CN213679812U

CN213679812U - Pressure module

Info

Publication number: CN213679812U
Application number: CN202022500910.XU
Authority: CN
Inventors: 缪建民; 潘孝江; 尹长通
Original assignee: Sv Senstech Wuxi Co ltd
Current assignee: Sv Senstech Wuxi Co ltd
Priority date: 2020-11-02
Filing date: 2020-11-02
Publication date: 2021-07-13
Anticipated expiration: 2030-11-02

Abstract

The embodiment of the utility model discloses pressure module. The pressure module includes: the circuit board comprises a circuit substrate, an MEMS chip, an ASIC chip, a first packaging circuit board, a pouring sealant and a second packaging circuit board. The utility model provides a technical scheme, fuse MEMS chip and ASIC chip together and set up in circuit substrate, first packaging circuit board and second packaging circuit board constitute in the cavity, and adopt the casting glue to fill, realize the purpose that the chip seal is not revealed, and can ensure under big pressure, MEMS chip and ASIC chip are undamaged and the bonding department does not fall off, improve whole compactness of structure, in addition, the pressure sensing component is only done to MEMS chip and ASIC chip, the reliability and the stability of product have been improved, the cost of pressure module is reduced and can make assembly cost, realize extensive automated production.

Description

Pressure module

Technical Field

The embodiment of the utility model provides a technical field who relates to semiconductor chip encapsulation especially relates to a pressure module.

Background

Micro-Electro-Mechanical Systems (MEMS for short) is a process technology that combines Micro-electronic technology and Mechanical engineering, and its operating range is in the micrometer range. MEMS is a new field of development that must simultaneously take into account the mixed action of various physical fields, and their size is smaller, up to a maximum of one centimeter, and even a few micrometers, and their thickness is even smaller than conventional machines. Application Specific Integrated Circuits (ASICs) are considered to be a special purpose designed Integrated Circuit in the Integrated Circuit community.

The packaging structure of the package of the MEMS chip and the ASIC chip opens up a brand new technical field and industry, and the microsensor and the like manufactured based on the packaging structure have very wide application prospect in all fields which people can contact.

In the prior art, the package structure of the MEMS chip and the ASIC chip in a general sensor module is directly fixed by bonding or welding the two relatively through a glue layer, so that the sensor module can cause the situation of chip sealing leakage in the using process, and particularly, the situation of MEMS chip damage easily occurs under the condition of large working pressure, and the MEMS chip cannot bear large pressure to cause bonding falling, and can be accompanied with the possibility of signal interruption, which affects the reliability of the system, and the subsequent maintenance cost is too high.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides a pressure module to improve the stability of the compressive capacity of chip and system, reduce sensor module manufacturing cost.

In a first aspect, an embodiment of the present invention provides a pressure module, including:

the circuit board comprises a circuit substrate, wherein a first surface of the circuit substrate is provided with an air inlet and a plurality of first welding discs;

the MEMS chip is bound on a second surface, opposite to the first surface, of the circuit substrate and covers the air inlet hole, and the MEMS chip is electrically connected with the first bonding pad;

an ASIC chip bonded on the second surface of the circuit substrate, the ASIC chip being electrically connected with the MEMS chip;

a first package circuit board, which is ring-shaped, is located on the second surface of the circuit substrate, and is disposed around the MEMS chip and the ASIC chip;

the pouring sealant is filled in the inner side of the first packaging circuit board and covers the MEMS chip and the ASIC chip;

the second packaging circuit board is positioned on one side, away from the circuit substrate, of the first packaging circuit board, a plurality of second bonding pads are arranged on the surface of one side, away from the circuit substrate, of the second packaging circuit board, and the second bonding pads are electrically connected with the ASIC chip;

the air inlet hole is used for enabling acting force to enter from the air inlet direction of the back, the MEMS chip is stressed to change through the MEMS chip above the air inlet hole, a pressure signal is generated, the ASIC chip amplifies the pressure signal, converts the pressure signal into a voltage signal and then transmits the voltage signal to an external circuit.

Optionally, the pressure module further includes a side lead, the first pad and the second pad correspond to each other one by one, and the first pad and the corresponding second pad are electrically connected through the side lead;

the interconnection wiring on the wiring substrate is electrically connected to the side leads.

Optionally, a plurality of extraction electrodes are further disposed on the surface of the second package circuit board, where the second pads are disposed, the extraction electrodes are electrically connected to the second pads in a one-to-one correspondence manner, and the extraction electrodes are used for outputting test signals.

Optionally, the circuit substrate, the first package circuit board, and the second package circuit board are made of ceramic or glass.

Optionally, the second package circuit board and the first package circuit board are bonded by epoxy glue, and the first package circuit board and the circuit substrate are bonded by epoxy glue.

Optionally, the potting adhesive is made of epoxy resin, organic silicon resin or polyurethane.

The pressure module provided by the embodiment of the utility model comprises a circuit substrate, an MEMS chip, an ASIC chip, a first packaging circuit board, a pouring sealant and a second packaging circuit board, wherein, the first surface of the circuit substrate is provided with an air inlet hole and a plurality of first bonding pads, the MEMS chip is bound on the second surface opposite to the first surface in the circuit substrate and covers the air inlet hole, the MEMS chip is electrically connected with the first bonding pads, the ASIC chip is bound on the second surface of the circuit substrate, the ASIC chip is electrically connected with the MEMS chip, the first packaging circuit board is annular, the first packaging circuit board is positioned on the second surface of the circuit substrate and is arranged around the MEMS chip and the ASIC chip, the pouring sealant is filled in the inner side of the first packaging circuit board and coats the MEMS chip and the ASIC chip, the second packaging circuit board is positioned on one side of the first packaging circuit board far away from the circuit substrate, a plurality of second bonding pads are arranged on one side surface of the second packaging circuit board far, the second bonding pad is electrically connected with the ASIC chip, wherein the air inlet hole is used for acting force to enter from the air inlet direction at the back, the MEMS chip is stressed and changed through the MEMS chip above the air inlet hole to generate a pressure signal, the ASIC chip amplifies the pressure signal and converts the pressure signal into a voltage signal to be transmitted to an external circuit, so that a client can conveniently obtain a test signal, the MEMS chip and the ASIC chip are fused together and arranged in a cavity formed by the circuit substrate, the first packaging circuit board and the second packaging circuit board, and the encapsulation glue is adopted for filling, the purpose of sealing the chip without leakage is realized, the MEMS chip and the ASIC chip are ensured to be undamaged and bonding parts are not dropped under large pressure, the compactness of the whole structure is improved, in addition, the MEMS chip and the ASIC chip are only used as pressure sensing elements, the reliability and the stability of a product are improved, and the cost and the manufacturable, realizing large-scale automatic production.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

fig. 1 is a schematic structural diagram of a pressure module according to an embodiment of the present invention;

fig. 2 is a side view of a pressure module according to an embodiment of the present invention;

fig. 3 is a bottom view of a pressure module according to an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view taken along the dashed line AB in FIG. 3;

fig. 5 is a top view of a pressure module according to an embodiment of the present invention;

fig. 6 is a schematic flow chart of a manufacturing method of a pressure module according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the following describes in detail specific embodiments of the present invention with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.

It should be further noted that, for the convenience of description, only some but not all of the relevant portions of the present invention are shown in the drawings. Before discussing exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart may describe the operations (or steps) as a sequential process, many of the operations can be performed in parallel, concurrently or simultaneously. In addition, the order of the operations may be re-arranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, and the like.

Fig. 1 is a schematic structural diagram of a pressure module according to an embodiment of the present invention. As shown in fig. 1, the pressure module includes: the circuit board comprises a circuit substrate 110, a MEMS chip 120, an ASIC chip 130, a first packaging circuit board 140, a pouring sealant 150 and a second packaging circuit board 160, wherein the first surface S1 of the circuit substrate 110 is provided with an air inlet hole 170 and a plurality of first bonding pads 180, the MEMS chip 120 is bound on the second surface S2 of the circuit substrate 110 opposite to the first surface S1 and covers the air inlet hole 170, the MEMS chip 120 is electrically connected with the first bonding pads 180, the ASIC chip 130 is bound on the second surface S2 of the circuit substrate 110, the ASIC chip 130 is electrically connected with the MEMS chip 120, the first packaging circuit board 140 is annular, the first packaging circuit board 140 is located on the second surface S2 of the circuit substrate 110 and arranged around the MEMS chip 120 and the ASIC chip 130, the pouring sealant 150 is filled inside the first packaging circuit board 140 and coats the MEMS chip 120 and the ASIC chip 130, the second packaging circuit board 160 is located on the side, away from the circuit substrate 110, of the first packaging circuit board 140, the second packaging circuit board 160 is provided with a plurality of second pads 190 on a side surface away from the circuit substrate 110, the second pads 190 are electrically connected with the ASIC chip 130, wherein the air inlet holes 170 are used for allowing an acting force to enter from a back air inlet direction, the MEMS chip 120 above the air inlet holes 170 is stressed and changed to generate a pressure signal, and the ASIC chip 130 amplifies the pressure signal and converts the pressure signal into a voltage signal to be transmitted to an external circuit.

Among them, the MEMS chip is generally several millimeters or less in size, and is an independent intelligent system. In the industry, when a single MEMS chip 120 is used to package a mechanical sensor, the integrated ASIC chip 130 controls the MEMS chip 120 and converts analog signals into digital signals.

It should be noted that the MEMS chip 120 is located on the second surface S2 of the circuit substrate 110 and covers the air inlet hole 170, in order to ensure that the acting force enters from the air inlet direction of the air inlet hole 170 and then completely acts on the MEMS chip 120, so that the back cavity of the MEMS chip 120 is stressed to change, the size of the aperture of the air inlet hole 170 is set to be smaller than the length of the back cavity of the MEMS chip 120, that is, the MEMS chip 120 needs to completely cover the air inlet hole 170, in addition, in order to ensure the accuracy of the acting force acting on the MEMS chip, the aperture of the air inlet hole 170 cannot be too small, and in the manufacturing process of the pressure module, the specific aperture size is designed by a.

Specifically, in the embodiment, the first package circuit board 140 is in an annular structure on the second surface S2 of the circuit substrate 110, and before the potting adhesive 150 is filled inside the first package circuit board 140, the first package circuit board 140 is adhered to the second surface S2 of the circuit substrate 110, so that the potting adhesive 150 can be better injected onto the MEMS chip 120 and the ASIC chip 130, and leakage is not caused. After the second package circuit board 160 is disposed on the side of the first package circuit board 140 away from the circuit substrate 110, the first package circuit board 140 and the second package circuit board 160 are bonded together, thereby completing the packaging of the entire pressure module. When the force in the air inlet hole 170 acts from the air inlet direction, the stress of the back cavity of the MEMS chip 120 changes, wherein the change of the stress of the back cavity of the MEMS chip 120 causes the change of the sensing film of the MEMS chip 120, and further causes the change of the internal resistance of the chip, because the MEMS chip 120 itself has a small volume, the change of the internal signal is generally in the millivolt level, the ASIC chip 130 electrically connected to the MEMS chip 120 receives the changed pressure signal and amplifies the pressure signal, and the amplified pressure signal is converted into a voltage signal and then output to the external circuit through the second bonding pad 190 electrically connected to the ASIC chip 130.

The present embodiments provide a pressure module, comprising: the circuit comprises a circuit substrate, an MEMS chip, an ASIC chip, a first packaging circuit board, a pouring sealant and a second packaging circuit board, wherein the first surface of the circuit substrate is provided with an air inlet hole and a plurality of first bonding pads, the MEMS chip is bound on the second surface of the circuit substrate opposite to the first surface and covers the air inlet hole, the MEMS chip is electrically connected with the first bonding pads, the ASIC chip is bound on the second surface of the circuit substrate, the ASIC chip is electrically connected with the MEMS chip, the first packaging circuit board is annular, the first packaging circuit board is positioned on the second surface of the circuit substrate and is arranged around the MEMS chip and the ASIC chip, the pouring sealant is filled in the inner side of the first packaging circuit board and coats the MEMS chip and the ASIC chip, the second packaging circuit board is positioned on one side of the first packaging circuit board, which is far away from the circuit substrate, and the surface of one side of the second packaging circuit board, which is far, the second bonding pad is electrically connected with the ASIC chip, wherein the air inlet hole is used for acting force to enter from the air inlet direction at the back, the MEMS chip is stressed and changed through the MEMS chip above the air inlet hole to generate a pressure signal, the ASIC chip amplifies the pressure signal and converts the pressure signal into a voltage signal to be transmitted to an external circuit, so that a client can conveniently obtain a test signal, the MEMS chip and the ASIC chip are fused together and arranged in a cavity formed by the circuit substrate, the first packaging circuit board and the second packaging circuit board, and the encapsulation glue is adopted for filling, the purpose of sealing the chip without leakage is realized, the MEMS chip and the ASIC chip are ensured to be undamaged and bonding parts are not dropped under large pressure, the compactness of the whole structure is improved, in addition, the MEMS chip and the ASIC chip are only used as pressure sensing elements, the reliability and the stability of a product are improved, and the cost and the manufacturable, realizing large-scale automatic production.

Optionally, fig. 2 is a side view of a pressure module according to an embodiment of the present invention. As shown in fig. 2, the pressure module further includes a side lead 210, the first pads 220 correspond to the second pads 230 one by one, the first pads 220 are electrically connected to the corresponding second pads 230 through the side lead 210, and fig. 3 is a bottom view of the pressure module according to an embodiment of the present invention. Fig. 4 is a schematic cross-sectional view along the dashed line AB in fig. 3. As shown in fig. 4, the interconnection lines 410 on the wiring substrate are electrically connected to the side leads 420.

Wherein, referring to fig. 2, the side leads 210 are bound at the left and right sides of the pressure module.

Specifically, with reference to fig. 3, a plurality of first pads 320 are disposed on the circuit substrate 310, such that the first pads 320 are electrically connected to the MEMS chip in the pressure module, and when a force acts from the air intake direction of the air intake hole 330, the force applied to the back cavity of the MEMS chip is changed to generate a pressure signal.

With continued reference to fig. 4, the ASIC chip electrically connected to the MEMS chip amplifies the pressure signal and transmits the amplified signal to the side lead 420 of the pressure module through the interconnection 410, and then transmits the amplified signal to the second bonding pad 440 on the upper surface of the second package circuit board 430, and the second bonding pad 440 can be connected to an external circuit, for example, a customer can use the bonding pad as a second bonding process to access the system to be operated, so as to implement the operation cycle of the entire pressure module.

Optionally, fig. 5 is a top view of a pressure module according to an embodiment of the present invention. As shown in fig. 5, a plurality of second pads 520 are disposed on the second package circuit board 510, so that the plurality of second pads 520 are electrically connected to the ASIC chip in the pressure module, a plurality of lead electrodes 530 are further disposed on the surfaces of the plurality of second pads 520, the lead electrodes 530 are electrically connected to the second pads 520 in a one-to-one correspondence, and the lead electrodes 530 are used for outputting test signals.

It should be noted that the second package circuit board 510 is used as the package circuit board at the outermost layer of the whole module, and a plurality of extraction electrodes 530 are disposed on the second package circuit board for outputting signals, in this embodiment, the length of the extraction electrodes 530 is not limited, as long as the extraction electrodes are within a range that allows a client to access a system under test, and referring to fig. 3, the extraction electrodes 530 may be rectangular, circular or other shapes, as long as the second pads 520 are disposed with protrusions.

Optionally, the substrate materials of the circuit substrate, the first package circuit board and the second package circuit board are both ceramic or glass.

It should be noted that, since the circuit substrate is provided with the interconnection circuit to be electrically connected to the side leads of the pressure module, and similarly, the first package circuit board and the second package circuit board are also provided with circuit lines for transmitting signals, in this embodiment, the circuit substrate, the substrates of the first package circuit board and the second package circuit board are partial structures except the interconnection circuit or the circuit lines, and the partial structures may be made of ceramic or glass, and may have an electrical insulation effect.

Optionally, the second package circuit board is bonded to the first package circuit board by epoxy glue, and the first package circuit board is bonded to the circuit substrate by epoxy glue.

Wherein, the epoxy glue is an excellent insulating material with high dielectric property, surface leakage resistance, electric arc resistance and strong adhesion. In this embodiment, first encapsulation circuit board passes through the epoxy glue and bonds on the second surface of circuit substrate, and after first encapsulation circuit board kept away from one side of circuit substrate and set up the second encapsulation circuit board, make first encapsulation circuit board and second encapsulation circuit board pass through the epoxy glue and bond, in view of the above, can ensure better that the casting glue pours into on MEMS chip and the ASIC chip, can not cause the wafer of chip to reveal, ensures whole pressure module's sealing performance.

Wherein, the casting glue is often used for electronic components's embedment, and in this embodiment, the casting glue can play dampproofing and waterproofing, dustproof, insulating, sealed, temperature resistant effect after the solidification to be liquid before the embedment, convenient to use, and the cost is lower.

Fig. 6 is a schematic flow chart of a manufacturing method of a pressure module according to an embodiment of the present invention. As shown in fig. 6, the manufacturing method specifically includes the following steps:

s610, providing a circuit substrate, wherein the first surface of the circuit substrate is provided with an air inlet hole and a plurality of first welding pads.

An air inlet hole is formed in the first surface of the circuit substrate by adopting a drilling process, the air inlet hole is located under the MEMS chip, and when acting force acts along the air inlet direction, the back cavity of the MEMS chip is stressed, and the ASIC chip integrated with the MEMS chip can better process signals.

S620, binding a MEMS chip on the first surface, wherein the MEMS chip covers the air inlet hole and is electrically connected with the first bonding pad.

And S630, binding an ASIC chip on the first surface, wherein the ASIC chip is electrically connected with the MEMS chip.

And S640, attaching a first packaging circuit board on the second surface, wherein the first packaging circuit board is annular and is arranged around the MEMS chip and the ASIC chip.

S650, filling a pouring sealant on the inner side of the first packaging circuit board by adopting a dispensing process, wherein the pouring sealant coats the MEMS chip and the ASIC chip.

The glue dispensing process is simple and reliable, has compact structure, can tightly fix the MEMS chip and the ASIC chip, enables the MEMS chip and the ASIC chip to be fused together and arranged in a cavity formed by the circuit substrate, the first packaging circuit board and the second packaging circuit board, and adopts the pouring sealant for filling, realizes the purpose of sealing the chip without leakage, and can ensure that the MEMS chip and the ASIC chip are not damaged and the bonding part does not fall off under high pressure, thereby improving the compactness of the whole structure.

And S360, attaching a second packaging circuit board to one side of the first packaging circuit board, which is far away from the circuit substrate, wherein a plurality of second bonding pads are arranged on the surface of one side of the second packaging circuit board, which is far away from the circuit substrate, and the second bonding pads are electrically connected with the ASIC chip.

The air inlet hole is used for enabling acting force to enter from the back air inlet direction, the MEMS chip is stressed to change through the MEMS chip above the air inlet hole, a pressure signal is generated, the ASIC chip amplifies the pressure signal, and the pressure signal is converted into a voltage signal and then transmitted to an external circuit.

According to the technical scheme provided by the embodiment, a circuit substrate is provided, a first surface of the circuit substrate is provided with an air inlet hole and a plurality of first bonding pads, an MEMS chip is bound on the first surface, the MEMS chip covers the air inlet hole and is electrically connected with the first bonding pads, an ASIC chip is bound on the first surface and is electrically connected with the MEMS chip, a first packaging circuit board is attached to a second surface, the first packaging circuit board is annular and is arranged around the MEMS chip and the ASIC chip, pouring sealant is filled in the inner side of the first packaging circuit board by adopting a dispensing process and coats the MEMS chip and the ASIC chip, a second packaging circuit board is attached to one side of the first packaging circuit board, which is far away from the circuit substrate, a plurality of second bonding pads are arranged on the surface of one side of the second packaging circuit board, which is far away from the circuit substrate, the second bonding pads are electrically connected with the ASIC chip, wherein the air inlet hole, the MEMS chip is stressed to change through the MEMS chip above the air inlet hole to generate a pressure signal, the ASIC chip amplifies the pressure signal and converts the pressure signal into a voltage signal to be transmitted to an external circuit, a client side can conveniently obtain a test signal, the MEMS chip and the ASIC chip are fused together and arranged in a cavity formed by the circuit substrate, the first packaging circuit board and the second packaging circuit board, and potting adhesive is adopted for filling, so that the purpose of sealing the chip without leakage is achieved, the MEMS chip and the ASIC chip are not damaged and the bonding part is not fallen under high pressure, the whole structure compactness is improved, in addition, the MEMS chip and the ASIC chip are only used as pressure sensing elements, the reliability and the stability of a product are improved, the cost and the manufacturable assembly cost of a pressure module are reduced, and large-scale automatic production is realized.

Optionally, on the basis of the above embodiment, side leads are formed on side walls of the circuit substrate, the first package circuit board, and the second package circuit board, the first pads and the second pads are in one-to-one correspondence, the first pads and the corresponding second pads are electrically connected through the side leads, and an interconnection line on the circuit substrate is electrically connected to the side leads.

Specifically, in this embodiment, there are various ways to provide the side leads on the side walls of the circuit substrate, the first package circuit board and the second package circuit board, for example, the leads may be directly soldered to the left and right sides of the circuit substrate, the first package circuit board or the second package circuit board by an electroplating process, or may be directly bonded to the left and right sides of the circuit substrate, the first package circuit board or the second package circuit board, as long as the signal transmission function is achieved, which is not limited herein.

Optionally, after the potting adhesive is filled inside the first package circuit board by using a dispensing process, the method further includes: and a plurality of leading-out electrodes are formed on the surface of the second packaging circuit board provided with a plurality of second bonding pads, the leading-out electrodes are electrically connected with the second bonding pads in a one-to-one correspondence mode, and the leading-out electrodes are used for outputting test signals.

When a plurality of extraction electrodes are provided on the surface of the second pad, the length of the extraction electrodes is not limited as long as the extraction electrodes are within a range that allows a customer to access the system under test

Optionally, forming a plurality of extraction electrodes on a surface of the second package circuit board provided with a plurality of second pads includes: and forming a plurality of extraction electrodes on the surface of the second packaging circuit board provided with the second bonding pads by adopting an electroplating process.

The process flow of forming the plurality of extraction electrodes on the surface of the second bonding pad can be simplified by using an electroplating process, and after the plurality of extraction electrodes are formed, a customer can access the system to be worked by using a bonding pad and the like as a second welding procedure, so that the working cycle of the whole pressure module is realized.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims

1. A pressure module, comprising:

2. The pressure module of claim 1, further comprising side leads, wherein the first pads are in one-to-one correspondence with the second pads, and the first pads are electrically connected with the corresponding second pads through the side leads;

3. The pressure module as claimed in claim 1, wherein a plurality of extraction electrodes are further disposed on the surface of the second package circuit board on which the second pads are disposed, the extraction electrodes being electrically connected to the second pads in a one-to-one correspondence, and the extraction electrodes being configured to output a test signal.

4. The pressure module of claim 1, wherein the substrate material of the circuit substrate and the first and second package circuit boards are ceramic or glass.

5. The pressure module of claim 1, wherein the second package circuit board is bonded to the first package circuit board by an epoxy adhesive, and the first package circuit board is bonded to the circuit substrate by an epoxy adhesive.

6. The pressure module of claim 1, wherein the potting adhesive is an epoxy, silicone, or polyurethane.