Novel substrate structure with high thermal conductivity and high density

Abstract

The invention discloses a novel substrate structure with high thermal conductivity and high density, and relates to a novel packaging substrate structure. In current production, a substrate material is usually epoxy resin, and multi-layer wiring needs to be adopted in order to reduce electromagnetic serial winding. However, the heat conductivity coefficient of the epoxy resin is low, so that the junction temperature and local temperature rise of the chip are too high, the chip fails, and the service life is shortened. A novel substrate structure with high thermal conductivity and high density comprises a chip, a metal layer, a BGA welding spot, an AIN plate, an FR4 plate, a linear welding spot and a bonding pad. The novel substrate is formed by combining an FR4 board and an AIN board, and the FR4 board and the AIN board are connected through linear welding spots and bonding pads to transmit electric signals. The high-heat-conductivity high-power LED lamp is characterized in that the heat conductivity coefficient of the AIN board is high and can reach more than 170W, and the FR4 board can realize multi-layer wiring, so that the cost is low. The novel substrate structure formed by combining the FR4 board and the AIN board can realize multi-layer wiring while enabling the chip to rapidly dissipate heat, so that the cost is reduced. Therefore, the device has certain scientific and engineering significance, and the structure is wide in application prospect, simple, compact and reliable in work.

Description

Technical Field

[0001] The invention relates to a novel substrate structure with high thermal conductivity and high density. Background Art

[0002] The substrate can provide electrical connection, protection, support, heat dissipation, assembly and other functions for the chip to achieve multi-pin, reduce the size of the packaged product, improve electrical performance and heat dissipation, ultra-high density or multi-chip modularization. In recent years, people have paid more and more attention to the semiconductor packaging substrate industry. The epidemic has brought about digital transformation, and a large number of fast communication technologies such as 5G have gradually arrived, which have promoted the rapid expansion of demand for packaging substrates (high-performance CPUs and AI chips for high-end servers). It is predicted that the packaging substrate will maintain a double-digit growth rate of about 10% in the future. By around 2026, the market size will be twice the current size, and there is even a view that the market size will reach US$14-15 billion by then. However, the packaging substrate is moving towards high density, which also leads to problems such as heat dissipation of chips and substrates; therefore, it is of great significance to design a new substrate material with fast heat dissipation.

[0003] Traditional substrates are mainly divided into ceramic substrates and organic laminate substrates. Ceramic substrates are made of aluminum oxide, aluminum nitride and other materials. Packages based on ceramic substrates are commonly used for surface mount devices, CMOS image sensors and multi-chip modules. Ceramic packages can be largely regarded as legacy technology. Although they were common on ICs in the past, they are now almost exclusively used in high-reliability applications such as military and avionics equipment.

[0004] Organic substrate materials are usually FR4 or other materials. FR4 is a glass cloth composed of epoxy resin. Organic laminate substrates are commonly used in 2.5D / 3D, flip chip and system-in-package (SiP), where the device is located on the substrate. Organic substrates are also multi-layer technologies, where at least two organic layers are separated by a metal layer. The metal layer acts as an electromigration barrier in the package. Organic substrate packages (BGA, CSP) use a small rigid substrate on which the die is wire bonded or flip chip. Most such packages use a set of balls or grounds to interface with the host PCB.

[0005] Commonly used organic substrate materials are generally epoxy resins, which can achieve multi-layer wiring and are low-cost. However, the thermal conductivity is extremely low, which will cause the chip junction temperature and local temperature rise to be too high, resulting in chip failure; therefore, existing substrates cannot meet the heat dissipation problem in the development of high-density integration. Summary of the invention

[0006] In view of the above problems, the present invention proposes a novel substrate structure with high thermal conductivity and high density, which solves the heat dissipation problem of the substrate under high density and high integration, and makes up for the slow heat dissipation of epoxy resin in the past.

[0007] In order to solve the above problems, the technical solution adopted by the present invention is:

[0008] A new substrate structure with high thermal conductivity and high density, comprising a chip (1), a metal layer (2), a BGA solder joint (3), an AIN board (4), an FR4 board (5), a linear solder joint (6), and a solder pad (7); the FR4 board (5) is a commonly used PCB board. The FR4 board (5) is characterized in that the FR4 board (5) is an annular board with a 10 mm×6 mm through hole in the center. The circuits on the FR4 board (5) are densely distributed on the annular board. The AIN board (4) is a multi-layer ceramic substrate with a size of 9.8 mm×5.8 mm, and the multi-layer circuits are evenly distributed on the AIN board (4). The AIN board (4) is connected to the FR4 board (5) through a linear solder joint structure (8); the solder joint structure consists of a linear solder joint (6) with a length of 200 um in the center and left and right solder pads (7). The solder joint structure is simple, easy to operate, and improves work efficiency. While ensuring the overall reliability of the product, it reduces the production cost.

[0009] Preferably, the FR4 board (5) is a glass fiber cloth composed of epoxy resin, which can realize multi-layer wiring, is widely used in substrate materials, and has low cost.

[0010] Preferably, the AIN board (4) has a high thermal conductivity coefficient, which is above 170W, good insulation, and can realize multi-layer wiring. The cost is relatively high, and it is mostly used in high-end products.

[0011] Preferably, the FR4 board (5) is a structure with a 10mm×6mm through hole at the center, and the AIN board (4) has a size of 9.8mm×5.8mm. The present invention provides a substrate structure with high heat dissipation and high density for the chip through a method of combining the FR4 board (5) and the AIN board (4).

[0012] Preferably, the AIN board (4) is mainly located at the lower end of the chip to quickly dissipate heat for the chip.

[0013] Preferably, the FR4 board (5) and the AIN board (4) are electrically connected and signal connected via a linear solder joint structure (8).

[0014] Preferably, the two ends of the FR4 board (5) and the AIN board (4) are connected by linear solder joints, and the other two sides are bonded by epoxy-type insulating glue. The bonding thickness of the glue is 200um. The epoxy-type glue has high bonding strength and is insulating, providing better reliability for the connection between the FR4 board (5) and the AIN board (4).

[0015] Preferably, a new substrate structure with high thermal conductivity and high density can change the size of the AIN board (2) according to the size of the chip, thereby improving reliability and reducing costs.

[0016] The present invention has the following beneficial effects:

[0017] 1. The structure of the present invention is composed of FR4 board and AIN board. The AIN board has high thermal conductivity and can achieve rapid heat dissipation of chips under high density and high integration.

[0018] 2. The FR4 board and the AIN board are connected by solder joints, which can effectively realize electrical connection and signal connection. The structure is simple, improves structural reliability and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the overall structural diagram of the novel substrate structure of the present invention;

[0020] Figure 2 A cross-sectional view of the front view of the novel substrate structure of the present invention;

[0021] Figure 3 This is a substrate diagram of the present invention, which is composed of a FR4 board and an AIN board through a solder joint structure.

[0022] Figure 4 A top view of the novel substrate structure of the present invention;

[0023] Figure 5 The overall structure diagram of the BGA packaging structure of the present invention;

[0024] Figure 6 A top view of a ring-shaped FR4 board of the novel substrate structure of the present invention;

[0025] Figure 7 A top view of an AIN board of the novel substrate structure of the present invention;

[0026] Figure 8 A top view of a linear solder joint structure of a novel substrate structure of the present invention;

[0027] Reference numerals:

[0028] 1-chip, 2-metal layer, 3-BGA solder joint, 4-AIN board, 5-FR4 board, 6-linear solder joint, 7-pad DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Figure 1As shown, the present invention designs a new substrate structure with high thermal conductivity and high density, which is composed of a chip (1), a metal layer (2), a BGA solder joint (3), an AIN board (4), an FR4 board (5), a linear solder joint (6), and a solder pad (7).

[0030] Specifically, refer to Figure 2 , Figure 3 and Figure 4 It can be seen that the novel substrate structure of the present invention is formed by combining an AIN board (4) and a FR4 board (5). Both the AIN board (4) and the FR4 board (5) are used in industrial production, but due to the influence of thermal conductivity, integration and cost, both of them cannot achieve very good results. The FR4 board (5) in the present invention is a structure with a 10mm×6mm through hole at the center, while the size of the AIN board (4) is 9.8mm×5.8mm. The AIN board (4) is placed in the hole of the FR4 board (5), and the two ends are connected with solder joints to provide signal connection for the substrate; the other two ends are bonded with insulating glue to improve the reliability of substrate interconnection. In addition, the multi-layer wiring of the AIN board (4) has a long delivery cycle and a high cost; however, the FR4 board (5) can realize multi-layer wiring and has a low cost. The wiring in the AIN board (4) in the present invention only serves to connect the chip with the circuit in the FR4 board (5), so the circuit in the AIN board (4) will be relatively simple and the cost will be greatly reduced.

[0031] In the package, the chip is usually in the middle and the heat caused by the chip operation is the highest; combined with Figure 2 , Figure 5 and Figure 7 It can be seen that the AIN board (4) in the present invention is located below the chip, which can minimize the problem of heat causing malfunctions on the chip.

[0032] Combination Figure 3 and Figure 8 It can be seen that the FR4 board (5) and the AlN board (4) are electrically connected and signal transmitted through the linear solder joint structure (8); the connection structure is composed of solder joints (6) and pads (7). In the connection structure welding step, the connection structure between the FR4 board (1) and the AlN board (2) is welded by an automatic spot welding machine. The solder joints between the FR4 board (5) and the AlN board (4) use lead-free solders such as Sn3.0Ag0.5Cu and Sn58Bi, and the pads use Cu.

[0033] above Figure 1 The new substrate structure with high thermal conductivity and high density shown is a specific embodiment of the present invention, which has embodied the substantial characteristics and progress of the present invention. According to actual use needs and under the guidance of the present invention, equivalent modifications in shape, structure, etc. can be made to it, which are all within the protection scope of this scheme.

Claims

1. A new type of substrate structure with high thermal conductivity and high density, comprising a chip (1), a metal layer (2), a BGA solder joint (3), an AIN board (4), an FR4 board (5), a linear solder joint (6), and a pad (7); the chip (1), the metal layer (2), and the BGA solder joint (3) are a BGA package structure, characterized in that the BGA has a small size, a large memory capacity, good electrical performance, and good heat dissipation. The FR4 board (5) is a commonly used PCB board. The FR4 board (5) is characterized in that the FR4 board (5) is an annular board with a 10 mm×6 mm through hole in the center. The circuits on the FR4 board (5) are densely distributed on the annular board. The AIN board (4) is a multi-layer ceramic substrate with a size of 9.8 mm×5.8 mm, and the multi-layer circuits are evenly distributed on the AIN board (4). The AIN board (4) is connected to the FR4 board (5) through a linear solder joint structure (8); the solder joint structure is composed of a linear solder joint (6) with a length of 200 um in the center and left and right pads (7). The solder joint has a simple structure and is easy to operate, which improves work efficiency and reduces production costs while ensuring the overall reliability of the product.

2. A novel substrate structure with high thermal conductivity and high density according to claim 1, characterized in that: The FR4 board (5) is a glass fiber cloth composed of epoxy resin, which can realize multi-layer wiring, is widely used in substrate materials, and has low cost.

3. A novel substrate structure with high thermal conductivity and high density according to claim 1, characterized in that: The AIN board (4) has a high thermal conductivity of more than 170W, good insulation, and can realize multi-layer wiring. It is relatively accurate during printing, patching, and welding. It has good chemical stability, and is better than general circuit substrates in terms of shock resistance, heat resistance, pressure resistance, internal circuits, MARK points, etc.

4. A novel substrate structure with high thermal conductivity and high density according to claim 1, characterized in that: The FR4 board (5) is a structure with a 10mm×6mm through hole at the center, and the size of the AIN board (4) is 9.8mm×5.8mm. The structure combines the FR4 board (5) with the AIN board (4), utilizing the advantages of the high thermal conductivity of the AIN board (4) and the multi-layer wiring of the FR4 board (5), thereby providing a guarantee for a high-density and high-integration substrate.

5. A novel substrate structure with high thermal conductivity and high density according to claim 4, characterized in that: The middle part of the entire substrate is made of ceramic, and the edge part is made of organic substrate. In the package, the chip is usually in the middle, and the heat caused by the chip operation is the most; so the substrate material at the bottom of the chip is ceramic, which can minimize the reliability problems caused by heat.

6. A novel substrate structure with high thermal conductivity and high density according to claim 5, characterized in that: The shapes and sizes of the FR4 board (5) and the AIN board (4) can be changed according to working conditions.

7. A novel substrate structure with high thermal conductivity and high density according to claim 5, characterized in that: The FR4 board (5) and the AIN board (4) are electrically connected and signal connected via a linear solder joint structure (8).

8. A novel substrate structure with high thermal conductivity and high density according to claim 7, characterized in that: The two ends of the FR4 board (5) and the AIN board (4) are connected by linear solder joints, and the other two sides are bonded by epoxy-type insulating glue. The bonding thickness of the glue is 200um. The epoxy-type glue has high bonding strength and is insulating, providing better reliability for the connection between the FR4 board (5) and the AIN board (4).

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