Copper-embedded block circuit board and method for manufacturing the same

Abstract

The application discloses a kind of buried copper block circuit board and its manufacturing method, the manufacturing method includes: the two outer layers of core plate are copper foil layer, and window position A is provided on the non-line area of one outer layer;Core plate is double-sided inner layer pattern production, to make inner layer circuit pattern and pad on the two outer layers of core plate respectively, and make a plurality of flow blockings on one outer layer of core plate, which are surrounded outside window position A;The insulating layer is covered on the two outer layers of core plate, and window position B is provided on the insulating layer adjacent to flow blocking, which is opposite to window position A;Based on window position, insulating layer and core plate are windowed;After the copper block gap with rough surface is placed in window, it is compressed and handled, and in the process of compression, the flow of colloid in window is controlled by flow blocking, so that copper block is firmly combined with insulating layer and core plate together.The manufacturing method is simple and reasonable, easy to implement, the reliability and stability of the obtained circuit board product are high, and the market demand is met.

Description

Technical Field

[0001] This invention relates to the field of circuit board processing technology, and in particular to a copper-embedded circuit board and its manufacturing method. Background Technology

[0002] With the rapid development of the new energy industry, PCB boards are increasingly used in high-power electronic products such as motor controller boards, inverters, and power modules. At the same time, due to the concentrated heat dissipation and high current carrying capacity of high-power components such as LED light sources, integrated circuits, and capacitors during operation, higher requirements are placed on the heat dissipation, conductivity, material mechanical strength, and thermal stress performance of PCB boards.

[0003] To improve the heat dissipation performance of PCBs, the current industry practice is to create a groove on the PCB, place a large copper block (or ceramic body) into the groove, and then press them together to bond the copper block (or ceramic body) to the PCB. However, due to poor adhesion and inconsistent thermal conductivity between the copper block (or ceramic) and the insulating layer (such as prepreg) on ​​the PCB, the copper surface (or ceramic surface) is prone to concentrated heat during subsequent high-temperature processes such as tin plating. This can lead to defects such as delamination and cracking of the insulating layer around the copper block (or ceramic), severely affecting the yield of the finished PCB.

[0004] To overcome the aforementioned technical problems, the industry has made many technical improvements, such as increasing the number of prepreg sheets or using prepreg sheets with high adhesive content to improve the bonding strength between the prepreg sheet and the copper block (or ceramic). However, these improvements have only moderate effects, cannot fundamentally solve the problem, and are costly. In view of this, the present invention is proposed. Summary of the Invention

[0005] To overcome the above-mentioned defects, the present invention provides a copper-embedded circuit board and its manufacturing method. The manufacturing method is simple, reasonable and easy to operate and implement, and the resulting circuit board product has very high reliability and stability, which well meets the market demand for high-power electronic products.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for manufacturing a copper-embedded circuit board, comprising the following manufacturing steps:

[0007] S1: Provide a copper block and a core board. The surface of the copper block is rough. Both outer layers of the core board are copper foil layers. A window position A is provided in the non-circuit area of ​​one of the outer layers of the core board. The window position A is the position where a window needs to be opened in subsequent processing.

[0008] S2: The core board is patterned on both sides to create inner layer circuit patterns and pads on the two outer layers of the core board, and multiple flow blocking blocks surrounding the window position A are also created on one outer layer of the core board.

[0009] S3: An insulating layer is respectively applied to the two outer layers of the core board, and an opening position B corresponding to the opening position A is provided on one of the insulating layers adjacent to the flow blocking block;

[0010] S4: Create a window by opening a window in the insulating layer and the core board based on the window opening position B and the window opening position A;

[0011] S5: After the copper block is placed in the window, it is pressed together. During the pressing process, the flow control block is used to control the flow of the colloid in the window, so as to make the copper block firmly bonded to the insulating layer and the core board.

[0012] As a further improvement of the present invention, the peripheral side of the copper block is provided with an outward convex structure and / or an inward concave structure, and the shape of the window matches the shape of the copper block to achieve a snap-fit ​​connection between the two.

[0013] In addition, after the copper block is placed in the window, there is a gap of 0.025mm to 0.05mm between the peripheral side of the copper block and the inner sidewall of the window.

[0014] As a further improvement of the present invention, chamfers with radii of 0.5 mm to 2 mm are machined at the four corners of the copper block.

[0015] As a further improvement of the present invention, the surface of the copper block is roughened by sandblasting, wire drawing or browning process, and the surface roughness of the copper block is controlled at Ra≥0.15μm and Rz≥1.5μm.

[0016] As a further improvement of the present invention, in S2 above, the double-sided inner layer pattern is fabricated using a subtractive process or an mSAP process; wherein, the subtractive process includes sequential steps of pre-coating treatment, coating with a photosensitive resist film, exposure, development, etching, and stripping; the mSAP process includes sequential steps of pre-coating treatment, coating with a photosensitive resist film, exposure, development, pattern electroplating, stripping, baking, and flash etching.

[0017] In addition, after completing S2 above, the window position A is a copper-free area.

[0018] As a further improvement of the present invention, the line width and line spacing of the exposure data are both 4 mil, and the exposure energy is 200-250 MJ / cm. 2The developing speed is 3–3.3 m / min.

[0019] 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 choke block is 30-35 μm, respectively.

[0020] As a further improvement of the present invention, in S3 above, the insulating layer is fixedly disposed on the outer layer of the core board by a lamination process, and the insulating layer is a prepreg or pure adhesive.

[0021] As a further improvement of the present invention, in S4 above, 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 scanning times of 1-2 times.

[0022] As a further improvement of the present invention, in the pressing process of S5 above, the pressing temperature is controlled as follows: proceeding sequentially, the holding times at temperatures of 140℃, 155℃, 165℃, 180℃, 195℃, 210℃, 180℃, and 140℃ 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 increases from 140℃... The heating time from 155℃ to 165℃ is 6 minutes, the heating time from 155℃ to 165℃ is 5 minutes, the heating time from 165℃ to 180℃ is 3 minutes, the heating time from 180℃ to 195℃ is 5 minutes, the heating time from 195℃ to 210℃ is 5 minutes, the cooling time from 210℃ to 185℃ is 5 minutes, and the cooling time from 185℃ to 140℃ is 10 minutes.

[0023] The pressing pressure is controlled as follows: It is performed sequentially, with holding times at pressures of 70 PSI, 150 PSI, 200 PSI, 300 PSI, 350 PSI, 360 PSI, 200 PSI, and 150 PSI being 0 min, 15 min, 10 min, 5 min, 3 min, 90 min, 5 min, and 15 min respectively; and in the control of the pressing pressure, the pressure increase time from 70 PSI to 150 PSI is 2 minutes. The boost time from 150 PSI to 200 PSI is 2 minutes, the boost time from 200 PSI to 300 PSI is 5 minutes, the boost time from 300 PSI to 350 PSI is 2 minutes, the boost time from 350 PSI to 360 PSI is 3 minutes, the deboost time from 360 PSI to 200 PSI is 5 minutes, and the deboost time from 200 PSI to 150 PSI is 5 minutes.

[0024] The present invention also provides a copper-embedded circuit board, which is manufactured using the copper-embedded circuit board manufacturing method described in the present invention.

[0025] The beneficial effects of this invention are: ① By innovatively arranging multiple flow-blocking blocks around the window, and combining this with improvements and optimizations to the bonding method between the copper block and the window, as well as the pressing process, this invention effectively enhances the filling capacity of the colloid and achieves a more complete colloid filling. This effectively reduces 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 manufacturing method of the embedded copper block circuit board of this invention is simple, reasonable, novel, and easy to implement in production. Furthermore, the resulting embedded copper block circuit board is of high quality and can well meet the market demand for high-power electronic products. Attached Figure Description

[0026] Figure 1 This is a process flow diagram of the method for manufacturing the embedded copper block circuit board described in Embodiment 1 of the present invention;

[0027] Figure 2 This is one of the cross-sectional structural diagrams of the copper block described in Example 1;

[0028] Figure 3 This is the second schematic diagram of the cross-sectional structure of the copper block described in Example 1;

[0029] Figure 4 This is a schematic cross-sectional view of the core board described in Example 1;

[0030] Figure 5 This is a schematic cross-sectional view of board A obtained after completing the double-sided inner layer pattern fabrication of the core board in Example 1;

[0031] Figure 6 This is a schematic cross-sectional view of board B obtained after applying an insulating layer to both sides of board A in Example 1.

[0032] Figure 7 This is a schematic cross-sectional view of the board C obtained after opening a window in the board B in Example 1.

[0033] Figure 8 for Figure 7 A schematic cross-sectional view of the window shown in the image from another perspective;

[0034] Figure 9 This is a schematic cross-sectional view of the intermediate plate obtained in Example 1.

[0035] Referring to the accompanying drawings, the following explanations are provided:

[0036] 1. Copper block; 10. Main body; 11. Outward convex structure; 2. Core board; 20. Current blocking block; 21. Insulating intermediate layer; 22. Copper foil layer; 23. Inner layer circuit pattern; 3. Insulating layer; 4. Window; 40. Inward concave structure. Detailed Implementation

[0037] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0038] Example 1:

[0039] Please see the appendix Figure 1 As shown, this embodiment 1 provides a method for manufacturing a copper-embedded circuit board, including the following manufacturing steps:

[0040] S1: Provides copper block 1 and core board 2.

[0041] In this embodiment 1, the surface of the copper block 1 is preferably designed to be rough to improve the bonding strength when the copper block 1 is combined with other components / materials such as the core board 2 in subsequent processes.

[0042] Furthermore, in this embodiment 1, the surface of the copper block 1 is roughened by sandblasting, wire drawing or browning processes, and the surface roughness of the copper block 1 is controlled to Ra≥0.15μm and Rz≥1.5μm to achieve the best bonding performance of the copper block 1.

[0043] In addition, to further improve the bonding quality between the copper block 1 and the core board 2 and other components / materials, this embodiment 1 also specifically improves the structure of the copper block 1, as follows: Please refer to the appendix. Figure 2 and attached Figure 3As shown, the copper block 1 has a block-shaped main body 10 and an integrally formed protruding structure 11 on the peripheral side of the main body 10. The four corners of the main body 10 are respectively machined with rounded chamfers with radii of 0.5mm to 2mm. This ensures the flatness and fit of the copper block 1 when placed into the window 4 in the subsequent process. The protruding structure 11 is used to snap-fit ​​with the window 4 in the subsequent process, ensuring that the copper block 1 will not deviate during the pressing process, thus ensuring a stable and firm connection between the copper block 1 and the window 4. The specific shape of the protruding structure 11 can be, but is not limited to, a wavy shape (see appendix). Figure 3 (as shown) or swallowtail shape (see appendix) Figure 2 (As shown).

[0044] Supplementary notes: ① The size and shape of the chamfered corners at the four corners of the main body 10 can be consistent or inconsistent, depending on the design requirements of the circuit board product. This embodiment 1 does not impose any restrictions. ② In addition to providing the protruding structure 11 on the copper block 1, the protruding structure 11 can also be replaced with a concave structure, or a combination of protruding and concave structures can be provided on the copper block 1; it is understood that as long as the copper block 1 and the window 4 can be connected by a snap-fit ​​mechanism, it is acceptable.

[0045] 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.

[0046] Understandably, depending on the processing requirements of the circuit board product, the core board 2 can adopt various types of working boards. However, for the sake of convenience in describing the manufacturing method of the embedded copper block circuit board described in this application, this embodiment 1 uses a double-sided copper-clad laminate as an example for illustration. That is, the structure of the core board 2 is as follows: Please refer to the attached... Figure 4 As shown, the core board 2 is provided with an insulating intermediate layer 21 and two copper foil layers 22 respectively 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. The opening position A is provided on the non-circuit area of ​​one of the copper foil layers 22.

[0047] S2: Double-sided inner layer patterning is performed on the core board 2 to create inner layer circuit patterns and pads on the two outer layers of the core board 2, and multiple flow blocking blocks 20 surrounding the window position A are also created on one outer layer of the core board 2; at that time, board A is obtained.

[0048] Specifically, in this embodiment 1, a subtractive process is used to fabricate the double-sided inner layer pattern of the core board 2. The specific fabrication method is as follows:

[0049] ① Pre-coating treatment: The two copper foil layers 22 of the core board 2 are sequentially roughened, cleaned, and dried to enhance the adhesion between the photosensitive dry film and the copper foil layers 22 in subsequent processes. The roughening treatment can preferably be, but is not limited to, ceramic grinding or micro-etching.

[0050] ② Applying the photosensitive anti-corrosion film: The photosensitive anti-corrosion dry film is applied to the two copper foil layers 22 using a vacuum laminator. Understandably, the vacuum laminator can achieve a high degree of flatness in the lamination process, effectively improving the adhesion between the photosensitive anti-corrosion dry film and the copper foil layers 22.

[0051] ③ Exposure and development: Using an LDI exposure machine and according to the work instructions, expose a portion of the resist photosensitive dry film, and then develop and remove the unexposed areas of the resist photosensitive dry film.

[0052] Furthermore, in this embodiment 1, the specific processing conditions for exposure and development are optimized as follows: the line width and line spacing of the exposed data are both 4 mil, and the exposure energy is 200-250 MJ / cm. 2 The development speed is 3–3.3 m / min to achieve better production of inner layer patterns.

[0053] ④ Etching: Use an alkaline etching solution to remove the portions of the two copper foil layers 22 that are not covered by the photosensitive dry film.

[0054] ⑤ Film Removal: The photoresist dry film on the core board 2 is completely removed using a strongly alkaline solution. This allows for the fabrication of inner layer patterns on the two copper foil layers 22. See the appendix for details. Figure 5 As shown.

[0055] Understandably, according to the circuit board product design requirements, inner layer circuit patterns 23 and pads are respectively fabricated on both copper foil layers 22. Furthermore, multiple current-blocking blocks 20 are fabricated around the opening position A on the non-circuit area of ​​the copper foil layer 22 where the opening position A is located. Supplementary explanation: ① After the inner layer pattern fabrication is completed, the opening position A can be a copper-containing area or a copper-free area. However, to facilitate subsequent opening operations, this embodiment 1 is preferably designed such that after the double-sided inner layer pattern fabrication (i.e., S2 above), the opening position A is a copper-free area, exposing a portion of the insulating intermediate layer 21. For details, please refer to the appendix. Figure 5 The area indicated by mark A. ② Because the multiple flow-blocking blocks 20 are arranged in non-circuit areas and spaced apart by a set gap, they will not affect the electrical performance of the circuit board product.

[0056] Furthermore, according to the circuit board product design requirements and the above-mentioned double-sided inner layer pattern fabrication method, the technical parameters of the obtained inner layer pattern in this embodiment 1 are as follows: the line width of the inner layer circuit pattern 23 is 5-10 μm and the line spacing is 5-10 μm; the copper thickness of the inner layer circuit pattern 23, the pad and the current blocking block 20 are 30-35 μm respectively.

[0057] Furthermore, based on the copper thickness requirements of the obtained inner layer pattern, in this embodiment 1, before performing the above-mentioned pre-coating process, a whole-board electroplating process can be performed to ensure that the copper thickness meets the requirements of the circuit board product.

[0058] S3: An insulating layer 3 is respectively applied to the two outer layers of the core board 2, and an opening position B corresponding to the opening position A is provided on one of the insulating layers 3 adjacent to the flow blocking block 20, thus obtaining board B (see appendix). Figure 6 (As shown).

[0059] Specifically, after completing S2 above, the insulating layer 3 can be fixedly disposed on the two copper foil layers 22 of the core board 2 by a lamination process, and the insulating layer 3 can preferably be a prepreg or pure adhesive. Further, in this embodiment 1, the insulating layer 3 is a prepreg.

[0060] Notes: ① The above lamination process is a conventional technique in the field of circuit board processing, and therefore 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 the specific requirements will be determined according to the processing needs.

[0061] S4: Based on the window opening positions B and A, windows are made in the insulating layer 3 and the core board 2 to obtain window 4. See attached document. Figure 7 As shown; and at that time, board C will be obtained.

[0062] Specifically, since the window opening position B and the window opening position A are correspondingly arranged (or can be understood as being directly opposite each other), this embodiment 1 can use a laser (preferably a UV picosecond laser) and based on the window opening positions B and A to sequentially perform window opening operations on the insulating layer 3 and the core board 2 to obtain the window 4. Please continue to refer to the appendix. Figure 7 As shown, the window 4 can be understood as a blind slot structure with a portion of the insulating intermediate layer 21 as a groove and an opening on a surface of the insulating layer 3 facing away from the core board 2.

[0063] Furthermore, 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.

[0064] Furthermore, the shape of the window 4 matches the shape of the copper block 1, so that the copper block 1 can be inserted into the window 4 and the two can be connected by a snap-fit ​​mechanism; specifically, when the copper block 1 has an outwardly protruding structure 11 on its peripheral side, the window 4 has an inwardly concave structure 40 that engages with the outwardly protruding structure 11 (see Appendix). Figure 8 (as shown); and when the 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 engages with the concave structure A.

[0065] 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 of the copper block 1 and the inner sidewall of the window 4; so as to control the appropriate amount of glue filling.

[0066] S5: After the copper block 1 is placed in the window 4, it is pressed together. During the pressing process, the flow control block 20 controls the flow of the colloid in the window 4 to ensure that the copper block 1 is firmly bonded to the insulating layer 3 and the core board 2. For details, please refer to the appendix. Figure 9 As shown. Understandably, during the pressing process, the insulating layer 3 is heated and melts into a colloid, which fills 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 out after pressing. This enables the colloid to be filled more completely, reducing defects such as voids and delamination caused by uneven colloid flow. In turn, it improves the bonding strength between the copper block 1 and the surrounding substrate, and improves the reliability and stability of the circuit board.

[0067] In addition, this embodiment 1 further optimizes the processing parameters (especially pressing temperature and pressing pressure) of the above-mentioned pressing process to further improve the pressing quality. Specifically, in the above-mentioned pressing process, the pressing temperature is controlled as follows: The holding times at 140℃, 155℃, 165℃, 180℃, 195℃, 210℃, 180℃, and 140℃ are 29 min, 4 min, 0 min, 0 min, 5 min, 75 min, 5 min, and 10 min, respectively. Furthermore, in the control of the pressing temperature, the temperature rise time from 140℃ to 155℃ is 6 min, from 155℃ to 165℃ is 5 min, from 165℃ to 180℃ is 3 min, from 180℃ to 195℃ is 5 min, from 195℃ to 210℃ is 5 min, from 210℃ to 185℃ is 5 min, and from 185℃ to 140℃ is 10 min.

[0068] The pressing pressure is controlled as follows: It is performed sequentially, with holding times at 70 PSI, 150 PSI, 200 PSI, 300 PSI, 350 PSI, 360 PSI, 200 PSI, and 150 PSI being 0 min, 15 min, 10 min, 5 min, 3 min, 90 min, 5 min, and 15 min respectively; and in the control of the pressing pressure, the pressure increase time from 70 PSI to 150 PSI is 2 minutes. The boost time from 150 PSI to 200 PSI is 2 minutes, the boost time from 200 PSI to 300 PSI is 5 minutes, the boost time from 300 PSI to 350 PSI is 2 minutes, the boost time from 350 PSI to 360 PSI is 3 minutes, the deboost time from 360 PSI to 200 PSI is 5 minutes, and the deboost time from 200 PSI to 150 PSI is 5 minutes.

[0069] Understandably, this embodiment optimizes the pressing temperature and pressing pressure at each stage of the pressing process, especially by combining the preferred heating and cooling times and the heating and cooling pressure times (which is equivalent to combining the optimal heating and cooling rates and the optimal heating and cooling pressure rates). This effectively improves the filling capacity of the colloid during the pressing process, overcomes the problems of voids and delamination caused by the small amount of gas generated during the pressing process and the flow of colloid, and greatly improves the pressing quality.

[0070] Additionally, if the board produced after completing S1 to S5 is defined as the intermediate board (see Appendix),... Figure 9 As shown), this embodiment also includes S6: After performing conventional double-sided layering (including insulation layering and copper foil layering), double-sided outer layer pattern making (the specific manufacturing process can be referred to the double-sided inner layer pattern making), solder resist, surface treatment, molding, finished product testing, finished product inspection, packaging and other processing steps on the obtained intermediate board, the final circuit board product is obtained.

[0071] As can be seen from the above, this embodiment 1, by innovatively arranging multiple flow-blocking blocks 20 around the window 4, and by improving and optimizing the bonding method between the copper block 1 and the window 4, as well as the pressing process, can effectively enhance the filling capacity of the colloid and achieve a more complete colloid filling. This effectively reduces 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.

[0072] Example 2:

[0073] This embodiment 2 also provides a method for manufacturing a copper-embedded circuit board. Compared with embodiment 1, the manufacturing method provided in this embodiment 2 has the following differences: ① The specific method for manufacturing the double-sided inner layer pattern of the core board 2 in this embodiment 2 is different from that in embodiment 1.

[0074] Specifically, in this embodiment 2, the mSAP process is used to fabricate the double-sided inner layer pattern of the core board 2. It is understood that the mSAP process is a conventional technique in the field of circuit board manufacturing, and it typically includes the following steps: pre-coating treatment, coating with a photosensitive resist film, exposure, development, pattern electroplating, film removal, baking, and flash etching. Since this is a well-known technique, it will not be described in detail here.

[0075] Apart from the differences mentioned above, the structure of the copper block 1, core board 2, and insulating layer 3 used in this embodiment 2, the layout of the flow blocking block 20, the manufacturing method of the window 4, the pressing process, the fabrication of the double-sided outer layer pattern, the soldering, the surface treatment, the forming, etc., can all adopt the same technical means as in embodiment 1, so they will not be described in detail here.

[0076] Example 3:

[0077] This embodiment 3 provides a copper-embedded circuit board, which is manufactured using the copper-embedded circuit board manufacturing method provided in embodiment 1 or embodiment 2 above.

[0078] For details, please refer to the appendix. Figure 9 As shown, the structure of the embedded 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 inner layer circuit patterns 23 and pads, and one of the outer layers of the core board 2 is also provided with multiple current blocking blocks 20. The two insulating layers 3 are respectively fixedly disposed on the two outer layers of the core board 2. The copper block 1 is partially embedded in one of the insulating layers 3 and partially embedded in the core board 2. At the same time, the multiple current blocking blocks 20 are also partially surrounding the copper block 1.

[0079] As can be seen from the above, the embedded copper block circuit board obtained in this embodiment 3 has very high structural stability and reliability, which well meets the market demand for high-power electronic products.

[0080] Finally, the suffixes "A", "B", "C", etc. in the component names in this application specification (such as board A, board B, board C, etc.) are only for ease of description and are not intended to limit the scope of implementation of this invention patent.

[0081] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a copper-embedded circuit board, characterized in that: The production process includes the following steps: S1: Provide a copper block (1) and a core board (2). The surface of the copper block (1) is rough. Both outer layers of the core board (2) are copper foil layers. A window position A is provided in 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. S2: Double-sided inner layer patterning is performed on the core board (2) to create inner layer circuit patterns and pads on the two outer layers of the core board (2) respectively, and multiple flow blocking blocks (20) surrounding the window position A are also created on one outer layer of the core board (2). S3: An insulating layer (3) is fixedly applied to the two outer layers of the core board (2) by a lamination process. The insulating layer (3) is made of prepreg or pure adhesive. An opening position B corresponding to the opening position A is provided on one of the insulating layers (3) adjacent to the flow blocking block (20). S4: Based on the window opening position B and the window opening position A, the insulating layer (3) and the core board (2) are opened to obtain the window (4). S5: After the copper block (1) is placed in the window (4) with a gap, it is pressed. During the pressing process, the flow control block (20) is used to control the flow of the colloid in the window (4) so ​​as to make the copper block (1) firmly bonded to the insulating layer (3) and the core board (2).

2. The method for manufacturing a copper-embedded circuit board according to claim 1, characterized in that: The copper block (1) has an outward convex structure and / or an inward concave structure on its peripheral side surface. The shape of the window (4) matches the shape of the copper block (1) to achieve a snap-fit ​​connection between the two. After the copper block (1) is placed into the window (4), there is a gap of 0.025 mm to 0.05 mm between the peripheral side of the copper block (1) and the inner sidewall of the window (4).

3. The method for manufacturing a copper-embedded circuit board according to claim 2, characterized in that: Chamfers with radii of 0.5 mm to 2 mm are machined at the four corners of the copper block (1).

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

5. The method for manufacturing a copper-embedded circuit board according to claim 1, characterized in that: In S2 above, the double-sided inner layer pattern is fabricated using a subtractive process or an mSAP process; wherein, the subtractive process includes sequential steps of pre-coating treatment, coating with a photosensitive resist film, exposure, development, etching, and stripping; the mSAP process includes sequential steps of pre-coating treatment, coating with a photosensitive resist film, exposure, development, pattern electroplating, stripping, baking, and flash etching. After completing S2 above, the window position A is a copper-free area.

6. The method for manufacturing a copper-embedded circuit board according to claim 5, characterized in that: The line width and line spacing of the exposed data are 4 mil, 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) is 30-35 μm.

7. The method for manufacturing a copper-embedded circuit board according to claim 1, characterized in that: In the above S4, a UV picosecond laser is used to open the insulating layer (3) and the core board (2), 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 scanning times of 1-2 times.

8. The method for manufacturing a copper-embedded circuit board according to claim 1, characterized in that: In the pressing process of S5 above, the pressing temperature is controlled as follows: it is carried out in sequence, and the holding times at temperatures of 140℃, 155℃, 165℃, 180℃, 195℃, 210℃, 180℃ and 140℃ are 29min, 4min, 0min, 0min, 5min, 75min, 5min and 10min respectively; and in the control of the pressing temperature, the heating time from 140℃ to 155℃ is 6min, the heating time from 155℃ to 165℃ is 5min, the heating time from 165℃ to 180℃ is 3min, the heating time from 180℃ to 195℃ is 5min, the heating time from 195℃ to 210℃ is 5min, the cooling time from 210℃ to 185℃ is 5min, and the cooling time from 185℃ to 140℃ is 10min. The pressing pressure is controlled as follows: It is performed sequentially, with holding times at pressures of 70 PSI, 150 PSI, 200 PSI, 300 PSI, 350 PSI, 360 PSI, 200 PSI, and 150 PSI being 0 min, 15 min, 10 min, 5 min, 3 min, 90 min, 5 min, and 15 min respectively; and in the control of the pressing pressure, the pressure increase time from 70 PSI to 150 PSI is 2 minutes. The boost time from 150 PSI to 200 PSI is 2 minutes, the boost time from 200 PSI to 300 PSI is 5 minutes, the boost time from 300 PSI to 350 PSI is 2 minutes, the boost time from 350 PSI to 360 PSI is 3 minutes, the deboost time from 360 PSI to 200 PSI is 5 minutes, and the deboost time from 200 PSI to 150 PSI is 5 minutes.

9. A copper-embedded circuit board, characterized in that: It is manufactured using the method described in any one of claims 1-8 for the production of a copper-embedded circuit board.

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