A method for manufacturing a fine electromagnetic shield

Abstract

This invention discloses a method for manufacturing a refined electromagnetic shielding cover, 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, so that an integrated circuit chip is positioned at the bottom of the corresponding clearance groove; coating the insulating blocks with photoresist, exposing and developing the photoresist to form a protective portion, the lower end of which is embedded in the corresponding clearance groove; bombarding the substrate and the protective portion with plasma; depositing a metal shielding layer on the substrate, insulating blocks, and protective portion; and removing the protective portion. This invention can improve the yield rate 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 refined electromagnetic shielding cover. 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 refined electromagnetic shielding cover manufacturing method, which can improve the yield of integrated circuit chip packaging.

[0004] A method for manufacturing a refined 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; coating the insulating blocks with photoresist, exposing and developing the photoresist to form a protective portion, wherein the lower end of the protective portion is embedded in the corresponding clearance groove; bombarding the substrate and the protective portion with plasma; depositing a metal shielding layer on the substrate, the insulating blocks and the protective portion; and removing the protective portion.

[0005] According to an embodiment of the present invention, a method for manufacturing a refined electromagnetic shield has at least the following beneficial effects: when depositing the metal shielding layer, the integrated circuit chip is covered by a protective portion formed by photoresist, so that the metal shielding layer forms a specified shape on the insulating block, preventing short circuits caused by the metal shielding layer deposited on the integrated circuit chip, thereby improving the yield of integrated circuit chip packaging. Before depositing 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 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 protective part includes a vertical part and a horizontal part, the vertical part is connected to the lower end of the horizontal part, the lower end of the vertical part is embedded in the relief groove, the horizontal part abuts against the upper end of the insulating block, and the size of the lower end of the horizontal part is larger than the size of the upper end of the relief groove.

[0010] According to some embodiments of the present invention, removing the protective part includes the following steps: immersing the substrate and the insulating block in a solvent, waiting for the protective part to dissolve, and then removing the substrate and the insulating block.

[0011] According to some embodiments of the present invention, the deposition of a metal shielding layer on the substrate and the protective portion 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 protective portion 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 protective portion 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 of the integrated circuit chip during operation or the angular frequency of the external electromagnetic wave when the integrated circuit chip is working, 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 refined electromagnetic shield according to an embodiment of the present invention has at least the following beneficial effects: (1) When plating the metal shielding layer, the integrated circuit chip is covered by the protective part formed by photoresist, so that the metal shielding layer forms a specified shape on the insulating block, preventing short circuit caused by the metal shielding layer on the integrated circuit chip, and improving the yield of integrated circuit chip packaging. (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. (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 is selected, which is conducive to improving production efficiency and reducing production costs.

[0016] 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

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of a substrate and an insulating block according to one embodiment of the present invention; Figure 2 This is a schematic diagram of the protective part according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a metal shielding layer according to an embodiment of the present invention.

[0018] Icon labels: substrate 100; Insulating block 200, clearance groove 210; Integrated circuit chip 300; Protective section 400, vertical section 410, horizontal section 420; Metal shielding layer 500. Detailed Implementation

[0019] 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.

[0020] 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.

[0021] 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.

[0022] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" 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.

[0023] Reference Figures 1 to 3As shown, one embodiment of the present invention discloses a method for manufacturing a refined 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 layer of photoresist is uniformly coated on the insulating block 200, and the photoresist is exposed and developed to form the protective part 400. The process of exposing and developing the photoresist is existing technology and will not be described in detail. The advantage of using photoresist to form the protective part 400 is its high precision, which allows for the obtaining of a metal shielding layer 500 with an accurate shape. The lower end of the protective part 400 is embedded in a corresponding relief groove 210; the lower end of the protective part 400 protects the integrated circuit chip 300. The assembly of the substrate 100 and the protective part 400 is placed in a plasma cleaning device, and plasma is used to bombard the substrate 100 and the protective part 400 to clean the residual organic matter, oxides, and other impurities on the outer surface of the insulating block 200. A metal shielding layer 500 is deposited on the substrate 100 and the protective part 400. After the outer surface of the insulating block 200 on the substrate 100 is coated with the metal shielding layer 500, the protective part 400 is removed. Plasma cleaning of the outer surface of the insulating block 200 before plating the metal shielding layer 500 helps 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 prone to detachment. Since the height of the insulating block 200 can be set very small, and the thickness of the metal shielding layer 500 is also small compared to existing metal casing packages, the package volume can be reduced. The metal shielding layer 500 can be plated simultaneously on the insulating blocks 200 on the same substrate 100, enabling mass production to improve production efficiency and reduce production costs.

[0024] Reference Figures 1 to 3As 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.

[0025] Reference Figures 1 to 3 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.

[0026] Reference Figures 1 to 3 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.

[0027] Reference Figures 1 to 3As shown, the protective portion 400 includes a vertical portion 410 and a horizontal portion 420. The vertical portion 410 is connected to the lower end of the horizontal portion 420, and the vertical portion 410 and the horizontal portion 420 are integrally formed. The shape and size of the lower end of the vertical portion 410 match the shape and size of the relief groove 210. The vertical portion 410 is formed by curing photoresist located in the relief groove 210 during exposure. The lower end of the vertical portion 410 is embedded in the relief groove 210. The horizontal portion 420 abuts against the upper end of the insulating block 200. The horizontal portion 420 is formed by curing photoresist located above the insulating block 200 during exposure. The size of the lower end of the horizontal portion 420 is larger than the size of the upper end of the relief groove 210. The size of the lower end of the horizontal portion 420 is smaller than the size of the upper end of the insulating block 200. To prevent the metal shielding layer 500 from entering the relief groove 210, if the size of the lower end of the vertical part 410 is equal to or smaller than the size of the upper end of the relief groove 210, the metal shielding layer 500 can easily enter the relief groove 210 through the gap during the plating process, causing damage to the integrated circuit chip 300. Therefore, the size of the lower end of the vertical part 410 is larger than the size of the upper end of the relief groove 210, which allows the lower end of the structure to abut against the upper end of the insulating block 200, effectively improving the yield of the integrated circuit chip 300 package.

[0028] Reference Figures 1 to 3 As shown, it can be understood that removing the protective part 400 includes the following steps: immersing the substrate 100 and the insulating block 200 in a solvent and oscillating them at a certain amplitude, waiting for the protective part 400 to dissolve in the solvent, and then removing the substrate 100 and the insulating block 200. It is foreseeable that if the material of the substrate 100 reacts with the solvent or can dissolve in the solvent, plasma can be generated by ionizing gas under high-frequency action, and the plasma can be used to bombard or corrode the protective part 400 to achieve the purpose of removing the protective part 400.

[0029] Reference Figures 1 to 3 As shown, it can be understood that depositing a metal shielding layer 500 on the substrate 100 and the protective part 400 includes the following steps: Under vacuum conditions, the substrate 100 and the protective part 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. The thickness and uniformity of the metal shielding layer 500 are controlled by adjusting parameters such as the heating temperature and deposition rate of the titanium or copper metal. The advantage of PVD deposition is that it allows for precise control of 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 PVD deposition is only 10 micrometers, therefore it is only suitable for integrated circuit chip 300 packages with relatively thin metal shielding layers 500.

[0030] Reference Figures 1 to 3As shown, it can be understood that depositing the metal shielding layer 500 on the substrate 100 and the protective part 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.

[0031] Reference Figures 1 to 3 As shown, it can be understood that depositing the metal shielding layer 500 on the substrate 100 and the protective part 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.

[0032] Reference Figures 1 to 3 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 is the minimum thickness of the metal shielding layer 500, ω is the angular frequency of the integrated circuit chip 300 (ω = 2πf), f is the operating frequency of the integrated circuit chip 300 (the value of f can be obtained by looking up the design parameters of the integrated circuit chip 300), μ is the permeability of the metal shielding layer 500 material (μ is an inherent property parameter of the selected material), and γ is the conductivity of the metal shielding layer 500 material (γ is an inherent property parameter of the selected material). It is foreseeable that if the integrated circuit chip 300 is sensitive to external electromagnetic interference, then f is the frequency of the external electromagnetic waves when the integrated circuit chip 300 is operating, to ensure that the integrated circuit chip 300 is not affected by external electromagnetic interference. When other components near the integrated circuit chip 300 are sensitive to electromagnetic interference, then f is the frequency of the integrated circuit chip 300 itself when operating, to ensure that the electromagnetic waves emitted by the integrated circuit chip 300 itself 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.

[0033] 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 refined 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); Photoresist is coated on the insulating block (200), and the photoresist is exposed and developed to form a protective part (400), the lower end of the protective part (400) being embedded in the corresponding relief groove (210); The substrate (100) and the protective part (400) are bombarded with plasma. A metal shielding layer (500) is plated on the substrate (100), the insulating block (200) and the protective part (400). Remove the protective part (400).

2. The method for manufacturing a refined 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 refined 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 refined 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 refined electromagnetic shielding cover according to claim 1, characterized in that: The protective part (400) includes a vertical part (410) and a horizontal part (420). The vertical part (410) is connected to the lower end of the horizontal part (420). The lower end of the vertical part (410) is embedded in the relief groove (210). The horizontal part (420) abuts against the upper end of the insulating block (200). The size of the lower end of the horizontal part (420) is larger than the size of the upper end of the relief groove (210).

6. The method for manufacturing a refined electromagnetic shielding cover according to claim 1, characterized in that: The removal of the protective part (400) includes the following steps: immersing the substrate (100) and the insulating block (200) in a solvent, waiting for the protective part (400) to dissolve, and then taking out the substrate (100) and the insulating block (200).

7. The method for manufacturing a refined 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 protective portion (400) includes the following steps: physical vapor deposition coating.

8. The method for manufacturing a refined 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 protective portion (400) includes the following steps: physical vapor deposition and chemical deposition.

9. The method for manufacturing a refined 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 protective part (400) includes the following steps: physical vapor deposition and electroplating.

10. The method for manufacturing a refined 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).

Images