An encapsulation structure with electromagnetic shielding function and its encapsulation method

Abstract

The present invention discloses a packaging structure with electromagnetic shielding function and its manufacturing method, which includes a flexible substrate layer (10), a chip (30), a metal enclosure (50), a molding compound coating layer (60) and an electromagnetic shielding layer (80). The chip (30) is flip-chip mounted on a part of the upper surface of the flexible substrate layer (10) on a metal pad (131), and the metal enclosure (50) is disposed on another part of the metal pad (131) around the chip (30). The electromagnetic shielding layer (80) is buckled on the flexible substrate layer (10) in a cap shape, with its cap crown accommodating the chip (30) and its cap brim connected to the metal enclosure (50). The electromagnetic shielding layer (80), the metal enclosure (50) and multiple metal circuit layers in the flexible substrate layer (10) are combined, so that the chip (30) is in a metal closed space. The present invention can effectively improve the grounding and shielding effects, simplify the process, and effectively improve the production efficiency and product yield.

Description

Technical Field

[0001] The present invention relates to a packaging structure with electromagnetic shielding function and its packaging method, belonging to the technical field of semiconductor packaging. Background Art

[0002] With the rapid development of science and technology and the electronics industry, various digital and high-frequency electronic components radiate a large amount of electromagnetic waves with different frequencies and wavelengths into space during operation. Electromagnetic radiation and electromagnetic waves not only interfere with the performance realization of electronic components, but also cause serious harm to humans and other organisms. With the development of 5G technology, the demand for electromagnetic shielding devices in communication and consumer electronics continues to grow, and at the same time, the requirements for electromagnetic shielding are getting higher and higher. Therefore, electromagnetic shielding has become an essential process for electronic components, and only low-cost electromagnetic shielding solutions can be popularized in consumer electronic products. Currently, the electromagnetic shielding solutions usually use five-sided arranged electromagnetic shielding materials on the upper surface and four side walls of the product. After cutting a single product, the operation of the electromagnetic shielding layer needs to be carried out on the surface of the single product. This operation process is relatively long, and the utilization rate of the electromagnetic shielding layer material is relatively low, resulting in high costs; the side needs to make a whole electromagnetic shielding layer, and the bonding force at the joint with the bottom surface is prone to be weak, affecting the performance and reliability of the product; at the same time, the weak bonding force phenomenon will cause loss of product yield. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above packaging structure, and provide a packaging structure with electromagnetic shielding function and its packaging method that can shorten the process flow through overall operation, improve the bonding force and reliability of the electromagnetic shielding layer, and meet the integration of device packaging.

[0004] The purpose of the present invention is achieved as follows:

[0005] A packaging structure with electromagnetic shielding function of the present invention includes a flexible substrate layer, a chip, a metal enclosure, a plastic encapsulation layer, and an electromagnetic shielding layer.

[0006] The flexible substrate layer includes a dielectric layer and an internal circuit of the flexible substrate. The surface of the uppermost metal of the internal circuit of the flexible substrate exposes the upper surface of the dielectric layer to form an upper metal pad; the surface of the lowermost metal of the internal circuit of the flexible substrate exposes the lower surface of the dielectric layer to form a lower metal pad.

[0007] The chip is flip-chip mounted on a part of the upper metal pads on the upper surface of the flexible substrate layer, and the metal enclosure is disposed on another part of the upper metal pads around the chip.

[0008] The electromagnetic shielding layer is in a cap shape and buckles above the flexible substrate layer, including a cap crown and a cap brim. The cap crown accommodates the chip, and the cap brim is connected to the metal enclosure. The electromagnetic shielding layer, the metal enclosure, and the multiple metal circuit layers in the flexible substrate layer are combined to place the chip in a metal enclosed space, and the encapsulant coating layer fills this enclosed space.

[0009] Optionally, the chip is single or more than two.

[0010] Optionally, metal bumps are provided on the front surface of the chip, and the chip is flip-chip mounted on the upper surface of the flexible substrate layer through the metal bumps and connected to some of the upper metal pads thereof.

[0011] Optionally, the metal enclosure is distributed around the chip, and its material is a synthesis of one or several metal materials such as gold, silver, copper, nickel, tin, and aluminum.

[0012] Optionally, external pin metal bumps are provided on the lower metal pads of the flexible substrate layer.

[0013] Optionally, the external pin metal bumps are solder balls, solder blocks, or micro metal bumps.

[0014] Optionally, the material of the electromagnetic shielding layer is a synthesis of one or several metal materials such as gold, silver, copper, tin, aluminum, and chromium.

[0015] The encapsulation method of an encapsulation structure with electromagnetic shielding function according to the present invention has the following technological steps:

[0016] Step 1: Take a glass carrier plate, and form a laser-responsive layer on its surface by coating a laser-sensitive material.

[0017] Step 2: On the upper surface of the laser-responsive layer, through the redistribution process, stack the insulating layer and the metal layer layer by layer on the laser-responsive layer to complete the flexible substrate layer of the circuit structure, and set alignment marks.

[0018] Step 3: On the surface area of the flexible substrate layer, form a metal enclosure by electroplating. The formed metal enclosure is 30 - 1000 microns away from the chip edge and is connected to the circuit inside the flexible substrate around the device.

[0019] Step 4: Mount the chip on the flexible substrate layer by the flip-chip mounting method. The mounted chip is connected to the circuit inside the flexible substrate through metal bumps, and the mounting positioning of the flip-chip refers to the alignment marks.

[0020] Step 5: Perform encapsulant coating on the surface and periphery of the product to form an encapsulant coating layer, and the encapsulant coating layer fills the interconnect area of the chip and the flexible substrate at the same time.

[0021] Step Six: Through the action of laser, the laser-responsive layer on the glass carrier is acted upon to release the bonding force between the laser-responsive layer and the flexible substrate layer, and the glass carrier is removed;

[0022] Step Seven: Flip it 180 degrees up and down to form external pin metal bumps of the component on the lower surface of the flexible substrate layer;

[0023] Step Eight: Flip it 180 degrees up and down again, and use a grooving method to groove on the encapsulant coating surface of the product; The grooving position is aligned with the position alignment mark on the back of the flexible substrate layer; After grooving, the exposed width of the metal enclosure is 15 - 1000 microns;

[0024] Step Nine: On the surface of the product, through sputtering, spraying, printing or chemical vapor deposition, an electromagnetic shielding layer is formed on the surface of the encapsulant coating layer and the exposed surface of the metal enclosure, and the electromagnetic shielding layer is formed by sputtering, coating or printing;

[0025] Step Ten: The semi-finished product after encapsulation and grooving is cut into single products to form independent components. The positioning during cutting into single products also refers to the alignment marks on the flexible substrate layer.

[0026] Optionally, the alignment marks are in a cross shape, a square shape or an "L" shape.

[0027] Beneficial Effects

[0028] 1. The present invention forms an electromagnetic shielding layer for the overall product at one time. Without increasing the cost of the packaging structure, through the overall operation of the wafer-level product, the product yield is effectively improved, the operation procedures and steps are reduced, the process steps are simplified, and the cost of the electromagnetic shielding process is effectively reduced;

[0029] 2. The side metal enclosures are effectively utilized to enable the electromagnetic shielding layer to form a good combination with the metal enclosures. At the same time, by using the structure of the flexible substrate, the grounding performance and the electromagnetic shielding effect are effectively guaranteed;

[0030] 3. The flexible characteristics of the ultra-high density substrate are fully utilized to improve the reliability of the packaging, which is beneficial to the improvement of the product yield. Description of the Drawings

[0031] Figure 1 It is a schematic cross-sectional view of the packaging structure with electromagnetic shielding function of the present invention;

[0032] Figure 2 It is Figure 1 a schematic diagram of the metal enclosure of;

[0033] Figures 3A to 3L It is a schematic flow chart of the packaging method of the embodiment of the present invention;

[0034] Wherein:

[0035] Flexible substrate layer 10

[0036] Dielectric layer 11

[0037] Inner circuit of flexible substrate 13

[0038] Upper metal pad 131

[0039] Lower metal pad 133

[0040] External pin metal bump 18

[0041] Chip 30

[0042] Metal bump 31

[0043] Metal enclosure 50

[0044] Plastic encapsulation layer 60

[0045] Glass carrier plate 70

[0046] Laser-responsive layer 71

[0047] Electromagnetic shielding layer 80. Detailed implementation manners

[0048] An encapsulation structure with electromagnetic shielding function according to the present invention, as Figure 1 shown, which includes a flexible substrate layer 10, a chip 30, a metal enclosure 50, a plastic encapsulation layer 60 and an electromagnetic shielding layer 80. The flexible substrate layer 10 includes a dielectric layer 11 and an inner circuit of flexible substrate 13. The inner circuit of flexible substrate 13 is formed by several layers of dielectric layers and several layers of metal circuit designs and forms a telecommunication path. The dielectric material of the dielectric layer 11 fills the gap between adjacent metal circuit layers to play an insulating and protective role. The flexible substrate layer 10 has a thin thickness, which can be as thin as 25 microns at the thinnest, and it is flexible and can be folded and bent arbitrarily. The flexible substrate layer 10 has a high integration degree and excellent electrical performance, and has more advantages in mechanical performance and electrical performance compared with the same type of circuit board.

[0049] The surface of the uppermost layer of metal in the inner circuit 13 of the flexible substrate exposes the upper surface of the dielectric layer 11 to form an upper metal pad 131; the surface of the lowermost layer of metal in the inner circuit 13 of the flexible substrate exposes the lower surface of the dielectric layer 11 to form a lower metal pad 133. Metal bumps 31 with a copper bump plus a tin cap structure or a solder ball structure are provided on the front surface of the chip 30. The chip 30 is flip-chip mounted on the upper surface of the flexible substrate layer 10 through the metal bumps 31 and connected to some of its upper metal pads 131, realizing the electrical connection between the chip 30 and the flexible substrate layer 10. The chip 30 can be single, two, or more than two. Metal enclosures 50 are provided on some of the upper metal pads 131 around the chip 30. The height of the metal enclosures 50 is 50 to 1000 microns, the width is 30 to 1000 microns, they are distributed around the chip 30, and the distance from the edge of the chip 30 is 30 to 1000 microns. Metals such as gold, silver, copper, nickel, tin, aluminum, or alloys of the above metals can be used, such as Figure 2 shown, which is a top view schematic diagram of the metal enclosure.

[0050] External pin metal bumps 18 are provided on the lower metal pads 133 of the flexible substrate layer 10. The external pin metal bumps 18 can be solder balls, solder blocks, or micro metal bumps. The electromagnetic shielding layer 80 is buckled on top of the chip 30 in a cap shape, and its brim is connected to the metal enclosure 50. The thickness of the electromagnetic shielding layer 80 is 100 to 300 microns. The material of the electromagnetic shielding layer 80 can be synthesized from one or several metal materials such as gold, silver, copper, tin, aluminum, chromium, etc. The electromagnetic shielding layer 80, the metal enclosure 50, and the multiple metal circuit layers in the flexible substrate layer 10 are combined to make the chip 30 in a metal enclosed space, achieving the effect of electromagnetic shielding; then grounding is realized through the external pin metal bumps 18 provided below the flexible substrate layer 10. The enclosed space is filled with encapsulant to form an encapsulant coating layer 60.

[0051] The encapsulation method of an encapsulation structure with electromagnetic shielding function according to the present invention has the following specific implementation steps for the process:

[0052] Step 1: Take a circular glass carrier 70 with a thickness of 200 mm or 300 mm, and form a laser-responsive layer 71 on its surface by coating a laser-sensitive material, as Figure 3A and Figure 3B shown;

[0053] Step 2: Through a redistribution process on the upper surface of the laser-responsive layer 71, stack the insulating layer and the metal layer layer by layer on the laser-responsive layer 71 to complete the flexible substrate layer 10 of the circuit structure, and set alignment marks 41. The alignment marks 41 are in a cross shape, a square shape, or an "L" shape, as Figure 3C shown, and the alignment marks 41 are as Figure 3E shown in; among them, the flexible substrate layer 10 is designed according to the actual functional requirements of the product;

[0054] Step 3. On the surface area of the flexible substrate layer 10, a metal enclosure 50 is formed by electroplating. The formed metal enclosure 50 is 30 to 1000 microns away from the edge of the chip 30 and is connected to the internal circuit 13 of the flexible substrate around the chip 30, as Figure 3D and 3E shown;

[0055] Step 4. The chip 30 is mounted on the flexible substrate layer 10 by means of flip-chip mounting. The mounted chip 30 is connected to the internal circuit 13 of the flexible substrate through metal bumps 31, as Figure 3F shown. The mounting positioning of the flip-chip 30 refers to the alignment mark 41;

[0056] Step 5. The surface and periphery of the product are coated with molding compound to form a molding compound coating layer 60; Optionally, the bottom filling method is used to form bottom filling in the interconnect area between the chip 30 and the flexible substrate, and then the product is completed with molding compound coating, as Figure 3G shown;

[0057] Step 6. Through the action of laser, the laser-responsive layer 71 on the glass carrier is acted on to release the bonding force between the laser-responsive layer 71 and the flexible substrate layer 10, and the glass carrier 70 is removed, as Figure 3H shown;

[0058] Step 7. Flip 180 degrees up and down to form external pin metal bumps 18 of the component on the lower surface of the flexible substrate layer 10, as Figure 3I shown;

[0059] Step 8. Flip 180 degrees up and down again, and use the grooving method to groove the molding compound coating surface of the product; The grooving position refers to the position alignment mark 41 on the back of the flexible substrate layer 10; After grooving, the exposed width of the metal enclosure 50 is 15 to 1000 microns, as Figure 3J shown;

[0060] Step 9. On the surface of the product, an electromagnetic shielding layer 80 is formed on the surface of the molding compound coating layer 60 and the exposed surface of the metal enclosure 50 by sputtering, spraying, printing or chemical vapor deposition, as Figure 3K shown;

[0061] Step 10. The semi-finished product after encapsulation and grooving is cut into single products to form independent components, as Figure 3L shown. The positioning during cutting into single pieces also refers to the alignment mark 41 on the flexible substrate layer 10 as a reference.

[0062] The specific embodiments described above further elaborate in detail the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An encapsulation structure with electromagnetic shielding function, characterized in that, It includes a flexible substrate layer (10), a chip (30), a metal enclosure (50), a molding compound coating layer (60), and an electromagnetic shielding layer (80). The flexible substrate layer (10) includes a dielectric layer (11) and an internal circuit of the flexible substrate (13). The surface of the uppermost metal of the internal circuit of the flexible substrate (13) exposes the upper surface of the dielectric layer (11) to form an upper metal pad (131); the surface of the lowermost metal of the internal circuit of the flexible substrate (13) exposes the lower surface of the dielectric layer (11) to form a lower metal pad (133). The chip (30) is flip-chip mounted on a part of the upper metal pads (131) on the upper surface of the flexible substrate layer (10). The metal enclosure (50) is disposed on another part of the upper metal pads (131) around the chip (30). The metal enclosure (50) is distributed around the chip (30). The electromagnetic shielding layer (80) is buckled on the flexible substrate layer (10) in a cap shape, including a cap crown and a cap brim. Its cap crown accommodates the chip (30), and its cap brim is connected to the metal enclosure (50). The electromagnetic shielding layer (80), the metal enclosure (50), and multiple metal circuit layers in the flexible substrate layer (10) are combined to make the chip (30) in a metal closed space. The molding compound coating layer (60) fills the closed space. A part of the metal enclosure (50) is covered by the molding compound coating layer (60), and the width of the metal enclosure (50) exposed from the molding compound coating layer (60) is 15 - 1000 microns. The electromagnetic shielding layer (80) continuously covers the surface of the molding compound coating layer (60) and the exposed surface of the metal enclosure (50).

2. The encapsulation structure according to claim 1, wherein The chip (30) is single or two or more.

3. The encapsulation structure according to claim 1 or 2, wherein Metal bumps (31) are arranged on the front surface of the chip (30), and the chip (30) is flip-chip mounted on the upper surface of the flexible substrate layer (10) and connected to its part of the upper metal pads (131) through the metal bumps (31).

4. The encapsulation structure according to claim 1 or 2, wherein The material of the metal enclosure (50) is a synthesis of one or several metal materials of gold, silver, copper, nickel, tin, and aluminum.

5. The encapsulation structure according to claim 1, wherein External pin metal bumps (18) are arranged on the lower metal pads (133) of the flexible substrate layer (10).

6. The encapsulation structure according to claim 5, wherein, The external pin metal bumps (18) are solder balls, solder blocks, or micro metal bumps.

7. The encapsulation structure according to claim 1, characterized in that The material of the electromagnetic shielding layer (80) is a synthesis of one or several metal materials of gold, silver, copper, tin, aluminum, and chromium.

8. A packaging method for a packaging structure with electromagnetic shielding function, and its technological steps are as follows: Step 1: Take a glass carrier (70), and form a laser-responsive layer (71) on its surface by coating a laser-sensitive material. Step 2: On the upper surface of the laser-responsive layer (71), through a redistribution process, stack an insulating layer and a metal layer layer by layer on the laser-responsive layer to complete the flexible substrate layer (10) of the circuit structure, and set alignment marks (41). Step 3: On the surface area of the flexible substrate layer (10), form a metal enclosure (50) by electroplating. The formed metal enclosure (50) is 30 to 1000 micrometers away from the edge of the chip (30), is connected to the internal circuit (13) of the flexible substrate around the device, and the metal enclosure (50) is distributed around the chip (30). Step 4: Mount the chip (30) on the flexible substrate layer (10) by means of flip-chip mounting. The mounted chip (30) is connected to the internal circuit (13) of the flexible substrate through metal bumps (31), and the mounting positioning of the flip-chip (30) refers to the alignment mark (41). Step 5: Perform encapsulant coating on the surface and periphery of the product to form an encapsulant coating layer (60). The encapsulant coating layer (60) simultaneously fills the interconnect area between the chip (30) and the flexible substrate. Step 6: Act on the laser-responsive layer (71) on the glass carrier by laser to release the bonding force between the laser-responsive layer (71) and the flexible substrate layer (10), and remove the glass carrier (70). Step 7: Flip 180 degrees up and down to form external pin metal bumps (18) of the component on the lower surface of the flexible substrate layer (10). Step 8: Flip 180 degrees up and down again, and use a grooving method to groove on the encapsulant-coated surface of the product; the grooving position refers to the position alignment mark (41) on the back of the flexible substrate layer (10); after grooving, the width of the exposed metal enclosure (50) is 15 to 1000 micrometers. Step 9: On the surface of the product, form an electromagnetic shielding layer (80) on the surface of the encapsulant coating layer (60) and the exposed surface of the metal enclosure (50) by sputtering, spraying, printing or chemical vapor deposition. Part of the metal enclosure (50) is covered by the encapsulant coating layer (60), and the electromagnetic shielding layer (80) continuously covers the surface of the encapsulant coating layer (60) and the exposed surface of the metal enclosure (50). The electromagnetic shielding layer (80) is formed by sputtering, coating or printing. Step 10: Cut the semi-finished product after encapsulation and grooving into single products to form independent components. The positioning during cutting into single products also refers to the alignment mark (41) on the flexible substrate layer (10).

9. The encapsulation method according to claim 8, wherein The alignment mark (41) is in the shape of a cross, a square or an "L".

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