A system-level double-sided fan-out packaging structure processing method using an aluminum substrate

Abstract

The present invention provides a method for processing a system-level double-sided fan-out packaging structure using an aluminum substrate, comprising: using an aluminum alloy substrate as a bottom plate; making a double-sided cavity mask on the aluminum alloy substrate and performing a non-penetrating anodization on the substrate; making a structural and functional integrated carrier by selectively penetrating aluminum anodization and the anisotropic etching characteristics of anodized aluminum; mounting chips in the cavity of the structural and functional integrated carrier and wiring on the surface of the carrier; making a redistribution layer on the surface of the carrier; completely encapsulating one side of the carrier with epoxy plastic encapsulant and planting balls on the other side to form a system-level double-sided fan-out packaging structure. The method of the present invention uses an aluminum anodized structural and functional integrated carrier, has the characteristics of simple process flow, low cost, high precision of the anisotropic etching processing cavity, good thermal conductivity, etc., and can improve the precision, density, support strength, heat dissipation capacity and signal transmission integrity of the chip double-sided fan-out packaging.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit chip packaging, and in particular to a method for processing a system-level double-sided fan-out packaging structure using an aluminum substrate. Background Art

[0002] With the advent of the post-Moore era, the size of integrated circuits has reached the nanometer scale and is gradually approaching its physical limits. Reducing feature size is no longer sufficient to further improve IC performance. Integrating integrated circuits through advanced packaging technology is another way to improve system performance. Traditional Fan-In packaging requires all bumps to fit within the chip size, and the number of bumps is limited by chip size. High-performance chips typically feature a large number of I / Os and high density, posing a significant challenge to packaging integration. Emerging Fan-Out packaging technology no longer relies on chip size and can be manufactured to the desired size. This means there are no restrictions on the number of bumps or the pitch between solder balls, enabling high-bandwidth data transmission and effectively addressing the issue of chip packaging being constrained by I / O density.

[0003] However, as chip integration increases, RDL redistribution layouts shrink. This makes chip bump alignment, heat dissipation, and warpage in fan-out packages challenging. Materials with excellent heat dissipation performance include metal (aluminum, copper) alloys and metal-nonmetal composites. Aluminum, with its high thermal conductivity, ease of low-cost processing, amenability to anodization, and high anisotropic etching precision for porous alumina, can improve chip alignment accuracy and heat dissipation in fan-out packages for RF microwave systems, providing a solution for reducing package warpage and lowering costs. Summary of the Invention

[0004] In response to the defects in the prior art, the purpose of the present invention is to provide a system-level double-sided fan-out packaging structure processing method using an aluminum substrate, which can effectively improve the chip's embedding accuracy, heat dissipation capability and signal transmission integrity. Through the chip's symmetrical fan-out packaging and thermally conductive metal aluminum layer, the support strength is improved, which can improve the warping problem caused by multi-layer rewiring.

[0005] According to the present invention, a method for manufacturing a system-level double-sided fan-out packaging structure using an aluminum substrate includes the following steps:

[0006] S01: Aluminum alloy substrate is used as the bottom plate;

[0007] S02: making a double-sided cavity mask on the aluminum alloy substrate, and performing a non-penetrating anodization on the substrate;

[0008] S03: Fabricate a structural and functional integrated substrate by selectively penetrating aluminum anodization and the anisotropic etching characteristics of anodized aluminum;

[0009] S04: mounting a chip in the cavity of the structural and functional integrated carrier and wiring on the surface of the carrier;

[0010] S05: fabricating a redistribution layer on the surface of the carrier board;

[0011] S06: Completely encapsulate one side of the carrier board with epoxy plastic and plant balls on the other side to form a system-level double-sided fan-out packaging structure.

[0012] Preferably, the structure-function integrated carrier board has a double-sided cavity, a heat-conducting metal aluminum layer and vertical interconnected through-pillars.

[0013] Preferably, the double-sided cavity is formed by anisotropic etching of porous alumina.

[0014] Preferably, the heat-conducting metal aluminum layer is located between two opposite cavities of the double-sided cavity.

[0015] Preferably, the heat-conducting aluminum metal layer is made of aluminum alloy, and the thickness of the heat-conducting aluminum metal layer is less than 50 microns.

[0016] Preferably, the vertical interconnection through-pillars are coaxial aluminum pillar structures, which are used to achieve complete transmission of signals between the two surfaces of the carrier board.

[0017] Preferably, the cavity is placed on the upper and lower surfaces of the carrier, and the size of the cavity is slightly larger than the size of the chip.

[0018] Preferably, the heat-conducting metal aluminum layer, the double-sided cavity and the vertical interconnection through-pillars are all formed in-situ of aluminum alloy on the base plate.

[0019] Preferably, the chip is embedded in cavities on the upper and lower surfaces of the carrier board, and is connected to the external carrier board via solder balls on one side of the packaging structure.

[0020] Preferably, the chip is interconnected with the redistribution layer, and the redistribution layers on both sides of the substrate are connected via the through-pillars of the coaxial structure.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The double-sided fan-out package structure produced by the present invention uses an aluminum-based structure with integrated functions. It has the characteristics of simple process flow, low cost, high processing precision of the cavity produced by anisotropic etching, and good thermal conductivity. It can improve the precision, density and heat dissipation capacity of the double-sided fan-out chip package.

[0023] 2. The processing method of the double-sided fan-out packaging structure implemented by the present invention can improve the integrity of signal transmission, enhance the supporting strength through the thermally conductive metal aluminum layer, improve the warping problem, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0025] Figure 1 Flowchart of a method for manufacturing a system-level double-sided fan-out packaging structure using an aluminum substrate in an embodiment of the present invention;

[0026] Figure 2 Schematic cross-sectional view of anisotropic etching of a cavity according to an embodiment of the present invention;

[0027] Figure 3 Schematic cross-sectional view of an aluminum-based carrier plate with integrated structure and function according to an embodiment of the present invention;

[0028] Figure 4 Schematic cross-sectional view of a coaxial transmission line within an aluminum-based carrier board with integrated structure and function according to an embodiment of the present invention;

[0029] Figure 5 Schematic cross-sectional view of a double-sided cavity within a functionally integrated aluminum substrate in an embodiment of the present invention;

[0030] Figure 6 is a schematic cross-sectional view of an aluminum-based system-level double-sided fan-out packaging structure according to an embodiment of the present invention; and

[0031] Figure 7 Schematic diagram of the assembly of the aluminum-based system-level double-sided fan-out packaging structure in an embodiment of the present invention.

[0032] In the picture:

[0033] 001 is an aluminum alloy substrate, 10 is an anodic oxidation pattern mask, 051 is a porous aluminum oxide dielectric, 052 is metal aluminum, 111 is a porous oxide layer heterogeneous etching solution, 002 is a structural and functional integrated carrier, 011 is a vertical interconnection column, 020 is an anodic oxidation dielectric, 021 is the outer conductor of the coaxial column, 031 is the cavity inside the carrier, 041 is a thermal conductive metal aluminum layer, 01A is the first RDL wiring on one surface of the carrier, 01B is the first RDL wiring on the other surface of the carrier, 1 3A is a chip packaged on one side, 13B is a chip packaged on the other side, 12A is a conductor for the first wiring on one side of the carrier, 12A is a dielectric for the first wiring on one side of the carrier, 12B is a conductor for the first wiring on the other side of the carrier, 14B is a dielectric for the second wiring on the other side of the carrier, 02A is a second RDL wiring on one surface of the carrier, 02B is a second RDL wiring on the other surface of the carrier, 22A is a conductor for the second wiring on one side of the carrier, 24A is a dielectric for the second wiring on one side of the carrier, 22B is a conductor for the second wiring on the other side of the carrier, 24B is a dielectric for the second wiring on the other side of the carrier, 03A is a third RDL wiring on one surface of the carrier, 03B is a third RDL wiring on the other surface of the carrier, 32A is a conductor for the third wiring on one side of the carrier, 34A is a dielectric for the third wiring on one side of the carrier, 32B is a conductor for the third wiring on the other side of the carrier, 34B is a dielectric for the third wiring on the other side of the carrier, 04A is a fourth RDL wiring on one surface of the carrier, 0 4B is the fourth RDL wiring on the other surface of the carrier, 61A is the dielectric for the fourth wiring on one side of the carrier, 62A is the conductor for the fourth wiring on one side of the carrier, 61B is the dielectric for the fourth wiring on the other side of the carrier, 62B is the conductor for the fourth wiring on the other side of the carrier, 100 is the BGA solder ball of the package junction, 101 is the re-metallization layer on the surface of the package structure, 003 is an external carrier such as a PCB board, 031 is the wiring layer inside the external carrier, 0032 is the dielectric layer inside the external carrier, and 0033 is the chip bottom filler. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0035] Figure 1 FIG. 1 is a flow chart of a method for manufacturing a system-level double-sided fan-out packaging structure using an aluminum substrate in an embodiment of the present invention. Figure 1 As shown, the system-level double-sided fan-out packaging structure processing method using an aluminum substrate provided by the present invention includes the following steps:

[0036] S01: Aluminum alloy substrate is used as the bottom plate;

[0037] S02: making a double-sided cavity mask on the aluminum alloy substrate, performing a non-penetrating anodization on the substrate to remove the oxide layer;

[0038] S03: Through selective penetration of aluminum anodizing, coaxial vertical interconnects are produced. The aluminum in the mask-protected area forms the vertical interconnects, and the aluminum in the mask-unprotected area forms a porous aluminum oxide medium. The double-sided cavity area forms a porous aluminum oxide medium with a depth matching the chip thickness. A thermally conductive metal aluminum layer with a thickness of less than 50 microns is placed between the cavities. The anisotropic etching characteristics of anodized aluminum are utilized to produce a double-sided cavity, ultimately forming a structurally and functionally integrated carrier board, including: vertical interconnected aluminum vias, double-sided cavity, thermally conductive metal aluminum layer, etc.

[0039] S04: mounting a chip in the cavity of the structural and functional integrated carrier and wiring on the surface of the carrier;

[0040] S05: Fabricating a redistribution layer (RDL) on the surface of the carrier board;

[0041] S06: a redistribution layer (RDL) is fabricated on the surface of the carrier board, one side of the carrier board is completely encapsulated with epoxy plastic, and balls are implanted on the other side to form a system-level double-sided fan-out packaging structure.

[0042] Figure 2 Schematic diagram of the anisotropic corrosion cross section of the cavity in an embodiment of the present invention, as shown in FIG. Figure 2 As shown, the aluminum oxide layer has a vertical porous structure, and the corrosive liquid can only corrode the oxide layer along the pores. Therefore, the corrosion rate in the Z direction of the substrate is significantly greater than that in the XY direction. The anisotropic corrosion of anodized aluminum oxide forms a cavity after etching the porous oxide layer, which can accurately control the processing accuracy of the buried cavity.

[0043] Figure 3 FIG. 1 is a cross-sectional diagram of a structural and functional integrated carrier board according to an embodiment of the present invention. Figure 3 As shown, it includes: a thermally conductive metal aluminum layer between the double-sided cavity, a coaxial vertical interconnection column with electromagnetic shielding function, and a double-sided symmetrical cavity. The thermally conductive metal aluminum layer dissipates the heat generated by the chip in a timely manner and can improve the supporting strength. The chip is interconnected with the redistribution layer, and the redistribution layers are connected through the coaxial vertical interconnection column.

[0044] Figure 4 Schematic diagram of the cross section of the coaxial transmission line inside the structure and function integrated carrier board according to the embodiment of the present invention, the upper part is a top view, and the lower part is a side view. Figure 4As shown, the vertical interconnected aluminum vias are surrounded by anodized aluminum dielectric, and outside the dielectric is the outer conductor metal aluminum of the coaxial transmission line. The upper and lower surfaces of the outer conductor are anodized aluminum dielectric, and its thickness is less than 50 microns.

[0045] Figure 5 FIG. 1 is a cross-sectional diagram of a double-sided cavity inside a structural and functional integrated carrier according to an embodiment of the present invention. Figure 5 As shown, there is a thermally conductive metal aluminum layer between the double-sided cavity, with a thickness of less than 50 microns, and the bottom of the cavity is an anodized aluminum medium, with a thickness of less than 10 microns.

[0046] Figure 6 FIG. 1 is a schematic cross-sectional view of a double-sided fan-out packaging structure according to an embodiment of the present invention. Figure 6 As shown, the double-sided fan-out packaging structure includes a structural and functional integrated carrier, a redistribution layer (RDL), and a chip. The structural and functional integrated carrier is placed in the middle layer of the packaging structure, the redistribution layer is placed on the carrier and chip surfaces, and the chip is embedded in the double-sided cavity of the carrier. The structural and functional integrated carrier has a thermally conductive metal aluminum layer, coaxial vertical interconnected aluminum vias for electromagnetic shielding, and a double-sided cavity. The thermally conductive metal aluminum layer dissipates heat generated by the chip in a timely manner and can improve support strength. The chip is interconnected with the redistribution layer, and the redistribution layers are connected to each other through the vertical interconnected aluminum vias. The number of wiring layers is not limited to four.

[0047] Figure 7 FIG. 1 is a schematic diagram of the final assembly of the double-sided fan-out packaging module onto a printed circuit board according to an embodiment of the present invention. Figure 7 As shown, after ball planting, the other side of the carrier is filled with glue under the chip to connect to the external carrier. During ball planting, the BGA solder balls are connected.

[0048] The present invention discloses a system-level double-sided fan-out packaging structure using an aluminum substrate and a processing method thereof, which has the characteristics of simple process and high processing precision. It can effectively improve the chip packaging precision, density and support strength, and improve the chip's heat dissipation capability and signal transmission integrity. The symmetrical fan-out packaging of the heat-conducting metal aluminum layer and the chip can improve the warping problem caused by rewiring, and can be used for fan-out packaging of radio frequency microwave systems.

[0049] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A system-level double-sided fan-out packaging structure processing method using an aluminum substrate, characterized in that: The steps include: S01: Aluminum alloy substrate is used as the bottom plate; S02: making a double-sided cavity mask on the aluminum alloy substrate, and performing a non-penetrating anodization on the substrate; S03: Through selective penetration of aluminum anodizing, coaxial vertical interconnects are produced. The aluminum in the mask-protected area forms the vertical interconnects, and the aluminum in the mask-unprotected area forms a porous aluminum oxide medium. The double-sided cavity area forms a porous aluminum oxide medium with a depth matching the chip thickness. There is a thermally conductive metal aluminum layer between the cavities. The anisotropic etching characteristics of anodized aluminum are utilized to produce a double-sided cavity, forming a structural and functional integrated carrier. The heat-conducting aluminum layer between the double-sided cavities, the coaxial vertical interconnection columns with electromagnetic shielding function, and the double-sided symmetrical cavities, the heat-conducting aluminum layer dissipates the heat generated by the chip in a timely manner; S04: mounting a chip in the cavity of the structural and functional integrated carrier and wiring on the surface of the carrier; S05: manufacturing a redistribution layer on the surface of the carrier board, interconnecting the chip and the redistribution layer, and connecting the redistribution layers through the coaxial vertical interconnection columns; S06: Completely encapsulate one side of the carrier board with epoxy plastic and plant balls on the other side to form a system-level double-sided fan-out packaging structure.

2. The method for processing a system-level double-sided fan-out packaging structure using an aluminum substrate according to claim 1, wherein: The double-sided cavity is formed by anisotropic etching of porous alumina.

3. The method for processing a system-level double-sided fan-out packaging structure using an aluminum substrate according to claim 1, wherein: The heat-conducting aluminum layer is located between two opposite cavities of the double-sided cavity.

4. The method for processing a system-level double-sided fan-out packaging structure using an aluminum substrate according to claim 3, wherein: The heat-conducting aluminum metal layer is made of aluminum alloy, and the thickness of the heat-conducting aluminum metal layer is less than 50 microns.

5. The method for manufacturing a system-level double-sided fan-out packaging structure using an aluminum substrate according to claim 1, wherein: The vertical interconnection through-pillar is a coaxial aluminum pillar structure, which is used to achieve complete transmission of signals on the two surfaces of the carrier board.

6. The method for manufacturing a system-level double-sided fan-out packaging structure using an aluminum substrate according to claim 3, wherein: The cavity is placed on the upper and lower surfaces of the carrier board, and the size of the cavity is slightly larger than the size of the chip.

7. The method for manufacturing a system-level double-sided fan-out packaging structure using an aluminum substrate according to claim 1, wherein: The heat-conducting metal aluminum layer, the double-sided cavity, and the vertical interconnection through-pillars are all formed in-situ of aluminum alloy on the bottom plate.

8. The method for manufacturing a system-level double-sided fan-out packaging structure using an aluminum substrate according to claim 1, wherein: The chip is embedded in the cavity on the upper and lower surfaces of the carrier board and is connected to the external carrier board through the solder balls on one side of the packaging structure.

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