A method for manufacturing a high-density electromagnetic shield

Abstract

This invention discloses a method for manufacturing a high-density electromagnetic shield, relating to the field of integrated circuit packaging technology. The method includes the following steps: manufacturing multiple insulating blocks on a substrate, with a clearance groove at the center of each insulating block, allowing an integrated circuit chip to be positioned at the bottom of the corresponding clearance groove; installing a mesh cover, with multiple flexible portions at the lower end of the mesh cover, the flexible portions being embedded in the corresponding clearance grooves; bombarding the substrate and mesh cover with plasma; depositing a metal shielding layer on the substrate and mesh cover; and removing the mesh cover. This invention can improve the yield and lifespan of integrated circuit chip packaging.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit packaging technology, and in particular to a method for manufacturing a high-density electromagnetic shield. Background Technology

[0002] In the semiconductor technology field, many integrated circuit chips are highly sensitive to electromagnetic interference, such as radio frequency (RF) chips, especially high-frequency RF chips. These chips must be electromagnetically shielded before operation. Current electromagnetic shielding techniques often involve placing a metal casing around the chip's package or forming a metal film on the chip's package using magnetron sputtering. However, installing a metal casing increases the volume of the chip package structure, making it unsuitable for high-density board-level packaging. Using magnetron sputtering to form a metal layer on the chip package is prone to oversputtering during the sputtering process, causing short circuits, and the adhesion between the metal layer and the package is poor, leading to detachment during use. This results in low package yield. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for manufacturing a high-density electromagnetic shielding cover, which can improve the yield of integrated circuit chip packaging.

[0004] A method for manufacturing a high-density electromagnetic shield according to a first aspect of the present invention includes the following steps: manufacturing a plurality of insulating blocks on a substrate, wherein a clearance groove is provided at the center of each insulating block, and an integrated circuit chip is disposed at the bottom of the corresponding clearance groove; installing a mesh cover, wherein a plurality of flexible portions are provided at the lower end of the mesh cover, and the flexible portions are embedded in the corresponding clearance grooves; bombarding the substrate and the mesh cover with plasma; depositing a metal shielding layer on the substrate and the mesh cover; and removing the mesh cover.

[0005] According to an embodiment of the present invention, a method for manufacturing a high-density electromagnetic shield has at least the following beneficial effects: when plating the metal shielding layer, the metal shielding layer is covered by a mesh cover to form a specified shape on the insulating block, preventing short circuits caused by the metal shielding layer plating on the integrated circuit chip, thereby improving the yield of integrated circuit chip packaging. Before plating the metal shielding layer, the insulating block is cleaned with plasma to keep the surface of the insulating block clean and to enhance the bonding force between the surface of the insulating block and the metal shielding layer, making the metal shielding layer less prone to falling off and extending the service life of integrated circuit chip packaging.

[0006] According to some embodiments of the present invention, the manufacturing of multiple insulating blocks on a substrate includes the following steps: fixing a mold on the substrate, adding insulating material into the mold, waiting for the insulating material to cure, and then removing the mold.

[0007] According to some embodiments of the present invention, the fabrication of a plurality of insulating blocks on a substrate includes the following steps: applying an insulating material to the substrate followed by laser etching.

[0008] According to some embodiments of the present invention, the fabrication of a plurality of insulating blocks on a substrate includes the following steps: dry etching after coating the substrate with an insulating material.

[0009] According to some embodiments of the present invention, the mesh cover includes a plurality of structural parts and a plurality of connecting parts, the structural parts being provided corresponding to each insulating block, the flexible part being connected to the lower end of the corresponding structural part, and adjacent structural parts being connected by the connecting parts.

[0010] According to some embodiments of the present invention, the lower end of the structure is larger than the upper end of the clearance groove.

[0011] According to some embodiments of the present invention, the deposition of a metal shielding layer on the substrate and the mesh cover includes the following steps: physical vapor deposition.

[0012] According to some embodiments of the present invention, the deposition of a metal shielding layer on the substrate and the mesh cover includes the following steps: physical vapor deposition and chemical deposition.

[0013] According to some embodiments of the present invention, the deposition of a metal shielding layer on the substrate and the mesh cover includes the following steps: physical vapor deposition and electroplating.

[0014] According to some embodiments of the present invention, the thickness of the metal shielding layer is greater than Δ, and the formula for calculating Δ is as follows: Where Δ is the minimum thickness of the metal shielding layer, ω is the angular frequency at which the integrated circuit chip operates or the angular frequency of external electromagnetic waves when the integrated circuit chip is operating, μ is the permeability of the metal shielding layer, and γ is the conductivity of the metal shielding layer.

[0015] A method for manufacturing a high-density electromagnetic shield according to an embodiment of the present invention has at least the following beneficial effects:

[0016] (1) When plating the metal shielding layer, the integrated circuit chip is covered by a mesh cover so that the metal shielding layer forms a specified shape on the insulating block, preventing short circuits caused by the metal shielding layer plating on the integrated circuit chip, and improving the yield of integrated circuit chip packaging.

[0017] (2) Before plating the metal shielding layer, the insulating block is cleaned with plasma to keep the surface of the insulating block clean and to enhance the bonding force between the surface of the insulating block and the metal shielding layer, making the metal shielding layer less likely to fall off and extending the service life of the integrated circuit chip package.

[0018] (3) By calculating the minimum thickness required for the metal shielding layer, and on the premise of ensuring the product qualification rate, the corresponding molding process of the metal shielding layer can be selected, which is conducive to improving production efficiency and reducing production costs.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0021] Figure 1 This is a schematic diagram of a substrate and an insulating block according to an embodiment of the present invention;

[0022] Figure 2 This is an exploded view of a substrate and a mesh cover according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of a substrate and mesh assembly according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of a metal shielding layer according to an embodiment of the present invention;

[0025] Figure 5 This is a top view of a substrate after a mesh cover has been installed in an embodiment of the present invention.

[0026] Icon labels:

[0027] substrate 100;

[0028] Insulating block 200, clearance groove 210;

[0029] Integrated circuit chip 300;

[0030] Net cover 400, flexible part 401, structural part 410, connecting part 420;

[0031] Metal shielding layer 500. Detailed Implementation

[0032] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0034] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0035] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0036] Reference Figures 1 to 5As shown, one embodiment of the present invention discloses a method for manufacturing a high-density electromagnetic shield, comprising: manufacturing a plurality of insulating blocks 200 on a substrate 100, wherein the insulating blocks 200 are made of polymer insulating materials such as epoxy resin and polyurethane. The height of the insulating blocks 200 is determined by the size of the integrated circuit chip 300, and is generally 7mm. A relief groove 210 is provided in the center of the insulating block 200, and the integrated circuit chip 300 is placed in the relief groove 210, so that the integrated circuit chip 300 is positioned at the bottom of the corresponding relief groove 210; the shape and size of the relief groove 210 match the shape and size of the integrated circuit chip 300, so that the integrated circuit chip 300 is just embedded in the relief groove 210. It is foreseeable that in some other embodiments, in order to facilitate the connection of the lower end of the integrated circuit chip 300 to the circuit, the integrated circuit chip 300 is connected to the substrate 100, and the pins of the integrated circuit chip 300 are provided below the substrate 100. When manufacturing the insulating block 200, the integrated circuit chip 300 is already located on the substrate 100, so there is no need to perform the step of placing the integrated circuit chip 300 in the relief groove 210. Since the integrated circuit chip 300 is typically square, the insulating block 200 is also square to match the shape of the integrated circuit chip 300. A mesh cover 400 is installed, and multiple flexible parts 401 are provided at the lower end of the mesh cover 400. The flexible parts 401 are made of materials with low hardness, such as plastic, rubber, or silicone. Because the flexible parts 401 are very close to the integrated circuit chip 300 after the mesh cover 400 is installed, there is even a possibility that the flexible parts 401 may come into contact with the integrated circuit chip 300. Therefore, to prevent damage to the integrated circuit chip 300, the flexible parts 401 need to be made of materials with low hardness. The flexible part 401 is embedded in the corresponding clearance groove 210; the assembly of the substrate 100 and the mesh cover 400 is placed in a plasma cleaning equipment, and plasma is used to bombard the substrate 100 and the mesh cover 400 to remove residual organic matter, oxides and other impurities from the outer surface of the insulating block 200; a metal shielding layer 500 is deposited on the substrate 100 and the mesh cover 400; after the outer surface of the insulating block 200 on the substrate 100 is coated with the metal shielding layer 500, the mesh cover 400 is removed. Plasma cleaning of the outer surface of the insulating block 200 before plating the metal shielding layer 500 helps to improve the bonding force between the metal shielding layer 500 and the outer surface of the insulating block 200, making the metal shielding layer 500 less likely to fall off. Since the height of the insulating block 200 can be set very small, the thickness of the metal shielding layer 500 is also small compared to existing metal shell packages, thus reducing the package volume. The metal shielding layer 500 can be deposited on the insulating blocks 200 on the same substrate 100 simultaneously, improving production efficiency and reducing production costs.

[0037] Reference Figures 1 to 5As shown, manufacturing multiple insulating blocks 200 on substrate 100 involves the following steps: creating a mold corresponding to the size and quantity of integrated circuit chips 300; fixing the mold to substrate 100 using bolts or glue; adding insulating material to the mold; and waiting for the insulating material to cure, which will form multiple insulating blocks 200 on substrate 100. Then, the mold is removed, leaving the insulating blocks 200 on substrate 100. The advantages of using molds to manufacture insulating blocks 200 are low cost, simple process, and high production efficiency. The disadvantages are that air bubbles are easily present in the mold or the mold precision is low, resulting in lower dimensional accuracy and surface quality of the insulating blocks 200, making it only suitable for integrated circuit chips 300 with low packaging precision requirements.

[0038] Reference Figures 1 to 5 As shown, it can be understood that manufacturing multiple insulating blocks 200 on substrate 100 includes the following steps: coating a layer of insulating material of uniform thickness on substrate 100, waiting for the insulating material to cure, and then placing it in a laser etching machine for laser etching, using the laser etching machine to carve the shape of the insulating block 200 from the cured insulating material. The advantage of using laser etching to carve the insulating block 200 is that the dimensional accuracy and surface quality of the formed insulating block 200 are better than those using mold forming. However, the disadvantage is that the process time and manufacturing cost are higher than those using mold forming. Therefore, the method of laser etching to carve the insulating block 200 is suitable for integrated circuit chips 300 with high packaging precision requirements.

[0039] Reference Figures 1 to 5 As shown, it can be understood that fabricating multiple insulating blocks 200 on substrate 100 includes the following steps: coating a layer of insulating material of uniform thickness on substrate 100, waiting for the insulating material to cure, coating a layer of photoresist of uniform thickness on the insulating material, exposing and developing the photoresist, forming cured photoresist on the insulating material where the insulating blocks 200 need to be formed, and then placing substrate 100 in a plasma etching machine to perform dry etching on the insulating material on substrate 100. After etching, the photoresist is removed by cleaning with organic solvents such as acetone. The advantage is that the dimensional accuracy and surface quality of the manufactured insulating blocks 200 are better than those of laser-etched insulating blocks 200, but the disadvantage is that the process time and manufacturing cost are higher than those of laser-etched insulating blocks 200. Therefore, the dry etching method is suitable for integrated circuit chips 300 with extremely high packaging precision requirements.

[0040] Reference Figure 2 and Figure 3As shown, the mesh cover 400 includes multiple structural portions 410 and multiple connecting portions 420, which are integrally formed. Each structural portion 410 is provided corresponding to each insulating block 200, with the position of each structural portion 410 corresponding one-to-one with the position of each insulating block 200. A flexible portion 401 is connected to the lower end of the corresponding structural portion 410, allowing the flexible portion 401 below each structural portion 410 to be embedded in the corresponding clearance groove 210. It is foreseeable that when processing integrated circuit chips 300 of different sizes, mesh covers 400 of different sizes will be required, with adjacent structural portions 410 connected by connecting portions 420. The connecting portions 420 serve to fix adjacent structural portions 410. Since the substrate 100 is typically circular, the overall shape of the mesh cover 400 is also circular.

[0041] Reference Figures 1 to 5 As shown, it can be understood that the lower dimension of the structural portion 410 is larger than the upper dimension of the relief groove 210. The lower dimension of the structural portion 410 is smaller than the upper dimension of the insulating block 200. To prevent the metal shielding layer 500 from entering the relief groove 210, if the lower dimension of the structural portion 410 is equal to or smaller than the upper dimension of the relief groove 210, the metal shielding layer 500 could easily enter the relief groove 210 through gaps during plating, causing damage to the integrated circuit chip 300. Therefore, the lower dimension of the structural portion 410 being larger than the upper dimension of the relief groove 210 allows the lower dimension of the structural portion 410 to abut against the upper dimension of the insulating block 200, effectively improving the yield rate of the integrated circuit chip 300 package.

[0042] Reference Figures 1 to 5 As shown, it can be understood that depositing the metal shielding layer 500 on the substrate 100 and the mesh cover 400 includes the following steps: Under vacuum conditions, the substrate 100 and the mesh cover 400 are deposited together using physical vapor deposition (PVD). Ion beam assisted deposition is used to deposit evaporated titanium or copper metal gas onto the outer surface of the insulating block 200 to form the metal shielding layer 500. By controlling parameters such as the heating temperature and deposition rate of the titanium or copper metal, the thickness and uniformity of the metal shielding layer 500 are controlled. The advantage of physical vapor deposition is that it can precisely control the thickness and uniformity of the metal shielding layer 500, and the adhesion between the metal shielding layer 500 and the outer surface of the insulating block 200 is strong and not easily detached. However, the disadvantage is that the maximum thickness of the physical vapor deposition film is only 10 micrometers, therefore it is only suitable for integrated circuit chip 300 packages with a relatively thin metal shielding layer 500.

[0043] Reference Figures 1 to 5As shown, it can be understood that depositing the metal shielding layer 500 on the substrate 100 and the mesh cover 400 includes the following steps: physical vapor deposition (PVD) and chemical deposition. Since the maximum thickness of PVD deposition is only 10 micrometers, it is only suitable for integrated circuit chip 300 packages with a relatively thin metal shielding layer 500. When it is necessary to increase the thickness of the metal shielding layer 500, chemical deposition is performed after PVD deposition. The metal shielding layer 500 manufactured by PVD deposition and chemical deposition is generally made of the same material to increase the bonding force between the two metal shielding layers 500 produced by different processes and prevent the coating from peeling off.

[0044] Reference Figures 1 to 5 As shown, it can be understood that depositing the metal shielding layer 500 on the substrate 100 and the mesh cover 400 includes the following steps: physical vapor deposition (PVD) and electroplating. Since the maximum thickness of PVD is only 10 micrometers, it is only suitable for integrated circuit chip 300 packages with a relatively thin metal shielding layer 500. When it is necessary to increase the thickness of the metal shielding layer 500, electroplating is performed after PVD deposition. The metal shielding layer 500 manufactured by PVD and electroplating is generally made of the same material to increase the bonding force between the two different processes and prevent the coating from peeling off. It is foreseeable that whether electroplating or chemical plating is used depends on the material of the substrate 100. When the material of the substrate 100 is suitable for electroplating, electroplating is used; when the material of the substrate 100 is suitable for chemical plating, chemical plating is used.

[0045] Reference Figures 1 to 5 As shown, it can be understood that the thickness of the metal shielding layer 500 is greater than Δ, and the formula for calculating Δ is... Where Δ represents the minimum thickness of the metal shielding layer 500, ω represents the angular frequency of the integrated circuit chip 300 (calculated as ω = 2πf), f represents the operating frequency of the integrated circuit chip 300 (obtainable from the design parameters), μ represents the permeability of the metal shielding layer 500 material (an inherent property of the selected material), and γ represents the conductivity of the metal shielding layer 500 material (an inherent property of the selected material). It is foreseeable that if the integrated circuit chip 300 is sensitive to external electromagnetic interference, then f represents the frequency of the external electromagnetic waves during its operation to ensure that the integrated circuit chip 300 is not affected by external electromagnetic interference. If other components near the integrated circuit chip 300 are sensitive to electromagnetic interference, then f represents the frequency of the integrated circuit chip 300 itself during operation to ensure that the electromagnetic waves emitted by the integrated circuit chip 300 do not affect other components. By calculating the minimum required thickness of the metal shielding layer 500 and selecting the corresponding molding process for the metal shielding layer 500, it is beneficial to shorten the process time and reduce production costs while ensuring product qualification rate.

[0046] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for manufacturing a high-density electromagnetic shielding cover, characterized in that, Includes the following steps: Multiple insulating blocks (200) are manufactured on a substrate (100), and a relief groove (210) is provided in the center of the insulating block (200) so that the integrated circuit chip (300) is disposed at the bottom of the corresponding relief groove (210); A mesh cover (400) is installed, and a plurality of flexible parts (401) are provided at the lower end of the mesh cover (400), and the flexible parts (401) are embedded in the corresponding relief grooves (210); The substrate (100) and the mesh cover (400) are bombarded with plasma; A metal shielding layer (500) is deposited on the substrate (100) and the mesh cover (400); Remove the mesh cover (400).

2. The method for manufacturing a high-density electromagnetic shielding cover according to claim 1, characterized in that: The process of manufacturing multiple insulating blocks (200) on a substrate (100) includes the following steps: fixing a mold on the substrate (100), adding insulating material into the mold, waiting for the insulating material to cure, and then removing the mold.

3. The method for manufacturing a high-density electromagnetic shielding cover according to claim 1, characterized in that: The process of fabricating a plurality of insulating blocks (200) on a substrate (100) includes the following steps: applying an insulating material to the substrate (100) and then laser etching.

4. The method for manufacturing a high-density electromagnetic shielding cover according to claim 1, characterized in that: The process of fabricating a plurality of insulating blocks (200) on a substrate (100) includes the following steps: dry etching after coating an insulating material onto the substrate (100).

5. The method for manufacturing a high-density electromagnetic shielding cover according to claim 1, characterized in that: The mesh cover (400) includes a plurality of structural parts (410) and a plurality of connecting parts (420). The structural parts (410) are provided corresponding to each insulating block (200). The flexible part (401) is connected to the lower end of the corresponding structural part (410). Adjacent structural parts (410) are connected to each other through the connecting parts (420).

6. The method for manufacturing a high-density electromagnetic shielding cover according to claim 5, characterized in that: The lower end of the structure (410) is larger than the upper end of the clearance groove (210).

7. The method for manufacturing a high-density electromagnetic shielding cover according to claim 1, characterized in that: The process of depositing a metal shielding layer (500) on the substrate (100) and the mesh cover (400) includes the following steps: physical vapor deposition coating.

8. The method for manufacturing a high-density electromagnetic shielding cover according to claim 7, characterized in that: The process of depositing a metal shielding layer (500) on the substrate (100) and the mesh cover (400) includes the following steps: physical vapor deposition and chemical deposition.

9. The method for manufacturing a high-density electromagnetic shielding cover according to claim 8, characterized in that: The process of depositing a metal shielding layer (500) on the substrate (100) and the mesh cover (400) includes the following steps: physical vapor deposition and electroplating.

10. The method for manufacturing a high-density electromagnetic shielding cover according to claim 1, characterized in that: The thickness of the metal shielding layer (500) is greater than Δ, and the formula for calculating Δ is: Where Δ is the minimum thickness of the metal shielding layer (500), ω is the angular frequency of the integrated circuit chip (300) or the angular frequency of the external electromagnetic wave when the integrated circuit chip (300) is working, μ is the permeability of the metal shielding layer (500), and γ is the conductivity of the metal shielding layer (500).

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