WO2021109303A1

WO2021109303A1 - Waterproof and dustproof pressure sensor and processing method therefor

Info

Publication number: WO2021109303A1
Application number: PCT/CN2019/130236
Authority: WO
Inventors: 李向光; 方华斌; 付博; 张硕
Original assignee: 潍坊歌尔微电子有限公司
Priority date: 2019-12-02
Filing date: 2019-12-31
Publication date: 2021-06-10
Also published as: CN110987280A

Abstract

Disclosed are a waterproof and dustproof pressure sensor and a processing method therefor. The waterproof and dustproof pressure sensor comprises an encapsulation structure formed by a housing and a substrate (2), a chip (3) is arranged in the encapsulation structure, and the chip (3) is fixed on the substrate (2) and is electrically connected to the substrate (2). The housing comprises a plastic encapsulation structure (11) and a chip sensitive area protective film (12), wherein the plastic encapsulation structure (11) is arranged around the chip (3), a sensitive area of the chip (3) is arranged outside the plastic encapsulation structure (11), and the bottom end of the plastic encapsulation structure (11) is fixed on the substrate (2); and the chip sensitive area protective film (12) is arranged at the upper end of the sensitive area of the chip (3), and end portions of the chip sensitive area protective film (12) are in sealed connection with the plastic encapsulation structure (11). The problems in the prior art, such as realizing a waterproof function by filling an encapsulation structure with silica gel, however as silica gel is easily contaminated with foreign matter, product performance is affected, can be solved.

Description

Waterproof and dustproof pressure sensor and processing method thereof

Technical field

The present invention relates to the technical field of pressure sensors, and more specifically, to a water- and dust-proof pressure sensor and a processing method thereof.

Background technique

The waterproof air pressure sensor is a device used to measure the ambient air pressure. The air pressure value is used to calculate the altitude, so it is widely used in consumer electronic terminals.

The current waterproof air pressure sensors are all realized by pouring silicone gel inside the product. Although it can achieve the waterproof function, the silica gel is easily contaminated with foreign objects and affects the product performance; and in order to reduce the process difficulty, the size of the product is relatively large.

Summary of the invention

In view of the above problems, one of the objectives of the present invention is to provide a waterproof and dustproof pressure sensor. The use of this waterproof and dustproof pressure sensor can solve the problem that the waterproof function is realized by filling silica gel inside the packaging structure in the prior art, but the silica gel is easily contaminated. Foreign matter, which can cause problems such as affecting product performance.

The present invention provides a water-proof and dust-proof pressure sensor, which includes a package structure formed by a housing and a substrate. A chip is arranged inside the package structure, and the chip is fixed on the substrate and is electrically connected to the substrate. The housing includes a plastic packaging structure and a chip sensitive area protective film; wherein the plastic packaging structure is arranged around the chip, and the sensitive area of the chip is arranged outside the plastic packaging structure, and the bottom end of the plastic packaging structure is fixed at On the substrate; the chip sensitive area protective film is arranged at the upper end of the sensitive area of the chip, and the end of the chip sensitive area protective film is hermetically connected with the plastic packaging structure.

In addition, a preferred solution is that a thermosetting connection layer is provided at the end of the protective film in the sensitive area of the chip; wherein the bottom end of the thermosetting connection layer is fixed on the chip; The top end is hermetically connected with the plastic sealing structure.

In addition, a preferred solution is that the chip is fixed in the middle of the substrate, the sensitive area of the chip is located in the middle of the top of the chip, and the plastic encapsulation structure is symmetrically arranged on the center perpendicular to the substrate. Around the chip.

In addition, a preferred solution is that the chip is fixed in the middle of the substrate by a patch glue.

In addition, a preferred solution is that the chip is electrically connected to the substrate through a metal wire, and the metal wire is arranged inside the plastic packaging structure.

In addition, a preferred solution is that the material of the plastic packaging structure is an epoxy plastic packaging compound.

In addition, a preferred solution is that the protective film for the sensitive area of the chip is a polytetrafluoroethylene film.

In addition, a preferred solution is that the bottom end of the plastic encapsulation structure is fixed on the substrate by an adhesive, wherein the adhesive is silver paste, solder paste, or epoxy glue.

In addition, a preferred solution is that the substrate is a BT resin substrate or a ceramic substrate.

Another object of the present invention is to provide a method for processing a water- and dust-proof pressure sensor as described above. The processing method includes the following steps:

S1. Fixing the chip on the substrate to obtain a first fixing structure of the chip and the substrate;

S2. Cover the sensitive area of the chip of the chip of the first fixing structure of the chip and the substrate with a protective film for the sensitive area of the chip to obtain a second fixing structure of the chip and the substrate;

S3, electrically connecting the chip and the substrate on the second fixing structure of the chip and the substrate to obtain a third fixing structure of the chip and the substrate;

S4. Perform injection molding processing around the chip on the third fixing structure of the chip and the substrate through an injection molding process, so that a plastic encapsulation structure is formed around the chip on the third fixing structure of the chip and the substrate, and the bottom of the plastic encapsulation structure is fixed On the substrate, the chip sensitive area protection film is located outside the plastic packaging structure, and the end of the chip sensitive area protection film is hermetically connected with the plastic packaging structure.

It can be seen from the above technical solutions that the housing of the waterproof and dustproof pressure sensor and its processing method provided by the present invention includes a plastic encapsulation structure and a chip sensitive area protective film. The chip sensitive area protective film can effectively protect the sensitive area of the chip and avoid foreign matter. In the sensitive area of the chip, the sensitivity of the chip is reduced, which affects the performance of the product. The plastic packaging structure can effectively protect the electrical connection between the chip and the substrate, ensuring that the product can achieve high reliability and high-level waterproof and dustproof effects.

In order to achieve the above and related objects, one or more aspects of the present invention include features that will be described in detail later. The following description and the drawings illustrate certain exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. Furthermore, the present invention is intended to include all these aspects and their equivalents.

Description of the drawings

By referring to the following description in conjunction with the accompanying drawings, and with a more comprehensive understanding of the present invention, other objectives and results of the present invention will be more clear and easy to understand. In the attached picture:

Fig. 1 is a schematic structural diagram of a waterproof and dustproof pressure sensor according to an embodiment of the present invention;

Fig. 2 is a schematic top view of the structure of a water- and dust-proof pressure sensor according to an embodiment of the present invention;

3 to 5 are schematic diagrams of the processing process of a waterproof and dustproof pressure sensor according to an embodiment of the present invention;

The reference signs include: 11-plastic packaging structure, 12-chip sensitive area protective film, 121-thermosetting connection layer, 2-substrate, 3-chip, 4-metal wire, 5-chip adhesive.

The same reference numerals in all the drawings indicate similar or corresponding features or functions.

Detailed ways

In the following description, for illustrative purposes, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is obvious that these embodiments can also be implemented without these specific details.

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 shows the structure of a waterproof and dustproof pressure sensor according to an embodiment of the present invention.

As shown in Fig. 1, a water-proof and dust-proof pressure sensor includes a package structure formed by a housing and a substrate 2. A chip 3 is arranged inside the package structure. The chip 3 is fixed on the substrate 2 and is electrically connected to the substrate 2. The housing includes a plastic packaging structure 11 and a chip sensitive area protection film 12; wherein the plastic packaging structure 11 is arranged around the chip 3, and the sensitive area of the chip 3 is arranged outside the plastic packaging structure 11, and the bottom end of the plastic packaging structure 11 is fixed on the substrate 2; The sensitive area protection film 12 is arranged on the upper end of the sensitive area of the chip 3, and the end of the chip sensitive area protection film 12 is hermetically connected with the plastic packaging structure 11.

Among them, the chip 3 can be a separate chip. For example, the chip 3 includes two separate ASIC chips and MEMS chips. The two chips can be arranged side by side, and the two chips are connected by metal wires, in the sensitive area of each chip. The upper end is provided with a chip sensitive area protective film 12; the above two chips can also be arranged in a stacked manner. For example, the ASIC chip is fixed on the substrate 2 first, and then the MEMS chip is fixed on the ASIC chip. Connect, set the chip sensitive area protective film 12 on the upper end of the sensitive area of the ASIC chip; of course, the chip 3 can also be an integrated single chip. In this case, it is only necessary to fix the integrated single chip on the substrate 2, and then the chip sensitive area protective film 12 is set at the upper end of the sensitive area of the integrated single chip.

As a preferred embodiment of the present invention, the chip 3 is fixed in the middle of the substrate 2, the sensitive area of the chip 3 is located in the middle of the top of the chip 3, and the plastic packaging structure 11 is symmetrically arranged around the chip 3 with the middle perpendicular of the substrate 2 as the center. Through the above structural design, the internal structure of the entire sensor is more regular, and it is more convenient to cooperate with the terminal device.

Wherein, the shape of the shell can be a rectangular parallelepiped or a cube, or a stepped cylinder (as shown in Figures 1 and 2). Here, the shape of the shell is not particularly limited.

As a preferred embodiment of the present invention, a thermosetting connection layer 121 is provided at the end of the protective film 12 in the sensitive area of the chip; the bottom end of the thermosetting connection layer 121 is fixed on the chip 3; the top end of the thermosetting connection layer 121 is connected to the plastic packaging structure 11 Seal the connection. By arranging the thermosetting connection layer 121 at the end of the chip sensitive area protective film 12, it is convenient to fix the chip sensitive area protective film 12 on the chip 3, and prevent the chip sensitive area protective film 12 from shifting during the use of the product. The chip sensitive area protective film 12 cannot protect the chip 3 and affects product performance.

Among them, preferably, the chip 3 is fixed to the middle of the substrate 2 by a patch adhesive 5.

Among them, preferably, the chip sensitive area protective film 12 is a polytetrafluoroethylene film (PTFE film for short), a thermosetting connection layer is provided at the end of the PTFE film, and the polytetrafluoroethylene film is used as a "non-stick coating" or "easy "Clean material" has the characteristics of resistance to acid, alkali, and various organic solvents, and it is almost insoluble in all solvents. At the same time, PTFE has the characteristics of high temperature resistance, its friction coefficient is extremely low, and will not affect the sensitivity of the chip 3.

As a preferred embodiment of the present invention, the chip 3 is electrically connected to the substrate 2 through a metal wire 4, and the metal wire 4 is arranged inside the plastic packaging structure 11. Metal wires are a common electrical connection method, but metal wires are easily corroded during the use of the product. Therefore, the metal wires are arranged inside the plastic packaging structure, and the plastic packaging structure protects the metal wires and prolongs the service life of the product.

Among them, preferably, the material of the plastic packaging structure 11 is an epoxy plastic packaging compound. Epoxy molding compound (EMC for short in English) is a powdery molding compound mixed with epoxy resin as matrix resin, high-performance phenolic resin as curing agent, silicon powder as filler, and various additives. The plastic packaging process uses transfer molding to extrude EMC into the mold cavity, embed the chips in it, and at the same time cross-link and solidify to form a semiconductor device with a certain structural appearance, which can achieve both waterproof and dust-proof effects. At the same time, it protects the metal wires.

Among them, preferably, the bottom end of the plastic encapsulation structure 11 is fixed on the substrate 2 by an adhesive, wherein the adhesive is silver paste, solder paste, or epoxy glue.

As a preferred embodiment of the present invention, the type of the substrate 2 is preferably a BT resin substrate or a ceramic substrate. Among them, BT resin is based on bismaleimide (BMI) and triazine as the main resin components, and epoxy resin, polyphenylene ether resin (PPE) or allyl compounds are added as modified components to form The thermosetting resin. Of course, the substrate may also be other types of substrates, such as epoxy resin substrates, etc., which are not particularly limited herein.

Figures 3 to 5 show the processing process of the waterproof and dustproof pressure sensor according to an embodiment of the present invention.

With reference to FIGS. 3 to 5, specific embodiments of the processing method of the waterproof and dustproof pressure sensor provided by the present invention will be described in detail.

The processing method of the waterproof and dustproof pressure sensor provided by the present invention includes the following steps:

As shown in Fig. 3, S1, the chip 3 is fixed on the substrate 2 to obtain a first fixing structure of the chip and the substrate.

Among them, the chip 3 may be a separate chip. For example, the chip 3 includes two separate ASIC chips and a MEMS chip. The two chips can be arranged side by side; they can also be arranged in a stacked manner; of course, the chip 3 can also be an integrated single chip. For the chip (as shown in FIG. 3), the preferred way for the chip 3 to be fixed on the substrate 2 is patch glue.

Preferably, the chip 3 is fixed on the middle part of the substrate 2 by patch glue; the sensitive area of the chip 3 is located in the middle part of the top end of the chip 3.

As shown in FIG. 4, S2, the chip sensitive area protective film 12 covers the sensitive area of the chip 3 of the first fixing structure of the chip and the substrate to obtain the second fixing structure of the chip and the substrate.

Among them, the chip sensitive area protective film 12 is a polytetrafluoroethylene film (PTFE film for short), and a thermosetting connection layer 121 is provided at the end of the chip sensitive area protection film 12; the bottom end of the thermosetting connection layer 121 is fixed to the chip 3 on.

As shown in FIG. 5, S3, the chip 3 and the substrate 2 on the second fixing structure of the chip and the substrate are electrically connected to obtain the third fixing structure of the chip and the substrate.

Wherein, the connection mode of the electrical connection between the chip 3 and the substrate 2 is electrical connection through a metal wire.

As shown in FIG. 1, S4, the chip 3 on the third fixing structure of the chip and the substrate is injection molded through an injection process, so that a plastic packaging structure 11 is formed around the chip 3 on the third fixing structure of the chip and the substrate. The bottom of the chip 11 is fixed on the substrate 2, the chip sensitive area protection film 12 is located outside the plastic packaging structure 11, and the end of the chip sensitive area protection film 12 is hermetically connected to the plastic packaging structure 11.

Specifically, the top end of the thermosetting connection layer 121 at the end of the chip sensitive area protective film 12 is connected to the plastic packaging structure 11, and the material of the injection molding structure 11 is epoxy plastic packaging material. Through the injection molding process, the shape of the plastic-encapsulated product can be a rectangular parallelepiped or a cube to achieve a single waterproof and dustproof; it can also be a stepped cylinder. This form can be fitted with an O-ring to cooperate with the terminal structure for overall waterproof and dustproof.

The working principle of the waterproof and dustproof pressure sensor shown in FIG. 1 provided by the present invention is:

The sensitive area of the chip 3 receives the external pressure change signal, converts the pressure change signal to form a digital signal, and then transmits the digital signal to the substrate 2 through a metal wire. The substrate 2 is provided with pads, and the pads are electrically connected to external devices. Connect, and transmit the signal through the pad.

The chip sensitive area protective film 12 can effectively protect the sensitive area of the chip 3 by arranging the chip sensitive area protection film 12 on the sensitive area of the chip 3 to prevent foreign matter from adhering to the sensitive area of the chip, which will reduce the sensitivity of the chip and affect the product performance. The plastic packaging structure 11 can effectively The electrical connection between the chip 3 and the substrate 2 is protected to ensure that the product can achieve high-reliability, high-level waterproof and dust-proof effects.

As above, the waterproof and dustproof pressure sensor and the processing method thereof according to the present invention are described by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various improvements can be made to the waterproof and dustproof pressure sensor and its processing method proposed by the present invention without departing from the content of the present invention. Therefore, the protection scope of the present invention should be determined by the content of the appended claims.

Claims

A water-proof and dust-proof pressure sensor includes a packaging structure formed by a casing and a substrate. A chip is arranged inside the packaging structure, and the chip is fixed on the substrate and electrically connected to the substrate, and is characterized in ,

The housing includes a plastic packaging structure and a protective film for the sensitive area of the chip; wherein,

The plastic package structure is arranged around the chip, and the sensitive area of the chip is arranged outside the plastic package structure, and the bottom end of the plastic package structure is fixed on the substrate;

The chip sensitive area protective film is arranged on the upper end of the sensitive area of the chip, and the end of the chip sensitive area protective film is hermetically connected with the plastic packaging structure.
The waterproof and dustproof pressure sensor according to claim 1, wherein:

A thermosetting connection layer is provided at the end of the protective film in the sensitive area of the chip; wherein,

The bottom end of the thermosetting connection layer is fixed on the chip;

The top end of the thermosetting connecting layer is in hermetically connected with the plastic sealing structure.
The waterproof and dustproof pressure sensor according to claim 1, wherein:

The chip is fixed in the middle of the substrate, the sensitive area of the chip is located in the middle of the top of the chip, and the plastic packaging structure is symmetrically arranged around the chip with the center perpendicular of the substrate as the center.
The waterproof and dustproof pressure sensor according to claim 3, wherein:

The chip is fixed on the middle of the substrate by a patch glue.
The waterproof and dustproof pressure sensor according to claim 1, wherein:

The chip is electrically connected to the substrate through a metal wire, and the metal wire is arranged inside the plastic packaging structure.
The waterproof and dustproof pressure sensor according to claim 1, wherein:

The material of the plastic packaging structure is epoxy plastic packaging material.
The waterproof and dustproof pressure sensor according to claim 1, wherein:

The protective film for the sensitive area of the chip is a polytetrafluoroethylene film.
The waterproof and dustproof pressure sensor according to claim 1, wherein:

The bottom end of the plastic encapsulation structure is fixed on the substrate by an adhesive, wherein the adhesive is silver paste or solder paste or epoxy glue.
The waterproof and dustproof pressure sensor according to claim 1, wherein:

The substrate is a BT resin substrate or a ceramic substrate.
A method for processing a waterproof and dustproof pressure sensor according to any one of claims 1 to 9, characterized in that it comprises the following steps:

S1. Fixing the chip on the substrate to obtain a first fixing structure of the chip and the substrate;

S2. Cover the sensitive area of the chip of the chip of the first fixing structure of the chip and the substrate with a protective film for the sensitive area of the chip to obtain a second fixing structure of the chip and the substrate;

S3, electrically connecting the chip and the substrate on the second fixing structure of the chip and the substrate to obtain a third fixing structure of the chip and the substrate;

S4. Perform injection molding processing around the chip on the third fixing structure of the chip and the substrate through an injection molding process, so that a plastic encapsulation structure is formed around the chip on the third fixing structure of the chip and the substrate, and the bottom of the plastic encapsulation structure is fixed On the substrate, the chip sensitive area protection film is located outside the plastic packaging structure, and the end of the chip sensitive area protection film is hermetically connected with the plastic packaging structure.