Circuit board and circuit board production method

Abstract

The invention relates to a circuit board and a circuit board production method. The circuit board production method comprises the following steps: etching a first core board, a second core board and a third core board to form a first circuit layer, a second circuit layer, a third circuit layer, a fourth circuit layer, a fifth circuit layer and a sixth circuit layer; browning the fourth circuit layer and the fifth circuit layer; pressing and connecting the second core plate and the third core plate; cutting off plate edges after the second core plate and the third core plate are laminated, and drilling mounting holes in the laminated core plates; a heat dissipation block is embedded in the mounting hole; browning the two end faces of the first circuit layer, the second circuit layer, the third circuit layer, the sixth circuit layer and the heat dissipation block; pressing and connecting the first core plate and the second core plate; board edges after the first core board, the second core board and the third core board are laminated are cut off; and flattening the sixth circuit layer. The circuit board and the circuit board production method have the advantages of being good in processing quality and high in qualified rate.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board production, and in particular to a circuit board and a circuit board production method. Background Art

[0002] As electronic products become smaller and smaller, the size of circuit boards is also shrinking, resulting in dense circuits on circuit boards. In addition, the power density of components installed on circuit boards is also increasing, and excessive heat dissipation from circuit boards can easily affect the service life of components and cause component failure.

[0003] Therefore, in order to enhance the heat dissipation capacity of the circuit board, the problem can be solved by directly embedding copper blocks on the circuit board. The specific operation method is to drill installation grooves on the etched core board, and then manually install the copper blocks into the installation grooves and then press the core boards together. However, during high-temperature pressing, the resin flow affects the balance of the copper blocks. After the resin is cured, the copper blocks and the board surface are uneven, and the overflow glue on the copper blocks is difficult to remove. The copper blocks are prone to board explosion, resulting in a low product qualification rate. There are defects such as poor production quality and low qualification rate. Summary of the invention

[0004] Based on this, it is necessary to provide a circuit board and a circuit board production method to address the problems of poor production quality and low pass rate in circuit board production.

[0005] In a first aspect, a circuit board production method is provided, comprising the following steps:

[0006] Etching the first core board, the second core board and the third core board so that the first circuit layer and the second circuit layer are formed on both sides of the first core board, the third circuit layer and the fourth circuit layer are formed on both sides of the second core board, and the fifth circuit layer and the sixth circuit layer are formed on both sides of the third core board;

[0007] Browning the fourth circuit layer and the fifth circuit layer;

[0008] The fourth circuit layer of the second core board and the fifth circuit layer of the third core board are pressed and connected according to the stacking pattern;

[0009] Cut off the edges of the second core plate and the third core plate after pressing together, and drill installation holes in the pressed core plates;

[0010] Implant a heat sink in the mounting hole;

[0011] Browning the first circuit layer, the second circuit layer, the third circuit layer, the sixth circuit layer and two end surfaces of the heat sink;

[0012] The second circuit layer of the first core board and the third circuit layer of the second core board are pressed and connected;

[0013] Cutting off the edges of the first core plate, the second core plate and the third core plate after being pressed together;

[0014] The sixth circuit layer is planarized.

[0015] In one embodiment, when drilling mounting holes in the pressed core board, the following steps are also included:

[0016] Through mounting holes are drilled on the pressed second core board and the third core board, the long side length of the mounting holes is 1-2 mil shorter than the long side length of the heat sink, and the short side length of the mounting holes is 1-2 mil shorter than the short side length of the heat sink.

[0017] In one embodiment, when the sixth circuit layer is flattened, the following steps are included:

[0018] Clean the circuit board;

[0019] Use a grinding machine to grind the surface of the circuit board to remove the overflow glue on the surface;

[0020] Clean the circuit board after grinding;

[0021] Dry the cleaned circuit board to remove moisture from the surface;

[0022] Check the circuit boards after grinding to ensure that their surface quality and performance meet the requirements.

[0023] In one embodiment, when the sixth circuit layer is flattened, the following steps are included:

[0024] Place the circuit board on the workbench of the degumming equipment and ensure that it is fixed and stable;

[0025] Focus the laser or plasma beam on the glue residue on the circuit board to perform ablation and glue removal operations;

[0026] After the debonding is completed, the circuit board is inspected to ensure that the glue residue has been completely removed;

[0027] After debonding is complete, the boards are cleaned and treated to remove any residue and contaminants from the debonding process.

[0028] In one embodiment, when the second core plate and the third core plate are pressed together, the following steps are included:

[0029] The second prepreg is arranged between the fourth circuit layer of the second core board and the fifth circuit layer of the third core board to ensure the alignment and bonding strength between the layers;

[0030] Put the stacked materials into a press, and heat and pressurize them to tightly combine the layers of materials into a whole;

[0031] The pressed circuit board is cooled.

[0032] In one embodiment, when the heat sink is implanted in the mounting hole, the following steps are included:

[0033] Use an automatic press-in machine to press the heat sink into the mounting hole from one side of the third circuit layer;

[0034] After the heat sink is pressed into place, the circuit board is checked to ensure that the end surface of the heat sink is aligned with the sixth circuit layer.

[0035] In one embodiment, after etching the first core board, the second core board and the third core board, the following steps are further included:

[0036] Scanning the first core plate, the second core plate and the third core plate to obtain surface images of the first core plate, the second core plate and the third core plate;

[0037] Process and analyze the acquired images to identify possible defects and problems;

[0038] According to the result of image processing, the defects are judged and classified, and qualified first core boards, second core boards and third core boards are screened out.

[0039] In one embodiment, after the sixth circuit layer is flattened, the following steps are further included:

[0040] Drill via holes into the circuit board from the first circuit layer.

[0041] In a second aspect, a circuit board is provided, which utilizes the circuit board production method described in any of the above embodiments, comprising a first core board, a second core board, a third core board and a heat sink, wherein a first circuit layer and a second circuit layer are respectively provided on both sides of the first core board, a third circuit layer and a fourth circuit layer are respectively provided on both sides of the second core board, a fifth circuit layer and a sixth circuit layer are respectively provided on both sides of the third core board, the first core board and the second core board are cured and connected by a first semi-cured sheet, the second core board and the third core board are cured and connected by a second semi-cured sheet, the circuit board is provided with mounting holes, the mounting holes are provided on the second core board and the third core board, and the heat sink is installed in the mounting holes.

[0042] In one of the embodiments, the flatness of the heat sink and the sixth circuit layer is less than 25 um.

[0043] The above-mentioned circuit board and circuit board production method are achieved by etching the circuit layers on the first core board, the second core board and the third core board respectively, and then browning the fourth circuit layer of the second core board and the fifth circuit layer of the third core board first, and then drilling through mounting holes after curing and connecting the fourth circuit layer and the fifth circuit layer together, and installing the heat sink into the mounting holes. Since the mounting holes in the second core board and the third core board are through holes, the heat sink can be installed from one side of the second core board, and then the end face of the heat sink is installed flush with the sixth circuit layer of the third core board, and finally, after browning the other circuit layers, the first core board is covered on the second core board for curing and connection. The present application first processes the through mounting holes on the second core board and the third core board, and then installs the heat sink in the through mounting holes, so that it is easy to align the heat sink with the sixth circuit layer, improve the flatness of the heat sink, and the heat sink can be browned together when the third circuit layer is browned, thereby strengthening the curing effect of the second core board and the first core board, reducing the probability of board explosion, and having the advantages of good processing quality and high qualified rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the process of producing a circuit board according to an embodiment of the present application.

[0045] Figure 2 This is a schematic diagram of the structure of the circuit board described in the embodiment of the present application.

[0046] Figure Number:

[0047] 100, first core board; 101, first circuit layer; 102, second circuit layer;

[0048] 200, second core board; 201, third circuit layer; 202, fourth circuit layer;

[0049] 300, third core board; 301, fifth circuit layer; 302, sixth circuit layer;

[0050] 410, mounting hole; 420, via hole;

[0051] 500, heat sink;

[0052] 610, a first prepreg; 620, a second prepreg. DETAILED DESCRIPTION

[0053] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0054] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0055] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0056] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0057] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0058] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0059] See also Figure 1 and Figure 2 , Figure 1 The figure shows a schematic flow chart of a circuit board production method in an embodiment of the present application. Figure 2 A schematic diagram of the structure of a circuit board produced by the circuit board production method is shown, and the circuit board production method comprises the following steps:

[0060] S100: Clean the first core board 100, the second core board 200 and the third core board 300 to remove impurities such as oil, dust and the like on the surface; etch the first core board 100, the second core board 200 and the third core board 300 so that the first circuit layer 101 and the second circuit layer 102 are formed on both sides of the first core board 100, the third circuit layer 201 and the fourth circuit layer 202 are formed on both sides of the second core board 200, and the fifth circuit layer 301 and the sixth circuit layer 302 are formed on both sides of the third core board 300;

[0061] S200: browning the fourth circuit layer 202 and the fifth circuit layer 301;

[0062] S300: Press-connecting the fourth circuit layer 202 of the second core board 200 and the fifth circuit layer 301 of the third core board 300 according to the stacking pattern;

[0063] S400: cutting off the edges of the second core plate 200 and the third core plate 300 after being pressed together, and drilling mounting holes 410 in the pressed core plates;

[0064] S500: implanting a heat sink 500 into the mounting hole 410, wherein the heat sink 500 is preferably a copper block;

[0065] S600: browning the first circuit layer 101, the second circuit layer 102, the third circuit layer 201, the sixth circuit layer 302 and two end surfaces of the heat sink 500;

[0066] S700: Press-connecting the second circuit layer 102 of the first core board 100 and the third circuit layer 201 of the second core board 200;

[0067] S800: cutting off the edges of the first core plate 100, the second core plate 200 and the third core plate 300 after being pressed together;

[0068] S900: performing a planarization process on the sixth circuit layer 302 .

[0069] The circuit board production method described in the embodiment of the present application is performed by etching the first circuit layer 101 and the second circuit layer 102 from the two surfaces of the first core board 100, etching the third circuit layer 201 and the fourth circuit layer 202 from the two surfaces of the second core board 200, and etching the fifth circuit layer 301 and the sixth circuit layer 302 from the two surfaces of the third core board 300, and then browning the fourth circuit layer 202 of the second core board 200 and the fifth circuit layer 301 of the third core board 300 to increase the surface roughness and bonding strength. Then, the fourth circuit layer 202 and the fifth circuit layer 301 are cured and connected together through the second semi-cured sheet 620, and then a through mounting hole 410 is drilled, and the heat sink 500 is installed into the mounting hole 410. Since the mounting hole 410 in the second core board 200 and the third core board 300 is a through hole, the heat sink 500 can be installed from one side of the second core board 200, so that the end face of the heat sink 500 is conveniently installed flush with the sixth circuit layer 302 of the third core board 300. Finally, after the two end faces of the first circuit layer 101, the second circuit layer 102, the third circuit layer 201, the sixth circuit layer 302 and the heat sink 500 are browned, the first core board 100 is covered on the second core board 200 and cured and connected.

[0070] The circuit board production method described in the embodiment of the present application is to first process the through mounting holes 410 on the second core board 200 and the third core board 300, and then install the heat sink 500 in the through mounting holes 410. Since the heat sink 500 can be inserted from the side of the second core board 200, it is easy to align the heat sink 500 with the sixth circuit layer 302, thereby improving the flatness of the heat sink, so that the flatness of the heat sink 500 and the sixth circuit layer 302 is less than 25um. Moreover, when the third circuit layer 201 is browned, the heat sink 500 can be browned together, thereby strengthening the curing connection effect of the second core board 200 and the first core board 100, reducing the probability of board explosion, and having the advantages of good processing quality and high qualified rate.

[0071] In some embodiments, in step S100, after etching the first core plate 100, the second core plate 200 and the third core plate 300, the following steps are further included:

[0072] Scanning the first core plate 100 , the second core plate 200 , and the third core plate 300 to obtain surface images of the first core plate 100 , the second core plate 200 , and the third core plate 300 ;

[0073] Process and analyze the collected images to identify possible defects and problems, such as short circuit, open circuit, lack of welding, etc.

[0074] According to the result of image processing, the defects are judged and classified, and qualified first core boards 100 , second core boards 200 , and third core boards 300 are screened out.

[0075] In this embodiment, after the first core board 100, the second core board 200 and the third core board 300 are etched, each core board is subjected to automatic optical inspection. The automatic optical inspection system is a device technology that uses optical principles to automatically detect the surface features of the core board. It identifies various defects on the core board through optical imaging and image analysis and processing, and can automatically screen out qualified core boards. It has the advantages of high processing efficiency and stable quality.

[0076] In an optional embodiment, in step S200, the fourth circuit layer 202 and the fifth circuit layer 301 are cleaned to remove impurities such as oil and dust on the surface, and the fourth circuit layer 202 and the fifth circuit layer 301 are placed in a browning liquid to form a layer of brown oxide film on the surface of the fourth circuit layer 202 and the fifth circuit layer 301 through a chemical reaction to increase the surface roughness and bonding force of the fourth circuit layer 202 and the fifth circuit layer 301. The browned circuit board is cleaned to remove the browning liquid and impurities on the surface. The cleaned circuit board is dried to remove moisture from the surface. Similarly, in step S600, the first circuit layer 101, the second circuit layer 102, the third circuit layer 201, the sixth circuit layer 302 and the two end faces of the heat sink 500 are browned using the above method.

[0077] In an optional embodiment, in step S300, when the second core plate 200 and the third core plate 300 are pressed together, the following steps are included:

[0078] The second prepreg 620 is disposed between the fourth circuit layer 202 of the second core board 200 and the fifth circuit layer 301 of the third core board 300 to ensure the alignment and bonding force between the layers;

[0079] Put the stacked materials into a press, and heat and pressurize them to tightly combine the layers of materials into a whole;

[0080] The pressed circuit board is cooled.

[0081] In this embodiment, a second semi-cured sheet 620 is placed between the second core board 200 and the third core board 300, and the fourth circuit layer 202 and the fifth circuit layer 301 are arranged toward the second semi-cured sheet 620. Then, the second core board 200 and the third core board 300 are connected as a whole by heating and pressurizing. The pressed circuit board is inspected to ensure that its quality and performance meet the requirements.

[0082] In an optional embodiment, in step S400, when drilling the mounting hole 410 in the pressed core plate, the following steps are also included:

[0083] A through mounting hole 410 is drilled on the pressed second core board 200 and the third core board 300 , the long side length of the mounting hole 410 is 1-2 mil shorter than the long side length of the heat sink 500 , and the short side length of the mounting hole 410 is 1-2 mil shorter than the short side length of the heat sink 500 .

[0084] In this embodiment, the long side length and the short side length of the mounting hole 410 are both smaller than the long side length and the short side length of the heat sink 500, so that the heat sink 500 can achieve an interference fit in the mounting hole 410. The heat sink 500 can be firmly embedded in the mounting hole 410, so that the heat sink 500 will not shift during the subsequent pressing process, ensuring that the heat sink 500 is flush with the sixth circuit layer 302, thereby ensuring better flatness of the circuit board surface and improving processing quality and qualified rate.

[0085] In other embodiments, if the mounting hole 410 and the heat sink 500 are circular, the diameter of the mounting hole 410 is 1-2 mil smaller than the diameter of the heat sink 500. Similarly, the circular heat sink 500 can also be firmly mounted in the mounting hole 410 by interference fit, thereby improving the flatness of the circuit board surface.

[0086] In an optional embodiment, in step S500, when the heat sink 500 is implanted in the mounting hole 410, the following steps are included:

[0087] Use an automatic press-in machine to press the heat sink 500 into the mounting hole 410 from one side of the third circuit layer 201;

[0088] The circuit board after the heat sink 500 is pressed in is inspected to ensure that the end surface of the heat sink 500 is aligned with the sixth circuit layer 302 .

[0089] The embodiment of the present application can utilize an automatic pressing machine to press the heat sink block 500 into the mounting hole 410, thereby realizing automated processing. Moreover, the automatic pressing machine presses from one side of the third circuit layer 201, thereby allowing the heat sink block 500 to be quickly aligned to the sixth circuit layer 302 on the other side. Furthermore, the heat sink block 500 and the sixth circuit layer 302 have better flatness, thereby having the advantages of high processing efficiency and good processing quality.

[0090] In an optional embodiment, in step S700, the second circuit layer 102 of the first core board 100 and the third circuit layer 201 of the second core board 200 are pressed and connected, including the following steps:

[0091] The first prepreg 610 is disposed between the second circuit layer 102 of the first core board 100 and the third circuit layer 201 of the second core board 200 to ensure the alignment and bonding force between the layers;

[0092] Put the stacked materials into a press, and heat and pressurize them to tightly combine the layers of materials into a whole;

[0093] The pressed circuit board is cooled.

[0094] In this embodiment, a first semi-cured sheet 610 is placed between the first core board 100 and the second core board 200, and the second circuit layer 102 and the third circuit layer 201 are arranged toward the first semi-cured sheet 610. Then, the first core board 100 and the second core board 200 are connected as a whole by heating and pressurizing. The pressed circuit board is inspected to ensure that its quality and performance meet the requirements.

[0095] In an optional embodiment, in step S900, the flattening process for the sixth circuit layer 302 includes the following steps:

[0096] Clean the circuit board to remove oil, dust and other impurities on the surface;

[0097] Use a grinding machine to grind the surface of the circuit board to remove the overflow glue on the surface of the heat sink 500 and the third core board 300;

[0098] Clean the circuit board after grinding to remove the grinding debris and impurities on the surface;

[0099] Dry the cleaned circuit board to remove moisture from the surface;

[0100] Check the circuit boards after grinding to ensure that their surface quality and performance meet the requirements.

[0101] In the embodiment of the present application, the surface of the circuit board is polished by a polishing machine, so that the glue overflowing from the gap of the heat sink 500 during curing is polished off, so that the surface of the circuit board meets the flatness requirement. Moreover, the overflowing glue can be removed more quickly by polishing, which has the advantage of improving efficiency.

[0102] In other embodiments, in step S900, the sixth circuit layer 302 is flattened, including the following steps:

[0103] Place the circuit board on the workbench of the degumming equipment and ensure that it is fixed and stable;

[0104] Focus the laser or plasma beam on the glue residue on the circuit board to perform ablation and glue removal. During the operation, it is necessary to control the time and temperature of glue removal to avoid damage to the circuit board.

[0105] After the degumming is completed, the circuit board is inspected to ensure that the glue residue has been completely removed. If any residual glue residue is found, the degumming operation can be performed again until the requirements are met;

[0106] After the degumming is completed, the circuit board is cleaned and treated to remove the residues and contaminants generated during the degumming process. It can be cleaned with detergent and pure water, and then blown dry with nitrogen;

[0107] Carry out quality inspection on the circuit board after degumming, including appearance inspection, electrical performance test, etc., to ensure that it meets the quality requirements.

[0108] The embodiment of the present application can also remove the overflow glue at the heat sink 500 by ablation. According to the material of the circuit board and the properties of the glue residue, a suitable ablation debonding process is selected, such as laser ablation, plasma debonding, etc. According to the selected debonding process, the parameters of the equipment are adjusted, such as laser power, scanning speed, plasma gas flow, etc., to ensure the best debonding effect.

[0109] In an optional embodiment, in step S900, after the sixth circuit layer 302 is flattened, the following steps are further included:

[0110] A via hole 420 is drilled into the circuit board from the first circuit layer 101 .

[0111] In this embodiment, by drilling a via hole 420 on the first circuit layer 101, the circuits of different layers are connected together, so that the current can flow between the layers, so that the circuit board can realize complex circuit functions. First, the initial hole of the via hole is drilled on the circuit board using a CNC drilling machine. During the drilling process, drilling stains will be generated on the hole wall, affecting the adhesion and conductivity of the copper layer. Therefore, it is necessary to remove the drilling stains by chemical methods, and perform chemical copper deposition on the hole wall so that a conductive copper layer is initially formed on the hole wall. On the basis of chemical copper deposition, the copper layer is thickened on the hole wall by an electroplating process to improve the conductivity and mechanical strength of the via hole. In order to prevent the copper layer from oxidizing and improve the welding performance, it is also necessary to properly treat the surface of the via hole, such as tin plating, gold plating, tin spraying, etc.

[0112] On the other hand, the present application also provides a circuit board, using the circuit board production method described in any of the above embodiments, such as Figure 2As shown, the circuit board includes a first core board 100, a second core board 200, a third core board 300 and a heat sink 500. The first core board 100 is provided with a first circuit layer 101 and a second circuit layer 102 on both sides, the second core board 200 is provided with a third circuit layer 201 and a fourth circuit layer 202 on both sides, and the third core board 300 is provided with a fifth circuit layer 301 and a sixth circuit layer 302 on both sides. The first core board 100 and the second core board 200 are cured and connected by a first semi-cured sheet 610, and the second core board 200 and the third core board 300 are cured and connected by a second semi-cured sheet 620. The circuit board is provided with a mounting hole 410, and the mounting hole 410 is set on the second core board 200 and the third core board 300, and the heat sink 500 is installed in the mounting hole 410.

[0113] Specifically, the flatness of the heat sink 500 and the sixth circuit layer 302 processed by the circuit board production method described in any of the above embodiments is less than 25 um.

[0114] In the circuit board described in the embodiment of the present application, the heat sink 500 is embedded in the mounting holes 410 of the second core board 200 and the third core board 300 in a semi-buried manner. During processing, the second core board 200 and the third core board 300 are first cured and connected, and then the through mounting holes 410 are drilled on the second core board 200 and the third core board 300, and then the heat sink 500 is pressed in from one side of the second core board 200, so that the heat sink 500 is flush with the sixth circuit layer 302 of the third core board 300 on the side facing the third core board 300, thereby improving the flatness between the heat sink 500 and the sixth circuit layer 302, so that the flatness of the heat sink 500 and the sixth circuit layer 302 is less than 25um. Finally, the first core board 100 is covered and cured on the second core board 200 to form a semi-buried structure of the heat sink 500. Moreover, when the third circuit layer 201 is browned, the heat sink 500 can be browned together, thereby strengthening the curing connection effect between the second core board 200 and the first core board 100, reducing the probability of board explosion, and having the advantages of good processing quality and high pass rate.

[0115] The circuit board and the circuit board production method described in the embodiments of the present application have the following beneficial effects:

[0116] 1. By first processing the through mounting holes 410 on the second core board 200 and the third core board 300, and then installing the heat sink 500 in the through mounting holes 410, since it can be inserted from the side of the second core board 200, it is easy to align the heat sink 500 with the sixth circuit layer 302, thereby improving the flatness of the heat sink, and making the flatness of the heat sink 500 and the sixth circuit layer 302 less than 25um. In addition, when the third circuit layer 201 is browned, the heat sink 500 can be browned together, thereby strengthening the curing connection effect of the second core board 200 and the first core board 100, reducing the probability of board explosion, and having the advantages of good processing quality and high qualified rate.

[0117] 2. The heat sink 500 is pressed into the mounting hole 410 using an automatic press machine, which can realize automated processing. The automatic press machine presses from one side of the third circuit layer 201, so that the heat sink 500 is quickly aligned to the sixth circuit layer 302 on the other side. In addition, the heat sink 500 and the sixth circuit layer 302 have better flatness, which has the advantages of high processing efficiency and good processing quality.

[0118] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A circuit board production method, characterized in that: The steps include: The first core board (100), the second core board (200) and the third core board (300) are etched so that the first circuit layer (101) and the second circuit layer (102) are formed on both sides of the first core board (100), the third circuit layer (201) and the fourth circuit layer (202) are formed on both sides of the second core board (200), and the fifth circuit layer (301) and the sixth circuit layer (302) are formed on both sides of the third core board (300); browning the fourth circuit layer (202) and the fifth circuit layer (301); The fourth circuit layer (202) of the second core board (200) and the fifth circuit layer (301) of the third core board (300) are pressed and connected according to the stacking pattern; Cutting off the edges of the pressed second core plate (200) and the third core plate (300), and drilling mounting holes (410) in the pressed core plates; Implanting a heat sink (500) in the mounting hole (410); Browning the two end surfaces of the first circuit layer (101), the second circuit layer (102), the third circuit layer (201), the sixth circuit layer (302) and the heat sink (500); The second circuit layer (102) of the first core board (100) and the third circuit layer (201) of the second core board (200) are pressed and connected; Cutting off the edges of the first core plate (100), the second core plate (200) and the third core plate (300) after being pressed together; The sixth circuit layer (302) is flattened.

2. The circuit board production method according to claim 1, characterized in that: When drilling the mounting holes (410) in the pressed core plate, the following steps are also included: A through mounting hole (410) is drilled on the pressed second core board (200) and the third core board (300), the long side length of the mounting hole (410) being 1-2 mils shorter than the long side length of the heat sink (500), and the short side length of the mounting hole (410) being 1-2 mils shorter than the short side length of the heat sink (500).

3. The circuit board production method according to claim 1, characterized in that: When the sixth circuit layer (302) is flattened, the following steps are included: Clean the circuit board; Use a grinding machine to grind the surface of the circuit board to remove the overflow glue on the surface; Clean the circuit board after grinding; Dry the cleaned circuit board to remove moisture from the surface; Check the circuit boards after grinding to ensure that their surface quality and performance meet the requirements.

4. The circuit board production method according to claim 1, characterized in that: When the sixth circuit layer (302) is flattened, the following steps are included: Place the circuit board on the workbench of the degumming equipment and ensure that it is fixed and stable; Focus the laser or plasma beam on the glue residue on the circuit board to perform ablation and glue removal operations; After the debonding is completed, the circuit board is inspected to ensure that the glue residue has been completely removed; After debonding is complete, the boards are cleaned and treated to remove any residue and contaminants from the debonding process.

5. The circuit board production method according to claim 1, characterized in that: When the second core plate (200) and the third core plate (300) are pressed together, the following steps are included: The second prepreg (620) is arranged between the fourth circuit layer (202) of the second core board (200) and the fifth circuit layer (301) of the third core board (300) to ensure the alignment and bonding force between the layers; Put the stacked materials into a press, and heat and pressurize them to tightly combine the layers of materials into a whole; The pressed circuit board is cooled.

6. The circuit board production method according to claim 1, characterized in that: When the heat sink (500) is implanted in the mounting hole (410), the following steps are included: Using an automatic press-in machine to press the heat sink (500) into the mounting hole (410) from one side of the third circuit layer (201); The circuit board after being pressed into the heat sink (500) is inspected to ensure that the end surface of the heat sink (500) is aligned flatly with the sixth circuit layer (302).

7. The circuit board production method according to claim 1, characterized in that: After etching the first core plate (100), the second core plate (200) and the third core plate (300), the following steps are also included: Scanning the first core plate (100), the second core plate (200) and the third core plate (300) to obtain surface images of the first core plate (100), the second core plate (200) and the third core plate (300); Process and analyze the acquired images to identify possible defects and problems; According to the image processing results, defects are judged and classified, and qualified first core boards (100), second core boards (200), and third core boards (300) are screened out.

8. The circuit board production method according to claim 1, characterized in that: After the sixth circuit layer (302) is flattened, the following steps are further included: A via hole (420) is drilled into the circuit board from the first circuit layer (101).

9. A circuit board, using the circuit board production method according to any one of claims 1 to 8, characterized in that: The invention comprises a first core board (100), a second core board (200), a third core board (300) and a heat sink (500); the first core board (100) is provided with a first circuit layer (101) and a second circuit layer (102) on both sides; the second core board (200) is provided with a third circuit layer (201) and a fourth circuit layer (202) on both sides; the third core board (300) is provided with a fifth circuit layer (301) and a sixth circuit layer (302) on both sides; the first core board (100) and the second core board (200) are connected by curing through a first prepreg (610); the second core board (200) and the third core board (300) are connected by curing through a second prepreg (620); the circuit board is provided with a mounting hole (410); the mounting hole (410) is provided on the second core board (200) and the third core board (300); and the heat sink (500) is mounted on the mounting hole (410).

10. The circuit board according to claim 9, characterized in that: The flatness of the heat dissipation block (500) and the sixth circuit layer (302) is less than 25 um.

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