Package body, preparation method thereof, terminal, and electronic device

Abstract

A package body includes: a substrate; a plurality of electronic components, arranged on the substrate; a package material layer, located on the substrate and packaging the plurality of electronic components; a low frequency shielding conductive structure, embedded in the package material layer, where the low frequency shielding conductive structure is located on a side of the package material layer away from the substrate and is spaced apart from the plurality of electronic components, the low frequency shielding conductive structure is provided with a plurality of through holes, an area of an opening of each of at least some of the through holes is less than 1 mm*1 mm, and a thickness of the low frequency shielding conductive structure is not less than 10 m.

Claims

1. A package body, comprising: a substrate; a plurality of electronic components, arranged on the substrate, wherein the plurality of electronic components comprises electronic components configured to emit low frequency electromagnetic waves, and a frequency of the low frequency electromagnetic waves is less than 10 MHz; a package material layer, located on the substrate and packaging the plurality of electronic components; and a low frequency shielding conductive structure, embedded in the package material layer, wherein the low frequency shielding conductive structure is located on a side of the package material layer away from the substrate and is spaced apart from the plurality of electronic components, wherein the low frequency shielding conductive structure covers at least the electronic components that are configured to emit the low frequency electromagnetic waves, and a region of the low frequency shielding conductive structure covering the electronic components that are configured to emit the low frequency electromagnetic waves is meshed, wherein the low frequency shielding conductive structure is provided with a plurality of through holes, wherein an area of an opening of each of at least some of the through holes is less than 1 mm*1 mm, and wherein a thickness of the low frequency shielding conductive structure is not less than 10 m.

2. The package body of claim 1, wherein the low frequency shielding conductive structure is made of a conductive material with a conductivity not lower than 510.sup.6 S/m or a magnetic permeability greater than or equal to 410.sup.7 H/m.

3. The package body of claim 1, wherein the area of the opening of each through hole in the region covering the electronic components that are configured to emit the low frequency electromagnetic waves in the low frequency shielding conductive structure is less than 1 mm*1 mm.

4. The package body of claim 1, wherein the plurality of through holes of the low frequency shielding conductive structure are arranged in an array.

5. The package body of claim 1, further comprising a conformal shielding layer arranged on an outer surface of the package material layer, wherein the conformal shielding layer is a nanoscale conductive metal layer, and wherein the low frequency shielding conductive structure is connected to the conformal shielding layer.

6. The package body of claim 5, further comprising a complete conductive thin layer arranged between the low frequency shielding conductive structure and the conformal shielding layer.

7. The package body of claim 1, further comprising a grounded conductive partition wall embedded in the package material layer, wherein the grounded conductive partition wall divides the package body into at least two compartments and is configured to weaken coupling of electromagnetic waves between different compartments.

8. The package body of claim 1, further comprising a complete conductive thin layer that covers a surface of the low frequency shielding conductive structure away from the substrate.

9. A terminal, comprising: a housing; and a package body accommodated in the housing, wherein the package body comprises: a substrate; a plurality of electronic components, arranged on the substrate, wherein the plurality of electronic components comprises electronic components configured to emit low frequency electromagnetic waves, and a frequency of the low frequency electromagnetic waves is less than 10 MHz; a package material layer, located on the substrate and packaging the plurality of electronic components; and a low frequency shielding conductive structure, embedded in the package material layer, wherein the low frequency shielding conductive structure is located on a side of the package material layer away from the substrate and is spaced apart from the plurality of electronic components, wherein the low frequency shielding conductive structure covers at least the electronic components that are configured to emit the low frequency electromagnetic waves, and a region of the low frequency shielding conductive structure covering the electronic components that are configured to emit the low frequency electromagnetic waves is meshed, wherein the low frequency shielding conductive structure is provided with a plurality of through holes, wherein an area of an opening of each of at least some of the through holes is less than 1 mm*1 mm, and wherein a thickness of the low frequency shielding conductive structure is not less than 10 m.

10. The terminal of claim 9, wherein the low frequency shielding conductive structure is made of a conductive material with a conductivity not lower than 510.sup.6 S/m or a magnetic permeability greater than or equal to 410.sup.7/H/m.

11. The terminal of claim 9, wherein the area of the opening of each through hole in the region covering the electronic components that are configured to emit the low frequency electromagnetic waves in the low frequency shielding conductive structure is less than 1 mm*1 mm.

12. The terminal of claim 9, wherein the plurality of through holes of the low frequency shielding conductive structure are arranged in an array.

13. The terminal of claim 9, wherein the package body further comprises a conformal shielding layer arranged on an outer surface of the package material layer, wherein the conformal shielding layer is a nanoscale conductive metal layer, and wherein the low frequency shielding conductive structure is connected to the conformal shielding layer.

14. The terminal of claim 13, wherein the package body further comprises a complete conductive thin layer arranged between the low frequency shielding conductive structure and the conformal shielding layer.

15. The terminal of claim 9, wherein the package body further comprises a grounded conductive partition wall embedded in the package material layer, wherein the grounded conductive partition wall divides the package body into at least two compartments and is configured to weaken coupling of electromagnetic waves between different compartments.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic cross-sectional view in which a package body and a device sensitive to a low frequency electromagnetic wave are adjacent according to Embodiment 1 of this application.

(2) FIG. 2 is a schematic top view of a low frequency shielding conductive structure and a conductive partition wall in FIG. 1.

(3) FIG. 3 is a schematic diagram of several shapes of a low frequency shielding conductive structure.

(4) FIG. 4A and FIG. 4B are respectively a schematic top view and a schematic cross-sectional view of a package body according to an alternative embodiment.

(5) FIG. 5 is a schematic cross-sectional view of a package body according to Embodiment 2 of this application.

(6) FIG. 6 is a schematic cross-sectional view of a package body according to Embodiment 3 of this application.

(7) FIG. 7 is a schematic cross-sectional view of a package body according to Embodiment 4 of this application.

(8) FIG. 8A to FIG. 8D are schematic cross-sectional views of preparing a package body according to Embodiment 1.

LIST OF REFERENCE NUMERALS

(9) Package body 100, 200, 300, and 400 Substrate 10 Electronic component; 30 Package material layer 50 Device sensitive to a low frequency 60 electromagnetic wave Low frequency shielding conductive 20 structure Through hole 21 Relatively large through hole 25 Conformal shielding layer 70 Top surface 51 Side surface 53 Groove 55 Slot 57 Conductive partition wall 90 Conductive thin layer 40

DESCRIPTION OF EMBODIMENTS

(10) The following describes the embodiments of this application with reference to the accompanying drawings in the embodiments of this application.

Embodiment 1

(11) A terminal (not shown in the figure) includes: a housing (not shown in the figure) and a package body 100 located in the housing. The terminal may be an electronic device such as a mobile phone or a tablet computer.

(12) Referring to FIG. 1, the package body 100 includes a substrate 10, a plurality of electronic components 30 arranged on the substrate 10, and a package material layer 50 located on the substrate 10 and packaging the plurality of electronic components 30.

(13) The plurality of electronic components 30 may include one or more passive components. The passive components include, but are not limited to, a resistor, a capacitor, an inductor, a filter, a coupler, and the like. The plurality of electronic components 30 may further include one or more active components such as active chips. The active components include, but are not limited to, a power chip, a digital chip, a radio frequency chip, and the like. The active components and the passive components in the plurality of electronic components 30 include electronic components 30 emitting low frequency electromagnetic waves. In this application, the low frequency refers to a frequency less than 10 MHz, for example, greater than or equal to 10 kHz and less than 10 MHz. The package material layer 50 has a low dielectric constant and completely covers the plurality of electronic components 30.

(14) As shown in FIG. 1, a device 60 such as a near field communication (Near field communication, NFC) chip sensitive to a low frequency electromagnetic wave is disposed in the housing and beside the package body 100. However, an existing package body has a very limited shielding effect on a low frequency (which is generally under 10 MHz) electromagnetic wave, making surrounding devices 60 sensitive to the low frequency electromagnetic waves susceptible to interference. For example, in this embodiment, when the outside communicates with the NFC chip, low frequency noise in the low frequency electronic component 30 interferes with the NFC chip through an internal space of the package body 100 due to the proximity of the low frequency electronic component 30 and the NFC chip, resulting in reduction of the performance of NFC communication. Therefore, in this application, a low frequency shielding conductive structure 20 is arranged in the package body 100. The low frequency shielding conductive structure 20 can effectively shield the low frequency electromagnetic wave, thereby protecting the device 60 sensitive to the low frequency electromagnetic wave from interference of the low frequency electromagnetic wave.

(15) As shown in FIG. 1, the low frequency shielding conductive structure 20 is embedded in the package material layer 50, and the low frequency shielding conductive structure 20 is located on a side of the package material layer 50 away from the substrate 10 and is spaced apart from the plurality of electronic components 30. A surface of the low frequency shielding conductive structure 20 away from the substrate 10 is exposed relative to the package material layer 50. At least a part of the low frequency shielding conductive structure 20 is meshed, and the meshed part is provided with a plurality of through holes 21. Referring to FIG. 2, the entire low frequency shielding conductive structure 20 is meshed. The low frequency shielding conductive structure 20 is provided with a plurality of through holes 21. In this embodiment, the plurality of through holes 21 are arranged in a matrix, and an area of an opening of each through hole 21 is less than 1 mm*1 mm. A thickness of the low frequency shielding conductive structure 20 is not less than 10 m, for example, is greater than 10 m and less than or equal to 100 m. Because the low frequency shielding conductive structure 20 is embedded in the package material layer 50, each through hole 21 is filled with a package material of the package material layer 50.

(16) The low frequency shielding conductive structure 20 is made of a conductive material with a high conductivity (where the conductivity is not lower than 510.sup.6 S/m) or a high magnetic permeability (where the magnetic permeability is greater than or equal to 410.sup.7 H/m), for example, copper metal.

(17) The low frequency shielding principle of the low frequency shielding conductive structure 20 is described as follows: Wavelengths (30 m to 30000 m) of low frequency (10 kHz to 10 MHz) electromagnetic waves are relatively long, and the through holes 21 of the low frequency shielding conductive structure 20 are set relative small, so that the low frequency electromagnetic waves cannot penetrate a non-conductive region (a region of the through holes 21). In addition, in order to ensure the shielding effectiveness of the package for the low frequency (10 kHz to 10 MHz), it is necessary to increase a loss degree of the electromagnetic wave in the conductive structure.
Loss degree=attenuation factorthickness of conductive structure(1)
Attenuation factor=1/skin depth(2)
Skin depth=(2/(angular frequency*magnetic permeability*conductivity)).sup.0.5(3)

(18) Based on the formula (1), in addition to increasing the attenuation factor, the loss degree may be increased by increasing the thickness of the low frequency shielding conductive structure 20. Therefore, it is recommended that the thickness of the low frequency shielding conductive structure 20 be not less than 10 m.

(19) In addition, to increase the attenuation factor, that is, to decrease the skin depth, the conductive material with the high conductivity (where the conductivity is not lower than 510.sup.6 S/m) or the high magnetic permeability (where the magnetic permeability is greater than or equal to 410.sup.7 H/m) needs to be selected as the material of the low frequency shielding conductive structure 20.

(20) The low frequency shielding conductive structure 20 can greatly dissipate low frequency electromagnetic noise from the electronic component 30 below the low frequency shielding conductive structure, thereby significantly improving the shielding effectiveness of the package body 100 on electromagnetic radiation.

(21) The low frequency shielding conductive structure 20 does not necessarily cover a top region of the entire package body 100, and a region where the low frequency shielding conductive structure is arranged is related to a position of a low frequency noise source. The low frequency shielding conductive structure 20 needs to be arranged in a projection region of the low frequency electronic component and in a nearby region, to ensure that the low frequency electromagnetic wave emitted by the low frequency electronic component 30, after being transmitted over the package material layer 50, can be intercepted by the low frequency shielding conductive structure 20. The arrangement position of the low frequency shielding conductive structure 20 covers at least the low frequency electronic components 30, and a region covering the low frequency electronic components 30 is meshed, and an area of an opening of each through hole 21 in the meshed region is less than 1 mm*1 mm.

(22) As shown in FIG. 2, each through hole 21 of the low frequency shielding conductive structure 20 is a square, and the plurality of through holes 21 are arranged in an array. The shape of the through hole 21 is not limited and may be another shape. FIG. 3 shows the low frequency shielding conductive structure 20 in several different shapes. The shape of the through hole 21 may alternatively be a rectangle, a triangle, or another irregular shape.

(23) The plurality of through holes 21 may be arranged regularly and evenly, for example, array arrangement shown in FIG. 3. In another embodiment, as shown in FIG. 4A, the plurality of through holes 21 may alternatively be arranged unevenly. As shown in FIG. 4A, there is a relatively large through hole 25 (a blank region) in the plurality of through holes 21, and areas of the remaining through holes 21 are equal and are all less than 1 mm*1 mm. As shown in FIG. 4B, the relatively large through hole 25 directly faces one electronic component 30, the electronic component 30 has a height greater than heights of other electronic components 30 and is not the low frequency electronic component, and an area of the relatively large through hole 25 is greater than a cross section of the electronic component 30 for the electronic component 30 to run through the relatively large through hole 25. That is, the region directly facing the electronic component 30 is not provided with the meshed part of the low frequency shielding conductive structure 20, but is blank. In this way, even if the height of the electronic component 30 in a local region of the package body 100 is relatively high, an overall height of the package body 100 does not increase due to the introduction of the low frequency shielding conductive structure 20.

(24) As shown in FIG. 1, a conformal shielding layer 70 is further arranged on an outer surface of the package material layer 50, and the low frequency shielding conductive structure 20 is in direct contact with and connected to the conformal shielding layer 70. The package material layer 50 includes a top surface 51 away from the substrate 10 and a plurality of side surfaces 53 connected to the top surface 51. The conformal shielding layer 70 completely covers the top surface 51 and the plurality of side surfaces 53 and extends along the side surfaces 53 to cover a surface where the substrate 10 is coplanar with the side surface 53. The conformal shielding layer 70 is a nanoscale conductive metal layer and is generally a conductive metal layer with a thickness not greater than 10 micrometers. The conformal shielding layer 70 is mainly configured to shield high frequency (which is generally greater than 10 MHz) electromagnetic waves.

(25) As shown in FIG. 1, the low frequency shielding conductive structure 20 is flush with the top surface 51 of the package material layer 50, so that the low frequency shielding conductive structure 20 and the conformal shielding layer 70 can be better connected.

(26) The surface of the low frequency shielding conductive structure 20 away from the substrate 10 is in contact with the conformal shielding layer 70. The low frequency shielding conductive structure 20 may further extend to an edge of the package body 100 and is in contact with a part of the conformal shielding layer 70 covering the side surfaces 53, or may not extend to an edge of the package body 100 and is not in contact with a part of the conformal shielding layer 70 covering the side surfaces 53.

(27) In addition, a compartment shielding (compartment shielding) technology is used to ensure that the electronic components 30 inside the package body 100 do not interfere with each other. As shown in FIG. 1, a grounded conductive partition wall 90 may further be embedded in the package material layer 50, to divide the package body 100 into at least two compartments, so that coupling of electromagnetic waves between the compartments is greatly weakened, thereby implementing shielding between the internal electronic components 30 of the package body 100. One end of the conductive partition wall 90 is connected to the conformal shielding layer 70, and an other end of the conductive partition wall is connected to the substrate 10.

(28) A simulation test of shielding effectiveness is performed for two groups of Experimental Examples 1-2 and two groups of Comparative Examples 1-2 of this application below, and test results are shown in Table 1 below. In Comparative Example 1, the conformal shielding layer 70 has a thickness of 3 m, in Experimental Example 1, in addition to the conformal shielding layer 70 with the thickness of 3 m, the low frequency shielding conductive structure 20 is arranged (a thickness is 50 m, and the through hole 21 is a square with a side length of 0.5 mm), and another condition of Comparative Example 1 is the same as that of Experimental Example 1. In Comparative Example 2, the conformal shielding layer 70 has a thickness of 9 m, in Experimental Example 2, in addition to the conformal shielding layer 70 with the thickness of 9 m, the low frequency shielding conductive structure 20 is arranged (a thickness is 50 m, and the through hole 21 is a square with a side length of 0.5 mm), and another condition of Comparative Example 2 is the same as that of Experimental Example 2.

(29) TABLE-US-00001 TABLE 1 Frequencies of Comparative Experimental Comparative Experimental electromagnetic Example 1 Example 1 Example 2 Example 2 waves Shielding effectiveness 100 KHz 0.7 dB 4.6 dB 2 dB 5.2 dB 1 MHz 2 dB 15.5 dB 5.5 dB 18 dB 10 MHz 13 dB 30 dB 24 dB 34 dB

(30) It can be learned from Table 1 that at a frequency of 1 MHz, the shielding effectiveness of the conformal shielding layer with the thickness of 3 m is only 2 dB, while the shielding effectiveness of the conformal shielding layer with the thickness of 9 m is only 5.5 dB. The shielding effectiveness can be increased by 12.5 dB and 13.5 dB respectively after the low frequency shielding conductive structure is added. At a frequency of 10 MHz, the shielding effectiveness of the conformal shielding layer with the thickness of 3 m is only 13 dB, while the shielding effectiveness of the conformal shielding layer with the thickness of 9 m is only 24 dB. The shielding effectiveness can be increased by 17 dB and 10 dB respectively after the low frequency shielding conductive structure is added.

(31) In this embodiment, the low frequency shielding conductive structure 20 that is provided with the plurality of through holes 21 is arranged on the top of the package body 100 and is connected to the conformal shielding layer 70, to greatly improve the shielding effectiveness on low frequency electromagnetic radiation. In addition, the low frequency shielding conductive structure 20 can further assist in increasing the shielding effectiveness on high frequency electromagnetic radiation to some extent.

Embodiment 2

(32) Referring to FIG. 5, a package body 200 of Embodiment 2 of this application is substantially consistent with the structure of the package body 100 of Embodiment 1, and a difference lies in that in the package body 200 of this embodiment, a complete conductive thin layer 40 is further arranged between the low frequency shielding conductive structure 20 and the conformal shielding layer 70.

(33) The conductive thin layer 40 is embedded in the package material layer 50. The conductive thin layer 40 may have any thickness. The conformal shielding layer 70 is on the conductive thin layer 40. In this way, the shielding effectiveness can further be improved, and a preparation method of the package body 200 may be simpler than that of Embodiment 1, for example, mechanical grinding on the low frequency shielding conductive structure 20 with the through holes 21 and the package material layer 50 is not required.

(34) Compared with Embodiment 1, in the package body 200 of this embodiment, the complete conductive thin layer 40 is added, and the presence of the conductive thin layer 40 can further dissipate upward propagated electromagnetic waves, thereby further improving the low frequency electromagnetic shielding effectiveness of the package body 100.

Embodiment 3

(35) Referring to FIG. 6, a package body 300 of Embodiment 3 of this application is substantially consistent with the structure of the package body 100 of Embodiment 1, and a difference lies in that in the package body 300 of this embodiment, the conformal shielding layer 70 and the conductive partition wall 90 are not arranged.

(36) In this way, the costs of process and material caused by arranging the conformal shielding layer can be saved, and the low frequency shielding performance of the package body 100 can also be ensured. However, the high frequency shielding performance of the package body 300 is worse than that of the package body 100 provided with the conformal shielding layer 70, but for the package body 300 with only the low frequency electronic components 30 inside, only the low frequency shielding conductive structure 20 is arranged without considering the high frequency shielding performance.

Embodiment 4

(37) Referring to FIG. 7, a package body 400 of Embodiment 4 of this application is substantially consistent with the structure of the package body 200 of Embodiment 2, and a difference lies in that in the package body 400 of this embodiment, the conformal shielding layer 70 and the conductive partition wall 90 are not arranged.

(38) The package body 400 of Embodiment 4 satisfies shielding requirements of the package requiring only low frequency shielding, and reduces the complexity and difficulty of process implementation.

(39) This application further provides an electronic device (not shown in the figure), including at least one package body in Embodiment 1 to Embodiment 4

(40) Referring to FIG. 8, this application further provides a preparation method of the package body, including the following steps.

(41) S1: As shown in FIG. 8A, provide an initial package body, where the initial package body includes a substrate 10, a plurality of electronic components 30 arranged on the substrate 10, and a package material layer 50 located on the substrate and packaging the plurality of electronic components 30.

(42) The plurality of electronic components 30 may include one or more passive components and may further include one or more active components. The active components and the passive components in the plurality of electronic components 30 include low frequency electronic components 30. In this application, a range of the low frequency is less than 10 MHz, for example, is greater than or equal to 10 kHz and less than 10 MHz. The package material layer 50 has a low dielectric constant and the package material layer 50 completely covers the plurality of electronic components 30.

(43) S2: As shown in FIG. 8A, provide a groove 55 on a side of the package material layer 50 away from the substrate 10, where at least a part of the groove 55 is meshed.

(44) The groove 55 may be formed by laser grooving, but is not limited to laser grooving. A thickness of the groove 55 is not less than 10 m, for example, is greater than 10 m and less than or equal to 100 m. The groove 55 does not run through the package material layer 50 and is spaced apart from the plurality of electronic components 30. The package material layer 50 is provided with a region of the meshed part of the groove 55, the region is divided by the groove 55 into a plurality of spaced units (not shown in the figure), and an area of each unit is less than 1 mm*1 mm. It may be understood that a slot 57 running through the package material layer 50 may further be formed together with the groove 55, and the slot 57 is configured to accommodate the conductive partition wall 90 subsequently.

(45) S3: As shown in FIG. 8B, form a conductive material in the groove 55, to form a low frequency shielding conductive structure 20.

(46) The low frequency shielding conductive structure 20 may be formed by pouring conductive paste into the groove 55 and then thermal curing. It may be understood that the conductive paste may also be poured into the slot 57 and cured to form the conductive partition wall 90.

(47) After curing, as shown in FIG. 8C, the low frequency shielding conductive structure 20 and the package material layer 50 may also be ground, so that the low frequency shielding conductive structure and the package material layer are away from a surface of the substrate 10 and are flush with the surface of the substrate.

(48) S4: As shown in FIG. 8D, form a conformal shielding layer 70 on an outer surface of the package material layer 50, where the conformal shielding layer 70 is in contact with the low frequency shielding conductive structure 20.

(49) The conformal shielding layer 70 is also in contact with the conductive partition wall 90. The conformal shielding layer 70 may be formed by a process such as sputtering or spraying to form a nanoscale conductive metal layer and is generally a conductive metal layer with a thickness of not greater than 10 micrometers. Step S4 may also be omitted as required.

(50) It may be understood that the method may further include: forming a conductive thin layer on a surface of the low frequency shielding conductive structure 20 away from the substrate 10 before forming the conformal shielding layer 70. For example, an accommodating groove (not shown in the figure) for accommodating the conductive thin layer may be provided when the groove 55 is provided on the package material layer 50, and then conductive materials are formed together in the groove 55 and the accommodating groove to form the low frequency shielding conductive structure 20 and the conductive thin layer.

(51) It should be noted that, the foregoing is merely a specific implementation of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. The implementations in this application and features in the implementations may be combined with each other in the case of no conflict. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.