Radio frequency module and manufacturing method therefor

Abstract

Provided in the present invention are a radio frequency module and a manufacturing method therefor. The manufacturing method comprises: providing an intermediate plastic packaging structure, wherein the intermediate plastic packaging structure comprises: a first electronic element, which comprises a filter chip and a non-filter chip or / and a passive element; a first plastic packaging layer, which wraps at least a back face and side walls of the first electronic element; retaining walls, which are located on two sides of a front face of the filter chip; and an isolation layer, which covers the retaining walls and defines a cavity with the retaining walls and the front face of the filter chip, the isolation layer further covering at least part of a front face of the non-filter chip or / and the passive element; forming at least one redistribution layer, wherein the redistribution layer is electrically connected to a front face of the first electronic element; and forming a first pad, wherein the first pad is electrically connected to the redistribution layer. In the present invention, WLP filter manufacturing and fan-out packaging are combined to achieve the radio frequency module, and a filter cavity and module packaging are completed simultaneously, which can effectively reduce the manufacturing complexity of a radio frequency front-end module.

Description

Radio frequency module and manufacturing method thereof Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a radio frequency module and a manufacturing method thereof. Background Art

[0002] The RF front-end is the core module of the mobile terminal communication system. It is an intermediate module located between the RF transceiver and the antenna. Its function is to perform signal processing such as power amplification, filtering, and switching of RF signals. It is a necessary module for mobile terminal devices to realize wireless communication functions such as cellular network connection, Wi-Fi, Bluetooth, and GPS.

[0003] Among them, RF front-end functional components mainly include power amplifiers (PAs), low-noise amplifiers (LNAs), RF switches (Switches), filters (Filters), duplexers (Duplexers), and antenna tuners. Depending on the application scenario and the required level of integration of the terminal equipment, these components are usually integrated to a certain extent to form modules according to the requirements of transceiver functions and the supported frequency band range. RF front-end modules are conducive to reducing size and improving integration. With the development of communication technology, the overall proportion of RF front-end module products is on an upward trend and will gradually replace traditional discrete devices.

[0004] Traditional RF front-end modules are created by soldering or wire-bonding multiple components to one or both sides of a prefabricated substrate, followed by encapsulation and cutting. As integration increases, feature sizes decrease, and defects introduced during soldering, bonding, and encapsulation become increasingly difficult to overcome, further impacting size.

[0005] Furthermore, the number of frequency bands supported by mobile phone RF front-ends has continued to increase, from a maximum of no more than five to over 50. This evolution has led to an exponential increase in the number of RF front-end components, particularly a significant increase in the number of RF filters. RF filters often use acoustic filters, which require a cavity to ensure proper function.

[0006] WLP (Wafer Level Packaging) filters with pre-built cavities are often used in RF front-end modules. The main disadvantages of this type of filter are: 1. The manufacturing process is complex and the cost is high; 2. The filter wafer is relatively thin and easily broken during the WLP packaging process, resulting in yield loss; 3. It is extremely sensitive to molding pressure during the plastic encapsulation process, which can easily cause cavity collapse and lead to device failure. Summary of the Invention

[0007] The purpose of the present invention is to provide a radio frequency module and a manufacturing method thereof, which adopts WLP filter manufacturing combined with fan-out packaging, and the filter cavity and module packaging are completed at the same time, which can effectively reduce the manufacturing complexity of the radio frequency front-end module and reduce the filter wafer breakage rate.

[0008] To solve the above technical problems, according to a first aspect of the present invention, a method for manufacturing a radio frequency module is provided, comprising the following steps:

[0009] An intermediate plastic packaging structure is provided, comprising: a first electronic component, the first electronic component comprising a filter chip and a non-filter chip and / or a passive component; a first plastic packaging layer covering at least the back surface and sidewalls of the first electronic component; retaining walls located on both sides of the front surface of the filter chip; an isolation layer covering the retaining walls and forming a cavity with the retaining walls and the front surface of the filter chip, the isolation layer also covering at least a portion of the front surface of the non-filter chip and / or the passive component;

[0010] forming at least one redistribution layer on the intermediate plastic package structure, wherein the redistribution layer is electrically connected to the front surface of the first electronic component; and

[0011] A first pad is formed on the redistribution layer, and the first pad is electrically connected to the redistribution layer.

[0012] Optionally, the method of providing the intermediate plastic packaging structure includes:

[0013] Manufacturing a first electronic component wafer, wherein the first electronic component wafer includes a filter wafer and a non-filter wafer and / or a passive component, forming a retaining wall on the filter wafer, and dividing the first electronic component wafer into individual first electronic components;

[0014] Providing a temporary bonding structure, and mounting the first electronic component with its front side facing downward on the temporary bonding structure;

[0015] forming a first plastic encapsulation layer on the temporary bonding structure, wherein the first plastic encapsulation layer covers the back surface and sidewalls of the first electronic component, the outer sidewalls of the retaining wall, and a portion of the temporary bonding structure;

[0016] removing the temporary bonding structure to expose the front surface of the first electronic component; and

[0017] An isolation layer is formed on the front surface of the first electronic component, and the isolation layer, the retaining wall and the front surface of the filter chip constitute a cavity.

[0018] Optionally, the method of providing the intermediate plastic packaging structure includes:

[0019] Manufacturing a first electronic component wafer, wherein the first electronic component wafer includes a filter wafer and a non-filter wafer and / or a passive component, forming a retaining wall on the filter wafer, and dividing the first electronic component wafer into individual first electronic components;

[0020] providing a temporary bonding structure, and forming an isolation layer corresponding to the retaining wall on the temporary bonding structure;

[0021] Mounting the first electronic component with its front side facing downward on the temporary bonding structure, wherein the isolation layer, the retaining wall and the front side of the filter chip form a cavity;

[0022] forming a first plastic encapsulation layer on the temporary bonding structure, wherein the first plastic encapsulation layer covers the back surface and side walls of the first electronic component, the outer side walls of the retaining wall, and a portion of the temporary bonding structure; and

[0023] The temporary bonding structure is removed to expose the front surface of the first electronic component.

[0024] Optionally, when the first electronic component includes a filter chip and a non-filter chip, or when the first electronic component includes a filter chip, a non-filter chip and a passive component, and the passive component pad is located on the front side of the passive component, after mounting the first electronic component with the front side facing down on the temporary bonding structure and before forming the first plastic encapsulation layer, the method further includes: forming a shielding layer, wherein the shielding layer covers at least the back side, side wall and part of the temporary bonding structure of the first electronic component;

[0025] After removing the temporary bonding structure, the method further includes: removing a portion of the shielding layer to expose a portion of the first plastic packaging layer.

[0026] Optionally, after forming the first pad, the manufacturing method further includes:

[0027] forming a second electronic component with a second bump and the first bump on the first pad respectively;

[0028] forming a second plastic encapsulation layer, wherein the second plastic encapsulation layer covers the second electronic component, the first bump, and a portion of the redistribution layer; and

[0029] A portion of the second plastic packaging layer is removed until the second electronic component and the first bump are exposed.

[0030] Optionally, the second electronic component includes a non-filter chip and / or a passive component.

[0031] Optionally, the first bump is a solder ball; and after removing part of the second plastic encapsulation layer, the method further includes:

[0032] removing a portion of the second plastic encapsulation layer around the first bump; and

[0033] The first bumps are reflowed so that surfaces of the first bumps are higher than a surface of the second plastic encapsulation layer.

[0034] Optionally, the first bump is a column; and after removing part of the second plastic encapsulation layer, the method further includes: forming a second pad on an upper surface of the first bump.

[0035] To solve the above technical problems, according to a second aspect of the present invention, a radio frequency module is provided, comprising:

[0036] An intermediate plastic encapsulation structure, the intermediate plastic encapsulation structure comprising: a first electronic component, the first electronic component comprising a filter chip and a non-filter chip and / or a passive component; a first plastic encapsulation layer covering at least the back surface and side walls of the first electronic component; retaining walls located on both sides of the front surface of the filter chip; an isolation layer covering the retaining walls and forming a cavity with the retaining walls and the front surface of the filter chip, the isolation layer also covering at least a portion of the front surface of the non-filter chip and / or the passive component;

[0037] at least one redistribution layer located on the intermediate plastic package structure, the redistribution layer being electrically connected to the front surface of the first electronic component; and

[0038] A first pad is located on the redistribution layer, and the first pad is electrically connected to the redistribution layer.

[0039] Optionally, when the first electronic component includes a filter chip and a non-filter chip, or when the first electronic component includes a filter chip, a non-filter chip and a passive component, and the passive component pad is located on the front of the passive component, the RF module also includes a shielding layer, and the shielding layer covers at least the back and side walls of the first electronic component.

[0040] Optionally, the radio frequency module further includes:

[0041] a first bump located on the first pad and a second electronic component having a second bump; and

[0042] A second plastic encapsulation layer covers the second electronic component and side walls of the first bump.

[0043] Optionally, the second electronic component includes a non-filter chip and / or a passive component.

[0044] Optionally, the first bump is a solder ball, and a surface of the first bump is higher than a surface of the second plastic packaging layer.

[0045] Optionally, the first bump is a column; and a second pad is formed on a top surface of the first bump.

[0046] Optionally, an interdigital transducer and filter chip pads located on both sides of the interdigital transducer are formed on the front side of the filter chip; the interdigital transducer is located in the cavity, the retaining wall and the isolation layer both have openings to expose at least part of the filter chip pads, and the redistribution layer is electrically connected to the filter chip pads.

[0047] Optionally, the thickness of the retaining wall is greater than the sum of the thickness of the interdigital transducer and the thickness of the pad of the filter chip.

[0048] Optionally, the cross-sectional area of ​​the opening of the retaining wall on the side close to the filter chip is smaller than or equal to the cross-sectional area on the side away from the filter chip; the cross-sectional area of ​​the opening of the isolation layer on the side close to the filter chip is smaller than or equal to the cross-sectional area on the side away from the filter chip.

[0049] Optionally, a cross-sectional area of ​​the opening of the isolation layer on a side close to the filter chip is greater than or equal to a cross-sectional area of ​​the opening of the retaining wall at a corresponding position on a side away from the filter chip.

[0050] Optionally, a non-filter chip pad is formed on the front of the non-filter chip, and the isolation layer has an opening to expose at least a portion of the non-filter chip pad; a passive component pad is formed on the front of the passive component, and the isolation layer has an opening to expose at least a portion of the passive component pad.

[0051] Optionally, the cross-sectional area of ​​the opening of the isolation layer on the side close to the non-filter chip is smaller than or equal to the cross-sectional area on the side away from the non-filter chip; the cross-sectional area of ​​the opening of the isolation layer on the side close to the passive component is smaller than or equal to the cross-sectional area on the side away from the passive component.

[0052] To sum up, in the RF module and its manufacturing method provided by the present invention, an intermediate plastic packaging structure is first provided, and the intermediate plastic packaging structure includes: a first electronic component, the first electronic component includes a filter chip and a non-filter chip or / and a passive component; a first plastic packaging layer that at least covers the back and side walls of the first electronic component; a retaining wall located on both sides of the front of the filter chip; an isolation layer that covers the retaining wall and forms a cavity with the retaining wall and the front of the filter chip, and the isolation layer also covers at least part of the front of the non-filter chip or / and the passive component; then at least one redistribution layer is formed, and the redistribution layer is electrically connected to the front of the first electronic component; then a first soldering pad is formed, and the first soldering pad is electrically connected to the redistribution layer. The present invention adopts a combination of WLP filter production and fan-out packaging to realize the radio frequency module. The filter cavity and module packaging are completed at the same time, which can effectively reduce the complexity of radio frequency front-end module production. At the same time, the filter chip completes the entire packaging process in a single chip method, thereby greatly reducing the high fragmentation rate of the filter wafer packaging. Secondly, at least one layer of redistribution layer is used to replace the traditional substrate to provide interconnection, which greatly improves the interconnection density while reducing the thickness. In addition, the filter cavity will not be subjected to injection molding pressure during the entire packaging process, eliminating the cavity collapse caused by the secondary plastic packaging process. At the same time, the production method described in the present invention can realize a smaller three-dimensional radio frequency front-end module, which can obtain a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] FIG1 is a flow chart of a method for manufacturing a radio frequency module provided by an embodiment of the present invention.

[0054] 2 to 10 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the first embodiment of the present invention.

[0055] 11 to 19 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the second embodiment of the present invention.

[0056] 20 to 23 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the third embodiment of the present invention.

[0057] 24 to 26 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the fourth embodiment of the present invention.

[0058] 27 to 30 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the fifth embodiment of the present invention.

[0059] 31 to 34 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the sixth embodiment of the present invention.

[0060] 35 to 39 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the seventh embodiment of the present invention.

[0061] 40 to 44 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in the eighth embodiment of the present invention.

[0062] Figure 45 is a cross-sectional schematic diagram of a retaining wall opening provided in one embodiment of the present invention.

[0063] FIG46 is a schematic cross-sectional view of an opening in an isolation layer provided in accordance with an embodiment of the present invention.

[0064] Explanation of the accompanying drawings: 1-temporary bonding structure; 11-carrier; 12-bonding layer; 2-filter chip; 21-filter chip substrate; 22-interdigital transducer; 23-filter chip pad; 24-retaining wall; 25-cavity; 3-non-filter chip; 31-non-filter chip substrate; 32-non-filter chip pad; 4-passive component; 41-passive component body; 42-passive component pad; 51-first plastic packaging layer; 52-second plastic packaging layer; 6-isolation layer; 7-rewiring layer; 71-metal circuit layer; 72-dielectric layer; 8-first pad; 9-first bump; 10-solder mask layer; 13-shielding layer; 14-second electronic component; 141-second electronic component substrate; 142-second bump; 15-second pad. DETAILED DESCRIPTION

[0065] To make the objects, advantages, and features of the present invention more clearly apparent, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale. They are only used to conveniently and clearly assist in illustrating the purposes of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structure. In particular, different drawings may need to illustrate different focuses and sometimes use different scales.

[0066] As used in the present invention, the singular forms "a", "an" and "the" include plural objects, unless the content clearly indicates otherwise. As used in the present invention, the term "or" is generally used in a sense including "and / or", unless the content clearly indicates otherwise. As used in the present invention, the term "several" is generally used in a sense including "at least one", unless the content clearly indicates otherwise. As used in the present invention, the term "at least two" is generally used in a sense including "two or more", unless the content clearly indicates otherwise. In addition, the terms "first", "second" and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, unless the content clearly indicates otherwise.

[0067] FIG1 is a flow chart of a method for manufacturing a radio frequency module according to an embodiment of the present invention. As shown in FIG1 , the method for manufacturing a radio frequency module includes the following steps:

[0068] S1: Providing an intermediate plastic packaging structure, the intermediate plastic packaging structure comprising: a first electronic component, the first electronic component comprising a filter chip and a non-filter chip and / or a passive component; a first plastic packaging layer covering at least the back surface and side walls of the first electronic component; retaining walls located on both sides of the front surface of the filter chip; an isolation layer covering the retaining walls and forming a cavity with the retaining walls and the front surface of the filter chip, the isolation layer also covering at least a portion of the front surface of the non-filter chip and / or the passive component;

[0069] S2: forming at least one redistribution layer on the intermediate plastic package structure, wherein the redistribution layer is electrically connected to the front surface of the first electronic component; and

[0070] S3: forming a first pad on the redistribution layer, wherein the first pad is electrically connected to the redistribution layer.

[0071] The present invention adopts a combination of WLP filter production and fan-out packaging to realize the radio frequency module. The filter cavity and module packaging are completed at the same time, which can effectively reduce the complexity of radio frequency front-end module production. At the same time, the filter chip completes the entire packaging process in a single chip method, thereby greatly reducing the high fragmentation rate of the filter wafer packaging. Secondly, at least one layer of redistribution layer is used to replace the traditional substrate to provide interconnection, which greatly improves the interconnection density while reducing the thickness. In addition, the filter cavity will not be subjected to injection molding pressure during the entire packaging process, eliminating the cavity collapse caused by the secondary plastic packaging process. At the same time, the production method described in the present invention can realize a smaller three-dimensional radio frequency front-end module, which can obtain a wider range of applications.

[0072] The following describes in detail the method for manufacturing the radio frequency module of the present invention through specific embodiments.

[0073] Example 1

[0074] Figures 2 to 10 are schematic diagrams of the various steps of the method for manufacturing a radio frequency module according to the first embodiment of the present invention. Next, the method for manufacturing a radio frequency module according to the embodiment of the present invention will be described in detail with reference to Figures 1 and 2 to 10.

[0075] In step S1, please refer to Figure 8 and provide an intermediate plastic packaging structure, which includes: a first electronic component, the first electronic component including a filter chip 2 and a non-filter chip 3 and / or a passive component 4; a first plastic packaging layer 51 that at least covers the back and side walls of the first electronic component, retaining walls 24 located on both sides of the front of the filter chip 2, an isolation layer 6 that covers the retaining walls 24 and forms a cavity 25 with the retaining walls 24 and the front of the filter chip 2, and the isolation layer 6 also covers at least part of the front of the non-filter chip 3 and / or the passive component 4.

[0076] For example, the intermediate plastic packaging structure can be formed by the following sub-steps S11 to S16. In this embodiment, the first electronic component includes the filter chip 2, the non-filter chip 3 and the passive component 4 as an example for description.

[0077] Execute sub-step S11, referring to FIG. 2 to FIG. 4, to manufacture a first electronic component wafer, wherein the first electronic component wafer includes a filter wafer, a non-filter wafer, and a passive component, form a retaining wall 24 on the filter wafer, and divide the first electronic component wafer into single first electronic components.

[0078] In this embodiment, a filter wafer is manufactured, a retaining wall is formed on the filter wafer, and then the filter wafer is thinned and divided into single filter chips; at the same time, a non-filter wafer is manufactured, and the non-filter wafer is thinned and divided into single non-filter chips; at the same time, a passive component is manufactured and divided into single passive components.

[0079] Referring to Figure 2 , the filter chip 2 includes a filter chip substrate 21, an IDT 22 formed on the front surface of the filter chip substrate 21, and filter chip pads 23 located on both sides of the IDT 22. The surface on which the IDT 22 and the filter chip pads 23 are formed serves as the front surface of the filter chip 2, while the surface opposite the front surface serves as the back surface of the filter chip 2. The front surface of the filter chip 2 is the same surface as the front surface of the filter chip substrate 21.

[0080] Exemplarily, the material of the filter chip substrate 21 includes but is not limited to lithium niobate, lithium tantalate, silicon, or a multilayer material having a piezoelectric material layer. The interdigital transducer 22 is a single-layer film or a multilayer film composed of a metal material such as Ti (titanium), Al (aluminum), AlCu (aluminum copper), etc., and the surface of the interdigital transducer 22 can be covered with a silicon oxide or silicon nitride passivation layer to protect the interdigital transducer 22. The filter chip pad 23 is a single-layer film or a multilayer film composed of a metal material such as Ti, Al, AlCu, etc., and the surface of the filter chip pad 23 can also be covered with a silicon oxide or silicon nitride passivation layer, and the passivation layer has an opening to expose a portion of the filter chip pad 23.

[0081] Retaining walls 24 are formed on both sides of the front of the filter chip 2. The retaining walls 24 are located on both sides of the filter chip substrate 21. The retaining walls 24 have openings to expose at least part of the filter chip pads 23. In one embodiment of the present invention, please refer to FIG45 , the cross-sectional area of ​​the opening of the retaining wall 24 on the side close to the filter chip 2 (only the filter chip substrate 21 and the filter chip pads 23 are shown in the figure) is smaller than the cross-sectional area on the side away from the filter chip 2, that is, in the direction perpendicular to the filter chip substrate 21, the opening has a structure that is wide at the top and narrow at the bottom to facilitate the formation of the subsequent redistribution layer. In another embodiment of the present invention, please refer to FIG2 , the cross-sectional area of ​​the opening of the retaining wall 24 on the side close to the filter chip 2 is equal to the cross-sectional area on the side away from the filter chip 2.

[0082] In one embodiment of the present invention, the thickness of the retaining wall 24 is greater than the sum of the thickness of the IDT 22 and the thickness of the filter chip pad 23 , so as to ensure the height of the cavity formed subsequently.

[0083] For example, a barrier material layer is first formed on the front surface of the filter chip 2, covering the IDT 22, the filter chip pads 23, and the filter chip substrate 21. The barrier material layer is then patterned, leaving the barrier material layer on both sides of the filter chip 2 to form barrier walls 24. The barrier wall 24 can be made of, but is not limited to, a dry film material or photoresist having exposure properties.

[0084] Referring to Figure 3 , the non-filter chip 3 includes a non-filter chip substrate 31 and a non-filter chip pad 32 formed on the front surface of the non-filter chip substrate 31. The side with the non-filter chip pad 32 serves as the front surface of the non-filter chip 3, while the side opposite the front surface serves as the back surface of the non-filter chip 3. The front surface of the non-filter chip 3 is the same surface as the front surface of the non-filter chip substrate 31. The material of the non-filter chip substrate 31 can be selected from Si, SOI (silicon on insulator), GaAs (gallium arsenide), GaN (gallium nitride), or glass, depending on the device type. The non-filter chip pad 32 can be a multilayer film composed of Cu / Al / Cu.

[0085] Referring to Figure 4 , the passive component 4 includes a passive component body 41 and a passive component pad 42 formed on the passive component body 41. In this embodiment, the passive component pad 42 is formed on the front surface of the passive component body 41. In other embodiments, the passive component pad 42 may also be formed on other surfaces of the passive component body 41, such as the side surfaces. The front surface of the passive component 4 is the same as the front surface of the passive component body 41.

[0086] The passive components 4 include but are not limited to capacitors, inductors, resistors or LTCC filters. The passive component pads 42 are multi-layer films made of metal materials such as Cu, Ni, Ag, and Au, and have no Sn layer on the surface.

[0087] Sub-step S12 is performed. Referring to FIG. 5 , a temporary bonding structure 1 is provided, and the first electronic component is mounted face-down on the temporary bonding structure 1. In this embodiment, the filter chip 2, the non-filter chip 3, and the passive component 4 are mounted face-down on the temporary bonding structure 1. FIG. 5 shows two filter chips 2, one non-filter chip 3, and one passive component 4. The embodiment does not limit the number of filter chips 2, non-filter chips 3, and passive components 4.

[0088] Exemplarily, the temporary bonding structure 1 includes a carrier 11 and a bonding layer 12. The carrier 11 can be a hard carrier, such as a silicon wafer, a glass plate, or a metal panel. A hard carrier 11 provides better support. The bonding layer 12 can be a releasable adhesive layer that can be applied to the carrier 11 and adhere to a chip or device placed thereon. After the plastic packaging is completed, the carrier 11 can be easily peeled off and removed. Of course, the bonding layer 12 can also be other material layers known in the art.

[0089] Execute sub-step S13, as shown in FIG6 , to form a first plastic encapsulation layer 51 on the temporary bonding structure 1. The first plastic encapsulation layer 51 covers the back surface and sidewalls of the first electronic component, the outer sidewalls of the retaining wall 24, and a portion of the temporary bonding structure 1. The outer sidewalls of the retaining wall 24 refer to the sidewalls of the retaining wall 24 facing the outside of the filter chip 2, or the sidewalls of the retaining wall 24 facing away from the IDT 22.

[0090] For example, the first plastic encapsulation layer 51 can be formed by transfer film, compression film, lamination, etc. The first plastic encapsulation layer 51 is a thermosetting resin material containing inorganic fillers.

[0091] Execute sub-step S14, as shown in Figures 6 and 7, to remove the temporary bonding structure 1, exposing the front surface of the first electronic component. In this embodiment, the IDT 22 and a portion of the filter chip pads 23 on the front surface of the filter chip 2 are exposed, and the non-filter chip pads 32 on the front surface of the non-filter chip 3 and the passive component pads 42 on the front surface of the passive component 4 are exposed.

[0092] Execute sub-step S15 , referring to FIG. 8 , to form an isolation layer 6 on the front surface of the first electronic component. The isolation layer 6 , the retaining wall 24 and the front surface of the filter chip 2 constitute a cavity 25 .

[0093] In this embodiment, the isolation layer 6 may be made of a dry film material or photoresist with exposure properties, or thinned glass or silicon material with specific area openings. For example, the thickness of the isolation layer 6 is not less than 3 μm, but is not limited thereto.

[0094] The isolation layer 6 has an opening corresponding to the opening of the retaining wall 24 to expose part of the filter chip pad 23. In one embodiment of the present invention, please refer to FIG46 , the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the filter chip 2 (only the filter chip substrate 21 and the filter chip pad 23 are shown in the figure) is smaller than the cross-sectional area on the side away from the filter chip 2, that is, the opening of the isolation layer 6 is a structure that is wide at the top and narrow at the bottom to facilitate the formation of the subsequent redistribution layer. In another embodiment of the present invention, please refer to FIG8 , the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the filter chip 2 is equal to the cross-sectional area on the side away from the filter chip 2.

[0095] In one embodiment of the present invention, the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the filter chip 2 is greater than or equal to the cross-sectional area of ​​the opening of the retaining wall 24 at the corresponding position on the side away from the filter chip 2, so as to completely expose the filter chip pad 23 exposed by the retaining wall 24.

[0096] Continuing with reference to FIG8 , the isolation layer 6 has an opening to expose at least a portion of the non-filter chip pad 32. In one embodiment of the present invention, the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the non-filter chip 3 is smaller than the cross-sectional area on the side away from the non-filter chip 3, that is, the opening of the isolation layer 6 has a structure that is wide at the top and narrow at the bottom to facilitate the subsequent formation of the redistribution layer. In another embodiment of the present invention, the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the non-filter chip 3 may also be equal to the cross-sectional area on the side away from the non-filter chip 3.

[0097] Continuing with FIG8 , the isolation layer 6 has an opening to expose at least a portion of the passive component pad 42. In one embodiment of the present invention, the cross-sectional area of ​​the opening of the isolation layer 6 on the side proximal to the passive component 4 is smaller than the cross-sectional area on the side distal to the passive component 4. That is, the opening of the isolation layer 6 has a structure that is wider at the top and narrower at the bottom to facilitate the subsequent formation of a redistribution layer. In another embodiment of the present invention, the cross-sectional area of ​​the opening of the isolation layer 6 on the side proximal to the passive component 4 may also be equal to the cross-sectional area on the side distal to the passive component 4.

[0098] In step S2 , referring to FIG. 9 , at least one redistribution layer 7 is formed on the intermediate plastic package structure, and the redistribution layer 7 is electrically connected to the front surface of the first electronic component.

[0099] The redistribution layer 7 may include multiple metal wiring layers 71 and a dielectric layer 72 separating the multiple metal wiring layers 71. The metal wiring layer 71 covers the filter chip pads 23 exposed by the openings in the isolation layer 6 and the openings in the retaining wall 24, thereby electrically connecting to the filter chip pads 23. The metal wiring layer 71 also covers the non-filter chip pads 32 and the passive component pads 42 exposed by the openings in the isolation layer 6, thereby electrically connecting to the non-filter chip pads 32 and the passive component pads 42, respectively. The metal wiring layer 71 may be made of a metal such as copper or aluminum. A Ti / Cu (titanium / copper) or TiW / Cu (titanium tungsten / copper) seed layer may be formed on the copper or aluminum base. The metal wiring layer 71 may be formed by electroplating and etching. In addition to connecting the pads of each chip for signal extraction and grounding, the metal wiring layer 71 also includes matching circuit patterns to ensure the module's electrical performance. The dielectric layer 72 may be a dry film material or photoresist with exposure properties, but is not limited thereto.

[0100] In this embodiment, multiple layers of redistribution layers 7 can be formed, and the metal wiring layers 71 in the multiple layers of redistribution layers 7 are electrically connected. FIG9 shows only two layers of redistribution layers 7, but the present invention is not limited thereto. The thickness of each metal wiring layer 71 in the multiple layers of redistribution layers 7 can be the same or different, and the thickness of each dielectric layer 72 in the multiple layers of redistribution layers 7 can be the same or different.

[0101] In step S3 , referring to FIG. 10 , a first pad 8 is formed on the redistribution layer 7 , and the first pad 8 is electrically connected to the redistribution layer 7 .

[0102] The material of the first pad 8 includes, but is not limited to, copper, and the surface of the first pad 8 may be treated to prevent oxidation. The first pad 8 may be formed by electroplating and etching, and the first pad 8 contacts the metal wiring layer 71 in the redistribution layer 7 to achieve electrical connection.

[0103] In one embodiment of the present invention, a first bump 9 may be formed on the first pad 8. The first bump 9 may be a copper pillar or a solder ball.

[0104] In one embodiment of the present invention, in order to prevent short circuit during subsequent welding, a solder resist layer 10 can also be formed on the redistribution layer 7. The solder resist layer 10 is a material that is not wettable with tin. The solder resist layer 10 has an opening at the first solder pad 8 or the first bump 9 to expose the first solder pad 8 or the first bump 9.

[0105] It can then be cut into individual modules and packaged to form a single-sided RF module.

[0106] The manufacturing method of the RF module provided in this embodiment adopts a combination of WLP filter manufacturing and fan-out packaging to realize the RF module. The filter cavity and module packaging are completed at the same time, which can effectively reduce the complexity of RF front-end module manufacturing; at the same time, the filter chip completes the entire packaging process in a single chip method, thereby greatly reducing the high fragmentation rate of the filter wafer packaging; secondly, at least one layer of redistribution layer is used to replace the traditional substrate to provide interconnection, which greatly improves the interconnection density while reducing the thickness; in addition, the filter cavity will not be subjected to injection molding pressure during the entire packaging process, eliminating the cavity collapse caused by the secondary plastic packaging process. At the same time, the manufacturing method described in the present invention can realize a smaller three-dimensional RF front-end module, which can obtain a wider range of applications.

[0107] Example 2

[0108] Compared with implementation one, the difference of this embodiment is that: when the first electronic component includes a filter chip 2, a non-filter chip 3 and a passive component 4, and the passive component pad 42 is located on the front of the passive component 4, or when the first electronic component includes a filter chip 2 and a non-filter chip 3, after the front side of the first electronic component is mounted face down on the temporary bonding structure 1, before the first plastic packaging layer 51 is formed, it also includes: forming a shielding layer 13, and the shielding layer 13 at least covers the back side, side wall and part of the temporary bonding structure 1 of the first electronic component to increase electromagnetic shielding.

[0109] In this embodiment, the first electronic component including the filter chip 2 and the non-filter chip 3 is taken as an example for description.

[0110] Figures 11 to 19 are schematic diagrams of the structures of each step of the method for manufacturing the radio frequency module provided in the second embodiment of the present invention. Please refer to Figure 11. After the filter chip 2 and the non-filter chip 3 are mounted face down on the temporary bonding structure 1, a shielding layer 13 is formed. The shielding layer 13 covers the back and side walls of the filter chip 2, the outer side walls of the retaining wall 24, the back and side walls of the passive component 4, and part of the temporary bonding structure 1 (specifically the bonding layer 12 in this embodiment). The outer side wall of the retaining wall 24 refers to the side wall of the retaining wall 24 facing the outside of the filter chip 2, or refers to the side wall of the retaining wall 24 away from the side of the interdigital transducer 22.

[0111] The shielding layer 13 is made of metal, such as a single metal layer or a multi-layer metal composite layer such as copper or nickel. The shielding layer 13 can be formed by electroplating or sputtering. The thickness of the shielding layer 13 can be greater than or equal to 1 μm, but is not limited thereto.

[0112] Then, referring to FIG. 12 , a first plastic encapsulation layer 51 is formed on the temporary bonding structure 1 , and the first plastic encapsulation layer 51 covers the shielding layer 13 .

[0113] Next, the temporary bonding structure 1 is removed, exposing the front surface of the first electronic component. Figure 13 is a schematic diagram of the structure after the temporary bonding structure 1 is removed, and Figure 14 is a cross-sectional view of Figure 13 taken along line AB. Referring to Figures 13 and 14 , the shielding layer 13 surrounds the back and side walls of the filter chip 2, the outer sidewalls of the barrier layer 24, the back and side walls of the non-filter chip 3, and covers the first plastic encapsulation layer 51 between adjacent chips.

[0114] In one embodiment of the present invention, after removing the temporary bonding structure 1, a portion of the shielding layer 13 may also be removed to expose a portion of the first plastic encapsulation layer 51. Figure 15 is a schematic diagram of the structure after partially removing the shielding layer, and Figure 16 is a cross-sectional view of Figure 15 taken along line AB. Referring to Figures 15 and 16, removing a portion of the shielding layer 13 to expose the first plastic encapsulation layer 51 facilitates improving the bonding strength between the subsequently formed redistribution layer and the intermediate plastic encapsulation structure, thereby increasing module reliability.

[0115] Next, please refer to Figure 17, an isolation layer 6 is formed on the front of the filter chip 2 and the front of the non-filter 3, the isolation layer 6, the retaining wall 24 and the front of the filter chip 2 constitute a cavity 25, the isolation layer 6 covers part of the front of the non-filter chip 3 and exposes at least part of the non-filter chip pad 32, thereby forming an intermediate plastic packaging structure.

[0116] Then, referring to FIG18 , at least one redistribution layer 7 is formed on the intermediate plastic package structure. The metal wiring layer 71 in the redistribution layer 7 is electrically connected to the filter chip pad 23 and the non-filter chip pad 32. A dielectric layer 72 is used to isolate the metal wiring layer 71. Then, referring to FIG19 , a first pad 8 is formed on the redistribution layer 7. The first pad 8 is electrically connected to the redistribution layer 7. A first bump 9 may also be formed on the first pad 8, and a solder resist layer 10 is formed on the redistribution layer 7 to expose the first pad 8 and the first bump 9.

[0117] Example 3

[0118] Compared with the first embodiment, the present embodiment is different in that the method of forming the intermediate plastic packaging structure is different.

[0119] Figures 20 to 23 are schematic diagrams of the various steps of the method for manufacturing a radio frequency module provided in Example 3 of the present invention. First, similar to Example 1, a first electronic component wafer is manufactured, wherein the first electronic component wafer includes a filter wafer and a non-filter wafer and / or a passive component. A retaining wall is formed on the filter wafer, and the first electronic component wafer is divided into individual first electronic components.

[0120] In this embodiment, the first electronic component is still described as including the filter chip 2, the non-filter chip 3, and the passive component 4. A filter wafer is manufactured, a retaining wall is formed on the filter wafer, and then the filter wafer is thinned and divided into individual filter chips, forming the structure shown in Figure 2. Simultaneously, a non-filter wafer is manufactured, thinned, and divided into individual non-filter chips, forming the structure shown in Figure 3. Simultaneously, passive components are manufactured and divided into individual passive components, forming the structure shown in Figure 4.

[0121] Then, referring to FIG20 , a temporary bonding structure 1 is provided, and an isolation layer 6 is formed on the temporary bonding structure 1 corresponding to the retaining wall 24. This step can be performed simultaneously with the previous step. The temporary bonding structure 1 includes a carrier 11 and a bonding layer 12 formed on the carrier 11, and the isolation layer 6 is formed on the bonding layer 12.

[0122] Referring to Figure 21 , the front surface of the first electronic component is mounted face-down on the temporary bonding structure 1. The isolation layer 6, the retaining wall 24, and the front surface of the filter chip 2 form a cavity 25. In this embodiment, the filter chip 2, the non-filter chip 3, and the passive component 4 are mounted face-down on the temporary bonding structure 1. The isolation layer 6, the retaining wall 24, and the filter chip substrate 21 form a cavity 25.

[0123] Next, please refer to Figure 22, and form a first plastic encapsulation layer 51 on the temporary bonding structure 1. The first plastic encapsulation layer 51 covers the back and side walls of the first electronic component, the outer wall of the retaining wall 24 and part of the temporary bonding structure 1 (specifically the bonding layer 12).

[0124] Please refer to FIG. 22 and FIG. 23 , the temporary bonding structure 1 is removed to expose the front surface of the first electronic component, and finally an intermediate plastic packaging structure is formed.

[0125] In this embodiment, retaining walls 24 are first formed on the filter wafer, and then the filter wafer is divided into individual filter chips 2, and an isolation layer 6 is simultaneously formed on the temporary bonding structure 1. Compared with the first embodiment, the retaining walls 24 and the isolation layer 6 can be fabricated simultaneously, thereby saving process time.

[0126] Example 4

[0127] Compared with Example 3, the difference of this embodiment is that: when the first electronic component includes a filter chip 2, a non-filter chip 3 and a passive component 4, and the passive component pad 42 is located on the front of the passive component 4, or when the first electronic component includes a filter chip 2 and a non-filter chip 3, after the front side of the first electronic component is mounted face down on the temporary bonding structure 1, before the first plastic packaging layer 51 is formed, it also includes: forming a shielding layer 13, and the shielding layer 13 at least covers the back side, side wall and part of the temporary bonding structure 1 of the first electronic component to increase electromagnetic shielding.

[0128] In this embodiment, the first electronic component including the filter chip 2 and the non-filter chip 3 is taken as an example for description.

[0129] Figures 24 to 26 are schematic structural diagrams of each step of the method for manufacturing the radio frequency module provided in the fourth embodiment of the present invention. Referring to Figure 24, after the filter chip 2 and the front side of the non-filter chip 3 are mounted face down on the temporary bonding structure 1, a shielding layer 13 is formed, and the shielding layer 13 covers the back and side walls of the filter chip 2, the outer side walls of the retaining wall 24, the back and side walls of the non-filter chip 3, and part of the temporary bonding structure 1 (specifically the bonding layer 12 in this embodiment). In this embodiment, the shielding layer 13 also covers the outer side wall of the isolation layer 6, and the outer side wall of the isolation layer 6 refers to the side wall of the isolation layer 6 corresponding to the filter chip 2 facing the outside of the filter chip 2, or refers to the side wall of the isolation layer 6 away from the side of the interdigital transducer 22.

[0130] Then, referring to FIG. 25 , a first plastic encapsulation layer 51 is formed on the temporary bonding structure 1 , and the first plastic encapsulation layer 51 covers the shielding layer 13 .

[0131] Next, referring to FIG. 25 and FIG. 26 , the temporary bonding structure 1 is removed to expose the front surface of the first electronic component, that is, the front surface of the filter chip 2 and the front surface of the non-filter row 3 , thereby forming the intermediate plastic packaging structure.

[0132] In one embodiment of the present invention, after removing the temporary bonding structure 1, part of the shielding layer 13 can also be removed to expose part of the first plastic packaging layer 51, which is beneficial to enhance the bonding strength between the subsequently formed redistribution layer and the intermediate plastic packaging structure, thereby increasing the module reliability.

[0133] Example 5

[0134] Compared with the above embodiments, the difference of this embodiment is that: based on any of the above embodiments, this embodiment can be based on any of the above embodiments from Embodiment 1 to Embodiment 4, after forming the first solder pad 8, a second electronic component with a second bump and a first bump are formed on the first solder pad; then a second plastic encapsulation layer is formed, and the second plastic encapsulation layer covers the second electronic component, the first bump and part of the redistribution layer; then part of the second plastic encapsulation layer is removed to expose the second electronic component and the first bump.

[0135] This embodiment is described based on the structure shown in FIG9 formed in the first embodiment.

[0136] Figures 27 to 30 are schematic structural diagrams of each step of the method for manufacturing the radio frequency module provided in Example 5 of the present invention. Referring to Figure 27, a second electronic component 14 with a second bump 142 and a first bump 9 are respectively formed on the first pad 8. The second electronic component 14 includes a non-filter chip and / or a passive component, and the second electronic component 14 includes a second electronic component substrate 141 and a second bump 142 formed on the front of the second electronic component substrate 141. In this embodiment, the second electronic component 14 is a non-filter chip, and the non-filter chip includes a non-filter chip substrate and a second bump formed on the front of the non-filter chip. In this embodiment, the first bump 9 is a solder ball, such as a tin ball.

[0137] For example, the first bump 9 and the second bump 142 can be soldered to the first pad 8 using a soldering method. For example, the first bump 9 is first soldered to the first pad 8, and then the second bump 142 on the second electronic component 14 is soldered to the first pad 8. Of course, the first bump 9 and the second bump 142 are soldered to different first pads 8. Next, high-temperature reflow is performed to secure the first bump 9 and the second bump 142 to the first pad 8.

[0138] In one embodiment of the present invention, a filling glue (not shown) is provided between the front surface of the second electronic component 14 (i.e., the side close to the second bump 142) and the corresponding redistribution layer 7. The filling glue surrounds the second bump 142 to prevent the subsequent second plastic packaging layer from being unable to fill this area.

[0139] 28 , a second plastic layer 52 is formed, which covers the second electronic component 14, the first bumps 9, and a portion of the redistribution layer 7. The second plastic layer 52 is a thermosetting resin material containing inorganic fillers.

[0140] Next, referring to FIG. 29 , a portion of the second plastic encapsulation layer 52 is removed until the second electronic component 14 and the first bump 9 are exposed. In this embodiment, grinding can be used to ensure that the first bump 9 is exposed on the surface of the second plastic encapsulation layer 52. Furthermore, after the portion of the second plastic encapsulation layer 52 is removed, the upper portion of the first bump 9 is ground away, and the first bump 9 no longer has a solder ball shape, but has a flat surface.

[0141] Then, referring to FIG. 30 , the second plastic encapsulation layer 52 around the first bumps 9 is removed, and the first bumps 9 are reflowed so that the surface of the first bumps 9 is higher than the surface of the second plastic encapsulation layer 52. In other words, the reflow causes the tops of the first bumps 9 to form an outwardly convex arc shape and be higher than the surface of the second plastic encapsulation layer 52.

[0142] It can then be cut into single modules and packaged to form a double-sided RF module.

[0143] Example 6

[0144] Compared with the fifth embodiment, the present embodiment is different in that the subsequent manufacturing is based on the structure shown in FIG18 formed in the second embodiment.

[0145] Figures 31 to 34 are schematic diagrams of the various steps of the method for manufacturing a radio frequency module provided in Example 6 of the present invention. Referring to Figure 31 , a second electronic component 14 having a second bump 142 and a first bump 9 are formed on the first pad 8, respectively. In this embodiment, the second electronic component 14 is a non-filter chip, comprising a non-filter chip substrate and a second bump formed on the front surface of the non-filter chip. In this embodiment, the first bump 9 is a solder ball, such as a tin ball.

[0146] Then, referring to FIG. 32 , a second plastic encapsulation layer 52 is formed. The second plastic encapsulation layer 52 covers the second electronic component 14 , the first bumps 9 and a portion of the redistribution layer 7 .

[0147] Next, referring to FIG. 33 , a portion of the second plastic layer 52 is removed until the second electronic component 14 and the first bumps 9 are exposed.

[0148] Then, referring to FIG. 34 , the second plastic encapsulation layer 52 around the first bumps 9 is removed, and the first bumps 9 are reflowed so that the surface of the first bumps 9 is higher than the surface of the second plastic encapsulation layer 52. In other words, the reflow causes the tops of the first bumps 9 to form an outwardly convex arc shape and be higher than the surface of the second plastic encapsulation layer 52.

[0149] Example 7

[0150] Compared with the fifth embodiment, the present embodiment is different in that the first protrusions 9 are cylindrical.

[0151] This embodiment can be based on any of the above embodiments one to four, and after forming the first solder pad 8, a second electronic component with a second bump and a first bump are formed on the first solder pad; then a second plastic layer is formed, and the second plastic layer covers the second electronic component, the first bump and part of the redistribution layer; then part of the second plastic layer is removed until the second electronic component and the first bump are exposed.

[0152] This embodiment is still described based on the structure shown in FIG9 formed in the first embodiment.

[0153] Figures 35 to 39 are schematic structural diagrams of the steps of the method for manufacturing the radio frequency module provided in Example 7 of the present invention. Referring to Figure 35 , a first bump 9 is formed on a portion of the first pad 8. In this embodiment, the first bump 9 is a columnar body, such as a tin column, a copper column, or a nickel column. For example, the tin column, copper column, or nickel column can be formed by electroplating, or the copper column can be formed by welding.

[0154] Referring to FIG. 36 , a second electronic component 14 with second bumps 142 is formed on another portion of the first pads 8. The second electronic component 14 includes a non-filter chip and / or a passive component. The second electronic component 14 includes a second electronic component substrate 141 and second bumps 142 formed on the front surface of the second electronic component substrate 141. In this embodiment, the second electronic component 14 is a non-filter chip, comprising a non-filter chip substrate and second bumps formed on the front surface of the non-filter chip.

[0155] The second electronic component 14 with the second bump 142 is formed on another portion of the first pad 8 by electroplating. When the first bump 9 is also formed by electroplating, the first bump 9 and the second bump 142 can be reflow soldered simultaneously.

[0156] In one embodiment of the present invention, a filling glue (not shown) is provided between the front surface of the second electronic component 14 (i.e., the side close to the second bump 142) and the corresponding redistribution layer 7. The filling glue surrounds the second bump 142 to prevent the subsequent second plastic packaging layer from being unable to fill this area.

[0157] 37 , a second plastic layer 52 is formed, which covers the second electronic component 14, the first bumps 9, and a portion of the redistribution layer 7. The second plastic layer 52 is a thermosetting resin material containing inorganic fillers.

[0158] 38 , a portion of the second plastic layer 52 is removed until the second electronic component 14 and the first bumps 9 are exposed. In this embodiment, a grinding method can be used to ensure that the first bumps 9 are exposed on the surface of the second plastic layer 52 .

[0159] Then, referring to FIG. 39 , a second pad 15 is formed on the upper surface of the first bump 9 , and the second pad 15 is electrically connected to the first bump 9 .

[0160] Example 8

[0161] Compared with the seventh embodiment, the present embodiment is different in that the subsequent manufacturing is based on the structure shown in FIG18 formed in the second embodiment.

[0162] Figures 40 to 44 are schematic structural diagrams of the steps of the method for manufacturing a radio frequency module provided in Example 8 of the present invention. Referring to Figure 40 , a first bump 9 is formed on the first solder pad 8. In this embodiment, the first bump 9 is a columnar body, such as a tin column, a copper column, or a nickel column. For example, the tin column, copper column, or nickel column can be formed by electroplating, or the copper column can be formed by welding.

[0163] 41 , a second electronic component 14 with second bumps 142 is formed on another portion of the first pads 8. The second electronic component 14 and the first bumps 9 are formed on different first pads 8.

[0164] The second electronic component 14 with the second bump 142 is formed on another portion of the first pad 8 by electroplating. When the first bump 9 is also formed by electroplating, the first bump 9 and the second bump 142 can be reflow soldered simultaneously.

[0165] Then, referring to FIG. 42 , a second plastic encapsulation layer 52 is formed. The second plastic encapsulation layer 52 covers the second electronic component 14 , the first bumps 9 and a portion of the redistribution layer 7 .

[0166] Next, referring to FIG. 43 , a portion of the second plastic layer 52 is removed until the second electronic component 14 and the first bumps 9 are exposed.

[0167] Then, referring to FIG. 44 , a second pad 15 is formed on the upper surface of the first bump 9 , and the second pad 15 is electrically connected to the first bump 9 .

[0168] It should be noted that the embodiments in this specification are described in a progressive manner, and the manufacturing methods described later focus on the differences from the methods described previously, and the similarities and similarities between the embodiments can be referred to each other.

[0169] Correspondingly, the present invention also provides a radio frequency module, which can be manufactured using the method for manufacturing the radio frequency module described in any of the above embodiments.

[0170] Referring to FIG. 10 , the following describes a radio frequency module manufactured by the method for manufacturing the radio frequency module described in Example 1 as an example. The radio frequency module includes:

[0171] An intermediate plastic encapsulation structure, comprising: a first electronic component, comprising a filter chip 2, a non-filter chip 3, and a passive component 4; a first plastic encapsulation layer 51 covering at least the back and side walls of the first electronic component; retaining walls 24 located on both sides of the front of the filter chip 2; an isolation layer 6 covering the retaining walls 24 and forming a cavity 25 with the retaining walls 24 and the front of the filter chip 2, the isolation layer 6 also covering at least part of the front of the non-filter chip 3 and the passive component 4;

[0172] at least one redistribution layer 7 located on the intermediate plastic package structure, wherein the redistribution layer 7 is electrically connected to the front surface of the first electronic component; and

[0173] A first pad 8 is located on the redistribution layer 7 , and the first pad 8 is electrically connected to the redistribution layer 7 .

[0174] In this embodiment, an IDT 22 and filter chip pads 23 located on both sides of the IDT 22 are formed on the front of the filter chip 2; the IDT 22 is located in the cavity 25, and the retaining wall 24 and the isolation layer 6 both have openings to expose at least part of the filter chip pad 23, and the redistribution layer 7 is electrically connected to the filter chip pad 23.

[0175] In one embodiment of the present invention, the thickness of the retaining wall 24 is greater than the sum of the thickness of the IDT 22 and the thickness of the filter chip pad 23 , so as to ensure the height of the cavity 25 .

[0176] In one embodiment of the present invention, as shown in FIG45 , the cross-sectional area of ​​the opening of the retaining wall 24 on the side close to the filter chip 2 (only the filter chip substrate 21 and the filter chip pad 23 are shown in the figure) is smaller than the cross-sectional area on the side away from the filter chip 2, that is, the opening has a structure that is wider at the top and narrower at the bottom, so as to facilitate the electrical connection between the redistribution layer 7 and the filter chip pad 23. In another embodiment of the present invention, as shown in FIG10 , the cross-sectional area of ​​the opening of the retaining wall 24 on the side close to the filter chip 2 is equal to the cross-sectional area on the side away from the filter chip 2.

[0177] In one embodiment of the present invention, as shown in FIG46 , the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the filter chip 2 (only the filter chip substrate 21 and the filter chip pad 23 are shown in the figure) is smaller than the cross-sectional area on the side away from the filter chip 2. That is, the opening of the isolation layer 6 has a structure that is wider at the top and narrower at the bottom to facilitate electrical connection between the redistribution layer 7 and the filter chip pad 23. In another embodiment of the present invention, as shown in FIG10 , the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the filter chip 2 is equal to the cross-sectional area on the side away from the filter chip 2.

[0178] In one embodiment of the present invention, the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the filter chip 2 is greater than or equal to the cross-sectional area of ​​the opening of the retaining wall 24 at the corresponding position on the side away from the filter chip 2, so as to completely expose the filter chip pad 23 exposed by the retaining wall 24.

[0179] A non-filter chip pad 32 is formed on the front of the non-filter chip 3, and the isolation layer 6 has an opening to expose at least a portion of the non-filter chip pad 32; a passive component pad 42 is formed on the front of the passive component 4, and the isolation layer 6 has an opening to expose at least a portion of the passive component pad 42.

[0180] In one embodiment of the present invention, the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the non-filter chip 3 is smaller than or equal to the cross-sectional area on the side away from the non-filter chip 3; the cross-sectional area of ​​the opening of the isolation layer 6 on the side close to the passive component 4 is smaller than or equal to the cross-sectional area on the side away from the passive component 4.

[0181] In addition, in one embodiment of the present invention, when the first electronic component includes a filter chip 2 and a non-filter chip 3 (please refer to FIG19 ), or when the first electronic component includes a filter chip 2, a non-filter chip 3 and a passive component 4, and the passive component pad 42 is located on the front of the passive component 4 (not shown), the RF module further includes a shielding layer 13, and the shielding layer 13 at least covers the back and side walls of the filter chip 2 and the back and side walls of the non-filter chip 3 to increase electromagnetic shielding. In this embodiment, the shielding layer 13 can also expose a portion of the first plastic packaging layer 51 to ensure the bonding strength between the intermediate plastic packaging structure and the redistribution layer 7, thereby increasing module reliability.

[0182] In addition, in one embodiment of the present invention, referring to FIG. 30 or FIG. 44 , the RF module further includes: a first bump 9 located on the first solder pad 8 and a second electronic component 14 having a second bump 142; and a second plastic encapsulation layer 52, the second plastic encapsulation layer 52 covering the sidewalls of the second electronic component 14 and the first bump 9. Referring to FIG. 30 , the first bump 9 is a solder ball, and the surface of the first bump 9 is higher than the surface of the second plastic encapsulation layer 52. Referring to FIG. 44 , the first bump 9 is a columnar shape, with a second solder pad 15 formed on the top surface of the first bump 9.

[0183] To sum up, in the RF module and its manufacturing method provided by the present invention, an intermediate plastic packaging structure is first provided, and the intermediate plastic packaging structure includes: a first electronic component, the first electronic component includes a filter chip and a non-filter chip or / and a passive component; a first plastic packaging layer that at least covers the back and side walls of the first electronic component; a retaining wall located on both sides of the front of the filter chip; an isolation layer that covers the retaining wall and forms a cavity with the retaining wall and the front of the filter chip, and the isolation layer also covers at least part of the front of the non-filter chip or / and the passive component; then at least one redistribution layer is formed, and the redistribution layer is electrically connected to the front of the first electronic component; then a first soldering pad is formed, and the first soldering pad is electrically connected to the redistribution layer. The present invention adopts a combination of WLP filter production and fan-out packaging to realize the radio frequency module. The filter cavity and module packaging are completed at the same time, which can effectively reduce the complexity of radio frequency front-end module production. At the same time, the filter chip completes the entire packaging process in a single chip method, thereby greatly reducing the high fragmentation rate of the filter wafer packaging. Secondly, at least one layer of redistribution layer is used to replace the traditional substrate to provide interconnection, which greatly improves the interconnection density while reducing the thickness. In addition, the filter cavity will not be subjected to injection molding pressure during the entire packaging process, eliminating the cavity collapse caused by the secondary plastic packaging process. At the same time, the production method described in the present invention can realize a smaller three-dimensional radio frequency front-end module, which can obtain a wider range of applications.

[0184] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for manufacturing a radio frequency module, characterized in that: The following steps are involved: An intermediate plastic packaging structure is provided, comprising: a first electronic component, the first electronic component comprising a filter chip and a non-filter chip and / or a passive component; a first plastic packaging layer covering at least the back surface and sidewalls of the first electronic component; retaining walls located on both sides of the front surface of the filter chip; an isolation layer covering the retaining walls and forming a cavity with the retaining walls and the front surface of the filter chip, the isolation layer also covering at least a portion of the front surface of the non-filter chip and / or the passive component; forming at least one redistribution layer on the intermediate plastic package structure, wherein the redistribution layer is electrically connected to the front surface of the first electronic component; and A first pad is formed on the redistribution layer, and the first pad is electrically connected to the redistribution layer.

2. The method for manufacturing a radio frequency module according to claim 1, wherein: The method for providing an intermediate plastic packaging structure includes: Manufacturing a first electronic component wafer, wherein the first electronic component wafer includes a filter wafer and a non-filter wafer and / or a passive component, forming a retaining wall on the filter wafer, and dividing the first electronic component wafer into individual first electronic components; Providing a temporary bonding structure, and mounting the first electronic component with its front side facing downward on the temporary bonding structure; forming a first plastic encapsulation layer on the temporary bonding structure, wherein the first plastic encapsulation layer covers the back surface and sidewalls of the first electronic component, the outer sidewalls of the retaining wall, and a portion of the temporary bonding structure; removing the temporary bonding structure to expose the front surface of the first electronic component; and An isolation layer is formed on the front surface of the first electronic component, and the isolation layer, the retaining wall and the front surface of the filter chip constitute a cavity.

3. The method for manufacturing a radio frequency module according to claim 1, wherein: The method for providing an intermediate plastic packaging structure includes: Manufacturing a first electronic component wafer, wherein the first electronic component wafer includes a filter wafer and a non-filter wafer and / or a passive component, forming a retaining wall on the filter wafer, and dividing the first electronic component wafer into individual first electronic components; providing a temporary bonding structure, and forming an isolation layer corresponding to the retaining wall on the temporary bonding structure; Mounting the first electronic component with its front side facing downward on the temporary bonding structure, wherein the isolation layer, the retaining wall and the front side of the filter chip form a cavity; forming a first plastic encapsulation layer on the temporary bonding structure, wherein the first plastic encapsulation layer covers the back surface and side walls of the first electronic component, the outer side walls of the retaining wall, and a portion of the temporary bonding structure; and The temporary bonding structure is removed to expose the front surface of the first electronic component.

4. The method for manufacturing a radio frequency module according to claim 2 or 3, wherein: When the first electronic component includes a filter chip and a non-filter chip, or when the first electronic component includes a filter chip, a non-filter chip and a passive component, and the passive component pad is located on the front side of the passive component, after mounting the first electronic component with the front side facing downward on the temporary bonding structure and before forming the first plastic encapsulation layer, the method further includes: forming a shielding layer, wherein the shielding layer covers at least the back side, side wall and part of the temporary bonding structure of the first electronic component; After removing the temporary bonding structure, the method further includes: removing a portion of the shielding layer to expose a portion of the first plastic packaging layer.

5. The method for manufacturing a radio frequency module according to claim 1, wherein: After forming the first pad, the manufacturing method further includes: forming a second electronic component with a second bump and the first bump on the first pad respectively; forming a second plastic encapsulation layer, wherein the second plastic encapsulation layer covers the second electronic component, the first bump, and a portion of the redistribution layer; and A portion of the second plastic packaging layer is removed until the second electronic component and the first bump are exposed.

6. The method for manufacturing a radio frequency module according to claim 5, wherein: The second electronic component includes a non-filter chip and / or a passive component.

7. The method for manufacturing a radio frequency module according to claim 5, wherein: The first bump is a solder ball; After removing part of the second plastic sealing layer, the method further includes: removing a portion of the second plastic encapsulation layer around the first bump; as well as The first bumps are reflowed so that the surfaces of the first bumps are higher than the surface of the second plastic encapsulation layer.

8. The method for manufacturing a radio frequency module according to claim 5, wherein: The first convex point is a column; after removing part of the second plastic packaging layer, the method further includes: forming a second solder pad on the upper surface of the first convex point.

9. A radio frequency module, characterized in that: include: An intermediate plastic encapsulation structure, the intermediate plastic encapsulation structure comprising: a first electronic component, the first electronic component comprising a filter chip and a non-filter chip and / or a passive component; a first plastic encapsulation layer covering at least the back surface and side walls of the first electronic component; retaining walls located on both sides of the front surface of the filter chip; an isolation layer covering the retaining walls and forming a cavity with the retaining walls and the front surface of the filter chip, the isolation layer also covering at least a portion of the front surface of the non-filter chip and / or the passive component; at least one redistribution layer located on the intermediate plastic package structure, the redistribution layer being electrically connected to the front surface of the first electronic component; and A first pad is located on the redistribution layer, and the first pad is electrically connected to the redistribution layer.

10. The radio frequency module according to claim 9, characterized in that: When the first electronic component includes a filter chip and a non-filter chip, or when the first electronic component includes a filter chip, a non-filter chip and a passive component, and the passive component pad is located on the front of the passive component, the RF module also includes a shielding layer, and the shielding layer covers at least the back and side walls of the first electronic component.

11. The radio frequency module according to claim 9, wherein: The radio frequency module also includes: a first bump located on the first pad and a second electronic component having a second bump; and A second plastic encapsulation layer covers the second electronic component and side walls of the first bump.

12. The radio frequency module according to claim 11, wherein: The second electronic component includes a non-filter chip and / or a passive component.

13. The radio frequency module according to claim 11, wherein: The first bump is a solder ball, and the surface of the first bump is higher than the surface of the second plastic packaging layer.

14. The radio frequency module according to claim 11, wherein: The first bump is in the form of a column; a second pad is formed on the top surface of the first bump.

15. The radio frequency module according to claim 9, wherein: An interdigital transducer and filter chip pads located on both sides of the interdigital transducer are formed on the front of the filter chip; the interdigital transducer is located in the cavity, the retaining wall and the isolation layer both have openings to expose at least part of the filter chip pads, and the redistribution layer is electrically connected to the filter chip pads.

16. The radio frequency module according to claim 15, characterized in that: The thickness of the retaining wall is greater than the sum of the thickness of the interdigital transducer and the thickness of the pad of the filter chip.

17. The radio frequency module according to claim 15, wherein: The cross-sectional area of ​​the opening of the retaining wall on the side close to the filter chip is smaller than or equal to the cross-sectional area on the side away from the filter chip; the cross-sectional area of ​​the opening of the isolation layer on the side close to the filter chip is smaller than or equal to the cross-sectional area on the side away from the filter chip.

18. The radio frequency module according to claim 15, wherein: The cross-sectional area of ​​the opening of the isolation layer on the side close to the filter chip is greater than or equal to the cross-sectional area of ​​the opening of the retaining wall at the corresponding position on the side away from the filter chip.

19. The radio frequency module according to claim 9, wherein: A non-filter chip pad is formed on the front of the non-filter chip, and the isolation layer has an opening to expose at least a portion of the non-filter chip pad; a passive component pad is formed on the front of the passive component, and the isolation layer has an opening to expose at least a portion of the passive component pad.

20. The radio frequency module according to claim 19, wherein: The cross-sectional area of ​​the opening of the isolation layer on the side close to the non-filter chip is smaller than or equal to the cross-sectional area on the side away from the non-filter chip; the cross-sectional area of ​​the opening of the isolation layer on the side close to the passive component is smaller than or equal to the cross-sectional area on the side away from the passive component.

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