Power chip embedded PCB type power module and preparation method thereof

Abstract

The application belongs to the technical field, and particularly relates to a power chip embedded PCB type power module and a preparation method thereof. The power chip embedded PCB type power module of the application embeds a plastic package formed by plastic packaging a ceramic copper-clad substrate in advance into an embedding hole of a core plate, only needs to fill the gap between the plastic package and the embedding hole, greatly reduces the epoxy resin filling amount, simplifies the PCB processing technology, reduces the probability of process problems such as cavities and incomplete filling, and improves the product flatness and yield. Meanwhile, the plastic package has a certain protective effect on the internal ceramic layer, avoids direct exposure of the ceramic layer, reduces the internal stress of the ceramic layer, and reduces the risk of cracking of the ceramic layer. Meanwhile, the lower surface of the lower copper layer of the ceramic copper-clad substrate is directly exposed to the embedding hole, and there is no need to additionally press the PCB material layer on the bottom layer, which reduces the overall thermal resistance, improves the heat dissipation efficiency, reduces the cyclic thermal stress generated between the PCB material and the ceramic copper-clad substrate due to the mismatch of the thermal expansion coefficients, avoids the insulation failure problem caused by the stress cracking of the ceramic layer, and improves the service life and reliability of the product.

Description

Technical Field

[0001] This invention belongs to the technical field, specifically relating to a power chip embedded in a PCB power module and its fabrication method. Background Technology

[0002] As applications demand increasingly higher power levels, smaller size and weight, and lower costs, traditional plastic and potting packages for power modules are becoming increasingly inadequate. Encapsulating power chips within PCB modules, utilizing PCB technology for electrical interconnection and insulation, not only significantly reduces stray inductance but also reduces module size. There are two main approaches to using PCB-packaged power modules.

[0003] One is the Cell solution, such as Figure 1 Cell refers to a copper block with grooves. The chip is embedded in the grooves, and then the copper block is embedded into the core board of the PCB. Then, the prepreg layer and each copper layer are pressed together with the core board one by one using PCB technology. Electrical interconnection is achieved on both the top and bottom using PCB technology. This solution is structurally symmetrical, so the warpage of the finished product is small. However, the insulating heat dissipation layer (PP layer) is made of organic materials with low thermal conductivity (<10W / mK), resulting in limited heat dissipation efficiency. At the same time, the insulating properties of organic polymer materials will decay rapidly in high-temperature environments, affecting the product's lifespan.

[0004] Another approach uses a ceramic copper-clad substrate, such as Figure 2 The overall structure is similar to the Cell solution, but a ceramic copper-clad substrate is used instead of a Cell. The ceramic copper-clad substrate has a sandwich structure consisting of an upper copper layer, a ceramic layer, and a lower copper layer. The chip is mounted on the ceramic copper-clad substrate and then embedded in the PCB's core board. Because the ceramic layer protrudes slightly relative to the upper and lower copper layers in its structure, there is a large gap between the ceramic copper-clad substrate and the core board after embedding. This gap needs to be filled with epoxy resin, and then PCB-related processes are used to laminate the upper and lower layers with prepreg, copper layers, etc.

[0005] Unlike the Cell solution, Solution 2 uses a ceramic layer for insulation and heat dissipation instead of organic polymer materials. Due to the high thermal conductivity of ceramic layers (e.g., Si3N4 ceramic substrates can reach 90W / mK), its heat dissipation efficiency is better. The top layer uses PCB technology for electrical interconnection. To achieve structural symmetry, the bottom layer also uses prepreg and copper layers of the same thickness and number of layers, with copper vias between the copper layers to achieve better heat conduction efficiency. However, the heat dissipation effect of this solution is still inferior to traditional power modules that directly use ceramic copper-clad laminates. PCB materials generally have a high coefficient of thermal expansion, especially the epoxy resin filling the ceramic copper-clad laminate. The ceramic layer material is brittle, and during reliability testing and subsequent application, cyclic thermal stress can easily cause cracks in the ceramic layer of the ceramic copper-clad laminate, leading to insulation failure. Furthermore, due to the inherent characteristics of the ceramic copper-clad laminate, when embedded in the PCB core board, there are many voids around it, requiring a large amount of epoxy resin adhesive for filling. This process is unfriendly to the PCB manufacturing process and can easily lead to incomplete filling in other areas, resulting in an uneven finished product.

[0006] The foregoing statements are for informational purposes only and are not intended to provide background information in connection with this application. Unless otherwise stated herein, the content described in this section is not prior art to the rest of this application. Summary of the Invention

[0007] The purpose of this invention is to provide a power chip embedded in a PCB power module and its fabrication method.

[0008] This application provides a power chip embedded in a PCB type power module, including: The core board has embedded holes that penetrate the upper and lower surfaces. A molding compound is disposed within the embedding hole; the molding compound includes a ceramic copper-clad substrate and molding compound disposed on the peripheral and upper sides of the ceramic copper-clad substrate; the lower surface of the lower copper layer of the ceramic copper-clad substrate is exposed in the embedding hole. Several layers of prepreg and PCB copper are alternately arranged on the upper part of the core board; and The solder mask layer is located on the top side of the copper layer of the PCB.

[0009] In one embodiment of this application, the ceramic copper-clad substrate includes an upper copper layer, a ceramic layer, and a lower copper layer disposed sequentially from top to bottom; The thickness of the lower copper layer is greater than that of the upper copper layer.

[0010] In one embodiment of this application, the thickness of the lower copper layer is 10%-50% greater than the thickness of the upper copper layer.

[0011] In one embodiment of this application, a chip is connected to several regions on the upper surface of the copper overlay.

[0012] In one embodiment of this application, the molding compound on the upper surface of the copper overlay layer is provided with a plurality of chip slots; The chip is located in a chip slot, with a gap of 75-250µm between the chip and the edge of the chip slot, and the upper surface of the chip is 10-50µm lower than the upper surface of the molding compound.

[0013] In one embodiment of this application, several regions on the upper surface of the copper overlay are connected to copper sheets.

[0014] In one embodiment of this application, the PCB copper layers are connected to each other, between the PCB copper layers and the chip, and between the PCB copper layers and the copper sheet through copper vias.

[0015] Accordingly, this application provides a method for fabricating a power chip embedded in a PCB power module as described above, comprising: Prepare a molding compound with an exposed copper overlay on the lower surface; The molding compound is embedded in the embedding hole of the core board, and the lower surface of the underlying copper layer is exposed in the embedding hole; The upper layer structure of the core board is prepared to obtain the PCB motherboard; The PCB motherboard is cut apart, and the core board on the outside of the plastic encapsulation is removed to obtain the final product.

[0016] In one embodiment of this application, the molding compound with an exposed lower copper layer on its lower surface comprises: Prepare a ceramic copper-clad substrate with a lower copper layer thickness greater than the upper copper layer; Then, the areas where the copper layer needs to be sintered with the chip and / or copper sheet are treated with a silver plating layer. If a soldering process is used, no additional treatment is required. Copper sheets are sintered or welded at the appropriate locations as needed; The ceramic copper-clad substrate is encapsulated by wrapping the periphery and top of the ceramic copper-clad substrate with encapsulating material, exposing the lower surface of the lower copper layer, and the soldering or sintering position of the upper copper layer chip is also exposed, forming a groove larger than the chip. Grind away a portion of the thickness from the top surface of the molded body to remove the molding compound from the surface of the copper sheet and expose it; The chip is soldered or sintered onto the copper overlay.

[0017] In one embodiment of this application, the fabrication of the core plate upper layer structure includes: The prepreg layer and the PCB copper layer are laminated onto the core board; Laser drilling is performed at appropriate locations, followed by electroplating to fill the holes and form copper through-holes for electrical connections. The laminated PCB copper layer is divided into multiple pieces according to functional requirements; The above steps can be performed once or repeated multiple times as needed; during the pressing process, epoxy resin fills the gap between the core plate and the encapsulant; Next, apply a solder resist layer to cover the parts that need to be electrically connected to the outside, leaving the windows open for soldering terminals or other components.

[0018] The beneficial effects of this invention are: The power chip embedded in the PCB power module of this invention pre-encapsulates the ceramic copper-clad substrate to form a molded body before embedding it into the embedding hole of the core board. Only the gap between the molded body and the embedding hole needs to be filled, significantly reducing the amount of epoxy resin filler, simplifying the PCB processing, reducing the probability of process problems such as voids and incomplete filling, and improving product flatness and yield. Simultaneously, the molding compound provides some protection to the internal ceramic layer, preventing it from being directly exposed, reducing internal stress in the ceramic layer, and lowering the risk of cracking. Furthermore, in this invention, the lower surface of the lower copper layer of the ceramic copper-clad substrate is directly exposed to the embedding hole, eliminating the need for an additional PCB material layer. This reduces overall thermal resistance, improves heat dissipation efficiency, and reduces cyclic thermal stress caused by the mismatch in thermal expansion coefficients between the PCB material and the ceramic copper-clad substrate, preventing insulation failure caused by stress cracking of the ceramic layer, and improving product lifespan and reliability.

[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of existing technology; Figure 2 This is a schematic diagram of existing technology; Figure 3 This is a schematic diagram of a preferred embodiment of the present invention, showing a power chip embedded in a PCB-type power module. Figure 4This is a schematic diagram of a preferred embodiment of the ceramic copper-clad substrate of the present invention; Figure 5 This is a schematic diagram of the copper sheet installation according to a preferred embodiment of the present invention; Figure 6 This is a schematic diagram of the plastic encapsulation of a preferred embodiment of the present invention; Figure 7 This is a schematic diagram of a preferred embodiment of the encapsulation body of the present invention; Figure 8 This is a schematic diagram of a preferred embodiment of the present invention, showing the encapsulated body being installed inside the core board; Figure 9 This is a schematic diagram of a preferred embodiment of the present invention, showing the prepreg layer and PCB copper layer laminated on the core board; Figure 10 This is a schematic diagram of a copper through-hole according to a preferred embodiment of the present invention; Figure 11 This is a schematic diagram of a preferred embodiment of the solder resist coating of the present invention; Figure 12 This is a schematic diagram of the finished product obtained after cutting according to a preferred embodiment of the present invention.

[0023] In the picture: Core board 1, embedded hole 11, molding compound 2, ceramic copper clad substrate 21, upper copper layer 211, ceramic layer 212, lower copper layer 213, molding compound 22, chip 23, chip groove 231, copper sheet 24, silver plating layer 25, prepreg layer 3, PCB copper layer 4, solder mask layer 5, copper through hole 6. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This application provides a power chip embedded in a PCB power module and its fabrication method, which are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, in the following embodiments, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.

[0026] See Figure 3 In one embodiment, the power chip embedded in the PCB-type power module includes: The core board 1 has an embedded hole 11 that runs through the upper and lower surfaces. A molding compound 2 is disposed within the embedding hole 11; the molding compound 2 includes a ceramic copper-clad substrate 21 and molding compound 22 disposed on the peripheral and upper sides of the ceramic copper-clad substrate 21; the lower surface of the lower copper layer 213 of the ceramic copper-clad substrate 21 is exposed in the embedding hole 11. Several layers of prepreg layer 3 and PCB copper layer 4 are alternately disposed on the upper end of core board 1; and Solder mask layer 5 is located on the upper side of the top copper layer 4 of the PCB.

[0027] In this embodiment, by exposing the lower surface of the lower copper layer 213 of the ceramic copper-clad substrate 21 to the embedded hole 11, the lower copper layer 213 can be directly used as a heat dissipation layer at the bottom of the module, without the need to add an additional PCB heat dissipation structure at the bottom, further reducing thermal resistance.

[0028] Furthermore, the ceramic copper-clad substrate 21 includes an upper copper layer 211, a ceramic layer 212, and a lower copper layer 213 arranged sequentially from top to bottom; the thickness of the lower copper layer 213 is greater than that of the upper copper layer 211.

[0029] In this embodiment, the upper process and scheme of the molding compound 2 can remain unchanged. The PCB process is still used to laminate the prepreg layer 3 and the PCB copper layer 4, and the lower PCB structure is removed. At the same time, the thickness of the upper and lower copper layers of the ceramic copper-clad substrate 21 is controlled. The thickened lower copper layer 213 can improve the overall mechanical support performance of the ceramic copper-clad substrate and further enhance the heat conduction capacity at the bottom, thereby improving the overall heat dissipation efficiency of the module. At the same time, the asymmetrical structure of the upper and lower parts of the ceramic copper-clad substrate 21 and the overall asymmetry of the power module can be mutually offset to ensure that the warpage of the final product is controlled within a reasonable range.

[0030] In some embodiments, the thickness of the lower copper clad layer 213 may be 10%-50% greater than the thickness of the upper copper clad layer 211. In some embodiments, the specific thickness values ​​of the lower copper clad layer 213 and the upper copper clad layer 211 can be adjusted according to the warping of the ceramic copper clad substrate at high temperatures, ultimately achieving a warping value within the PCB process requirements.

[0031] In some embodiments, for power modules with relatively simple structures, the upper PCB structure can be further simplified. The commonly used two layers of prepreg 3 + two layers of PCB copper 4 + solder mask 5 can be reduced to one layer of prepreg 3 + one layer of PCB copper 4 + solder mask 5. This solution can further reduce structural complexity, alleviate stress problems caused by asymmetrical structures, and further reduce process difficulty and cost.

[0032] Further, see Figure 3 The upper surface of the copper overlay 211 has several regions connected to the chip 23.

[0033] Preferably, the molding compound 22 on the upper surface of the copper overlay 211 is provided with a plurality of chip slots 231; the chip 23 is located in the chip slots 231, and the height of the upper surface of the chip 23 is lower than the height of the upper surface of the molding compound 22. This structure can not only achieve stable fixation and protection of the chip surface and surrounding area by epoxy resin in the subsequent prepreg process, but also reserve adaptation space between the chip and the upper PCB copper layer, avoiding interference with the lamination process.

[0034] Optionally, the edge gap between the chip 23 and the chip groove 231 is between 75-250um, and the height of the upper surface of the chip 23 is 10-50um lower than the height of the upper surface of the molding compound 22.

[0035] Furthermore, copper sheets 24 are connected to several areas on the upper surface of the copper overlay 211. The copper sheets 24 are used to elevate the corresponding connection positions to facilitate reliable electrical conduction with the upper PCB copper layer.

[0036] Furthermore, the PCB copper layers 4 are connected to each other, to the chip 23, and to the copper sheet 24 via copper through-holes 6 that are electroplated after being opened. These copper through-holes 6 provide electrical and heat dissipation pathways between different layers, adapting to the usage requirements of different power levels.

[0037] In one embodiment, the preparation method of the power chip embedded in the PCB power module in the above embodiment includes the following steps: preparing a molding compound 2 with an exposed lower copper layer 213 on its lower surface; embedding the molding compound 2 into the embedding hole 11 of the core board 1, with the lower surface of the lower copper layer 213 exposed in the embedding hole 11; preparing the upper structure of the core board 1 to obtain a PCB motherboard; cutting the PCB motherboard and removing the core board 1 outside the molding compound 2 to obtain the final product.

[0038] Specifically, the molding compound 2 with the exposed lower copper layer 213 on its lower surface includes: See Figure 4 The ceramic copper-clad substrate 21 is prepared with a lower copper layer 213 having a thickness greater than that of the upper copper layer 211; optionally, the upper copper layer 211 has a thickness of 0.3 mm, the ceramic copper-clad substrate 21 is made of Si3N4 material with a thickness of 0.32 mm, and the lower copper layer 213 has a thickness of 0.4 mm. Then, the area of ​​the copper layer 211 where the chip 23 and / or copper sheet 24 need to be sintered is treated with a silver plating layer 25. If a soldering process is used, no additional treatment is required. The area of ​​the silver plating area needs to be larger than the area of ​​the chip 23 and / or copper sheet 24. See Figure 5The copper sheet 24 can be sintered or welded at the corresponding position as needed; in some embodiments, the thickness of the copper sheet 24 + silver plating layer 25 can be slightly greater than the thickness of the chip 23 + silver plating layer 25, for example, the thickness of the copper sheet 24 + silver plating layer 25 is 0.25mm. See Figure 6 The ceramic copper-clad substrate 21 is encapsulated by molding compound 22, which covers the periphery and top of the ceramic copper-clad substrate 21, exposing the lower surface of the lower copper layer 213. The welding or sintering position of the upper copper layer 211 chip 23 is also exposed, forming a chip groove 231 with a size larger than that of the chip 23. For example, the gap between the chip groove 231 and the chip 23 is 150um. See Figure 7 Remove the molding compound 22 from the surface of the copper sheet 24 to expose it; this can be done by grinding, CNC machining, or other feasible processing methods to remove a portion of the thickness; after cleaning, weld / sinter the chip 23 onto the ceramic copper-clad substrate 21, ensuring that the height of the upper surface of the molding compound 22 is slightly greater than the height of the upper surface of the chip 23, for example, 10-50um higher.

[0039] Furthermore, participate Figure 8 Prepare a core board 1 with an embedded hole 11. The size of the hole is slightly larger than the size of the molding compound 2. The core board 1 and the molding compound 2 have the same thickness. Embed the molding compound 2 into the core board 1, and expose the lower surface of the copper overlay layer 213 through the embedded hole 11.

[0040] Furthermore, the preparation of the upper structure of the core board 1 includes: See Figure 9 and Figure 10 The prepreg layer 3 and the PCB copper layer 4 are pressed onto the core board 1; holes are drilled at appropriate locations using lasers and then electroplated to fill them, forming copper through holes 6 for electrical connections; the pressed PCB copper layer 4 is divided into multiple pieces according to functional requirements; the above steps can be performed once or repeatedly as needed (forming multiple layers of prepreg layer 3 and PCB copper layer 4); during the pressing process, epoxy resin is filled into the gaps between the chip groove 231, the core board 21, and the molding compound 2; See Figure 11 Then, apply solder resist layer 5 to cover the parts that need to be electrically connected to the outside, leaving the windows for soldering terminals or other components.

[0041] See Figure 12 Finally, the PCB motherboard is cut into sections using CNC machining or other methods, and the core board outside the molding compound is removed to obtain the final product.

[0042] In summary, the power chip embedded PCB power module of the present invention, through the structural design of pre-encapsulating the ceramic copper-clad substrate into a molded body and then embedding it into the core board embedding hole, reduces the amount of epoxy resin filling, lowers the process difficulty of PCB processing, and reduces the generation of defects such as voids and incomplete filling. Furthermore, by using the exposed lower copper layer as a heat dissipation surface, it significantly reduces the overall thermal resistance of the module and improves heat dissipation efficiency. At the same time, it reduces the cyclic thermal stress caused by the mismatch of thermal expansion coefficients between the PCB material and the ceramic copper-clad substrate, reduces the risk of insulation failure caused by ceramic layer cracking, and effectively improves the reliability and service life of the product. It is suitable for various high-power module manufacturing scenarios.

[0043] It should be noted that all the devices (parts whose specific structures are not specified) selected in this application are general standard parts or parts known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods.

[0044] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A power chip embedded in a PCB power module, characterized in that, include: The core board (1) has an embedded hole (11) that runs through the upper and lower surfaces. A molding compound (2) is disposed in the embedding hole (11); the molding compound (2) includes a ceramic copper-clad substrate (21) and molding compound (22) disposed on the periphery and the top side of the ceramic copper-clad substrate (21); the lower surface of the lower copper layer (213) of the ceramic copper-clad substrate (21) is exposed in the embedding hole (11). Several layers of prepreg (3) and PCB copper layer (4) are alternately disposed on the upper end of the core board (1); and Solder mask layer (5) located on the upper side of the top copper layer (4) of the PCB.

2. The power chip embedded PCB power module according to claim 1, characterized in that, The ceramic copper-clad substrate (21) includes an upper copper layer (211), a ceramic layer (212) and a lower copper layer (213) arranged sequentially from top to bottom. The thickness of the lower copper layer (213) is greater than that of the upper copper layer (211).

3. The power chip embedded PCB power module according to claim 2, characterized in that, The thickness of the lower copper cladding layer (213) is 10%-50% greater than the thickness of the upper copper cladding layer (211).

4. The power chip embedded PCB power module according to claim 2, characterized in that, Several regions on the upper surface of the copper overlay (211) are connected to chips (23).

5. The power chip embedded PCB power module according to claim 4, characterized in that, The upper surface of the copper overlay (211) has a plurality of chip slots (231) on the molding compound (22). The chip (23) is located in the chip groove (231), the edge gap between the chip (23) and the chip groove (231) is between 75-250um, and the height of the upper surface of the chip (23) is 10-50um lower than the height of the upper surface of the molding compound (22).

6. The power chip embedded PCB power module according to claim 4, characterized in that, Several areas on the upper surface of the copper overlay (211) are connected to copper sheets (24).

7. The power chip embedded PCB power module according to claim 6, characterized in that, The PCB copper layers (4) are connected to each other, between the PCB copper layers (4) and the chip (23), and between the PCB copper layers (4) and the copper sheet (24) through copper through holes (6).

8. A method for fabricating a power chip embedded in a PCB power module as described in any one of claims 1-7, characterized in that, include: Prepare a molding compound (2) with an exposed copper overlay (213) on the lower surface; The molding compound (2) is embedded in the embedding hole (11) of the core board (1), and the lower surface of the copper overlay (213) is exposed in the embedding hole (11). The core board (1) is prepared to obtain the PCB motherboard; The PCB motherboard is cut apart, and the core board (1) on the outside of the plastic encapsulation (2) is removed to obtain the final product.

9. The preparation method according to claim 8, characterized in that, The molding compound (2) for preparing the exposed lower copper cladding layer (213) includes: Prepare a ceramic copper-clad substrate (21) with a thickness greater than that of the upper copper layer (211). Then, the areas of the copper overlay (211) where the chip (23) and / or copper sheet (24) need to be sintered are treated with a silver plating layer (25). If a soldering process is used, no additional treatment is required. Copper sheets (24) are sintered or welded at the corresponding positions as needed. The ceramic copper-clad substrate (21) is encapsulated by encapsulating material (22) around the periphery and top of the ceramic copper-clad substrate (21), exposing the lower surface of the lower copper layer (213), and the soldering or sintering position of the upper copper layer (211) chip (23) is also exposed, forming a groove larger than the chip (23). Grind away a portion of the thickness from the upper surface of the encapsulated body (2) to remove the encapsulating material (22) from the surface of the copper sheet (24) and expose it; The chip (23) is soldered or sintered to the overlying copper layer (211).

10. The preparation method according to claim 7, characterized in that, The upper structure of the core board (1) includes: The prepreg layer (3) and the PCB copper layer (4) are pressed onto the core board (1); A copper through hole for electrical connection is formed by laser drilling and electroplating filling at the appropriate location. (6) The laminated PCB copper layer (4) is divided into multiple pieces according to functional requirements; The above steps may be performed once or repeated multiple times as needed; during the pressing process, epoxy resin fills the gap between the core plate (21) and the molding compound (2); Then apply a solder resist layer (5) to cover the parts that need to be electrically connected to the outside, leaving the windows for soldering terminals or other components.

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