CN112014026A

CN112014026A - Pressure sensor and manufacturing method thereof

Info

Publication number: CN112014026A
Application number: CN201910450740.8A
Authority: CN
Inventors: 宁世朝; 蔡芳松; 程勇
Original assignee: Hefei Jiefa Technology Co ltd
Current assignee: Wuhan Jiekai Technology Co ltd
Priority date: 2019-05-28
Filing date: 2019-05-28
Publication date: 2020-12-01
Anticipated expiration: 2039-05-28
Also published as: CN112014026B

Abstract

The application discloses a pressure sensor and a manufacturing method thereof. Wherein, this pressure sensor includes: a substrate; a pressure sensing device disposed on one side of the substrate; the packaging shell covers the one side of the substrate, a cavity is arranged on the packaging shell, the cavity is arranged on the pressure sensing device, and at least part of a sensing area in the upper surface of the pressure sensing device is exposed out of the bottom of the cavity; the upper surface of the pressure sensing device is provided with an isolation structure, and the isolation structure is used for isolating an external object from acting on the sensing area. According to the scheme, the manufacturing yield of the pressure sensor can be improved.

Description

Pressure sensor and manufacturing method thereof

Technical Field

The application relates to the technical field of sensing, in particular to a pressure sensor and a manufacturing method thereof.

Background

Pressure sensors are widely used in consumer electronics, automotive electronics, and industrial electronics. For example, in the automotive electronics industry, the application of a tire pressure monitoring system can monitor the condition of tire pressure, and thus, the occurrence of traffic accidents is greatly reduced.

Since the pressure sensing device of the pressure sensor needs to sense the external pressure, the packaging requirement of the pressure sensing device of the pressure sensor is different from the packaging requirement of the control device of the pressure sensor. Based on the special packaging requirements of the pressure sensor, how to improve the manufacturing yield of the pressure sensor is a key issue at present.

Disclosure of Invention

The technical problem that this application mainly solved is to provide pressure sensor and preparation method, can improve pressure sensor's preparation yield.

In order to solve the above problem, a first aspect of the present application provides a pressure sensor including:

a substrate;

a pressure sensing device disposed on one side of the substrate;

a package housing covering the one side of the substrate, the package housing having a cavity disposed thereon, the cavity being disposed on the pressure sensing device, and at least a portion of a sensing area in an upper surface of the pressure sensing device being exposed at a bottom of the cavity;

the upper surface of the pressure sensing device is provided with an isolation structure, and the isolation structure is used for isolating an external object from acting on the sensing area.

In order to solve the above problem, a second aspect of the present application provides a method for manufacturing a pressure sensor, including:

providing a substrate;

providing a pressure sensing device on one side of a substrate; the upper surface of the pressure sensing device is provided with an isolation structure, and the isolation structure is used for isolating a sensing area acted on by an external object in the upper surface of the pressure sensing device;

and injecting a packaging material into one side of the substrate, and opening the packaging material through a mold corresponding to the isolation structure through a protective film to form a packaging shell provided with a cavity, wherein the cavity is arranged on the pressure sensing device, and at least part of a sensing area in the upper surface of the pressure sensing device is exposed at the bottom of the cavity.

In the above scheme, the pressure sensor can be provided with the cavity of the packaging shell on the pressure sensing device, and at least the packaging shell is utilized to package each device of the multi-device packaging structure, and the cavity is utilized to expose the sensing area of the pressure sensing device so as to sense pressure, wherein the upper surface of the pressure sensing device is provided with the isolation structure to prevent an external object from acting on the sensing area, so that the pressure sensing device can be effectively protected, the effective sensing of pressure is ensured, and the reliability of pressure sensing is improved.

Drawings

FIG. 1 is a schematic side sectional view of a first embodiment of a pressure sensor of the present application;

FIG. 2 is a schematic side cross-sectional view of a first embodiment of a pressure sensing device of the pressure sensor of the present application;

FIG. 3 is a schematic side sectional view of a second embodiment of the pressure sensor of the present application;

FIG. 4 is a schematic side cross-sectional view of a third embodiment of the pressure sensor of the present application;

FIG. 5 is a schematic side cross-sectional view of a fourth embodiment of the pressure sensor of the present application;

FIG. 6 is a schematic side sectional view of a fifth embodiment of the pressure sensor of the present application;

FIG. 7 is a schematic side cross-sectional view of a sixth embodiment of a pressure sensor of the present application;

FIG. 8 is a schematic side cross-sectional view of a seventh embodiment of a pressure sensor of the present application;

FIG. 9 is a schematic side cross-sectional view of an eighth embodiment of a pressure sensor of the present application;

FIG. 10 is a schematic side sectional view of a ninth embodiment of the pressure sensor of the present application;

FIG. 11 is a schematic side sectional view of a tenth embodiment of the pressure sensor of the present application;

FIG. 12 is a schematic side cross-sectional view of a second embodiment of a pressure sensing device of the pressure sensor of the present application;

FIG. 13 is a schematic side cross-sectional view of a third embodiment of a pressure sensing device of the pressure sensor of the present application;

FIG. 14 is a schematic side cross-sectional view of a fourth embodiment of a pressure sensing device of the pressure sensor of the present application;

FIG. 15 is a schematic side cross-sectional view of a fifth embodiment of a pressure sensing device of the pressure sensor of the present application;

FIG. 16 is a schematic side cross-sectional view of a sixth embodiment of a pressure sensing device of the pressure sensor of the present application;

FIG. 17 is a schematic side cross-sectional view of a seventh embodiment of a pressure sensing device of the pressure sensor of the present application;

FIG. 18 is a schematic flow chart diagram illustrating one embodiment of a method of making a pressure sensor according to the present application;

FIGS. 19a to 19h are schematic structural diagrams of a pressure sensor manufactured by steps corresponding to an embodiment of a method for manufacturing a pressure sensor according to the present application;

fig. 20 is a schematic flow chart illustrating a method of manufacturing a pressure sensor according to another embodiment of the present disclosure.

Detailed Description

The following describes in detail the embodiments of the present application with reference to the drawings attached hereto.

In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular system structures, interfaces, techniques, etc. in order to provide a thorough understanding of the present application.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship. A plurality or a plurality of the applications mentioned in the present application is to be understood as two or more.

The pressure sensors described herein may be used in any pressure sensing system, such as may be used in a tire pressure monitoring system (tire pressure monitoring system). In particular, the pressure sensor may be a tire pressure monitoring chip.

Referring to fig. 1, fig. 1 is a schematic side sectional view of a pressure sensor according to an embodiment of the present disclosure. In this embodiment, the pressure sensor 100 includes a substrate 110, a control device 120, a pressure sensing device 130, a package housing 140, and a protective layer 150.

Specifically, the substrate 110 may be, but is not limited to, a metal lead frame, a plastic substrate, a ceramic substrate, or the like.

The control device 120 is arranged at one side 111 of the substrate 110. In one embodiment, the control device 120 may be fixed on the substrate 110 by a first device adhesive material 121 and may be electrically connected to the substrate 110 by a bonding wire 122. The control device 120 may be a Micro Controller Unit (MCU) chip.

The pressure sensing device 130 is disposed on one side 111 of the substrate 110. The pressure sensing device 130 may be fixed to the side 111 of the substrate 110 by a second device adhesive material 131, and may be electrically connected to the substrate 110 or the control device 120 by a bonding wire 132. For example, as shown in fig. 1, the pressure sensing device 130 is fixed on the upper surface 123 (it is understood that the upper surface described herein is the surface of the corresponding device or structure away from the substrate) of the control device 120, and the pressure sensing device 130 is electrically connected to the control device 120 through a bonding wire 132; for another example, as shown in fig. 7, the pressure sensing device 130 and the control device 120 are respectively fixed on the surface of one side 111 of the substrate 110, and the pressure sensing device 130 is electrically connected to the substrate 110 by a bonding wire 132.

The pressure sensing device 130 is provided with a sensing area for sensing an external pressure. Specifically, referring to fig. 2 in conjunction, the pressure sensing device 130 includes a sensing region 133 and an outer pressure sensing enclosed cavity 134, the sensing region 133 corresponding to a surface of the outer pressure sensing enclosed cavity 134 (it is understood that the surface of the sensing enclosed cavity described herein can be any orientation of the surface within the sensing enclosed cavity). Specifically, the sensing region 133 is formed by a first pressure membrane 135, and one surfaces of the sensing region 133 and the outer pressure-sensing closed cavity 134 are opposite sides of the first pressure membrane 135, respectively.

The package body 140 is disposed on the side 111 of the substrate 110, and has a cavity 141, and at least a portion of the sensing region 133 of the pressure sensing device 130 is exposed at a bottom 1411 of the cavity 141. In a specific application, the package housing 140 may be any material capable of protecting a device, and is typically a relatively rigid material such as plastic.

Specifically, as shown in fig. 1, the package body 140 may cover devices on the side 111 of the substrate 110 (which may be understood as covering part or all of the devices on the side 111 of the substrate 110), such as the control device 120, the sensing device 170 described below, bonding wires thereof, and the like, so as to package and protect devices other than the pressure sensing device 130, for example, the cavity 141 is disposed on the control device 120, and the bottom 1411 of the cavity 141 exposes at least a part of the upper surface of the control device 120, and the pressure sensing device 130 is disposed on the upper surface of the control device 120 at the bottom 1411 of the cavity. Of course, as shown in fig. 7, the cavity 141 is disposed on the substrate 110, and the bottom 1411 of the cavity 141 exposes a portion of the upper surface of the substrate 110, and the pressure sensing device 130 is disposed on the upper surface of the substrate 110 at the bottom 1411 of the cavity; alternatively, as shown in fig. 9, the package housing 140 may also partially cover the pressure sensing device 130, for example, the cavity 141 is disposed on the upper surface of the pressure sensing device 130, as long as it is ensured that a part of the sensing region 133 is exposed to the bottom 1411 of the cavity 141. For at least part of devices on the substrate 100 covered by the package casing 140, the cavity 141 is then packaged and protected by the following protection layer to protect the pressure sensing device 130, compared with the method of directly packaging all devices on the substrate by using the protection layer, the use of the protection layer material can be reduced, and the packaging cost of the protection layer is reduced. It should be noted that, in the embodiment shown in fig. 9, the cavity 141 is provided on the pressure sensing device 130, and a protection layer described below may be provided or disposed in the cavity according to actual requirements, that is, the pressure sensor may or may not include the protection layer described below. For example, if the bonding wires of the pressure sensing device 130 are not exposed in the cavity, the protection layer may not be disposed in the cavity, which further reduces the packaging cost and improves the sensitivity of the sensing region of the pressure sensing device to pressure.

It is understood that the package body 140 may not cover all or part of the devices on the substrate 110, for example, the package body 140 is disposed on the periphery of the side 111 of the substrate 110 to surround all the devices on the substrate 110, and all the devices are exposed at the bottom 1411 of the cavity 141. At this time, all devices on the substrate are covered with a protective layer described below for encapsulation protection.

The protective layer 150 is used to cover the devices in the cavity 141. As shown in fig. 1, the protection layer 150 covers the pressure sensing device 130 and the bonding wires 132 thereof. It is understood that if other devices are located in the cavity 141, the protective layer 150 covers the other devices and their associated bonding wires. In particular, the protective layer 150 may be a gel (gel) or other material having a certain elasticity to be able to transmit an external pressure to the pressure sensing device 130. For example, during the process of packaging the pressure sensor 100, glue is injected into the cavity 141 to a certain height to cover the devices in the cavity 141, and then the glue is cured to form gel, thereby protecting the devices in the cavity 141. The external pressure of the pressure sensor of the present embodiment is transmitted to the sensing region of the pressure sensing device 130 through the protective layer 150, so that the measurement of the external pressure can be realized.

With continued reference to fig. 1, the pressure sensor 100 may also be used to detect data other than pressure, and thus the pressure sensor 100 may further include at least one sensing device 160 for detecting other data, the at least one sensing device 160 being disposed on the side 111 of the substrate 110. As shown in fig. 1, the entirety of each sensing device 160 is covered by the package housing 140. It should be understood that in other embodiments, the sensing device 160 may also be partially covered by the package body 140 (e.g., the package body 140 only covers the bonding sites and the bonding wires of the sensing device 160), and the portion of the sensing device 160 not covered by the package body 140 may be covered by a protective layer or other material or directly exposed. Specifically, the sensing device 160 may be an acceleration, temperature, or the like sensing device. In a specific application, the pressure sensor 100 includes an acceleration sensing device 160 in addition to the above structure as a tire pressure monitoring chip capable of monitoring tire pressure and acceleration.

The at least one sensor device 160 may be integrated in one device group, in particular in a stacked or tiled manner. Additionally, as shown in FIG. 1, the at least one sensing device 160 can be disposed on the substrate 110. In another embodiment, as shown in fig. 8, the at least one sensing device 160 may be disposed on an upper surface of the control device 120. In one embodiment, the sensing device 160 may be fixed on the substrate 110 or the control device 120 by a third device adhesive material 161, and may be electrically connected to the substrate 110 or the control device 120 by a bonding wire 162. It is understood that the pressure sensor 100 may be provided with the sensing device 160 according to actual requirements, and in some embodiments, the pressure sensor 100 may not be provided with the sensing device 160, and thus is not limited thereto.

It is understood that the first device bonding material, the second device bonding material, and the third device bonding material may be the same or different bonding materials, and specifically may be conductive glue, non-conductive glue, adhesive film, underfill, molding compound, and the like. The control device, the pressure sensing device and the sensing device can be specifically a control chip, a pressure sensing chip and a related sensing chip. The control device, the pressure sensing device, the sensing device and the like can be arranged on a substrate or other devices in a flip-chip bonding mode.

With continued reference to fig. 1, in some embodiments, at least one corner of the sidewall 1412 of the cavity 141 of the package housing 140 may be provided with a chamfered structure. As shown in fig. 1, all corners of the sidewall 1412 of the cavity 141 may be chamfered. For the manufacturing process of the pressure sensor, the cavity 141 is usually formed by pressing the encapsulant with a mold, and the shape of the sidewall 1412 of the cavity 141 depends on the shape of the mold. In order to protect the device or the substrate in the corresponding cavity 141, the mold is usually used to press the encapsulant through the protection film, so as to reduce the pressure of the mold on the device or the substrate in the formed cavity. In order to avoid damage to the protective film easily caused when the mold presses the packaging material through the protective film, at least part of corners of the mold can be set to be chamfered, and then the corresponding corner of the cavity 141 is finally formed to be chamfered. Therefore, the stress concentration of the protective film in the cavity opening process is reduced, the protective film is prevented from being damaged, the service life of the protective film in the manufacturing process is prolonged, the alarm rate caused by the damage of the protective film in the manufacturing process is reduced, and the manufacturing yield (also called packaging yield) is improved.

With continued reference to fig. 1, in some embodiments, the sidewall 1412 of the cavity 141 may be configured as a stepped structure. For example, the sidewall 1412 includes a plurality of steps 1412a, and the steps 1412a are sequentially connected to form a stepped structure. At least one corner of the stepped structure is a chamfered structure, for example, the end corner 1412a1 of each step 1412a and the connection 1412b between the steps 1412a are chamfered structures. In addition, the step 1412a may be configured in any shape according to actual requirements, for example, the step 1412a shown in fig. 1 is rectangular or rectangular-like, and the upper surface of the step 1412a may be horizontal (shown in fig. 1) or have a certain angle with the horizontal plane. In addition, the included angle β formed by the connection 1412b between the steps 1412a can be set to be a right angle (as shown in fig. 1), an obtuse angle (as shown in fig. 3) or an acute angle (as shown in fig. 4) according to actual requirements. In this embodiment, the sidewall of the cavity 141 is set to be stepped, so that the depth of each step of the sidewall is reduced compared with the depth of the whole non-stepped sidewall (as shown in fig. 5), and thus the stress concentration of the protective film in the packaging process is also reduced, the protective film is prevented from being damaged, the service life of the protective film in the manufacturing process is prolonged, the alarm rate caused by the damage of the protective film in the manufacturing process is reduced, and the manufacturing yield is improved.

It is understood that in the embodiment where the sidewall is stepped, the height of a certain step 1412a can be used as the reference height of the protection layer 150, i.e., the height of the protection layer is added to the height of a certain step 1412a when the protection layer 150 is added. Further, as shown in fig. 4, the connection 1412b between the steps 1412a may be a groove extending toward the substrate 110, so that when the protective layer is added, the height of a certain step 1412a may be used as a reference height of the protective layer, and the protective layer material thermally converted into liquid is added into the cavity 141 to the height of a certain step 1412a and then stops being added, and the excess protective layer material may flow into the groove of the connection 1412 b.

In addition, the sidewall 1412 of the cavity 141 may not have a stepped structure, and as shown in fig. 5, the sidewall 1412 corresponds to a step having a large depth. Wherein, the corner 1412c of the sidewall 1412 can be, but is not limited to be, provided with a chamfered structure.

With continued reference to fig. 1, in some embodiments, to further improve the protection of the devices in the cavity 141, the pressure sensor 100 may further include a cover 170. The cover 170 covers the cavity 141, and an opening 172 is disposed at a position corresponding to the cavity 141. The cover 170 is used to further protect the devices in the cavity 141. The pressure sensor of the present embodiment varies the air pressure in the cavity through the opening, and the pressure sensing device 130 measures the external pressure by sensing the air pressure in the cavity 141. Of course, in other embodiments, the cover 170 may not be provided on the pressure sensor 100, and is not limited herein.

Specifically, the cover 170 is connected to at least a portion of the upper surface 142 of the package housing 140 and extends above the cavity 141 through the connecting portion, so as to cover the cavity 141. Specifically, the cover 170 may achieve the connection through the cover adhesive material 171. Since the upper surface 142 of the package housing 140 has a larger area, the cover 170 can be bonded with a larger area to improve the reliability of the cover connection, and the process is simple, the warpage of the package housing is smaller, and the heat dissipation capability is stronger. It is understood that, in order to achieve the maximum connection reliability, the upper surface of the package housing 140 may be used as a connection area to the cover 170, i.e., cover the cover bonding material 171 and the connection cover 170. However, in the case that the area of the upper surface 142 of the package housing 140 is larger, the cover 170 may be selectively connected to a portion of the upper surface 142 of the package housing 140, wherein the height of at least a portion of the upper surface 1422 that is not connected to the cover 170 is equal to or lower than the height of the upper surface 1421 that is connected to the cover 170. For example, as shown in fig. 1, the height of the upper surface 1422 of the package housing 140 not connected to the cover 170 is equal to the height of the upper surface 1421 connected to the cover 170; alternatively, as shown in fig. 6, the height h1 of the upper surface 1422 of the package case 140, which is not connected to the cover 170, is lower than the height h2 of the upper surface 1421 connected to the cover 170, so as to reduce the usage of the package material and reduce the cost.

It is understood that in the case that the cover 170 is attached to at least a portion of the upper surface of the package housing 140, the cover 170 may be disposed to cover the entire upper surface of the package housing 140, as shown in fig. 1, and the cover 170 covers the upper surface of the package housing 140 that is not attached to the cover 170. By covering the entire upper surface of the package case 140 with the cover, warpage of the package case can be made smaller

In addition, in the embodiment where the sidewall 1412 is stepped, the cover 170 may be connected to a step of the sidewall 1412, for example, by a cover adhesive material, so that the area of the cover 170 may be reduced and the cost may be reduced. In addition, the cover bonding material can be realized by a device bonding material, such as glue, double-sided tape, etc.

Referring to fig. 7 and 8, the pressure sensing device 130 of the pressure sensor 100 may be disposed on the surface of one side 111 of the substrate 110. Specifically, the cavity 141 of the package housing 140 is disposed on the substrate 110, a bottom 1411 of the cavity 141 exposes a portion of the surface of the substrate 110, the pressure sensing device 130 is disposed on the surface of the substrate 110 at the bottom 1411 of the cavity, and the protection layer 150 covers the pressure sensing device 130 and the bonding wires 132 thereof. Wherein for the embodiment shown in fig. 8, the sensing device 170 may be disposed on the upper surface of the control device 120.

Referring to fig. 9 to 11, the cavity 141 of the pressure sensor 100 is disposed on the pressure sensing device 130, and a part of the sensing region of the pressure sensing device 130 is exposed at the bottom 1411 of the cavity 141. In some embodiments, as shown in fig. 9, the pressure sensing device 130 may be disposed on an upper surface of the control device 120, and the sensing device 160 may be disposed on the substrate 110, but the sensing device 160 and the pressure sensing device 130 may also be disposed on the control device 120 separately, which is not limited herein. In some embodiments, as shown in fig. 10, the pressure sensing device 130 may also be disposed on the substrate 110 separately from the control device 120. In some embodiments, as shown in fig. 11, the pressure sensing device 130 may be disposed on the substrate 110 separately from the control device 120, and the sensing device 160 may be disposed on an upper surface of the control device 120. For the embodiment in which the cavity 141 of the pressure sensor 100 is disposed on the pressure sensing device 130, a protective layer may be disposed or not disposed in the cavity 141 according to actual requirements.

In the above embodiment, the cavity sidewall 1412 of the pressure sensor may or may not be provided with the above-mentioned chamfered structure and stepped structure as required, and the control device 120, the sensing device 160 and the cover 170 may also be selectively provided according to the actual requirement of the pressure sensor, which is not limited herein. For example, in one embodiment, the pressure sensing device may be packaged separately to obtain a pressure sensor, and other devices such as the control device and the sensing device may be separately packaged into another control system, in which case the pressure sensor may not be provided with the control device and the sensing device. However, compared with the case of separately packaging the control device, the above embodiment packages the pressure sensing device together with the control device, the sensing device, and other devices, so as to obtain a smaller system in package (system in package), and reduce the package size, so that the control device and the pressure sensing device can be directly interconnected at a packaging level, and the package parasitic between the devices is reduced.

For the above embodiments, in order to prevent the sensing region of the pressure sensing device 130 from being damaged by an external object, please refer to fig. 12-14, the upper surface 136 of the pressure sensing device 130 is further provided with an isolation structure 137, and the isolation structure 137 is used to isolate the sensing region 133 of the upper surface 136 from the external object. For example, for the embodiment in which the cavity of the package housing is disposed on the pressure sensing device, during the manufacturing process, the mold needs to be used to act on the package material through the protective film to form the cavity on the pressure sensing device, and at this time, the isolation structure 137 may be used to prevent the mold from acting on the sensing region to damage the sensing region.

In some embodiments, as shown in FIG. 12, isolation structure 137 includes a protective cavity 1371 formed by upper surface 136 extending toward a lower surface of pressure sensing device 130, wherein an upper surface portion, which is a bottom or sidewall of protective cavity 137, is a sensing region 133 of the pressure sensing device. For example, for the embodiment in which the external pressure sensing closed cavity 134 is disposed at the bottom of the protection cavity 137, the upper surface portion of the bottom of the protection cavity 137 is one side of the first pressure membrane 135, and a portion of the surface of the external pressure sensing closed cavity 134 is the other side of the first pressure membrane 135; for the embodiment in which the closed external pressure sensing chamber 134 is disposed at the side of the protection chamber 137, the upper surface of the sidewall of the protection chamber 137 is a portion of one side of the first pressure membrane 135, and a portion of the surface of the closed external pressure sensing chamber 134 is the other side of the first pressure membrane 135

In some embodiments, as shown in fig. 13, the isolation structure 137 includes a protection cover 1372 disposed on the upper surface 136, the protection cover 1372 and the sensing region 133 in the upper surface 136 form a space 13721, and the protection cover 1372 is provided with an opening 13722 communicating with the space 13721. Specifically, the upper surface of the pressure sensing device 130 is provided with a first pressure membrane 135, wherein one side of the first pressure membrane 135 is used as the sensing region 133 in the upper surface 136, and the other side of the first pressure membrane 135 is part of the surface of the external pressure sensing closed cavity 134.

In some embodiments, as shown in fig. 14, the isolation structure 137 may include the protection cavity 1371 and the protection cover 1372.

In the embodiment with the isolation structure, the protection cavity 1371 and/or the protection cover 1372 in the isolation structure can prevent the damage of the mold to the first pressure film 135 when the mold is used to open the cavity on the pressure sensing device in the process of manufacturing the pressure sensor, so that the first pressure film 135 can be protected.

Referring to fig. 15-17, in particular, fig. 15 shows an embodiment in which the isolation structure includes the protection cavity 1371, fig. 16 shows an embodiment in which the isolation structure includes the protection cover 1372, and fig. 17 shows an embodiment in which the isolation structure includes the protection cavity 1371 and the protection cover 1372. To improve the accuracy of the pressure measurement of the pressure sensing device 130, the pressure sensing device 130 may be provided with a reference pressure sensing closed cavity 138 and a second pressure membrane 139 in addition to the outer pressure sensing closed cavity 134 and the first pressure membrane 135. Wherein, the two opposite sides of the second pressure film 139 are respectively the other surface of the external pressure sensing closed cavity 134 and one surface of the reference pressure sensing closed cavity 138. The reference pressure sensing enclosed cavity 138 may be vacuum disposed. In performing the pressure measurement, the current sensing values of the external pressure sensing closed cavity 134 and the reference pressure sensing closed cavity 138 can be measured by using the first pressure film 135 and the second pressure film 139, respectively; the current sensed value of the external pressure sensing enclosed cavity 134 is compensated based on the current sensed value of the reference pressure sensing enclosed cavity 138 and the reference sensed value of the reference pressure sensing enclosed cavity 138 measured before encapsulation to obtain an accurate measured pressure value. The compensation structure can ensure accurate measurement of pressure data when the package shell 130 is warped and the like.

It will be appreciated that the pressure sensing device 130 may optionally be provided with the above-mentioned isolation structure and the reference pressure sensing closed cavity according to actual requirements, for example, in an embodiment, the pressure sensing device 130 may not be provided with the isolation structure, and only the reference pressure sensing closed cavity is provided. Therefore, the specific structure of the pressure sensing device is not limited herein. Referring to fig. 18, fig. 18 is a schematic flow chart illustrating a manufacturing method of a pressure sensor according to an embodiment of the present disclosure. In this embodiment, the manufacturing method includes the following steps:

s1810: a substrate is provided.

As shown in fig. 19a, a substrate 1910 is provided. The substrate 1910 may be, but is not limited to, a metal lead frame, a plastic substrate, a ceramic substrate, or the like.

S1820: a control device is provided on one side of the substrate.

As shown in fig. 19b, a control device 1920 is disposed on one side of the substrate 1910, wherein the control device 1920 can be bonded to the substrate 1910 with a first device bonding material 1921.

It is understood that for pressure sensors that also sense data other than pressure, this step further includes providing at least one sensing device 1960 on one side of the substrate 1910, wherein the sensing device 1960 can be bonded to the substrate 1910 with a third device bonding material 1961. Of course, in other embodiments, this step may also include disposing at least one sensing device 1960 on the control device 1920 such that the sensing device 1960 is stacked on the control device 1920.

With continued reference to fig. 19c, after the associated devices are placed, the present step may further include connecting the associated devices with wire bonds. For example, control device 1920 is connected to substrate 1910 by wire bonds 1922, and sensor device 1960 is connected to control device 1920 by wire bonds 1962.

S1830: and injecting a packaging material into one side of the substrate, and opening the packaging material through a protective film by using a mold to form a packaging shell with a cavity.

As shown in fig. 19d, an encapsulating housing 1940 provided with a cavity 1941 is formed as shown in fig. 19e by injecting an encapsulating material 1940 on one side of a substrate 1910 and pressing the encapsulating material 1940 through a protective film 1949 with a mold 1948 to perform an open cavity (open cavity). The packaging material can be plastic, so that the cavity can be formed by adopting a mode of molding an open cavity.

It is understood that the present embodiment uses a mold 1948 that opens corresponding to the position of the control device 1920 to form a cavity 1941 that exposes at least a portion of the upper surface of the control device 1920. In other embodiments, the mold 1948 can be used to open the cavity corresponding to the substrate to form a cavity 1941 that exposes at least a portion of the upper surface of the substrate 1910.

In some embodiments, at least one corner of the sidewall of the cavity 1941 is chamfered. Specifically, the encapsulant 1940 is opened through the protective film 1949 using a mold 1948 having at least one chamfered corner, to form cavities 1941 having respective chamfered corners. Therefore, stress concentration of the protective film can be reduced due to the chamfer, and the protective film is prevented from being damaged, so that the manufacturing yield is improved.

In some embodiments, the sidewall of the cavity 1941 can be provided as a stepped structure. Specifically, the encapsulating material 1940 is step-opened (step open cavity) through the protective film 1949 using the molds 1948 whose respective side walls are step-shaped structures to form the cavity 1941 whose side walls are step-shaped structures. Therefore, the depth of each step is lower than the depth of the whole side wall due to the stepped structure, so that the stress concentration of the protective film can be reduced, the protective film is prevented from being damaged, the process control in the cavity opening process is facilitated, and the manufacturing yield is improved. In addition, the step of the step-shaped structure can also be used as a height reference surface for adding the protective layer.

In some embodiments, the package housing 1940 is formed to cover devices on one side of the substrate 1910 such as the control device 1920 and the sensing device 1960, etc., and the cavity 1941 is disposed on the control device 1920 or the substrate 1910 and the bottom of the cavity 1941 is exposed to a portion of the surface of the control device 1920 or a portion of the surface of the substrate 1910.

S1840: a pressure sensing device is disposed within the cavity.

As shown in fig. 19f, a pressure sensing means 1930 is provided on the control means 1920 at the bottom of the cavity 1941, wherein the pressure sensing means 1930 may be pressed against the control means 1920 using a second means adhesive material 1931. Of course, in other embodiments where the bottom of the cavity 1941 exposes the substrate 1910, the pressure sensing device 1930 may be disposed on the substrate 1910 at the bottom of the cavity 1941.

With continued reference to fig. 19g, after disposing the pressure sensing device 1930, the present step may further include connecting the pressure sensing device 1930 with a wire bond. For example, pressure sensing device 1930 is connected to control device 1920 using wire bond 1932. Of course, in other embodiments where the bottom of the cavity 1941 is exposed to the substrate 1910, the pressure sensing devices 1930 may be coupled to the substrate 1910 using wire bonds 1932 after the pressure sensing devices 1930 are disposed on the substrate 1910 at the bottom of the cavity 1941.

S1850: and covering the device in the cavity with a protective layer.

As shown in fig. 19h, a protective layer 1950, such as a gel, is injected within cavity 1941 to cover pressure sensing device 1930 and its bonding wires within cavity 1941. It will be appreciated that to be able to protect pressure sensing device 1930 and its bonding wires within cavity 1941, the height of the protective layer should be higher than the height of pressure sensing device 1930 and its bonding wires.

In some embodiments, after S1850, may further include: a cover is disposed corresponding to the cavity, wherein the cover has an opening and is connected to the upper surface of the package housing, so as to obtain the pressure sensor shown in fig. 1. In another embodiment, the cover is connected to a portion of the upper surface of the package casing, so in order to reduce the material cost of the package casing, the height of the portion of the upper surface of the package casing not used for connecting the cover may be set to be lower than the height of the portion of the upper surface used for connecting the cover, and this setting may be performed by pressing the encapsulant using a mold with a corresponding shape in step S1830, so as to obtain the upper surfaces of the package casings with different heights (as shown in fig. 6). In another embodiment, the cover can also be connected to a step of the stepped sidewall of the cavity.

In the embodiment, the corners of the cavity are provided with the chamfer structures and/or the side walls of the cavity are provided with the step-shaped structures, so that the protection film can be prevented from being damaged in the manufacturing process, the reliability and controllability of the manufacturing process can be improved, and the manufacturing yield can be improved.

Referring to fig. 20, fig. 20 is a schematic flow chart illustrating a manufacturing method of a pressure sensor according to another embodiment of the present application. The method of the embodiment comprises the following steps:

s2010: a substrate is provided.

S2020: a control device and a pressure sensing device are provided on one side of the substrate.

Steps S2010 to S2020 may refer to the related description of S1810 to S1820, except that a pressure sensing device is further provided in step S2020, wherein the pressure sensing device may be provided on a control device or a substrate.

S2030: and injecting a packaging material into one side of the substrate, and opening the packaging material through a protective film by using a mold to form a packaging shell with a cavity.

In step S2030, reference may be made to the related description of S1830 above. In this embodiment, the mold is opened corresponding to the sensing region of the pressure sensing device, so that the cavity is disposed on the pressure sensing device and the bottom of the cavity is exposed to at least part of the sensing region. Wherein, pressure sensing device can set up isolation structure, and this moment, the mould corresponds this isolation structure and opens the chamber, can guarantee that isolation structure can avoid the mould to act on in order to damage the sensing region on the sensing region from this.

S2040: covering a protective layer to the pressure sensing device within the cavity.

In step S2040, reference may be made to the related description of step S1850, which is not described herein again. It should be understood that, since the cavity of the pressure sensing device is opened in this embodiment, if the bonding wires of the pressure sensing device are not exposed in the cavity, the step S2040 may not be performed, that is, the protection layer is not disposed in the cavity.

In addition, the method can also comprise the following steps: the cover body is arranged corresponding to the cavity. The specific setting manner can refer to the related description of the method embodiment described in fig. 19.

It is understood that fig. 19a to 19h are only schematic illustrations of the pressure sensor structure fabricated in each process, and the actual structure thereof may deviate from that of fig. 19a to 19h, but does not affect the understanding of the fabrication steps of the fabrication method and the pressure sensor structure fabricated thereby.

The above manufacturing method can be used for manufacturing the pressure sensor in the above embodiment of the pressure sensor, so the specific structure of the pressure sensor manufactured by the manufacturing method can refer to the above embodiment of the pressure sensor.

In the above scheme, the usable encapsulation casing that is equipped with the cavity of pressure sensor encapsulates pressure sensing device, and at least one angle of the lateral wall of this cavity is the chamfer structure, and to pressure sensor's preparation process, when utilizing the mould to open the cavity that the encapsulation casing formed the encapsulation casing through the protection film, because the angle of cavity lateral wall is the chamfer structure, can reduce the stress concentration nature that the protection film received at the in-process of opening the cavity, so avoid the damage of protection film, improved the preparation yield.

In the above scheme, the pressure sensor can cover the control device by using the packaging shell, and the cavity in the packaging shell exposes the pressure sensing device, and then the protective layer in the cavity is combined to cover the pressure sensing device or the protective layer is not arranged in the cavity when the exposed pressure sensing device in the cavity is not required to be protected, so that the packaging protection of each device of the pressure sensor is realized.

In the above scheme, the pressure sensor may have a cavity on the pressure sensing device, and at least the packaging shell is used to package each device of the pressure sensor, and the cavity exposes the sensing area of the pressure sensing device for pressure sensing, wherein the upper surface of the pressure sensing device is provided with an isolation structure to prevent an external object from acting on the sensing area, so that effective protection of the pressure sensing device can be realized, effective sensing of pressure is ensured, and reliability of pressure sensing is improved.

In the description above, for purposes of explanation and not limitation, specific details are set forth such as particular system structures, interfaces, techniques, etc. in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

Claims

1. A pressure sensor, comprising:

a substrate;

a pressure sensing device disposed on one side of the substrate;

2. The pressure sensor of claim 1, wherein the isolation structure comprises a protective cavity formed by the upper surface extending toward the lower surface of the pressure sensing device, wherein an upper surface portion, which is a bottom or a sidewall of the protective cavity, is a sensing area of the pressure sensing device.

3. A pressure sensor as claimed in claim 1, wherein the isolation structure comprises a protective cover provided on the upper surface, the protective cover forming a space with the sensing area in the upper surface, and the protective cover being provided with an opening communicating with the space.

4. The pressure sensor of claim 1, wherein the pressure sensing device comprises an outer pressure sensing enclosed cavity and a first pressure membrane, opposite sides of the first pressure membrane being a surface of the sensing region and the outer pressure sensing enclosed cavity, respectively.

5. The pressure sensor of claim 4, wherein the pressure sensing device further comprises a reference pressure sensing enclosed cavity and a second pressure membrane; wherein the two opposite sides of the second pressure membrane are respectively the other surface of the external pressure sensing closed cavity and one surface of the reference pressure sensing closed cavity.

6. The pressure sensor of claim 1, further comprising at least one of:

the control device is arranged on one side of the substrate, the packaging shell covers the control device, and the pressure sensing device is arranged on the substrate or the control device;

and the acceleration sensing device is arranged on one side of the substrate, and part or all of the acceleration sensing device is covered by the packaging shell.

7. The pressure sensor of claim 1, wherein the side walls of the cavity are stepped structures, at least one corner of the stepped structures being a chamfered structure;

and/or the cavity is provided with or without a protective layer for covering the devices in the cavity.

8. The pressure sensor of claim 1, further comprising:

the cover body covers the cavity, and an opening is formed in the position corresponding to the cavity.

9. The pressure sensor of claim 8, wherein the cover is attached to at least a portion of the upper surface of the package housing and/or the cover covers the entire upper surface of the package housing.

10. A method of making a pressure sensor, comprising:

providing a substrate;