A cavity-divided electromagnetic shielding structure, preparation method and electronic device

Abstract

The present invention discloses a cavity-divided electromagnetic shielding structure and a preparation method thereof. The preparation method includes: sequentially mounting chips on a substrate; arranging a shielding part between adjacent chips where there is electromagnetic interference; covering a thin film on the top of the shielding part and embedding the top of the shielding part into the thin film; filling a plastic encapsulation material between the thin film and the substrate to form a plastic encapsulation layer; removing the thin film so that the top of the shielding part protrudes from the plastic encapsulation layer; covering a metal material on the top of the shielding part and making the metal material contact with the top of the shielding part to form a conformal electromagnetic shielding layer. By covering the thin film above the shielding part, this preparation method avoids the processes of grinding or laser ablation on the shielding part, thus simplifying the processing procedures and improving the processing efficiency. Moreover, since the plastic encapsulation material is only encapsulated between the thin film and the substrate, the use of the plastic encapsulation material is reduced, and the overall production cost is lowered.

Description

Technical Field

[0001] The present invention relates to a cavity-divided electromagnetic shielding structure, and also relates to a preparation method of the cavity-divided electromagnetic shielding structure, and further relates to an electronic device including the cavity-divided electromagnetic shielding structure, belonging to the technical field of electromagnetic shielding. Background Art

[0002] With the continuous increase in the demand for electronic products, chip packaging technology has developed rapidly. The integration degree of chip packaging is getting higher and higher, and it is increasingly moving towards a system-in-package (SIP) structure. In the SIP structure, multiple radio frequency chips, analog chips or passive components are integrated together, and the distance between chips and devices is gradually reduced, resulting in an increasingly prominent electromagnetic interference (EMI) problem between devices in the SIP. Therefore, cavity-divided electromagnetic shielding structures are widely used.

[0003] In the US patent with the patent number US 11127689B2, a manufacturing method of a cavity-divided electromagnetic shielding structure is disclosed. By setting wire bonding wires between the devices to be shielded on a substrate, then plastic encapsulation and molding are carried out, and the wire bonding wires are exposed by means of surface grinding or laser ablation (laser ablation), and then a conformal shielding structure is set on the exposed wire bonding wires to complete the overall manufacturing process.

[0004] However, this method not only has complex processes, time-consuming and laborious. Moreover, grinding or laser ablation will consume a large amount of raw materials, resulting in waste of resources and increased production costs. Summary of the Invention

[0005] The primary technical problem to be solved by the present invention is to provide a preparation method of a cavity-divided electromagnetic shielding structure.

[0006] Another technical problem to be solved by the present invention is to provide a cavity-divided electromagnetic shielding structure.

[0007] Another technical problem to be solved by the present invention is to provide an electronic device.

[0008] To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0009] According to the first aspect of the embodiments of the present invention, a preparation method of a cavity-divided electromagnetic shielding structure is provided, including the following steps:

[0010] Mount chips on a substrate in sequence;

[0011] Set a shielding part between adjacent chips with electromagnetic interference;

[0012] Pre-cover a thin film on the injection mold, and cover the injection mold on the substrate so that the top of the shielding portion is embedded in the thin film;

[0013] Inject a plastic encapsulation material into the injection mold to form a plastic encapsulation layer;

[0014] Remove the injection mold to correspondingly remove the thin film, so that the top of the shielding portion protrudes from the plastic encapsulation layer;

[0015] Cover a metal material on the top of the shielding portion and make the metal material contact with the top of the shielding portion to form a conformal electromagnetic shielding layer.

[0016] Preferably, the step of arranging the shielding portion between adjacent chips with electromagnetic interference specifically includes:

[0017] Determine two adjacent chips or devices on the substrate with electromagnetic interference;

[0018] Arrange one or more wire bonding wires between the two adjacent chips, so that the one or more wire bonding wires block between the two adjacent chips or devices;

[0019] Repeat the above operations until wire bonding wires are arranged between all adjacent chips or devices on the substrate with electromagnetic interference.

[0020] Preferably, the number of the wire bonding wires is proportional to the electromagnetic interference intensity between two adjacent chips, and the distance between two adjacent wire bonding wires is inversely proportional to the electromagnetic interference intensity between two adjacent chips.

[0021] Preferably, the wire bonding wire is at least one of a straight line, an arc, and an inclined arc.

[0022] Preferably, when the wire bonding wire is an arc or an inclined arc, both ends of the wire bonding wire are fixed on the substrate by welding or arc wire bonding;

[0023] When the wire bonding wire is a straight line, the bottom of the wire bonding wire is fixed on the substrate by welding or arc wire bonding.

[0024] Preferably, after the electromagnetic shielding treatment is completed, cutting and singulation are performed to form a separate cavity-type electromagnetic shielding structure;

[0025] Perform qualification detection on the separate cavity-type electromagnetic shielding structure;

[0026] Package and ship the cavity-type electromagnetic shielding structures that pass the qualification detection, and sort the cavity-type electromagnetic shielding structures that fail the qualification detection to the recycling area.

[0027] According to a second aspect of an embodiment of the present invention, a cavity-divided electromagnetic shielding structure is provided, including:

[0028] A substrate, on which a plurality of chips are mounted;

[0029] A shielding part, disposed between adjacent chips where there is electromagnetic interference;

[0030] A thin film, covering above the shielding part, and the top of the shielding part is embedded in the thin film;

[0031] A plastic encapsulation layer, filled between the thin film and the substrate.

[0032] Preferably, the cavity-divided electromagnetic shielding structure further includes an electromagnetic shielding layer, which replaces the thin film and covers above the shielding part to contact the top of the shielding part.

[0033] Preferably, the shielding part at least includes wire bonding wires, metal blocks or metal posts.

[0034] According to a third aspect of an embodiment of the present invention, an electronic device is provided, which includes the above-mentioned cavity-divided electromagnetic shielding structure.

[0035] Compared with the prior art, the cavity-divided electromagnetic shielding structure and its manufacturing method provided by the embodiment of the present invention avoid the processes of grinding or laser ablation on the shielding part by covering a thin film above the shielding part, thereby simplifying the processing procedures and improving the processing efficiency. And, since the plastic encapsulation material is only encapsulated between the thin film and the substrate, the use of the plastic encapsulation material is reduced, and the overall production cost is lowered. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a flowchart of the manufacturing method of the cavity-divided electromagnetic shielding structure provided by the first embodiment of the present invention;

[0037] Figure 2A It is a schematic structural diagram of wire bonding wires disposed between two adjacent chips in the first embodiment of the present invention;

[0038] Figure 2B It is another schematic structural diagram of wire bonding wires disposed between two adjacent chips in the first embodiment of the present invention;

[0039] Figure 2C It is yet another schematic structural diagram of wire bonding wires disposed between two adjacent chips in the first embodiment of the present invention;

[0040] Figure 3 It is a schematic structural diagram of a thin film covering the top of the shielding part in the first embodiment of the present invention;

[0041] Figure 4 This is a schematic structural view of filling a molding compound between a thin film and a substrate and forming a molding layer in the first embodiment of the present invention;

[0042] Figure 5 This is a schematic structural view after removing the thin film in the first embodiment of the present invention;

[0043] Figure 6 This is a schematic structural view of forming a conformal electromagnetic shielding layer in the first embodiment of the present invention. Detailed implementation manners

[0044] The technical content of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] The embodiment of the present invention first provides a preparation method of a cavity-divided electromagnetic shielding structure. By using the Film Attach Molding process, a thin film material is pre-covered on the wire bonding lines, so that during the encapsulation process, the encapsulation material will not cover the top of the wire bonding lines, thereby avoiding the grinding or laser ablation process, reducing the product cost, and making the process simpler and more efficient. Below, it will be described in detail with reference to the accompanying drawings.

[0046] <First embodiment>

[0047] As Figure 1 shown, the preparation method of the cavity-divided electromagnetic shielding structure provided by the first embodiment of the present invention specifically includes steps S1 to S6:

[0048] S1: Mount chips on the substrate in sequence.

[0049] Specifically, in this embodiment, the substrate 1 can be a PCB substrate, and the PCB substrate is provided with ground posts for grounding. On the substrate 1, according to the processing requirements, each chip is respectively mounted at a preset position on the substrate 1 to implement different functions by using different chips.

[0050] It can be understood that since the substrate 1 is gradually approaching miniaturization, the distance between each chip is relatively close, which may cause electromagnetic interference between some adjacent chips.

[0051] S2: Set a shielding part 2 between adjacent chips or devices with electromagnetic interference.

[0052] Specifically, it includes steps S21 to S23:

[0053] S21: Determine two adjacent chips or devices with electromagnetic interference on the substrate 1.

[0054] Specifically, after the mounting of each chip on the substrate 1 is completed, according to the mounting positions of the chips and the functions of the chips, two adjacent chips with electromagnetic interference are identified.

[0055] S22: Set one or more wire bonding wires 21 between two adjacent chips, so that the one or more wire bonding wires 21 block between the two adjacent chips.

[0056] Specifically, as Figure 2A shown, after two adjacent chips or devices with electromagnetic interference are determined, set one or more wire bonding wires 21 between the two chips or devices, so as to form a wall-like structure with the one or more wire bonding wires 21 to block between the two adjacent chips or devices, so as to achieve the effect of electromagnetic shielding.

[0057] It can be understood that the number of wire bonding wires 21 is proportional to the electromagnetic interference intensity between two adjacent chips, that is: the stronger the electromagnetic interference intensity between two adjacent chips, the more the number of wire bonding wires 21 is set, and vice versa. And, the distance between two adjacent wire bonding wires 21 is inversely proportional to the electromagnetic interference intensity between two adjacent chips, that is: the stronger the electromagnetic interference intensity between two adjacent chips, the denser the wire bonding wires 21 are set, and vice versa. Thus, the appropriate number of wire bonding wires can be selected according to the electromagnetic interference situation between different chips for setting.

[0058] In this embodiment, the wire bonding wire 21 is an arc, so when setting the wire bonding wire 21, both ends of the wire bonding wire 21 should be fixed on the substrate 1 by welding or arc wire bonding. Similarly, as Figure 2B shown, in an embodiment of the present invention, the wire bonding wire 21 can also be an inclined arc. It can be understood that setting the wire bonding wire 21 in the structural form of an arc or an inclined arc can provide a certain elastic adjustment space when pressing the thin film 3, so as to facilitate the covering of the thin film 3. In another embodiment, as Figure 2C shown, the wire bonding wire 21 can also be a straight line. When the wire bonding wire 21 is a straight line, the bottom of the wire bonding wire 21 is fixed on the substrate 1 by welding or arc wire bonding.

[0059] S23: Repeat the above steps S21 - S22 until wire bonding wires 21 are set between all adjacent chips with electromagnetic interference on the substrate 1.

[0060] It can be understood that in this embodiment, the shielding part 2 is the shielding structure integrally formed by multiple wire bonding wires 21. In other embodiments, the wire bonding wire 21 can also be replaced with structures such as metal blocks or metal columns, which are not specifically limited herein.

[0061] S3: Pre-cover the injection mold with a film, and cover the injection mold on the substrate 1 so that the top of the shielding portion 2 is embedded in the film.

[0062] Specifically, in this embodiment, an injection mold (not shown in the figure) needs to be pre-set before injection molding. The injection mold has vacuum suction holes. Before setting the injection mold, the film 3 is pre-vacuum-sucked on the end face of the injection mold. Then, the injection mold is covered on the substrate 1 and the shielding portion 2 is wrapped inside. Gently press the film 3 so that the top of the shielding portion 2 is embedded in the film 3. Among them, the material of the film 3 can be adaptively selected according to needs. By covering the film 3 on the top of the shielding portion 2, the injection mold, the film 3 and the substrate 1 jointly enclose a filling space for filling with encapsulation material.

[0063] S4: Inject encapsulation material into the injection mold to form an encapsulation layer.

[0064] Specifically, as Figure 4 shown, when the filling space is formed through step S3, the encapsulation material (for example: epoxy molding compound) is filled into the filling space to form the encapsulation layer 4.

[0065] It can be understood that since only a small part of the top of the shielding portion 2 is embedded in the film 3 in step S3, when the encapsulation is completed with the encapsulation material, the height of the encapsulation layer 4 in the Z-axis direction will be slightly lower than the height of the shielding portion 2.

[0066] S5: Remove the injection mold to correspondingly remove the film 3 so that the top of the shielding portion 2 protrudes from the encapsulation layer 4.

[0067] Specifically, as Figure 5 shown, when the encapsulation is completed, a demolding process is required. During the demolding process, the injection mold is removed together with the film 3, thereby removing the film 3 so that the top of the shielding portion 2 will protrude from the encapsulation layer 4, thus eliminating the process of exposing the shielding portion 2 by grinding or laser ablation, simplifying the production process and improving the production efficiency.

[0068] In addition, since there is no excess encapsulation material in this method, waste of encapsulation material can be avoided and the production cost is reduced.

[0069] S6: Cut and split to form individual cavity-type electromagnetic shielding structures.

[0070] S7: Fabricate the electromagnetic shielding layer 5.

[0071] Specifically, as Figure 6As shown, after removing the film 3 to expose the top of the shielding part 2, a metal material is covered on the top of the shielding part 2, so that the metal material is in contact with the top of the shielding part 2, and a metal coating is made on the surface of the separate cavity type electromagnetic shielding structure, thereby forming an electromagnetic shielding layer 5. Among them, the electromagnetic shielding layer 5 is connected to the grounding post in the substrate 1 through the shielding part 2 to achieve the electromagnetic shielding effect.

[0072] S8: Conduct a qualification test on the separate cavity type electromagnetic shielding structure.

[0073] S9: Package and ship the cavity type electromagnetic shielding structure that has passed the qualification test, and sort the cavity type electromagnetic shielding structure that has not passed the qualification test to the recycling area.

[0074] <Second Embodiment>

[0075] Based on the preparation method provided in the first embodiment, the second embodiment of the present invention provides a cavity type electromagnetic shielding structure. As Figure 4 shown, the cavity type electromagnetic shielding structure includes a substrate 1, a shielding part 2, a film 3 and a plastic package layer 4.

[0076] Among them, a plurality of chips are mounted on the substrate 1; the shielding part 2 is arranged between adjacent chips where there is electromagnetic interference; the film 3 covers above the shielding part 2, and the top of the shielding part 2 is embedded in the film 3; the plastic package layer 4 is filled between the film 3 and the substrate 1.

[0077] In addition, as Figure 6 shown, in an embodiment of the present invention, the cavity type electromagnetic shielding structure further includes an electromagnetic shielding layer 5. The electromagnetic shielding layer 5 is used to replace the film 3 and covers above the shielding part 2 to be in contact with the top of the shielding part 2. Among them, the process of using the electromagnetic shielding layer 5 to replace the film 3 is the above steps S5 - S6, which will not be elaborated here.

[0078] To sum up, the cavity type electromagnetic shielding structure and its preparation method provided by the embodiments of the present invention cover the film 3 above the shielding part 2, avoiding the processes of grinding or laser ablation on the shielding part 2, thus simplifying the processing procedures and improving the processing efficiency. And since the plastic packaging material is only plastic - packaged between the film 3 and the substrate 1, the use of the plastic packaging material is reduced, and the overall production cost is lowered.

[0079] <Third Embodiment>

[0080] Based on the second embodiment, the third embodiment of the present invention further provides an electronic device, which includes the above - mentioned cavity type electromagnetic shielding structure, and can be a smart phone, a tablet computer, various wearable devices, etc.

[0081] The above has described in detail the cavity-divided electromagnetic shielding structure, preparation method and electronic device provided by the present invention. For those of ordinary skill in the art, any obvious changes made to it without departing from the essence of the present invention will constitute an infringement of the patent right of the present invention and will bear corresponding legal responsibilities.

Claims

1. A preparation method of a cavity-divided electromagnetic shielding structure, characterized in that it includes the following steps: Mount chips on the substrate in sequence; Set shielding parts between adjacent chips with electromagnetic interference; Cover a film on the injection mold in advance, and cover the injection mold on the substrate so that the top of the shielding part is embedded in the film; only a part of the top of the shielding part is embedded inside the film; Inject encapsulation material into the injection mold to form an encapsulation layer; Remove the injection mold to correspondingly remove the film, so that the top of the shielding part protrudes from the encapsulation layer; Cover a metal material on the top of the shielding part and make the metal material contact with the top of the shielding part to form a conformal electromagnetic shielding layer.

2. The preparation method according to claim 1, characterized in that The step of setting shielding parts between adjacent chips with electromagnetic interference specifically includes: Determine two adjacent chips or devices with electromagnetic interference on the substrate; Set one or more wire bonding wires between the two adjacent chips, so that one or more wire bonding wires block between the two adjacent chips or devices; Repeat the above operation until wire bonding wires are set between all adjacent chips or devices with electromagnetic interference on the substrate.

3. The preparation method according to claim 2, characterized in that: The number of the wire bonding wires is proportional to the electromagnetic interference intensity between two adjacent chips, and the distance between two adjacent wire bonding wires is inversely proportional to the electromagnetic interference intensity between two adjacent chips.

4. The preparation method according to claim 2, characterized in that: The wire bonding wire is at least one of a straight line or an arc.

5. The preparation method according to claim 4, characterized in that: When the wire bonding wire is an arc, both ends of the wire bonding wire are fixed on the substrate by welding or arc wire bonding; When the wire bonding wire is a straight line, the bottom of the wire bonding wire is fixed on the substrate by welding or arc wire bonding.

6. The preparation method according to claim 1, characterized in that it further includes the following steps: After completing the electromagnetic shielding treatment, perform cutting and dicing to form a separate cavity-divided electromagnetic shielding structure; Perform qualification detection on the separate cavity-divided electromagnetic shielding structure; Package and ship the cavity-divided electromagnetic shielding structures that pass the qualification detection, and sort the cavity-divided electromagnetic shielding structures that fail the qualification detection to the recycling area.

7. A cavity-divided electromagnetic shielding structure, characterized in that it is prepared by using the preparation method of the cavity-divided electromagnetic shielding structure according to any one of claims 1 to 6.

8. The cavity-divided electromagnetic shielding structure according to claim 7, characterized in that: The shielding part includes at least one of a wire bonding wire or a metal block.

9. An electronic device, characterized in that it includes the cavity-divided electromagnetic shielding structure according to any one of claims 7 to 8.

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