Manufacturing method of multilayer circuit board

Abstract

The invention relates to a manufacturing method of a multi-layer circuit board. The manufacturing method comprises the following steps: respectively manufacturing a first laminated board and a first layer board; a through mounting groove is formed in the first pressing plate; putting the copper particles into the mounting groove; the first layer plate is pressed to the first pressing plate, and the first layer plate covers the mounting groove to form a multi-layer plate; according to the thickness of the multi-layer board, through holes are formed in the multi-layer board in a segmented drilling mode, and the through holes penetrate through the first-layer board and the copper particles. According to the manufacturing method of the multi-layer circuit board, the through holes in the positions where the copper particles are buried are formed in a segmented drilling mode, so that the continuous drilling depth of a drill bit can be reduced in the segmented drilling mode, the impact force borne by the drill bit when the hole positions are formed in the positions where the copper particles are buried is effectively relieved, and the quality of the multi-layer circuit board is improved. And the heat dissipation capability of the drill bit is improved, so that the problems of drill bit abrasion and needle breakage during drilling on the copper particles can be avoided.

Description

Technical Field

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

[0002] During the use of the circuit board, many electronic components will be loaded. The performance of the electronic components will decline and be damaged when the temperature is too high. The overheating failure of the electronic components will affect the stability and reliability of the entire system. Therefore, the heat dissipation problem has always been the focus of attention in the production of circuit boards.

[0003] In the related art, an effective solution to the heat dissipation problem of circuit boards is to embed copper particles in the circuit boards. When the circuit boards generate heat, the copper particles can quickly transfer the heat to other parts to ensure the normal operation of the circuit boards. However, in the conventional circuit board manufacturing process, after the copper particles are embedded in the circuit boards, it is often necessary to drill holes at the locations where the copper particles are embedded. At this time, the drill tip will be subjected to a large external force impact, which is easy to cause problems such as drill tip wear and broken needles. Summary of the invention

[0004] Based on this, it is necessary to provide a method for manufacturing a multilayer circuit board to solve the problems of drill tip wear and needle breakage when drilling holes at the location of buried copper particles.

[0005] The technical solution is as follows:

[0006] A method for manufacturing a multilayer circuit board, comprising:

[0007] respectively manufacturing a first pressed board and a first layer board;

[0008] A penetrating installation groove is provided on the first pressing plate;

[0009] Place the copper pellets into the mounting slot;

[0010] Laminating the first layer board to the first laminating board, wherein the first layer board covers the mounting groove, to form a multilayer board;

[0011] According to the thickness of the multilayer board, a through hole is opened on the multilayer board by using a segmented drilling method, and the through hole penetrates the first layer board and the copper particles.

[0012] In the above-mentioned method for manufacturing a multi-layer circuit board, after the copper particles are buried in the mounting grooves of the first pressing plate and the first layer of the board is pressed onto the first pressing plate, the required through holes are opened at the positions where the copper particles are buried by means of segmented drilling. In this way, the depth of each continuous drilling of the drill bit can be reduced by means of segmented drilling, thereby reducing the impact force on the drill bit when opening holes at the positions where the copper particles are buried, and improving the heat dissipation capacity of the drill bit, thereby avoiding wear of the drill bit and even broken needles. In addition, the problem of poor chip removal during the drilling process can be alleviated by means of a multi-step drilling process of cutting and returning the knife, which greatly reduces the probability of knife breakage during the processing process and ensures a good hole shape. Compared with the existing one-step drilling method, this drilling method can reduce the probability of drill bit wear and broken needles, reduce the scrap rate, and improve the drilling quality.

[0013] The technical solution is further described below:

[0014] In one embodiment, in the step of opening a through hole in the multilayer board by drilling in sections according to the thickness of the multilayer board, wherein the through hole penetrates the first layer board and the copper particles, the steps include:

[0015] Opening a first hole section on the first layer board by a drill, the first hole section penetrates to the surface of the copper particles close to the first layer board, and retracting the drill to a first set distance, the first set distance being less than the depth of the first hole section;

[0016] The drill bit uses a multi-stage drilling method to form a penetrating second hole segment on the copper particle. After each segment of drilling of the copper particle is completed, the drill bit retreats to a second set distance, and the second set distance is less than the drilling depth of the corresponding drilling process on the copper particle.

[0017] In one embodiment, the step of forming a penetrating second hole segment on the copper particle by drilling with a multi-segment drill comprises:

[0018] Drilling the second hole section in equal sections or in unequal sections; and / or,

[0019] The drilling process of the second hole section is divided into three stages.

[0020] In one embodiment, the step of opening a first hole section on the first layer board by a drill, the first hole section penetrates to the surface of the copper particles close to the first layer board, and the drill is retracted to a first set distance, wherein the first set distance is less than the depth of the first hole section, includes the following steps:

[0021] The drill bit forms the first hole segment by drilling in multiple steps. After each drilling on the first layer of the board is completed, the drill bit retreats a predetermined distance, and the predetermined distance is less than the drilling depth of the corresponding drilling process on the first layer of the board.

[0022] In one embodiment, after the step of drilling a through hole in the multilayer board by segmented drilling according to the thickness of the multilayer board, wherein the through hole penetrates the first layer board and the copper particles, the following steps are also included:

[0023] A communication metal layer is formed in the hole wall of the through hole, so that the communication metal layer is connected to the copper grain.

[0024] In one embodiment, before the step of providing a through installation groove on the first pressing plate, the following steps are also included:

[0025] According to the thickness of the first pressed plate, obtaining the controlled depth;

[0026] Opening a depth-controlled groove on the first surface of the first pressing plate according to the depth-controlled depth;

[0027] A first positioning hole is opened at the bottom of the depth-controlling groove by a punching machine, and the first positioning hole passes through the first pressing plate.

[0028] In one embodiment, before the step of laminating the first layer board to the first laminating board so that the first layer board covers the mounting groove to form a multilayer board, the following steps are also included:

[0029] Opening a second positioning hole on the first layer of board by the punching machine;

[0030] placing the first pressing plate on the fusion machine through the first positioning hole;

[0031] A first prepreg is arranged on the second surface of the first pressing plate, and the first surface is arranged opposite to the second surface;

[0032] The first layer plate is placed on the fusion machine through the second positioning hole, and the first layer plate covers the side of the first prepreg facing away from the first pressing plate;

[0033] The first pressed board, the first prepreg and the first layer board are fused by the fusion machine.

[0034] In one embodiment, after the step of laminating the first layer board to the first laminating board, wherein the first layer board covers the mounting groove, to form a multilayer board, the following steps are further included:

[0035] removing burrs from the periphery of the multilayer board; and / or,

[0036] Grinding the surface of the multilayer board to roughen the surface of the multilayer board; and / or,

[0037] Excess copper material on the surface of the multilayer board is removed so that the thickness of the multilayer board reaches a preset thickness.

[0038] In one embodiment, the step of making the first pressed board specifically includes the following steps:

[0039] Make the second layer board and the third layer board respectively;

[0040] Disposing a second prepreg between the second layer and the third layer;

[0041] The second layer board, the second prepreg sheet and the third layer board are pressed together at a preset temperature and a preset pressure to form the first pressed board.

[0042] In one embodiment, the steps of making the first layer board, making the second layer board and making the third layer board all include the following steps:

[0043] Divide bulk materials into substrates of preset sizes;

[0044] Manufacturing circuit layers on both sides of the substrate;

[0045] The circuit layer is roughened. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a simplified structural diagram of a multilayer circuit board during the manufacturing process of an embodiment.

[0047] Figure 2 The figure is a schematic structural diagram of a multilayer circuit board according to an embodiment.

[0048] Figure 3 The present invention is a flow chart of a method for manufacturing a multilayer circuit board according to an embodiment of the present invention.

[0049] Figure 4 The present invention is a flow chart of a method for manufacturing a multilayer circuit board according to another embodiment.

[0050] Figure 5 This is a schematic structural diagram of a first pressing plate having a depth-controlled groove in one embodiment.

[0051] Figure 6 It is a structural schematic diagram of a first positioning hole formed on a first pressing plate according to an embodiment.

[0052] Figure 7 The figure is a schematic diagram of the structure of the first layer board, the second layer board and the third layer board of an embodiment.

[0053] Description of reference numerals:

[0054] 101, substrate; 102, circuit layer; 11, first pressing plate; 103, depth control groove; 104, first positioning hole; 111, second layer plate; 112, third layer plate; 113, second prepreg; 12, first layer plate; 13, first prepreg; 14, copper particles; 15, through hole; 151, first hole section; 152, second hole section. DETAILED DESCRIPTION

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] Specifically, in the conventional circuit board manufacturing process, copper particles are usually buried in the circuit board first, and then holes are drilled at the buried copper particle locations. However, due to the high hardness of copper particles, when the board thickness at the drilling location is large and a one-stage drilling method is used to drill holes at the buried copper particle locations, the drill tool will be subjected to a large external force impact, which can easily cause problems such as drill tool wear and broken needles.

[0062] Based on this, an embodiment of the present application provides a method for manufacturing a multilayer circuit board. Specifically, referring to Figure 1 , Figure 2 and Figure 3 A method for manufacturing a multilayer circuit board according to an embodiment of the present invention comprises the following steps:

[0063] S1: manufacturing a first pressing plate 11 and a first layer plate 12 respectively;

[0064] Specifically, the first laminated board 11 may be formed by laminating a plurality of circuit boards, and the first layer board 12 may be a single circuit board or may be formed by laminating a plurality of circuit boards.

[0065] S2: a through-going mounting groove is provided on the first pressing plate 11;

[0066] For example, in one embodiment, the mounting groove can be formed by forming a groove on the first pressing plate 11. In other embodiments, the mounting groove can also be formed in other ways. Furthermore, the size and shape of the mounting groove are consistent with the size and shape of the copper particles 14 to be installed.

[0067] S3: placing the copper particles 14 into the installation slot;

[0068] S4: Pressing the first layer board 12 onto the first pressing board 11, the first layer board 12 covers the mounting groove to form a multi-layer board;

[0069] S5: According to the thickness of the multilayer board, a through hole 15 is opened on the multilayer board by using a segmented drilling method, and the through hole 15 passes through the first layer board 12 and the copper particles 14.

[0070] Specifically, the through hole 15 can be divided into multiple sections, such as two, three, four or more sections, according to the thickness of the multilayer board, so as to form the through hole 15 by means of segmented drilling. When the through hole 15 is formed at the position of the buried copper particles 14 by means of multi-segmented drilling, the depth of each continuous drilling of the drill bit is small, so that the impact force and wear of the drill bit can be reduced, which is conducive to improving the situation of the drill bit breaking.

[0071] In the above-mentioned method for manufacturing a multi-layer circuit board, after the copper particles 14 are buried in the mounting grooves of the first pressing plate 11 and the first layer 12 is pressed onto the first pressing plate 11, the required through holes 15 are opened at the positions where the copper particles 14 are buried by means of segmented drilling. In this way, the depth of each continuous drilling of the drill bit can be reduced by means of segmented drilling, thereby reducing the impact force on the drill bit when opening holes at the positions where the copper particles 14 are buried, and improving the heat dissipation capacity of the drill bit, thereby avoiding wear of the drill bit and even broken needles. In addition, the problem of poor chip removal during the drilling process can be alleviated by means of a multi-step drilling process of cutting and returning the knife, which greatly reduces the probability of knife breakage during the processing process and ensures a good hole shape. Compared with the existing one-step drilling method, this drilling method can reduce the probability of drill bit wear and broken needles, reduce the scrap rate, and improve the drilling quality.

[0072] In one embodiment, Figure 4 As shown, step S5: according to the thickness of the multilayer board, a through hole 15 is opened on the multilayer board by a segmented drilling method, and the through hole 15 penetrates the first layer board 12 and the copper particles 14, including the following steps:

[0073] S51: Drilling a first hole section 151 on the first board 12 through a drill, the first hole section 151 penetrates to the surface of the copper particles 14 close to the first board 12, and retracting the drill to a first set distance, the first set distance being less than the depth of the first hole section 151;

[0074] Specifically, the drilling method of the first hole segment 151 is selected according to the thickness from the surface of the first layer of board 12 away from the copper particles 14 to the surface of the copper particles 14 close to the first layer of board 12. For example, when the thickness is small, the first hole segment 151 can be drilled by a one-stage drilling method; when the thickness is large, it can also be drilled by a multi-stage drilling method to improve the heat dissipation and chip removal capabilities of the drill bit in the first hole segment 151 drilling project, thereby reducing the wear of the drill bit and the probability of the drill bit breaking.

[0075] Illustratively, the first set distance may be designed according to actual conditions, for example, it may be half the depth of the first hole section 151 .

[0076] S52: The drill bit uses a multi-stage drilling method to form a penetrating second hole segment 152 on the copper particle 14. After each drilling of the copper particle 14 is completed, the drill bit retreats to a second set distance, and the second set distance is less than the drilling depth of the corresponding drilling process on the copper particle 14.

[0077] Specifically, when the second hole section 152 is formed on the copper particle 14 by drilling in multiple stages, the depth of the copper particle 14 drilled by the drill bit each time is small, so that the impact force and wear of the copper particle 14 on the drill bit can be reduced, thereby improving the situation of the drill bit breaking. Since the drill bit retreats to the first set distance after the first hole section 151 is formed in step S51, and the drill bit retreats to the second set distance after each drilling of a section on the copper particle 14, the waste chips formed can be discharged each time the tool is withdrawn, so as to increase the heat dissipation efficiency of the drill bit and reduce the formation of the hole segment. At the same time, it can also ensure that a part of the drill bit is always located in the formed drill hole, which can not only ensure that there will be no problem of mismatching each time the drilling occurs, but also prevent the problem of damaging the drill bit due to one-time hole formation.

[0078] Illustratively, the second set distance may be designed according to actual conditions, for example, it may be half the depth of the corresponding segmented hole set on the copper particle 14 .

[0079] Optionally, in one embodiment, in step S52: the step of using a drill bit to form a penetrating second hole segment 152 on the copper particle 14 by drilling in multiple stages, includes:

[0080] The second hole section 152 is drilled in equal sections or in unequal sections.

[0081] Specifically, during the drilling process on the copper particles 14, the segmented method of the drilling process can be designed according to the thickness of the copper particles 14 to avoid excessive impact force of the copper particles 14 on the drill bit due to excessive drilling depth at one time, thereby reducing drill bit wear and the probability of needle breakage.

[0082] Optionally, in one embodiment, the method further includes: dividing the drilling process of the second hole section 152 into three stages.

[0083] Specifically, the drilling process on the copper grain 14 is divided into three stages according to the thickness of the copper grain 14, so as to ensure that when drilling on the copper grain 14, the impact force of the copper grain 14 on the drill bit can be reduced, so as to reduce the wear of the drill bit and the probability of the drill bit breaking. For example, the drilling process on the copper grain 14 is divided into three equal stages.

[0084] In other embodiments, the drilling process in the copper particle 14 is not limited to three stages, but can also be two stages, three stages, four stages, five stages or more, as long as the drilling process on the copper particle 14 can be effectively divided into multiple stages according to the thickness of the copper particle 14 to reduce the impact force on the drill bit in a continuous drilling process.

[0085] In one embodiment, in step S51, the first hole section 151 is opened on the first layer board 12 by a drill, the first hole section 151 penetrates to the surface of the copper particles 14 close to the first layer board 12, and the drill is retracted to a first set distance, the first set distance is less than the depth of the first hole section 151, including the following steps:

[0086] S511: The drill bit forms the first hole segment 151 in a multi-step drilling manner. After each drilling on the first layer of board 12 is completed, the drill bit retreats a predetermined distance, which is less than the drilling depth of the corresponding drilling process on the first layer of board 12.

[0087] Specifically, when the thickness of the first layer 12 from the surface away from the copper particles 14 to the surface of the copper particles 14 close to the first layer 12 is large, the first hole section 151 is formed by drilling in multiple steps, which is beneficial to increase the chip removal capacity and heat dissipation performance of the drill, thereby ensuring the drilling pass rate and improving the drilling quality. At the same time, it also reduces the force on the drill and the wear of the drill, avoiding the problem of drill needle breakage.

[0088] In schematic form, the predetermined distance is half the depth of the previous hole formed by the drill. Further, when the last step of the drilling process of the first layer 12 is completed and the drill is retracted by the predetermined distance, the distance between the position of the drill and the surface of the copper particle 14 close to the first layer 12 is the first set distance.

[0089] In one embodiment, in step S5: according to the thickness of the multilayer board, a through hole 15 is opened on the multilayer board by a segmented drilling method, and the through hole 15 penetrates the first layer board 12 and the copper particles 14, the following steps are also included:

[0090] S501 : a communication metal layer (not shown) is made in the hole wall of the through hole 15 , so that the communication metal layer is connected to the copper grains 14 .

[0091] Exemplarily, the communication metal layer may be a copper layer. Specifically, after the through hole 15 is formed on the multilayer board, a copper layer may be deposited in the through hole 15 to form a copper communication metal layer in the hole wall of the through hole 15. The communication metal layer enables each circuit layer 102 in the first laminate 11 to maintain communication connection with each circuit layer 102 of the first layer board 12.

[0092] Generally, before laminating multiple circuit boards to form a multilayer board, it is necessary to first machine slots for alignment on the circuit boards so as to accurately press and position the circuit boards using the slots. In some related technologies, the slots for alignment are formed by punching. However, when the thickness of the circuit board is too large, it is difficult for the punching machine to accurately machine the alignment slots.

[0093] Based on this, in one embodiment, refer to Figure 5 and Figure 6 Before step S2: the step of opening a through installation groove on the first pressing plate 11, the following steps are also included:

[0094] S201: Obtaining a controlled depth according to the thickness of the first pressing plate 11;

[0095] Specifically, the controlled depth can be obtained according to the thickness of the first pressed plate 11 and the punching capacity of the punching machine. For example, the controlled depth is equal to the thickness of the first pressed plate 11 minus the punchable thickness of the punching machine. Further, the controlled depth can be set with a certain error based on the above calculation method, such as the controlled depth is equal to the thickness of the first pressed plate 11 minus the punchable thickness of the punching machine ±0.1 mm.

[0096] S202: opening a depth-controlled groove 103 on the first surface of the first pressing plate 11 according to the depth-controlled depth;

[0097] Illustratively, in one embodiment, the depth control groove 103 can be formed by controlling the depth of the first pressing plate 11 to ensure that after the depth control groove 103 is formed, the thickness of the first pressing plate corresponding to the depth control groove 103 can fall within the punching capacity range of the punching machine, thereby ensuring that the punching machine can effectively punch out the first positioning hole 104. In other embodiments, the depth control groove 103 can also be formed in other ways. Furthermore, the center position of the depth control groove 103 is consistent with the center position of the first positioning hole 104 to be formed, and its size should be slightly larger or consistent with the size of the first positioning hole 104 to be formed, so as to ensure that the depth control groove 103 can effectively reduce the thickness of the first pressing plate 11 at the position of the first positioning hole 104, so as to ensure that the punching machine can effectively form the first positioning hole 104.

[0098] S203 : using a punching machine to open a first positioning hole 104 at the bottom of the depth-controlling groove 103 , wherein the first positioning hole 104 penetrates the first pressing plate 11 .

[0099] Specifically, since the depth control groove 103 can reduce the plate thickness at the first positioning hole 104, the plate thickness corresponding to the depth control groove falls within the punching capacity of the punching machine, so that the punching machine can reliably punch out the first positioning hole 104 for alignment on the first pressed plate 11. Furthermore, before the punching machine punches, the punching machine also needs to perform target positioning to ensure that the position of the first positioning hole 104 punched by the punching machine is consistent with the required position.

[0100] Furthermore, in one embodiment, before step S4: laminating the first layer board 12 to the first laminating board 11, wherein the first layer board 12 covers the mounting groove to form a multilayer board, the following steps are also included:

[0101] S401: using a punching machine to open a second positioning hole on the first layer board 12;

[0102] Schematically, when the thickness of the first layer of board 12 is within the punching capacity range of the punching machine, the second positioning hole can be directly formed by the punching machine; when the thickness of the first layer of board 12 exceeds the punching capacity range of the punching machine, refer to the above steps S201 to S203 to perform a depth-controlled groove on the first layer of board 12 before the punching machine forms the second positioning hole to reduce the thickness of the first layer of board 12. The specific process will not be repeated here.

[0103] S402: placing the first pressing plate 11 on the fusion machine through the first positioning hole 104;

[0104] Specifically, the first pressing plate 11 is placed on the fusion machine, and a positioning member (such as a positioning pin) on the fusion machine passes through the first positioning hole 104 to position the first pressing plate 11 .

[0105] S403: Arranging a first prepreg 13 on the second surface of the first pressing plate 11, with the first surface and the second surface being arranged opposite to each other;

[0106] Specifically, the semi-cured sheet is also called "PP sheet". The semi-cured sheet mainly consists of resin and reinforcing materials. The reinforcing materials are divided into , paper-based, composite materials and other types, prepreg can effectively bond multi-layer boards.

[0107] S404: placing the first layer board 12 on the fusion machine through the second positioning hole, the first layer board 12 covering the side of the first prepreg 13 away from the first pressing plate 11;

[0108] Specifically, the first layer of board 12 is covered on the first semi-cured sheet 13, and the positioning piece on the fusion machine passes through the first positioning hole 104 and then through the second positioning hole, so as to use the second positioning hole to position the first layer of board 12, and at the same time use the first positioning hole 104 and the second positioning hole to align the first pressing plate 11 and the first layer of board 12, so as to ensure the accuracy of the first pressing plate 11 and the first layer of board 12 when they are stacked and fused.

[0109] S405: fusing the first pressed plate 11, the first prepreg 13 and the first layer plate 12 by a fusing machine.

[0110] Specifically, at a preset temperature and a preset pressure, the first prepreg 13 melts to bond the first pressing plate 11 and the first layer 12. The first pressing plate 11, the first prepreg 13 and the first layer 12 are pressed together into an integrated structure, ensuring the alignment of the pattern of the first pressing plate 11 and the pattern of the first layer 12, avoiding interlayer slippage during subsequent pressing, thereby ensuring the stability and reliability of the multilayer circuit board.

[0111] Optionally, in one embodiment, after step S4: laminating the first layer board 12 to the first laminating board 11, so that the first layer board 12 covers the mounting groove to form a multilayer board, the following steps are also included:

[0112] S61: removing the burrs on the periphery of the multilayer board;

[0113] Specifically, the burrs on the periphery of the multilayer board can be removed by milling or grinding, so that the edges of the multilayer board are smooth and flat.

[0114] Optionally, in one embodiment, the following steps are also included:

[0115] S62: grinding the surface of the multilayer board to roughen the surface of the multilayer board;

[0116] Specifically, by grinding the surface of the multilayer board, the surface flash of the multilayer board can be removed, the surface of the multilayer board is roughened, and the contact area is increased, which is convenient for the subsequent attachment of an outer copper foil on the surface of the multilayer board.

[0117] Optionally, in one embodiment, the following steps are also included:

[0118] S63: removing excess copper material from the surface of the multilayer board so that the thickness of the multilayer board reaches a preset thickness.

[0119] Specifically, excess copper material on the surface of the multilayer board can be removed by chemical etching or the like, so that the thickness of the multilayer board reaches a preset thickness.

[0120] Optionally, in one embodiment, after step S4: laminating the first layer board 12 to the first laminating board 11, so that the first layer board 12 covers the mounting groove to form a multilayer board, the following steps are also included:

[0121] S71: electroplating a copper layer on the surface of the multilayer board;

[0122] Specifically, a layer of copper is plated on the multilayer board after copper deposition, which can thicken the copper surface and the circuit surface and improve the stability of the circuit board.

[0123] Optionally, in one embodiment, it further includes:

[0124] S72: Making a printing ink layer on the surface of the multilayer board.

[0125] Specifically, by printing a layer of ink on the multilayer board, it can play the role of insulation, anti-welding, and circuit protection. Further, after the ink layer is formed, the multilayer board can also be subjected to surface treatment, gong board, and electrical testing, etc., which will not be expanded here.

[0126] See also Figure 1 , Figure 5 and Figure 6 Optionally, in one embodiment, the first laminated board 11 includes a second layer board 111 and a third layer board 112. Step S1: the step of making the first laminated board 11 specifically includes the following steps:

[0127] S101: manufacturing the second layer board 111 and the third layer board 112 respectively;

[0128] S102: Arranging a second prepreg 113 between the second layer board 111 and the third layer board 112;

[0129] S103 : Pressing the second layer board 111 , the second prepreg 113 and the third layer board 112 together at a preset temperature and a preset pressure to form a first pressed board 11 .

[0130] Specifically, at a preset temperature and a preset pressure, the second prepreg 113 melts to bond the second layer 111 and the third layer 112. The second layer 111, the second prepreg 113, and the third layer 112 are pressed together to form an integrated structure. Further, after the second layer 111, the second prepreg 113, and the third layer 112 are pressed together to form a first pressed plate 11, the first pressed plate 11 can also be subjected to peripheral burr removal, plate grinding, LDI inner layer laser exposure, inner layer etching, inner layer mid-inspection, and inner layer browning, etc., which will not be expanded here.

[0131] See also Figure 7 Optionally, in one embodiment, the first layer board 12, the second layer board 111 and the third layer board 112 all include a substrate 101 and two circuit layers 102 formed on both sides of the substrate 101. Specifically, the steps of making the first layer board 12, the second layer board 111 and the third layer board 112 all include the following steps:

[0132] S11: dividing the bulk material into substrates 101 of a preset size;

[0133] Specifically, the bulk material may be a large-sized copper-clad laminate, and the substrate 101 may be obtained by cutting the large-sized copper-clad laminate into designed sizes.

[0134] S12: manufacturing circuit layers 102 on both sides of the substrate 101;

[0135] Specifically, the steps of making the circuit layer 102 on the substrate 101 are as follows: a photosensitive film is covered on the substrate 101, and ultraviolet rays are irradiated on the substrate 101 covered with the photosensitive film through the master sheet in a vacuum state to project the pattern on the master sheet onto the photosensitive film. Then, the photosensitive film on the light-blocking part (unexposed part) of the substrate 101 blocked by the master sheet is washed off with alkaline water, and the exposed copper is etched off with a chemical solution, so that the circuit layer 102 can be formed on the substrate 101. Finally, the substrate 101 is scanned by an optical instrument to check whether there are any defects.

[0136] S13: performing roughening treatment on the circuit layer 102.

[0137] Exemplarily, the circuit layer 102 can be roughened by browning it. Specifically, the copper on the circuit layer 102 is oxidized to make the circuit layer 102 rough, which can enhance the bonding strength between the circuit layer 102 and the semi-cured sheet during lamination and avoid delamination or board explosion.

[0138] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above 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.

[0139] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood 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 method for manufacturing a multilayer circuit board, characterized in that: include: respectively manufacturing a first pressed board and a first layer board; A penetrating installation groove is provided on the first pressing plate; Place the copper pellets into the mounting slot; Laminating the first layer board to the first laminating board, wherein the first layer board covers the mounting groove, to form a multilayer board; According to the thickness of the multilayer board, a through hole is opened on the multilayer board by using a segmented drilling method, and the through hole penetrates the first layer board and the copper particles.

2. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: In the step of opening a through hole on the multilayer board by drilling in sections according to the thickness of the multilayer board, wherein the through hole penetrates the first layer board and the copper particles, the following steps are included: Opening a first hole section on the first layer board by a drill, the first hole section penetrates to the surface of the copper particles close to the first layer board, and retracting the drill to a first set distance, the first set distance being less than the depth of the first hole section; The drill bit uses a multi-stage drilling method to form a penetrating second hole segment on the copper particle. After each segment of drilling of the copper particle is completed, the drill bit retreats to a second set distance, and the second set distance is less than the drilling depth of the corresponding drilling process on the copper particle.

3. The method for manufacturing a multilayer circuit board according to claim 2, characterized in that: The step of forming a second hole segment penetrating through the copper grain by using a multi-stage drilling method of the drill bit includes: Drilling the second hole section in equal sections or in unequal sections; and / or, The drilling process of the second hole section is divided into three stages.

4. The method for manufacturing a multilayer circuit board according to claim 2, characterized in that: The step of opening a first hole section on the first layer board by a drill, wherein the first hole section penetrates to the surface of the copper particles close to the first layer board, and retracting the drill to a first set distance, wherein the first set distance is less than the depth of the first hole section, includes the following steps: The drill bit forms the first hole segment by drilling in multiple steps. After each drilling on the first layer of board is completed, the drill bit retreats a predetermined distance, and the predetermined distance is less than the drilling depth of the corresponding drilling process on the first layer of board.

5. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: After the step of drilling a through hole in the multilayer board by segmented drilling according to the thickness of the multilayer board, wherein the through hole penetrates the first layer board and the copper particles, the following steps are also included: A communication metal layer is formed in the hole wall of the through hole, so that the communication metal layer is connected to the copper grain.

6. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: Before the step of providing a through installation groove on the first pressing plate, the following steps are also included: According to the thickness of the first pressed plate, obtaining the controlled depth; Opening a depth-controlled groove on the first surface of the first pressing plate according to the depth-controlled depth; A first positioning hole is opened at the bottom of the depth-controlling groove by a punching machine, and the first positioning hole passes through the first pressing plate.

7. The method for manufacturing a multilayer circuit board according to claim 6, characterized in that: Before the step of laminating the first layer board to the first laminating board, wherein the first layer board covers the mounting groove, to form a multilayer board, the step further includes: Opening a second positioning hole on the first layer of board by the punching machine; placing the first pressing plate on the fusion machine through the first positioning hole; A first prepreg is arranged on the second surface of the first pressing plate, and the first surface is arranged opposite to the second surface; The first layer plate is placed on the fusion machine through the second positioning hole, and the first layer plate covers the side of the first prepreg facing away from the first pressing plate; The first pressed board, the first prepreg and the first layer board are fused by the fusion machine.

8. The method for manufacturing a multilayer circuit board according to claim 1, characterized in that: After the step of laminating the first layer board to the first laminating board, wherein the first layer board covers the mounting groove, to form a multilayer board, the following steps are also included: removing burrs from the periphery of the multilayer board; and / or, Grinding the surface of the multilayer board to roughen the surface of the multilayer board; and / or, Excess copper material on the surface of the multilayer board is removed so that the thickness of the multilayer board reaches a preset thickness.

9. The method for manufacturing a multilayer circuit board according to any one of claims 1 to 8, characterized in that: The step of making the first pressed plate specifically includes the following steps: Make the second layer board and the third layer board respectively; Disposing a second prepreg between the second layer and the third layer; The second layer board, the second prepreg sheet and the third layer board are pressed together at a preset temperature and a preset pressure to form the first pressed board.

10. The method for manufacturing a multilayer circuit board according to claim 9, characterized in that: The steps of making the first layer board, making the second layer board and making the third layer board all include the following steps: Divide bulk materials into substrates of preset sizes; Manufacturing circuit layers on both sides of the substrate; The circuit layer is roughened.

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