Circuit board assembly, processing method of circuit board assembly and terminal equipment

Abstract

The invention discloses a circuit board assembly, a processing method of the circuit board assembly and terminal equipment, and belongs to the technical field of circuit board processing. The circuit board assembly comprises a circuit board, an electronic device, an insulation structure and a shielding structure. Wherein the electronic device is electrically connected to the circuit board. The insulating structure extends from the surface of the electronic device to the bottom surface of a device body of the electronic device so as to at least cover the device body. The shielding structure extends from the surface of the insulating structure to the circuit board to cover the electronic device. The circuit board assembly occupies less space in the thickness direction of the circuit board, and the insulating structure can be more firmly adhered to the surface of an electronic device and is not easy to peel and layer.

Description

Circuit board assembly, processing method of circuit board assembly and terminal device TECHNICAL FIELD

[0001] The present application belongs to the technical field of circuit board processing, and particularly relates to a circuit board assembly, a processing method of the circuit board assembly, and a terminal device. BACKGROUND

[0002] To meet the convenience and comfort of daily use of users, terminal devices are currently developing towards thin and light direction. Circuit boards such as mainboards of terminal devices are important carriers for integration of electronic devices of terminal devices, and occupy a larger space in the whole machine. Therefore, how to realize miniaturization of circuit boards and their accessory components plays an important role in thin and light development of the whole machine.

[0003] As shown in FIG. 3, in the traditional shielding scheme shown in FIG. 3, a shielding cover 11 on a circuit board (PCB) is welded on the PCB 12 to cover electronic devices 13 on the PCB 12 to shield electromagnetic interference. However, the shielding cover 11 has a large size in the thickness direction (Z direction shown in the figure) of the PCB 12, which causes Z direction space waste, and is not conducive to further miniaturization and thinning of the terminal device.

[0004] SUMMARY

[0005] The present application provides a circuit board assembly, a terminal device and a processing method of the circuit board assembly, which can solve the technical problem of Z direction space waste existing in the current shielding cover.

[0006] In a first aspect, an embodiment of the present application provides a circuit board assembly. The circuit board assembly includes a circuit board, an electronic device, an insulating structure and a shielding structure. The electronic device is electrically connected to the circuit board. The insulating structure extends to the bottom surface of the device body of the electronic device (i.e. the surface of the device body facing the circuit board) on the surface of the electronic device, so as to at least cover the device body, such as covering the entire electronic device. The shielding structure extends to the circuit board on the surface of the insulating structure, so as to cover the electronic device.

[0007] It should be noted that in the traditional shielding scheme, the shielding cover is usually an integrated structural member welded on the circuit board, and its size is determined according to the requirement that it can cover the electronic device and have an insulating gap with the electronic device for insulation in the case of covering the electronic device. In order to achieve better insulation effect, the electronic device has a safe insulating gap, which makes the height (i.e. the size in the Z direction) of the shielding cover larger.

[0008] In the circuit board assembly, the electronic device is covered by the insulating structure arranged on the surface of the electronic device, and the electronic device is covered by the shielding structure arranged on the surface of the insulating structure, so that the insulating structure is located between the shielding structure and the electronic device and plays an insulating role. It can be seen that, unlike the shielding cover in the traditional shielding scheme, the insulating gap is no longer relied on in the circuit board assembly, but the insulating structure is relied on for insulation. Since the insulating effect of the insulating structure is higher than that of the insulating gap (essentially the air in the insulating gap), the insulating structure can be made thinner. In the case that the insulating structure is made thinner, since the insulating structure is attached to the surface of the electronic device and the shielding structure is also attached to the surface of the insulating structure, the shielding structure can be closer to the electronic device and cover it, which makes the height of the shielding structure lower than that of the shielding cover, thereby reducing the waste of space in the thickness direction of the circuit board, and further facilitating the miniaturization and thinning of the terminal device.

[0009] In addition, in the circuit board assembly, the insulating structure extends along the surface of the electronic device to the bottom surface of the device body of the electronic device, and is inevitably distributed on the bottom surface of the electronic device. The part attached to the bottom surface of the electronic device can form a stronger pulling force with the electronic device, and in addition to the large attachment area of the insulating structure covering the entire electronic device, the insulating structure can be more firmly bonded to the surface of the electronic device without being easily peeled off, thereby improving the reliability in the board-level application environment.

[0010] Specifically, the device body is electrically connected to the circuit board through the connecting end located at the bottom of the device body. The insulating structure also extends from the bottom surface of the device body to the surface of the connecting end to cover the connecting end.

[0011] In this embodiment, the insulating structure covers the connecting end, which can play a role in filling glue, dispersing the stress of the connecting end, and improving the electrical connection reliability. On the other hand, it can also achieve the purpose of insulating the connecting end from the outside, thereby reducing the risk of short circuit between the solder joints.

[0012] In some design manners of the present application, the insulating structure is an insulating film, which is attached to the top surface of the electronic device and extends to the side surface of the electronic device, and is attached to the side surface of the electronic device and extends to at least the bottom surface of the device body. The side of the bottom surface of the device body is the bottom surface of the device body.

[0013] In the design, the insulation structure is attached with the insulation film, compared with the traditional shielding scheme in which the shielding cover and the electronic device are isolated by the insulation gap, on the one hand, the electronic device can be isolated with the insulation film, thereby reducing the space waste of the circuit board assembly in the thickness direction, and thus facilitating the miniaturization and thinning of the terminal device; on the other hand, the insulation film is thinner, occupies less thickness space and has weight benefits, and is also conducive to the miniaturization and thinning of the whole machine.

[0014] In some embodiments, the electronic device is a chip, and the device body of the chip is electrically connected to the circuit board through a plurality of chip soldering ends.

[0015] In at least one of the following conditions, the insulation film at least extends to the bottom surface of the device body of the chip:

[0016] The bottom gap H1 of the chip satisfies 10um≤H1≤150um;

[0017] The chip soldering end retraction size W1 satisfies W1≥100um;

[0018] The height D1 of the chip soldering end satisfies 150um≤D1≤300um;

[0019] The center distance D2 between the two adjacent chip soldering ends satisfies 300um≤D2≤600um.

[0020] It should be noted that the chip with any one of the above four conditions is considered as an electronic device with a small device bottom gap. In the related art, the insulation film formed by the hot pressing process has poor filling performance in the small device bottom gap of such a chip, and even cannot extend to the small device bottom gap, so that the device body cannot be covered, and the connection end cannot be covered. Therefore, the present embodiment provides an insulation film capable of bottom filling for such a chip, which extends to the bottom of the chip body, covers the device body, and even covers the connection end, and has good filling performance in the small device bottom gap.

[0021] In some embodiments of the present application, the electronic device is a passive element, and the device body of the passive element is electrically connected to the circuit board through a plurality of element soldering ends. In the case that the bottom gap H2 of the passive element is less than or equal to 30um, and / or the element soldering end retraction size W2 is greater than or equal to 30um, the insulation film at least extends to the bottom surface of the device body of the passive element. Therefore, the present embodiment provides an insulation film capable of bottom filling for such a passive element.

[0022] It should be noted that the passive element with either of the above two conditions is considered as an electronic device with a device bottom small gap. In the related art, the insulation film formed by the hot pressing process has poor filling property in the device bottom small gap of such passive element, and even cannot extend to the device bottom small gap, so as to fail to coat the device body and the connecting end. Therefore, the embodiment provides an insulation film capable of bottom filling such passive element, which extends to the bottom of the element body and coats the device body and even the connecting end, and has good filling property in the device bottom small gap.

[0023] In some embodiments of the present application, the number of electronic devices is multiple, and there is a gap between the multiple electronic devices; the insulation structure extends into the gap and extends to the bottom of the device body of each electronic device along the side of the corresponding gap of each electronic device, so as to at least coat the device body of each electronic device, respectively.

[0024] It should be noted that in the related art, the insulation film formed by the hot pressing process has poor filling property in the gap between the electronic devices, especially in the case of small gap, which makes the insulation film prone to peeling, delamination, film material rupture and other reliability problems. In this embodiment, the insulation film extends into the gap between each electronic device and extends to the bottom surface of the device body of each electronic device along the side of the corresponding gap of each electronic device, which will inevitably adhere to the side of the corresponding gap of each electronic device and the bottom surface of each electronic device. By adhering to the side of the corresponding gap of each electronic device and the bottom surface, a stronger pulling force can be formed between each electronic device, so that the insulation film can be more firmly attached to the surface of the electronic device without peeling, delamination, film material rupture, etc., thereby improving the reliability in the board-level application environment.

[0025] Optionally, the width of the gap is 1um-50um. In this case, it can be considered that the two electronic devices forming the gap have a small gap, i.e., a device-to-device small gap.

[0026] It should be noted that in the related art, the gap between devices is filled by the hot pressing process, which requires a higher gap between electronic devices, requiring the gap between electronic devices to be above 0.4mm, which is obviously not conducive to the high-density miniaturization design of the circuit board. Therefore, the embodiment protects an insulation film capable of better filling in a device-to-device small gap with a gap width of 1um-50um, so as to have the benefit of circuit board layout and be conducive to the high-density miniaturization design of the circuit board.

[0027] In some embodiments of the present application, the surface of the electronic device has a groove. In the case where the groove width H3 of the groove satisfies 100um≤H3≤700um, and / or the groove depth W3 of the groove is ≥20um, the insulation film is attached to the inner wall surface of the groove in a random shape.

[0028] It should be noted that the electronic device with the groove on the surface is referred to as a special recessed device in the embodiment. When the groove filling is performed on the special recessed device satisfying any one of the two conditions, the adhesion of the insulation film formed by the hot pressing process in the related art is not firm in the recessed area due to the factors such as the small pressure of the insulation film (the inner wall of the recessed position on the surface of the special recessed device is lower than the surrounding surface) and the peeling and delamination due to thermal expansion and cold contraction. Therefore, the embodiment provides the insulation film capable of conformal adhesion to the inner wall of the groove of the special recessed device.

[0029] In some embodiments of the present application, the thickness difference index T of the insulation film is ≤10%; wherein T=(Ta-Tb) / Ta, Ta and Tb are the thicknesses of the insulation film at any two positions.

[0030] It should be noted that the thickness difference index T is used to represent the thickness consistency of the insulation film. The higher the thickness difference index T, the higher the thickness consistency of the insulation film; the lower the thickness difference index T, the lower the thickness consistency of the insulation film. It can be understood that the higher the thickness consistency of the insulation film, the more uniform the thickness of the insulation film.

[0031] At present, there is no insulation film with a thickness difference index T lower than 10%. For example, the thickness of the insulation film formed by the hot pressing process is usually 50um-150um, and the thickness difference at different positions is more than 30um, that is, the thickness difference index T of the insulation film formed by the hot pressing process is at least 20%. Therefore, the embodiment protects an insulation film with a thickness difference index T lower than 10%, so that the thickness uniformity of the insulation film at each position of the electronic device is better, and the thickness is more uniform, which is beneficial to the electrical consistency design.

[0032] In some embodiments of the present application, the thickness of the insulation film at any position is 0.5um-40um.

[0033] It should be noted that there is no insulation film with a thickness of 0.5um-40um at present, for example, the thickness of the insulation film formed by the hot pressing process is usually 50um-150um. Therefore, the embodiment protects an insulation film with a thickness of 0.5um-40um, so that the thickness of the insulation film is thinner, which is beneficial to the light and thin of the circuit board assembly.

[0034] Exemplarily, the insulation film is realized by a plating process. The plating process can form the insulation film in the foregoing embodiments.

[0035] Compared with the insulation film formed by the hot pressing process, the film forming process converts the thin film material into gaseous atoms, molecules or ions, and deposits them on the surface of the electronic device, so the gap around the electronic device is low and has strong penetration, and the film material does not need to consider the tensile property, flowability and strength of the film material, and the insulation film can be formed into a shape covering the small gap at the bottom of the device and the small gap between the devices, thereby reducing the risk of reliability problems such as peeling, delamination and film material rupture of the insulation film.

[0036] In addition, compared with the insulation film formed by the hot pressing process, the film forming process forms the insulation film by depositing the thin film material, and the film layer thickness is not strongly related to the height and layout density of the electronic device, and does not involve the stretching of the film material by the hot pressing process, so the thickness difference index T of the insulation film can be less than 10%, and the thickness is more uniform.

[0037] In addition, compared with the insulation film formed by the hot pressing process, the film forming process does not involve the use of pressure to hot press the film material, but forms the insulation film by deposition, so it is not easy to have the problem of peeling and delamination of the insulation film due to the small pressure and the poor adhesion of the insulation film to the inner wall of the groove of the special concave device.

[0038] In addition, compared with the insulation film formed by the hot pressing process, the insulation film formed by the film forming process is more uniform in thickness and is not strongly related to the height and layout density of the electronic device, so there is no need to intentionally thicken the insulation film in order to prevent the film layer from being easily broken at the thinnest position. The thickness of the insulation film formed by the film forming process can be thinner, and the film layer thickness of nanometer to micrometer can be achieved. Based on this, the thickness of the insulation film formed by the film forming process can be 0.5um-40um, achieving ultra-thin, thereby facilitating the overall thinning of the circuit board assembly.

[0039] In addition, compared with the insulation film formed by the hot pressing process, the film forming process does not involve the stretching of the film material by the hot pressing process, so it is not easy to have the problem of film material thinning and film layer rupture due to large stretching rate, thereby preventing short circuit between the shielding film and the electronic device.

[0040] In addition, compared with the insulation film formed by the hot pressing process, the film forming process does not involve the stretching of the film material by the hot pressing process, so it is not easy to have the problem of film material thinning and film layer rupture due to large stretching rate, thereby preventing short circuit between the shielding film and the electronic device.

[0041] In some embodiments of the present application, the shielding structure is a shielding film, which is attached to the surface of the insulating film and extends to the circuit board. Compared with the shielding cover of the integrated structure, on the one hand, the electronic device can be shielded and protected, thereby reducing the space waste of the circuit board assembly in the thickness direction, and thus facilitating the miniaturization and lightness of the terminal device; on the other hand, the shielding thickness is thinner (the shielding cover needs to be thickened to maintain the flat shape due to the inability to attach), the occupied thickness space is smaller and has weight benefits, which is also conducive to the lightness and miniaturization of the whole machine.

[0042] Optionally, the thickness of the shielding film at any position is 2-40 um. This embodiment protects a shielding film with a thickness of 2-40 um, so that the thickness of the shielding film is thinner, which is conducive to the lightness of the circuit board assembly.

[0043] In another design of the present application, the insulating structure is an insulating glue. The shielding structure includes a conductive frame and a shielding film. The conductive frame encloses one side of the electronic device side surface. The insulating glue is filled in the conductive frame, distributed on the top surface of the electronic device and extends to the side surface of the electronic device, and distributed on the side surface of the electronic device and extends to the bottom surface of the electronic device; the insulating glue at least extends to the bottom surface of the device body, and the side of the bottom surface of the device body is the bottom surface of the device body. The inner wall surface of the conductive frame is attached to the side surface of the insulating glue and extends to the circuit board along the side surface of the insulating glue. The shielding film is attached to the top surface of the insulating glue and extends to the top end of the conductive frame away from the circuit board and is electrically connected with the conductive frame; wherein the side surface of the insulating glue is the area of the surface of the insulating glue corresponding to the side surface of the electronic device, and the top surface of the insulating glue is the area of the surface of the insulating glue corresponding to the top surface of the electronic device.

[0044] In this design, the insulating glue is distributed on the top surface, side surface and bottom surface of the electronic device, and the conductive frame and the shielding film are respectively on the side surface of the insulating glue and the top surface of the insulating glue, so that the insulating glue is isolated between the conductive structure formed by the shielding film and the conductive frame and the electronic device, and plays an insulating role. It can be seen that the circuit board assembly no longer relies on the insulating gap for insulation, but relies on the insulating glue for insulation. It can be understood that the insulating effect of the insulating glue is higher than that of the insulating gap, which makes the insulating glue thinner (compared to the size of the insulating gap) and attached to the surface of the electronic device. In the case that the insulating glue can be made thinner and the shielding film and the conductive frame are also attached to the surface of the insulating glue, the shielding structure formed by the shielding film and the conductive frame can be closer to the electronic device and cover it, which makes the height of the shielding structure lower than that of the shielding cover, thereby reducing the space waste in the thickness direction, and thus facilitating the further miniaturization and lightness of the terminal device.

[0045] Optionally, the ratio of the wall height and the wall width of the conductive frame is 2.4-6. The specific value of the ratio is determined according to the height of the electronic device enclosed by the conductive frame and the width of the ground pad on the circuit board to which the conductive frame is connected. The ratio should not be too large, otherwise it is easy to collapse during processing and cannot be formed.

[0046] Illustratively, the insulating glue is formed by a spraying process. The material used in the spraying process has high fluidity (compared to the hot-pressing process), which can achieve complete filling and no voids around the device, thereby fully covering the electronic device. On the one hand, it can increase the strength of the circuit board assembly; on the other hand, it can make the insulating glue less likely to peel off and delaminate, thereby improving the reliability of the circuit board assembly in the board-level application environment.

[0047] Illustratively, the shielding film in the above embodiments can be formed by any one of the spraying process, the printing process, the plating process, and the hot-pressing process.

[0048] Compared with the shielding film formed by the hot-pressing process, the shielding film formed by the plating process is more likely to extend to the small gap at the bottom of the device and the small gap between devices, has lower requirements for the gap at the bottom of the device and the gap between devices, is thinner and is less likely to have film material thinning and film layer rupture. The specific reasons can be adaptively referred to the above-mentioned related description of forming the insulating film by the plating process.

[0049] It can be understood that when the shielding film extends to the small gap at the bottom of the device, it can bind the insulating film from more areas, reducing the risk of delamination of the inner insulating film from the surface of the electronic device. When the shielding film extends to the small gap between devices, it can isolate the two adjacent electronic devices that need to be isolated, thereby reducing the electromagnetic interference between the two electronic devices. When the shielding film has lower requirements for the gap at the bottom of the device, it is also beneficial to the thinness and miniaturization of the whole machine. When the shielding film has lower requirements for the gap between devices, it is beneficial to the high-density and miniaturization design of the circuit board. When the shielding film is thinner, it occupies less thickness space and has weight benefits, which is also beneficial to the thinness and miniaturization of the whole machine. When the shielding film is less likely to have film material thinning and film layer rupture, the risk of shielding failure is lower.

[0050] Compared with the shielding film formed by the plating process, the shielding film formed by the spraying process or the printing process relies on the fluidity of the material and has weaker permeability to the gap, so it is not easy to extend to the area between the solder joints, which can reduce the risk of short circuit between the solder joints through the shielding film.

[0051] Compared with the shielding film formed by the hot-pressing process, the shielding film formed by the spraying process or the printing process also has the above-mentioned advantages of the shielding film formed by the plating process, which will be described below.

[0052] Compared with the shielding film formed by the hot pressing process, the shielding film formed by the spraying process or the printing process in the way of spraying the film material with high fluidity does not involve the stretching of the film material by the hot pressing process, and does not need to consider the stretchability, fluidity and strength of the film material, so the thickness is more uniform, and there is no need to deliberately thicken the film layer thickness to prevent it from being easily broken at the thinnest position. The thickness of the shielding film formed by the spraying process or the printing process can be thinner, and the thickness of the shielding film at any position can be 2um-40um, achieving ultra-thinness, thereby facilitating the overall thinning of the circuit board assembly. Of course, the hot pressing process can also form a shielding film with a thickness in this range, but the tool used for the hot pressing process requires extremely high requirements, resulting in extremely high cost.

[0053] Compared with the shielding film formed by the hot pressing process, the spraying process and the printing process do not involve the pressing of the film material, and do not need to consider the stretchability and strength of the film material, and rely on the fluidity of the film material to form a shielding film that can easily penetrate into the small gap between the device bottom and the small gap between the devices, which naturally reduces the risk of delamination of the inner insulating film from the surface of the electronic device, and reduces the electromagnetic interference between the two electronic devices. On the contrary, the spraying process and the printing process have lower requirements for the device bottom gap and the device gap, thereby facilitating the thinness, miniaturization and high-density miniaturization design of the entire machine.

[0054] Compared with the shielding film formed by the hot pressing process, the spraying process and the printing process do not involve the stretching of the film material by the hot pressing process, and are naturally less likely to cause the film material to thin and the film layer to break due to high stretching rate, thereby reducing the risk of shielding failure.

[0055] Of course, in the case of thinning the thickness of the insulating film (such as forming the insulating film by plating), the shielding film can also be formed by the hot pressing process. Due to the thinning of the insulating thickness, the overall circuit board assembly is also thinned.

[0056] It should be noted that compared with the previous design method, the thickness of the insulating glue formed by the spraying process is thicker, and occupies more thickness space. Therefore, in order to compensate for the occupation of the thickness space by the insulating glue, the embodiment preferentially forms the shielding film by the spraying process, the printing process and the plating process. Compared with the hot pressing process, the shielding film formed by the spraying process, the printing process and the plating process is thinner, thereby reducing the occupation of the thickness space, and further facilitating the miniaturization and thinness of the terminal device.

[0057] In some examples of the present application, the circuit board assembly includes a first electronic device and a second electronic device; the first electronic device and the second electronic device are two adjacent electronic devices on the circuit board; a row of ground terminals is distributed between the first electronic device and the second electronic device. The shielding structure is electrically connected with the row of ground terminals, forming a first shielding cavity covering the first electronic device and a second shielding cavity covering the second electronic device.

[0058] In this example, the shielding structure is attached and formed without being fixed on the circuit board in the manner of the solder pad. In this case, the problem of how to isolate the two electronic devices needs to be considered. The shielding structure is separated into two shielding cavities by being electrically connected with the row of ground terminals between the first electronic device and the second electronic device, for covering the first electronic device and the second electronic device, respectively. It can be seen that, compared with the traditional shielding scheme, the circuit board assembly only needs to arrange a row of ground terminals between the two adjacent electronic devices to be isolated, thereby having the layout area benefit and being conducive to the miniaturization of the whole machine.

[0059] In a second aspect, the embodiments of the present application provide a processing method of a circuit board assembly. The processing method of the circuit board assembly includes: electrically connecting an electronic device to a circuit board. An insulating structure is formed on a side of the circuit board where the electronic device is located, so that the insulating structure extends on the surface of the electronic device to the bottom surface of a device body of the electronic device to at least cover the device body. A shielding structure is formed on the side of the circuit board where the electronic device is located, so that the shielding structure extends on the surface of the insulating structure to the circuit board to cover the electronic device, thereby obtaining the circuit board assembly.

[0060] In some design manners of the present application, the formation of the insulating structure and the shielding structure on the side of the circuit board where the electronic device is located includes: forming an insulating film attached in a shape on the surface of the electronic device, so that the insulating film at least covers the device body as the insulating structure; and forming a shielding film attached in a shape on the surface of the insulating film, so that the shielding film extends on the surface of the insulating film to the circuit board as the shielding structure.

[0061] Optionally, the formation of the insulating film attached in a shape on the surface of the electronic device includes: forming the insulating film on the surface of the electronic device by a plating process.

[0062] In other design manners of the present application, the formation of the insulating structure and the shielding structure on the side of the circuit board where the electronic device is located includes: forming a conductive frame on the surface of the circuit board, so that the conductive frame surrounds the side to which the side surface of the electronic device faces; filling an insulating glue in the conductive frame to form an insulating glue body; the insulating glue body at least covers the device body as the insulating structure; forming a shielding film attached in a shape on the top surface of the insulating glue body, so that the shielding film extends from the top surface of the insulating glue body to the top end of the conductive frame away from the circuit board and is electrically connected with the conductive frame; and the shielding film and the conductive frame form the shielding structure.

[0063] Optionally, the conductive frame is filled with insulating glue, including: filling the conductive frame with insulating glue by a spraying process.

[0064] Optionally, the shielding film is formed to be attached to the circuit board, including: forming the shielding film to be attached to the circuit board by any one of a spraying process, a printing process, a plating process, and a hot-pressing process.

[0065] In a third aspect, an embodiment of the present application provides a terminal device. The terminal device includes a housing and a circuit board assembly provided by any one of the embodiments of the first aspect or obtained by the processing method provided by any one of the embodiments of the second aspect, and the circuit board assembly is located in the housing.

[0066] It can be understood that, in addition to the separate description, the processing method of the circuit board assembly provided by any one of the embodiments of the second aspect and the terminal device provided by the third aspect can adaptively refer to the beneficial effects described for the circuit board assembly provided by the first aspect, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0067] FIG. 1 is a perspective view of a terminal device provided by an embodiment of the present application;

[0068] FIG. 2 is an exploded view of the terminal device shown in FIG. 1;

[0069] FIG. 3 is a structural schematic view of a conventional shielding scheme using a shielding cover for electromagnetic shielding in the prior art;

[0070] FIG. 4 is a structural schematic view of a board-level film-coating shielding scheme provided by an embodiment of the present application;

[0071] FIG. 5 is a structural schematic view of a circuit board assembly provided by an embodiment of the present application;

[0072] FIG. 6 is a structural schematic view of another circuit board assembly provided by an embodiment of the present application;

[0073] FIG. 7 is a schematic view of the positional relationship between an insulating film and a ground pad in FIG. 5;

[0074] FIG. 8 is a schematic view of the positional relationship among a shielding film, an insulating film, and a ground pad in FIG. 5;

[0075] FIG. 9 is a schematic view of film material filling in the circuit board assembly formed by the board-level film-coating shielding scheme shown in FIG. 4;

[0076] FIG. 10 is a schematic view of the related structure involving the insulating film in the circuit board assembly shown in FIG. 5;

[0077] FIG. 11 is a schematic view of the gap required for insulating film filling in the circuit board assembly formed by the board-level film-coating shielding scheme shown in FIG. 4;

[0078] Fig. 12 is a schematic diagram of a structure related to the insulation film covering the chip in the circuit board assembly shown in Fig. 5;

[0079] Fig. 13 is a schematic diagram of a structure related to the insulation film covering the passive component in the circuit board assembly shown in Fig. 5;

[0080] Fig. 14 is a schematic diagram of the insulation film at the position of the device surface recess in the circuit board assembly formed by the board-level film covering shielding scheme shown in Fig. 4;

[0081] Fig. 15 is a schematic diagram of a structure related to the insulation film covering the special recessed device in the circuit board assembly shown in Fig. 5;

[0082] Fig. 16 is a schematic diagram of the thickness uniformity problem and the short circuit risk in the circuit board assembly formed by the board-level film covering shielding scheme shown in Fig. 4;

[0083] Fig. 17 is a schematic diagram of a structure related to the insulation thickness in the circuit board assembly shown in Fig. 5;

[0084] Fig. 18 is a schematic diagram of the film material rupture problem in the circuit board assembly obtained by the board-level film covering shielding scheme shown in Fig. 4;

[0085] Fig. 19 is a schematic diagram of another circuit board assembly provided by the embodiment of the present application;

[0086] Fig. 20 is a schematic diagram of the gap required for the shielding film to fill in the circuit board assembly formed by the board-level film covering shielding scheme shown in Fig. 4;

[0087] Fig. 21 is a schematic diagram of another circuit board assembly provided by the embodiment of the present application;

[0088] Fig. 22 is a schematic diagram of the contrast between the non-closed ring with a notch and the closed ring without a notch provided by the embodiment of the present application;

[0089] Fig. 23 is a top view of the circuit board assembly shown in Fig. 21;

[0090] Fig. 24 is a flowchart of a processing method of a circuit board assembly provided by the embodiment of the present application;

[0091] Fig. 25 is a flowchart of a processing method of the circuit board assembly shown in Fig. 5 provided by the embodiment of the present application;

[0092] Fig. 26 is a structure process flowchart corresponding to the processing method shown in Fig. 25;

[0093] Fig. 27 is a structure process diagram of the shielding film of the circuit board assembly shown in Fig. 19 provided by the embodiment of the present application;

[0094] Fig. 28 is a flowchart of a processing method of the circuit board assembly shown in Fig. 21 provided by the embodiment of the present application;

[0095] FIG. 29 is a structural process flow chart corresponding to the processing method shown in FIG. 28. DETAILED DESCRIPTION

[0096] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the drawings in the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0097] The terms "first" and "second" and the like in the specification and claims of the present application are used to distinguish different objects, rather than to describe a specific order of the objects. In the description of the embodiments of the present application, unless otherwise specified, "a plurality of" means two or more, for example, a plurality of processing units means two or more processing units, and the like.

[0098] The technical term "electrically connected" involved in the embodiments of the present application means connecting two electrical elements to realize the transmission of current between the electrical elements.

[0099] In the embodiments of the present application, the words "exemplarily" or "for example" and the like are used to represent as an example, illustration or description. Any embodiment or design scheme described as "exemplarily" or "for example" in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the words "exemplarily" or "for example" and the like are intended to present the relevant concept in a specific manner.

[0100] In the embodiments of the present application, x~y is used to represent [x, y], which means that the number x, the number y or any number between the two endpoint numbers can be taken.

[0101] Before introducing the embodiments of the present application, first introduce the related terms involved in the embodiments of the present application:

[0102] 1, "cladding", means that the cladding covers each surface of the cladding exposed outside to make it impossible to see the surface of the cladded part from the outside of the cladding.

[0103] The "at least cladding" mentioned in the embodiments of the present application means that in addition to cladding a certain structure, more structures can also be cladded.

[0104] 2, "covering", means that the covering covers part of the surface of the covered part exposed outside, similar to covering a quilt, so that it is impossible to see the surface of the covered part from the side facing the surface of the covering.

[0105] 3、"adhesion" refers to a state of adhesion of a thin object to the surface of a thick object, and the thick object supports the thin object.

[0106] 4、"conformal adhesion" refers to an adhesion member adhering to the surface of an adhered member, and the shape of the adhesion member changes as a whole following the change of the surface shape of the adhered member. This does not mean that the shapes of the adhesion member and the adhered member are consistent at each position, but only that they are generally consistent.

[0107] 5、coating process is a technology of converting a thin film material (also referred to as a target material or a coating material) into gaseous atoms, molecules or ions under the condition of vacuum or low-pressure gas discharge, and depositing them on the surface of a substrate to form a thin film on the surface of the substrate.

[0108] Exemplarily, the coating process can be various thin film deposition processes, and the thin film deposition process can be chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. The PVD can be evaporation, sputtering, ion plating, arc plating, plasma, etc.

[0109] 6、hot pressing process is a method of pressing two or more materials together under the condition of heating and applying pressure, which can be performed under vacuum conditions.

[0110] 7、spraying process is a coating method of dispersing a thin film material with fluidity into uniform and fine mist droplets by means of pressure or centrifugal force, and spraying the mist droplets on the surface of a coated object.

[0111] 8、printing process is a printing method of spraying ink through a nozzle on the surface of an object, which is similar to the spraying process in principle, but is usually used for printing a certain thin film layer.

[0112] Exemplarily, please refer to FIG. 1 and FIG. 2, FIG. 1 is a perspective view of a terminal device 10 provided by an embodiment of the present application, and FIG. 2 is a structural exploded view of the terminal device 10 shown in FIG. 1.

[0113] The terminal device 10 is a mobile phone, which includes a display screen 100, a housing 200 and a circuit board assembly 300. The components will be described below.

[0114] The display screen 100 is used to display display content such as images and videos.

[0115] The shell 200 is used to carry the display screen 100. The display screen 100 and the shell 200 jointly enclose a containing space of the terminal device 10, so as to place functional components of the terminal device 10, such as the circuit board assembly 300, the battery and the like, in the containing space, and meanwhile, the containing space forms a sealing and protection effect on the functional components located in the containing space.

[0116] As shown in FIG. 2, the shell 200 includes a back cover 210, a side frame 220 and a middle plate 230.

[0117] The back cover 210, also referred to as a battery cover, is located at a backlight side of the display screen 100 and is stacked with the display screen 100. It can be understood that a light-out side of the display screen 100 is a side facing a screen display area of the display screen 100, and an opposite side of the light-out side of the display screen 100 is the backlight side of the display screen 100. For the convenience of the following description, an XYZ coordinate system is established, and a width direction of the terminal device 10 is defined as a Y-axis direction, a length direction of the terminal device 10 is defined as an X-axis direction, and a thickness direction of the terminal device 10 is defined as a Z-axis direction (referred to as Z direction for short). It can be understood that a stacking direction of the display screen 100 and the back cover 210 in the terminal device 10 is the Z-axis direction. A plane in which the display screen 100 or the back cover 210 is located is a Z-XY plane. It should be noted that the coordinate system of the terminal device 10 can be flexibly set according to actual needs.

[0118] The side frame 220 is located at a side of the back cover 210 facing the display screen 100 and is fixed to the back cover 210. Exemplarily, the side frame 220 can be fixedly connected to the back cover 210 by an adhesive; the side frame 220 can also be an integrally formed structure with the back cover 210, that is, the side frame 220 and the back cover 210 are an integral structure.

[0119] The middle plate 230 is stacked between the back cover 210 and the display screen 100 and is fixed to an inner surface of the side frame 220. Exemplarily, the middle plate 230 can be fixed to the side frame 220 by welding; the middle plate 230 can also be an integrally formed structure with the side frame 220, which is commonly referred to as a middle frame. The middle plate 230 is used as a structural “skeleton” of the terminal device 10 and is used to mount functional components of the terminal device 10, such as the circuit board assembly 300, the battery 400 and the like.

[0120] As shown in FIG. 2, the circuit board assembly 300 and the battery 400 are mounted at a side of the middle plate 230 facing the back cover 210. Of course, in some other embodiments, the circuit board assembly 300 and the battery 400 can also be mounted at a side of the middle plate 230 facing away from the back cover 210, which is not limited in the embodiments of the present application.

[0121] The circuit board assembly 300 is a structure including a circuit board (PCB) and electronic devices integrated on the circuit board. It can be understood that the circuit board can be a main board of the terminal device 10 (Fig. 2 shows this case), or a sub-board of the terminal device 10.

[0122] It can be understood that Figs. 1 and 2 only schematically show some components included in the terminal device 10, and the actual shape, actual size, actual position and actual structure of these components are not limited by Figs. 1 and 2. In other embodiments of the present application, the terminal device 10 can include more or fewer components than shown, or combine certain components, or split certain components, or different component arrangements.

[0123] In order to shield electromagnetic interference and improve the reliability of the circuit board assembly 300, the circuit board assembly 300 usually needs to be provided with some shielding-related structures to electromagnetically shield the electronic devices of the circuit board assembly 300. For example, as shown in Fig. 3, which is a structural schematic diagram of a conventional shielding scheme using a shielding cover 11 for electromagnetic shielding in the prior art. Fig. 3 can be understood as a kind of cross-sectional view of the circuit board assembly 300 shown in Fig. 2 in the X-ZY plane.

[0124] In this conventional shielding scheme, the shielding cover 11 is usually soldered on the PCB 12 of the circuit board assembly 300 by means of tin paste, covering the electronic devices 13 on the PCB 12, blocking the electromagnetic interference of the electronic devices 13 on the PCB 12, and at the same time protecting the electronic devices 13 from mechanical impact. However, the shielding cover 11 in this conventional shielding scheme has a large size (i.e. high height) in the thickness direction (Z direction shown in the figure) of the PCB 12, causing a waste of space in the Z direction,

[0125] In view of the high height problem of the shielding cover 11 in the conventional shielding scheme, the embodiments of the present application provide a kind of board-level shielding integration scheme.

[0126] Unlike the shielding cover 11 in Fig. 3, in the board-level shielding integration scheme provided by the embodiments of the present application, the structure for realizing electromagnetic shielding is not an integrated structure formed independently, but a structure integrated on the PCB 12 and attached to the surface of the electronic device 13. By being attached closely to the surface of the electronic device 13, this board-level shielding integration scheme has benefits in height, which is conducive to further thinning and miniaturization of the terminal device. The board-level shielding integration scheme provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0127] First, the embodiments of the present application provide a kind of board-level film shielding scheme shown in Fig. 4, which belongs to a kind of board-level shielding integration scheme.

[0128] As shown in FIG. 4, FIG. 4 is a structural schematic diagram of a board-level film-coated shielding scheme provided by an embodiment of the present application. FIG. 4 can be understood as another cross-sectional view of the circuit board assembly 300 shown in FIG. 2 in the X-ZY plane.

[0129] In the board-level film-coated shielding scheme shown in FIG. 4, the insulating film 21 and the shielding film 22 are coated on the PCB 23 of the circuit board assembly 300 through a hot-pressing process to perform conformal shielding and protection on the electronic device 24 on the PCB 23.

[0130] Since the board-level film-coated shielding scheme can achieve conformal shielding and protection, and the insulating film 21 and the shielding film 22 are thin in thickness and closely adhere to the electronic device 24 in sequence, compared with the case where the insulating gap 14 needs to be set in the traditional shielding scheme shown in FIG. 3 to ensure the insulating effect, the board-level film-coated shielding scheme can obtain Z-direction (i.e., the thickness direction of the PCB 23) space benefits, which is conducive to thinning the whole machine.

[0131] In addition, compared with the case where the shielding cover 11 in the traditional shielding scheme shown in FIG. 3 uses a metal with high density (such as white brass, aluminum alloy, or stainless steel, etc.), the insulating film 21 and the shielding film 22 are light and thin film layers, which have weight benefits, and are conducive to reducing the weight of the whole machine.

[0132] In addition, compared with the case where the pad width M1 of the ground pad 121 plus the avoidance width M2 (the width of the gap set to avoid the electronic device 13) occupies the layout area of the PCB 12 in the traditional shielding scheme shown in FIG. 3, due to the setting of the insulating film 21, the ground pad 25 does not need to avoid the electronic device 24 through the above-mentioned wider avoidance width M2, but is isolated through the thinner insulating film 21. Compared with the traditional shielding scheme, the board-level film-coated shielding scheme has layout area benefits, which is conducive to miniaturization of the whole machine.

[0133] In addition, compared with the case where two shielding covers 11 need two rows of ground pads 121 to be welded in the traditional shielding scheme shown in FIG. 3, the shielding film 22 used to isolate two electronic devices 24 from each other in this board-level film-coated shielding scheme can be welded to the same row of ground pads 25, thereby forming two shielding cavities to isolate and shield the adjacent two electronic devices 24. Therefore, only one row of ground pads 25 needs to be set, and therefore, the board-level film-coated shielding scheme has layout area benefits.

[0134] It can be seen that the board-level film-coated shielding scheme can solve the problems of large layout area, large weight and high height of the traditional shielding scheme using the shielding cover 11 in FIG. 3 due to the realization of shielding integration. However, the board-level film-coated shielding scheme shown in FIG. 4 can introduce a series of new problems, such as the problem of film layer peeling and delamination caused by the inability of the board-level film-coated shielding scheme to fill the bottom of the electronic device 24. Subsequently, the problems of the board-level film-coated shielding scheme shown in FIG. 4 will be described one by one, which will not be described in detail here. In view of this, the embodiment of the present application also provides another new board-level shielding integration scheme. The new board-level shielding integration scheme also belongs to the above-mentioned board-level shielding integration scheme and can be applied to the circuit board assembly of a terminal device.

[0135] It should be noted that the terminal device to which the new board-level shielding integration scheme provided by the embodiment of the present application is applied can be a mobile phone, a tablet computer, a notebook computer or other electronic equipment with electromagnetic interference shielding requirements, and the specific form of the terminal device is not specially limited in the embodiment of the present application. The terminal device 10 shown in FIGS. 1 and 2 is taken as an example for description.

[0136] The new board-level shielding integration scheme can form an insulating structure and a shielding structure on the circuit board of the circuit board assembly, which are used for electromagnetic interference shielding of the electronic device on the circuit board. Specifically, in the circuit board assembly, the insulating structure extends from the surface of the electronic device to the bottom surface of the device body of the electronic device to at least cover the device body of the electronic device; and the shielding structure extends from the surface of the insulating structure to the circuit board to cover the electronic device.

[0137] It can be understood that the extension of the insulating structure from the surface of the electronic device to the bottom surface of the device body of the electronic device can realize the bottom filling of the electronic device. In the case of filling the insulating structure to the bottom surface of the device body, the part of the insulating structure extending to the bottom surface of the device body can form a stronger pulling force with the electronic device, and in addition, the large attachment area of the insulating structure through the covering of the device body, which makes the insulating structure more firmly attached to the surface of the electronic device without easy delamination and peeling, thereby improving the reliability in the board-level application environment.

[0138] The new board-level shielding integration scheme provided by the embodiment of the present application will be described below in combination with FIGS. 5 to 23.

[0139] Exemplarily, as shown in FIG. 5, FIG. 5 is a structural schematic diagram of a circuit board assembly 300 provided by the embodiment of the present application. FIG. 5 can be understood as a kind of cross-sectional view of the circuit board assembly 300 shown in FIG. 2 in X-ZY plane. The circuit board assembly 300 shown in FIG. 5 adopts the above-mentioned new board-level shielding integration scheme.

[0140] Specifically, the circuit board assembly 300 includes a circuit board 310 and an electronic device 320.

[0141] The circuit board 310 (also referred to as PCB 310) is an important carrier of the electronic devices 320, and generally has metal traces and / or interfaces and the like thereon to facilitate electrical connection between two electronic devices 320 integrated on the PCB 310, and / or electrical connection between an electronic device 320 integrated on the PCB 310 and an electronic device not integrated on the PCB 310.

[0142] The electronic devices 320 can be active devices and passive elements. The number of electronic devices 320 is at least one, and FIG. 5 shows a case of two electronic devices 320. For the sake of distinction and illustration, the two electronic devices 320 are referred to as a first electronic device 320a and a second electronic device 320b in the embodiments of the present application. The first electronic device 320a is taken as an example of an integrated circuit (IC) for illustration, and the integrated circuit is also referred to as a chip, which is represented by IC in the figure. The second electronic device 320b is taken as an example of a passive element for illustration, and the passive element can be a resistor, an inductor, or a capacitor, which is represented by RLC in the figure. It can be understood that the number and type of electronic devices 320 shown in FIG. 5 do not constitute a limitation on the electronic devices 320 of the circuit board assembly.

[0143] The electronic devices 320 are electrically connected to the PCB 310 by welding or the like, and can be electrically connected to other electronic devices (such as electronic devices integrated on the PCB 310 or electronic devices not integrated on the PCB 310) through metal traces and / or interfaces and the like on the PCB 310.

[0144] Exemplarily, in combination with FIG. 5, the electronic device 320 includes a device body 321 and a connection end 322 located at the bottom of the device body 321. The bottom of the device body 321 refers to the side to which the bottom surface (i.e., the surface of the device body 321 facing the PCB 310) of the device body 321 faces, and it can be understood that the bottom of the device body 321 belongs to the bottom of the electronic device 320. In the embodiments of the present application, the bottom of the electronic device 320 is also referred to as the device bottom.

[0145] The device body 321 is a main structure for implementing the function of the electronic device 320, and the connecting end 322 is a terminal for electrically connecting the electronic device 320 to the PCB 310. The connecting end 322 is led out from the device body 321 and protrudes from the device body 321 to electrically connect to the PCB 310, so that the electronic device 320 is electrically connected to the PCB 310, such as a device pad 350 on the PCB 310. For example, for the IC shown in FIG. 5, the connecting end 322 can be a solder ball, such as a ball grid array package (BGA) and the like. The connecting end 322 and the device pad 350 are labeled at the IC in the figure, and it can be understood that the positions and structures of the connecting end 322 and the device pad 350 at the RLC can be adaptively referred to.

[0146] In this example, the connecting end 322 is part of the electronic device 320. Of course, in some other examples, the connecting end 322 can not be considered as part of the electronic device 320, that is, the electronic device 320 includes the device body 321 but does not include the connecting end 322. The embodiments of the present application are described in the first example.

[0147] For ease of understanding and description, the surface of the device body 321 facing the PCB 310 is referred to as the bottom surface of the device body 321, and the surface of the device body 321 facing away from the PCB 310 is referred to as the top surface of the device body 321 (that is, the surface opposite to the bottom surface of the device body 321), and the surface connected to the top surface and the bottom surface of the device body 321 is referred to as the side surface of the device body 321. It can be understood that whether the electronic device 320 includes the connecting end 322 or not, the top surface of the electronic device 320 is formed by the top surface of the device body 321, and the side surface of the electronic device 320 is formed by the side surface of the device body 321; in the case where the electronic device 320 includes the connecting end 322, the bottom surface of the electronic device 320 includes the non-connection area of the bottom surface of the device body 321 and the non-connection area of the surface of the connecting end 322; in the case where the electronic device 320 does not include the connecting end 322, the bottom surface of the electronic device 320 includes the non-connection area of the bottom surface of the device body 321. The non-connection area of the bottom surface of the device body 321 and the non-connection area of the surface of the connecting end 322 will be described later.

[0148] In order to realize electromagnetic interference shielding, in the circuit board assembly 300 shown in FIG. 5, the insulating structure in the above-mentioned new type of integrated shielding scheme for a board is implemented by an insulating film 330 formed by a film plating process, and the shielding structure is implemented by a shielding film 340 formed by a hot pressing process. The insulating film 330 and the shielding film 340 are labeled at the IC in the figure, and it can be understood that the positions and structures of the insulating film 330 and the shielding film 340 at the RLC can be adaptively referred to.

[0149] First, the insulating film 330 formed by the film plating process is described.

[0150] The insulating film 330 formed by the coating process is attached to the surface of the electronic device 320, extends from the surface of the electronic device 320 to the bottom surface of the device body 321 (i.e. the surface of the device body 321 facing the PCB 310), and covers at least the device body 321.

[0151] The extension of the insulating film 330 from the surface of the electronic device 320 to the bottom surface of the device body 321 means that the insulating film 330 is attached to the surface of the electronic device 320 and extends to the bottom surface of the device body 321.

[0152] For example, FIG. 5 shows a case where the insulating film 330 covers the entire electronic device 320 (including all the connecting terminals 322 and the device body 321). In this case, the insulating film 330 is the covering member, the electronic device 320 is the covered member, and the exposed surface of the electronic device 320 includes the exposed surface of the device body 321 and the exposed surface of the connecting terminals 322.

[0153] As shown in FIG. 5, the surface of the device body 321, except for the area of the bottom surface of the device body 321 used for electrical connection (hereinafter referred to as the connecting area of the bottom surface of the device body 321, and the remaining area is referred to as the non-connecting area of the bottom surface of the device body 321), is exposed; the surface of the connecting terminals 322, except for the area used for electrical connection between the device body 321 and the PCB 310 (hereinafter referred to as the first connecting area of the surface of the connecting terminals 322, and the area used for electrical connection between the PCB 310 and the connecting terminals 322 is referred to as the second connecting area of the surface of the connecting terminals 322, and the remaining area is referred to as the non-connecting area of the surface of the connecting terminals 322), is exposed.

[0154] Therefore, the exposed surface of the electronic device 320 includes the top surface of the device body 321 (i.e. the top surface of the electronic device 320), the side surface of the device body 321 (i.e. the side surface of the electronic device 320), the non-connecting area of the bottom surface of the device body 321, and the non-connecting area of the surface of the connecting terminals 322. Among them, the non-connecting area of the bottom surface of the device body 321 and the non-connecting area of the surface of the connecting terminals 322 form the exposed surface of the bottom surface of the electronic device 320.

[0155] It can be understood that the bottom surface of the electronic device 320 is formed by the non-connection area of the bottom surface of the device body 321, the non-connection area of the surface of the connection end 322, and the second connection area of the surface of the connection end 322. Since the bottom surface of the electronic device 320 is electrically connected to the PCB 310 through the second connection area of the surface of the connection end 322, the second connection area of the surface of the connection end 322 included in the bottom surface of the electronic device 320 is not exposed. Therefore, the surface of the bottom surface of the electronic device 320 exposed to the outside includes the non-connection area of the bottom surface of the device body 321 and the non-connection area of the surface of the connection end 322.

[0156] Based on this, in FIG. 5, the insulating film 330 covers the electronic device 320, which means that the top surface of the electronic device 320, the side surface of the electronic device 320, and the surface of the bottom surface of the electronic device 320 exposed to the outside are covered, so that the surface of the electronic device 320 cannot be seen from the outside of the insulating film 330.

[0157] Therefore, when the insulating film 330 extends on the surface of the electronic device 320, specifically, the insulating film 330 is attached to the top surface of the electronic device 320 and extends to the side surface of the electronic device 320 by bending, and the insulating film 330 is attached to the non-connection area of the bottom surface of the device body 321 and the non-connection area of the connection end 322 by bending on the side surface of the electronic device 320, so as to cover the top surface of the electronic device 320, the side surface of the electronic device 320, and the surface of the bottom surface of the electronic device 320 exposed to the outside, thereby achieving the covering of the electronic device 320.

[0158] It should be noted that in some other embodiments, the insulating film 330 can also only cover the device body 321 of the electronic device 320, without covering the connection end 322 of the device body 321. This is shown in the circuit board assembly 300 shown in FIG. 6. As shown in FIG. 6, the insulating film 330 is attached to the top surface of the electronic device 320 and extends to the side surface of the electronic device 320 by bending, and the insulating film 330 is attached to the non-connection area of the bottom surface of the device body 321 by bending on the side surface of the electronic device 320, so as to cover the top surface of the electronic device 320, the side surface of the electronic device 320, and the non-connection area of the bottom surface of the device body 321, thereby achieving the covering of the device body 321.

[0159] It can be understood that, compared with the embodiment in FIG. 6 in which the insulating film 330 does not cover the connection end 322, in FIG. 5, since the insulating film 330 covers the connection end 322, on the one hand, the insulating film 330 can play a role of underfilling glue, dispersing the stress of the connection end 322, thereby improving the electrical connection reliability; on the other hand, the insulating film 330 can also reduce the risk of short circuit between the solder joints. It should be noted that subsequent embodiments take the covering of the entire electronic device 320 by the insulating film 330 as an example for description.

[0160] According to the foregoing, the insulating film 330 shown in FIG. 5 is formed by a plating process. Since the plating process converts a thin film material into gaseous atoms, molecules or ions and deposits them on the surface of the electronic device 320, it has low requirements for the gap around the device and strong penetration, so that the insulating film 330 formed thereby can extend to the bottom of the device body of the electronic device 320 for conformal coating. When the insulating film 330 is formed by a plating process, the plating material of the insulating film 330 can be an organic material, an inorganic material or an organic / inorganic composite material having insulating properties.

[0161] Exemplarily, the organic material having insulating properties can be a resin, such as epoxy resin, polybenzoxazole (PBO), polyimide (PI), Parylene, PET (polyethylene terephthalate, organic), PTFE (polytetrafluoroethylene, organic), TPU (thermoplastic polyurethane), FEP (fluorinated ethylene propylene), PFA (perfluoroalkoxy), HDPE (high-density polyethylene, organic) and the like; and the inorganic material having insulating properties can be boron nitride, silicon nitride, aluminum nitride, aluminum oxide, silicon dioxide and the like.

[0162] It should be noted that the insulating film 330 formed by the plating process can extend from the surface of the electronic device 320 to the bottom surface of the device body 321 to coat the electronic device 320.

[0163] The reason will be analyzed later, which will not be described here. Of course, in other embodiments, if other processes can make the insulating film 330 extend from the surface of the electronic device 320 to the bottom surface of the device body 321 to coat the electronic device 320, it is also within the protection scope of the embodiments of the present application.

[0164] In some embodiments of the present application, please continue to refer to Figure 5, the insulating film 330 extends to the PCB 310 from the bottom surface of the device body 321 and adheres to the surface of the PCB 310 to cover the surface of the PCB 310 on the side where the electronic device 320 is located (i.e. the upper surface of the PCB 310 shown in the figure), thereby improving the waterproof performance of the PCB. Of course, in other embodiments, the insulating film 330 can also not cover the upper surface of the PCB 310, and the embodiments of the present application do not limit this. In addition, in Figure 5, the insulating film 330 is integrally formed, and in other embodiments, the insulating film 330 can also be individually coated on each electronic device 320, and the embodiments of the present application do not limit this.

[0165] Secondly, the shielding film 340 formed by the hot pressing process is described.

[0166] The shielding film 340 adheres to the surface of the insulating film 330 and extends to the circuit board 310 from the surface of the insulating film 330 to cover the electronic device 320. The shielding film 340 extending to the circuit board 310 from the surface of the insulating film 330 means that the shielding film 340 is attached to the surface of the insulating film 330 and extends to the circuit board 310.

[0167] In Figure 5, the shielding film 340 is a covering member, and the electronic device 320 is a covered member. The surface of the electronic device 320 exposed to the outside is described above. It should be noted that in the embodiments of the present application, the surface of the electronic device 320 exposed to the outside is determined when the insulating film 330 is not attached. Based on this, the shielding film 340 can cover the electronic device 320 by covering all or part of the top surface of the electronic device 320, the side surface of the electronic device 320, the non-connection area of the bottom surface of the device body 321 and the non-connection area of the surface of the connection end 322, thereby covering the electronic device 320.

[0168] It should be noted that for the embodiments of the present application, the shielding film 340 covers the electronic device 320 on the PCB 310, and as the name implies, the bottom surface of the electronic device 320 can not be covered, that is, the shielding film 340 at least covers the top surface of the electronic device 320 and the side surface of the electronic device 320, thereby covering the electronic device 320 on the PCB 310.

[0169] In the embodiment shown in FIG. 5, the shielding film 340 covers the top surface of the electronic device 320 and the side surface of the electronic device 320, but does not cover the bottom surface of the electronic device 320. Specifically, the shielding film 340 is attached to the surface of the insulating film 330 corresponding to the top surface of the electronic device 320, and extends to the surface of the insulating film 330 corresponding to the side surface of the electronic device 320, and extends to the PCB 310, and extends to the surface of the PCB 310 away from the side surface of the electronic device 320, so as to cover the top surface of the electronic device 320 and the side surface of the electronic device 320, and cover the electronic device 320 on the PCB 310. Of course, in other embodiments, the shielding film 340 can cover at least part of the bottom surface of the electronic device 320 when covering the top surface of the electronic device 320 and the side surface of the electronic device 320, so as to cover the electronic device 320 on the PCB 310.

[0170] According to the foregoing, the shielding film 340 shown in FIG. 5 is formed by a hot pressing process. The hot pressing process can make the shielding film 340 extend to the PCB 310 along the surface of the insulating film 330. It should be noted that the thickness of the shielding film 340 at any position formed by the hot pressing process can be 15um-100um. The thinner the shielding film 340, the higher the requirement for the tool used in the hot pressing process, and the higher the cost.

[0171] When the shielding film 340 is formed by the hot pressing process, the hot pressing material of the shielding film 340 can be a material with conductive properties. For example, the material with conductive properties can be a mixture of resin and metal particles (or other conductive materials). The resin can be epoxy resin, PBO, PI, Parylene, PET, PTFE, TPU, FEP, PFA, HDPE, etc. The metal particles can be any one of elemental metals such as copper, nickel, chromium, aluminum, silver, gold, etc. or metal alloys. The other conductive materials can be graphene or other two-dimensional sheet-shaped conductive materials.

[0172] It should be noted that due to the stretching effect of the material during pressing, the shielding film 340 formed by the hot pressing process can be attached to the surface of the electronic device 320 and extend to the PCB 310 along the surface of the insulating film 330, so as to cover the electronic device 320 on the PCB 310. Of course, in other embodiments, if other processes can make the shielding film 340 extend to the PCB 310 along the surface of the insulating film 330 to cover the electronic device 320 on the PCB 310, it is also within the protection scope of the embodiments of the present application.

[0173] Optionally, to improve the reliability of the shielding film 340, the circuit board assembly 300 shown in FIG. 5 can further include a protective film 360 attached to the surface of the shielding film 340 to protect the shielding film 340. The protective film 360 can have the following functions for the shielding film 340, but is not limited to: anti-abrasion, anti-metal oxidation, waterproof, electrical isolation, and the like. Of course, in other embodiments, the protective film 360 can also not be provided.

[0174] In the implementation process, the protective film 360 can be realized by a hot pressing process, a spraying process, a printing process, or a plating process. Since the plating process can rely on the deposition and growth of atomic-level plating materials, and the spraying process or the printing process relies on the fluidity of the material, compared with the plating process, the latter has weaker penetration of the gap, and the thickness and thickness uniformity of the formed film layer are slightly worse.

[0175] The material of the protective film 360 can be a material with insulating properties, which can be set with reference to the material of the insulating film 330 described above. The thickness of the protective film 360 formed by the plating process can be 5um-15um. Exemplarily, the thickness of the protective film 360 is 5um, 6um, 8um, 13um, or 15um.

[0176] In the circuit board assembly shown in FIG. 5, the electronic device 320 is covered by setting the insulating film 330 on the surface of the electronic device 320, and the electronic device 320 is covered on the PCB 310 by setting the shielding film 340 on the surface of the insulating film 330, so that the insulating film 330 is located between the shielding film 340 and the electronic device 320, and the shielding film 340 and the electronic device 320 are isolated to play an insulating role. It can be seen that, unlike the shielding cover 11 shown in FIG. 3, the circuit board assembly no longer relies on the insulating gap 14 shown in FIG. 3 for insulation, but relies on the insulating film 330 for insulation. Since the insulating effect of the insulating film 330 is higher than that of the insulating gap 14 (essentially the air in the insulating gap 14) in FIG. 3, the insulating film 330 can be made thinner (compared to the size of the gap in FIG. 3). In the case where the insulating film 330 is made thinner, because the insulating film 330 is attached to the surface of the electronic device 320 and the shielding film 340 is also attached to the surface of the insulating film 330, the shielding structure formed by the shielding film 340 can be closer to the electronic device 320 and cover it, which makes the height of the shielding structure formed by the shielding film 340 lower than that of the shielding cover, thereby reducing the waste of space in the Z direction, and further facilitating the miniaturization and thinning of the terminal device.

[0177] In addition, compared with the integrated shielding cover 11 shown in FIG. 3, on one hand, the electronic device 320 can be shielded and protected in a form-fitting manner, so as to reduce the waste of space in the Z direction of the circuit board assembly, thereby facilitating the miniaturization and lightness of the terminal device; on the other hand, the shielding film 340 is thinner (the shielding cover 11 needs to be thickened to maintain the flat shape due to the inability to be attached), occupies less space in the Z direction and has weight benefits, which is conducive to the lightness and miniaturization of the whole machine.

[0178] In some embodiments of the present application, please continue to refer to FIG. 5, the PCB 310 is provided with a grounding end 370, such as the grounding pad 370 shown in FIG. 5, and subsequent embodiments take the grounding pad 370 as an example for description. The grounding pad 370 is distributed on the side of the electronic device 320.

[0179] Please refer to FIGS. 5 and 7, FIG. 7 is a schematic diagram of the position relationship between the insulating film 330 and the grounding pad 370 in FIG. 5. The insulating film 330 also extends to the grounding pad 370 along the surface of the PCB 310 away from the electronic device 320 at the bottom of the device body 321. The surface of the grounding pad 370 is reserved with a grounding area. The width A of the grounding area is 0.1mm-0.5mm, and the grounding resistance of the grounding pad 370 is 10mΩ-100mΩ. Exemplarily, the width A of the grounding area can be 0.1um, 0.2um, 0.3um, 0.4um, 0.5um; and the grounding resistance can be 10mΩ, 20mΩ, 34mΩ, 55mΩ, 75mΩ, 84mΩ, 100mΩ.

[0180] Thus, please refer to FIG. 8, which is a schematic diagram of the position relationship among the shielding film 340, the insulating film 330 and the grounding pad 370 in FIG. 5. The shielding film 340 also extends to the grounding pad 370 along the surface of the insulating film 330 and is electrically connected with the grounding pad 370, so as to release the accumulated current on the shielding film 340 through the grounding pad 370, thereby playing an electromagnetic shielding role. Specifically, the shielding film 340 extends to the grounding area of the grounding pad 370, and is bonded with the grounding area of the grounding pad 370 to form an electrical connection between the shielding film 340 and the grounding pad 370.

[0181] It should be noted that in Figure 3, the shielding cover 11 is electrically connected to the ground pad 121 by a surface mounted technology (SMT) welding process. In the SMT process, the shielding cover 11 has a certain tolerance in placement, and in addition, there are other tolerances such as shape. Therefore, the width of the ground pad 121 cannot be too small. In this embodiment, the shielding film 340 is electrically connected by being attached to the ground pad 370. There is no placement tolerance of the shielding cover 11 and no shape tolerance as in Figure 1. Therefore, the width A of the required grounding area is smaller, which allows the width (such as the pad width) of the ground pad 370 to be smaller, resulting in a layout area gain for the circuit board assembly, which is beneficial to the miniaturization of the entire machine.

[0182] Since the insulating film 330 extends to the ground pad 370, and the shielding film 340 extends along the surface of the insulating film 330 to the ground pad 370, it is clear that the area between the ground pad 370 and the electronic device 320 is isolated by the thin insulating film 330 and the electronic device 320. Therefore, the ground pad 370 does not need to have a wider avoidance width M2 as shown in Figure 3 to avoid the electronic device 320. Compared with the conventional scheme shown in Figure 3, the circuit board assembly has a layout area gain, which is beneficial to the miniaturization of the entire machine.

[0183] Optionally, please continue to refer to Figure 5. In order to obtain more layout area gain and further promote the miniaturization of the entire machine, Figure 5 shows a case where a row of ground pads 370 is distributed between two adjacent electronic devices 320 (i.e., a first electronic device 320a and a second electronic device 320b) that need to be isolated. The "row of ground pads 370" refers to a plurality of ground pads 370 arranged in a row.

[0184] The shielding film 340 can be electrically connected to the row of ground pads 370 to form a first shielding cavity covering the first electronic device 320a and a second shielding cavity covering the second electronic device 320b.

[0185] It can be understood that the shielding cover 11 in Figure 3 is a one-piece structure that is fixed to the PCB 310 by the pads to form a shielding cavity. When two shielding covers 11 are used to isolate two adjacent electronic devices 13, two rows of ground pads 121 are needed between the two adjacent electronic devices 13 to fix the two shielding covers 11 to the PCB 12 to form two shielding cavities for isolating the two electronic devices 13.

[0186] In the circuit board assembly shown in FIG. 5, the shielding film 340 is attached and formed, and the shielding film 340 does not need to be arranged on the PCB 310 in a fixed manner with the solder pad. In this case, the problem of how to isolate the two electronic devices 320 needs to be considered. In FIG. 5, the shielding film 340 can be separated into two shielding cavities by being electrically connected with a row of ground pads 370 between the first electronic device 320a and the second electronic device 320b, and used to cover the first electronic device 320a and the second electronic device 320b, respectively. It can be seen that, compared with the traditional shielding scheme shown in FIG. 3, the circuit board assembly 300 can only arrange a row of ground pads 370 between the two adjacent electronic devices 320 that need to be isolated, thereby having a layout area benefit and being conducive to miniaturization of the whole machine.

[0187] The above describes the difference between the novel board-level shielding integrated scheme shown in FIG. 5 and the traditional shielding scheme shown in FIG. 3. The difference between the circuit board assembly formed by the board-level film covering shielding scheme shown in FIG. 4 and the circuit board assembly in FIG. 5 will be described in conjunction with FIGS. 9 to 18.

[0188] Difference one: compared with the circuit board assembly formed by the board-level film covering shielding scheme shown in FIG. 4, the insulating film 330 in the circuit board assembly shown in FIG. 5 can extend to the gap around the device body 321 to cover the electronic device 320.

[0189] Specifically, please refer to FIG. 9, which is a film material filling diagram of the circuit board assembly 20 formed by the board-level film covering shielding scheme shown in FIG. 4.

[0190] Because the environment of the electronic device 24 on the PCB 23 is complex, the height difference is large (for example, the height of the IC is low, and the height of the RLC is high), and the layout density is high (the minimum spacing is 0.1 mm), the semi-cured insulating film 21 and the shielding film 22 are used for hot pressing, and the tensile property, flowability and strength of the film material need to be considered. Therefore, the filling property of the circuit board assembly 20 in the small gap around the device (for example, the small gap between the devices shown in the region S1 and the small gap at the bottom of the device shown in the region S2) is poor (the insulating film 21 cannot be completely attached to the surface of the electronic device 24 corresponding to the small gap around the device), and even the insulating film 21 cannot extend into the small gap around the device, so that the electronic device 24 cannot be covered.

[0191] It can be understood that, in the case that the filling property of the insulating film 21 in the small gap around the device is poor, the insulating film 21 is easily peeled off from the surface of the electronic device 24 due to the influence of factors such as thermal expansion and cold contraction, thereby causing reliability problems such as peeling and delamination of the film material and rupture of the film material in the application environment. It should be noted that, due to factors such as material (the shielding film 22 and the insulating film 21 are both high molecular materials, and the electronic device 24 can be a silicon-containing material) and contact area, the shielding film 22 and the insulating film 21 have strong adhesion to each other, and are not easy to be peeled off from the surface of the insulating film 21.

[0192] In view of the poor filling of the insulating film 21 in the small gap between devices in FIG. 9, please refer to FIG. 10, which is a schematic diagram of the structure of the insulating film 330 in the circuit board assembly shown in FIG. 5. It shows the filling of the insulating film 330 in the gap between the electronic devices 320. Among them, the insulating film 330 can extend into the gap between the electronic devices 320, and extend along the side of the corresponding gap of the electronic devices 320 to the bottom surface of the device body 321 of the electronic devices 320 respectively, so as to at least cover the device body 321 of each electronic device 320 respectively.

[0193] FIG. 10 shows two adjacent electronic devices 320, namely the first electronic device 320a and the second electronic device 320b. The following will be described in detail taking the gap between the first electronic device 320a and the second electronic device 320b as an example.

[0194] Optionally, the width L of the gap between the first electronic device 320a and the second electronic device 320b is 1 um-50 um. In this case, it can be considered that there is a small gap between devices between the first electronic device 320a and the second electronic device 320b.

[0195] The insulating film 330 can extend into the gap between the first electronic device 320a and the second electronic device 320b, and extend along the side of the corresponding gap of the first electronic device 320a and the second electronic device 320b to the bottom surface of the device body (hereinafter referred to as the first device body 321a) of the first electronic device 320a and the bottom surface of the device body (hereinafter referred to as the second device body 321b) of the second electronic device 320b respectively, so as to cover the first electronic device 320a and the second electronic device 320b respectively.

[0196] It should be noted that the side of the corresponding gap of the first electronic device 320a and the second electronic device 320b, i.e. the side of the first electronic device 320a and the second electronic device 320b facing each other.

[0197] In this embodiment, because the insulating film 330 extends along the side of the corresponding gap of the first electronic device 320a and the second electronic device 320b to the bottom surface of the first device body 321a and the second device body 321b, the attachment area is larger, and the filling of the gap between the two adjacent electronic devices 320 is better.

[0198] And, the insulating film 330 extends to the bottom surface of the first device body 321a and the bottom surface of the second device body 321b at the side of the gap corresponding to the first electronic device 320a and the second electronic device 320b, respectively, and is inevitably attached to the side of the gap corresponding to the first electronic device 320a and the second electronic device 320b and the bottom surface of the first electronic device 320a and the second electronic device 320b. By being attached to the side of the gap corresponding to the first electronic device 320a and the second electronic device 320b and the bottom surface, a stronger pulling force can be formed between the first electronic device 320a and the second electronic device 320b. In addition, the insulating film 330 has a large attachment area by covering the entire first electronic device 320a and the second electronic device 320b, so that the insulating film 330 can be more firmly attached to the surface of the first electronic device 320a and the second electronic device 320b without reliability problems such as peeling, film rupture, etc., thereby improving the reliability of the circuit board assembly 300 in the application environment.

[0199] Of course, in other embodiments, the insulating film 330 can also cover the first device body 321a and the second device body 321b, respectively, without covering the connecting end 322b of the first electronic device 320a and the connecting end 322b of the second electronic device 320b. That is, in the specific implementation process, the insulating film 330 is used to cover the first device body 321a and the second device body 321b, respectively. The present application does not make special limitation to this.

[0200] It should be noted that, since the film coating process converts the thin film material into gaseous atoms, molecules or ions and deposits them on the surface of the electronic device 320, it has low requirements for the gap around the device and has strong penetration effect. In addition, it does not need to consider the tensile property, flowability and strength of the film material because it does not need to press the film material. The insulating film 330 formed by the film coating process can extend to the small gap between the first electronic device 320a and the second electronic device 320b for conformal coating, and has good filling property in the small gap between the devices, thereby reducing the risk of reliability problems such as peeling, film rupture, etc. of the insulating film 330.

[0201] On the contrary, it can be understood that the insulating film 330 formed by the film coating process has good filling property in the small gap between the devices, so the film coating process has lower requirements for the gap between the two adjacent electronic devices 320 to be isolated.

[0202] Please refer to Fig. 11, which is a schematic diagram of the gap required for the insulating film 21 in the circuit board assembly 20 formed by the board-level film-coating shielding scheme shown in Fig. 4. In the embodiment shown in Fig. 11, the insulating film 21 is formed by a hot-pressing process. In order to make the insulating film 21 formed by the hot-pressing process fill the gap between the electronic devices 24, the width B of the gap between the electronic devices 24 is required to be at least 0.5 mm, so that the insulating film 21 can be better filled between the electronic devices 24, which is not conducive to the high-density and small-size design of the PCB. In the embodiment shown in Fig. 10, the film-coating process has a lower requirement for the gap between the electronic devices, for example, it can achieve better filling in the small gap between the electronic devices with a gap width of 1 um to 50 um, which is conducive to the high-density and small-size design of the PCB 310.

[0203] Of course, in other embodiments, if other processes can make the insulating film 330 extend along the surface of the electronic device 320 to the small gap between the adjacent two electronic devices 320 to be isolated, it is also within the protection scope of the embodiments of the present application.

[0204] In view of the poor filling of the insulating film 21 in the small gap at the bottom of the electronic device in Fig. 9, please continue to refer to Fig. 10, which shows the filling of the insulating film 330 in the gap at the bottom of the electronic device 320.

[0205] Among them, the insulating film 330 formed by the film-coating process can extend along the surface of the electronic device 320 to the bottom surface of the device body 321, so as to achieve the filling of the gap at the bottom of the electronic device 320.

[0206] It should be noted that, because the film-coating process converts the thin film material into gaseous atoms, molecules or ions and deposits them on the surface of the electronic device 320, it has a low requirement for the gap around the device and has a strong penetration effect, in addition, it does not need to consider the tensile property, flowability and strength of the film material because it does not need to compress the film material, so the insulating film 330 formed by the film-coating process is more likely to extend to the bottom surface of the device body 321 of the electronic device 320 for conformal coating, and has better filling property in the small gap at the bottom of the device.

[0207] Of course, in other embodiments, if other processes can make the insulating film 330 extend along the surface of the electronic device 320 to the bottom surface of the device body 321, at least to coat the device body 321 of the electronic device 320, it is also within the protection scope of the embodiments of the present application.

[0208] It can be understood that the insulating film 330 extends along the surface of the electronic device 320 to the bottom surface of the device body 321 to wrap the electronic device 320, which will inevitably be attached to the side surface of the electronic device 320 and the bottom surface of the electronic device 320. The part attached to the side surface and the bottom surface of the electronic device 320 can form a stronger pulling force with the electronic device 320. In addition, the insulating film 330 has a larger attachment area by wrapping the entire electronic device 320, so that the insulating film 330 can be more firmly attached to the surface of the electronic device 320 without easily delaminating, film material cracking and other reliability problems, thereby improving the reliability of the circuit board assembly 300 in the application environment.

[0209] Next, for different types of electronic devices 320, the requirements of the plating film process for the gap at the bottom of the device are described.

[0210] Exemplarily, please refer to FIG. 12, which is a schematic diagram of the related structure of the circuit board assembly shown in FIG. 5, in which the insulating film 330 wraps the chip.

[0211] In the embodiment shown in FIG. 12, the electronic device 320 is a chip IC. For the sake of distinction and description, the device body 321 of the IC is referred to as a chip body 3211 in this application, and the chip body 3211 is electrically connected to the device pad 350 on the PCB 310 through the connecting end 322 at the bottom of the chip body 3211. The connecting end 322 at the bottom of the chip body 3211 is referred to as the chip solder end 3221 in this application, and the device pad 350 on the PCB 310 electrically connected to the chip is referred to as the chip pad 351. That is, the chip body 3211 is electrically connected to the chip pad 351 on the PCB 310 through the plurality of chip solder ends 3221 at the bottom of the chip body 3211.

[0212] In the case where the IC meets at least one of the following four conditions, it can be considered as an electronic device 320 with a small gap at the bottom of the device. For such ICs, the insulating film 330 can be extended to the bottom surface of the chip body 3211 on the surface of the IC to wrap the IC and achieve good filling of the small gap at the bottom of the chip by using the plating film process.

[0213] Condition one: the bottom gap H1 of the chip satisfies 10um≤H1≤150um;

[0214] Condition two: the re-entrant size W1 of the chip solder end 3221 is ≥100um;

[0215] Condition three: the diameter D1 of the chip solder end 3221 satisfies 150um≤D1≤300um;

[0216] Condition four: the center distance D2 between the two adjacent chip solder ends 3221 satisfies 300um≤D2≤600um.

[0217] It can be understood that the bottom gap H1 of the chip refers to the distance between the bottom surface of the chip body 3211 and the upper surface of the PCB 310; the inner recess size W1 of the chip solder end 3221 refers to the shortest distance between the plane where the side surface of the chip body 3211 is located and the surface of the chip solder end 3221; and the center distance D2 of the adjacent two chip solder ends 3221 refers to the distance between the centers of the adjacent two chip solder ends 3221.

[0218] It can be understood that FIG. 12 is an illustration made in the case of the chip solder end 3221 being a solder ball. In other embodiments, for the case of the chip solder end 3221 not being a solder ball, the above-mentioned condition three is that the height D1 of the chip solder end 3221 in the Z-axis direction satisfies 150um≤D1≤300um; and the above-mentioned condition four is that the distance between the geometric centers of the adjacent two chip solder ends 3221.

[0219] Of course, in some other embodiments, when the chip satisfies at least one of the above-mentioned conditions one to four, if other processes can make the insulating film 330 extend along the surface of the chip to the bottom surface of the chip body 3211, achieving good filling of the small gap at the bottom of the chip, it is also within the protection scope of the embodiments of the present application.

[0220] Exemplarily, please refer to FIG. 13, which is a schematic diagram of the related structure of the insulating film 330 covering the passive element in the circuit board assembly shown in FIG. 5.

[0221] In the embodiment shown in FIG. 13, the electronic device 320 is a passive element RLC, such as a resistor (R), an inductor (L) and a capacitor (C). For the convenience of distinguishing and illustrating, the device body 321 of the RLC is referred to as an element body 3212 in the present application. The element body 3212 is electrically connected to the device pad 350 on the PCB 310 through the connecting end 322 at the bottom of the element body 3212. The connecting end 322 at the bottom of the element body 3212 is referred to as an element solder end 3222 in the present application, and the device pad 350 on the PCB 310 electrically connected to the RLC is referred to as an element pad 352. That is, the element body 3212 is electrically connected to the element pad 352 on the PCB 310 through the element solder end 3222 at the bottom of the element body 3212.

[0222] For the case of the electronic device 320 being an RLC, in the case of the bottom gap H2 of the RLC≤30um (condition one) and / or the inner recess size W2 of the element solder end 3222 of the RLC≥30um (condition two), the electronic device 320 with a small gap at the bottom of the device can be considered. For such RLC, the insulating film 330 can be extended to the bottom surface of the element body 3212 on the surface of the passive element by using a plating process to cover the RLC, achieving good filling of the small gap at the bottom of the passive element.

[0223] It can be understood that the bottom gap H2 of the passive component refers to the distance between the bottom surface of the component body 3212 and the upper surface of the PCB 310; the inner recess dimension W2 of the component solder end 3222 refers to the shortest distance between the plane where the side surface of the component body 3212 is located and the surface of the component solder end 3222.

[0224] Of course, in some other embodiments, when the passive component meets the above condition one and / or condition two, if other processes can make the insulating film 330 extend along the surface of the passive component to the bottom surface of the component body 3212, achieving good filling of the small gap at the bottom of the passive component, it is also within the protection scope of the embodiments of the present application.

[0225] Difference two: compared with the circuit board assembly formed by the board-level film-coating shielding scheme shown in FIG. 4, the insulating film 330 in the circuit board assembly 300 shown in FIG. 5 can be attached to the surface of the connecting end 322.

[0226] Specifically, still referring to FIG. 9, the filling property of the insulating film 21 at the small gap at the bottom of the device is poor, so that it cannot extend to the surface of the device solder ball 242 located at the bottom of the device body 241 to cover it, which makes the electronic device 24 prone to short circuit between the solder joints (the structure formed by the device solder ball 242 and the device pad 26), causing electrical failure.

[0227] For the electrical failure problem caused by the short circuit between the solder joints in FIG. 9, still referring to FIG. 10, the insulating film 330 extends from the bottom surface of the device body 321 to the surface of the connecting end 322, covering the connecting end 322 together, thereby achieving the covering of the entire electronic device 320. It can be understood that in this embodiment, the insulating film 330 covers the connecting end 322, which can not only play a role of underfilling glue, dispersing the stress of the connecting end 322, thereby improving the electrical connection reliability, but also achieve the purpose of insulating the connecting end 322 from the outside, thereby reducing the risk of short circuit between the solder joints.

[0228] It should be noted that the insulating film 330 formed by the film plating process can extend to the bottom of the device body 321, and naturally can also extend to the surface of the connecting end 322 located at the bottom of the device body 321, achieving the covering of the connecting end 322 at the bottom of the device. Of course, in some other embodiments, if other processes can make the insulating film 330 extend along the surface of the electronic device 320 to the surface of the connecting end 322 at the bottom of the device body 321, it is also within the protection scope of the embodiments of the present application.

[0229] Difference three: compared with the circuit board assembly formed by the board-level film-coating shielding scheme shown in FIG. 4, the insulating film 330 in the circuit board assembly shown in FIG. 5 has better adhesion at the recessed position of the device surface.

[0230] Specifically, please refer to Fig. 14, which is a schematic view of the insulating film 21 in the circuit board assembly 20 shown in Fig. 4 formed by the board-level film-coating shielding scheme at the position of the surface recess of the electronic device.

[0231] In Fig. 14, the electronic device 24 is a special recess electronic device, i.e., the electronic device 24 has a recess 243 on the surface. When the semi-cured insulating film 21 is pressed, the adhesion of the insulating film 21 at the recess 243 area is not firm due to the small pressure on the insulating film 21 (caused by the lower inner wall surface at the recess position of the surface of the special recess electronic device than the surrounding surface) and other factors, and the peeling and delamination of the insulating film 21 may occur due to thermal expansion and contraction and other factors.

[0232] For the case that the electronic device 24 in Fig. 14 is a special recess electronic device, exemplarily, please refer to Fig. 15, which is a schematic view of the related structure of the circuit board assembly shown in Fig. 5 involving the insulating film 330 covering the special recess electronic device 320.

[0233] In the embodiment shown in Fig. 15, the electronic device 320 is a special recess electronic device 320. It can be understood that although the special recess electronic device 320 in the figure is a passive device RLC, in other embodiments, the special recess electronic device 320 can also be an active device.

[0234] The surface of the special recess electronic device 320 has a groove 323, and the position of the groove 323 is the recess position of the surface of the special recess electronic device. The insulating film 330 formed by the film coating process extends along the surface of the special recess electronic device to the groove 323 and is attached to the inner wall surface of the groove 323. It can be understood that since the film coating process does not involve hot pressing of the film material using pressure, but forms the insulating film 330 by deposition, it is not easy to have the peeling and delamination of the insulating film 21 at the inner wall surface of the groove 323 due to the small pressure.

[0235] In the implementation process, when the groove width H3 of the groove 323 satisfies 100um≤H3≤700um (condition one) and / or the groove depth W3 of the groove is ≥20um (condition two), the film coating process can be used to realize that the insulating film 330 extends along the surface of the special recess electronic device to the groove and is attached to the inner wall surface of the groove, thereby realizing the conformal coating of the insulating film 330 on the special recess electronic device 320.

[0236] Of course, in other embodiments, when the special recess electronic device 320 satisfies the above condition one and / or condition two, if other processes can make the insulating film 330 conformally attached to the inner wall surface of the groove 323, it is also within the protection scope of the embodiments of the present application.

[0237] Difference four: compared with the circuit board assembly formed by the board-level film-coated shielding scheme shown in FIG. 4, the thickness of the insulating film 330 in the circuit board assembly shown in FIG. 5 is more uniform, which is beneficial to the electrical consistency design.

[0238] Specifically, please refer to FIG. 16, which is a schematic diagram of the thickness uniformity problem and short circuit risk of the circuit board assembly 20 formed by the board-level film-coated shielding scheme shown in FIG. 4.

[0239] In FIG. 16, the insulating film 21 is formed by a hot-pressing process. It should be noted that the thickness of the film layer formed by the hot-pressing process is strongly related to the height and layout density of the electronic device 24. For example, the thickness at the position shown in region S3 is quite different from the thickness at the position shown in region S4, which makes the thickness consistency of the insulating film 21 poor (the thickness difference at different positions exceeds 30 um).

[0240] It can be understood that the shielding film 22 and the electronic device 24 are distributed above and below, which constitutes a capacitor. The shielding film 22 and the electronic device 24 are respectively two electrode plates of the capacitor, and the thickness of the insulating film 21 between the shielding film 22 and the electronic device 24 is different, which makes the spacing between the two electrode plates of the capacitor inconsistent. The parasitic capacitance of the capacitor is related to the spacing between the two electrode plates. The thickness difference of the insulating film 21 at different positions is too large, which leads to the parasitic capacitance at different positions being too different. It should be noted that the existence of the parasitic capacitance leads to problems such as frequency point drift. The parasitic capacitance at different positions is too different, which makes the frequency point drift at different positions too different, which is not conducive to the electrical consistency design.

[0241] In view of the problem that the thickness consistency of the insulating film 21 formed by the hot-pressing process in FIG. 16 is poor and is not conducive to the electrical consistency design, please refer to FIG. 17, which is a schematic diagram of the related structure involving the thickness of the insulating film 330 in the circuit board assembly shown in FIG. 5.

[0242] In FIG. 17, since the insulating film 330 is formed by a plating process in the form of depositing thin film material, it does not involve the pressing and stretching of the film material by the hot-pressing process, and the thickness of the film layer of the insulating film 330 is not strongly related to the height and layout density of the electronic device 320. Therefore, the thickness of the insulating film 330 is more uniform.

[0243] Through testing, the thickness difference index T of the insulating film 330 is ≤10%. Wherein, T=(Ta-Tb) / Ta, Ta and Tb are the thicknesses of the insulating film 330 at any two positions.

[0244] For example, FIG. 17 shows the thickness of the insulating film 330 at different positions on the surfaces of the three devices, the chip IC, the passive element RLC, and the special recessed device RLC. For the insulating film 330 on the surface of the IC, Ta and Tb can be any two of the positions shown in T1 (the position of the insulating film 330 corresponding to the top surface of the IC), T2 (the position of the insulating film 330 corresponding to the sharp corner of the IC), T3 (the position of the insulating film 330 corresponding to the side surface of the IC), T4 (the position of the insulating film 330 corresponding to the bottom surface of the IC), and the like; for the insulating film 330 on the surface of the passive element RLC, Ta and Tb can be any two of the positions shown in T4 (the position of the insulating film 330 corresponding to the top surface of the passive element RLC), T5 (the position of the insulating film 330 corresponding to the top surface of the passive element RLC), T6 (the position of the insulating film 330 corresponding to the sharp corner of the passive element RLC), T7 (the position of the insulating film 330 corresponding to the side surface of the passive element RLC), T8 (the position of the insulating film 330 corresponding to the bottom surface of the passive element RLC), and the like; for the insulating film 330 on the surface of the special recessed device RLC, Ta and Tb can be any two of the positions shown in T9 (the position of the insulating film 330 corresponding to the top surface of the special recessed device RLC), T10 (the position of the insulating film 330 corresponding to the sharp corner of the special recessed device RLC), T11 (the position of the insulating film 330 corresponding to the recess of the special recessed device RLC), T12 (the position of the insulating film 330 corresponding to the side surface of the special recessed device RLC), T13 (the position of the insulating film 330 corresponding to the bottom surface of the special recessed device RLC), and the like.

[0245] It should be noted that the thickness difference index T is used to represent the thickness consistency of the insulating film 330. The higher the thickness difference index T, the higher the thickness consistency of the insulating film 330; the lower the thickness difference index T, the lower the thickness consistency of the insulating film 330. It can be understood that the higher the thickness consistency of the insulating film 330, the more uniform the thickness of the insulating film 330.

[0246] In FIG. 16, the thickness of the insulating film 21 formed by the hot-pressing process is generally 50-150 um, and in the case where the thickness difference at different positions exceeds 30 um, the thickness difference index T of the insulating film 21 is at least 20%. Obviously, the thickness uniformity of the insulating film 330 shown in FIG. 17 is better, and the thickness is more uniform, which is beneficial to the electrical consistency design.

[0247] Difference five: the insulating film 330 in the circuit board assembly 300 shown in FIG. 5 is thinner than that obtained by using the board-level film shielding scheme shown in FIG. 4.

[0248] Please continue to refer to Figure 16, the thickness of the film layer formed by the hot pressing process is strongly related to the height of the electronic device and the layout density. For example, it is thinner at the position with larger height difference of the device (as shown in the position of region S3), and it is thicker at the position with smaller height difference of the device (as shown in the position of region S4). It can be understood that, in order to reduce the risk of film material rupture, the thickness of the film layer formed by the hot pressing process also needs to meet the standard at the thinnest position, in which case the thickness of the film layer at other positions is too thick to achieve ultra-thin, otherwise there is a risk of tensile rupture. According to tests, the thickness of the insulating film formed by the hot pressing process is usually 50um-150um, for example, the thickness of the position shown in region S3 is 80um, and the thickness of the position shown in region S3 is 130um. Obviously, the insulating film 330 and the shielding film 340 formed by the hot pressing process cannot achieve ultra-thin, which is not conducive to the thinning of the circuit board assembly.

[0249] In the embodiment shown in Figure 17, the thickness of the insulating film 330 formed by the plating process is uniform, and there is no need to deliberately thicken the insulating film in order to prevent the film layer from being easily broken at the thinnest position. In addition, the film layer thickness of nanometer to micrometer can be achieved, so that the insulating film 330 can achieve ultra-thin when the insulating film 330 is formed by the plating process, thereby facilitating the overall thinning of the circuit board assembly. In addition, it can be understood that, because the plating process can make the insulating film 330 ultra-thin, the space reserved for the shielding film 340 is more, so in the circuit board assembly shown in Figure 5, even if the hot pressing process is used, the shielding film 340 has better filling performance at the bottom of the device and between the devices.

[0250] Optionally, the thickness of the insulating film 330 formed by the plating process at any position can be 0.5um-40um. The thickness range of 0.5um-40um makes it less likely to have a short circuit risk between the shielding film 340 and the electronic device 320, while the insulating film formed by the hot pressing process is thinner, which has a thickness benefit.

[0251] It should be noted that the thickness range of 0.5um-40um here is intended to indicate the order of magnitude that the thickness of the insulating film 330 formed by the plating process can reach, and does not represent that the thickness of the insulating film 330 formed by the plating process at different positions is a value with a large difference in the thickness range of 0.5um-40um.

[0252] In combination with the foregoing, the thickness of the insulating film 330 formed by the film plating process on different positions of the same circuit board assembly is not the same, but the difference is small, and the thickness difference index T is less than or equal to 10%. For example, the thickness of the insulating film 330 at T1, T2, T6, T7, and T11 in FIG. 17 is 20.5 um, 20 um, 20.1 um, 20.4 um, and 20.3 um, respectively, but all fall within the thickness range of 0.5 um to 40 um. The thickness of the insulating film 330 formed by the film plating process on different circuit board assemblies can be quite different. For example, the thickness of the insulating film 330 formed by the film plating process on some circuit board assemblies is 39 um to 40 um, which also falls within the thickness range of 0.5 um to 40 um. The thickness of the insulating film 330 formed by the film plating process on some circuit board assemblies is 25 um to 26.7 um, which also falls within the thickness range of 0.5 um to 40 um, and so on.

[0253] Difference six: compared with the circuit board assembly obtained by using the board-level film covering shielding scheme shown in FIG. 4, the circuit board assembly 300 shown in FIG. 5 is less likely to have a short circuit risk between the shielding film 340 and the electronic device 320.

[0254] Specifically, please continue to refer to FIG. 16. Because the environment of the electronic device 24 on the PCB 23 is complex and has a large height difference (the highest is 1.2 mm and the lowest is 0.2 mm), the insulating film 21 will have a large tensile deformation when it is formed by using the hot pressing process, which will cause the insulating film 21 to be thinned to penetrate at the sharp corner positions of the electronic device 24 (such as the regions S5 and S6 shown in the figure), thereby causing a short circuit risk between the shielding film 22 and the electronic device 24, which is likely to cause electrical failure.

[0255] In view of the problem that the insulating film 21 formed by the hot pressing process in FIG. 16 is thinned or even penetrated at the sharp corner positions of the electronic device 24, please continue to refer to FIG. 17. Because the insulating film 330 is formed by the film plating process, it will not involve the stretching of the film material by the hot pressing process, and it will naturally be stretched at a large tensile rate at the sharp corner positions of the electronic device 320. In combination with the foregoing, the thickness difference index T of the insulating film 330 is less than or equal to 10%. It can be seen that the thickness of the insulating film 330 is more uniform, and there is no obvious thinning or even penetration at the sharp corner positions of the electronic device 320 (such as the positions shown in T2, T6, and T10). In this way, the shielding film 22 and the electronic device 24 are less likely to have a short circuit, and are also less likely to have electrical failure.

[0256] Difference seven: compared with the circuit board assembly obtained by using the board-level film covering shielding scheme shown in FIG. 4, the circuit board assembly 300 shown in FIG. 5 is less likely to have a problem of breaking of the insulating film 330.

[0257] Specifically, please refer to FIG. 18, which is a schematic diagram of the film rupture problem existing in the circuit board assembly 20 obtained by the board-level film-coating shielding scheme shown in FIG. 4.

[0258] Because of the complex environment and large height difference (the maximum height difference is 1.2 mm and the minimum height difference is 0.2 mm) of the electronic device 24 on the PCB 23, the film material is stretched greatly when being formed by the hot-pressing process, which leads to the risk of film rupture of the film material under a large stretching rate. The film rupture of the insulating film 330 is shown in the area S7 in the figure. It can be understood that, in the case of the film rupture of the insulating film 330, there is a risk of short circuit between the shielding film 22 and the electronic device 24.

[0259] In view of the film rupture problem of the insulating film 21 formed by the hot-pressing process shown in FIG. 18, please continue to refer to FIG. 17. Because the insulating film 330 is formed by the film-coating process, the film material will not be stretched by the hot-pressing process, and thus the film rupture caused by a large stretching rate will not occur, so that the short circuit between the shielding film 22 and the electronic device 24 will not occur, and thus the electrical failure will not occur.

[0260] The above description in combination with FIGS. 5 to 18 compares and describes the new board-level shielding integration scheme of the insulating film 330 formed by the film-coating process and the shielding film 340 formed by the hot-pressing process, and the board-level film-coating shielding scheme of the insulating film 330 and the shielding film 340 formed by the hot-pressing process shown in FIG. 4.

[0261] It should be noted that, because the shielding film 340 in the circuit board assembly shown in FIG. 5 is formed by the hot-pressing process, there are still a series of problems such as thickness uniformity, film rupture, and thick thickness caused by stretching. Based on this, another circuit board assembly adopting a new board-level shielding integration scheme is further provided based on the circuit board assembly shown in FIG. 5.

[0262] Exemplarily, please refer to FIG. 19, which is a structural schematic diagram of another circuit board assembly 300 provided by the embodiments of the present application. FIG. 19 can be understood as another cross-sectional view of the circuit board assembly 300 shown in FIG. 2 in the X-ZY plane.

[0263] The circuit board assembly 300 shown in FIG. 19 also adopts the new type of shielding integration scheme at the board level. In the circuit board assembly shown in FIG. 19, the insulating structure in the new type of shielding integration scheme is implemented by the insulating film 330 formed by a coating process, and the shielding structure is implemented by the shielding film 340 formed by a spraying process or a printing process. The following focuses on the shielding film 340 in the circuit board assembly shown in FIG. 19, which is different from the circuit board assembly shown in FIG. 5. The other contents in FIG. 19 (such as the differences compared with the conventional shielding scheme shown in FIG. 3 and the board-level film-coating shielding scheme shown in FIG. 4 and the resulting technical effects) can be adaptively referred to the related descriptions in FIGS. 5 to 18.

[0264] Compared with the shielding film 340 formed by the hot-pressing process in FIG. 5, in the circuit board assembly shown in FIG. 19, the shielding film 340 formed by the spraying process or the printing process is more likely to extend into the small gap at the bottom of the device. As shown in FIG. 19, the shielding film 340 is attached and extends to the area on the surface of the insulating film 330 corresponding to the non-connection region of the bottom surface of the device body 321 from the area on the surface of the insulating film 330 corresponding to the side surface of the electronic device 320, to the area on the surface of the insulating film 330 corresponding to the outer side surface of the connection end 322 from the area on the surface of the insulating film 330 corresponding to the non-connection region of the bottom surface of the device body 321, and to the area on the surface of the insulating film 330 corresponding to the outer side surface of the connection end 322 from the area on the surface of the insulating film 330 corresponding to the outer side surface of the connection end 322.

[0265] Here, the outer side surface of the connection end 322 refers to the surface of the connection end 322 facing the outer side (the side facing the side surface of the device body 321). In this way, the shielding film 340 does not extend between the solder joints, thereby reducing the risk of short circuit between the solder joints through the shielding film 340.

[0266] It should be noted that, compared with the shielding film 340 formed by the hot-pressing process in FIG. 5, since the spraying process and the printing process do not involve pressing the film material and thus do not need to consider the tensile property and strength of the film material, the shielding film 340 is formed by relying on the permeability of the flowability of the film material to the gap, and thus the shielding film 340 formed by the spraying process and the printing process is more likely to extend to the small gap at the bottom of the device body 321 and has a lower requirement for the gap at the bottom of the device. It can be understood that, when the shielding film 340 extends to the small gap at the bottom of the device, the insulating film 330 can be bound from more areas, thereby reducing the risk of delamination of the inner insulating film 330 from the surface of the electronic device 320. When the shielding film 340 has a lower requirement for the gap at the bottom of the device, it is beneficial to the thinness and miniaturization of the whole machine.

[0267] In the implementation process, when the spraying process or the printing process is used to form the shielding film 340, the shielding material used for the shielding film 340 can be a flowable material with conductive properties.

[0268] Exemplarily, the shielding material can be a flowing material containing metal. For example, a conductive ink or a conductive glue. The conductive ink can be a pure metal solution, such as a copper, silver or other metal solution. The conductive glue can be a mixture of resin and metal particles. The resin can be epoxy resin, PBO, PI, Parylene, PET, PTFE, TPU, FEP, PFA, HDPE, etc., and the metal particles can be any one of elemental metals such as copper, nickel, chromium, aluminum, silver, gold, etc., or a metal alloy. Exemplarily, the shielding material can also be a flowing material containing carbon material. The carbon material can be graphite, graphene, carbon nanotube, etc. For example, the shielding material can be a composite of carbon material and organic material, and can also be a composite of metal, carbon material and organic material, and the organic material makes the shielding material flowable.

[0269] Of course, in some other embodiments, the shielding film 340 formed by the spraying process or the printing process can also not extend to the bottom surface of the device body 321, and the embodiments of the present application do not limit this.

[0270] Compared with the shielding film 340 formed by the hot pressing process in FIG. 5, in the circuit board assembly shown in FIG. 19, the shielding film 340 formed by the spraying process or the printing process is more likely to extend into the small gap between the devices, and the specific reasons can be referred to the reasons for the shielding film 340 being more likely to extend into the small gap at the bottom of the device. It can be understood that when the shielding film 340 extends into the small gap between the devices, the two adjacent electronic devices 320 to be isolated can be isolated, thereby reducing the electromagnetic interference between the two electronic devices 320.

[0271] On the contrary, the shielding film 340 formed by the spraying process or the printing process has lower requirements for the gap between the two adjacent electronic devices 320 to be isolated.

[0272] Please refer to FIG. 20 in combination, which is a schematic view of the gap required by the shielding film in the circuit board assembly 20 formed by the board-level film shielding scheme shown in FIG. 4. In the embodiment shown in FIG. 20, the shielding film 22 is formed by the hot pressing process. In order to make the shielding film 22 formed by the hot pressing process fill between the electronic devices 24, it is required that the width C of the gap between the electronic devices 24 in the insulating film 21 is at least 0.4 mm or more, so as to be better filled. Obviously, this is not conducive to the high-density and small-size design of the PCB. In the embodiment shown in FIG. 19, compared with the hot pressing process, the spraying process or the printing process has lower requirements for the gap between the electronic devices 320, and thus is conducive to the high-density and small-size design of the PCB 310.

[0273] Compared with the shielding film 340 formed by the hot-pressing process in FIG. 5, in the circuit board assembly shown in FIG. 19, the shielding film 340 is formed by spraying or printing the thin film material with fluidity, without involving the stretching of the film material by the hot-pressing process, and the thickness of the film layer of the insulating film 330 is not strongly related to the height and layout density of the electronic device 320. Therefore, the thickness of the shielding film 340 formed by the spraying or printing process is more uniform, and there is no need to deliberately thicken the film layer in order to prevent the film layer from being easily broken at the thinnest position. In this case, the shielding film formed by the spraying or printing process can be thinner, thereby facilitating the overall thinning of the circuit board assembly.

[0274] Optionally, the thickness of the shielding film 340 formed by the spraying or printing process at any position can be 2 um to 40 um. The thickness range of 2 um to 40 um makes the shielding film 340 less likely to have electromagnetic shielding leakage risk, and the shielding film 340 formed by the spraying or printing process is thinner than the shielding film 340 formed by the hot-pressing process, thereby having a thickness benefit.

[0275] Here, the thickness range of 2 um to 40 um is intended to indicate the order of magnitude that the thickness of the shielding film 340 formed by the spraying or printing process can reach, and does not mean that the thickness of the shielding film 340 formed by the spraying or printing process at different positions has a large difference in the thickness range of 2 um to 40 um. It should be noted that the thickness of the shielding film 340 at different positions on the same circuit board assembly is not the same, but the difference in the thickness of the shielding film 340 on the same circuit board assembly is small, for example, the thickness of the shielding film 340 on the same circuit board assembly at the top surface, side surface, sharp corner, and bottom surface of the electronic device 320 is 20.7 um, 20.2 um, 20.1 um, and 20.4 um, respectively. The difference in the thickness of the shielding film 340 on different circuit board assemblies can be large, for example, the thickness of the shielding film 340 on some circuit board assemblies is 37 um to 40 um, the thickness of the shielding film 340 on some circuit board assemblies is 2 um to 4 um, and so on.

[0276] Of course, in the case of improving the performance of the tool used in the hot-pressing process, the shielding film 340 formed by the hot-pressing process can also reach 2 um to 40 um, but the cost required is extremely high. Therefore, in the specific implementation process, the shielding film 340 is preferentially formed by the spraying or printing process. It should be noted that the thickness of the shielding film 340 is not strongly related to the parasitic capacitance, and therefore the circuit board assembly shown in FIG. 19 does not have a requirement for the uniformity of the thickness of the shielding film 340. Based on this, even if the uniformity of the thickness of the shielding film 340 formed by the spraying or printing process in the circuit board assembly shown in FIG. 19 is not as good as that of the shielding film 340 formed by the plating process, it can also meet the requirements.

[0277] Compared with the shielding film 340 formed by the hot-pressing process in FIG. 5, in the circuit board assembly shown in FIG. 19, the shielding film 340 formed by the spraying process and the printing process is naturally stretched at the sharp corner position of the electronic device 320 due to the absence of stretching of the film material. In combination with the foregoing, it can be known that the thickness of the shielding film 340 is more uniform, and there is no obvious thinning or even rupture at the sharp corner position, the position with large height difference of the device, and the like, and thus the risk of shielding leakage in the circuit board assembly shown in FIG. 19 is lower.

[0278] Of course, in other embodiments, other processes can also be used to obtain a shielding film 340 with the same characteristics of the shielding film 340 formed by the spraying process or the printing process, which is not limited in the embodiments of the present application.

[0279] For example, the other process can be a plating process. The shielding film 340 formed by the plating process can extend to the small gap at the bottom of the device and the small gap between devices, and the requirements for the gap at the bottom of the device and the gap between devices are lower, and the thickness is thinner and is not prone to thinning of the film material, rupture of the film layer, and the like. The specific reasons can be adaptively referred to the foregoing related description of forming the insulating film by the plating process. In this way, the shielding film 340 formed by the plating process can have the technical effects that the shielding film 340 extends to the small gap at the bottom of the device and the small gap between devices, the requirements for the gap at the bottom of the device and the gap between devices are lower, and the thickness is thinner and is not prone to thinning of the film material, rupture of the film layer, and the like. The specific technical effects can be adaptively referred to the foregoing related description of the shielding film 340 formed by the spraying process or the printing process, which will not be described here in detail.

[0280] In the implementation process, the plating process can be a sputtering process. When the sputtering process is used to form the shielding film 340, the material of the shielding film 340 can be any one of elemental metals such as copper, chromium, and nickel or a metal alloy.

[0281] Compared with the use of the spraying process or the printing process to form the shielding film 340, because the plating process relies on the deposition and growth of atomic-level materials, the permeability of the thin film material to the gap is stronger in the processing process, and thus it is easier to extend to the gap around the device. It is also easier to extend between the solder joints. In this case, other means need to be adaptively introduced to hinder its extension between the solder joints. Conversely, it can be understood that, compared with the plating process, the spraying process or the printing process relies on the fluidity of the material, and the permeability of the latter to the gap is weaker, and thus it is not easy to extend to the area between the solder joints. In addition, the shielding film 340 formed by the plating process is more uniform and thinner than the shielding film 340 formed by the spraying process or the printing process.

[0282] FIGS. 5 to 20 realize the new type of board-level shielding integration scheme in which the insulating structure adopts the insulating film 330 attached in the shape and the shielding structure adopts the shielding film 340 attached in the shape.

[0283] In addition, the embodiment of the present application also provides another circuit board assembly.

[0284] Exemplarily, please refer to FIG. 21, which is a structural schematic diagram of another circuit board assembly provided by the embodiment of the present application. FIG. 21 can be understood as another cross-sectional view of the circuit board assembly 300 shown in FIG. 2 in the XY plane. The circuit board assembly 300 shown in FIG. 21 also adopts the aforementioned novel board-level shielding integration scheme, and thus can also realize the filling of the bottom of the electronic device 320.

[0285] Different from the circuit board assembly shown in FIG. 5, in the circuit board assembly shown in FIG. 21, the insulating structure in the aforementioned novel board-level shielding integration scheme is implemented by the insulating glue 380, and the shielding structure is implemented by the connected conductive frame (also referred to as a conductive dam in the embodiment of the present application, and hereinafter the conductive dam will be taken as an example for description) 391 and the shielding film 392. That is, the insulating structure is the insulating glue 380, and the shielding structure includes the conductive dam 391 and the shielding film 392.

[0286] Firstly, the conductive dam 391 will be described.

[0287] The conductive dam 391 is formed on the surface of the PCB 310 on the side where the electronic device 320 is located (i.e. the upper surface of the PCB 310 shown in the figure), and encloses the side toward which the side surface of the electronic device 320 faces. The technical term “encloses” involved in the embodiment of the present application means that the annular structure forms a closed annulus (an annulus without a notch, and FIG. 22 shows a contrastive schematic diagram of an annulus without a notch (as shown in (a) of FIG. 22) and a closed annulus with a notch (as shown in (b) of FIG. 22)), so as to make a certain structure inside the closed annulus, and enclose it. It should be noted that the annular structure is not limited to a circular ring structure (i.e. the formed enclosing ring is a closed circular ring), but for example, can also be a square ring structure (i.e. the formed enclosing ring is a closed square ring), and the like.

[0288] For example, please refer to FIG. 23, which is a top view of the circuit board assembly 300 shown in FIG. 21. The figure shows the case that the conductive dam 391 is a square ring structure, and the closed square ring formed by the square ring structure of the conductive dam 391 encloses the electronic device 320 inside, so as to enclose it.

[0289] In this embodiment, the conductive dam 391 is located on the side of the electronic device 320, and the electronic device 320 is enclosed from the side of the electronic device 320. In this case, as shown in FIG. 23, the projection of the electronic device 320 on the PCB 310 is located within the projection of the conductive dam 391 on the PCB 310. It can be understood that the conductive dam 391 and the electronic device 320 shown in the top view of FIG. 23 are the projections of the conductive dam 391 and the electronic device 320 on the PCB 310, respectively.

[0290] It should be noted that when the conductive dam 391 encloses the electronic device 320, a gap is maintained between the conductive dam 391 and the side of the electronic device 320, so that the insulating glue 380 can be filled between the conductive dam 391 and the side of the electronic device 320 to achieve insulation.

[0291] In the implementation process, the conductive dam 391 can be formed on the surface of the PCB 310 by a dispensing process, specifically on the surface of the ground pad 370 on the surface of the PCB 310. The material of the conductive dam 391 can be conductive glue. The conductive glue can be a mixture of resin and metal particles. The resin can be epoxy resin, PBO, PI, Parylene, PET, PTFE, TPU, FEP, PFA, HDPE, etc., and the metal particles can be any one of elemental metals such as copper, nickel, chromium, aluminum, silver, gold, etc. or metal alloys. Of course, in other embodiments, the conductive dam 391 can also be formed by a spraying process or other processes.

[0292] Secondly, the insulating glue 380 is described.

[0293] The insulating glue 380 is filled in the conductive dam 391, and is distributed on the top surface of the electronic device 320 and bent to extend to the side surface of the electronic device 320, and is distributed on the side surface of the electronic device 320 and bent to extend to the bottom surface of the device body 321 and the surface of the connecting end 322, so as to cover the electronic device 320. Of course, in other embodiments, the insulating glue 380 can also not cover the connecting end 322. For ease of understanding and description, the surface of the insulating glue 380 in the region of the top surface of the electronic device 320 is referred to as the top surface of the insulating glue 380, and the surface of the insulating glue 380 in the region of the side surface of the electronic device 320 is referred to as the side surface of the insulating glue 380.

[0294] The technical term "filling" referred to in the embodiments of the present application refers to the state that the surface of the filler is attached to the surface of the filled object. In the embodiments, the side surface of the insulating colloid 380 is attached to the inner wall surface (the surface facing the side surface of the electronic device 320) of the conductive dam 391. In this case, the conductive dam 391 extends along the side surface of the insulating colloid 380 to the PCB 310, and specifically, the ground pad 370 of the PCB 310 is electrically connected to the ground pad 370 of the PCB 310. In this way, on the one hand, the conductive dam 391 can block the insulating colloid 380 during the filling of the insulating colloid 380 to prevent it from overflowing; on the other hand, the ground pad 370 is connected to the shielding film 392 through the conductive dam 391, so that the shielding film 392 can achieve the grounding purpose through the conductive dam 391, and the reliability of the grounding of the shielding film 392 can be improved.

[0295] In the implementation process, the insulating colloid 380 can be filled by a spraying process. When the spraying process is used for filling, the material of the insulating colloid 380 can be insulating glue. The insulating glue can be an organic material, an inorganic material, or an organic / inorganic composite material with insulating thermal properties, such as epoxy resin, PBO, PI, Parylene, PET, PTFE, TPU, FEP, PFA, HDPE, etc. Because the insulating glue has high fluidity, it can achieve complete filling without voids around the device (at the bottom of the device and between devices), thereby fully covering the electronic device 320 and increasing the strength of the circuit board assembly 300. Of course, in some other embodiments, the insulating colloid 380 can also be formed by a dispensing process or other processes.

[0296] It can be understood that because the conductive dam 391 is formed on the surface of the ground pad 370 and the insulating colloid 380 is filled in the conductive dam 391, the conductive dam 391 can be isolated from the electronic device 320 through the area between the ground pad 370 and the side surface of the electronic device 320 by the insulating colloid 380. In this way, the ground pad 370 does not need to avoid the electronic device 320 through a wider gap width as shown in FIG. 3, but can isolate the electronic device 320 and the conductive dam 391 through the thinner insulating colloid 380. Compared with the traditional scheme shown in FIG. 3, the circuit board assembly has a layout area benefit, which is conducive to the miniaturization of the whole machine.

[0297] Next, the shielding film 392 is described.

[0298] The shielding film 392 is attached to the top surface of the insulating colloid 380 and extends to the top end of the conductive dam 391 away from the PCB 310, and is electrically connected to the conductive dam 391. Specifically, the shielding film 392 extends to the top end of the conductive dam 391 to achieve electrical connection with the conductive dam 391 in the manner of being attached to the top end of the conductive dam 391.

[0299] It can be understood that, since the top surface of the insulating colloid 380 corresponds to the top surface of the electronic device 320, the shielding film 392 is naturally located on the side facing the top surface of the electronic device 320. At the same time, the conductive dam 391 is located on the side facing the side surface of the electronic device 320, and the top ends of the shielding film 392 and the conductive dam 391 are electrically connected to form a shielding cavity of the shielding structure, covering the electronic device 320 on the PCB 310.

[0300] In the implementation process, the shielding film 392 can be formed by any one of a spraying process, a printing process, and a plating process. It should be noted that, compared with the insulating film 330 shown in FIG. 5, the insulating colloid 380 formed by the spraying process has a greater thickness and occupies more space in the Z direction. Therefore, in order to compensate for the occupation of the Z direction space by the insulating colloid 380, the embodiment forms the shielding film 392 by the spraying process, the printing process, or the plating process. Compared with the hot-pressing process, the shielding film 392 formed by the spraying process, the printing process, or the plating process has a smaller thickness, thereby reducing the occupation of the Z direction space, and further facilitating the miniaturization and thinning of the terminal device. Of course, in some other embodiments, the shielding film 392 can also be formed by the hot-pressing process.

[0301] In the circuit board assembly shown in FIG. 21, the insulating colloid 380 is distributed on the top surface, the side surface, and the bottom surface of the electronic device 320, and the conductive dam 391 and the shielding film 392 are respectively located on the side surface of the insulating colloid 380 and the top surface of the insulating colloid, so that the insulating colloid 380 is interposed between the conductive structure formed by the shielding film 392 and the conductive dam 391 and the electronic device 320, and plays an insulating role. It can be seen that, unlike the shielding cover 11 shown in FIG. 3, the circuit board assembly no longer relies on the gap insulation, but relies on the insulating colloid 380 for insulation. It can be understood that the insulating effect of the insulating colloid 380 is higher than that of the gap in FIG. 3, which makes the insulating colloid 380 thinner (compared with the size of the gap) and attached to the surface of the electronic device 320. In the case that the insulating colloid 380 can be made thinner and the shielding film 392 and the conductive dam 391 are also attached to the surface of the insulating colloid 380, the shielding structure formed by the shielding film 392 and the conductive dam 391 can be closer to the electronic device 320 and cover the electronic device 320, which makes the height of the shielding structure lower than that of the shielding cover, thereby reducing the waste of space in the Z direction, and further facilitating the miniaturization and thinning of the terminal device.

[0302] In addition, in the circuit board assembly shown in FIG. 21, only one row of ground pads 370 can be arranged between two adjacent electronic devices 320 to be isolated. Unlike the circuit board assembly shown in FIG. 5, the shielding film 392 can be electrically connected to the row of ground pads 370 through the conductive dam 391 to form a first shielding cavity covering the first electronic device 320a and a second shielding cavity covering the second electronic device 320b.

[0303] Compared with the traditional shielding scheme of arranging two rows of ground pads 370 in FIG. 3, the circuit board assembly 300 can arrange only one row of ground pads 370 between two adjacent electronic devices 320 to be isolated, thereby having a layout area benefit and facilitating the miniaturization of the whole machine. The specific reasons can be adaptively referred to the related description in FIG. 5.

[0304] The above describes the difference between the novel board-level shielding integrated scheme shown in FIG. 21 and the traditional shielding scheme shown in FIG. 3. It can be understood that, because the insulating glue 380 can realize the complete filling without voids around the electronic devices (the bottom of the electronic device and between the electronic devices) and fully cover the electronic devices 320, the insulating glue 380 is not prone to the reliability problems such as peeling and delamination in FIG. 4, thereby the reliability of the circuit board assembly in the board-level application environment can be improved. The specific reasons can be adaptively referred to the related analysis in FIG. 5, which will not be described herein.

[0305] In some embodiments of the present application, please continue to refer to FIG. 21, the ratio of the wall height b and the wall width a of the conductive dam 391 is 2.4-6. For example, the ratio of the wall height b and the wall width a of the conductive dam 391 can be 2.4, 3.1, 3.8, 4.3, 5.5, 6. The wall height b of the conductive dam 391 is the height of the conductive dam 391 in the Z direction, and the wall width a of the conductive dam 391 is the thickness of the conductive dam 391 in the X direction. The wall width a of the conductive dam 391 is related to the width of the ground pad 370 connected by the conductive dam 391, and the wall height b of the conductive dam 391 is related to the electronic device 320 enclosed by the conductive dam 391. The specific value of the ratio of the wall height b and the wall width a of the conductive dam 391 is determined according to the ratio of the height of the electronic device 320 enclosed by the conductive dam 391 and the width of the ground pad 370, and can be floated up and down on the basis of the ratio of the height of the electronic device 320 enclosed by the conductive dam 391 and the width of the ground pad 370. The ratio should not be too large, otherwise it is prone to collapse and cannot be formed during processing.

[0306] The above embodiments describe the structure of the circuit board assembly formed by the novel board-level shielding integrated scheme. The processing method of the circuit board assembly formed by the novel board-level shielding integrated scheme is exemplarily described below.

[0307] Exemplarily, please refer to FIG. 24, which is a flow chart of a processing method of a circuit board assembly provided by an embodiment of the present application, including the following steps S2401 to S2403:

[0308] In step S2401, the electronic device is electrically connected to the PCB.

[0309] Step S2402, forming an insulating structure on the side of the PCB where the electronic device is located, so that the insulating structure extends from the surface of the electronic device to the bottom surface of the device body of the electronic device, to at least cover the device body;

[0310] Step S2403, forming a shielding structure on the side of the PCB where the electronic device is located, so that the shielding structure extends from the surface of the insulating structure to the PCB, to cover the electronic device, to obtain a circuit board assembly.

[0311] Step S2403 is after step S2402, only represents that the shielding structure in step S2403 is formed after the insulating structure in step S2402, but does not represent that the forming process of the shielding structure in step S2403 starts before the forming process of the insulating structure in step S2402, which is embodied in subsequent embodiments.

[0312] Next, the processing method of the circuit board assembly shown in FIG. 5 and the circuit board assembly shown in FIG. 21 will be described respectively.

[0313] First, the circuit board assembly shown in FIG. 5 will be described.

[0314] Exemplarily, please refer to FIG. 25 and FIG. 26, FIG. 25 is a flow chart of the processing method of the circuit board assembly 300 shown in FIG. 5 provided by the embodiment of the present application, and FIG. 26 is a structure process flow chart corresponding to the processing method shown in FIG. 25. The processing method of the circuit board assembly shown in FIG. 25 includes steps S2501 to S2507:

[0315] Step S2501, electrically connecting the electronic device 320 to the PCB 310.

[0316] For example, as shown in (a) of FIG. 26, the electronic device 320 (such as the IC and RLC shown in the figure) can be electrically connected to the PCB 310 in a surface mounting technology (Surface Mounted Technology, SMT) or the like.

[0317] It can be understood that the related content of step S2501 can be understood as a refinement of step S2401.

[0318] Step S2502, cleaning the surface of the PCB 310 and the electronic device 320.

[0319] For example, as shown in (b) of FIG. 26, the surface of the PCB 310 and the electronic device 320 can be cleaned by plasma. Through this step, the dirt on the surface of the PCB 310 and the electronic device 320 can be removed, and the hydrophilicity can be improved.

[0320] In the implementation process, the water droplet angle of the PCB 310 and the surface of the electronic device 320 is targeted to be 20°-30° for cleaning. It should be noted that the water droplet angle is the angle between the gas-liquid interface and the solid-liquid interface at the solid-liquid-gas three-phase junction. The higher the water droplet angle, the higher the hydrophilicity, and the surface is easier to stick; the lower the water droplet angle, the higher the hydrophobicity, and the surface is not easy to stick.

[0321] Step S2503, forming an insulating film 330 attached to the surface of the electronic device 320.

[0322] For example, as shown in (c) of FIG. 26, a plating process (such as CVD or PVD) can be used to deposit and form an insulating film 330 on the surface of the electronic device 320. The insulating film 330 formed by the plating process can be attached to the surface of the electronic device 320, with a thickness of 0.5um-40um and good thickness uniformity.

[0323] It can be understood that the insulating film 330 is used as the insulating structure of step S2402 in FIG. 24. Step S2503 can be understood as a refinement of step S2402.

[0324] Step S2504, windowing the insulating film 330 to expose the grounding area of the grounding pad 370.

[0325] For example, as shown in (d) of FIG. 26, the insulating film 330 can be windowed by laser windowing or the like to expose the grounding area of the grounding pad 370.

[0326] It should be noted that in (c) of FIG. 26, the insulating film 330 is integrally laid on the side where the electronic device 320 is located, not only attached to the surface of the electronic device 320, but also attached to the surface of the PCB not occupied by the electronic device 320, so the insulating film 330 will cover the grounding pad 370 laid on the surface of the PCB. Therefore, the insulating film 330 needs to be windowed here to expose the grounding pad 370, so as to facilitate the subsequent electrical connection with the shielding film 340.

[0327] Step S2505, cleaning the surface of the insulating film 330.

[0328] For example, as shown in (e) of FIG. 26, the surface of the insulating film 330 can be cleaned by Plasma. Through this step, the dirt on the surface of the PCB 310 and the electronic device 320 can be removed, and the hydrophilicity can be improved. In the implementation process, the water droplet angle of the PCB 310 and the surface of the electronic device 320 is targeted to be 20°-30° for cleaning.

[0329] Step S2506, forming a shielding film 340 attached to the surface of the insulating film 330 by a hot pressing process.

[0330] For example, as shown in (f) of FIG. 26, for the circuit board assembly shown in FIG. 5, a semi-cured conductive adhesive can be used to form the to-be-cured shielding film on the surface of the insulating film 330 by a hot-pressing process. The to-be-cured shielding film 340 formed by the hot-pressing process has a thickness of 15 μm to 100 μm.

[0331] In a specific implementation, the to-be-cured shielding film 340 can be formed by pressing under a high temperature (60°C to 180°C), a vacuum degree (10-2 Pa to 10-3 Pa), and a high pressure (1 MPa to 2 MPa). In (f) of FIG. 26, the to-be-cured shielding film 340 extends along the surface of the insulating film 330 to the ground pad 370 on the PCB 310 and is bonded to the exposed ground area of the ground pad 370, thereby forming an electrical connection relationship.

[0332] It can be understood that the shielding film 340 herein is used as the shielding structure of step S2403 in FIG. 24, and the related content of step S2506 can be understood as a refinement of step S2403.

[0333] After the to-be-cured shielding film 340 is formed, the to-be-cured shielding film 340 can be cured to form the shielding film 340. In a specific implementation, the curing temperature can be 60°C to 180°C, and the curing time can be 0.5 h to 4 h.

[0334] Step S2507: forming a protection film 360 attached to the surface of the shielding film 340, to obtain the circuit board assembly shown in FIG. 5.

[0335] For example, as shown in (g) of FIG. 26, the protection film 360 can be formed on the surface of the shielding film 340 by a hot-pressing process, a spraying process, or a plating process, to obtain the circuit board assembly 300 shown in FIG. 5. The protection film 360 formed by the hot-pressing process can be attached to the surface of the shielding film 340, and has a thickness of 5 μm to 15 μm. Of course, in a specific implementation, the surface of the shielding film 340 can be cleaned before S2507, and the protection film 360 can be cured after S2507.

[0336] FIGS. 25 and 26 illustrate the processing method of the circuit board assembly shown in FIG. 5. It can be understood that for the circuit board assembly shown in FIG. 19, the processing method of the circuit board assembly shown in FIG. 19 and the processing method shown in FIG. 25 differ in step S2506, specifically: forming the shielding film 340 on the surface of the insulating film 330 by a spraying process or a printing process.

[0337] In the implementation, as shown in FIG. 27, FIG. 27 is a structural process diagram of the shielding film 340 of the circuit board assembly 300 shown in FIG. 19. In FIG. 27, the shielding material with the conductive property such as conductive glue or conductive ink can be used to form the to-be-cured shielding film 340 on the surface of the insulating film 330 by a spraying process or a printing process. The to-be-cured shielding film 340 does not extend between the connecting ends 322.

[0338] After the to-be-cured shielding film 340 is formed, the to-be-cured shielding film 340 can be cured to form the shielding film 340 with a thickness of 2 um to 40 um.

[0339] In the implementation, the curing temperature can be 60°C to 180°C, and the curing time can be 0.5 h to 4 h.

[0340] Secondly, the circuit board assembly shown in FIG. 21 is taken as an example for description.

[0341] Exemplarily, referring to FIG. 28 and FIG. 29, FIG. 28 is a flow chart of the processing method of the circuit board assembly 300 shown in FIG. 21, and FIG. 29 is a structural process flow chart corresponding to the processing method shown in FIG. 28. The processing method of the circuit board assembly shown in FIG. 28 includes steps S2801 to S2806:

[0342] In step S2801, the electronic device 320 is electrically connected to the PCB 310, as shown in (a) of FIG. 29.

[0343] In step S2802, the surface of the PCB 310 and the electronic device 320 is cleaned, as shown in (b) of FIG. 29.

[0344] In step S2803, the conductive dam 391 is formed on the surface of the PCB 310, so that the conductive dam 391 is enclosed on the side where the electronic device 320 faces.

[0345] For example, as shown in (c) of FIG. 29, the to-be-cured conductive dam 391 can be formed on the surface of the PCB 310 by using the conductive glue and by a dispensing process. In the implementation, the to-be-cured conductive dam 391 is formed on the surface of the ground pad 370 on the surface of the PCB 310, so that the to-be-cured conductive dam 391 is electrically connected to the ground pad 370.

[0346] After the to-be-cured conductive dam 391 is formed, the to-be-cured conductive dam 391 can be cured to form the conductive dam 391. In the implementation, the curing temperature can be 60°C to 180°C, and the curing time can be 0.5 h to 4 h.

[0347] It can be understood that the conductive dam 391 is formed on the surface of the PCB 310 on the side where the electronic device 320 is located (i.e. the upper surface of the PCB 310 shown in the figure), so as to enclose the side of the device body 321. The conductive dam 391 is formed on the surface of the PCB 310, and naturally extends to the PCB 310.

[0348] In step S2804, the insulating glue 380 is filled in the conductive dam 391, so that the insulating glue 380 is wrapped around the electronic device 320 as an insulating structure.

[0349] The meaning that the insulating glue 380 wraps the electronic device 320 can refer to the related description in the foregoing FIG. 20, which will not be repeated here.

[0350] For example, as shown in (d) of FIG. 29, the conductive glue with fluidity can be filled into the conductive dam 391 by a spraying process to form the insulating glue 380 to be solidified.

[0351] In the implementation process, the height of the position where the insulating glue 380 to be solidified contacts the conductive dam 391 can not exceed the height of the conductive dam 391, so as to reduce the risk of overflow of the insulating glue 380 to be solidified at this position. It can be understood that in the case of overflow of the insulating glue 380 to be solidified at the position where it contacts the conductive dam 391, the top end of the conductive dam 391 away from the PCB 310 will be attached with insulating glue, so that the conductive dam 391 cannot form an electrical connection relationship with the shielding film 392 in the subsequent structure process shown in (e) of FIG. 29.

[0352] After the insulating glue 380 to be solidified is formed, the insulating glue 380 to be solidified can also be solidified to form the insulating glue 380. In the implementation process, the solidification temperature can be 60-180°C, and the solidification time can be 0.5-4h.

[0353] It can be understood that the related content of step S2804 can be understood as a refinement of step S2402.

[0354] In step S2805, the surface of the insulating glue 380 and the surface of the conductive dam 391 are cleaned.

[0355] For example, as shown in (e) of FIG. 29, the surface of the insulating film 330 and the surface of the conductive dam 391 can be cleaned by Plasma. The specific implementation can refer to the related description in (e) of FIG. 29.

[0356] In step S2806, the shielding film 392 is formed on the surface of the insulating gel 380 in a form of adhesion, and the shielding film 392 extends from the top surface of the insulating gel 380 to the top of the conductive dam 391, and is electrically connected with the conductive dam 391, thereby obtaining the circuit board assembly 300 shown in Fig. 21.

[0357] For example, as shown in (f) of Fig. 29, the shielding film 392 can be formed on the surface of the insulating gel 380 by using a spraying process or a plating process. The shielding film 392 formed by using the spraying process or the plating process has a uniform thickness, and the thickness is 2um-40um.

[0358] It should be noted that, when the spraying process is used to form the shielding film 392, the shielding film 392 to be solidified can be solidified after the spraying process is used to form the shielding film 392 to be solidified, and the shielding film 392 is formed. In the specific implementation process, the solidification temperature can be 60℃-180℃, and the solidification time can be 0.5h-4h.

[0359] It can be understood that the shielding film 392 and the conductive dam 391 electrically connected herein are used as the shielding structure in step S2403 of Fig. 24, and the related contents of step S2803 and step S2806 can be understood as a refinement of step S2403.

[0360] It should be noted that the embodiments shown in Figs. 24-28 roughly describe the processing method and process flow of the circuit board assembly, and the specific implementation and implementation effect can be adaptively referred to the description of the circuit board assembly in the foregoing related embodiments.

[0361] It should be understood that the sequence numbers of the steps in the processing method of the circuit board assembly in the embodiments shown in Figs. 24-28 do not mean the order of execution, and the execution order of the processes should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. In addition, the processing method of the circuit board assembly in the embodiments shown in Figs. 24-28 can also include more steps, and the embodiments of the present application do not make specific limitations.

[0362] Finally, it should be noted that in the description of the present application, the specific features, structures, etc. can be combined in any one or more embodiments or examples in a suitable manner. Moreover, the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A circuit board assembly, characterized by The application relates to an electronic device and a manufacturing method thereof. The electronic device comprises: a circuit board; an electronic device; the electronic device is electrically connected to the circuit board; an insulation structure; the insulation structure extends from the surface of the electronic device to the bottom surface of the device body of the electronic device to at least cover the device body; the bottom surface of the device body is the surface of the device body facing the circuit board; a shielding structure; 2. The circuit board assembly of claim 1, wherein, the shielding structure extends from the surface of the insulation structure to the circuit board to cover the electronic device. The device body is electrically connected to the circuit board through a connecting end located at the bottom of the device body; the bottom of the device body is the side of the device body facing the bottom surface; 3. The circuit board assembly of claim 1 or 2, wherein, the insulation structure further extends from the bottom surface of the device body to the surface of the connecting end to cover the connecting end.

4. The circuit board assembly of claim 3, wherein, The insulation structure is an insulation film which is attached to the top surface of the electronic device and extends to the side surface of the electronic device. The electronic device is a chip, and the device body of the chip is electrically connected to the circuit board through a plurality of chip welding ends; In the case of at least one of the following conditions, the insulation film at least extends to the bottom surface of the device body of the chip: the bottom gap H1 of the chip satisfies 10um<=H1<=150um; the retraction size W1 of the chip welding end is greater than or equal to 100um; the height D1 of the chip welding end satisfies 150um<=D1<=300um; 5. The circuit board assembly of claim 3 or 4, wherein, the center distance D2 of the adjacent two chip welding ends satisfies 300um<=D2<=600um. The electronic device is a passive element, and the device body of the passive element is electrically connected to the circuit board through a plurality of element welding ends; 6. The circuit board assembly of any one of claims 3 to 5, wherein, In the case of the bottom gap H2 of the passive element being less than or equal to 30um and / or the retraction size W2 of the element welding end being greater than or equal to 30um, the insulation film at least extends to the bottom surface of the device body of the passive element. The surface of the electronic device has a groove; 7. The circuit board assembly of any one of claims 3 to 6, wherein, In the case of the groove width H3 of the groove satisfying 100um<=H3<=700um and / or the groove depth W3 of the groove being greater than or equal to 20um, the insulation film is attached to the inner wall surface of the groove. The number of the electronic devices is plural, and there is a gap between the plural electronic devices; 8. The circuit board assembly of claim 7, wherein, The insulation structure extends into the gap and extends to the bottom surface of the device body of each electronic device along the side surface of each electronic device corresponding to the gap to at least cover the device body of each electronic device.

9. The circuit board assembly of any one of claims 3 to 8, wherein, The width of the gap is 1um-50um.

10. The circuit board assembly of any one of claims 3 to 9, wherein, The thickness difference index T of the insulation film is less than or equal to 10%; wherein T=(Ta-Tb) / Ta, Ta and Tb are the thicknesses of the insulation film at any two positions.

11. The circuit board assembly of any one of claims 3 to 10, wherein, The thickness of the insulation film at any position is 0.5um-40um.

12. The circuit board assembly of any one of claims 3 to 11, wherein, The insulation film is realized through a plating process.

13. The circuit board assembly of claim 12, wherein, The shielding structure is a shielding film which is attached to the surface of the insulation film and extends to the circuit board. The thickness of the shielding film at any position is 2um-40um.

14. The circuit board assembly of claim 1 or 2, wherein, The insulation structure is an insulation gel; the shielding structure comprises a conductive frame and a shielding film; The conductive frame is enclosed on a side towards which the electronic device side faces; The insulation gel is filled in the conductive frame, distributed on the top surface of the electronic device and extended to the side surface of the electronic device, and distributed on the side surface of the electronic device and extended to at least the bottom surface of the device body, a side towards which the bottom surface of the device body faces being the bottom surface of the device body; The inner wall surface of the conductive frame is attached to the side surface of the insulation gel and extended along the side surface of the insulation gel towards the circuit board; The shielding film is attached on the top surface of the insulation gel in a shape following the top surface of the insulation gel and extended to the top end of the conductive frame away from the circuit board and electrically connected to the conductive frame; wherein the side surface of the insulation gel is a region of the surface of the insulation gel corresponding to the side surface of the electronic device, and the top surface of the insulation gel is a region of the surface of the insulation gel corresponding to the top surface of the electronic device.

15. The circuit board assembly of claim 14, wherein, The ratio of the height of the wall body of the conductive frame to the width of the wall body is 2.4-6.

16. The circuit board assembly of claim 14 or 15, wherein, The insulation gel is formed by a spraying process.

17. The circuit board assembly of any one of claims 12 to 16, wherein, The shielding film is formed by any one of a spraying process, a printing process, a plating process and a hot pressing process.

18. The circuit board assembly of any one of claims 1 to 17, wherein, The shielding structure has a first shielding cavity and a second shielding cavity, the first shielding cavity is used for covering a first electronic device located on the circuit board, the second shielding cavity is used for covering a second electronic device located on the circuit board, the first electronic device and the second electronic device are two adjacent electronic devices on the circuit board; a row of grounding terminals is distributed between the first electronic device and the second electronic device; the shielding structure is electrically connected to the row of grounding terminals to form the first shielding cavity and the second shielding cavity.

19. A method of processing a circuit board assembly, characterized by, Comprise: electrically connecting an electronic device to a circuit board; forming an insulation structure on a side of the circuit board where the electronic device is located, so that the insulation structure extends from the surface of the electronic device to the bottom surface of the device body of the electronic device to at least cover the device body; forming a shielding structure on the side of the circuit board where the electronic device is located, so that the shielding structure extends from the surface of the insulation structure towards the circuit board to cover the electronic device, to obtain the circuit board assembly.

20. The method of claim 19, wherein the processing is performed by a computer. The forming of the insulation structure and the shielding structure on the side of the circuit board where the electronic device is located comprises: forming an insulation film attached on the surface of the electronic device in a shape following the surface of the electronic device, so that the insulation film at least covers the device body as the insulation structure; forming a shielding film attached on the surface of the insulation film in a shape following the surface of the insulation film, so that the shielding film extends on the surface of the insulation film towards the circuit board as the shielding structure.

21. The method of claim 20, wherein the processing is performed by a computer. The forming of the insulation film attached on the surface of the electronic device in a shape following the surface of the electronic device comprises: forming the insulation film on the surface of the electronic device by a plating process.

22. The method of claim 19, wherein the processing is performed by a computer. The forming of the insulation structure and the shielding structure on the side of the circuit board where the electronic device is located comprises: forming a conductive frame on the surface of the circuit board, so that the conductive frame is enclosed on a side towards which the electronic device side faces; Filling insulating glue in the conductive frame to form an insulating glue body; the insulating glue body covers at least the device body as the insulating structure; forming a shielding film attached in shape on the top surface of the insulating glue body, so that the shielding film extends from the top surface of the insulating glue body to the top end of the conductive frame away from the circuit board and is electrically connected with the conductive frame; wherein the shielding film and the conductive frame form the shielding structure.

23. The method of claim 22, wherein the processing is performed by a computer system. The filling insulating glue in the conductive frame comprises: filling the insulating glue in the conductive frame by a spraying process.

24. A method of processing according to any one of claims 20 to 23, wherein, The forming a shielding film attached in shape comprises: forming the shielding film attached in shape by any one of a spraying process, a printing process, a plating process and a hot pressing process.

25. A terminal device, comprising: comprises: a housing; The circuit board assembly of any one of claims 1 to 18 or the circuit board assembly processed by the method of any one of claims 19 to 24 is located in the housing.

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