Embedded copper block circuit board and manufacturing method thereof

Abstract

The invention discloses a copper block embedded circuit board and a manufacturing method thereof, and the manufacturing method comprises the steps: two outer layers of a core board are copper foil layers, and a non-circuit region of one outer layer is provided with a windowing position A; performing double-sided inner layer pattern manufacturing on the core board so as to respectively manufacture an inner layer circuit pattern and a bonding pad on two outer layers of the core board, and manufacturing a plurality of flow choking blocks surrounding the windowing position A on one outer layer of the core board; insulating layers cover the two outer layers of the core plate, and a windowing position B opposite to the windowing position A is arranged on the insulating layer adjacent to the flow choking block; windowing the insulating layer and the core plate based on the windowing position to obtain a window; and after copper blocks with rough surfaces are placed in the window in a clearance manner, pressing treatment is carried out, and flow blocking control is carried out on colloid flow in the window by virtue of a flow blocking block in the pressing process, so that the copper blocks, the insulating layer and the core plate are firmly combined together. The manufacturing method is simple, reasonable and easy to implement, the reliability and the stability of the obtained circuit board product are high, and market requirements are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board processing, in particular to a buried copper block circuit board and a manufacturing method thereof. BACKGROUND

[0002] With the rapid development of new energy industry, PCB boards are more and more widely used in high-power electronic products such as motor controller boards, inverters, power modules, etc. At the same time, due to the characteristics of concentrated heat dissipation and large current carrying of LED light sources, integrated blocks, capacitors and other high-power components in the working process, higher requirements are put forward for the heat dissipation, electrical conductivity, material mechanical strength, thermal stress and other performances of the PCB board surface.

[0003] In order to improve the heat dissipation performance of the PCB board, the conventional method in the PCB industry is to set a groove on the PCB board, and then put a large copper block (or ceramic body) into the groove and perform a pressing process to combine the large copper block (or ceramic body) with the PCB board. However, due to the poor bonding force between the copper block (or ceramic) and the insulating layer (such as prepreg) on the PCB board, and the inconsistent thermal conductivity coefficient, it is easy to cause the copper surface (or ceramic surface) to be concentratedly heated during subsequent high-temperature processes such as tin spraying, which leads to the occurrence of adverse phenomena such as board explosion and layer separation of the insulating layer around the copper block (or ceramic), seriously affecting the yield of the finished PCB board.

[0004] In order to overcome the above technical problems, many technical improvements have been made in the industry, such as increasing the number of prepregs or using high-gel-content prepregs to improve the bonding strength between the prepreg and the copper block (or ceramic). However, the improvement effect is general, and it is difficult to fundamentally solve the problem, and the cost is high. Therefore, the present application is proposed. SUMMARY

[0005] In order to overcome the above defects, the present application provides a buried copper block circuit board and a manufacturing method thereof. The manufacturing method is simple, reasonable, easy to operate and implement, and the reliability and stability of the obtained circuit board product are very high, which well meets the market demand of high-power electronic products.

[0006] The technical scheme adopted by the present application to solve the technical problems is as follows: a manufacturing method of a buried copper block circuit board, comprising the following manufacturing steps: S1: providing a copper block and a core board, the surface of the copper block being rough, the two outer layers of the core board being copper foil layers, and a window position A being provided on a non-wiring area of one of the outer layers of the core board, the window position A being a position that needs to be windowed in subsequent processing; S2: performing double-sided inner layer patterning on the core board, so as to respectively produce inner layer circuit patterns and pads on the two outer layers of the core board, and further producing a plurality of flow blocking blocks arranged outside the window position A on one outer layer of the core board; S3: Covering the two outer layers of the core plate with insulating layers respectively, and providing a window position B corresponding to the window position A on one of the insulating layers adjacent to the baffle block; S4: Opening windows on the insulation layer and the core board based on the window opening position B and the window opening position A to obtain windows; S5: placing the copper block gap in the window and performing a pressing process. During the pressing process, the flow of the colloid in the window is controlled by the flow blocking block, so that the copper block is firmly combined with the insulation layer and the core board.

[0007] As a further improvement of the present invention, a convex structure and / or a concave structure is provided on the peripheral side surface of the copper block, and the shape of the window matches the shape of the copper block to achieve a snap connection between the two; In addition, after the copper block is placed in the window, a gap of 0.025 mm to 0.05 mm is formed between the peripheral side surface of the copper block and the inner side wall of the window.

[0008] As a further improvement of the present invention, chamfers with a radius of 0.5 mm to 2 mm are respectively processed at the four corners of the copper block.

[0009] As a further improvement of the present invention, the surface of the copper block is roughened by sandblasting, wire drawing or browning, and the surface roughness of the copper block is controlled to be Ra≥0.15μm and Rz≥1.5μm.

[0010] As a further improvement of the present invention, in the above S2, the double-sided inner layer pattern is produced by a subtractive process or an mSAP process; wherein the subtractive process includes the following steps: pre-coating treatment, coating with a resist photosensitive film, exposure, development, etching, and film stripping; and the mSAP process includes the following steps: pre-coating treatment, coating with a resist photosensitive film, exposure, development, pattern electroplating, film stripping, baking, and flash etching. In addition, after the above S2 is completed, the window position A is a copper-free area.

[0011] As a further improvement of the present invention, the line width and line spacing of the exposure material are 4 mils respectively, and the exposure energy is 200-250 MJ / cm 2 ;Development speed is 3~3.3m / min; The line width of the inner layer circuit pattern is 5-10 μm, and the line spacing is 5-10 μm; the copper thickness of the inner layer circuit pattern, the pad and the blocking block are 30-35 μm respectively.

[0012] As a further improvement of the present invention, in the above S3, the insulating layer is fixedly arranged on the outer layer of the core board through a lamination process, and the insulating layer adopts a prepreg or pure glue.

[0013] As a further improvement of the present invention, in the above S4, a UV picosecond laser is used to open windows in the insulating layer and the core board, and the processing parameters of the UV picosecond laser are: output power of 1000~3000W, repetition frequency of 100~250Hz, laser scanning speed of 50~100mm / s, and number of scans of 1~2 times.

[0014] As a further improvement of the present invention, in the pressing process of S5, the pressing temperature is controlled as follows: in a time sequence, the holding times at temperatures of 140°C, 155°C, 165°C, 180°C, 195°C, 210°C, 180°C and 140°C are 29 min, 4 min, 0 min, 0 min, 5 min, 75 min, 5 min and 10 min respectively; and in the control of the pressing temperature, the temperature is raised from 140°C to The heating time from 155°C to 165°C is 6 minutes, the heating time from 155°C to 165°C is 5 minutes, the heating time from 165°C to 180°C is 3 minutes, the heating time from 180°C to 195°C is 5 minutes, the heating time from 195°C to 210°C is 5 minutes, the cooling time from 210°C to 185°C is 5 minutes, and the cooling time from 185°C to 140°C is 10 minutes; The pressing pressure is controlled as follows: according to the timing, at a pressure of 70PSI / cm 2 , 150PSI / cm 2 , 200PSI / cm 2 、300PSI / cm 2 、350PSI / cm 2 , 360PSI / cm 2 , 200PSI / cm 2 and 150PSI / cm 2 The holding time under the pressure is 0min, 15min, 10min, 5min, 3min, 90min, 5min and 15min respectively; and in the control of the pressing pressure, the pressure is 70PSI / cm 2 Boost pressure to 150PSI / cm 2 The pressure rise time is 2 minutes, from 150PSI / cm 2Boost pressure to 200PSI / cm 2 The pressure rise time is 2 minutes, from 200PSI / cm 2 Boost pressure to 300PSI / cm 2 The pressure rise time is 5 minutes, from 300PSI / cm 2 Boost pressure to 350PSI / cm 2 The pressure rise time is 2 minutes, from 350PSI / cm 2 Boost pressure to 360PSI / cm 2 The pressure rise time is 3 minutes, from 360PSI / cm 2 Reduce blood pressure to 200 PSI / cm 2 The decompression time is 5 minutes, from 200PSI / cm 2 Reduce blood pressure to 150 PSI / cm 2 The decompression time is 5 minutes.

[0015] The present invention also provides a buried copper block circuit board, which is manufactured using the method for manufacturing the buried copper block circuit board of the present invention.

[0016] The beneficial effects of the present invention are as follows: ① The present invention innovatively arranges a plurality of flow-blocking blocks around the window, and then improves and optimizes the combination method of the copper block and the window, the pressing treatment method, etc., which can effectively improve the filling capacity of the colloid and achieve a more substantial colloid filling, thereby effectively reducing defects such as voids and delamination caused by uneven colloid flow, thereby significantly improving the bonding strength between the copper block and the surrounding substrate, and significantly improving the reliability and stability of the circuit board product. ② The method for making the buried copper block circuit board of the present invention is simple, reasonable, novel, easy to produce and implement, and the quality of the resulting buried copper block circuit board is good, which can well meet the market demand for high-power electronic products. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a process flow chart of the method for manufacturing the buried copper block circuit board described in Example 1 of the present invention; Figure 2 This is one of the schematic cross-sectional views of the copper block described in Example 1; Figure 3 This is a second schematic diagram of the cross-sectional structure of the copper block described in Example 1; Figure 4 Schematic diagram of the cross-sectional structure of the core plate described in Example 1; Figure 5 Schematic diagram of the cross-sectional structure of the board A obtained after the double-sided inner layer patterning is completed on the core board in Example 1; Figure 6Schematic diagram of the cross-sectional structure of board B obtained after insulating layers are applied to both sides of board A obtained in Example 1; Figure 7 Schematic diagram of the cross-sectional structure of board C obtained after windowing operation is performed on board B obtained in Example 1; Figure 8 for Figure 7 Schematic diagram of the cross-sectional structure of the window shown in another perspective; Figure 9 Schematic diagram of the cross-sectional structure of the intermediate plate obtained in Example 1.

[0018] The following description is made with reference to the accompanying drawings: 1. Copper block; 10. Main body; 11. Convex structure; 2. Core board; 20. Current blocking block; 21. Insulating middle layer; 22. Copper foil layer; 23. Inner circuit pattern; 3. Insulating layer; 4. Window; 40. Concave structure. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0020] Example 1

[0021] Please see the attached Figure 1 As shown, this embodiment 1 provides a method for manufacturing a copper-embedded circuit board, including the following manufacturing steps: S1: Provide copper block 1 and core board 2.

[0022] In this embodiment 1, the surface of the copper block 1 is preferably designed to be a rough surface to enhance the bonding strength between the copper block 1 and other components / materials such as the core board 2 in subsequent manufacturing processes.

[0023] Furthermore, in this embodiment 1, the surface of the copper block 1 is roughened by a sandblasting process, a wire drawing process or a browning process, and the surface roughness of the copper block 1 is optimally controlled to be Ra≥0.15μm and Rz≥1.5μm, so as to achieve the best bonding performance of the copper block 1.

[0024] In addition, in order to further improve the bonding quality between the copper block 1 and the core plate 2 and other components / materials, this embodiment 1 also specifically improves the structure of the copper block 1, specifically: Figure 2 and attached Figure 3As shown, the copper block 1 is provided with a block-shaped main body 10 and an outer convex structure 11 integrally provided on the side surface of the main body 10, wherein the four corners of the main body 10 are respectively processed with arc chamfers with a radius of 0.5mm to 2mm, so as to ensure the flatness and fit of the copper block 1 when it is placed in the window 4 in the later process; the outer convex structure 11 is used to snap-connect with the window 4 in the later process to ensure that the copper block 1 will not deviate during the pressing process of the later process, ensuring that the copper block 1 and the window 4 are stably and firmly connected. As for the specific shape of the outer convex structure 11, it can be adopted but not limited to a wave shape (see attached Figure 3 shown) or dovetail (see attached Figure 2 shown).

[0025] Supplementary Notes: ① The size and shape of the circular chamfers at the four corners of the main body 10 can be consistent or inconsistent, depending on the specific design requirements of the circuit board product, and are not limited in this embodiment 1. ② In addition to providing the convex structure 11 on the copper block 1, the convex structure 11 can also be replaced with a concave structure, or a combination of a convex structure and a concave structure can be provided on the copper block 1; it is understood that as long as the copper block 1 can be connected to the window 4 by a snap fit, it will be sufficient.

[0026] In this embodiment 1, both outer layers of the core board 2 are copper foil layers, and a window position A is provided on the non-circuit area of ​​one of the outer layers of the core board 2. The window position A is the position where a window needs to be opened in subsequent processing.

[0027] It is understandable that the core board 2 can be made of various types of work boards according to the processing requirements of the circuit board product. However, in order to facilitate the description of the manufacturing method of the buried copper block circuit board described in this application, this embodiment 1 takes the core board 2 as an example of a double-sided copper clad board. That is, the structure of the core board 2 is as follows: Figure 4 As shown, the core board 2 is provided with an insulating intermediate layer 21 and two copper foil layers 22 fixedly covered on opposite sides of the insulating intermediate layer 21. The insulating intermediate layer 21 can preferably be made of glass fiber cloth reinforced epoxy resin (FR-4), polyimide (PI) or polytetrafluoroethylene (PTFE), etc., and the window position A is provided on the non-circuit area of ​​one of the copper foil layers 22.

[0028] S2: Double-sided inner layer patterning is performed on the core board 2 to respectively produce inner layer circuit patterns and pads on the two outer layers of the core board 2, and a plurality of flow blocking blocks 20 arranged outside the window position A are also produced on one outer layer of the core board 2; then board A is obtained.

[0029] Specifically, in this embodiment 1, a subtractive process is used to produce double-sided inner layer patterns on the core board 2. The specific production method is as follows: ① Pre-laminar treatment: The two copper foil layers 22 of the core board 2 are sequentially roughened, cleaned, and dried to enhance the bonding strength between the anti-corrosion photosensitive dry film and the copper foil layers 22 in subsequent processes. The roughening treatment may preferably be, but is not limited to, a ceramic grinding plate or micro-etching treatment.

[0030] ② Laminating the photosensitive film: Laminating the photosensitive dry film on the two copper foil layers 22 by a vacuum laminating machine. It is understandable that the vacuum laminating machine can achieve high-flatness laminating operation, which can effectively improve the bonding strength between the photosensitive dry film and the copper foil layer 22.

[0031] ③ Exposure and development: Use the LDI exposure machine to expose part of the area of ​​the resist photosensitive dry film according to the operating data, and then develop and remove the unexposed area of ​​the resist photosensitive dry film.

[0032] Furthermore, the specific processing conditions of the exposure and development operations are optimized as follows: the line width and line spacing of the exposure data are 4 mils respectively, and the exposure energy is 200-250 MJ / cm 2 ; The developing speed is 3~3.3m / min; to achieve better production of the inner layer graphics.

[0033] ④ Etching: using an alkaline etching solution to remove the portions of the two copper foil layers 22 that are not covered by the anti-corrosion photosensitive dry film.

[0034] ⑤ Stripping: Use a strong alkaline solution to completely remove the anti-corrosion photosensitive dry film on the core board 2. At that time, the inner layer pattern can be made on the two copper foil layers 22. For details, please refer to the attached Figure 5 shown.

[0035] It is understandable that, according to the design requirements of the circuit board product, inner layer circuit patterns 23 and solder pads are respectively produced on the two copper foil layers 22, and a plurality of flow blocking blocks 20 arranged outside the window position A are also produced on the non-circuit area of ​​the copper foil layer 22 where the window position A is provided. Supplementary explanation: ① After the above-mentioned inner layer pattern production is completed, the window position A can be presented as a copper-containing area or a copper-free area, but in order to facilitate and facilitate the windowing operation in the subsequent process, this embodiment 1 is preferably designed as follows: After the double-sided inner layer pattern production is completed (i.e., the above-mentioned S2), the window position A is presented as a copper-free area, i.e., a part of the insulating intermediate layer 21 is exposed. For details, please refer to the attached. Figure 5 ② Since the plurality of baffles 20 are arranged in the non-circuit area and spaced apart at predetermined intervals, they will not affect the electrical performance of the circuit board product.

[0036] Furthermore, according to the design requirements of the circuit board product and based on the above-mentioned double-sided inner layer pattern production method, in this embodiment 1, the technical parameters of the inner layer pattern obtained are: the line width of the inner layer circuit pattern 23 is 5 to 10 μm, and the line spacing is 5 to 10 μm; the copper thickness of the inner layer circuit pattern 23, the solder pad and the baffle block 20 are 30 to 35 μm respectively.

[0037] Furthermore, based on the copper thickness requirement of the obtained inner layer pattern, this embodiment 1 may further perform a whole-board electroplating process before performing the above-mentioned lamination pre-treatment process, so that the copper thickness meets the circuit board product requirements.

[0038] S3: Insulation layers 3 are respectively applied to the two outer layers of the core plate 2, and a window position B corresponding to the window position A is provided on one of the insulation layers 3 adjacent to the baffle block 20, and then a board B is obtained (see attached Figure 6 shown).

[0039] Specifically, after completing the above S2, the insulating layer 3 can be fixedly disposed on the two copper foil layers 22 of the core board 2 through a lamination process, and the insulating layer 3 can preferably be made of prepreg or pure glue. Further, in this embodiment 1, the insulating layer 3 is made of prepreg.

[0040] Note: ① The above lamination process is a conventional technical means in the field of circuit board processing, so it will not be described in detail here. ② Regarding the number and thickness of the insulating layer 3, this embodiment 1 does not impose any restrictions and is determined according to the specific processing requirements.

[0041] S4: Based on the window opening position B and the window opening position A, the insulating layer 3 and the core plate 2 are opened to obtain a window 4. Figure 7 As shown; and then you will get board C.

[0042] Specifically, since the window opening position B is set correspondingly to the window opening position A (it can also be understood as being set opposite to each other), this embodiment 1 can use a laser (preferably a UV picosecond laser) and perform window opening operations on the insulating layer 3 and the core board 2 based on the window opening position B and the window opening position A to obtain the window 4. Please continue to refer to the attached Figure 7 As shown, the window 4 can be understood as a blind groove structure with a portion of the insulating intermediate layer 21 serving as a groove body and opening on a surface of the insulating layer 3 facing away from the core plate 2 .

[0043] Furthermore, the processing parameters of the UV picosecond laser are: output power of 1000-3000 W, repetition frequency of 100-250 Hz, laser scanning speed of 50-100 mm / s, and number of scans of 1-2 times.

[0044] Furthermore, the shape of the window 4 matches the shape of the copper block 1, so that after the copper block 1 is placed in the window 4, the two can be snap-fitted together; specifically, when a convex structure 11 is provided on the peripheral side of the copper block 1, the window 4 is provided with a concave structure 40 that snaps into contact with the convex structure 11 (see the attached figure). Figure 8 As shown); when a concave structure A is provided on the peripheral side of the copper block 1, the window 4 is provided with a convex structure A that is snap-fitted with the concave structure A.

[0045] In addition, this embodiment 1 also optimizes the size of the window 4 and the copper block 1, which is manifested in that: after the copper block 1 is placed in the window 4, there is a gap of 0.025mm to 0.05mm between the peripheral side surface of the copper block 1 and the inner wall of the window 4; so as to achieve control of the appropriate filling amount.

[0046] S5: The copper block 1 is placed in the window 4 and then pressed together. During the pressing process, the flow block 20 is used to control the flow of the colloid in the window 4, so that the copper block 1 is firmly combined with the insulation layer 3 and the core plate 2. For details, please refer to the attached Figure 9 As shown. It can be understood that during the pressing process, the insulating layer 3 is heated and melted into a colloid, which is then filled into the gap between the copper block 1 and the window 4. The flow blocking block 20 can effectively prevent a large amount of colloid from overflowing while allowing a small amount of colloid to be squeezed outward after pressing into place, thereby achieving a more substantial filling of the colloid, reducing defects such as voids and delamination caused by uneven colloid flow, thereby improving the bonding strength between the copper block 1 and the surrounding substrate, and improving the reliability and stability of the circuit board.

[0047] In addition, this embodiment 1 also optimizes and controls the processing parameters of the above-mentioned pressing process (especially the pressing temperature and pressing pressure) to further improve the pressing quality. Specifically, in the above-mentioned pressing process, the pressing temperature is controlled as follows: in a time sequence, the holding times at 140°C, 155°C, 165°C, 180°C, 195°C, 210°C, 180°C and 140°C are 29 min, 4 min, 0 min, 0 min, 5 min, 75 min, 5 min and 10 min respectively; and in the control of the pressing temperature, the temperature is increased from 140°C to 155°C for 6 min, the temperature is increased from 155°C to 165°C for 5 min, the temperature is increased from 165°C to 180°C for 3 min, the temperature is increased from 180°C to 195°C for 5 min, the temperature is increased from 195°C to 210°C for 5 min, the temperature is decreased from 210°C to 185°C for 5 min, and the temperature is decreased from 185°C to 140°C for 10 min; The pressing pressure is controlled as follows: according to the time sequence, at 70PSI / cm 2 , 150PSI / cm 2 , 200PSI / cm 2 、300PSI / cm 2 、350PSI / cm 2 , 360PSI / cm 2 , 200PSI / cm 2 and 150PSI / cm 2 The holding time under pressure is 0min, 15min, 10min, 5min, 3min, 90min, 5min and 15min respectively; and in the control of the pressing pressure, the pressure is 70PSI / cm 2 Boost pressure to 150PSI / cm 2 The pressure rise time is 2 minutes, from 150PSI / cm 2 Boost pressure to 200PSI / cm 2 The pressure rise time is 2 minutes, from 200PSI / cm 2 Boost pressure to 300PSI / cm 2 The pressure rise time is 5 minutes, from 300PSI / cm 2 Boost pressure to 350PSI / cm 2 The pressure rise time is 2 minutes, from 350PSI / cm 2 Boost pressure to 360PSI / cm 2 The pressure rise time is 3 minutes, from 360PSI / cm 2 Reduce blood pressure to 200 PSI / cm 2 The decompression time is 5 minutes, from 200PSI / cm 2 Reduce blood pressure to 150 PSI / cm 2 The decompression time is 5 minutes.

[0048] It can be understood that this embodiment adjusts and optimizes the pressing temperature and pressing pressure at each stage of the above-mentioned pressing process, especially combines the preferably set heating and cooling time and pressure increasing and decreasing time (equivalent to combining the optimally controlled heating and cooling rate and pressure increasing and decreasing rate), which can effectively improve the filling capacity of the colloid during the pressing process, overcome the voids and stratification problems caused by the small amount of gas generated during the pressing process and the flow of the colloid, and greatly improve the pressing quality.

[0049] In addition, if the board obtained after completing the above S1 to S5 is defined as the intermediate board (see the attached Figure 9As shown), this embodiment also includes S6: the obtained intermediate board is subjected to conventional double-sided build-up layers (including insulation build-up layers and copper foil build-up layers), double-sided outer layer pattern production (the specific production process can refer to the double-sided inner layer pattern production), solder masking, surface treatment, molding, finished product testing, finished product inspection, packaging and other processing steps in sequence to obtain a final circuit board product.

[0050] From the above, it can be seen that this embodiment 1 innovatively arranges multiple flow-blocking blocks 20 around the window 4, and then improves and optimizes the combination method of the copper block 1 and the window 4, the pressing treatment method, etc., which can effectively improve the filling capacity of the colloid and achieve a more substantial colloid filling, thereby effectively reducing defects such as voids and delamination caused by uneven colloid flow, thereby significantly improving the bonding strength between the copper block 1 and the surrounding substrate, and significantly improving the reliability and stability of the circuit board product.

[0051] Example 2

[0052] This embodiment 2 also provides a method for manufacturing a buried copper block circuit board, and compared with embodiment 1, the manufacturing method provided by this embodiment 2 has the following differences: ① The specific method of this embodiment 2 for manufacturing double-sided inner layer graphics of the core board 2 is different from that of embodiment 1.

[0053] Specifically, this second embodiment uses the mSAP process to pattern the inner layers on both sides of the core substrate 2. As will be appreciated, the mSAP process is a conventional technique in the field of circuit board processing, typically comprising the following steps: lamination pretreatment, resist coating, exposure, development, pattern plating, film stripping, baking, and flash etching. Because this is a well-known technique, it will not be described in detail here.

[0054] In addition to the above-mentioned differences, the structures of the copper block 1, core board 2 and insulating layer 3 used in this embodiment 2, the layout of the baffle block 20, the manufacturing method of the window 4, the pressing method, the double-sided outer layer graphic production, solder mask, surface treatment, molding, etc. can all adopt the same technical means as in embodiment 1, so they will not be repeated here.

[0055] Example 3

[0056] This embodiment 3 provides a buried copper block circuit board, which is manufactured using the manufacturing method of the buried copper block circuit board provided in the above embodiment 1 or embodiment 2.

[0057] For details, please refer to the attached Figure 9As shown, the structure of the buried copper block circuit board is as follows: it includes a copper block 1, a core board 2 and an insulating layer 3, the two outer layers of the core board 2 are respectively provided with an inner layer circuit pattern 23 and a soldering pad, and one of the outer layers of the core board 2 is also provided with a plurality of baffles 20; the two insulating layers 3 are respectively fixed on the two outer layers of the core board 2, the copper block 1 is partially buried in one of the insulating layers 3 and partially buried in the core board 2, and at the same time, a plurality of baffles 20 are also arranged around the outside of the copper block 1.

[0058] From the above, it can be seen that the buried copper block circuit board obtained in this embodiment 3 has very high structural stability and reliability, and well meets the market demand for high-power electronic products.

[0059] Finally, the suffixes "A", "B", "C", etc. in the component names in this application description (such as board A, board B, board C, etc.) are only for the convenience of description and are not used to limit the scope of implementation of the patent of this invention.

[0060] In the above description, many specific details are set forth in order to fully understand the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for manufacturing a buried copper block circuit board, characterized in that: The production steps include: S1: providing a copper block (1) and a core board (2), wherein the surface of the copper block (1) is a rough surface, both outer layers of the core board (2) are copper foil layers, and a window position A is provided on a non-circuit area of ​​one of the outer layers of the core board (2), wherein the window position A is a position where a window needs to be opened in subsequent processing; S2: double-sided inner layer patterning is performed on the core board (2), so as to respectively produce inner layer circuit patterns and pads on the two outer layers of the core board (2), and a plurality of flow blocking blocks (20) arranged outside the window position A are also produced on an outer layer of the core board (2); S3: insulating layers (3) are respectively provided on the two outer layers of the core plate (2), and a window position B corresponding to the window position A is provided on one of the insulating layers (3) adjacent to the baffle block (20); S4: opening windows on the insulating layer (3) and the core plate (2) based on the window opening position B and the window opening position A to obtain a window (4); S5: The copper block (1) is placed in the window (4) and then pressed together. During the pressing process, the flow of the colloid in the window (4) is controlled by the flow blocking block (20) to achieve a firm combination of the copper block (1), the insulating layer (3) and the core plate (2).

2. The method for manufacturing a copper-buffered circuit board according to claim 1, wherein: The copper block (1) is provided with an outer convex structure and / or an inner concave structure on its peripheral side surface, and the shape of the window (4) matches the shape of the copper block (1) to achieve a snap-fit ​​connection between the two; In addition, after the copper block (1) is placed in the window (4), a gap of 0.025 mm to 0.05 mm is formed between the peripheral side surface of the copper block (1) and the inner side wall of the window (4).

3. The method for manufacturing a buried copper block circuit board according to claim 2, wherein: Chamfers with a radius of 0.5 mm to 2 mm are respectively processed at the four corners of the copper block (1).

4. The method for manufacturing a copper-buffered circuit board according to claim 1, wherein: The surface of the copper block (1) is roughened by a sandblasting process, a wire drawing process or a browning process, and the surface roughness of the copper block (1) is controlled to be Ra≥0.15μm and Rz≥1.5μm.

5. The method for manufacturing a buried copper block circuit board according to claim 1, wherein: In the above S2, the double-sided inner layer pattern is produced by a subtractive process or an mSAP process; wherein the subtractive process includes the following steps: pre-lamination treatment, coating with a resist photosensitive film, exposure, development, etching, and film stripping; and the mSAP process includes the following steps: pre-lamination treatment, coating with a resist photosensitive film, exposure, development, pattern electroplating, film stripping, baking, and flash etching; In addition, after the above S2 is completed, the window position A is a copper-free area.

6. The method for manufacturing a copper-buried circuit board according to claim 5, wherein: The line width and line spacing of the exposure material are 4 mil respectively, and the exposure energy is 200-250 MJ / cm 2 ; The developing speed is 3-3.3 m / min; The line width of the inner layer circuit pattern is 5-10 μm, and the line spacing is 5-10 μm; the copper thickness of the inner layer circuit pattern, the pad, and the current blocking block (20) are 30-35 μm respectively.

7. The method for manufacturing a copper-buffered circuit board according to claim 1, wherein: In the above S3, the insulating layer (3) is fixedly arranged on the outer layer of the core board (2) through a lamination process, and the insulating layer (3) adopts a semi-cured sheet or pure glue.

8. The method for manufacturing a buried copper block circuit board according to claim 1, wherein: In the above S4, a UV picosecond laser is used to open windows on the insulating layer (3) and the core plate (2), and the processing parameters of the UV picosecond laser are: output power of 1000 to 3000 W, repetition frequency of 100 to 250 Hz, laser scanning speed of 50 to 100 mm / s, and number of scans of 1 to 2 times.

9. The method for manufacturing a copper-buffered circuit board according to claim 1, wherein: In the pressing process of S5, the pressing temperature is controlled as follows: in a time sequence, the holding times at temperatures of 140°C, 155°C, 165°C, 180°C, 195°C, 210°C, 180°C and 140°C are 29 min, 4 min, 0 min, 0 min, 5 min, 75 min, 5 min and 10 min, respectively; and in the control of the pressing temperature, the temperature is raised from 140°C to 155°C for 6 min, from 155°C to 165°C for 5 min, from 165°C to 180°C for 3 min, from 180°C to 195°C for 5 min, from 195°C to 210°C for 5 min, from 210°C to 185°C for 5 min, and from 185°C to 140°C for 10 min; The pressing pressure is controlled as follows: according to the timing, at a pressure of 70PSI / cm 2 , 150PSI / cm 2 , 200PSI / cm 2 、300PSI / cm 2 、350PSI / cm 2 , 360PSI / cm 2 , 200PSI / cm 2 and 150PSI / cm 2 The holding time under the pressure is 0min, 15min, 10min, 5min, 3min, 90min, 5min and 15min respectively; and in the control of the pressing pressure, the pressure is 70PSI / cm 2 Boost pressure to 150PSI / cm 2 The pressure rise time is 2 minutes, from 150PSI / cm 2 Boost pressure to 200PSI / cm 2 The pressure rise time is 2 minutes, from 200PSI / cm 2 Boost pressure to 300PSI / cm 2 The pressure rise time is 5 minutes, from 300PSI / cm 2 Boost pressure to 350PSI / cm 2 The pressure rise time is 2 minutes, from 350PSI / cm 2 Boost pressure to 360PSI / cm 2 The pressure rise time is 3 minutes, from 360PSI / cm 2 Reduce blood pressure to 200 PSI / cm 2 The decompression time is 5 minutes, from 200PSI / cm 2 Reduce blood pressure to 150 PSI / cm 2 The decompression time is 5 minutes.

10. A buried copper block circuit board, characterized in that: The circuit board is manufactured by the method for manufacturing a buried copper block circuit board according to any one of claims 1 to 9.

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