Circuit board and method for manufacturing embedded copper block thereof

Abstract

The present disclosure provides a circuit board and a method for manufacturing a buried copper block, the method comprising: obtaining a first prepreg, a core plate, a second prepreg and a copper block respectively; performing a hole drilling operation on the first prepreg; performing a hole drilling operation on the core plate; performing a hole drilling operation on the second prepreg; performing a riveting operation on the first prepreg, the core plate and the second prepreg; turning up the first prepreg and burying the copper block to form a to-be-pressed board; performing a pressing operation on the to-be-pressed board to form a pressed board; pasting dry film on both sides of the pressed board; and performing an etching operation on the pressed board. The method uses a single core plate and two prepregs for pressing. Compared with the production method using two core plates with different thicknesses, the present scheme is less likely to cause the board to bend and warp during pressing. The scheme uses a buried mode with the boss facing upwards, so it is not necessary to align the boss with the first mounting hole slot position of the first prepreg, thereby reducing the difficulty of burying the copper block and improving the production efficiency.

Description

Technical Field

[0001] This disclosure relates to the technical field of circuit board manufacturing, and in particular to a circuit board and a method for manufacturing the same with embedded copper blocks. Background Technology

[0002] The existing method for manufacturing copper-embedded bosses is to use a core (core board) + core method and then use a covering material (three-in-one or aluminum sheet) to make it. Its disadvantages are high cost, asymmetrical lamination causing board warping, and low lamination layout efficiency.

[0003] The reason for the asymmetry in the stacking structure is that the stacking structure depends on the thickness of the copper block and the height of the boss. One core is matched with the height of the boss, and the other core is matched with the height of the copper block at the bottom of the boss. The thickness of the two cores will often be inconsistent.

[0004] In addition, the existing pressing and layout steps are as follows: cover material → riveting plate (core1+PP+core2) → copper block (boss facing down) → cover material. When embedding the copper block, it is necessary to align the boss with the mounting slot of the boss of core1, which is inefficient.

[0005] The existing method for manufacturing copper-embedded bosses is to use a core + RCC (Resin Coated Copper) method followed by a molding material (three-in-one or aluminum sheet). The disadvantage is that the cost of RCC slotting is high, and RCC is prone to quality problems such as wrinkling.

[0006] Therefore, to address the above issues, a feasible solution is needed to reduce the probability of board warping during circuit board lamination, lower manufacturing costs, and improve production efficiency. Summary of the Invention

[0007] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a circuit board and a method for manufacturing the embedded copper block thereof, which reduces the probability of board warping during circuit board lamination, reduces manufacturing costs, and improves production efficiency.

[0008] The purpose of this disclosure is achieved through the following technical solution:

[0009] A method for manufacturing embedded copper blocks in a circuit board includes the following steps:

[0010] S101. Obtain a first semi-cured board, a core board, a second semi-cured board, and a copper block, respectively. The copper block has a boss, and one side of the first semi-cured board and one side of the second semi-cured board both have a copper foil layer.

[0011] S102. Perform a milling operation on the first semi-cured plate to form a first mounting groove;

[0012] S103. Perform a milling operation on the core board to form a second mounting groove;

[0013] S104. Perform a milling operation on the second semi-cured plate to form a third mounting groove;

[0014] S105. The first semi-cured board, the core board and the second semi-cured board are riveted together so that the first semi-cured board, the core board and the second semi-cured board are arranged in sequence, wherein the first mounting groove, the second mounting groove and the third mounting groove are connected in sequence, and the width of the first mounting groove is less than the width of the second mounting groove, and the width of the second mounting groove is equal to the width of the third mounting groove.

[0015] S106. Open the first semi-cured plate and embed the copper block to form a plate to be pressed, wherein the copper block is accommodated in the second mounting groove and the third mounting groove, and the boss is accommodated in the first mounting groove. The boss protrudes from the top surface of the first semi-cured plate, and the side of the copper block away from the boss protrudes from the side of the second semi-cured plate away from the core plate.

[0016] S107. Perform a pressing operation on the plate to be pressed to form a pressed plate;

[0017] S108. Apply dry film to both sides of the pressed plate;

[0018] S109. Etching operation is performed on the laminated plate to remove the copper foil layer on the top surface of the boss and the copper foil layer on the side of the copper block away from the boss.

[0019] In one embodiment, S105 is executed, which specifically includes the following steps:

[0020] S1051. Drill holes in the first semi-cured plate to give the first semi-cured plate a first rivet hole.

[0021] S1052. Drill holes in the core board to give the first semi-cured board a second rivet hole and a third rivet hole.

[0022] S1053. Drill holes in the second semi-cured board to give the second semi-cured board a fourth rivet hole and a fifth rivet hole.

[0023] S1054. The first semi-cured board, the core board and the second semi-cured board are stacked, wherein the first rivet hole, the second rivet hole and the fourth rivet hole are connected in sequence, and the third rivet hole and the fifth rivet hole are connected.

[0024] S1055. The first semi-cured board, the core board and the second semi-cured board are sequentially stacked by two rivets, wherein one of the rivets is sequentially inserted through the first rivet hole, the second rivet hole and the fourth rivet hole, and the other rivet is sequentially inserted through the third rivet hole and the fifth rivet hole.

[0025] In one embodiment, the length of one of the rivets is greater than the length of the other rivet.

[0026] In one embodiment, the copper foil layer is a highly ductile copper foil.

[0027] In one embodiment, when S107 is performed, the pressing temperature is 200°C-220°C.

[0028] In one embodiment, when performing S107, the pressing time is 110 min-120 min.

[0029] In one embodiment, the boss extends 10-15 μm from the top surface of the first prepreg.

[0030] In one embodiment, the copper block extends 10-15 μm from the side of the second semi-cured plate away from the core plate on the side opposite to the boss.

[0031] In one embodiment, after executing S109, the following steps are then included:

[0032] The pressed board is polished so that the top of the boss is flush with the top of the first semi-cured board, and the side of the copper block away from the boss is flush with the side of the second semi-cured board away from the core board.

[0033] A circuit board is prepared using the circuit board embedded copper block manufacturing method described in any embodiment.

[0034] Compared with the prior art, this disclosure has at least the following advantages:

[0035] 1. The above-mentioned method for manufacturing embedded copper blocks in circuit boards uses a single core board and two semi-cured boards for lamination. Compared with the production method of using two core boards of different thicknesses, this method is less likely to cause board bending during lamination.

[0036] 2. This solution adopts an embedding method with the boss facing upwards. In the process of embedding the copper block, the first semi-cured plate is first opened, then the copper block is embedded, and finally the first semi-cured plate is covered. During this process, it is not necessary to align the boss with the first mounting groove of the first semi-cured plate, thereby reducing the difficulty of embedding the copper block and improving production efficiency.

[0037] 3. This solution uses a prepreg board instead of resin-coated copper foil (RCC). Compared with RCC, the prepreg board is less prone to wrinkling, which reduces the overall manufacturing cost of the circuit board. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart of a method for manufacturing embedded copper blocks on a circuit board in one embodiment;

[0040] Figure 2 This is a cross-sectional view of the circuit board structure when the copper block is embedded in the circuit board during the manufacturing method of embedding copper blocks in one embodiment;

[0041] Figure 3 for Figure 2 The diagram shown is a cross-sectional view of the circuit board after the copper block has been embedded.

[0042] Figure 4 for Figure 3 A partial cross-sectional view of the circuit board shown;

[0043] Figure 5 This is a cross-sectional view of the circuit board after grinding operations are completed in a method for manufacturing embedded copper blocks in a circuit board according to one embodiment.

[0044] Figure 6 for Figure 5 The diagram shows the corresponding structural effect of the circuit board.

[0045] Figure 7 This is a cross-sectional view of the circuit board structure when the copper block is embedded in the circuit board during the manufacturing method of embedding copper blocks in another embodiment;

[0046] Figure 8 for Figure 7 The diagram shows a cross-sectional view of the circuit board after the copper block has been embedded.

[0047] Reference numerals: 10a, First mounting rivet; 10b, Second mounting rivet; 100, First prepreg; 101, First mounting groove; 102, First rivet hole; 200, Core board; 201, Second mounting groove; 202, Second rivet hole; 203, Third rivet hole; 204, Rounded corner guide ring; 300, Second prepreg; 301, Third mounting groove; 302, Fourth rivet hole; 303, Fifth rivet hole; 400, Copper block; 401, Vertical channel; 402, Upper horizontal channel; 403, Lower horizontal channel; 410, Boss; 500, Copper foil layer. Detailed Implementation

[0048] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0049] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0051] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0052] Please see Figure 1 This is a method for manufacturing embedded copper blocks in a circuit board according to an embodiment of the present invention, which includes some or all of the following steps:

[0053] S101. Obtain the first prepreg board 100, core board 200, second prepreg board 300, and copper block 400 respectively to prepare for subsequent routing of the first prepreg board 100, core board 200, and second prepreg board 300. The copper block 400 has a boss 410, and one side of the first prepreg board 100 and one side of the second prepreg board 300 both have a copper foil layer 500, which is not routed. Specifically, the core board 200 can be a single substrate or a combination board formed by multiple substrates and multiple prepreg boards. Furthermore, the copper foil layer 500 on one side of the first prepreg board 100 and the copper foil layer 500 on one side of the second prepreg board 300 are both positioned away from the core board 200 so that during subsequent lamination, the copper foil layer 500 prevents the adhesive formed by the first prepreg board 100 and the second prepreg board 300 from flowing to the laminating steel plate, thereby preventing the adhesive from sticking to the laminating steel plate and causing circuit board delamination.

[0054] S102. Perform a milling operation on the first semi-cured plate 100 to form a first mounting milling groove 101;

[0055] S103. Perform a milling operation on the core board 200 to form a second mounting milling groove 201;

[0056] S104. Perform a milling operation on the second semi-cured plate 300 to form a third mounting groove 301;

[0057] Furthermore, the structural diagram of the first semi-cured plate 100, the core plate 200, and the second semi-cured plate 300 after drilling holes is as follows: Figure 2 As shown.

[0058] S105. The first semi-cured plate 100, the core plate 200, and the second semi-cured plate 300 are riveted together so that the first semi-cured plate 100, the core plate 200, and the second semi-cured plate 300 are arranged in sequence. The first mounting groove 101, the second mounting groove 201, and the third mounting groove 301 are connected in sequence. The width of the first mounting groove 101 is less than the width of the second mounting groove 201, and the width of the second mounting groove 201 is equal to the width of the third mounting groove 301, so that the embedded area formed by the first mounting groove 101, the second mounting groove 201, and the third mounting groove 301 can match the copper block 400.

[0059] S106, such as Figures 2 to 4As shown, the first semi-cured plate 100 is flipped open, and the copper block 400 is embedded to form a plate to be pressed together. The copper block 400 is accommodated in the second mounting groove 201 and the third mounting groove 301, and the boss 410 is accommodated in the first mounting groove 101. The boss 410 protrudes from the top surface of the first semi-cured plate 100, and the side of the copper block 400 facing away from the boss 410 protrudes from the side of the second semi-cured plate 300 facing away from the core plate 200. It can be understood that when embedding the copper block 400, the first semi-cured plate 100 is first flipped open to expose the second mounting groove 201 and the third mounting groove 301. Install the mounting slot 301, then embed the copper block 400 with the boss 410 facing upwards. This eliminates the need for the boss 410 to be aligned with the first mounting slot 101, reducing the difficulty of embedding the copper block 400. Finally, place the first prepreg plate 100 so that the boss 410 can be accommodated in the first mounting slot 101. The boss 410 protrudes from the top surface of the first prepreg plate 100, and the side of the copper block 400 away from the boss 410 protrudes from the side of the second prepreg plate 300 away from the core plate 200. This prevents the colloid formed after the prepreg melts during subsequent pressing operations from overflowing onto one side of the copper block 400 and the top surface of the boss 410.

[0060] S107. Perform a pressing operation on the plate to be pressed to bond the first semi-cured plate 100, the core plate 200, and the second semi-cured plate 300 together to form a pressed plate. During pressing, the copper foil layer 500 of the first semi-cured plate 100 is in contact with the top surface of the boss 410, and the copper foil layer 500 of the second semi-cured plate 300 is in contact with the side of the copper block 400 away from the boss 410, so as to prevent the glue formed by the melting of the semi-cured plate from overflowing onto the top surface of the boss 410 and the side of the copper block 400 away from the boss 410.

[0061] S108. Apply dry film to both sides of the laminated plate to prepare for subsequent selective etching operations.

[0062] S109. The pressed plate is etched to remove the copper foil layer 500 on the top surface of the boss 410 and the copper foil layer 500 on the side of the copper block 400 facing away from the boss 410.

[0063] In the above embodiments, the method for manufacturing embedded copper blocks in circuit boards uses a single core board 200 and two prepreg boards for lamination. Compared with the production method using two core boards of different thicknesses, this solution is less prone to board warping during lamination. This solution uses an embedding method with the boss 410 facing upwards. Therefore, in the operation of embedding the copper block 400, the first prepreg board 100 is first opened, then the copper block 400 is embedded, and finally the first prepreg board 100 is covered. During this process, it is not necessary to align the boss 410 with the first mounting groove 101 of the first prepreg board 100, thereby reducing the difficulty of embedding the copper block 400 and improving production efficiency. This solution uses a prepreg board instead of resin-coated copper foil (RCC). Compared with RCC, the prepreg board is less prone to wrinkling, which reduces the overall manufacturing cost of the circuit board.

[0064] Combination Figures 2 to 4 As shown, in one embodiment, S105 is executed, which specifically includes the following steps:

[0065] S1051. Drill holes in the first semi-cured plate 100 to give the first semi-cured plate 100 a first rivet hole 102.

[0066] S1052. Drill holes in the core board 200 so that the first semi-cured board 100 has a second rivet hole 202 and a third rivet hole 203.

[0067] S1053. Drilling operation is performed on the second semi-cured plate 300 so that the second semi-cured plate 300 has a fourth rivet hole 302 and a fifth rivet hole 303.

[0068] S1054. The first semi-cured board 100, the core board 200 and the second semi-cured board 300 are stacked, wherein the first rivet hole 102, the second rivet hole 202 and the fourth rivet hole 302 are connected in sequence, and the third rivet hole 203 and the fifth rivet hole 303 are connected.

[0069] S1055. The first semi-cured board 100, the core board 200 and the second semi-cured board 300 are sequentially stacked by two rivets, wherein one rivet is sequentially inserted into the first rivet hole 102, the second rivet hole 202 and the fourth rivet hole 302, and the other rivet is sequentially inserted into the third rivet hole 203 and the fifth rivet hole 303.

[0070] It is understood that the first semi-cured board 100, the core board 200, and the second semi-cured board 300 can be riveted together. Specifically, holes are first drilled in the first semi-cured board 100, the core board 200, and the second semi-cured board 300, and then rivets are inserted so that the first semi-cured board 100, the core board 200, and the second semi-cured board 300 are sequentially stacked and connected. The first semi-cured board 100 and the core board 200 are connected by one rivet, and the core board 200 and the second semi-cured board 300 are connected by two rivets. In this way, when embedding the copper block 400, it is only necessary to open the first semi-cured board 100 to expose the second mounting groove 201 and the third mounting groove 301, then embed the copper block 400, and close the first semi-cured board 100 to complete the embedding operation of the copper block 400, making the embedding of the copper block 400 relatively simple. The two rivets are a first mounting rivet 10a and a second mounting rivet 10b. Furthermore, the first semi-cured plate 100 and the core plate 200 are connected by the first mounting rivet 10a, and the core plate 200 and the second semi-cured plate 300 are connected by the first mounting rivet 10a and the second mounting rivet 10b.

[0071] Furthermore, the length of one of the rivets is greater than the length of the other rivet; specifically, the length of the first mounting rivet 10a is greater than the length of the second mounting rivet 10b. Thus, the first mounting rivet 10a has a certain length to pass through the first rivet hole 102, the second rivet hole 202, and the fourth rivet hole 302, and the second mounting rivet 10b has a certain length to pass through the third rivet hole 203 and the fifth rivet hole 303. Therefore, the first mounting rivet 10a and the second mounting rivet 10b work together to connect the first prepreg 100, the core board 200, and the second prepreg 300 in a sequentially stacked manner.

[0072] In one embodiment, the copper foil layer 500 is a high ductility (HTE) copper foil. In this embodiment, the copper foil layer 500 uses HTE copper foil, which has characteristics such as high temperature stability, high elongation, strong resistance to bottom etching, and excellent mechanical properties. It is widely used in multilayer printed circuit boards (PCBs), high-density interconnect boards (HDI), and other fields. After the copper block 400 is embedded, a lamination operation is performed. During lamination, it is usually at a high temperature (e.g., 200°C). HTE copper foil can maintain excellent elongation at high temperatures and will not oxidize, ensuring the electrical performance of the circuit board in subsequent use.

[0073] In one embodiment, during step S107, the pressing temperature is 200°C-220°C to melt the first semi-cured plate 100 and the second semi-cured plate 300, thereby bonding the first semi-cured plate 100, the core plate 200, and the second semi-cured plate 300 together. Furthermore, controlling the pressing temperature at 200°C-220°C controls the flowability of the first semi-cured plate 100 and the second semi-cured plate 300 after melting, preventing excessive flow that could lead to a lack of adhesive. This allows the first semi-cured plate 100 and the second semi-cured plate 300 to bond together to the sidewall of the copper block 400. Specifically, the first semi-cured plate 100 is bonded to the sidewall of the boss 410 of the copper block 400, and the second semi-cured plate 300 is bonded to the sidewall of the boss 410 of the copper block 400. In a preferred embodiment, the pressing temperature is 220°C. Furthermore, when performing S107, the pressing time is 110 min-120 min, so that the first semi-cured plate 100 and the second semi-cured plate 300 have enough time to melt and adhere the core plate 200 and the copper block 400.

[0074] In one embodiment, the protrusion 410 extends from the top surface of the first semi-cured plate 100 by a height of 10-15 μm. It is understood that the protrusion 410 extending from the top surface of the first semi-cured plate 100 by a height at the micrometer level ensures that the surface of the plate to be pressed is not overly abrupt. Furthermore, because there is a 10-15 μm height distance between the top surface of the protrusion 410 and the top surface of the first semi-cured plate 100, the force exerted by the pressing steel plate on the protrusion 410 during the pressing operation is greater than the force exerted on the first semi-cured plate 100. Additionally, the copper foil layer 500 on one side of the first semi-cured plate 100 abuts against the top surface of the protrusion 410, thus preventing the colloid formed by the fusion of the first semi-cured plate 100 from easily flowing onto the top surface of the protrusion 410.

[0075] Furthermore, the copper block 400 extends 10-15 μm from the side of the second semi-cured plate 300 away from the side of the core plate 200 away from the boss 410. It is understandable that the height of the side of the copper block 400 facing away from the boss 410 extending from the side of the second semi-cured plate 300 facing away from the core plate 200 is at the micrometer level, so that the surface of the plate to be pressed will not be too abrupt. In addition, since there is a height distance of 10-15μm between the side of the copper block 400 facing away from the boss 410 and the side of the second semi-cured plate 300 facing away from the core plate 200, when the plate to be pressed is pressed, the force exerted by the pressing steel plate on the side of the copper block 400 facing away from the boss 410 is greater than the force exerted on the second semi-cured plate 300. Moreover, the copper foil layer 500 on one side of the second semi-cured plate 300 is also in contact with the side of the copper block 400 facing away from the boss 410. As a result, the colloid formed by the fusion of the second semi-cured plate 300 is not easy to flow to the side of the copper block 400 facing away from the boss 410.

[0076] In one embodiment, after executing S109, the following steps are then included:

[0077] The laminated plate is polished so that the top of the boss 410 is flush with the top of the first semi-cured plate 100, and the side of the copper block 400 facing away from the boss 410 is flush with the side of the second semi-cured plate 300 facing away from the core plate 200. A detailed structural diagram is shown below. Figure 5 As shown, Figure 6 This is a partial structural diagram of the circuit board after the polishing operation, to facilitate understanding by those skilled in the art.

[0078] In this embodiment, during the etching operation, the copper foil layer 500 on the first prepreg 100 is covered by a dry film, thus preventing contact with the micro-etching solution. However, the copper foil layer 500 on the top surface of the boss 410 is not covered by a dry film, causing the copper foil layer 500 at that location to be etched by the micro-etching solution. The copper foil layer 500 on the second prepreg 300 is covered by a dry film, thus preventing contact with the micro-etching solution. However, the copper foil layer 500 on the side of the copper block 400 facing away from the boss 410 is not covered by a dry film, causing the copper foil layer 500 at that location to be etched by the micro-etching solution. After the etching operation is completed, the surface of the copper block 400 is exposed. Specifically, the top surface of the boss 410 and the side of the copper block 400 facing away from the boss 410 are exposed. Even though the colloid formed by the melting of the prepreg does not easily flow to the top surface of the boss 410 and the side of the copper block 400 facing away from the boss 410, the top surface of the boss 410 and the first prepreg are still exposed. The transition points between the first and second semi-cured boards 100, and between the copper block 400 facing away from the boss 410 and the second semi-cured board 300, often contain a certain amount of colloid and residual copper foil layer 500. That is, the sidewalls of the protruding part of the boss 410 and the sidewalls of the copper block 400 facing away from the boss 410 contain a certain amount of colloid and residual copper foil layer 500. Therefore, the laminated board needs to be polished to remove the residual colloid and copper foil layer 500 from the protruding part of the boss 410. In addition, the polishing operation is performed to make the top surface of the boss 410 and the side of the copper block 400 facing away from the boss 410 flat until the top surface of the boss 410 is flush with the top surface of the first semi-cured board 100, and the side of the copper block 400 facing away from the boss 410 is flush with the side of the second semi-cured board 300 facing away from the core board 200. This ensures the overall flatness of the circuit board and prevents local structural protrusions. Furthermore, the polishing operation involves polishing the circuit board using ceramic grinding brushes.

[0079] Further, after performing S109 and before polishing the pressed plate, the following steps are included: removing the film from the pressed plate.

[0080] In this embodiment, after the etching operation on the laminated board is completed, the surface of the copper block 400 is exposed. Specifically, the top surface of the boss 410 and the side of the copper block 400 facing away from the boss 410 are exposed. In subsequent operations, OSP (organic solder mask) and immersion gold plating are required. This step requires a film removal process. Otherwise, the residual dry film will prevent the solution from reacting with the copper surface of the copper foil layer 500, resulting in uneven plating, electroplating, or immersion gold plating in subsequent operations, causing poor soldering (such as cold solder joints or solder pad rejection). Therefore, a film removal operation is required on the laminated board to remove the residual dry film on the laminated board with a film removal solution to ensure the progress of subsequent steps. Furthermore, the film removal operation for the laminated board must be carried out before the polishing operation. Specifically, after the micro-etching operation of the circuit board is completed, there are still residual dry films on the circuit board itself. If the polishing operation is carried out directly, a lot of film residue will be generated during polishing. This film residue will contaminate the entire ceramic brush line, affecting the flatness of the circuit board after polishing, increasing the maintenance cost of the ceramic brush line, and thus affecting the production efficiency of the circuit board. Therefore, it is necessary to remove the film from the laminated board first until the dry film on both sides of the laminated board is removed before the subsequent polishing operation can be carried out.

[0081] In one embodiment, after executing S103 and before executing S104, the following steps are included:

[0082] The core board 200 is sanded to give it a rounded corner guide ring 204. The rounded corner guide ring 204 is located on the side of the core board 200 facing away from the second prepreg 300, and surrounds the second mounting groove 201. This creates a guide gap between the rounded corner guide ring 204, the first prepreg 100, and the sidewall of the copper block 400. The specific structure is as follows... Figure 7 and Figure 8 As shown.

[0083] In this embodiment, the solution adopts an embedding method with the boss 410 facing upwards. When executing S106, the first semi-cured plate 100 is flipped open to expose the second mounting slot 201 and the third mounting slot 301. Then, the copper block 400 is embedded with the boss 410 facing upwards. Although this eliminates the need to align the boss 410 with the mounting slot, it is still necessary to align the copper block 400 body with the mounting slot when embedding it, which still presents a certain embedding difficulty. Therefore, the core board 200 has a rounded corner guide ring 204, which surrounds the second mounting slot 201. When the copper block 400 with the boss 410 facing upwards is embedded in the mounting slot, the rounded corner guide ring 204 guides the copper block 400 into the mounting slot, which further reduces the difficulty of embedding the copper block 400 and further improves the overall production efficiency of the circuit board. In addition, by setting the rounded corner guide ring 204, when S107 is executed, the temperature of the first semi-cured board 100 rises to form colloid, and some of the colloid will flow into the guide void until it is filled, thereby achieving the function of filling the gap. It can also further reduce the probability of colloid overflowing the top surface of the boss 410, ensuring the production yield of the circuit board.

[0084] Furthermore, the steps following S101 and S102 are as follows:

[0085] A drilling operation is performed on the copper block 400 to give it a connected vertical channel 401 and an upper horizontal channel 402. During step S105, the opening of the vertical channel 401 faces the first semi-cured plate 100, and the opening of the upper horizontal channel 402 faces the guide cavity. The specific structure is as follows: Figure 7 and Figure 8 As shown.

[0086] In this embodiment, when S107 is executed, the temperature of the first semi-cured board 100 and the second semi-cured board 300 rises until they melt. Since the core board 200 has a rounded corner guide ring 204, the first semi-cured board 100 melts to form a colloid. Some of the colloid flows into the guide void area, and some of the colloid enters the upper transverse channel 402 from the vertical channel 401 until the colloid fills the guide void area, the vertical channel 401 and the upper transverse channel 402. This increases the contact area between the colloid and the copper block 400, better bonding the copper block 400 to the core board 200. This also reduces the amount of colloid overflowing from the side wall of the boss 410, further reducing the probability of colloid overflowing from the top surface of the boss 410, and ensuring the production yield of the circuit board.

[0087] Furthermore, the steps following S101 and S102 are as follows:

[0088] A hole is drilled in the copper block 400 to create a through-hole lower transverse channel 403, wherein the opening of the lower transverse channel 403 faces the second semi-cured plate 300. The specific structure is as follows: Figure 7 and Figure 8 As shown.

[0089] In this embodiment, when S107 is executed, the temperature of the first semi-cured board 100 and the second semi-cured board 300 rises until they melt. Since the copper block 400 has a through-type lower transverse channel 403, part of the colloid formed by the melting of the second semi-cured board 300 passes through the lower transverse channel 403 until it is filled. In addition, the copper foil layer 500 of the second semi-cured board 300 abuts against the side of the copper block 400 away from the copper block 400. This reduces the probability of the colloid formed by the melting of the second semi-cured board 300 overflowing from the sidewall of the copper block 400 to the side of the copper block 400 away from the copper block 400, thus ensuring the production yield of the circuit board.

[0090] This disclosure also provides a circuit board prepared using the circuit board embedded copper block manufacturing method described in any embodiment.

[0091] Compared with the prior art, this disclosure has at least the following advantages:

[0092] 1. The above-mentioned method for manufacturing embedded copper blocks in circuit boards uses a single core board and two semi-cured boards for lamination. Compared with the production method of using two core boards of different thicknesses, this method is less likely to cause board bending during lamination.

[0093] 2. This solution adopts an embedding method with the boss facing upwards. In the process of embedding the copper block, the first semi-cured plate is first opened, then the copper block is embedded, and finally the first semi-cured plate is covered. During this process, it is not necessary to align the boss with the first mounting groove of the first semi-cured plate, thereby reducing the difficulty of embedding the copper block and improving production efficiency.

[0094] 3. This solution uses a prepreg board instead of resin-coated copper foil (RCC). Compared with RCC, the prepreg board is less prone to wrinkling, which reduces the overall manufacturing cost of the circuit board.

[0095] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for manufacturing a buried copper block of a wiring board, characterized by, The method comprises the following steps: S101, acquiring a first prepreg, a core plate, a second prepreg and a copper block, wherein the copper block has a boss, and one side of the first prepreg and one side of the second prepreg are provided with a copper foil layer; S102, performing a hole drilling operation on the first prepreg to form a first installation groove; S103, performing a hole drilling operation on the core plate to form a second installation groove; S104, performing a hole drilling operation on the second prepreg to form a third installation groove; S105, performing a riveting operation on the first prepreg, the core plate and the second prepreg to sequentially arrange the first prepreg, the core plate and the second prepreg, wherein the first installation groove, the second installation groove and the third installation groove are sequentially communicated, the width of the first installation groove is smaller than the width of the second installation groove, and the width of the second installation groove is equal to the width of the third installation groove; S106, turning up the first prepreg and embedding the copper block to form a to-be-pressed plate, wherein the copper block is accommodated in the second installation groove and the third installation groove, and the boss is accommodated in the first installation groove, the boss protrudes from the top surface of the first prepreg, and the side of the copper block away from the boss protrudes from the side of the second prepreg away from the core plate; S107, performing a pressing operation on the to-be-pressed plate to form a pressed plate; S108, pasting dry films on two sides of the pressed plate; S109, performing an etching operation on the pressed plate to remove the copper foil layer on the top surface of the boss and the copper foil layer on the side of the copper block away from the boss.

2. The method of claim 1, wherein the step of forming the copper block is performed by a method selected from the group consisting of a mechanical milling method, a powder metallurgy method, a sintering method, a casting method, and a combination thereof. S105 is performed, and specifically comprises the following steps: S1051, performing a hole drilling operation on the first prepreg to make the first prepreg have a first rivet hole; S1052, performing a hole drilling operation on the core plate to make the first prepreg have a second rivet hole and a third rivet hole; S1053, performing a hole drilling operation on the second prepreg to make the second prepreg have a fourth rivet hole and a fifth rivet hole; S1054, performing a layering operation on the first prepreg, the core plate and the second prepreg, wherein the first rivet hole, the second rivet hole and the fourth rivet hole are sequentially communicated, and the third rivet hole and the fifth rivet hole are communicated; S1055, sequentially layering the first prepreg, the core plate and the second prepreg by two rivets, wherein one of the rivets is sequentially arranged in the first rivet hole, the second rivet hole and the fourth rivet hole, and the other rivet is sequentially arranged in the third rivet hole and the fifth rivet hole.

3. The method of claim 2, wherein the step of forming the copper block comprises the steps of: forming a copper foil on the surface of the circuit board; and laminating the copper foil to the surface of the circuit board. The length of one of the rivets is greater than the length of the other rivet.

4. The method of claim 1, wherein the step of forming the copper block is performed by a method selected from the group consisting of a mechanical milling method, a powder metallurgy method, a sintering method, a casting method, and a combination thereof. The copper foil layer is a high-ductility copper foil.

5. The method of claim 1, wherein the step of forming the copper block is performed by a method selected from the group consisting of a mechanical milling method, a powder metallurgy method, a sintering method, a casting method, and a combination thereof. When S107 is performed, the pressing temperature is 200-220°C.

6. The method of claim 5, wherein the step of forming the copper block is performed by a method comprising: forming a copper foil on the surface of the circuit board; and applying a pressure to the copper foil to embed the copper foil into the circuit board. When S107 is performed, the pressing time is 110-120 min.

7. The method of claim 1, wherein the step of forming the copper block is performed by a method selected from the group consisting of a mechanical milling method, a powder metallurgy method, a sintering method, a casting method, and a combination thereof. The boss protrudes from the top surface of the first prepreg by a height of 10-15 μm. The copper foil layer is a high-ductility copper foil.

8. The method of claim 7, wherein the step of forming the copper block is performed by a method comprising: The copper block has a height of 10-15 μm from the side of the second prepreg plate away from the core plate. ​ 9. The method for manufacturing embedded copper blocks in a circuit board according to claim 1, characterized in that, After performing S109, the following steps are included: The pressed plate is polished so that the top of the protrusion is flush with the top of the first prepreg plate, and the side of the copper block away from the protrusion is flush with the side of the second prepreg plate away from the core plate.

10. A wiring board, characterized by The circuit board embedded copper block is prepared by the method of any one of claims 1-9.

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