Manufacturing method of multilayer thermoelectric separation buried copper plate

Abstract

The invention discloses a manufacturing method of a multi-layer thermoelectric separation buried copper plate, which comprises the steps of preparing an inner-layer core plate, slotting and burying a copper block, roughly drilling a through hole, filling resin, manufacturing a secondary outer-layer pattern, preparing an outer-layer core plate, drilling a conductive hole and a heat dissipation hole and the like, and is characterized in that the copper block is divided into a heat dissipation area and a conductive area; thermoelectric separation is achieved through the design of independent through holes and blind holes, components needing to conduct electricity and components needing to conduct heat can be added on the copper block at the same time, and meanwhile efficient heat conduction and stable signal transmission are achieved and do not interfere with each other. Due to the partition design, the copper block is not only used for heat dissipation, but also used for electric conduction, the utilization rate of the copper block is improved, the design area of the PCB is reduced, and the development requirements of high-density and miniaturized electronic equipment are met.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit board manufacturing, in particular to a method for manufacturing a multi-layer thermoelectric separation buried copper plate. Background Art

[0002] With the rapid development of technologies such as 5G communications, artificial intelligence, new energy vehicles, LED lighting, and wearable devices, electronic devices are rapidly developing towards high integration and miniaturization. Such devices require printed circuit boards to carry more components in a limited space and meet the dual needs of high-speed signal transmission and efficient heat dissipation. In traditional printed circuit board design, heat dissipation modules and conductive lines are often laid out independently, and embedded copper blocks are usually only used as single-function carriers. When used only for heat dissipation, copper blocks cannot take into account the conductive needs, and additional conductive lines need to be designed, increasing the number of PCB layers and complexity; when used only for conduction, the heat dissipation capacity is insufficient, especially for power devices (such as power modules and RF chips), heat accumulation can easily lead to local overheating and affect signal stability; and the thermoelectric path in the traditional design is not effectively separated, which will also cause thermoelectric coupling interference, such as temperature changes affecting conductive properties, or current loss exacerbating heat generation, making it difficult to achieve coordinated optimization of heat dissipation and conductivity in high-density scenarios. This heat dissipation and conductive separation design often leads to low copper resource utilization and redundant printed circuit board area, making it difficult to adapt to the development trend of miniaturization and multi-function. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for manufacturing a multi-layer thermoelectric separation buried copper plate, comprising the following steps: Preparation of inner core board: Cut the insulating substrate into target size according to design requirements, and laminate the surface of the insulating substrate with the first copper foil to obtain the copper clad laminate. Then, set the cursor point at the gong position of the copper clad laminate, and use laser to drill foolproof holes to obtain the inner core board. Grooving and embedding copper blocks: according to the size of the copper block, grooves are made at the designated position of the inner core board. The groove depth is slightly greater than the thickness of the copper block. After the copper block is embedded in the groove, the first prepreg is pasted, the edge is aligned with the cursor point, and pressed at one time to form the second outer core board; Rough drilling of through holes: Drilling the initial through hole on the copper block and pre-enlarging the hole diameter. The initial through hole penetrates the copper block; Filling resin: injecting resin into the pre-enlarged initial through hole and heating to cure; Making the sub-outer pattern: coating the surface of the sub-outer core board with dry film, etching the first copper foil after exposure and development to form the sub-outer conductive circuit, the distance between the sub-outer conductive circuit and the edge of the copper block is ≥0.5mm; Preparation of outer core board: Lay the second prepreg and the second copper foil on the surface of the second outer core board, align the edges with the cursor points, and perform secondary lamination to obtain the outer core board; Drilling conductive holes and heat dissipation holes: Drill blind holes on one side of the outer core board, control the depth to penetrate to the surface of the copper block to form a thermal conductive hole, and drill conductive holes on the resin-filled area at the same time, fill the thermal conductive holes with copper, plate the inner wall of the conductive holes with copper, and then brown or gold-plate the surface of the outer core board to obtain the finished product.

[0004] Preferably, the initial through hole diameter is 0.2-0.3 mm.

[0005] Preferably, the pre-enlarged aperture is 0.3-0.7 mm.

[0006] Preferably, the resin is polypropylene resin or epoxy resin.

[0007] Preferably, the conductive hole diameter is 0.1-0.2 mm.

[0008] Preferably, the blind hole diameter is 0.5-1 mm.

[0009] Preferably, the curing is completed by heating the temperature to 150-160° C. at a heating rate of 2-4° C. / min and keeping the temperature for 40-60 min.

[0010] Preferably, the insulating substrate is prepared by using epoxy glass fiber cloth substrate FR-4 or composite epoxy resin glass fiber cloth substrate CEM-3.

[0011] Preferably, the pressure during the first pressing and the second pressing is 7 to 9 tons / m 2 The temperature is 130~170℃ and the duration is 30~60min.

[0012] Preferably, the thickness of the first copper foil and the second copper foil is 18-35 μm.

[0013] The beneficial effects of the present application are as follows: the copper block is divided into a heat dissipation area and a conductive area, and thermal and electrical separation is achieved through independent through-hole and blind-hole designs. Components that require electrical conduction and components that require thermal conduction can be added to the copper block at the same time, and efficient heat conduction and stable signal transmission are achieved without interfering with each other. This partition design allows the copper block to be used not only for heat dissipation but also for electrical conduction, thereby improving the utilization rate of the copper block and reducing the PCB design area to meet the development needs of high-density and miniaturized electronic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 This is a schematic diagram of the structure of a multi-layer thermoelectric separation buried copper plate; In the figure: 1. Inner core board; 2. Copper block; 3. Initial through hole; 31. Conductive hole; 4. Thermal holes. DETAILED DESCRIPTION

[0015] The following will disclose multiple embodiments of the present invention with drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary. In addition, for the purpose of simplifying the drawings, some conventional structures and components will be depicted in a simple schematic manner in the drawings.

[0016] In addition, in the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0017] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0018] The following embodiments are only used to illustrate the present invention, but are not limited to the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the protection scope of the present invention.

[0019] In the examples of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the examples of the present invention, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art.

[0020] Source of raw materials: Epoxy glass fiber cloth substrate FR-4, purchased from Dongguan Xingteng Plastic Products Co., Ltd.; Composite epoxy resin glass fiber cloth substrate CEM-3, purchased from Shanghai Weifen Industrial Co., Ltd.; Two-component epoxy glue AB glue, Jiudian brand JD-8112, purchased from Han Gaoda Trading (Shenzhen) Co., Ltd.; Polyurethane glue, Lancolu L-8460, was purchased from Guangdong Canqi New Materials Co., Ltd.; Acrylic glue, Humiseal UV40, was purchased from Shenzhen Shiyun Materials Co., Ltd.; Polypropylene resin, S2040, was purchased from Shanghai QiaoWei Chemical Technology Co., Ltd.; Epoxy resin, ER2188, was purchased from Dongguan Bei - Electronic Materials Co., Ltd.; All other reagents were commercially available as normal.

[0021] Example Please refer to Figure 1 , Figure 1 , which is a schematic diagram of a multi - layer thermoelectric separation buried copper plate structure; This example provides a multi - layer thermoelectric separation buried copper plate, including an inner core board with an installation groove, a copper block is embedded in the installation groove, a through - initial through - hole is opened in the conductive area of the copper block, resin is injected into the initial through - hole, a through - conductive hole is provided on the resin, a heat - conducting hole is provided in the heat - dissipation area of the copper block, and the heat - conducting hole is filled with copper material.

[0022] The manufacturing method of the above - mentioned multi - layer thermoelectric separation buried copper plate includes the following steps: Preparing the inner core board: Cut an insulating substrate with a thickness of 2 - 3 mm into a target size according to design requirements, and laminate a first copper foil with a thickness of 18 - 35 μm on the surface of the insulating substrate to obtain a copper - clad laminate. Then, set light points at the routing positions of the copper - clad laminate, and at the same time, use a laser drill to set anti - misalignment holes. Then, through deburring, degreasing, electroplating, and etching, the inner core board is obtained; The insulating substrate is prepared from epoxy glass fiber cloth substrate FR - 4 or composite epoxy resin glass fiber cloth substrate CEM - 3; The setting of the laser - drilled anti - misalignment holes and light points can achieve high - precision alignment, ensuring the hole - position accuracy of the copper - block embedding position, conductive holes, and heat - conducting holes, and avoiding the failure of the thermoelectric channel caused by offset; Grooving and embedding the copper block: According to the size of the copper block, use a CNC milling machine or laser cutting to groove at a specified position on the inner core board. The groove depth is slightly greater than the thickness of the copper block. In this example, the groove depth is 1.3 - 1.5 mm, the copper - block thickness is 0.8 - 1.1 mm, the epoxy adhesive coating thickness is 10 - 15 μm. After the copper block is embedded in the groove, laminate the first semi - cured sheet, align the edges with the light points, and perform a one - time lamination. The pressure during lamination is 7 - 9 tons / m 2 , the temperature is 130 - 170 °C, and the duration is 30 - 60 min to form a sub - outer core board; The epoxy adhesive can be any one of two - component epoxy glue, polyurethane glue, and acrylic glue. The epoxy adhesive can firmly bond the copper block in the groove; By grooving at a specified position on the inner core board and embedding the copper block, using the high thermal conductivity of copper, the heat generated when the electronic component works can be quickly conducted to the copper block, and then the heat is diffused to the entire board through the copper block, thereby achieving efficient heat conduction and reducing the temperature of the electronic component; Rough - drilling through - holes: Use a CNC drill to drill initial through - holes on the copper block and pre - enlarge the hole diameter. The initial through - hole diameter is 0.2 - 0.3 mm, the pre - enlarged hole diameter is 0.3 - 0.7 mm, and the initial through - hole penetrates the copper block; Filling resin: Use a pressure pump to inject resin into the initially enlarged through-holes, and heat and cure at a heating rate of 2 - 4 °C / min to 150 - 160 °C for 40 - 60 min. Either polypropylene resin or epoxy resin can be selected as the resin. After filling the resin, an insulating support is formed to prevent the copper block from directly conducting electricity, providing conditions for the functional separation of subsequent conductive holes and heat-conducting holes. At the same time, the heat conduction path becomes more clear and efficient, preventing the disordered diffusion of heat through the conductive path and further improving the heat conduction efficiency. Manufacturing the sub-outer layer pattern: Coat a dry film on the surface of the sub-outer layer core board. After exposure and development, etch the first copper foil to form the sub-outer layer conductive circuit. The distance between the sub-outer layer conductive circuit and the edge of the copper block is ≥ 0.5 mm to avoid the erosion of the copper block edge by the etching solution, ensuring the integrity and stability of the sub-outer layer conductive circuit, providing a reliable path for signal transmission, and preventing short circuits. Preparing the outer layer core board: Bond a second semi-cured sheet and a second copper foil with a thickness of 18 - 35 μm on the surface of the sub-outer layer core board, aligning the edges with the light marks, and performing secondary lamination. The pressure during lamination is 7 - 9 tons / m 2 , the temperature is 130 - 170 °C, and the duration is 30 - 60 min to obtain the outer layer core board. The two-step lamination process is adopted to ensure the tight bonding between the copper block, the insulating substrate, and the semi-cured sheet, reducing the interlayer voids and contact resistance, and at the same time reducing the thermal interface thermal resistance. Drilling conductive holes and heat dissipation holes: Use a laser drill or a depth-controlled drill to drill blind holes with a diameter of 0.5 - 1 mm on one side of the outer layer core board, and control the depth to penetrate to the surface of the copper block to form heat dissipation holes. At the same time, use a numerical control drill to drill conductive holes with a diameter of 0.1 - 0.2 mm in the resin filling area, and fill the heat dissipation holes with copper material. The resin filling layer forms a thermal insulation barrier to avoid lateral heat crosstalk and block the direct conduction between the copper block and the conductive holes. Filling the heat dissipation holes with copper material realizes a dot matrix heat dissipation structure, providing a direct and efficient conduction channel for heat, enabling heat to be transferred from the heating element to the copper block more quickly, and then diffusing out through the copper block, effectively reducing the thermal resistance, improving the heat dissipation efficiency, and enhancing heat conduction. Electroplating copper on the inner wall of the conductive holes realizes electrical connection, and then browning or gold plating the surface of the outer layer core board to obtain the finished product. The distribution density of the conductive holes and the heat dissipation holes can be independently designed, and the wiring is more flexible.

[0023] The above is only the implementation mode of the present invention and is not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A method for manufacturing a multi-layer thermoelectric separation buried copper plate, characterized in that: The following steps are involved: Preparation of inner core board: cutting the insulating substrate into target size according to design requirements, and laminating the surface of the insulating substrate with a first copper foil to obtain a copper clad laminate, and then setting a cursor point at the gong position of the copper clad laminate, and using a laser to drill foolproof holes to obtain the inner core board; Grooving and embedding copper blocks: according to the size of the copper blocks, grooves are made at the designated positions of the inner core board, the groove depth is slightly greater than the thickness of the copper blocks, and after the copper blocks are embedded in the grooves, the first prepreg is applied, the edges are aligned with the cursor points, and the plates are pressed at one time to form the secondary outer core board; Rough drilling of through holes: drilling an initial through hole on the copper block and pre-enlarging the hole diameter, wherein the initial through hole passes through the copper block; Filling resin: injecting resin into the pre-enlarged initial through hole and heating and curing; Making the sub-outer pattern: coating a dry film on the surface of the sub-outer core board, etching the first copper foil after exposure and development, to form a sub-outer conductive circuit, wherein the distance between the sub-outer conductive circuit and the edge of the copper block is ≥0.5 mm; Prepare the outer core board: paste the second prepreg and the second copper foil on the surface of the secondary outer core board, align the edges with the cursor points, and perform secondary lamination to obtain the outer core board; Drilling conductive holes and heat dissipation holes: Drill blind holes on one side of the outer core board, control the depth to penetrate to the surface of the copper block to form a thermal conductive hole, and drill conductive holes on the resin-filled area at the same time, fill the thermal conductive holes with copper, plate the inner wall of the conductive holes with copper, and then brown or gold-plate the surface of the outer core board to obtain the finished product.

2. The method for manufacturing a multi-layer thermoelectric separation buried copper plate according to claim 1, characterized in that: The initial through hole diameter is 0.2-0.3 mm.

3. The method for manufacturing a multi-layer thermoelectric separation buried copper plate according to claim 1, characterized in that: The pre-enlarged aperture is 0.3-0.7 mm.

4. The method for manufacturing a multi-layer thermoelectric separation buried copper plate according to claim 1, characterized in that: The resin is polypropylene resin or epoxy resin.

5. The method for manufacturing a multi-layer thermoelectric separation buried copper plate according to claim 1, characterized in that: The conductive hole has a diameter of 0.1-0.2 mm.

6. The method for manufacturing a multi-layered thermoelectric separation buried copper plate according to claim 1, characterized in that: The blind hole has a diameter of 0.5-1 mm.

7. The method for manufacturing a multi-layer thermoelectric separation buried copper plate according to claim 1, characterized in that: The heating curing method is completed by heating the temperature to 150-160° C. at a heating rate of 2-4° C. / min and keeping the temperature for 40-60 minutes.

8. The method for manufacturing a multi-layer thermoelectric separation buried copper plate according to claim 1, characterized in that: The insulating substrate is prepared by using an epoxy glass fiber cloth substrate FR-4 or a composite epoxy resin glass fiber cloth substrate CEM-3.

9. The method for manufacturing a multi-layered thermoelectric separation buried copper plate according to claim 1, characterized in that: The pressure during the first pressing and the second pressing is 7-9 tons / m 2 The temperature is 130~170℃ and the duration is 30~60min.

10. The method for manufacturing a multi-layered thermoelectric separation buried copper plate according to claim 1, characterized in that: The thickness of the first copper foil and the second copper foil is 18-35 μm.

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