can realize the welding of ground connection pad 8 when the backward flow, the disappointing hole 5 of shutoff simultaneously. Compared with the air hole bonding pad 6 and the grounding bonding pad 8 which are separately arranged, the processing steps are favorably reduced, and the processing efficiency is improved.

The application also provides a sensor packaging process, which comprises the following steps:

providing a substrate 1, a chip unit 2 and a housing 3, wherein the substrate 1 has a first surface and a second surface opposite to each other, and referring to fig. 1, the first surface of the substrate 1 is a lower surface of the substrate 1, and the second surface of the substrate 1 is an upper surface of the substrate 1. Set up the disappointing hole 5 that runs through base plate 1 on base plate 1, the first surface of base plate 1 is provided with the gas pocket pad 6 that encircles disappointing hole 5, is provided with the interval between gas pocket pad 6 and the disappointing hole 5.

Bonding chip unit 2 in the second surface of base plate 1 through the colloid, detaining shell 3 and establishing in chip unit 2 periphery, shell 3 passes through colloid sealing connection with base plate 1, obtains the sensor after the equipment.

Coating tin cream on gas pocket pad 6, placing the sensor after will assembling in required position, welding, when the product backward flow, whole gas pocket pad 6 can be covered with to the tin cream, is connected gas pocket pad 6 and circuit board, and the hole 5 that will lose heart simultaneously is firmly sealed.

Optionally, a barrier layer 7 is applied at the spaced location between the air hole pad 6 and the air escape hole 5. The barrier layer 7 may be ink and applied to the spaced locations by spraying.

Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims

1. The vibration sensor is characterized by comprising a substrate (1), a chip unit (2) and a shell (3), wherein the chip unit (2) is arranged on the substrate (1), the shell (3) covers the periphery of the chip unit (2) and is hermetically connected with the substrate (1), and an inner cavity (4) is formed between the shell (3) and the substrate (1);

the base plate (1) is provided with a gas release hole (5), and the gas release hole (5) is configured to communicate the inner cavity (4) with the external environment;

keep away from in base plate (1) one side of chip unit (2) is provided with air vent pad (6), air vent pad (6) encircle the setting of disappointing hole (5).

2. Vibration sensor according to claim 1, characterized in that the diameter of the air-escape aperture (5) is less than 0.2mm.

3. The vibration sensor according to claim 1, characterized in that the air-escape hole (5) is provided in a projection range of the chip unit (2) on the substrate (1).

4. The vibration sensor according to claim 1, wherein a gap is provided between the air hole pad (6) and the air escape hole (5).

5. The vibration sensor according to claim 4, characterized in that the substrate (1) is provided with a barrier layer (7) in the gap.

6. Vibrating sensor according to claim 5, characterised in that the barrier layer (7) has a width greater than 0.15mm.

7. The vibration sensor according to claim 1, wherein the air hole pads (6) are provided on the substrate (1).

8. The vibration sensor according to claim 1, wherein a surface of the substrate (1) on a side away from the case (3) is provided with a ground pad (8), and the air hole pad (6) is provided on the ground pad (8).

9. A sensor packaging process, comprising the steps of:

providing a substrate (1), a chip unit (2) and a shell (3), wherein the substrate (1) is provided with a first surface and a second surface which are arranged in a back-to-back manner, an air leakage hole (5) penetrating through the substrate (1) is formed in the substrate (1), an air hole pad (6) surrounding the air leakage hole (5) is arranged on the first surface of the substrate (1), and a gap is formed between the air hole pad (6) and the air leakage hole (5);

installing the chip unit (2) on the second surface of the substrate (1) through colloid and the like, buckling the shell (3) on the periphery of the chip unit (2), and hermetically connecting the shell (3) and the substrate (1) through the colloid to obtain an assembled sensor;

coating tin cream on gas pocket pad (6), placing the sensor after will assembling in required position, welding, when the product backward flow, whole gas pocket pad (6) can be covered with to the tin cream, is connected gas pocket pad (6) and circuit board, and the hole (5) that will lose heart simultaneously firmly seals.

10. The sensor packaging process according to claim 9, characterized in that a barrier layer (7) is applied at the spacing between the air hole pad (6) and the air release hole (5).