Radio frequency module preparation method and radio frequency module

Abstract

A radio frequency module preparation method and a radio frequency module. The method comprises: providing an initial chip board, wherein the initial chip board comprises a substrate (120) and a plurality of radio frequency modules fixed on the substrate (120), and each radio frequency module comprises a plurality of components (110); covering, with a layer of dry film (140), the surface of the side of the initial chip board having the radio frequency modules, so as to form a cavity between the dry film (140), the corresponding component (110) and the substrate (120); forming a first metal layer (150) on a surface of the dry film (140), and forming a plastic packaging layer (160) on the first metal layer (150); forming a second metal layer (170) on a surface of the plastic packaging layer (160), and electrically connecting the second metal layer (170) to the first metal layer (150); and cutting the initial chip board along a boundary between adjacent radio frequency modules to obtain a single radio frequency module. The method can effectively reduce the risk of short circuit of the radio frequency module, such that the electromagnetic shielding effect of the radio frequency module is more obvious, and the production efficiency of the single radio frequency module after electromagnetic shielding processing is improved.

Description

A radio frequency module preparation method and radio frequency module Technical Field

[0001] The present invention belongs to the technical field of electromagnetic shielding, and in particular relates to a method for preparing a radio frequency module and a radio frequency module. Background Art

[0002] With the development of the times, the integration requirements for RF chips are becoming increasingly higher. For transmitting RF modules, chips with different functions need to be integrated into a single chip. This can cause electromagnetic interference between chips with different functions, affecting the performance of individual chip products. Electromagnetic shielding (EMI shielding) involves placing a layer of grounded metal on the outer surface of the chip circuit to reduce EMI through metal absorption and ground conduction.

[0003] The chip electromagnetic shielding process of the existing technology cuts the chips with different functions into single chips after plastic sealing, and then sputters the metal layer on the single chip products. This method has the following defects: on the one hand, the process conversion efficiency of plastic sealing the single chips separately is extremely low, and additional conversion jigs are required, which is costly; on the other hand, when the single chip after plastic sealing is peeled off after the metal layer is sputtered, metal wire drawing will occur with the bottom of the chip, which is easy to produce metal burrs, and thus bring the risk of reliability short circuit.

[0004] Therefore, it is necessary to provide a method for preparing a radio frequency module and a radio frequency module with high production efficiency and strong reliability. Technical issues

[0005] The object of the present invention is to provide a method for preparing a radio frequency module and a radio frequency module, which can be used to batch prepare radio frequency modules with electromagnetic shielding layers, with high production efficiency and strong reliability. Technical Solutions

[0006] The technical solutions of the present invention are as follows:

[0007] A first aspect of the present invention provides a method for preparing a radio frequency module, comprising:

[0008] Providing an initial chip board, the initial chip board comprising a substrate and a plurality of radio frequency modules fixed to the substrate, the radio frequency modules comprising a plurality of components;

[0009] A dry film is covered on the surface of the initial chip board having the RF module, and a cavity is formed between the dry film, the components and the substrate;

[0010] forming a first metal layer on the surface of the dry film, and forming a plastic sealing layer on the first metal layer;

[0011] forming a second metal layer on the surface of the plastic encapsulation layer, wherein the second metal layer is electrically connected to the first metal layer;

[0012] The initial chip board is cut along the dividing line between adjacent RF modules to obtain a single RF module.

[0013] Furthermore, before forming the second metal layer on the surface of the plastic packaging layer, the method further includes: cutting the initial chip board to form a groove at a boundary line between adjacent RF modules, wherein the bottom of the groove passes through the first metal layer.

[0014] Furthermore, forming a first metal layer on the surface of the dry film specifically includes:

[0015] The first metal layer is formed by vacuum sputtering or electronic paste printing on the surface of the dry film.

[0016] Furthermore, forming a second metal layer on the surface of the plastic sealing layer specifically includes:

[0017] The second metal layer is formed by electroplating or metal vacuum sputtering on the surface of the plastic sealing layer.

[0018] Furthermore, the plurality of components include at least one filter chip and at least one non-filter chip; the first metal layer and the dry film between the non-filter chip and the substrate have a gate area;

[0019] The forming of a plastic sealing layer on the first metal layer specifically includes:

[0020] injecting epoxy resin and breaking through the gate area to fill the gaps between the non-filter chip, the substrate, and the dry film;

[0021] Continue to inject epoxy resin until it covers the first metal layer, and solidify to form a plastic sealing layer.

[0022] Furthermore, the thickness of the first metal layer is 3-5 μm.

[0023] Furthermore, the first metal layer includes at least one metal selected from the group consisting of steel, copper, aluminum, nickel, and silver.

[0024] Furthermore, providing an initial chip board includes:

[0025] Provide a substrate and multiple sets of components of the radio frequency module;

[0026] The components of each radio frequency module are respectively soldered to the corresponding areas of the substrate and cleaned.

[0027] Furthermore, the substrate has a welding area for connecting the components and a non-welding area outside the welding area, and the components of each RF module are welded to the corresponding area of ​​the substrate, including:

[0028] Coating a solder resist on the substrate to form a solder resist layer in a non-soldering area of ​​the substrate;

[0029] Metallizing the surface of the components of each radio frequency module and adding solder to form bumps in a reflow oven;

[0030] The components of each radio frequency module are reflow-soldered to the welding area of ​​the substrate.

[0031] A second aspect of the present invention provides a radio frequency module, comprising a substrate coated with a solder resist layer and a plurality of components fixed on the substrate, the radio frequency module also comprising a dry film covering the substrate and the plurality of components, a first metal layer covering the side of the dry film facing away from the substrate, a plastic encapsulation layer covering the side of the first metal layer facing away from the substrate, and a second metal layer covering the outer surface of the plastic encapsulation layer; a cavity is formed between the dry film, the components and the substrate, and the first metal layer is electrically connected to the second metal layer. Beneficial effects

[0032] The beneficial effects of the present invention are:

[0033] First, when the first metal layer is formed on the dry film surface, a cavity is formed between the dry film, components, and substrate, preventing metal wire drawing from occurring between the components and the metal layer, effectively reducing the risk of reliability short circuits in the RF module.

[0034] Second, a plastic encapsulation layer is formed on the surface of the first metal layer, and a second metal layer is formed on the surface of the plastic encapsulation layer. The first metal layer and the second metal layer are electrically connected to form a parallel effect, thereby making the electromagnetic shielding effect of the RF module more obvious;

[0035] Third, the initial chip board with multiple RF modules is cut after forming the first metal layer, the plastic sealing layer and the second metal layer on the surface, which can mass-produce single RF modules after electromagnetic shielding treatment, reduce production costs and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is a schematic diagram of the main process of a method for preparing a radio frequency module according to the present invention;

[0037] FIG2 is a schematic structural diagram of steps S100 and S200 in FIG1 after completion of each process;

[0038] FIG3 is a schematic structural diagram of step S300 in FIG1 after each process is completed;

[0039] FIG4 is a schematic structural diagram after steps S400 and S500 in FIG1 are completed;

[0040] FIG5 is a schematic diagram of the cross-sectional structure of the radio frequency module of the present invention. Modes for Carrying Out the Invention

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0042] This embodiment provides a method for preparing a radio frequency module, as shown in FIG1 , comprising the following steps:

[0043] S100, providing an initial chip board, the initial chip board including a substrate 120 and a plurality of radio frequency modules fixed to the substrate 120, the radio frequency modules including a plurality of components 110;

[0044] S200, covering the surface of the initial chip board with the RF module with a layer of dry film 140, forming a cavity between the dry film 140, the component 110 and the substrate 120;

[0045] S300 , forming a first metal layer 150 on the surface of the dry film 140 , and forming a plastic encapsulation layer 160 on the first metal layer 150 ;

[0046] S400, forming a second metal layer 170 on the surface of the plastic layer 160, wherein the second metal layer 170 is electrically connected to the first metal layer 150;

[0047] S500 , cutting the initial chip board along the dividing line between adjacent RF modules to obtain a single RF module.

[0048] Specifically, in this embodiment, as shown in FIG2 , the specific steps of step S100 are as follows:

[0049] S101, providing a substrate 120 and multiple components 110 of multiple sets of radio frequency modules;

[0050] Specifically, the substrate 120 is a carrier board for the components 110 of multiple sets of radio frequency modules, and may be a printed circuit board made of organic resin, or a glass substrate 120 or a ceramic substrate 120 .

[0051] The substrate 120 has a welding area for connecting the components 110 and a non-welding area outside the welding area. The components 110 of each RF module are welded to the corresponding area of ​​the substrate 120, specifically including:

[0052] S102, coating a solder resist on the surface of the substrate 120 to form a solder resist layer 130 on the non-soldering area of ​​the substrate 120;

[0053] Specifically, in this step, the surface of the substrate 120 is cleaned to remove dirt and other contaminants, then the surface of the substrate 120 is dried and coated with solder resist. For example, the substrate 120 is coated with a UV-curable solder resist epoxy resin. The solder resist on the surface of the substrate 120 is partially photocured to form a solder resist layer 130. Finally, the substrate 120 is immersed in a developer to remove the uncured solder resist, thereby exposing the soldering area on the surface of the substrate 120. The solder resist is used to form an insulating solder resist layer 130 on the surface of the substrate 120, covering the non-soldering area of ​​the substrate 120. The solder resist layer 130 prevents the components 110 from being soldered to the non-soldering area.

[0054] In other embodiments, the solder resist may be a UV-curable solder resist, a thermal-curable solder resist, a liquid photosensitive solder resist, or a dry film 140 solder resist.

[0055] S103, metallizing the surface of the components 110 of each RF module, and adding solder in a reflow furnace to form bumps 113;

[0056] Specifically, in this step, before metallizing the surface of the components 110 of each RF module, the surface of the components 110 is cleaned and debonded. The surface of the components 110 of each RF module can be metallized by vacuum sputtering, vacuum evaporation, or chemical plating. As an example, vacuum sputtering is used to metallize the components 110 of each RF module. Vacuum sputtering has strong step coverage and adhesion to the substrate, making it suitable for large-scale RF module manufacturing.

[0057] After the surface of the components 110 of each RF module is metallized, solder is added to the metallized part through a reflow furnace to form bumps 113. The solder bumps 113 can be formed by electroplating solder bumps 113, printing solder bumps 113, nail head solder bumps 113 or vapor deposition solder bumps 113.

[0058] The bumps 113 can be solder bumps, copper pillar bumps, or gold bumps. As an example, the bumps 113 in this embodiment are copper pillar bumps. Copper pillar bumps have higher reliability, higher interconnect density, and better electrical and thermal performance than solder bumps. During reflow soldering, the copper pillar bumps can maintain their shape in three dimensions, making the welding between the substrate 120 and each RF module more precise.

[0059] S104 , reflow soldering the components 110 of each RF module to the substrate 120 , and soldering the bumps 113 to the areas of the substrate 120 where the solder resist layer 130 is not formed;

[0060] Specifically, in this step, the components 110 of each RF module are flip-chip interconnected with the substrate 120, the side of the component 110 with the bump 113 is dipped in flux and adhered to the area of ​​the substrate 120 where the solder mask 130 is not formed, the substrate 120 after the bonding is placed in a reflow oven to melt the copper pillar bumps, and the components 110 and the substrate 120 are combined to obtain an initial chip board.

[0061] S105 , cleaning the RF module components 110 and substrate 120 after welding.

[0062] Specifically, in this step, the RF module components 110 and substrate 120 after welding are cleaned and baked by plasma to remove impurities and contaminants on the RF module components 110 and substrate 120, which is beneficial to the subsequent process.

[0063] As shown in FIG3 , step S200 : covering the surface of the initial chip board with the RF module with a layer of dry film 140 , forming a cavity between the dry film 140 , the component 110 and the substrate 120 ;

[0064] Specifically, in this embodiment, a layer of white film is covered on the surface of the initial chip board having the RF module side. The white film is used to isolate the filter chip 111 from other metal shielding layers. On the one hand, the white film plays a role in protecting the functional components of the filter chip 111. On the other hand, the white film isolates the metal shielding layer from the filter chip 111, thereby avoiding metal wire drawing from the edge of the component 110 when the vacuum sputtering coating is peeled off, thereby increasing the reliability of mass production of RF modules.

[0065] Specifically, as shown in FIG3 , in this embodiment, the specific steps of step S300 are as follows:

[0066] Forming a first metal layer 150 on the surface of the dry film 140 specifically includes:

[0067] S301: vacuum sputtering or electronic paste printing of metal on the surface of the dry film 140 to form a first metal layer 150; the first metal layer 150 includes at least one metal selected from steel, copper, aluminum, nickel or silver;

[0068] Specifically, as shown in FIG3 , in this step, vacuum sputtering is used to form the first metal layer 150. The bonding force between the first metal layer 150 and the dry film 140 is strong and not easy to fall off. The obtained first metal layer 150 has high purity and good quality. Secondly, vacuum sputtering has strong controllability and high repeatability for the film thickness of the first metal layer 150, which is conducive to mass production.

[0069] There is a large amount of electromagnetic interference and infinite radio interference between the components 110. The first metal layer 150 is used to form a metal shielding layer between the multiple components 110. Compared with the related art of sputtering each component 110 individually, forming the first metal layer 150 on the surface of the dry film 140 can, on the one hand, perform batch electromagnetic shielding for multiple sets of RF modules. On the other hand, the dry film 140 has already formed a cavity between the component 110 and the substrate 120, and the vacuum sputtering coating cannot contact the metal part of the surface of the component 110. This avoids the generation of metal wire drawing on the edge of the component 110 when the vacuum sputtering coating is peeled off, resulting in metal burrs on the edge of the component 110, and reducing the risk of reliability short circuit of the RF module.

[0070] Preferably, stainless steel and copper are selected as the target materials for vacuum sputtering the first metal layer 150. Stainless steel and copper are both sputtering target materials with high purity and low impurities, better film quality and good electrical properties.

[0071] Furthermore, the plurality of components 110 include at least one filter chip 111 and at least one non-filter chip 112. The first metal layer 150 and the dry film 140 between the non-filter chip 112 and the substrate 120 have a gate area 180. As shown in FIG3 , a plastic encapsulation layer 160 is formed on the first metal layer 150, specifically including:

[0072] S302 : Injecting epoxy resin and breaking through the gate area 180 to fill the gaps between the non-filter chip 112 , the substrate 120 and the dry film 140 ;

[0073] Specifically, as shown in Figure 3, filter chip 111 is provided with a functional device having a filtering function on one side. Filter chip 111 has surface metallization on one side of the functional device to form bumps 113. Bumps 113 connect filter chip 111 to substrate 120, forming a cavity between the functional device and substrate 120 to protect the functional device. Non-filter chip 112 can be an electronic component without a filtering function, such as a capacitor, inductor, or power amplifier. Therefore, a cavity is not required between the non-filter chip and substrate 120.

[0074] The first metal layer has a thickness of 3-5 μm. Therefore, by adjusting the injection pressure and injecting epoxy resin into the gate area 180, the corresponding first metal layer 150 and dry film 140 can be penetrated, completely filling the gaps between the non-filter chip 112, substrate 120, and dry film. The gate area 180 is a localized point on the first metal layer 150 and dry film 140.

[0075] The purpose of filling the gaps between the non-filter chip 112, the substrate 120 and the dry film 140 is to improve the stability of the flip-chip non-filter chip 112. The glue filling can disperse the stress concentrated on the non-filter chip 112, thereby enhancing the ability of the non-filter chip 112 to withstand mechanical vibrations. It can also prevent the bumps 113 from creeping, increase the strength and rigidity of the connection between the non-filter chip 112 and the substrate 120, and at the same time, protect the non-filter chip 112 from dust and moisture in the environment.

[0076] S303: Continue to inject epoxy resin until it covers the first metal layer 150 and solidify to form a plastic sealing layer 160;

[0077] Specifically, as shown in FIG3 , in one embodiment, the initial chip board is placed in a plastic encapsulation mold and completely filled with epoxy resin. The epoxy resin can form a hard protective layer through a curing reaction and has high heat resistance and chemical corrosion resistance. The plastic encapsulation layer 160 is used to protect the internal structure of the chip from the influence of the external environment, and also acts as an insulator between the first metal layer 150 and the second metal layer 170. At the same time, different from the plastic encapsulation process in the related art, the plastic encapsulation layer 160 in the present invention is injection molded and cured on the first metal layer 150, rather than directly on the surface of the component 110. This reduces the impact of the injection molding high pressure on the component 110, improves the reliability of the preparation of the RF module, and the overall injection molding can also improve the preparation efficiency of the RF module. In other embodiments, plastic encapsulation materials such as polyimide, silicone and organic glass can also be used for injection molding.

[0078] In other embodiments, the plastic sealing layer 160 may be formed by integrally laminating an epoxy resin film, which can reduce process costs and prevent damage to the first metal layer 150 caused by high injection pressure, thereby insulating and protecting the first metal layer 150.

[0079] S304 : half-cutting the initial chip board to form a groove 190 at a boundary line between adjacent RF modules, with the bottom of the groove 190 penetrating the first metal layer 150 .

[0080] As shown in Figure 3, half-cutting is a process that forms a groove by cutting into the middle of a workpiece. Preferably, the groove 190 is perpendicular to the substrate 120, and the bottom of the groove is located inside the substrate 120. In related art, half-cutting technology is used to separate chips. Compared with related art, the initial chip board uses a half-cutting process before forming the second metal layer 170. The purpose is to expose the groove wall of the groove 190 to the first metal layer 150, which facilitates the connection between the first metal layer 150 and the second metal layer 170 to form an electromagnetic shielding layer separated inside and outside, achieving a better electromagnetic shielding effect.

[0081] Specifically, in this embodiment, as shown in FIG4 , step S400 specifically includes:

[0082] S400 : Electroplating or vacuum sputtering metal on the surface of the plastic packaging layer 160 to form a second metal layer 170 . The second metal layer 170 is electrically connected to the first metal layer 150 .

[0083] Preferably, a second metal layer 170 is formed by electroplating on the surface of the plastic encapsulation layer 160. In addition to being used as an electromagnetic shielding layer, the second metal layer 170 formed by electroplating is located on the outer surface of the RF module. The outer surface of the RF module may be subject to chemical corrosion. The electroplated second metal layer 170 can protect the chip surface.

[0084] The first metal layer 150 serves as an inner shielding layer, and the second metal layer 170 serves as an outer shielding layer. The second metal layer 170 and the first metal layer 150 are connected in parallel to effectively shield electromagnetic interference of different frequencies. At the same time, the first metal layer 150 can reduce the electromagnetic radiation between the multiple components 110 of the RF module, and the second metal layer 170 can reduce the interference of the external electromagnetic field on the multiple components 110 of the RF module, making the electromagnetic shielding effect more obvious.

[0085] Optionally, the second metal layer 170 sputtered by the vacuum sputtering process includes at least one metal of steel, copper, aluminum, nickel or silver, and the material of the second metal layer 170 by the electroplating process can be any one of copper, nickel, chromium, gold, zinc or silver.

[0086] As shown in FIG4 , step 500 : cutting the initial chip board to obtain a single RF module.

[0087] Specifically, the cutting process of the half-cutting process in step S303 is continued to obtain a single RF module. This preparation method has high efficiency in preparing a single RF module.

[0088] Furthermore, in this embodiment, as shown in Figure 5, a radio frequency module is prepared by the above-mentioned preparation method, including a substrate 120 coated with a solder resist layer 130 and a plurality of components 110 fixed on the substrate 120, and the radio frequency module also includes a dry film 140 covering the substrate 120 and the plurality of components 110, a first metal layer 150 covering the side of the dry film 140 facing away from the substrate 120, a plastic sealing layer 160 covering the side of the first metal layer 150 facing away from the substrate 120, and a second metal layer 170 covering the outer surface of the plastic sealing layer 160; a cavity is formed between the dry film 140, the components 110 and the substrate 120, and the first metal layer 150 is electrically connected to the second metal layer 170.

[0089] Specifically, as shown in FIG. 5 , a radio frequency module includes a substrate 120 and a solder resist layer 130 coated on a surface of the substrate 120 . The solder resist layer 130 is provided with a plurality of first solder grooves penetrating the solder resist layer 130 .

[0090] The RF module also includes multiple components 110 electrically connected to the substrate 120. The multiple components 110 include at least one filter chip 111 and at least one non-filter chip 112. The filter chip 111 is provided with multiple first bumps 113 at intervals on the surface of one side close to the substrate 120. The multiple first bumps 113 are matched one by one with the multiple first welding grooves. Each first bump 113 is arranged in the corresponding first welding groove and is electrically connected to the substrate 120.

[0091] A plurality of second bumps 113 are spaced apart on a surface of the non-filter chip 112 on a side adjacent to the substrate 120. The solder resist layer 130 also has second solder grooves extending through the solder resist layer 130. Each second bump 113 is disposed within the second solder grooves and is electrically connected to the substrate 120. A curing material is filled between the non-filter chip 112, the second solder grooves, and the substrate 120.

[0092] The RF module also includes a dry film 140 that covers multiple components 110 and covers the surface of the solder mask layer 130. The surface of the dry film 140 is covered with a first metal layer 150. A plastic layer 160 is injection molded on the upper surface of the first metal layer 150. The side of the RF module and the surface of the plastic layer 160 are covered with a second metal layer 170. The first metal layer 150 is electrically connected to the second metal layer 170.

[0093] Optionally, the first metal layer 150 is covered on the dry film 140 by metal vacuum sputtering or electronic paste printing.

[0094] Optionally, the first metal layer 150 includes at least one metal selected from the group consisting of steel, copper, aluminum, nickel, and silver.

[0095] Optionally, the plastic packaging layer 160 is formed by injection molding epoxy resin on the first metal layer 150 or by laminating an epoxy resin film.

[0096] Optionally, the second metal layer 170 is covered on the plastic packaging layer 160 by electroplating or metal vacuum sputtering.

[0097] Compared with the RF modules in related arts, the RF module of this invention forms a cavity between the dry film 140, the component 110 and the substrate 120. The cavity can protect the component 110 of the RF module and isolate the component 110 from the first metal layer 150, thereby preventing metal wire drawing and effectively reducing the risk of reliability short circuit of the RF module.

[0098] The plastic encapsulation layer 160 between the first metal layer 150 and the second metal layer 170 acts as an insulator. The first metal layer 150 and the second metal layer 170 are electrically connected to form a parallel electromagnetic shielding layer, so that the RF module can achieve a better electromagnetic shielding effect.

[0099] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a radio frequency module, characterized in that, include: Providing an initial chip board, the initial chip board comprising a substrate and a plurality of radio frequency modules fixed to the substrate, the radio frequency modules comprising a plurality of components; A layer of dry film is covered on the surface of the initial chip board having the RF module, and a cavity is formed between the dry film, the components and the substrate; forming a first metal layer on the surface of the dry film, and forming a plastic sealing layer on the first metal layer; forming a second metal layer on the surface of the plastic encapsulation layer, wherein the second metal layer is electrically connected to the first metal layer; The initial chip board is cut along the boundary line between adjacent RF modules to obtain a single RF module.

2. The method according to claim 1, characterized in that, Before forming the second metal layer on the surface of the plastic packaging layer, the method further includes: cutting the initial chip board to form a groove at the boundary between adjacent RF modules, wherein the bottom of the groove passes through the first metal layer.

3. The method according to claim 1, characterized in that, The step of forming a first metal layer on the surface of the dry film specifically includes: The first metal layer is formed by vacuum sputtering or electronic paste printing on the surface of the dry film.

4. The method according to claim 1, characterized in that, The forming of the second metal layer on the surface of the plastic encapsulation layer specifically includes: The second metal layer is formed by electroplating or metal vacuum sputtering on the surface of the plastic packaging layer.

5. The method according to claim 1, characterized in that, The plurality of components include at least one filter chip and at least one non-filter chip; the first metal layer and the dry film between the non-filter chip and the substrate have a gate area; The step of forming a plastic sealing layer on the first metal layer specifically includes: injecting epoxy resin and breaking through the gate area to fill the gaps between the non-filter chip, the substrate and the dry film; Continue to inject epoxy resin until it covers the first metal layer, and solidify to form a plastic sealing layer.

6. The method according to claim 1, characterized in that, The thickness of the first metal layer is 3-5 μm.

7. The method according to claim 1, characterized in that, The first metal layer includes at least one metal selected from the group consisting of steel, copper, aluminum, nickel, and silver.

8. The method according to claim 1, characterized in that, The initial chip board is provided, comprising: Provide a substrate and multiple sets of components of the radio frequency module; The components of each RF module are respectively soldered to the corresponding areas of the substrate and cleaned.

9. The method according to claim 8, characterized in that, The substrate has a welding area for connecting the components and a non-welding area outside the welding area, and the components of each RF module are welded to the corresponding area of ​​the substrate respectively, including: Coating a solder resist on the substrate to form a solder resist layer in the non-soldering area; Metallizing the surface of the components of each RF module and adding solder to form bumps in a reflow furnace; The components of each radio frequency module are reflow-soldered to the welding area of ​​the substrate.

10. A radio frequency module, comprising a substrate coated with a solder mask layer and a plurality of components fixed on the substrate, characterized in that, The RF module also includes a dry film covering the substrate and the multiple components, a first metal layer covering the side of the dry film facing away from the substrate, a plastic layer covering the side of the first metal layer facing away from the substrate, and a second metal layer covering the outer surface of the plastic layer; a cavity is formed between the dry film, the components and the substrate, and the first metal layer is electrically connected to the second metal layer.

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