CN117334582A - Selective packaging method, packaging structure and radio frequency module - Google Patents

Selective packaging method, packaging structure and radio frequency module Download PDF

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Publication number
CN117334582A
CN117334582A CN202311281493.6A CN202311281493A CN117334582A CN 117334582 A CN117334582 A CN 117334582A CN 202311281493 A CN202311281493 A CN 202311281493A CN 117334582 A CN117334582 A CN 117334582A
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CN
China
Prior art keywords
substrate
radio frequency
frequency device
layer
cavity
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202311281493.6A
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Chinese (zh)
Inventor
姜伟
高安明
郑磊
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Zhejiang Xingyao Semiconductor Co ltd
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Zhejiang Xingyao Semiconductor Co ltd
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Application filed by Zhejiang Xingyao Semiconductor Co ltd filed Critical Zhejiang Xingyao Semiconductor Co ltd
Priority to CN202311281493.6A priority Critical patent/CN117334582A/en
Publication of CN117334582A publication Critical patent/CN117334582A/en
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/05—Holders; Supports
    • H03H9/10—Mounting in enclosures
    • H03H9/1064—Mounting in enclosures for surface acoustic wave [SAW] devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
    • H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/31—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape
    • H01L23/3107—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape the device being completely enclosed
    • H01L23/315—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape the device being completely enclosed the encapsulation having a cavity
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/16—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits

Abstract

The application discloses a selective packaging method, a packaging structure and a radio frequency module comprising the packaging structure, wherein a blocking layer is formed in a preset area on the surface of a substrate, so that when a first radio frequency device needing to be underfilled and a second radio frequency device incapable of being underfilled are welded on the surface of the substrate, the blocking layer surrounds a cavity between a functional area of the second radio frequency device and the surface of the substrate, the blocking layer is attached to the surface of the second radio frequency device facing the substrate, so that a plastic package material is blocked by the blocking layer to enter the cavity between the functional area of the second radio frequency device and the surface of the substrate, and meanwhile, the blocking layer exposes a gap between the first radio frequency device and the surface of the substrate, so that the plastic package material can fill the gap between the first radio frequency device and the surface of the substrate, namely, the underfilling of the first radio frequency device is realized, and the cavity between the functional area of the second radio frequency device and the surface of the substrate is reserved.

Description

Selective packaging method, packaging structure and radio frequency module
Technical Field
The present disclosure relates to the field of radio frequency technologies, and in particular, to a selective packaging method, a packaging structure obtained by applying the selective packaging method, and a radio frequency module including the packaging structure.
Background
The radio frequency module is a solution that two or more than two discrete devices of a filter, a radio frequency switch, a low noise amplifier, a power amplifier, a duplexer and a multiplexer are integrated in the same module, so that the integration level of the radio frequency chip can be improved, and the radio frequency chip is further miniaturized.
In the current market environment, the trend of radio frequency modularity of mobile phones is quite obvious. Although in early ages of 3G and 4G, the frequency range to be covered by the mobile phone is not large, and the rf front end often adopts a discrete design scheme, so that in the era of multi-frequency and multi-mode, especially after the 5G is gradually commercialized and popularized, the mobile phone needs a very large number of devices to meet the support requirement of the global frequency range, the rf front end becomes more complex, and the trend of modularity, integration and miniaturization begins to occur naturally due to the limited design space of the mobile phone motherboard. The increasingly tense contradiction between the continuously increased number of radio frequency front-end devices and the available area of the PCB promotes the gradual development of radio frequency front-end module products with high integration level.
The packaging of the radio frequency module product is an important ring in the process, and can package the radio frequency module chip in a protective material, so that the radio frequency module chip is not influenced by external environment, and better electromagnetic compatibility, thermal management and mechanical protection are provided. The radio frequency chip is easy to be influenced by electrostatic breakdown, mechanical vibration, humidity and the like in the operation process, and the stability and the reliability of the chip can be improved by the physical barrier provided by the package; meanwhile, electromagnetic shielding and isolation can absorb external electromagnetic interference, reduce internal electromagnetic coupling and interference, and provide heat dissipation paths and protection against physical vibration, impact and the like for the chip.
For rf module products, an important technology in the packaging process is that for flip chips, some chips (e.g. rf switches, etc.) need to be underfilled to provide better protection and stability, while some chips (e.g. SAW filters, etc.) cannot be underfilled, and air cavities need to be reserved for functional areas, which makes an optional underfilling process during product packaging.
How to provide a safe and reliable selective packaging scheme for simultaneously packaging a radio frequency device requiring underfill and a radio frequency device incapable of being underfilled is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
In order to solve the above technical problems, the embodiments of the present application provide a selective packaging method, a packaging structure obtained by applying the selective packaging method, and a radio frequency module including the packaging structure, so as to provide a safe and reliable selective packaging scheme for simultaneously packaging a radio frequency device that needs to be underfilled and a radio frequency device that cannot be underfilled.
In order to achieve the above purpose, the embodiment of the present application provides the following technical solutions:
A method of selective encapsulation comprising:
providing a substrate, wherein the surface of the substrate is provided with a plurality of bonding pads;
forming a barrier layer in a preset area on the surface of the substrate;
the welding radio frequency device comprises a first radio frequency device and a second radio frequency device, wherein the salient point of the first radio frequency device is correspondingly welded with part of the bonding pad, and the salient point of the second radio frequency device is correspondingly welded with the other part of the bonding pad; the second radio frequency device is provided with a functional area, a cavity is arranged between the functional area and the surface of the substrate, the blocking layer surrounds the cavity, the blocking layer is attached to the surface of the second radio frequency device, which faces the substrate, and the blocking layer exposes a gap between the first radio frequency device and the surface of the substrate;
filling a plastic package material, so that the plastic package material fills a gap between the first radio frequency device and the surface of the substrate and covers the first radio frequency device, the second radio frequency device, the barrier layer and the surface of the substrate.
Optionally, forming the barrier layer in the preset area of the surface of the substrate includes:
and forming at least one layer of solder mask layer serving as the barrier layer in a preset area on the surface of the substrate.
Optionally, forming the barrier layer in the preset area of the surface of the substrate includes:
covering a layer of dry film on the surface of the substrate;
and etching the dry film, removing the dry film outside the preset area on the surface of the substrate, and taking the dry film in the preset area on the surface of the substrate as the barrier layer.
Optionally, in the process of preparing the second radio frequency device, forming at least one circle of metal layer surrounding the functional area on the surface of the second radio frequency device, wherein one circle of metal layer comprises a plurality of metal segments which are arranged at intervals;
when the radio frequency device is welded, the blocking layer is attached to the surface of the second radio frequency device, which faces the substrate, and the blocking layer comprises:
the barrier layer is attached to the surface of the metal layer facing the substrate.
A package structure, comprising:
a substrate, the surface of which is provided with a plurality of bonding pads;
the barrier layer is positioned in a preset area on the surface of the substrate;
the radio frequency device comprises a first radio frequency device and a second radio frequency device, wherein the salient point of the first radio frequency device is correspondingly welded with part of the bonding pad, and the salient point of the second radio frequency device is correspondingly welded with the other part of the bonding pad; the second radio frequency device is provided with a functional area, a cavity is arranged between the functional area and the surface of the substrate, the blocking layer surrounds the cavity, the blocking layer is attached to the surface of the second radio frequency device, which faces the substrate, and the blocking layer exposes a gap between the first radio frequency device and the surface of the substrate;
And the plastic packaging material fills the gap between the first radio frequency device and the surface of the substrate and covers the first radio frequency device, the second radio frequency device, the barrier layer and the surface of the substrate.
Optionally, the bump of the second radio frequency device is located at the outer side of the cavity, and the blocking layer includes a first blocking portion, where the first blocking portion is located at a side of the bump of the second radio frequency device, where the bump is away from the cavity.
Optionally, the bump of the second radio frequency device is located at the outer side of the cavity, and the blocking layer includes a second blocking portion, where the second blocking portion is located at a side of the bump of the second radio frequency device, where the bump is close to the cavity.
Optionally, the bump of the second radio frequency device is located at the outer side of the cavity, the blocking layer includes a first blocking portion and a second blocking portion, at least one of the first blocking portion and the second blocking portion is attached to the surface of the second radio frequency device facing the substrate, the first blocking portion is located at a side, away from the cavity, of the bump of the second radio frequency device, and the second blocking portion is located at a side, close to the cavity, of the bump of the second radio frequency device.
Optionally, the second blocking part is attached to the surface of the second radio frequency device facing the substrate, and the thickness of the first blocking part is smaller than that of the second blocking part;
the plastic packaging material is also filled in a gap between the second radio frequency device and the surface of the substrate, and is positioned at one side of the second blocking part, which is away from the cavity.
Optionally, the orthographic projection of the blocking layer on the surface of the substrate is located outside the orthographic projection of the first radio frequency device on the surface of the substrate.
Optionally, the distance between the surface of the first rf device facing the substrate and the substrate surface is greater than the distance between the surface of the second rf device facing the substrate and the substrate surface.
Optionally, the barrier layer is a single-layer structure, or the barrier layer is at least two layers stacked along a direction away from the surface of the substrate.
Optionally, the surface of the second radio frequency device facing the substrate has at least one circle of metal layer surrounding the functional area, and one circle of metal layer comprises a plurality of metal segments arranged at intervals;
the barrier layer is attached to the surface of the metal layer facing the substrate.
Optionally, the at least one circle of metal layer includes a first circle of metal layer and a second circle of metal layer located on one side of the first circle of metal layer, which is away from the functional area, the metal segments in the first circle of metal layer correspond to gaps between two adjacent metal segments in the second circle of metal layer, and the metal segments in the second circle of metal layer correspond to gaps between two adjacent metal segments in the first circle of metal layer.
A radio frequency module comprising a package structure obtained by the selective packaging method described in any one of the above, or comprising the package structure described in any one of the above.
Compared with the prior art, the technical scheme has the following advantages:
according to the selective packaging method and the packaging structure, the barrier layer is formed in the preset area of the substrate surface, so that when the radio frequency device is welded on the substrate surface, the bump of the first radio frequency device is welded with the partial bonding pad of the substrate surface, the bump of the second radio frequency device is welded with the other partial bonding pad of the substrate surface, the barrier layer surrounds the cavity between the functional area of the second radio frequency device and the substrate surface, the barrier layer is attached to the surface of the second radio frequency device facing the substrate, and then when the plastic packaging material is filled, the barrier layer can block the plastic packaging material from entering the cavity between the functional area of the second radio frequency device and the substrate surface, and meanwhile, the barrier layer exposes the gap between the first radio frequency device and the substrate surface. Compared with the existing packaging method adopting laser film removal and then selective underfilling, the selective packaging method provided by the embodiment of the application has the advantages that a radio frequency device is not damaged, the safety and the reliability are realized, the process is simple, and the cost is low.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIGS. 1 a-1 e are schematic diagrams illustrating the structure of a conventional selective packaging method corresponding to each process step;
fig. 2 is a flow chart of a selective encapsulation method according to an embodiment of the present application;
fig. 3a to 3d are schematic structural diagrams corresponding to each process step in a selective packaging method according to an embodiment of the present application;
FIG. 3e is a bottom view of the package structure shown in FIG. 3d along the surface of the substrate;
fig. 4a is a schematic diagram of a package structure according to an embodiment of the present application;
FIG. 4b is a bottom view of the package structure of FIG. 4a along the surface of the substrate;
fig. 5a to 5d are schematic structural diagrams corresponding to each process step in another alternative packaging method according to the embodiments of the present application;
FIG. 5e is a bottom view of the package structure of FIG. 5d along the surface of the substrate;
fig. 6a to 6e are schematic structural diagrams corresponding to each process step in another alternative packaging method according to an embodiment of the present application;
FIG. 6f is a bottom view of the package structure of FIG. 6e along the surface of the substrate;
fig. 7a to fig. 7d are schematic structural diagrams corresponding to each process step in another alternative packaging method according to an embodiment of the present application;
FIG. 7e is a bottom view of the package structure of FIG. 7d along the surface of the substrate;
fig. 8 is a schematic bottom view of another package structure along a surface of a substrate according to an embodiment of the present disclosure;
FIG. 9 is a schematic bottom view of another package structure along a surface of a substrate according to an embodiment of the present disclosure;
FIG. 10a is a schematic diagram of another package structure according to an embodiment of the present disclosure;
FIG. 10b is a bottom view of the package structure of FIG. 10a along the surface of the substrate;
FIG. 11 is a schematic diagram of another package structure according to an embodiment of the present disclosure;
FIG. 12 is a schematic view of another package structure according to an embodiment of the present disclosure;
fig. 13a to 13d are schematic structural diagrams corresponding to each process step in another alternative packaging method according to the embodiments of the present application;
FIG. 13e is a bottom view of the package structure of FIG. 13d along the surface of the substrate;
FIG. 14a is a schematic view of another package structure according to an embodiment of the present disclosure;
fig. 14b is a bottom view of the package structure shown in fig. 14 a.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present application is not limited to the specific embodiments disclosed below.
Next, the present application will be described in detail with reference to the schematic drawings, wherein the cross-sectional views of the device structure are not to scale for the sake of illustration, and the schematic drawings are merely examples, which should not limit the scope of protection of the present application. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
As described in the background section, how to provide a safe and reliable alternative packaging scheme for simultaneously packaging a radio frequency device requiring underfill and a radio frequency device incapable of being underfilled is a technical problem to be solved by those skilled in the art.
In the prior art, the film is often coated on the surface of the welded radio frequency device, and then the film breaking or removing operation is performed on the corresponding area of the radio frequency device needing to be subjected to bottom filling, so that the bottom area of the radio frequency device can be covered when the plastic packaging material is filled.
Specifically, as shown in fig. 1 a-1 e, fig. 1a shows a schematic cross-sectional view of a rf module product, and an rf device 02 that needs to be underfilled, an rf device 03 that cannot be underfilled, and other rf devices 04 are sequentially soldered on a substrate 01 from left to right; in the existing selective underfill solution, first, as shown in fig. 1b, a layer of film 05 (commonly used plastic packaging film) is covered on the surface of the rf device and the surface of the substrate; then, as shown in fig. 1c, performing a membrane breaking operation at a position (specifically, a position indicated by an arrow in the figure) corresponding to the bottom of the radio frequency device 02 to be underfilled, to obtain a structure shown in fig. 1 d; then, as shown in fig. 1e, the plastic package material 06 is refilled to obtain a selectively underfilled package structure, so that the plastic package material 06 fills the bottom of the radio frequency device 02 while the bottom of the radio frequency device 03 is not filled with the plastic package material 06, thereby providing better physical protection for the radio frequency device 02 and improving the stability of the package structure.
In the prior art, a laser film removing method is often adopted when the film is broken, specifically, a laser etching method is adopted to remove the surface film at a designated position, and the method has the advantages of convenience in operation and higher control precision; however, the defects are also more remarkable, the cost is higher, and the process complexity is greatly increased on the premise of gradually improving the device integration level, the film removal failure possibly caused by the change of various conditions can be caused, and the damage of the radio frequency device can be possibly caused.
In view of this, the embodiment of the present application provides a selective packaging method and a packaging structure obtained by using the selective packaging method, and fig. 2 shows a flow chart of the selective packaging method provided by the embodiment of the present application, as shown in fig. 2, the selective packaging method includes:
s110: providing a substrate, wherein the surface of the substrate is provided with a plurality of bonding pads;
s120: forming a barrier layer in a preset area on the surface of the substrate;
s130: the welding radio frequency device comprises a first radio frequency device and a second radio frequency device, wherein the salient point of the first radio frequency device is correspondingly welded with one part of the bonding pad, and the salient point of the second radio frequency device is correspondingly welded with the other part of the bonding pad; the second radio frequency device is provided with a functional area, a cavity is arranged between the functional area and the surface of the substrate, the barrier layer surrounds the cavity, the barrier layer is attached to the surface of the second radio frequency device facing the substrate, and the barrier layer exposes a gap between the first radio frequency device and the surface of the substrate;
S140: filling a plastic package material, so that the plastic package material fills a gap between the first radio frequency device and the surface of the substrate and covers the first radio frequency device, the second radio frequency device, the barrier layer and the surface of the substrate.
The first radio frequency device is a radio frequency device needing to be subjected to bottom filling, for example, the first radio frequency device is a radio frequency switch; the second rf device is an rf device that cannot be underfilled, specifically, a cavity between a functional area of the second rf device and a surface of the substrate cannot be filled, for example, the second rf device is a surface acoustic wave device, the surface acoustic wave device includes a piezoelectric layer and an input/output interdigital electrode located on the piezoelectric layer, and when the second rf device specifically works, an electrical signal is converted into an acoustic signal by the input interdigital electrode, the acoustic signal propagates along the surface of the piezoelectric layer, and then the received acoustic signal is converted into an electrical signal by the output interdigital electrode to be output.
According to the selective packaging method and the packaging structure, the barrier layer is formed in the preset area of the surface of the substrate, so that when the radio frequency device is welded on the surface of the substrate, the barrier layer surrounds the cavity between the functional area of the second radio frequency device and the surface of the substrate, and the barrier layer is attached to the surface of the second radio frequency device facing the substrate. Compared with the existing packaging method adopting laser film removal and then selective underfilling, the selective packaging method provided by the embodiment of the application has the advantages that a radio frequency device is not damaged, the safety and the reliability are realized, the process is simple, and the cost is low.
In this embodiment of the present invention, the preset area of the substrate surface includes at least a peripheral area of the substrate surface corresponding to the functional area of the second radio frequency device, but does not include the substrate surface area corresponding to the functional area, so that the barrier layer may enclose the cavity between the functional area and the substrate surface, and the barrier layer is attached to the surface of the second radio frequency device facing the substrate, so that the barrier layer may block the molding material from entering the cavity.
It should be noted that the position, shape and volume of the barrier layer located between the surface of the second rf device facing the substrate and the surface of the substrate are not limited in this application, as long as the portion of the barrier layer surrounds the cavity and can block the molding compound from entering the cavity.
In this embodiment of the present application, the barrier layer exposes a gap between the first radio frequency device and the surface of the substrate, which may be that the thickness of the barrier layer is smaller than the distance between the surface of the first radio frequency device facing the substrate and the surface of the substrate, or may be that the orthographic projection of the barrier layer on the surface of the substrate is located outside the orthographic projection of the first radio frequency device on the surface of the substrate, as long as the barrier layer allows the molding material to fill the gap between the first radio frequency device and the substrate.
Optionally, in some embodiments, forming the barrier layer in the predetermined area of the substrate surface in step S120 includes:
s121: at least one solder mask layer is formed as a barrier layer in a predetermined area of the substrate surface.
Specifically, fig. 3a to 3d show schematic structural diagrams corresponding to each process step in a selective packaging method for forming a solder mask layer as a barrier layer on a preset area of a surface of a substrate, where the selective packaging method includes:
s210: as shown in fig. 3a, a substrate 10 is provided, and the substrate surface has a plurality of pads 11, i.e., a plurality of pads 11 are formed on the substrate surface in advance.
S220: as shown in fig. 3b, a solder mask layer 21 is formed as a barrier layer 20 on a predetermined area of the substrate surface.
Wherein a heat-curable solder resist material (e.g., green oil) may be used, and the solder resist layer 21 is formed by curing the heat-curable solder resist material by heating; the solder resist layer 21 may also be formed by using a photoresist material and curing the photoresist material by exposure and development.
S230: as shown in fig. 3c, the radio frequency device 30 is soldered, the radio frequency device 30 includes a first radio frequency device 31 and a second radio frequency device 32, wherein the first radio frequency device 31 is a radio frequency device that needs to be underfilled, the second radio frequency device 32 is a radio frequency device that cannot be underfilled, the second radio frequency device 32 has a functional region 321, a cavity K1 is provided between the functional region 321 and a surface of the substrate, the barrier layer 20 surrounds the cavity K1, and the barrier layer 20 is attached to the surface of the second radio frequency device 32 facing the substrate 10, while the barrier layer 20 exposes a gap between the first radio frequency device 31 and the surface of the substrate.
Specifically, when the rf devices are soldered, the bump 311 of the first rf device 31 is soldered to a portion of the pad 11, and the bump 322 of the second rf device 32 is soldered to another portion of the pad 11. As shown in fig. 3c, the rf device 30 may also include other rf devices 33.
In this embodiment, the thickness d1 of the barrier layer 20 may be just equal to or slightly greater than the distance d2 between the surface of the second rf device 32 facing the substrate 10 and the substrate surface, where a range where d1 is slightly greater than d2 refers to a range where the barrier layer 20 and the surface of the second rf device 32 facing the substrate 10 can be ensured to be tightly adhered under the condition of micro deformation without causing physical damage to the second rf device 32.
In this embodiment, by setting the height of the bump 311 of the first rf device 31 and the height of the bump 322 of the second rf device 32 so that the distance d3 between the surface of the first rf device 31 facing the substrate 10 and the substrate surface is greater than the distance d2 between the surface of the second rf device 32 facing the substrate 10 and the substrate surface, the gap between the first rf device 31 and the substrate surface may be exposed while the barrier layer 20 and the surface of the second rf device 32 are attached to each other, and at this time, the front projection of the barrier layer 20 on the substrate surface may overlap with the front projection of the first rf device 31 on the substrate surface, or may not overlap with each other, and even if the front projection of the barrier layer 20 on the substrate surface overlaps with the front projection of the first rf device 31 on the substrate surface, the barrier layer 20 may still expose the gap between the first rf device 31 and the substrate surface, so that the gap between the first rf device 31 and the substrate 10 may be filled with the molding material when the molding material is subsequently performed.
S240: as shown in fig. 3d, the molding material 40 is filled, so that the molding material 40 fills the gap between the first rf device 31 and the substrate 10 and covers the first rf device 31, the second rf device 32, the barrier layer 20, and the substrate surface.
In the package structure shown in fig. 3d, since the barrier layer 20 surrounds the cavity K1 and the barrier layer 20 is attached to the surface of the second rf device 32 facing the substrate 10, the barrier layer 20 can block the plastic package material 40 from entering the cavity K1 between the functional area 321 of the second rf device 32 and the substrate surface.
Fig. 3e further shows a schematic bottom view of the package structure shown in fig. 3d along the surface of the substrate, wherein the dashed box corresponds to the cavity K1, that is, corresponds to the functional region 321 of the second rf device 32, and it can be seen that, in this embodiment, the bump 322 of the second rf device 32 is located outside the cavity K1, and the barrier layer 20 is located on a side of the bump 322 of the second rf device 32 facing away from the cavity K1.
Further optionally, as shown by the dashed rectangle in fig. 4a and 4b, the front projection of the blocking layer 20 on the substrate surface may be located outside the front projection of the first rf device 31 on the substrate surface, i.e. in the direction perpendicular to the substrate surface, where the blocking layer 20 and the first rf device 31 are not overlapped, so that a larger opening is reserved for filling the gap between the first rf device 31 and the substrate surface with the molding compound 40.
Fig. 5 a-5 d are schematic structural views showing the respective process steps in a selective packaging method for forming two solder masks as barrier layers on a predetermined area of a surface of a substrate, where the selective packaging method includes:
s310: as shown in fig. 5a, a substrate 10 is provided, and the substrate surface has a plurality of pads 11, i.e., a plurality of pads 11 are formed on the substrate surface in advance.
S320: as shown in fig. 5b, the first solder mask 22 is formed in a preset area of the substrate surface, and the thickness of the first solder mask 32 is smaller than the distance between the surface of the first rf device 31 facing the substrate 10 and the substrate surface, and smaller than the distance between the surface of the second rf device 32 facing the substrate 10 and the substrate surface; then, as shown in fig. 5c, a second solder resist layer 23 is formed on the surface of the first solder resist layer 22 facing away from the substrate 10, and the first solder resist layer 22 and the second solder resist layer 23 integrally constitute the barrier layer 20.
S330: as shown in fig. 5c, the radio frequency device 30, i.e. the first 31 and the second 32 radio frequency device, and the other radio frequency device 33 are soldered.
Optionally, after the first solder mask layer 22 and the second solder mask layer 23 are formed, the second radio frequency device 32 can be welded under the condition that the solder mask material is not completely cured, and then the two layers of solder mask layers are thoroughly cured, so that on one hand, the first solder mask layer 22 and the second solder mask layer 23 are tightly attached to form a whole to form the solder mask layer as the barrier layer 20, the subsequent plastic package material is ensured not to enter the cavity K1, and on the other hand, the chip damage caused by external stress when the deviation between the whole thickness of the first solder mask layer 22 and the second solder mask layer 23 and the height dimension of the cavity K1 is larger can be reduced.
S340: as shown in fig. 5d, the molding material 40 is filled, so that the molding material 40 fills the gap between the first rf device 41 and the substrate surface and covers the first rf device 31, the second rf device 32, the barrier layer 20, and the substrate surface.
In this embodiment, the second solder mask layer 23 may be only located in the area of the first solder mask layer 22 corresponding to the second rf device 32, as shown in fig. 5d, or may extend to a part of the area of the first solder mask layer 22 not corresponding to the second rf device 32.
In the present embodiment, since the thickness of the first solder resist layer 22 is smaller than the distance between the surface of the first rf device 31 facing the substrate 10 and the substrate surface, if the second solder resist layer 23 and the first rf device 31 do not overlap in the direction perpendicular to the substrate surface, the barrier layer 20 integrally formed of the first solder resist layer 22 and the second solder resist layer 23 exposes the gap between the first rf device 31 and the substrate surface, enabling the molding material 40 to fill the gap between the first rf device 31 and the substrate 10; if both the first and second solder masks 22 and 23 intersect the first rf device 31 in a direction perpendicular to the substrate surface, the overall thickness of the first and second solder masks 22 and 23 may be set smaller than the distance between the surface of the first rf device 31 facing the substrate 10 and the substrate surface, so that the barrier layer 20 integrally formed of the first and second solder masks 22 and 23 exposes the gap between the first rf device 31 and the substrate surface, enabling the molding material 40 to fill the gap between the first rf device 31 and the substrate 10.
Fig. 5e further illustrates a schematic bottom view of the package structure shown in fig. 5d along the surface of the substrate, wherein the dashed box corresponds to the cavity K1, that is, corresponds to the functional region 321 of the second rf device 32, and it can be seen that, in this embodiment, the bump 322 of the second rf device 32 is located outside the cavity K1, and the barrier layer 20 is located on a side of the bump 322 of the second rf device 32 facing away from the cavity K1.
The above-described embodiments exemplify the case where one solder resist layer is formed as a barrier layer and two solder resist layers are formed as barrier layers in predetermined areas of the substrate surface. It will be appreciated that three or more solder masks may also be formed as barrier layers in predetermined areas of the substrate surface, as the case may be.
Optionally, in some embodiments, forming the barrier layer in the predetermined area of the substrate surface in step S120 includes:
s122: and covering a layer of dry film on the surface of the substrate.
S123: and etching the dry film, removing the dry film outside the preset area on the surface of the substrate, and taking the dry film in the preset area on the surface of the substrate as a barrier layer.
Specifically, fig. 6a to 6e show schematic structural diagrams corresponding to each process step in a selective packaging method for covering a dry film on a surface of a substrate and etching the dry film to form a barrier layer, where the selective packaging method includes:
S410: as shown in fig. 6a, a substrate 10 is provided, and the substrate surface has a plurality of pads 11, i.e., a plurality of pads 11 are formed on the substrate surface in advance.
S420: as shown in fig. 6b, a layer of dry film 24 is covered on the surface of the substrate; then, as shown in fig. 6c, the dry film 24 is etched to remove the dry film 24 outside the preset area of the substrate surface, and the dry film 24 in the preset area of the substrate surface is used as the barrier layer 20.
It should be noted that, according to the material type of the dry film, the dry film 24 outside the preset area of the substrate surface may be removed by etching means of physical etching or exposure and development.
S430: as shown in fig. 6d, the radio frequency device 30, i.e. the first 31 and the second 32 radio frequency device, and the other radio frequency device 33 are soldered.
Similar to forming a solder mask layer as a barrier layer on a predetermined area of the substrate surface, in this embodiment, the thickness d4 of the dry film 24 may be just equal to or slightly greater than the distance d2 between the surface of the second rf device 32 facing the substrate 10 and the substrate surface, where a range where d4 is slightly greater than d2 refers to a range where the barrier layer 20 and the surface of the second rf device 32 facing the substrate 10 can be ensured to be tightly adhered without causing physical damage to the second rf device 32 under the condition of micro deformation.
In this embodiment, the height of the bump 311 of the first rf device 31 and the height of the bump 322 of the second rf device 32 may be set so that the distance d3 between the surface of the first rf device 31 facing the substrate 10 and the substrate surface is greater than the distance d2 between the surface of the second rf device 32 facing the substrate 10 and the substrate surface, so that the gap between the first rf device 31 and the substrate surface may be exposed while the barrier layer 20 and the surface of the second rf device 32 face the substrate 10, at this time, the front projection of the barrier layer 20 on the substrate surface may overlap with the front projection of the first rf device 31 on the substrate surface, or may not overlap with the front projection of the barrier layer 20 on the substrate surface, even if the front projection of the barrier layer 20 on the substrate surface overlaps with the front projection of the first rf device 31 on the substrate surface, the gap between the first rf device 31 and the substrate surface may still be exposed, so that the plastic package material may fill into the gap between the first rf device 31 and the substrate 10 when the plastic package material is subsequently performed.
S440: as shown in fig. 6e, the molding material 40 is filled, so that the molding material 40 fills the gap between the first rf device 31 and the substrate 10 and covers the first rf device 31, the second rf device 32, the barrier layer 20, and the substrate surface.
Fig. 6f further shows a schematic bottom view of the package structure shown in fig. 6e along the surface of the substrate, wherein the dashed box corresponds to the cavity K1, that is, corresponds to the functional region 321 of the second rf device 32, and it can be seen that, in this embodiment, the bump 322 of the second rf device 32 is located outside the cavity K1, and the barrier layer 20 is located on a side of the bump 322 of the second rf device 32 facing away from the cavity K1.
Further optionally, in addition to steps S410 to S420, the front projection of the barrier layer 20 on the substrate surface may be located outside the front projection of the first rf device 31 on the substrate surface, that is, in the direction perpendicular to the substrate surface, where the barrier layer 20 and the first rf device 31 are not overlapped, so that a larger opening is reserved to allow the molding compound 40 to fill the gap between the first rf device 31 and the substrate surface.
Alternatively, a multilayer dry film constituting the barrier layer may be formed similarly to the case of a multilayer solder resist constituting the barrier layer, as the case may be.
As shown in the package structure of fig. 3d and the package structure of fig. 6e, it can be seen that the barrier layer 20 may have a single layer structure; as shown in fig. 5d, the barrier layer 20 may also have at least two layers stacked along the direction away from the surface of the substrate, i.e., a multilayer structure, and when the barrier layer 20 has a multilayer structure (such as a multilayer solder resist layer), the adhesion tightness between the barrier layer 20 and the surface of the second radio frequency device 32 facing the substrate 10 can be further ensured compared with the case that the barrier layer 20 has a single layer structure, so as to avoid the chip from being damaged by external stress.
As shown in fig. 3d and the corresponding schematic bottom view shown in fig. 3e, as shown in fig. 5d and the corresponding schematic bottom view shown in fig. 5e, and as shown in fig. 6e and the corresponding schematic bottom view shown in fig. 6f, the bump 322 of the second rf device 32 is located at the outer side of the cavity K1, and the barrier layer 20 is located at the side of the bump 322 of the second rf device 32 facing away from the cavity K1, but the application is not limited thereto, and the barrier layer 20 may also be located at the side of the bump 322 of the second rf device 32 facing away from the cavity K1, or may be located at the same time on the side of the bump 322 of the second rf device 32 facing away from the cavity K1 and the side of the bump 322 of the second rf device 32 facing away from the cavity K1.
Alternatively, as shown in fig. 3d and the corresponding schematic bottom view of fig. 3e, as shown in fig. 5d and the corresponding schematic bottom view of fig. 5e, and as shown in fig. 6e and the corresponding schematic bottom view of fig. 6f, the blocking layer 20 includes a first blocking portion 201, and the first blocking portion 201 is located on a side of the bump 322 of the second radio frequency device 32 facing away from the cavity K1. In other embodiments of the present application, the blocking portion 20 may include a second blocking portion, where the second blocking portion is located on a side of the bump 322 of the second rf device 32 near the cavity K1; alternatively, the blocking portion 20 may include both a first blocking portion and a second blocking portion, where the first blocking portion is located on a side of the bump 322 of the second rf device 32 facing away from the cavity K1, and the second blocking portion is located on a side of the bump 322 of the second rf device 32 facing toward the cavity K1.
The following description proceeds with the example that the barrier layer 20 includes both the first barrier portion and the second barrier portion.
Fig. 7 a-7 e show schematic structural diagrams corresponding to the process steps in a selective packaging method in which the barrier layer 20 includes both a first barrier and a second barrier, and the selective packaging method includes:
s510: as shown in fig. 7a, a substrate 10 is provided, and the substrate surface has a plurality of pads 11, i.e., a plurality of pads 11 are formed on the substrate surface in advance.
S520: as shown in fig. 7b, a barrier layer 20 is formed in a preset area on the surface of the substrate, where the barrier layer 20 includes a first barrier portion 201 and a second barrier portion 202, the first barrier portion 201 is located on a side, away from the cavity K1, of the pad 11 corresponding to the bump 322 of the second radio frequency device 32, the second barrier portion 202 is located on a side, close to the cavity K1, of the pad 11 corresponding to the bump 322 of the second radio frequency device 32, and a thickness of the barrier layer 20 (including the first barrier portion 201 and the second barrier portion 202) is equal to or slightly greater than a height of the cavity K1.
It should be noted that, although the second blocking portion 202 is located on the bump 322 side of the second rf device 32 near the cavity K1, the second blocking portion 202 is still located outside the cavity K1 and surrounds the cavity K1.
S530: as shown in fig. 7c, the radio frequency device 30, i.e. the first 31 and the second 32 radio frequency device, and the other radio frequency device 33 are soldered.
In this embodiment, the first blocking portion 201 and the second blocking portion 202 are both attached to the surface of the second rf device 32 facing the substrate 10.
S540: as shown in fig. 7d, the molding material 40 is filled, so that the molding material 40 fills the gap between the first rf device 31 and the substrate 10 and covers the first rf device 31, the second rf device 32, the barrier layer 20, and the substrate surface.
It should be noted that, in addition to the portion of the surface of the second rf device 32 facing the substrate 10 corresponding to the functional area 321, other portions may be provided with bumps 322, in the process of correspondingly welding the bumps 322 of the second rf device 32 and the bonding pads 11 on the surface of the substrate, some welding materials or other contaminants may also enter the cavity K1, in this embodiment, the second blocking portion 202 is disposed on the side of the bumps 322 of the second rf device 32 close to the cavity K1 and still is disposed on the outside of the cavity K1, surrounding the cavity K1, and the second blocking portion 202 is attached to the surface of the second rf device 32 facing the substrate 10, so that the material or other contaminants in the welding process can be effectively prevented from entering the cavity K1 to affect the functional area 321 of the second rf device 32, and further affect the performance of the second rf device 32.
It will be appreciated that when the first blocking portion 201 is attached to the surface of the second rf device 32 facing the substrate 10, the first blocking portion 201 may block the molding compound 40 from entering the cavity K1 because the first blocking portion 201 surrounds the cavity K1. When the second blocking portion 202 is attached to the surface of the second rf device 32 facing the substrate 10, the second blocking portion 202 also surrounds the cavity K1 and is located on the side of the bump 322 of the second rf device 32 facing away from the cavity K1, so that the second blocking portion 202 can not only block the plastic molding material 40 from entering the cavity K1, but also avoid the material or other pollutants in the welding process from entering the cavity K1. It can be seen that if only the molding compound 40 is blocked from entering the cavity K1, at least one of the first blocking portion 201 and the second blocking portion 202 may be bonded to the surface of the second rf device 32 facing the substrate 10, that is, the first blocking portion 201 is bonded to the surface of the second rf device 32 facing the substrate 10, or the second blocking portion 202 is bonded to the surface of the second rf device 32 facing the substrate 10, or both the first blocking portion 201 and the second blocking portion 202 are bonded to the surface of the second rf device 32 facing the substrate 10.
Fig. 7e further illustrates a schematic bottom view of the package structure shown in fig. 7d along the surface of the substrate, and as shown in fig. 7e, since the cavity K1 is square, the second blocking portion 202 may be square to surround the cavity K1 and isolate the bump 322 of the second rf device 32 and the corresponding pad 11 from the cavity K1. It is understood that the shape of the second blocking portion 202 may vary according to the shape variation of the cavity K1. Fig. 8 and 9 are schematic bottom views of another two package structures along the surface of the substrate, which are obtained by using the selective packaging method provided in steps S510-S540, respectively, and as shown in fig. 8 and 9, since the cavity K1 is in a cross shape, the second blocking portion 202 may have four L shapes to surround the cavity K1 and isolate the bump 322 of the second rf device 32 and the corresponding pad 11, where the difference between fig. 8 and 9 is that the gap shape between the blocking layer 20 and the bump 322 of the second rf device 32 is different.
It should be noted that, in this application, for convenience of description, the barrier layer 20 is divided into the first barrier portion 201 and the second barrier portion 202 by taking the bump of the second radio frequency device 32 as a boundary, where the first barrier portion 201 is located on a side of the bump 322 of the second radio frequency device 32 facing away from the cavity K1, and the second barrier portion 202 is located on a side of the bump 322 of the second radio frequency device 32 near the cavity K1, but in reality, the first barrier portion 201 and the second barrier portion 202 may be separately disposed, as shown in fig. 7e, or the first barrier portion 201 and the second barrier portion 202 may also be in communication, as shown in fig. 8 and 9. The laminated structures of the first barrier 201 and the second barrier 202 may be the same or different; the thicknesses of the first barrier 201 and the second barrier 202 may be the same or different, as the case may be.
Alternatively, as shown in fig. 7d and the corresponding bottom schematic view of fig. 7e, the first blocking portion 201 and the second blocking portion 202 may be made of solder resist materials; alternatively, the first barrier portion 201 and the second barrier portion 202, which are both solder resist materials in the package structure shown in fig. 7d, may be replaced by the dry film 24, so as to obtain the package structure shown in fig. 10a and a corresponding schematic bottom view along the substrate surface shown in fig. 10 b.
In the package structure shown in fig. 7d, the first barrier 201 and the second barrier 202 are both of a single-layer structure. Further optionally, fig. 11 shows a schematic diagram of a package structure provided in this embodiment, and it can be seen that the first blocking portion 201 located on a side of the bump 322 of the second radio frequency device 32 away from the cavity K1 may also be a multi-layer structure, so as to improve the tightness of adhesion between the first blocking portion 201 and the second radio frequency device 32, especially when the first blocking portion 201 is a multi-layer solder mask, the second radio frequency device 32 may be welded before the solder mask is not fully cured, and then thoroughly cured, so that the first blocking portion 201 and the second radio frequency device 32 may be ensured to be closely adhered, and external stress is avoided from damaging the second radio frequency device 32. Similarly, the second blocking portion 202 located on the side of the bump 322 of the second rf device 32 near the cavity K1 may also have a multi-layer structure.
Fig. 12 shows a schematic diagram of another package structure provided in this embodiment of the present application, as shown in fig. 12, the second blocking portion 202 is attached to the surface of the second radio frequency device facing the substrate 10, and the thickness of the first blocking portion 201 is smaller than that of the second blocking portion 202, that is, the thickness of the first blocking portion 201 is smaller, so that the plastic package material 40 can also fill the gap between the second radio frequency device 32 and the surface of the substrate, and is located at one side of the second blocking portion 202 facing away from the cavity K1, that is, the plastic package material 40 can enter into the bump 322 and the area of the pad 11 at the bottom of the second radio frequency device 32, thereby further protecting the cavity K1.
Based on the package structure shown in fig. 12, it may be understood that in some embodiments of the present application, only the second blocking portion 302 located on the side of the bump 322 of the second radio frequency device 32 near the cavity K1 may be provided, and the second blocking portion is attached to the surface of the second radio frequency device 32 facing the substrate 10, where the first blocking portion 301 is not provided, and the molding material and the welding material and other pollutants in the welding process may be blocked from entering the cavity K1 by the second blocking portion 302.
Fig. 13a to 13d are schematic structural diagrams corresponding to each process step in another alternative packaging method according to an embodiment of the present application, where the alternative packaging method includes:
S610: as shown in fig. 13a, a substrate 10 is provided, and the substrate surface has a plurality of pads 11, i.e., a plurality of pads 11 are formed on the substrate surface in advance.
S620: as shown in fig. 13b, a barrier layer 20 is formed in a predetermined region of the substrate surface.
S630: as shown in fig. 13c, the rf devices 30, i.e., the first rf device 31 and the second rf device 32, and the other rf devices 33 are soldered; wherein, during the preparation process of the second rf device 32, at least one circle of metal layer 323 surrounding the functional area 321 of the second rf device 32 is formed on the surface of the second rf device 32, as shown in fig. 13e, the circle of metal layer 323 includes a plurality of metal segments arranged at intervals;
in this embodiment, the adhesion between the barrier layer 20 and the surface of the second rf device 32 facing the substrate 10 includes:
the barrier layer 20 is bonded to the surface of the metal layer 323 facing the substrate 10.
That is, when the second rf device 32 is soldered, the metal layer 323 on the surface of the second rf device 32 is placed on the barrier layer 20 toward the substrate 10 side, so that the barrier layer 20 is bonded to the surface of the metal layer 323 toward the substrate 10, that is, the barrier layer 20 is bonded to the surface of the second rf device 32 toward the substrate 10.
Optionally, when the connection layer of the second rf device 32 for signal transmission is prepared, at least one circle of metal layer 323 surrounding the functional area 321 is formed on the surface of the second rf device 32, so that no additional process steps are added, and the method is simple and easy to operate.
In order to prevent the coupling, the metal layer 323 includes a plurality of metal segments arranged at intervals, but the gap between two adjacent metal segments is small, so that the metal layer 323 and the barrier layer 20 together form a barrier structure between the second rf device 32 and the substrate surface, and surround the cavity K1 to block the molding material from entering the cavity K1.
S640: as shown in fig. 13d, the molding material 40 is filled, so that the molding material 40 fills the gap between the first rf device 31 and the substrate 10 and covers the first rf device 31, the second rf device 32, the barrier layer 20, and the substrate surface.
Fig. 13e further illustrates a bottom view of the package structure of fig. 13d along the surface of the substrate, wherein at least one turn of the metal layer 323 on the surface of the second rf device 32 comprises one turn of the metal layer.
Further alternatively, as shown in fig. 14a and 14b, at least one circle of metal layer 323 on the surface of the second radio frequency device 32 includes a first circle of metal layer and a second circle of metal layer located on one side of the first circle of metal layer facing away from the cavity K1, specifically, metal segments in the first circle of metal layer correspond to gaps between two adjacent metal segments in the second circle of metal layer, metal segments in the second circle of metal layer correspond to gaps between two adjacent metal segments in the first circle of metal layer, that is, metal segments in the first circle of metal layer and metal segments in the second circle of metal layer are staggered, so that gaps between discontinuous metal segments in the two circles of metal layers are spaced apart, and the gaps in one circle of metal layer are blocked by metal segments in the other circle of metal layer, thereby preventing the molding material 40 from entering the cavity K1 through the metal layer 323 to a greater extent.
It will be appreciated that in the above embodiment, at least one circle of metal layer 323 surrounding the functional area 321 is formed on the surface of the second rf device 32, and the at least one circle of metal layer 323 can also be used as an electromagnetic shielding layer, so as to effectively shield external electromagnetic interference and prevent the second rf device 32 from interfering with other rf devices.
It should be noted that the foregoing embodiment only shows the case where one turn of the metal layer 323 and two turns of the metal layer 323 surrounding the functional area 321 are formed on the surface of the second rf device 32, and is not limited to this application, and in other embodiments of this application, at least three turns of the metal layer 323 surrounding the functional area 321 may be formed on the surface of the second rf device 32, as the case may be.
Since the gap between the metal segments in the metal layer 323 in one circle is smaller when the metal layer 323 surrounding the functional area 321 is formed on the surface of the second rf device 32, that is, the metal layer 323 in one circle can effectively block the molding material 40 from entering the cavity K1 in combination with the barrier layer 20, when at least two circles of metal layers 323 are formed on the surface of the second rf device 32, the adjacent two circles of metal layers 323 can be arranged identically, that is, the metal segments in the adjacent two circles of metal layers 323 correspond to each other, the metal segments in the first circle of metal layers and the metal segments in the second circle of metal layers are arranged alternately, which can avoid the molding material 40 from entering the cavity K1 through the metal layer 323 to a greater extent.
Alternatively, any turn of metal layer 323 may be located on the side of the bump 322 of the second rf device 32 facing away from the cavity K1, or may be located on the side of the bump 322 of the second rf device 32 near the cavity K1, but all located outside the functional area 321, surrounding the functional area 321, thereby surrounding the cavity K1.
The embodiment of the application also provides a radio frequency module, which comprises a packaging structure obtained by adopting the selective packaging method provided by any embodiment, or comprises the packaging structure provided by any embodiment. Because the selective packaging method and the packaging structure obtained by using the selective packaging method provided by the embodiment of the present application have been described in detail, the details are not repeated here.
In the description, each part is described in a parallel and progressive mode, and each part is mainly described as a difference with other parts, and all parts are identical and similar to each other.
The features described in the various embodiments of the present disclosure may be interchanged or combined with one another in the description to enable those skilled in the art to make or use the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (15)

1. A method of selective encapsulation comprising:
providing a substrate, wherein the surface of the substrate is provided with a plurality of bonding pads;
forming a barrier layer in a preset area on the surface of the substrate;
the welding radio frequency device comprises a first radio frequency device and a second radio frequency device, wherein the salient point of the first radio frequency device is correspondingly welded with part of the bonding pad, and the salient point of the second radio frequency device is correspondingly welded with the other part of the bonding pad; the second radio frequency device is provided with a functional area, a cavity is arranged between the functional area and the surface of the substrate, the blocking layer surrounds the cavity, the blocking layer is attached to the surface of the second radio frequency device, which faces the substrate, and the blocking layer exposes a gap between the first radio frequency device and the surface of the substrate;
filling a plastic package material, so that the plastic package material fills a gap between the first radio frequency device and the surface of the substrate and covers the first radio frequency device, the second radio frequency device, the barrier layer and the surface of the substrate.
2. The selective packaging method of claim 1, wherein forming a barrier layer at a predetermined area of the substrate surface comprises:
And forming at least one layer of solder mask layer serving as the barrier layer in a preset area on the surface of the substrate.
3. The selective packaging method of claim 1, wherein forming a barrier layer at a predetermined area of the substrate surface comprises:
covering a layer of dry film on the surface of the substrate;
and etching the dry film, removing the dry film outside the preset area on the surface of the substrate, and taking the dry film in the preset area on the surface of the substrate as the barrier layer.
4. The selective packaging method according to claim 1, wherein at least one circle of metal layer surrounding the functional area is formed on the surface of the second radio frequency device during the preparation process of the second radio frequency device, and one circle of metal layer comprises a plurality of metal segments which are arranged at intervals;
when the radio frequency device is welded, the blocking layer is attached to the surface of the second radio frequency device, which faces the substrate, and the blocking layer comprises:
the barrier layer is attached to the surface of the metal layer facing the substrate.
5. A package structure, comprising:
a substrate, the surface of which is provided with a plurality of bonding pads;
the barrier layer is positioned in a preset area on the surface of the substrate;
The radio frequency device comprises a first radio frequency device and a second radio frequency device, wherein the salient point of the first radio frequency device is correspondingly welded with part of the bonding pad, and the salient point of the second radio frequency device is correspondingly welded with the other part of the bonding pad; the second radio frequency device is provided with a functional area, a cavity is arranged between the functional area and the surface of the substrate, the blocking layer surrounds the cavity, the blocking layer is attached to the surface of the second radio frequency device, which faces the substrate, and the blocking layer exposes a gap between the first radio frequency device and the surface of the substrate;
and the plastic packaging material fills the gap between the first radio frequency device and the surface of the substrate and covers the first radio frequency device, the second radio frequency device, the barrier layer and the surface of the substrate.
6. The package structure of claim 5, wherein the bump of the second rf device is located outside the cavity, and the barrier layer includes a first barrier portion, and the first barrier portion is located on a side of the bump of the second rf device facing away from the cavity.
7. The package structure of claim 5, wherein the bump of the second rf device is located outside the cavity, and the barrier layer includes a second barrier portion, and the second barrier portion is located on a side of the bump of the second rf device that is close to the cavity.
8. The package structure of claim 5, wherein the bump of the second rf device is located outside the cavity, the barrier layer includes a first barrier portion and a second barrier portion, at least one of the first barrier portion and the second barrier portion is attached to a surface of the second rf device facing the substrate, the first barrier portion is located on a side of the bump of the second rf device facing away from the cavity, and the second barrier portion is located on a side of the bump of the second rf device facing the cavity.
9. The package structure of claim 8, wherein the second barrier is attached to a surface of the second rf device facing the substrate, and the thickness of the first barrier is less than the thickness of the second barrier;
the plastic packaging material is also filled in a gap between the second radio frequency device and the surface of the substrate, and is positioned at one side of the second blocking part, which is away from the cavity.
10. The package structure of claim 5, wherein the front projection of the barrier layer on the substrate surface is outside the front projection of the first rf device on the substrate surface.
11. The package structure of claim 5, wherein a distance between a surface of the first rf device facing the substrate and the substrate surface is greater than a distance between a surface of the second rf device facing the substrate and the substrate surface.
12. The package structure according to claim 5, wherein the barrier layer is a single-layer structure or at least two-layer structure stacked in a direction away from the substrate surface.
13. The package structure of claim 5, wherein a surface of the second rf device facing the substrate has at least one turn of a metal layer surrounding the functional region, one turn of the metal layer comprising a plurality of metal segments arranged at intervals;
the barrier layer is attached to the surface of the metal layer facing the substrate.
14. The package structure of claim 13, wherein the at least one turn of metal layer comprises a first turn of metal layer and a second turn of metal layer located on a side of the first turn of metal layer facing away from the functional region, the metal segments in the first turn of metal layer corresponding to gaps between adjacent two of the metal segments in the second turn of metal layer, the metal segments in the second turn of metal layer corresponding to gaps between adjacent two of the metal segments in the first turn of metal layer.
15. A radio frequency module comprising a package structure obtained by the selective packaging method according to any one of claims 1-4, or comprising a package structure according to any one of claims 5-14.
CN202311281493.6A 2023-09-28 2023-09-28 Selective packaging method, packaging structure and radio frequency module Pending CN117334582A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311281493.6A CN117334582A (en) 2023-09-28 2023-09-28 Selective packaging method, packaging structure and radio frequency module

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311281493.6A CN117334582A (en) 2023-09-28 2023-09-28 Selective packaging method, packaging structure and radio frequency module

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CN117334582A true CN117334582A (en) 2024-01-02

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