Copper-embedded block plate manufacturing method and copper-embedded block plate

Abstract

The application discloses a buried copper block plate manufacturing method and a buried copper block plate, relates to the field of PCB manufacturing technology, and comprises the following steps: obtaining a first multilayer subplate, a second multilayer subplate and a plurality of resin plates; windows matched with the buried copper block are formed in the first multilayer subplate, the second multilayer subplate and the plurality of resin plates; one end of the buried copper block is embedded in the first multilayer subplate, the other end of the buried copper block sequentially passes through the plurality of resin plates and is embedded in the second multilayer subplate, and a first laminated plate is obtained; the first laminated plate is pressed, and a buffer film is attached to the side surfaces of the first multilayer subplate and the second multilayer subplate away from the resin plates during the pressing; the buffer film comprises a first PET resin, a second PET resin and a first resin, the first resin is arranged between the first PET resin and the second PET resin, and the first resin is PE resin or PO resin; and the first laminated plate after the pressing is processed to obtain the buried copper block plate. Through the method, the yield of the PCB plate can be improved.

Description

Technical Field

[0001] This application relates to the field of PCB manufacturing technology, and in particular to a method for manufacturing a copper-embedded board and the copper-embedded board itself. Background Technology

[0002] With the development of electronic technology and people's demands for miniaturization and high integration of electronic products, the capacitance of MEMS products on printed circuit boards has a significant impact on the performance of printed circuit boards. Since the dielectric layer of high-capacitance-density materials is extremely thin, the voltage withstand capability of capacitors has become one of the important issues in the use and manufacturing process of printed circuit boards. Therefore, in related technologies, copper blocks are usually embedded in multilayer circuit boards to solve the above problem. However, the method of embedding copper blocks in high-speed communication boards in related technologies tends to lead to low yield rates. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a method for manufacturing a copper-embedded board and a copper-embedded board, which can improve the yield of PCB boards.

[0004] In a first aspect, embodiments of this application provide a method for manufacturing a copper-embedded block board, including:

[0005] Obtain a first multilayer sub-board, a second multilayer sub-board, and several resin boards;

[0006] Windows adapted to the embedded copper blocks are provided in the first multilayer sub-board, the second multilayer sub-board, and several resin boards.

[0007] One end of the embedded copper block is embedded in the first multilayer sub-board, and the other end of the embedded copper block passes through several resin boards in sequence and is embedded in the second multilayer sub-board to obtain a first laminated board, wherein the thickness of the embedded copper block is greater than the thickness of the first laminated board.

[0008] The first laminated board is pressed together, and during pressing, a buffer film is respectively attached to the side surface of the first multilayer sub-board and the second multilayer sub-board away from the resin board. The buffer film includes a first PET resin, a second PET resin and a first resin. The first resin is disposed between the first PET resin and the second PET resin. The first resin is PE resin or PO resin.

[0009] The first laminated plate, after being pressed, is processed to obtain a copper-embedded plate.

[0010] According to one or more technical solutions provided in the embodiments of this application, at least the following beneficial effects are achieved: By providing buffer films on the upper and lower surfaces of the first laminated plate during pressing, the buffer films include a first PET resin, a second PET resin, and a first resin, with the first resin positioned between the first and second PET resins. The first resin is either PE resin or PO resin. A three-in-one buffer film is used for pressure equalization: the flow temperature of the PE resin or PO resin layer is near the lowest viscosity value of most resin boards. The flowing pressure-transmitting medium layer ensures that the pressed product achieves true hydrostatic pressure, which has a positive effect on resin filling, especially low-flow resin filling. This buffer film has functions of filling high and low differences, equalizing pressure, releasing, and preventing glue adhesion. Furthermore, the buffer film contains very little silicone, so it will not remain on the steel plate or the board surface, effectively controlling expansion and contraction, making the board dimensions more stable. This application improves the pressing effect and increases product yield through this design.

[0011] According to some embodiments of the first aspect of this application, the window size is larger than the copper embedding block size, the plurality of windows form a copper embedding slot, and after the copper embedding block is disposed in the copper embedding slot, the distance between the window on the resin board that is adapted to the copper embedding block and the copper embedding block is between 0.075mm and 0.2mm, and the opening on the resin board is adapted to the opening of the first multilayer sub-board and the second multilayer sub-board.

[0012] According to some embodiments of the first aspect of this application, the processing of the first laminated plate after pressing includes:

[0013] The first laminated board, after being pressed, is subjected to the following processes in sequence: first edge milling and drilling of target holes, drilling of mechanical blind holes, first copper plating, first hole plating, resin plugging, outer dry film, second drilling of target holes, and CNC milling, to obtain the second laminated board.

[0014] According to some embodiments of the first aspect of this application, the operation steps of the CNC milling include:

[0015] The expansion and contraction and slot positioning of the second target hole obtained through the second drilled target hole are measured by the inner layer PAD so that the size of the second target hole after copper plating meets the preset requirements.

[0016] Based on the expansion and contraction and the results of the groove positioning measurement, the second laminated board is subjected to secondary pairing, pressing and embedding of copper blocks, second milling and drilling of target holes, drilling, second copper plating, second hole plating, selection of resin plugging, third copper plating, outer dry film, solder resist, forming and testing to obtain the copper-embedded board.

[0017] According to some embodiments of the first aspect of this application, the drilling operation steps include:

[0018] The drill bit is compensated for all the first electroplated through holes obtained through the drilling to obtain a number of second electroplated through holes.

[0019] According to some embodiments of the first aspect of this application, the second copper plating operation includes:

[0020] Each of the second electroplated through holes is sequentially treated with desizing, chemical copper plating, and copper plating to obtain a second laminated board in which the interlayer pattern lines are interconnected.

[0021] According to some embodiments of the first aspect of this application, the operation steps of the outer dry film include:

[0022] The second laminate is subjected to drying film, exposure, development, etching and film removal processes in sequence, and independent PADs are etched on the second laminate to obtain a second laminate with outer layer circuitry.

[0023] According to some embodiments of the first aspect of this application, before opening windows adapted to the embedded copper blocks in the first multilayer sub-board, the second multilayer sub-board, and the plurality of resin boards, the following steps are included:

[0024] The substrate is cut to a preset size, and inner layer circuitry is fabricated on the substrate to obtain an inner layer core board;

[0025] According to the preset design route, the inner layer circuit is subjected to AOI inspection;

[0026] The inner core board is subjected to browning treatment to obtain the first multilayer sub-board and the second multilayer sub-board.

[0027] According to some embodiments of the first aspect of this application, the step of fabricating inner layer circuitry on the substrate to obtain an inner layer core board includes:

[0028] The substrate is sequentially coated with a wet film, exposed, developed, etched, and stripped to obtain the first multilayer sub-board and the second multilayer sub-board with inner layer circuitry.

[0029] Secondly, embodiments of the present invention also provide a copper-embedded block plate, comprising:

[0030] First multilayer sub-board;

[0031] The second multilayer sub-board is disposed opposite to the first multilayer sub-board;

[0032] A plurality of resin boards are disposed between the first multilayer sub-board and the second multilayer sub-board, and the first multilayer sub-board, the second multilayer sub-board and the plurality of resin boards are all provided with windows adapted to the embedded copper block.

[0033] At least two buffer films are provided, with the buffer films respectively attached to the surfaces of the first multilayer sub-board and the second multilayer sub-board away from the resin board, so as to sequentially press and process the first laminated board with the buffer films to obtain the embedded copper block board.

[0034] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0035] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of the application.

[0036] Figure 1 This is a schematic flowchart of a method for manufacturing a copper-embedded block plate according to an embodiment of this application;

[0037] Figure 2 This is a schematic diagram of the structure of the embedded copper block plate provided in the embodiments of this application;

[0038] Figure 3 This is a schematic diagram of the structure of the buffer membrane provided in the embodiments of this application;

[0039] Figure 4 This is a schematic diagram of a structure with a window on a resin plate according to an embodiment of this application;

[0040] Figure 5 This is a schematic diagram of the process for fabricating a copper-embedded block board after lamination, provided in another embodiment of this application;

[0041] Figure 6 This is a schematic diagram illustrating the specific process of fabricating a copper-embedded plate after lamination, provided in another embodiment of this application.

[0042] Figure 7 This is a schematic diagram of the process for obtaining a copper-embedded board according to another embodiment of this application;

[0043] Figure 8 This is a schematic diagram of the structure for positioning and measuring the groove inside the gong according to another embodiment of this application;

[0044] Figure 9 This is a schematic diagram illustrating the specific process of obtaining the embedded copper block board according to another embodiment of this application;

[0045] Figure 10 This is a schematic diagram of a drill bit compensation process provided in another embodiment of this application;

[0046] Figure 11 This is a schematic diagram of a drill bit compensation process provided in another embodiment of this application;

[0047] Figure 12 This is a schematic diagram of the process for obtaining the second composite plate provided in another embodiment of this application;

[0048] Figure 13 This is a schematic diagram of the process for obtaining a second laminated board with outer layer circuitry provided in another embodiment of this application;

[0049] Figure 14 This is a schematic diagram of the process for obtaining an inner layer core board with inner layer circuitry provided in another embodiment of this application;

[0050] Figure 15 This is a schematic diagram of the process for fabricating a copper block board before lamination, provided in another embodiment of this application. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0052] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0053] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection or a connection that allows communication between the two components; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components, an indirect connection, or an interaction between two components.

[0055] In the description of this invention, unless otherwise explicitly defined, terms such as setting, installing, and connecting should be interpreted broadly. Those skilled in the art can understand the specific meaning of the above terms in the invention according to the specific circumstances.

[0056] With the development of electronic technology and people's demands for miniaturization and high integration of electronic products, the capacitance of MEMS products on printed circuit boards has a significant impact on the performance of printed circuit boards. Since the dielectric layer of high-capacitance-density materials is extremely thin, the voltage withstand capability of capacitors has become one of the important issues in the use and manufacturing process of printed circuit boards. Therefore, in related technologies, copper blocks are usually embedded in multilayer circuit boards to solve the above problem. However, the method of embedding copper blocks in high-speed communication boards in related technologies tends to lead to low yield rates.

[0057] Due to the rapid development of the PCB industry, the design requirements for high-speed communication boards with embedded copper blocks are constantly increasing. This also raises the requirements for the manufacturing process capabilities of these boards. The main difficulty in manufacturing conventional PCB high-speed communication boards with embedded copper blocks is related to the lamination design, especially for PCB designs with two or more laminations when embedding the copper blocks. In related technologies, the conventional single-layer PET release film is used in the manufacturing of high-speed communication boards with embedded copper blocks. The thickness of the embedded copper block is determined based on the actual board thickness measured before the second lamination of the layers. However, the buffering capacity of the PET release film is poor, which easily leads to problems such as excess adhesive and abnormal quality. Furthermore, if the thickness of the embedded copper block is determined based on the actual board thickness measured before the second lamination of the layers, it is easy to cause problems such as excess adhesive and pits in the embedded copper area, resulting in lower production quality.

[0058] Based on the above, this application provides a method for manufacturing a copper embedded plate and a copper embedded plate, which reduces production difficulty and improves production quality.

[0059] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0060] The first aspect of this application specifically provides a method for manufacturing a copper embedded block board, such as... Figure 1 and Figure 3 As shown, the method for manufacturing copper-embedded blocks includes, but is not limited to, the following steps:

[0061] Step S100: Obtain the first multilayer sub-board, the second multilayer sub-board, and several resin boards;

[0062] Step S200: Open windows adapted to the embedded copper blocks on the first multilayer sub-board, the second multilayer sub-board, and several resin boards.

[0063] Step S300: One end of the embedded copper block is embedded in the first multilayer sub-board, and the other end of the embedded copper block passes through several resin boards in sequence and is embedded in the second multilayer sub-board to obtain the first composite board, wherein the thickness of the embedded copper block is greater than the thickness of the first composite board.

[0064] Step S400: Press the first laminated board together, and during pressing, a buffer film is respectively attached to the side surface of the first multilayer sub-board and the second multilayer sub-board away from the resin board; the buffer film includes a first PET resin, a second PET resin and a first resin, the first resin is disposed between the first PET resin and the second PET resin, and the first resin is PE resin or PO resin.

[0065] Step S500: The first laminated plate after pressing is processed to obtain the copper embedded plate.

[0066] It should be noted that copper embedding slots are formed at the openings corresponding to the copper embedding blocks on the first multilayer sub-board, the second multilayer sub-board, and several resin boards, and the copper embedding blocks are placed into the copper embedding slots.

[0067] In this application, multiple PCB boards and resin boards are respectively provided with windows adapted to the embedded copper blocks. Multiple PCB boards and resin boards are sequentially stacked to form a first laminated board. Embedded copper slots are formed at the corresponding windows on the PCB boards and resin boards, allowing the embedded copper blocks to be placed within these slots. This reduces the distance between the resin board window and the embedded copper block housed within it, effectively curing the embedded copper block and reducing the risk of adhesive overflow and slot misalignment. The thickness of the embedded copper block is greater than the thickness of the first laminated board because the resin board in the first laminated board thins under pressure. Therefore, after lamination into the embedded copper block board, the thickness of the embedded copper block will inevitably be greater than the thickness of the embedded copper block board, causing both surfaces of the embedded copper block to protrude from the board surface, which is beneficial for subsequent grinding and cleaning of adhesive overflow on the embedded copper block. During lamination, the first... The upper and lower surfaces of the laminated board are respectively provided with buffer films. The buffer films include a first PET resin, a second PET resin, and a first resin, with the first resin positioned between the first and second PET resins. The first resin is either PE resin or PO resin. A three-in-one buffer film is used for pressure equalization: the flow temperature of the PE resin or PO resin layer is near the lowest viscosity value of most resin boards. The flowing pressure-transmitting medium layer ensures that the laminated product achieves true hydrostatic pressure, which has a positive effect on resin filling, especially low-flow resin filling. This buffer film has the functions of filling high and low differences, equalizing pressure, releasing, and preventing glue from sticking. Moreover, the buffer film contains very little silicone and will not remain on the steel plate or the board surface, effectively controlling expansion and contraction, making the board dimensions more stable. This application improves the lamination effect and increases the product yield through this setting.

[0068] It should be noted that PET stands for Polyethylene terephthalate, and PET resin is an abbreviation for polyethylene terephthalate resin; PO represents PLOY polymer, and PO resin is a homopolymer of high molecular weight ethylene, which is polymerized with olefins such as ethylene, propylene, and butene, and also includes some specialty blends, reinforcements, and complexes; PE stands for polyethylene, and PE resin refers to polyethylene, which is a thermoplastic resin obtained by polymerizing ethylene.

[0069] In this embodiment, the resin board is a PP sheet, which is made of polypropylene, a thermoplastic resin produced by polymerizing propylene.

[0070] In some embodiments, refer to Figure 2 The method for fabricating embedded copper blocks is applied to the fabrication of high-multilayer high-speed communication boards with embedded T-shaped copper blocks. That is, the embedded copper blocks are set in a T-shape and there are eight layers of PCB boards. The first to eighth layers of PCB boards are represented by sub-boards L1, L2, L3, L4, L5, L6, L7 and L8, respectively. The first multilayer sub-board refers to sub-boards L1 to L4, and the second multilayer sub-board refers to sub-boards L5 to L8. Windows corresponding to the T-shaped embedded copper blocks are opened at the positions of the L1 to L8 sub-boards. Multiple windows form embedded copper slots, and the T-shaped embedded copper blocks are embedded in the embedded copper slots. When laminating sub-boards L1 to L8, the opening of the resin board is reduced to bring the embedded copper block closer to the resin board. This setting effectively solidifies the embedded copper holes and avoids risks such as overflowing adhesive and misalignment of the copper block holes. A three-in-one buffer film is used to buffer and equalize the pressure. By using the combination of PCB board and buffer film as the covering material during lamination, the problem of adhesive overflow after sanding cannot be removed is improved, further improving production efficiency and product quality. The PCB board represents sub-boards L1 to L8.

[0071] Specifically, the first composite board is composed of: layers L1 to L2 + layers L3 to L4 + resin board, and layers L5 to L6 + layers L7 to L8 + resin board, that is, two layers of resin board are provided between the sub-boards of layers L1 to L4 and the sub-boards of layers L5 to L8.

[0072] In related technologies, the L1 to L8 layer sub-board lamination production method uses the traditional PROG7 press program. However, the PROG7 press program is prone to causing copper block dents and glue overflow, leading to quality abnormalities. The traditional PROG7 press program design is shown in the table below:

[0073]

[0074]

[0075] Based on this, this application changes the pressing stroke during the lamination of sub-boards from L1 to L8, changing the prog7 press program to the prog8 press program to reduce the probability of copper block indentation and adhesive overflow. The specific pressing parameters for the buffer-related pressure adjustment of the prog8 press program are shown in the table below:

[0076]

[0077] Reference Figure 4 It is understood that the window size is larger than the copper block size, and multiple windows form a copper embedding slot. After the copper block is placed in the copper embedding slot, the distance between the window on the resin board that is compatible with the copper block and the copper block is between 0.075mm and 0.2mm. The openings on the resin board are compatible with the openings of the first multilayer sub-board and the second multilayer sub-board.

[0078] In related technologies, the PP window is designed to be 0.20mm away from the copper block, which easily leads to gaps in the embedded copper block, resulting in issues such as dents, excess adhesive, and misalignment of the embedded copper block holes. Therefore, this application reduces the size of the window on the resin board, placing the distance between the window on the resin board that matches the embedded copper block and the embedded copper block between 0.075mm and 0.2mm. This brings the embedded copper block closer to the resin board, effectively solidifying the embedded copper holes and avoiding risks such as excess adhesive and misalignment of the copper block holes.

[0079] In this embodiment, refer to Figure 4 The distance between the window on the resin board that matches the copper embedding block and the copper embedding block is 1mm, which effectively solidifies the copper embedding block hole, i.e., the copper embedding slot hole, reducing the occurrence of voids caused by insufficient glue flow at the gap between the copper embedding block and the PCB board, while also reducing the risks of glue overflow and copper embedding block hole misalignment.

[0080] It should be noted that the size and shape of the windows corresponding to the embedded copper blocks in the first multilayer sub-board, the second multilayer sub-board, and several resin boards are all adapted to the size and shape of the embedded copper blocks.

[0081] Reference Figures 5 to 6 It is understood that the processing of the first laminated plate after pressing in step S500 includes, but is not limited to, the following steps:

[0082] Step S510: The first laminated board after pressing is subjected to the following steps in sequence: first edge milling and drilling of target holes, drilling of mechanical blind holes, first copper plating, first hole plating, resin plugging, outer dry film, second drilling of target holes and CNC milling, to obtain the second laminated board.

[0083] Specifically, multiple first electroplated through holes are obtained by first milling and drilling target holes and drilling mechanical blind holes. Each first electroplated through hole is then subjected to desmearing, chemical copper plating and electroplating copper plating in sequence through the first copper plating process to obtain a first laminated board with interconnected interlayer pattern lines. The first electroplated through holes on the first laminated board are then filled with resin.

[0084] Reference Figures 7 to 9 It is understandable that the operation steps of CNC milling include, but are not limited to, the following:

[0085] Step S520: The expansion and contraction and slot positioning of the second target hole obtained through the second drilled target hole are measured by the inner layer PAD so that the size of the second target hole after copper plating meets the preset requirements.

[0086] Step S530: Based on the results of expansion and contraction and slot positioning measurements, the second laminated board is subjected to secondary pairing, pressing and embedding of copper blocks, second milling and drilling of target holes, drilling, second copper plating, second hole plating, selection of resin plugging, third copper plating, outer dry film, solder resist, forming and testing to obtain the embedded copper block board.

[0087] In the related copper-embedded board manufacturing process, alignment is achieved through PAD holes. However, the expansion and contraction are significantly affected by multiple processes, resin-filled holes, baking, and ceramic grinding during the layer board production process, which can easily lead to misalignment. Therefore, misalignment issues are prone to occur in the inner grooves of layers L1 to L4 and layers L5 to L8. Based on the above, referring to... Figure 8 In this application, the inner layer expansion and contraction PAD is used to measure expansion and contraction and to position the slots in the L1 to L4 and L5 to L8 sub-boards, which can effectively improve the misalignment problem.

[0088] Specifically, expansion and contraction are usually not measured inside the inner layer of the slot. When making the slot, expansion and contraction are measured and the slot is positioned by the second target hole. That is, a second target hole is drilled in the slot through the second drill target hole, and expansion and contraction are measured again using the second target hole. The first target hole obtained through the first drill target hole may change and expand and contract during the production process. By measuring the expansion and contraction of the second drill target hole and positioning the slot, the positioning accuracy is improved after measuring the expansion and contraction, which can effectively improve the deviation problem.

[0089] For sub-boards L1 to L4 and L5 to L8, a "second drill target hole" is added. First, OPE punches the riveting hole, and then the expansion and contraction are measured with the newly punched riveting hole before the board is rotated for CNC milling. Normal OPE punching of the riveting hole is used to prevent large gaps in the inner groove of the router from causing the OPE to not be able to adhere and punch the hole. When the PNL is used for router copper block placement, the gaps in the router are placed inward to reduce the misalignment of the inner groove due to board expansion and contraction.

[0090] It should be noted that the second laminated board after solder resist treatment is subjected to character processing, CNC machining, electrical testing, and surface treatment in sequence to form the second laminated board and perform testing.

[0091] Specifically, the secondary pairing and lamination of embedded copper blocks refers to the combination of L1 to L4 sub-boards + L5 to L8 sub-boards + embedded copper blocks and resin board; after a second milling and drilling of target holes and holes, multiple second electroplated through holes are obtained. Each second electroplated through hole is subjected to desmearing, chemical copper and electroplating copper treatment in sequence through a second copper plating process to obtain a second laminated board with interconnected interlayer pattern lines. Then, the first electroplated through holes on the second laminated board are filled with resin; solder resist refers to the formation of a solder resist ink layer on the surface of the embedded copper block through solder resist pretreatment, printing, pre-baking, exposure, development and post-baking to obtain the embedded copper block board, in which the independent PADs corresponding to the through holes are located on the first copper foil layer and covered under the solder resist ink layer; forming and testing refers to: milling, electrical testing and inspection, and packaging into finished products for shipment, thus obtaining the embedded copper block board.

[0092] Reference Figure 10 It is understandable that the drilling operation steps include, but are not limited to, the following:

[0093] Step S531: Drill bit compensation is performed on all the first electroplated through holes obtained by drilling to obtain a plurality of second electroplated through holes.

[0094] In related technologies, during the plating of PTH through-holes on sub-boards of layers L1 to L8, the hole diameter compensation is as follows: the hole tolerance is a partial tolerance, and the drill bit compensation is +0.10mm. However, since the copper thickness of all conventional PTH through-holes is relatively thick, this hole diameter compensation method has the risk of small holes and abnormal phenomena such as hole diameter exceeding tolerance. Therefore, this application performs drill bit compensation on all first electroplated through-holes, changing the original through-hole PTH hole drill bit compensation from +0.10 to +0.15mm, reducing the risk of small holes and abnormal phenomena such as hole diameter exceeding tolerance, and improving the related quality defects of the embedded copper block. The specific hole diameter compensation for PTH through-holes during plating of sub-boards of layers L1 to L8 in the related technologies is shown in the table below:

[0095] Required aperture tolerance Outer DF back aperture After copper reduction, the aperture 0.60mm +0.10 / _0.05 0.525 0.575 0.70mm +0.10 / _0.05 0.525 0.575 1.00mm +0.10 / _0.05 0.525 0.975 2.70mm +0.10 / _0.05 0.525 2.675

[0096] This application applies drill bit compensation to all first electroplated through holes, as detailed in the table below:

[0097] Required aperture tolerance +0.15mm outer DF back aperture 0.60mm +0.10 / _0.05 0.525 0.70mm +0.10 / _0.05 0.675 1.00mm +0.10 / _0.05 0.975 2.70mm +0.10 / _0.05 2.675

[0098] It should be noted that PTH stands for Plating Through Hole, which means through-hole component, indicating electroplated through-hole.

[0099] Reference Figure 13It is understandable that the second copper plating process includes, but is not limited to, the following steps:

[0100] In step S532, each second electroplated through hole is sequentially treated with desmearing, chemical copper plating, and copper plating to obtain a second laminated board in which the interlayer pattern lines are interconnected.

[0101] Specifically, the process includes: removing adhesive residue: using plasma to remove adhesive residue generated during drilling; chemical copper: depositing a thin, uniform, and conductive chemical copper layer in the second electroplating through-hole through a chemical reaction; and electroplating copper: plating an electroplated copper layer onto the surface of the chemical copper layer through an electroplating process.

[0102] Reference Figure 12 It is understandable that the operation steps for the outer dry film include, but are not limited to, the following:

[0103] In step S533, the second laminate is subjected to drying film, exposure, development, etching and film removal processes in sequence, and an independent PAD is formed by etching the second laminate to obtain a second laminate with outer layer circuitry.

[0104] Specifically, the process involves: pressing the photosensitive dry film onto the surface of the second laminated board using hot pressing; exposure: using an LDI exposure machine to polymerize the photosensitive material in the photosensitive dry film, thereby transferring the designed pattern onto the photosensitive dry film; development: removing the unexposed dry film through a saponification reaction between the developer and the dry film; etching: spraying copper chloride solution onto the copper surface using an etching machine, and using the chemical reaction between the solution and copper to etch the copper surface not protected by the dry film, forming the circuit; and stripping: spraying NaOH or KOH solution onto the board surface using a stripping machine, and using the chemical reaction between the solution and the dry film to remove the dry film, completing the fabrication of the outer layer circuitry and obtaining the second laminated board with the outer layer circuitry.

[0105] It should be noted that in PCB design, PAD stands for solder pad, which is the part of the PCB board where the pins of components are soldered together. It consists of copper foil and holes, and the copper foil must be exposed. It cannot be covered by solder mask. The outer layer PAD refers to the part without the coating.

[0106] Reference Figure 13 It is understood that prior to step S200, the following steps are included, but are not limited to:

[0107] Step S210: Cut the substrate to a preset size and fabricate the inner layer circuitry on the substrate to obtain the inner layer core board;

[0108] Step S220: Perform AOI inspection on the inner layer circuit according to the preset design circuit;

[0109] Step S230: The inner core board is browned to obtain the first multilayer sub-board and the second multilayer sub-board.

[0110] It should be noted that, referring to Figure 15 Before step S200, multiple substrates are sequentially subjected to cutting, inner layer circuitry, inner layer AOI inspection and lamination processes to obtain multiple PCB boards.

[0111] Specifically, material cutting: The substrate is cut into a certain size to form 4 Core substrates, which are defined as L12 layer, L34 layer, L45 layer and L78 layer respectively. The 49×41 inch large material size is cut into PCBs to process 24.5×20.5 inch pn l size. Here, pn l means large size. PNL is the production size of a single panel calculated by the PCB (circuit board) manufacturer based on the customer's size. Inner layer circuitry: Layers L1 to L2, L3 to L4, L4 to L5, and L7 to L8 are coated with wet film, exposed, developed, etched, and stripped. According to the PCB stack-up requirements, only the line widths of L2 and L7 surfaces are etched in layers L1 to L2 and L7 to L8, while large copper surfaces are made in L1 and L8 surfaces. Inner layer AOI inspection: According to the preset design circuitry, the actual pattern of the inner layer circuitry of layers L1 to L2, L3 to L4, L4 to L5, and L7 to L8 on the PCB board is inspected, and defective points are identified.

[0112] It should be noted that browning treatment refers to applying an organic film to the surface of the core board layers L1 to L2, L3 to L4, L4 to L5, and L7 to L8 of the PCB board using browning solution, thereby increasing the bonding strength between the PP sheet and the core board.

[0113] Reference Figure 14 It is understood that step S210, which involves fabricating inner layer circuitry on a substrate to obtain an inner layer core board, includes, but is not limited to, the following steps:

[0114] Step S211 involves sequentially coating the substrate with a wet film, exposing it, developing it, etching it, and removing the film to obtain an inner core board with inner layer circuitry.

[0115] Specifically, wet coating refers to uniformly applying green paint or other inks onto the inner core board, pre-baking to locally cure it, and then obtaining the desired pattern and thickness through exposure, development, etching, and film removal. Exposure: The green paint window areas are defined using an LDI exposure machine, and ultraviolet light is used to polymerize and strengthen the structure of the photosensitive parts. Development: The unexposed photosensitive ink is dissolved and removed with a developer to achieve the development purpose. Etching: Copper chloride solution is sprayed onto the copper surface using an etching machine, and the chemical reaction between the solution and copper is used to etch the copper surface that is not protected by the dry film to form the circuit. Film removal: NaOH or KOH solution is sprayed onto the board surface using a film removal machine, and the dry film is removed by the chemical reaction between the solution and the dry film, completing the fabrication of the inner layer circuit and obtaining the inner core board with the inner layer circuit.

[0116] It should be noted that applying the copper-embedded block board manufacturing method of this application to the new manufacturing process of high-multilayer copper-embedded block high-speed communication boards can effectively solve problems such as copper-embedded block inner groove misalignment, OPE punching abnormality, riveting pattern X-RAY recognition abnormality, copper-to-FR4 gap filling abnormality, and incomplete removal of adhesive from the bottom of T-shaped copper blocks in the design of PCB boards with more than two layers of copper-embedded blocks.

[0117] Secondly, referring to Figures 2 to 3 This invention provides a copper-embedded board, which includes a first multilayer sub-board, a second multilayer sub-board, several resin boards, and at least two buffer films. The second multilayer sub-board is disposed opposite to the first multilayer sub-board. Several resin boards are disposed between the first multilayer sub-board and the second multilayer sub-board, and the first multilayer sub-board, the second multilayer sub-board, and several resin boards are all provided with windows adapted to the copper-embedded board. Buffer films are respectively attached to the surfaces of the first multilayer sub-board and the second multilayer sub-board away from the resin boards, so as to sequentially press and process the first laminated board with buffer films to obtain the copper-embedded board.

[0118] It should be noted that the embedded copper plate is obtained by the embedded copper plate manufacturing method described in the first aspect embodiment above.

[0119] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0120] The above description is the preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

[0121] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for manufacturing a copper-embedded block plate, characterized in that, include: Obtain a first multilayer sub-board, a second multilayer sub-board, and several resin boards; Windows adapted to the embedded copper blocks are provided in the first multilayer sub-board, the second multilayer sub-board, and several resin boards. One end of the embedded copper block is embedded in the first multilayer sub-board, and the other end of the embedded copper block passes through several resin boards in sequence and is embedded in the second multilayer sub-board to obtain a first laminated board, wherein the thickness of the embedded copper block is greater than the thickness of the first laminated board. The first laminated board is pressed together, and during pressing, a buffer film is respectively attached to the side surface of the first multilayer sub-board and the second multilayer sub-board away from the resin board. The buffer film includes a first PET resin, a second PET resin and a first resin. The first resin is disposed between the first PET resin and the second PET resin. The first resin is PE resin or PO resin. The first laminated plate after pressing is subjected to the following steps in sequence: first edge milling and drilling of target holes, drilling of mechanical blind holes, first copper plating, first hole plating, resin plugging, outer dry film, second drilling of target holes and CNC milling, to obtain the second laminated plate. The expansion and contraction and the groove positioning of the second target hole obtained through the second drilled target hole are measured by the inner layer PAD so that the size of the second target hole after copper plating meets the preset requirements. Based on the expansion and contraction and the results of the groove positioning measurement, the second laminated board is subjected to secondary pairing, pressing and embedding of copper blocks, secondary milling and drilling of target holes, drilling, secondary copper plating, secondary plating of holes, selection of resin plugging of holes, tertiary copper plating, outer dry film, solder resist, forming and testing to obtain the embedded copper block board; wherein, the drill bit compensation is required for the multiple first electroplated through holes obtained through drilling to obtain multiple second electroplated through holes; the drill bit compensation is +0.15mm.

2. The method for manufacturing an embedded copper block plate according to claim 1, characterized in that, The window size is larger than the copper embedding block size, and multiple windows form copper embedding slots. After the copper embedding block is placed in the copper embedding slots, the distance between the window on the resin board that is adapted to the copper embedding block and the copper embedding block is between 0.075mm and 0.2mm. The window on the resin board is adapted to the window of the first multilayer sub-board and the second multilayer sub-board.

3. The method for manufacturing an embedded copper block plate according to claim 2, characterized in that, The second copper plating operation includes: Each of the second electroplated through holes is sequentially treated with desizing, chemical copper plating, and copper plating to obtain a second laminated board in which the interlayer pattern lines are interconnected.

4. The method for manufacturing an embedded copper block plate according to claim 1, characterized in that, The operation steps of the outer dry film include: The second laminate is subjected to drying film, exposure, development, etching and film removal processes in sequence, and independent PADs are etched on the second laminate to obtain a second laminate with outer layer circuitry.

5. The method for manufacturing an embedded copper block plate according to claim 1, characterized in that, Before opening windows adapted to the embedded copper blocks in the first multilayer sub-board, the second multilayer sub-board, and the plurality of resin boards, the process includes: The substrate is cut to a preset size, and inner layer circuitry is fabricated on the substrate to obtain an inner layer core board; According to the preset design route, the inner layer circuit is subjected to AOI inspection; The inner core board is subjected to browning treatment to obtain the first multilayer sub-board and the second multilayer sub-board.

6. The method for manufacturing an embedded copper block plate according to claim 5, characterized in that, The process of fabricating inner layer circuitry on the substrate to obtain an inner layer core board includes: The substrate is sequentially coated with a wet film, exposed, developed, etched, and stripped to obtain the first multilayer sub-board and the second multilayer sub-board with inner layer circuitry.

7. A copper-embedded plate, characterized in that, The copper-embedded plate is manufactured by the copper-embedded plate manufacturing method as described in any one of claims 1 to 6; The copper-embedded plate includes: First multilayer sub-board; The second multilayer sub-board is disposed opposite to the first multilayer sub-board; A plurality of resin boards are disposed between the first multilayer sub-board and the second multilayer sub-board, and the first multilayer sub-board, the second multilayer sub-board and the plurality of resin boards are all provided with windows adapted to the embedded copper block. At least two buffer films are provided, with the buffer films respectively attached to the surfaces of the first multilayer sub-board and the second multilayer sub-board away from the resin board, so as to sequentially press and process the first laminated board with the buffer films to obtain the embedded copper block board.

Images