TW202044965A - Pressure sensor and manufacturing method thereof - Google Patents

Abstract

The present disclosure provides a pressure sensor and a manufacturing method thereof. The pressure sensor includes: a substrate; a pressure sensing device provided on a side of the substrate; a package housing covering the side of the substrate, wherein a cavity is defined in the package housing, the cavity is disposed on the pressure sensing device, and at least part of a sensing area in an upper surface of the pressure sensing device is exposed at a bottom of the cavity. An isolation structure is provided on the upper surface of the sensing device, and the isolation structure is used to isolate an external object from acting on the sensing area. The present disclosure may improve the production yield of the pressure sensor.

Description

Pressure sensor and manufacturing method thereof

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

Pressure sensors are widely used in consumer electronics, automotive electronics, and industrial electronics. For example, in the automotive electronics industry, applying it to tire pressure monitoring systems can monitor the status of tire pressure and reduce the occurrence of traffic accidents to a large extent.

Since the pressure sensing device of the pressure sensor needs to sense external pressure, the packaging requirements for the pressure sensing device in the pressure sensor are different from the packaging requirements for the control device. Based on the special packaging requirements of the pressure sensor, how to improve the production yield of the pressure sensor is currently a key issue.

The main technical problem solved by the present invention is to provide a pressure sensor and a manufacturing method thereof, which can improve the manufacturing yield of the pressure sensor.

In order to solve the above-mentioned problems, the first aspect of the present invention provides a pressure sensor, which includes: a substrate; a pressure sensing device provided on one side of the substrate; a package housing, the package housing covering the liner On the side of the bottom, and a cavity is provided on the packaging shell, and the cavity is provided on the pressure sensing device, And at least a part of the sensing area in the upper surface of the pressure sensing device is exposed at the bottom of the cavity. An isolation structure is provided on the upper surface of the pressure sensing device, and the isolation structure is used to isolate external objects from acting on the sensing area.

In order to solve the above-mentioned problems, the second aspect of the present invention provides a method for manufacturing a pressure sensor, which includes: providing a substrate; arranging a pressure sensing device on one side of the substrate; wherein the pressure sensing device An isolation structure is provided on the surface, and the isolation structure is used to isolate the sensing area of the upper surface of the pressure sensing device from external objects; inject encapsulation material on the side of the substrate, and use a mold to pass through The protective film opens a cavity to the packaging material corresponding to the isolation structure to form a packaging housing provided with a cavity, wherein the cavity is provided on the pressure sensing device, and the pressure sensing device At least part of the sensing area in the upper surface is exposed at the bottom of the cavity.

In the above solution, the pressure sensor can be provided with a cavity of a package housing on the pressure sensing device, and at least the package housing is used to encapsulate each device of the pressure sensor, and the cavity is used to expose the pressure sensing device. The sensing area is used for pressure sensing, wherein the upper surface of the pressure sensing device is provided with an isolation structure to prevent external objects from acting on the sensing area, so that effective protection of the pressure sensing device can be achieved to ensure the effective pressure Sensing to improve the reliability of pressure sensing.

100‧‧‧Pressure Sensor

110‧‧‧Substrate

111‧‧‧ side

120,1920‧‧‧Control device

121,131,161,171,1921,1931,1961‧‧‧Bonding material

122,132,162,1922,1932,1962‧‧‧Wire bonding

123,136,142,1421,1422‧‧‧Upper surface

130,1960,1930‧‧‧sensing device

133‧‧‧Sensing area

134‧‧‧External pressure sensing closed cavity

135‧‧‧First pressure membrane

137‧‧‧Isolation structure

1371‧‧‧Protection cavity

1372‧‧‧Protection cover

13721‧‧‧Space

13722‧‧‧Open

138‧‧‧Reference pressure sensing closed cavity

139‧‧‧Second pressure membrane

140,1940‧‧‧Packaging shell

141,1941‧‧‧cavity

1411‧‧‧Bottom

1412‧‧‧Wall

1412a‧‧‧Step

1412a1‧‧‧End angle

1412b‧‧‧Connection

1412c‧‧‧Angle

150,1950‧‧‧Protection layer

160‧‧‧Sensing device

172‧‧‧Open

1910‧‧‧Substrate

1948‧‧‧Mould

1949‧‧‧Protective film

h1,h2‧‧‧height

S1810, S1820, S1830, S1840, S1850, S2010, S2020, S2030, S2040‧‧‧Step

Figure 1 is a schematic side sectional view of the first embodiment of the pressure sensor of the present invention.

Figure 2 is a schematic side sectional view of the first embodiment of the pressure sensing device of the pressure sensor of the present invention.

Figure 3 is a schematic side sectional view of the second embodiment of the pressure sensor of the present invention.

Figure 4 is a schematic side sectional view of the third embodiment of the pressure sensor of the present invention.

Figure 5 is a schematic side sectional view of the fourth embodiment of the pressure sensor of the present invention.

Figure 6 is a schematic side sectional view of the fifth embodiment of the pressure sensor of the present invention.

Figure 7 is a schematic side sectional view of the sixth embodiment of the pressure sensor of the present invention.

Figure 8 is a schematic side sectional view of the seventh embodiment of the pressure sensor of the present invention.

Figure 9 is a schematic side sectional view of the eighth embodiment of the pressure sensor of the present invention.

Figure 10 is a schematic side sectional view of the ninth embodiment of the pressure sensor of the present invention.

Figure 11 is a schematic side sectional view of the tenth embodiment of the pressure sensor of the present invention.

Figure 12 is a schematic side sectional view of the second embodiment of the pressure sensing device of the pressure sensor of the present invention.

Figure 13 is a schematic side sectional view of the third embodiment of the pressure sensing device of the pressure sensor of the present invention.

Figure 14 is a schematic side sectional view of the fourth embodiment of the pressure sensing device of the pressure sensor of the present invention.

Figure 15 is a schematic side sectional view of the fifth embodiment of the pressure sensing device of the pressure sensor of the present invention.

Figure 16 is a schematic side sectional view of the sixth embodiment of the pressure sensing device of the pressure sensor of the present invention.

Figure 17 is a schematic side sectional view of the seventh embodiment of the pressure sensing device of the pressure sensor of the present invention.

Fig. 18 is a schematic flow chart of an embodiment of the manufacturing method of the pressure sensor of the present invention.

Figures 19a to 19h are schematic diagrams of the structure of a pressure sensor manufactured by corresponding steps in an embodiment of the manufacturing method of the pressure sensor of the present invention;

FIG. 20 is a schematic flowchart of another embodiment of the manufacturing method of the pressure sensor of the present invention.

The solutions of the embodiments of the present invention will be described in detail below in conjunction with the drawings in the specification.

In the following description, for the purpose of illustration rather than limitation, specific details such as a specific system structure, interface, technology, etc. are proposed for a thorough understanding of the present invention.

The term "and/or" in this article is only an association relationship describing related objects, which means that there can be three relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone. three conditions. In addition, the character "/" in this text generally indicates that the associated objects before and after are in an "or" relationship. The multiple or several mentioned in the present invention should be understood as two or more than two.

The pressure sensor described herein can be used in any pressure detection system, for example, can be used in a tire pressure monitoring system. Specifically, the pressure sensor may be a tire pressure monitoring chip.

Please refer to Fig. 1, which is a schematic side sectional view of an embodiment of the pressure sensor of the present invention. In this embodiment, the pressure sensor 100 includes a substrate 110, a control device 120, a pressure sensing device 130, a packaging shell 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 on one side 111 of the substrate 110. In a specific application, the control device 120 may be fixed on the substrate 110 through the first device bonding material 121, and may be electrically connected to the substrate 110 through a bonding wire 122. The control device 120 may specifically be a Microcontroller Unit (MCU) chip.

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

The pressure sensing device 130 is provided with a sensing area for sensing external pressure. Specifically, referring to Figure 2, the pressure sensing device 130 includes The sensing area 133 and the external pressure sensing enclosed cavity 134, the sensing area 133 corresponds to a surface of the external pressure sensing enclosed cavity 134 (it is understood that the surface of the sensing enclosed cavity described herein may be the sensing area Measure the surface of any orientation in the enclosed cavity). Specifically, the sensing area 133 is formed by the first pressure film 135, and a surface of the sensing area 133 and the external pressure sensing sealed cavity 134 are opposite sides of the first pressure film 135, respectively.

The package housing 140 is located on the side 111 of the substrate 110 and is provided with a cavity 141, and at least a part of the sensing area 133 of the pressure sensing device 130 is exposed at the bottom 1411 of the cavity 141. In a specific application, the packaging shell 140 can be any material that can protect the device, and is usually a harder material such as plastic.

Specifically, as shown in Figure 1, the package housing 140 can cover the devices on the side 111 of the substrate 110 (which can be understood as covering some or all of the devices on the side 111 of the substrate 110) such as the control device 120 The following sensing device 130 and its bonding wires are used to package and protect devices other than the pressure sensing device 130. For example, the cavity 141 is provided on the control device 120, and the bottom 1411 of the cavity 141 is exposed to control At least part of the upper surface of the device 120, and the pressure sensing device 130 is provided on the upper surface of the control device 120 at the bottom 1411 of the cavity. Of course, as shown in Figure 7, the cavity 141 is provided on the substrate 110, and the bottom 1411 of the cavity 141 exposes part of the upper surface of the substrate 110, and the pressure sensing device 130 is provided on the bottom 1411 of the cavity. On the upper surface of the substrate 110; or, as shown in Figure 9, the package housing 140 may also partially cover the pressure sensing device 130. For example, the cavity 141 is provided on the upper surface of the pressure sensing device 130. It is sufficient that the measurement area 133 is exposed on the bottom 1411 of the cavity 141. For encapsulated shell 140 covers at least part of the devices on the substrate 100, and then the pressure sensing device 130 is packaged and protected by the cavity 141 through the following protective layer. Compared with directly using the protective layer to package all the devices on the substrate, the protective layer material can be reduced. The use of the protective layer reduces the packaging cost of the protective layer, and compared with the protective layer, the use of the packaging shell can better protect the non-pressure sensing device, which can improve the packaging reliability, and the combination of the packaging shell and the protective layer Packaging can reduce packaging process control requirements and improve production yield. It should be noted that, in the embodiment shown in 9, the cavity 141 is provided on the pressure sensing device 130, and the following protective layer can be provided or provided in the cavity according to actual needs, that is, the pressure sensor can include or The following protective layers are not included. For example, if the bonding wires of the pressure sensing device 130 are not exposed in the cavity, the following protective layer may not be provided in the cavity. In this case, the packaging cost is further reduced and the sensitivity of the sensing area of the pressure sensing device to pressure is improved.

It is understandable that the package housing 140 may not cover all or part of the devices on the substrate 110. For example, the package housing 140 is provided on the outer periphery of one side 111 of the substrate 110 to surround all the devices on the substrate 110. , And all devices are exposed at the bottom 1411 of the cavity 141. At this time, all devices on the substrate are covered by the following protective layer for packaging protection.

The protective layer 150 is used to cover the devices in the cavity 141. As shown in FIG. 1, the protective layer 150 covers the pressure sensing device 130 and its bonding wires 132. It can be understood that, if there are other devices in the cavity 141, the protective layer 150 also covers the other devices and their associated bonding wires. Specifically, the protective layer 150 may be a gel or other material with certain elasticity to be able to transmit external pressure to the pressure sensing device 130. For example, in the process of packaging the pressure sensor 100, glue is injected into the cavity 141 to a certain height to cover the cavity 141 Then, the glue is cured to form a gel to protect the devices in the cavity 141. The external pressure of the pressure sensor of this embodiment is transferred to the sensing area of the pressure sensing device 130 through the protective layer 150, so that the external pressure can be measured.

Please continue to combine with Figure 1. The pressure sensor 100 can also be used to detect data other than pressure. Therefore, the pressure sensor 100 can also include at least one sensing device 160 for detecting other data. The at least one sensing device The device 160 is provided on one side 111 of the substrate 110. As shown in FIG. 1, the entirety of each sensing device 160 is covered by the packaging case 140. It should be understood that, in other embodiments, the sensing device 160 may also be partially covered by the package housing 140 (for example, the package housing 140 only covers the welding place of the sensing device 160 and its bonding wires), and the sensing device 160 is not packaged. The part covered by the housing 140 may be covered by a protective layer or other materials or directly exposed. Specifically, the sensing device 160 may be a sensing device such as acceleration and temperature. In a specific application, the pressure sensor 100 includes an acceleration sensing device 160 in addition to the aforementioned structure, which serves as a tire pressure monitoring chip capable of monitoring tire pressure and acceleration.

The at least one sensing device 160 may be integrated in a device group, specifically, it may be integrated in a stacked or tiled manner. In addition, as shown in FIG. 1, the at least one sensing device 160 may 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 the upper surface of the control device 120. In a specific application, the sensing device 160 may be fixed on the substrate 110 or the control device 120 through the third device bonding material 161, and may be electrically connected to the substrate 110 or the control device 120 through a bonding wire 162. It is understandable that the pressure sensor 100 can be equipped with a sensing device 160 according to actual needs. In some In the embodiment, the pressure sensor 100 may not be provided with the sensing device 160, so it is not limited here.

It is understandable that the above-mentioned first device bonding material, second device bonding material, and third device bonding material may be the same or different bonding materials, and specifically may be conductive glue, non-conductive glue, adhesive film and bottom Filler, molded plastic, etc. The aforementioned control device, pressure sensing device, and sensing device may specifically be control wafers, pressure sensing wafers and related sensing wafers. The above-mentioned control device, pressure sensing device, sensing device and other devices can be arranged on the substrate or other devices by means of flip-chip welding.

Please continue to refer to FIG. 1. In some embodiments, at least one corner of the side wall 1412 of the cavity 141 of the package housing 140 may be a chamfered structure. As shown in Figure 1, all corners of the sidewall 1412 of the cavity 141 may be chamfered structures. For the manufacturing process of the pressure sensor, the cavity 141 is usually formed by pressing the packaging material with a mold, and the shape of the side wall 1412 of the cavity 141 depends on the shape of the mold. In order to protect the device or substrate at the position corresponding to the cavity 141, a mold is usually used to press the packaging material through a protective film to reduce the pressure of the mold on the device or substrate in the formed cavity. In order to avoid damage to the protective film when the mold presses the packaging material through the protective film, at least part of the corners of the mold can be set in a chamfered structure, and finally the corresponding corner of the cavity 141 is a chamfered structure. As a result, the stress concentration of the protective film during the opening process can be reduced, the damage of the protective film can be avoided, the service life of the protective film during the production process can be increased, the alarm rate caused by the damage of the protective film during the production process can be reduced, and the production yield can be improved (Also called package yield).

Please continue to refer to FIG. 1. In some embodiments, the sidewall 1412 of the cavity 141 may be a stepped structure. For example, the side wall 1412 includes multiple Steps 1412a, the multiple steps 1412a are connected in sequence to form a stepped structure. Wherein, at least one corner in the stepped structure is a chamfered structure, for example, the end corner 1412a1 of each step 1412a and the connection 1412b between the step 1412a are chamfered structures. In addition, the step 1412a can be set in any shape according to actual needs. For example, the step 1412a shown in Figure 1 is rectangular or almost rectangular, and the upper surface of the step 1412a can be level (shown in Figure 1) or have a certain angle with the level surface. . In addition, the angle β formed by the junction 1412b between the steps 1412a can be set to a right angle (as shown in Figure 1), an obtuse angle (as shown in Figure 3) or an acute angle (as shown in Figure 4) according to actual needs. . In this embodiment, the side wall of the cavity 141 is set in a stepped shape, so that the depth of each step of the side wall is lower than the depth of the entire side wall of the non-stepped shape (as shown in Figure 5), so that the protective film can also be affected during the packaging process. The stress concentration is reduced to avoid damage to the protective film, increase the service life of the protective film during the production process, reduce the alarm rate due to the damage of the protective film during the production process, and improve the production yield.

It can be understood that in the embodiment where the sidewalls are stepped, the height of a certain step 1412a can be used as the reference height of the protective layer 150, that is, the height of the protective layer is added to a certain step 1412a when the protective layer 150 is added. The height. Furthermore, as shown in Figure 4, the junction 1412b between the steps 1412a can be a groove extending toward the substrate 110, so when a protective layer is added, the height of a certain step 1412a can be used as a reference for the protective layer After adding the protective layer material heated to liquid into the cavity 141 to the height of a certain step 1412a, the addition is stopped, and the excess protective layer material can flow into the groove of the connection 1412b.

In addition, the side wall 1412 of the cavity 141 may not be provided with a stepped structure. As shown in FIG. 5, the side wall 1412 is a relatively large depth. Steps. Wherein, the corner 1412c of the side wall 1412 can be, but is not limited to, a chamfered structure.

Please continue to refer to FIG. 1. In some embodiments, in order to further improve the protection of the components in the cavity 141, the pressure sensor 100 may further include a cover 170. The cover 170 covers the upper part of the cavity 141, and an opening 172 is provided at a position corresponding to the cavity 141. The cover 170 is used to further protect the devices in the cavity 141. The external pressure of the pressure sensor in this embodiment changes the air pressure in the cavity through the opening, and the pressure sensing device 130 detects the external pressure by sensing the air pressure in the cavity 141. Of course, in other embodiments, the pressure sensor 100 may not be provided with the cover 170, which is not limited here.

Specifically, the cover 170 is connected to at least a part of the upper surface 142 of the packaging shell 140 and extends above the cavity 141 through the connection portion, so as to cover the cavity 141. Specifically, the cover 170 may be connected by the cover bonding material 171. Since the upper surface 142 of the package housing 140 has a relatively large area, the cover 170 can be bonded with a relatively large area to improve the reliability of the connection of the cover, and the process is simple, the package housing has less warpage, and heat dissipation. More capable. It can be understood that, in order to achieve the maximum connection reliability, the upper surface of the packaging housing 140 can be used as the connection area connected with the cover 170, that is, to cover the cover bonding material 171 and the connection cover 170. However, when the area of the upper surface 142 of the packaging shell 140 is relatively large, the cover 170 may optionally be connected with a part of the upper surface 142 of the packaging shell 140, wherein at least a part of the upper surface 1422 not connected with the cover 170 The height of is equal to or lower than the height of the upper surface 1421 connected with the cover 170. For example, as shown in FIG. 1, the height of the upper surface 1422 of the package housing 140 that is not connected to the cover 170 is equal to the height of the upper surface that is connected to the cover 170 Or, as shown in Figure 6, the height h1 of the upper surface 1422 of the portion of the package housing 140 that is not connected to the cover 170 is lower than the height h2 of the upper surface 1421 connected to the cover 170 to reduce The use of packaging materials reduces costs.

It can be understood that when the cover 170 is connected to at least part of the upper surface of the packaging shell 140, the cover 170 can be arranged to cover the entire upper surface of the packaging shell 140. As shown in FIG. The upper surface of 140 that is not connected to the cover 170 is also covered by the cover 170. By covering the entire upper surface of the casing 140 with the cover, the warpage of the casing can be made smaller.

In addition, in the embodiment where the side wall 1412 is set in a stepped shape, the cover 170 may also be connected to a step of the side wall 1412, for example, connected to the step by a cover bonding material, thereby reducing the area of the cover 170 , Reduce costs. In addition, the cover bonding material can be implemented by using device bonding materials, such as glue, double-sided tape, etc.

Referring to FIGS. 7 and 8, the pressure sensing device 130 of the pressure sensor 100 may be disposed on the surface of the side 111 of the substrate 110. Specifically, the cavity 141 of the package housing 140 is disposed on the substrate 110, and the bottom 1411 of the cavity 141 exposes part of the surface of the substrate 110, and the pressure sensing device 130 is disposed on the substrate 110 at the bottom 1411 of the cavity. On the surface, the protective layer 150 covers the pressure sensing device 130 and its bonding wires 132. Wherein, for the embodiment shown in FIG. 8, the sensing device 130 may be disposed on the upper surface of the control device 120.

Referring to FIGS. 9-11, the cavity 141 of the pressure sensor 100 is provided on the pressure sensing device 130, and a part of the sensing area of the pressure sensing device 130 is exposed at the bottom 1411 of the cavity 141. Among them, in some embodiments, as shown in Figure 9, the pressure sensing device 130 may be provided on the upper surface of the control device 120. The sensing device 160 can be disposed on the substrate 110. Of course, the sensing device 160 and the pressure sensing device 130 can also be separately disposed on the control device 120, which is not limited here. In some embodiments, as shown in FIG. 10, the pressure sensing device 130 and the control device 120 may also be separately disposed on the substrate 110. In some embodiments, as shown in FIG. 11, the pressure sensing device 130 and the control device 120 may be separately disposed on the substrate 110, and the sensing device 160 may be disposed on the upper surface of the control device 120. Among them, for the embodiment in which the cavity 141 of the pressure sensor 100 is provided on the pressure sensing device 130, a protective layer may be provided or not provided in the cavity 141 according to actual requirements.

It should be noted that in the above embodiment, the cavity side wall 1412 of the pressure sensor can be set or not set to the above-mentioned chamfered structure and stepped structure according to requirements. In addition, the control device 120, the sensing device 160 and the cover 170 can also be selected and set according to the actual requirements of the pressure sensor, which is not limited here. For example, in one embodiment, the pressure sensing device may be separately packaged to obtain a pressure sensor, and other devices such as the control device and the sensing device may be separately packaged in another control system. In this case, the pressure sensor may not be equipped with a control system. Devices and sensing devices. However, compared to packaging the control device separately, the above embodiment packages the pressure sensing device together with the control device and the sensing device, etc., to obtain a smaller system in package and reduce the package size. , So that the control device and the pressure sensing device can be directly interconnected at the package level, and the package parasitic between the devices is reduced.

For the above embodiments, in order to prevent external objects from acting on the sensing area of the pressure sensing device 130 to damage the sensing area, please refer to Figures 12-14, the upper surface 136 of the pressure sensing device 130 Also has a partition 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 pressure sensing device is arranged in the cavity of the packaging housing, during the manufacturing process, a mold is required to act on the packaging material through the protective film to form a cavity on the pressure sensing device. The structure 137 can be used to prevent the mold from acting on the sensing area to damage the sensing area.

In some embodiments, as shown in FIG. 12, the isolation structure 137 includes a protection cavity 1371 formed by extending from the upper surface 136 to the lower surface of the pressure sensing device 130, wherein the bottom or side walls of the protection cavity 137 are The surface part is the sensing area 133 of the pressure sensing device. For example, in an embodiment in which the external pressure sensing sealed cavity 134 is provided at the bottom of the protection cavity 137, the upper surface of the bottom of the protection cavity 137 is a side of the first pressure membrane 135, and a part of the surface of the external pressure sensing sealed cavity 134 As the other side of the first pressure film 135; for the embodiment in which the external pressure sensing sealed cavity 134 is provided on the side of the protection cavity 137, the upper surface part of the side wall of the protection cavity 137 is one side of the first pressure film 135, and the outer Part of the surface of the pressure sensing sealed cavity 134 serves as the other side of the first pressure membrane 135

In some embodiments, as shown in FIG. 13, the isolation structure 137 includes a protective cover 1372 provided on the upper surface 136, the protective cover 1372 and the sensing area 133 on the upper surface 136 form a space 13721, and the protective cover 1372 An opening 13722 communicating with the space 13721 is provided. Specifically, the upper surface of the pressure sensing device 130 is provided with a first pressure film 135, wherein one side of the first pressure film 135 is used as the sensing area 133 in the upper surface 136, and the other side of the first pressure film 135 is the outside. The pressure senses part of the surface of the enclosed cavity 134.

In some embodiments, as shown in FIG. 14, the isolation structure 137 may include the aforementioned protective cavity 1371 and a protective cover 1372.

In the above embodiment with isolation structure, the use of the protection cavity 1371 and/or the protection cover 1372 in the isolation structure can avoid the use of molds to open the pressure sensing device during the manufacturing process of the pressure sensor. The damage to the first pressure membrane 135 can protect the first pressure membrane 135.

Please refer to Figures 15-17. Specifically, Figure 15 shows an example in which the isolation structure includes the aforementioned protective cavity 1371, and Figure 16 shows the isolation structure includes the aforementioned protective cover 1372. Figure 17 What comes out is an embodiment in which the isolation structure includes the aforementioned protective cavity 1371 and the protective cover 1372. In order to improve the accuracy of pressure measurement of the pressure sensing device 130, the pressure sensing device 130 is provided with an external pressure sensing sealed cavity 134 and a first pressure membrane 135, as well as a reference pressure sensing sealed cavity 138 and a first pressure membrane. Two pressure film 139. The opposite sides of the second pressure membrane 139 are the other surface of the external pressure sensing sealed cavity 134 and a surface of the reference pressure sensing sealed cavity 138 respectively. The reference pressure sensing sealed cavity 138 may be a vacuum setting. When performing pressure measurement, the first pressure film 135 and the second pressure film 139 can be used to measure the current sensing values of the external pressure sensing enclosed cavity 134 and the reference pressure sensing enclosed cavity 138; according to the reference pressure sensing the enclosed cavity The current sensed value of 138 and the reference sensed value of the reference pressure-sensing sealed cavity 138 measured before packaging are used to compensate the current sensed value of the external pressure-sensing sealed cavity 134 to obtain an accurate measured pressure value. The compensation structure can ensure accurate measurement of pressure data even when the package shell 130 is warped and other abnormal conditions.

It is understandable that the pressure sensing device 130 can choose to set the aforementioned isolation structure and the reference pressure sensing closed cavity according to actual needs, for example, in an actual In an embodiment, the pressure sensing device 130 may not be provided with an isolation structure, and only a reference pressure sensing sealed cavity is provided. Therefore, the specific structure of the pressure sensing device is not limited here. Please refer to FIG. 18. FIG. 18 is a schematic flowchart of an embodiment of the manufacturing method of the pressure sensor of the present invention. In this embodiment, the manufacturing method includes the following steps:

S1810: Provide a substrate.

As shown in FIG. 19a, a substrate 1910 is provided. Among them, the substrate 1910 can be, but is not limited to, a substrate such as a metal lead frame, a plastic substrate, and a ceramic substrate.

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

As shown in FIG. 19b, a control device 1920 is provided on one side of the substrate 1910, wherein the first device bonding material 1921 can be used to bond the control device 1920 on the substrate 1910.

It is understandable that when the pressure sensor needs to sense other data besides the pressure, this step also includes arranging at least one sensing device 1960 on one side of the substrate 1910, where a third device can be used for bonding. The bonding material 1961 bonds the sensing device 1960 on the substrate 1910. Of course, in other embodiments, this step may also include arranging at least one sensing device 1960 on the control device 1920, so that the sensing device 1960 is stacked on the control device 1920.

Continuing to refer to Figure 19c, after setting the related devices, this step may also include using bonding wires to connect the related devices. For example, a bonding wire 1922 is used to connect the control device 1920 to the substrate 1910, and a bonding wire 1962 is used to connect the sensing device 1960 to the control device 1920.

S1830: Inject a packaging material on the side of the substrate, and use a mold to open a cavity on the packaging material through a protective film to form a packaging shell provided with a cavity.

As shown in Figure 19d, the packaging material 1940 is injected on one side of the substrate 1910, and the mold 1948 is used to press the packaging material 1940 through the protective film 1949 to open the cavity, forming a cavity as shown in Figure 19e. A packaging case 1940 provided with a cavity 1941. Wherein, the packaging material can be plastic, so the cavity can be formed by molding and opening the cavity.

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

In some embodiments, at least one corner of the side wall of the cavity 1941 is a chamfered structure. Specifically, a mold 1948 with at least one corner of a chamfered structure is used to open the encapsulant 1940 through the protective film 1949 to form a cavity 1941 with a corresponding corner of the chamfered structure. Therefore, the chamfering can reduce the stress concentration of the protective film, thereby avoiding damage to the protective film, and improving the manufacturing yield.

In some embodiments, the sidewall of the cavity 1941 may be provided in a stepped structure. Specifically, a mold 1948 with a stepped sidewall corresponding to the side wall is used to step open the encapsulation material 1940 through a protective film 1949 to form a cavity 1941 with a stepped sidewall. Therefore, the stepped structure can make the depth of each step lower than the depth of the overall side wall, so the stress concentration on the protective film can be reduced, thereby avoiding damage to the protective film and facilitating the opening of the cavity. Process control in the process to improve production yield. In addition, the steps of the stepped structure can also be used as the height reference surface for adding the protective layer.

In some embodiments, the formed package housing 1940 covers 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 cavity The bottom of 1941 exposes part of the surface of the control device 1920 or part of the surface of the substrate 1910.

S1840: Set a pressure sensing device in the cavity.

As shown in FIG. 19f, a pressure sensing device 1930 is provided on the control device 1920 at the bottom of the cavity 1941, wherein a second device bonding material 1931 may be used to press the pressure sensing device 1930 on the control device 1920. Of course, in other embodiments where the substrate 1910 is exposed at the bottom of the cavity 1941, the pressure sensing device 1930 may be provided on the substrate 1910 at the bottom of the cavity 1941.

Continuing to refer to FIG. 19g, after setting the pressure sensing device 1930, this step may further include connecting the pressure sensing device 1930 with a bonding wire. For example, a bonding wire 1932 is used to connect the pressure sensing device 1930 and the control device 1920. Of course, in other embodiments where the substrate 1910 is exposed at the bottom of the cavity 1941, after the pressure sensing device 1930 is provided on the substrate 1910 at the bottom of the cavity 1941, the pressure sensing device 1930 can be connected to the liner by the bonding wire 1932. The bottom 1910 is connected.

S1850: Cover the device in the cavity with a protective layer.

As shown in FIG. 19h, a protective layer 1950 such as gel is injected into the cavity 1941 to cover the pressure sensing device 1930 and its bonding wires in the cavity 1941. It is understandable that in order to protect the pressure sensing device 1930 in the cavity 1941 And its bonding wires, the height of the protective layer should be higher than the height of the pressure sensing device 1930 and its bonding wires.

In some embodiments, after S1850, it may further include: setting a cover corresponding to the cavity position, wherein the cover is provided with an opening and is connected to the upper surface of the packaging shell to obtain the pressure as shown in Figure 1. Sensor. In another embodiment, the cover body is connected to part of the upper surface of the packaging shell. Therefore, in order to reduce the material cost of the packaging shell, the height of the upper surface of the part of the packaging shell that is not used for connecting the cover body can be set lower than the With regard to the height of the upper surface of the connecting cover, this setting can use a mold of corresponding shape to press the packaging material in step S1830 to obtain the upper surface of the packaging shell with different heights (as shown in Figure 6). In still another embodiment, the cover can also be connected to a step of the stepped side wall of the cavity.

In this embodiment, by setting the corners of the cavity with a chamfer structure and/or setting the side wall of the cavity with a stepped structure, damage to the protective film during the manufacturing process can be avoided, so the reliability and controllability of the manufacturing process are improved, and the manufacturing Yield rate.

Please refer to FIG. 20. FIG. 20 is a schematic flowchart of another embodiment of the manufacturing method of the pressure sensor of the present invention. The method of this embodiment includes:

S2010: Provide a substrate.

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

The steps S2010-S2020 can refer to the relevant descriptions of the above S1810-S1820. The difference is that the pressure sensing device is also set first in step S2020, wherein the pressure sensing device can be set on the control device or the substrate.

S2030: Inject a packaging material on one side of the substrate, and use a mold to open a cavity on the packaging material through a protective film to form a packaging shell provided with a cavity.

For step S2030, reference may be made to the related description of S1830. However, in this embodiment, the mold opens a cavity corresponding to the sensing area of the pressure sensing device, so that the cavity is disposed on the pressure sensing device and at least part of the sensing area is exposed at the bottom of the cavity. Wherein, the pressure sensing device can be provided with an isolation structure. At this time, the mold opens the cavity corresponding to the isolation structure, thereby ensuring that the isolation structure can prevent the mold from acting on the sensing area to damage the sensing area.

S2040: Cover the pressure sensing device in the cavity with a protective layer.

For step S2040, reference may be made to the related description of S1850 above, so it will not be repeated here. 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, step S2040 may not be performed, that is, no protective layer is provided in the cavity.

In addition, the method may further include: setting a cover corresponding to the position of the cavity. For the specific setting method, refer to the related description of the method embodiment shown in Figure 19.

It is understandable that Fig. 19a-Fig. 19h are only schematically showing the structure of the pressure sensor produced in each process. The actual structure may differ from Fig. 19a-Fig. 19h, but it does not affect Understanding of the manufacturing steps of the manufacturing method and the structure of the pressure sensor obtained by the manufacturing method.

The above-mentioned manufacturing method can be used to manufacture the pressure sensor in the above-mentioned pressure sensor embodiment. Therefore, the specific structure of the pressure sensor manufactured by this manufacturing method can refer to the above-mentioned pressure sensor embodiment.

In the above-mentioned solution, the pressure sensor can be packaged with a packaging housing provided with a cavity to package the pressure sensing device, and at least one corner of the side wall of the cavity is a chamfered structure. For the pressure sensor during the manufacturing process When the mold is used to open the encapsulation shell through the protective film to form the cavity of the encapsulation shell, since the corners of the cavity side walls are chamfered, the stress concentration of the protective film during the cavity opening process can be reduced, so protection is avoided The damage of the film improves the production yield.

In the above solution, the pressure sensor can use the packaging shell to cover the control device, and the cavity in the packaging shell exposes the pressure sensing device, and then combines the protective layer in the cavity to cover the pressure sensing device or the cavity When the pressure sensing device exposed in the body does not need to be protected, there is no protective layer in the cavity to realize the packaging protection of each device of the pressure sensor. Compared with all the devices that use the protective layer to encapsulate the pressure sensor, the packaging shell and The combination of the protective layer or the direct use of the packaging shell to encapsulate can reduce the material cost of the protective layer, and the use of the packaging shell to achieve more reliable protection of the control device improves the packaging reliability of the pressure sensor.

In the above solution, the pressure sensor can be provided with a cavity of a package housing on the pressure sensing device, and at least the package housing is used to encapsulate each device of the pressure sensor, and the cavity is used to expose the pressure sensing device. The sensing area is used for pressure sensing, wherein the upper surface of the pressure sensing device is provided with an isolation structure to prevent external objects from acting on the sensing area, so that effective protection of the pressure sensing device can be achieved to ensure the effective pressure Sensing to improve the reliability of pressure sensing.

In the above description, for the purpose of illustration rather than limitation, specific details such as specific system structure, interface, technology, etc. are proposed for a thorough understanding of the present invention. However, it should be clear to those skilled in the art that the present invention can also be implemented in other embodiments without these specific details. In other cases, Detailed descriptions of well-known devices, circuits, and methods are omitted to avoid unnecessary details from obstructing the description of the present invention.

130‧‧‧Pressure sensing device

133‧‧‧Sensing area

134‧‧‧External pressure sensing closed cavity

135‧‧‧First pressure membrane

136‧‧‧Upper surface

137‧‧‧Isolation structure

1371‧‧‧Protection cavity

Claims (10)

A pressure sensor, including: Substrate A pressure sensing device arranged on one side of the substrate; The packaging shell covers the one side of the substrate, and the packaging shell is provided with a cavity, the cavity is provided on the pressure sensing device, and the At least part of the sensing area in the upper surface of the pressure sensing device is exposed at the bottom of the cavity; Wherein, an isolation structure is provided on the upper surface of the pressure sensing device, and the isolation structure is used to isolate an external object from acting on the sensing area. The pressure sensor according to claim 1, wherein the isolation structure includes a protection cavity formed by extending the upper surface to the lower surface of the pressure sensing device, wherein, as the bottom of the protection cavity Or the upper surface part of the side wall is the sensing area of the pressure sensing device. The pressure sensor according to claim 1, wherein the isolation structure includes a protective cover provided on the upper surface, and a space is formed between the protective cover and the sensing area on the upper surface, and The protective cover is provided with an opening communicating with the space. The pressure sensor according to claim 1, wherein the pressure sensing device includes an external pressure sensing sealed cavity and a first pressure membrane, and opposite sides of the first pressure membrane are the sensing regions respectively And the external pressure sensing a surface of the closed cavity. The pressure sensor according to claim 4, wherein the pressure sensing device further includes a reference pressure sensing closed cavity and a second pressure membrane; wherein, the first The opposite sides of the two pressure films are the other surface of the external pressure sensing sealed cavity and one surface of the reference pressure sensing sealed cavity. The pressure sensor according to claim 1, further comprising at least one of the following: a control device provided on the one side of the substrate, wherein the packaging casing covers the control device, and The pressure sensing device is arranged on the substrate or the control device; An acceleration sensing device arranged on one side of the substrate, part or all of the acceleration sensing device is covered by the packaging casing. The pressure sensor according to claim 1, wherein the side wall of the cavity has a stepped structure, and at least one corner of the stepped structure is a chamfered structure; And/or, the cavity is provided with or without a protective layer, and the protective layer is used to cover the devices in the cavity. The pressure sensor as described in claim 1, further comprising: The cover body covers the upper part of the cavity and has an opening corresponding to the position of the cavity. The pressure sensor according to claim 8, wherein the cover is connected to at least a part of the upper surface of the packaging casing, and/or the cover covers the entire upper surface of the packaging casing. A manufacturing method of a pressure sensor includes: Provide a substrate; A pressure sensing device is provided on one side of the substrate; wherein an isolation structure is provided on the upper surface of the pressure sensing device, and the isolation structure is used to isolate external objects from acting on the upper surface of the pressure sensing device. Sensing area The packaging material is injected into the one side of the substrate, and the packaging material is opened with a mold through the protective film corresponding to the isolation structure to form a packaging housing provided with a cavity, wherein the cavity It is arranged on the pressure sensing device, and at least a part of the sensing area in the upper surface of the pressure sensing device is exposed at the bottom of the cavity.

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