Manufacturing method of printed circuit board and printed circuit board

Abstract

The invention discloses a manufacturing method of a printed circuit board and the printed circuit board, and relates to the field of printed circuit board manufacturing, and the method comprises the steps: carrying out the electroplating thickening of a designated line network region of a printed circuit board substrate, and obtaining a first preformed printed circuit board, the printed circuit board substrate is a printed circuit board substrate manufactured according to a preset process, and the specified line network area is an area in which a pre-marked current-carrying line network of which the internal resistance needs to be controlled is located; and carrying out layer adding treatment on the first preformed printed circuit board to obtain a manufactured printed circuit board. The production cost is reduced and the production efficiency is improved on the premise of ensuring the current-carrying capability and the heat dissipation performance of the printed circuit board.

Description

Technical Field

[0001] The present invention relates to the field of printed circuit board manufacturing, and in particular to a method for manufacturing a printed circuit board and the printed circuit board. Background Art

[0002] In the field of printed circuit board (PCB) manufacturing, increasing the number of PCB layers is often employed to improve a PCB's current-carrying capacity and heat dissipation performance. This involves completely separating signal lines from power lines, placing them on different layers. This physical isolation reduces signal interference and optimizes heat dissipation paths. However, this approach doubles material consumption and reduces processing efficiency. For example, each additional layer requires additional prepreg, copper foil, and auxiliary materials, increasing raw material consumption. Furthermore, repeated processes such as lamination, laser drilling, and electroplating fill holes are required, reducing production efficiency.

[0003] Therefore, how to ensure the current carrying capacity and heat dissipation performance of the printed circuit board while reducing costs and improving production efficiency is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] The present invention provides a method for manufacturing a printed circuit board and a printed circuit board, so as to solve the technical problem that in the prior art printed circuit boards, increasing the number of layers to improve the current carrying capacity and heat dissipation performance leads to increased costs and low manufacturing efficiency.

[0005] In a first aspect, a method for manufacturing a printed circuit board is provided, comprising: Performing an electroplating thickening treatment on a designated circuit network area of ​​a printed circuit board substrate to obtain a first preformed printed circuit board, wherein the printed circuit board substrate is a printed circuit board substrate manufactured according to a preset process, and the designated circuit network area is a pre-marked area where a current-carrying circuit network requiring internal resistance control is located; The first preformed printed circuit board is subjected to a layer-building process to obtain a completed printed circuit board.

[0006] In one embodiment, performing electroplating thickening treatment on the designated circuit network area of ​​the printed circuit board substrate to obtain a first preformed printed circuit board includes: a. sequentially stacking a conductive adhesive layer and a first copper foil layer on at least one surface of the printed circuit board substrate; b. bonding the printed circuit board substrate, the conductive adhesive layer, and the first copper foil layer together through a hot pressing process to obtain a first composite structure; c. performing a controlled-depth milling process on a designated circuit network area of ​​the first composite structure to expose a target copper layer on the printed circuit board substrate where a local thickened copper layer is to be formed; d. performing electroplating thickening treatment on the surface of the target copper layer to form a locally thickened copper layer; e. Removing the first copper foil layer and the conductive adhesive layer remaining on the surface of the first composite structure to obtain the first preformed printed circuit board.

[0007] In one embodiment, the controlling depth milling process on the designated circuit network area of ​​the first composite structure to expose the target copper layer on the printed circuit board substrate where the locally thickened copper layer is to be formed comprises: Performing one or more controlled-depth milling processes on a designated circuit network area of ​​the first composite structure according to a milling trajectory and depth parameters to expose a target copper layer in an area on the printed circuit board substrate where a locally thickened copper layer is to be formed; The milling trajectory is a path predetermined according to the shape and size of the designated circuit network area, and the depth parameter is a parameter predetermined according to the thickness of the conductive adhesive layer and the first copper foil layer.

[0008] In one embodiment, removing the first copper foil layer and the conductive adhesive layer remaining on the surface of the first composite structure to obtain the first preformed printed circuit board includes: removing the first copper foil layer remaining on the surface of the first composite structure by chemical treatment or mechanical treatment to obtain a first-processed composite structure; A potassium permanganate solution or a sodium hydroxide solution of a preset concentration is used to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time to obtain a first preformed printed circuit board.

[0009] In one embodiment, the step of dissolving the conductive adhesive layer on the surface of the composite structure treated for the first time using a potassium permanganate solution or a sodium hydroxide solution with a preset concentration to obtain a first preformed printed circuit board includes: dissolving the conductive adhesive layer on the surface of the composite structure treated for the first time using a potassium permanganate solution or a sodium hydroxide solution with a preset concentration to obtain a composite structure treated for the second time; The composite structure subjected to the second treatment is subjected to plasma desmear treatment to obtain a first preformed printed circuit board.

[0010] In one embodiment, the step of performing a layer build-up process on the first preformed printed circuit board to obtain a completed printed circuit board includes: Performing a layer build-up process on the first preformed printed circuit board to obtain a second preformed printed circuit board; Repeat steps a to e on the second preformed printed circuit board to obtain a third preformed printed circuit board; Solder resist ink and topcoat are applied on the surface of the third preformed printed circuit board to obtain a completed printed circuit board, wherein the surface on which the solder resist ink and topcoat are applied is the same as the surface on which the conductive adhesive layer and the first copper foil layer are provided.

[0011] In one embodiment, the step of performing a layer build-up process on the first preformed printed circuit board to obtain a second preformed printed circuit board includes: A dielectric layer and a second copper foil layer are sequentially stacked on the surface of the first preformed printed circuit board, wherein the dielectric layer and the second copper foil layer are provided on the same surface as the conductive adhesive layer and the first copper foil layer; bonding the first preformed printed circuit board, the dielectric layer, and the second copper foil layer together through a hot pressing process to obtain a second composite structure; The second composite structure is subjected to drilling, electroplating and conductor circuit fabrication to obtain a second preformed printed circuit board.

[0012] In one embodiment, the thickness of the first copper foil layer is 5 μm-50 μm and / or the thickness of the conductive adhesive layer is 15 μm-100 μm; and / or, The thickness of the second copper foil layer is 5 μm-50 μm and / or the thickness of the dielectric layer is 15 μm-100 μm; and / or, The hot pressing process has a temperature of 75°C-125°C, a pressure of 1.0kgf / cm²-5.0kgf / cm², and a duration of 15 seconds-60 seconds.

[0013] In one embodiment, the height of the locally thickened copper layer is 15 μm-150 μm; and / or, The length and width of the locally thickened copper layer meet the following conditions: When the designated circuit network area corresponds to a pad, the length and width of the locally thickened copper layer meet the first condition; When the designated circuit network area corresponds to a circuit, the length and width of the locally thickened copper layer meet the second condition; The first condition is: 25% a≤L≤100% a, 25% b≤W≤100% b; The second condition is: L=x, 25% y≤W≤100% y; Wherein, L is the length of the locally thickened copper layer, W is the width of the locally thickened copper layer, a is the length of the pad, b is the width of the pad, x is the length of the circuit, and y is the width of the circuit.

[0014] In a second aspect, a printed circuit board is provided. The printed circuit board is manufactured using the method for manufacturing a printed circuit board described in the first aspect.

[0015] The beneficial effects of a technical solution provided by the present invention are as follows: by directional electroplating to thicken specific current-carrying circuit network areas, the current-carrying capacity and heat dissipation efficiency of local conductors are improved without increasing the number of circuit board layers as a whole, effectively avoiding the problem of signal crosstalk caused by insufficient spacing between adjacent circuits due to excessively thick copper layers. Compared with the traditional full-layer thickening solution, it reduces consumption and the number of lamination process cycles, achieving the goal of reducing production costs and improving production efficiency while ensuring the current-carrying capacity and heat dissipation performance of the printed circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 is a schematic diagram of a conventional printed circuit board in one embodiment of the present invention; Figure 2 is a flow chart of a method for manufacturing a printed circuit board in one embodiment of the present invention; Figure 3 is a schematic diagram of a printed circuit board substrate in one embodiment of the present invention; Figure 4 is a schematic diagram of configuring a conductive adhesive layer and a first copper foil layer in one embodiment of the present invention; Figure 5 is a schematic diagram of a first composite structure in one embodiment of the present invention; Figure 6 is a schematic diagram of a first composite structure after controlled deep milling processing in one embodiment of the present invention; Figure 7 is a schematic diagram of a first composite structure after electroplating thickening treatment in one embodiment of the present invention; Figure 8 is another intermediate processing diagram of the composite structure processed for the first time in one embodiment of the present invention; Figure 9 is a schematic diagram of a first preformed printed circuit board according to an embodiment of the present invention; Figure 10This is a schematic diagram of configuring a dielectric layer and a second copper foil layer in one embodiment of the present invention; Figure 11 is a schematic diagram of a second composite structure in one embodiment of the present invention; Figure 12 is a schematic diagram of the second composite structure after drilling in one embodiment of the present invention; Figure 13 is a schematic diagram of a second composite structure after electroplating in one embodiment of the present invention; Figure 14 is a schematic diagram of a second preformed printed circuit board according to an embodiment of the present invention; Figure 15 is a schematic diagram of a third preformed printed circuit board according to an embodiment of the present invention; Figure 16 FIG. 1 is a schematic diagram of a manufactured printed circuit board according to an embodiment of the present invention.

[0018] The reference numerals are as follows: 1-PCB substrate; 2A-first conductive adhesive layer; 2B-second conductive adhesive layer; 3A-first copper foil layer; 3B-first second copper foil layer; 4A-first dielectric layer; 4B-second dielectric layer; 5A-second first copper foil layer; 5B-second second copper foil layer; 6-solder mask ink; X-specified circuit network area; Y-locally thickened copper layer; Z-drilling position DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] To facilitate understanding of the embodiments of the present invention, the prior art and related concepts involved in the present invention are first introduced as follows.

[0021] like Figure 1 As shown, the existing printed circuit board cannot meet the current carrying capacity and heat dissipation performance of the printed circuit board. Other methods used to improve the current carrying capacity and heat dissipation performance of the printed circuit board include: The first method uses high thermal conductivity insulating materials as dielectric layer materials. When reducing the thickness of the conductor layer (copper layer), the thermal conductivity requirements can be met to a certain extent. However, the adhesion of high thermal conductivity insulating materials is low, and there is a risk of peeling off during high-density wiring.

[0022] The second method is to embed a metal matrix or ceramic block in the printed circuit board, which not only involves complex machining and heterogeneous material combining processes, but also has high manufacturing costs.

[0023] The above methods also fail to achieve the technical effect of reducing production costs and improving production efficiency while ensuring the current carrying capacity and heat dissipation performance of the printed circuit board.

[0024] The terms involved in the present invention are introduced as follows: Printed Circuit Board (PCB), also known as printed circuit board, is an important electronic component. It is the support body of electronic components and the carrier of electrical connection of electronic components.

[0025] Substrate, also known as package substrate, is a type of printed circuit board. Compared with conventional printed circuit boards, it has higher wiring density, smaller overall thickness and higher precision.

[0026] The dielectric layer in the printed circuit board plays an insulating role, including but not limited to epoxy resin, polyimide, BT, ABF and ceramic base.

[0027] Prepreg, also known as PP sheet, includes but is not limited to epoxy resin, polyimide, BT, ABF and ceramic base types. It is one of the main materials in the production of multi-layer boards. It is mainly composed of resin and reinforcement materials. The reinforcement materials are divided into several types such as glass fiber cloth, paper base, and composite materials. The prepreg (bonding sheet) used in the production of multi-layer printed circuit boards mostly uses glass fiber cloth as the reinforcement material. After the prepreg is pressed and cured, it is called the insulating dielectric layer or insulating interlayer.

[0028] Laser drilling uses a high-power density laser beam to irradiate a specific material, causing the material to quickly heat to its vaporization temperature and evaporate to form a hole, which is called laser drilling.

[0029] Micro blind holes are processed by laser drilling and are conductive holes that connect two adjacent layers without penetrating them.

[0030] Conductive adhesive refers to a material primarily composed of silicone, epoxy, or polyimide adhesives, with silver, copper, or other conductive fillers added. Conductive adhesives, after curing or drying, possess a certain degree of conductivity and can connect multiple conductive materials, creating an electrical path between them. Examples include, but are not limited to, silver-based, gold-based, copper-based, and carbon-based adhesives. Silver-based adhesives are the most widely used.

[0031] In order to fully understand the present invention, please refer to Figures 2 to 16The following description provides detailed structures and steps to illustrate the technical solutions proposed by the present invention.

[0032] First, as Figure 2 and Figure 3 As shown, a method for manufacturing a printed circuit board is provided, comprising: S10. Performing an electroplating thickening treatment on a designated circuit network area X of a printed circuit board substrate 1 to obtain a first preformed printed circuit board, wherein the printed circuit board substrate 1 is a printed circuit board substrate 1 manufactured according to a preset process, and the designated circuit network area X is a pre-marked area where a current-carrying circuit network requiring internal resistance control is located.

[0033] In this embodiment, the current-carrying line network refers to the network area formed by the lines on the printed circuit board substrate 1 that have a specific current transmission task and require control of internal resistance, and their connections.

[0034] The designated circuit network area X is the electrical connection position or electrical connection area with external interconnected devices (including but not limited to chips and connectors) on the printed circuit board substrate 1, for example, the pad area for chip flip-chip bonding, the bonding point area for wire bonding, the pin contact area for connecting to the external connector, or the solder joint area for surface mount technology (SMT).

[0035] The designated line network area X can be determined by combining circuit simulation analysis with dedicated line marking software.

[0036] The preset process includes, but is not limited to, hole metallization and conductor line patterning. Specifically, the printed circuit board substrate 1 is a printed circuit board substrate 1 manufactured according to the preset process, that is, the original printed circuit board substrate 1 is subjected to hole metallization to form a metallized through-hole structure. For example, a process combining laser drilling or mechanical drilling with chemical copper plating is used to drill a preset through-hole position on the Lm+1-Ln+1 layer of the original printed circuit board substrate 1. A continuous and dense conductive copper layer is then formed on the hole wall by electroless deposition, thereby forming a metallized through-hole structure. Next, a conductor line patterning process is performed on the surface of the original printed circuit board that has undergone hole metallization to obtain a prepared printed circuit board substrate 1. For example, a conductor line patterning process is performed on the surface of the Lm+1-Ln+1 layer that has undergone metallized through-hole processing, for example, by selectively etching the excess copper layer through a photoresist mask to obtain the target line pattern, thereby obtaining a printed circuit board substrate 1 with a conductor line structure and metallized through-holes.

[0037] The thickness of the original printed circuit board substrate 1 can range from 0.1 mm to 5.0 mm, and preferably can be 0.5 mm, 1.0 mm, 2.0 mm, 3.0 mm, 3.5 mm, or 4.0 mm, without limitation herein. It should be understood that the shape and size of the original printed circuit board substrate 1 can be selected as needed and are not limited herein.

[0038] As an example, a designated circuit network area X of a printed circuit board substrate 1 is subjected to an electroplating thickening treatment. For example, the printed circuit board substrate 1 is placed in an electroplating tank and the designated circuit network area X is subjected to an electroplating thickening treatment, thereby obtaining a first preformed printed circuit board. Through this embodiment, the conductivity of the designated circuit network area X can be targeted and effectively reduced, thereby significantly improving the current carrying capacity of the printed circuit board, reducing losses during power transmission and heat generation, and optimizing local heat dissipation. For example, if the number of layers of the originally designed printed circuit board is 4, in order to meet the current carrying capacity and heat dissipation performance of the printed circuit board, the number of layers of the designed circuit board may be increased to 8, resulting in a doubling of material consumption and a decrease in processing efficiency. However, the present invention does not require increasing the number of layers of the printed circuit board. Instead, the electroplating thickening treatment is performed only on the designated circuit network area X of the originally designed printed circuit board. That is, the copper layer of the designated circuit network area X is electroplated to meet the current carrying capacity and heat dissipation performance of the printed circuit board. Therefore, the cost increase and low production efficiency caused by increasing the number of layers are effectively avoided.

[0039] S20: Performing a layer-building process on the first preformed printed circuit board to obtain a completed printed circuit board.

[0040] As an example, Figure 15 As shown, after the first preformed printed circuit board is produced, that is, after the Lm+1-Ln+1 layers of the printed circuit board are completed, further layer addition processing is required according to the predetermined number of printed circuit board layers. For example, if the predetermined number of printed circuit board layers is Lm+2-Ln+2, after the Lm+1-Ln+1 layers are completed, the Lm+2-Ln+2 layers need to be completed to obtain the completed printed circuit board. This embodiment not only achieves low internal resistance and high current carrying capacity due to thickening of the electroplating in the designated circuit network area X, but also ensures the layout of the signal and power layers of the originally designed printed circuit board, effectively overcoming the problems of increased material consumption and decreased production efficiency caused by increasing the number of layers.

[0041] It should be understood that if the pre-set printed circuit board is a multi-layer circuit board, the designated circuit network area X needs to be electroplated and thickened in each layer, so as to further improve the current carrying capacity and heat dissipation performance of the printed circuit board.

[0042] In summary, by directional electroplating to thicken specific current-carrying circuit network areas, the current-carrying capacity and heat dissipation efficiency of local conductors are improved without increasing the number of circuit board layers as a whole, effectively avoiding the signal crosstalk problem caused by insufficient spacing between adjacent circuits due to excessively thick copper layers. Compared with the traditional full-layer thickening solution, it reduces consumption by 40%-60% and the number of lamination process cycles by 30%-50%, achieving the goal of reducing production costs and improving production efficiency while ensuring the current-carrying capacity and heat dissipation performance of the printed circuit board.

[0043] In one embodiment, step S10, i.e., performing electroplating thickening treatment on the designated circuit network area X of the printed circuit board substrate 1 to obtain a first preformed printed circuit board, includes the following steps: a. A conductive adhesive layer and a first copper foil layer are sequentially stacked on at least one surface of the printed circuit board substrate 1.

[0044] In this embodiment, the conductive adhesive layer may be formed after the conductive adhesive is solidified, and the first copper foil layer may be an electrolytic copper foil or a rolled copper foil, which is only used as an example here.

[0045] The conductive adhesive layer includes a first conductive adhesive layer 2A and a second conductive adhesive layer 2B, and the first copper foil layer includes a first-first copper foil layer 3A and a first-second copper foil layer 3B.

[0046] As an example, Figure 4 and Figure 5 As shown, a conductive adhesive layer and a first copper foil layer are sequentially stacked on at least one surface of the printed circuit board substrate 1, that is, a conductive adhesive layer and a first copper foil layer are sequentially stacked on the first surface and / or the second surface of the printed circuit board substrate 1, including: providing a first conductive adhesive layer 2A on the first surface of the printed circuit board substrate 1, and providing a first copper foil layer 3A on the first conductive adhesive layer 2A; and / or providing a second conductive adhesive layer 2B on the second surface of the printed circuit board substrate 1, and providing a first copper foil layer 3B on the second conductive adhesive layer 2B.

[0047] The first conductive adhesive layer 2A can be applied to the first surface (e.g., Lm+1 surface) of the printed circuit board substrate 1 by a coating process (including but not limited to blade coating, roller coating, inkjet printing, or slot coating), and the second conductive adhesive layer 2B can also be applied to the second surface (e.g., Ln+1 surface) of the printed circuit board substrate 1 by a coating process. Subsequently, the surface of the first copper foil layer in contact with the conductive adhesive layer is roughened (with a roughness Rz of 2μm-8μm, preferably 3μm or 6μm) and then laminated onto the surface of the conductive adhesive layer. Specifically, a first copper foil layer 3A can be provided on the first conductive adhesive layer 2A, and a first second copper foil layer 3B can be provided on the second conductive adhesive layer 2B. In this embodiment, since the conductive adhesive layer is adhesive, by first applying the conductive adhesive layer and then applying the first copper foil layer thereon, dust contamination during the manufacturing process can be effectively prevented, significantly improving the yield rate of subsequent processes.

[0048] b. Bonding the printed circuit board substrate 1, the conductive adhesive layer and the first copper foil layer into one body through a hot pressing process to obtain a first composite structure.

[0049] In this embodiment, the temperature range of the hot pressing process can be 75°C-125°C. Within this temperature range, the conductive adhesive layer can be fully softened and exert its bonding properties without causing thermal damage to the glass substrate or the copper foil layer. The pressure range can be 1.0kgf / cm²-5.0kgf / cm². Within this pressure range, it can ensure that the layers of the composite structure are in full contact and exclude trapped bubbles, thereby improving the overall structural strength and electrical continuity. The duration range can be 15 seconds-60 seconds. Within this pressure range, the conductive adhesive layer can be cured and stress released, avoiding problems such as weak bonding, delamination or warping due to uneven pressing or insufficient time.

[0050] Preferably, the temperature of the hot pressing process can be 90°C, 100°C, 110°C or 120°C, the pressure of the hot pressing process can be 2.0kgf / cm², 3.0kgf / cm² or 4.0kgf / cm², and the duration of the hot pressing process can be 25 seconds, 35 seconds or 45 seconds.

[0051] As an example, Figure 5As shown, taking a 100μm-thick printed circuit board substrate 1 with a number of layers (Lm+1-Ln+1) as an example, a hot pressing process at 100°C, a pressure of 3.0 kgf / cm², and a duration of 35 seconds can be used to bond the printed circuit board substrate 1, the conductive adhesive layer, and the first copper foil layer together to form a first composite structure. The process results: The conductive adhesive layer completely impregnates the roughened surface of the first copper foil layer, achieving an interlayer peel strength of 1.2 N / mm, a 40% improvement compared to room-temperature lamination. The bubble residual rate is less than 0.5%, and the surface flatness of the first composite structure is ≤5μm. Experiments have demonstrated that the hot pressing process can achieve high-strength bonding (peel strength increased by 30%-50%), low defect rate (bubble rate less than 1%), and excellent electrical performance in the first composite structure under different scenarios, improving interlayer bonding strength.

[0052] c. Performing a controlled-depth milling process on the designated circuit network area X of the first composite structure to expose the target copper layer in the area where the locally thickened copper layer Y is to be formed on the printed circuit board substrate 1 .

[0053] In this embodiment, the target copper layer is an area on the printed circuit board substrate 1 corresponding to the designated circuit network area X.

[0054] The shapes of the designated circuit network area X and the target copper layer match the contact interface of the external interconnection device, including but not limited to circular, rectangular or other shapes.

[0055] As an example, Figure 6 As shown, laser processing, CNC processing, or other processing methods can be used to perform controlled-depth milling on the designated circuit network area X of the composite structure. Laser processing includes but is not limited to UV laser processing and CO2 laser processing, and CNC processing includes but is not limited to mechanical processing and water jet processing. That is, UV laser processing, CO2 laser processing, mechanical processing, or water jet processing can be used to perform controlled-depth milling on the designated circuit network area X of the first composite structure to expose the target copper layer in the area where the locally thickened copper layer Y is to be formed on the printed circuit board substrate 1. Through UV laser processing, CO2 laser processing, mechanical processing, or water jet processing, full coverage is achieved from micron-level chip pads to millimeter-level connector areas, forming technical advantages in precision, efficiency, and material compatibility, providing a clean, flat, and well-conductive target area for subsequent electroplating deposition, and improving manufacturing yield.

[0056] Specifically, the UV laser processing parameter range can be a wavelength of 200nm-400nm, a pulse frequency of 10kHz-100kHz, and a power of 5W-50W. Preferably, the wavelength can be 300nm or 350nm, the pulse frequency can be 50kHz or 70kHz, and the power can be 20W or 35W. The CO2 laser processing parameter range can be a wavelength of 9μm-11μm, a continuous wave mode, a power of 20W-200W. Preferably, the wavelength can be 10μm or 10.5μm, and the power can be 100W or 150W. The machining parameter range can be a spindle speed of 10000-50000 RPM, a feed rate of 100-1000 mm / min, a cutting depth of 0.05-0.5mm / layer, and a tool diameter of 0.1-3.0mm. Preferably, the spindle speed can be 20000 RPM or 30000 RPM, a feed rate of 300mm / min or 500 The water jet machining parameters may range from a water pressure of 300 MPa to 600 MPa, and an abrasive grit size of 200 to 800 mesh. Preferably, the water pressure may be 400 MPa or 500 MPa, and the abrasive grit size may be 300 mesh or 600 mesh. It should be understood that the above parameter ranges and preferred values ​​are merely illustrative and may be adjusted in practice based on the specific material being machined. These parameters do not constitute limitations of the present invention.

[0057] d. Performing electroplating thickening treatment on the surface of the target copper layer to form a locally thickened copper layer Y.

[0058] As an example, Figure 7 As shown, electroplating can be used to locally thicken the copper layer Y on surfaces where the target copper layer has been exposed. Specifically, the composite structure, which has undergone controlled-depth milling, can be placed in an electroplating tank. The electrolyte can be an acidic copper electroplating solution containing copper sulfate, sulfuric acid, and appropriate additives (such as brighteners and levelers) to ensure good adhesion and uniformity of the plated layer. After connecting to a DC power supply, the target copper layer serves as the cathode, and a high-purity copper plate is used as the anode. The current is used to reduce and deposit copper ions in the designated circuit network area X. In order to ensure the local thickening effect and the uniformity of the deposited copper layer, the expected thickness can be achieved by controlling the current density (for example, set within the range of 1.0A / dm²-3.0A / dm², preferably 1.5A / dm² or 2.0A / dm²) and the plating time (for example, set within the range of 30 seconds-90 seconds, preferably 50 seconds, 60 seconds or 70 seconds) during electroplating deposition. At the same time, the temperature and stirring speed in the electroplating tank can be precisely controlled to prevent the occurrence of local concentration differences.

[0059] To illustrate with a specific example: an electrolyte consisting of 0.5M copper sulfate and 0.5M sulfuric acid can be selected. Under the conditions of a set current density of 2.0A / dm², a temperature maintained at 25°C, and a stirring speed of approximately 300 rpm, after 60 seconds of electroplating, a copper layer with a thickness of approximately 50μm can be deposited in the designated circuit network area X. During the entire electroplating deposition process, since deposition is only performed on the designated circuit network area X that has been exposed after the controlled depth milling process, unnecessary redundant deposition in other areas is avoided, thereby achieving the precision requirements of local thickening. Through this embodiment, the problem of difficult to accurately control the thickness of the local copper layer in traditional processes is effectively compensated, further ensuring the stability of electrical contact and heat dissipation performance in subsequent processes, and providing a solid foundation for improving the performance of high-end electronic devices.

[0060] e. Removing the first copper foil layer and the conductive adhesive layer remaining on the surface of the first composite structure to obtain the first preformed printed circuit board.

[0061] As an example, Figure 8 and Figure 9 As shown, removing the remaining first copper foil layer and the conductive adhesive layer on the surface of the first composite structure can be understood as removing the first copper foil layer and the conductive adhesive layer in the area where the copper layer Y does not need to be locally thickened (i.e., the first copper foil layer and the conductive adhesive layer except for the target copper layer and the electroplated thickened portion thereof).

[0062] Specifically, the remaining first copper foil layer on the surface of the first composite structure can be removed first, followed by the remaining conductive adhesive layer on the composite structure, thereby obtaining a glass substrate with a locally thickened copper layer Y. The first preformed printed circuit board obtained through this embodiment not only has a locally thickened copper layer Y, but also has clean, residue-free non-functional areas, meeting the stringent reliability and precision requirements of high-end electronic packaging. Compared to traditional simultaneous removal processes, the phased approach offers significant advantages in accuracy, reliability, and efficiency, making it particularly suitable for the manufacture of advanced printed circuit boards such as high-density, ultra-thin, and flexible ones.

[0063] In one embodiment, step c, i.e., performing a controlled depth milling process on the designated circuit network area X of the first composite structure to expose the target copper layer in the area where the locally thickened copper layer Y is to be formed on the printed circuit board substrate 1, comprises the following steps: c1. Performing one or more controlled-depth milling processes on the designated circuit network area X of the first composite structure according to the milling trajectory and depth parameters to expose the target copper layer in the area where the locally thickened copper layer Y is to be formed on the printed circuit board substrate 1; The milling trajectory is a path predetermined according to the shape and size of the designated circuit network area X, and the depth parameter is a parameter predetermined according to the thickness of the conductive adhesive layer and the first copper foil layer.

[0064] In this embodiment, the preset milling trajectory is a path predetermined based on the shape and size of the designated circuit network area X. That is, the path data is pre-planned based on the shape (circular, rectangular, or other shape) and size of the designated circuit network area X, and computer-aided design (CAD) software can be used to generate the path data. For example, if the designated circuit network area X is a rectangle, the milling trajectory can be generated using computer-aided design (CAD) software to create a straight path that matches the rectangle based on the boundaries and dimensions of the rectangle. If the designated circuit network area X is a circle, the milling trajectory can be determined as a circular path based on the center and radius of the circle, thereby performing precise milling within the area.

[0065] The preset depth parameter is a parameter predetermined based on the thickness of the conductive adhesive layer and the copper foil layer. For example, if the thickness of the copper foil layer is 10 μm and the thickness of the conductive adhesive layer is 50 μm, the preset depth parameter may be 60 μm. Here, the setting of the preset depth parameter only needs to ensure that the target copper layer of the specified circuit network area X on the printed circuit board substrate 1 is not penetrated.

[0066] As an example, Figure 6 As shown, during the milling process, the processing method and processing parameters described in the embodiment of step c can be used to perform one or more milling on the conductive adhesive layer and copper foil layer of the specified circuit network area X. For example, if the thickness of the copper foil layer in the composite structure is 25μm and the thickness of the conductive adhesive layer is 60μm, and the target copper layer is at a depth of 85μm from the surface of the first composite structure, the preset depth parameter of the depth-controlled milling can be set to 85μm, and two milling methods are used: the first rough milling to 80μm, and the second fine milling to the final depth of 85μm. During the milling process, the milling depth deviation can be calibrated through real-time detection and feedback to ensure that the surface of the target copper layer is completely exposed. Through this embodiment, not only the problem of local removal that is difficult to achieve with traditional etching is avoided, but also the process flexibility and consistency of the thickened area are significantly improved.

[0067] In one embodiment, step e, i.e., removing the first copper foil layer and the conductive adhesive layer remaining on the surface of the first composite structure to obtain the first preformed printed circuit board, includes the following steps: e1. removing the first copper foil layer remaining on the surface of the first composite structure by chemical treatment or mechanical treatment to obtain a first-treated composite structure; e2. Using a potassium permanganate solution or a sodium hydroxide solution of a preset concentration to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time, to obtain a first preformed printed circuit board.

[0068] In this embodiment, chemical treatment refers to removing the remaining first copper foil layer on the surface of the first composite structure by chemical etching (for example, an acidic ferric chloride solution with a concentration of 15%-25% and an etching rate of 8μm / min-15μm / min, preferably, the acidic ferric chloride solution with a concentration of 18% or 22% and an etching rate of 10μm / min or 13μm / min); mechanical treatment refers to polishing and removing the remaining first copper foil layer on the surface of the first composite structure by using a ceramic brush, a flattening brush, or a non-woven brush (for example, a pressure of 0.01MPa-0.3MPa and a linear speed of 10m / min-20m / min, preferably, a pressure of 0.1MPa or 0.2MPa and a linear speed of 14m / min or 18m / min). It should be understood that chemical treatment is applicable to copper foil layers of 5μm-20μm, and mechanical treatment is applicable to copper foil layers of 20μm-50μm.

[0069] A potassium permanganate solution or a sodium hydroxide solution of a preset concentration is used to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time. That is, a potassium permanganate solution of a first preset concentration can be used to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time, or a sodium hydroxide solution of a second preset concentration can be used to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time. The first preset concentration can be in the range of 5%-15%, preferably 8% or 11%; the second preset concentration can be in the range of 1%-10%, preferably 5% or 8%. The specific range can be configured as needed and is only used as an example. By limiting the concentration range of the potassium permanganate solution and the sodium hydroxide solution, the conductive adhesive layer can be completely dissolved without damaging the printed circuit board. This is because a potassium permanganate concentration of less than 5% will not dissolve completely, while a concentration greater than 15% will cause oxidation damage to the printed circuit board. A sodium hydroxide concentration of less than 1% is too inefficient, while a concentration greater than 10% will corrode the first copper foil layer.

[0070] As an example, Figure 8 and Figure 9 As shown, first, the first copper foil layer on the surface of the first composite structure can be removed by chemical etching or mechanical means. The composite structure after the first treatment is then further treated with a potassium permanganate solution or sodium hydroxide solution of a preset concentration to dissolve the remaining conductive adhesive layer. For example, immersion in a 5% potassium permanganate solution at 60°C for 10 minutes, or spraying with a 3% sodium hydroxide solution at room temperature for 5 minutes, can be performed. In actual operation, if the conductive adhesive layer is 60μm thick, ultrasonic assistance can be used to improve the dissolution efficiency and ultimately completely remove the remaining conductive adhesive layer, thereby obtaining a first preformed printed circuit board, retaining the locally thickened copper layer Y located on the original target copper layer.

[0071] In one embodiment, step e2, i.e., using a potassium permanganate solution or a sodium hydroxide solution of a predetermined concentration to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time to obtain a first preformed printed circuit board, includes the following steps: e21. Dissolving the conductive adhesive layer on the surface of the composite structure treated for the first time using a potassium permanganate solution or a sodium hydroxide solution with a preset concentration to obtain a composite structure treated for the second time; e22. Perform plasma desmear treatment on the composite structure subjected to the second treatment to obtain a first preformed printed circuit board.

[0072] As an example, Figure 9 As shown, after the conductive adhesive layer on the surface of the composite structure treated for the first time is dissolved by using a potassium permanganate solution or a sodium hydroxide solution of a preset concentration, a composite structure treated for the second time with very little residual contamination can be obtained; further, the composite structure treated for the second time obtained by the dissolution needs to be subjected to a plasma decontamination treatment, for example, oxygen plasma and / or argon plasma is used to clean the surface of the composite structure treated for the second time. Specifically, oxygen (purity ≥ 95%) can be used, with a power of 100W-300W and a treatment time of 30 seconds-60 seconds. Preferably, the power can be 180W or 250W, and the treatment time can be 40 seconds. Alternatively, a mixed gas of oxygen and / or argon (flow ratio 1:1-3:1) may be used, with a power of 100W-300W and a treatment time of 30 seconds-90 seconds. Preferably, the power may be 180W or 250W, and the treatment time may be 40 seconds, 50 seconds, 60 seconds, 70 seconds, or 80 seconds. Alternatively, argon (purity ≥ 95%) may be used, with a power of 50W-150W and a treatment time of 15 seconds-30 seconds. Alternatively, the power may be 100W or 130W, and the treatment time may be 20 seconds or 25 seconds, to remove the conductive adhesive residue on the hole wall and the corner of the composite structure treated for the second time (the residual rate of particles with a particle size greater than 5μm is less than 0.05%), so that the amount of organic matter residue on the surface of the first preformed printed circuit board and the inner wall of the through-hole is ≤0.01μg / cm², and the surface roughness Ra is ≤1.0μm. Through this embodiment, step e21 dissolves and removes 80%-90% of the conductive adhesive layer, and step e22 plasma treatment removes the remaining 10%-20% of stubborn residues and drill contamination, with a total removal rate of ≥99.99%. This not only removes extremely small amounts of organic adhesive residues, but also effectively removes particulate contaminants that may be introduced during milling, electroplating, or chemical treatment, ensuring that the first preformed printed circuit board is ultimately obtained. This is suitable for microelectronic packaging or high-reliability integrated circuit manufacturing scenarios with high cleanliness requirements.

[0073] In one embodiment, if Figure 15 and Figure 16As shown, in step S20, that is, performing a layer-building process on the first preformed printed circuit board to obtain a completed printed circuit board, the following steps are included: S21, performing a layer-building process on the first preformed printed circuit board to obtain a second preformed printed circuit board; S22, repeating steps a to e for the second preformed printed circuit board to obtain a third preformed printed circuit board; S23 , applying solder resist ink 6 and surface coating on the surface of the third preformed printed circuit board to obtain a completed printed circuit board.

[0074] As an example, a first preformed printed circuit board that has been subjected to electroplating and thickening treatment and whose performance has reached the preset requirements can be subjected to a layer-building treatment to obtain a second preformed printed circuit board; next, the aforementioned layer-building treatment steps a to e are repeatedly performed on the obtained second preformed printed circuit board. For the specific implementation process, please refer to the description of the embodiment of the aforementioned steps a to e, which will not be repeated here to avoid repetition, thereby obtaining a third preformed printed circuit board; finally, as shown in FIG. Figure 16 As shown, the surface of the third preformed printed circuit board is sprayed with solder resist ink 6 and subjected to a surface coating process to form a protective layer to prevent the copper layer of the manufactured printed circuit board from being corroded by chemicals in the environment. In this way, a completed printed circuit board is obtained, which improves the overall heat dissipation and mechanical protection performance, ensures the low resistance performance of the current-carrying area, and realizes the optimized wiring of the signal and power layers, effectively overcoming the problems of increased material consumption and insufficient process stability caused by the layer-building process.

[0075] It should be understood that the above steps S21 to S22 can be repeated for multiple layers, depending on the number of layers of the pre-set printed circuit board. Here, only a printed circuit board with Lm+2-Ln+1 layers is taken as an example, which does not constitute a limitation of the present invention.

[0076] In one embodiment, if Figure 10 and Figure 11 As shown, step S21, that is, performing a layer-building process on the first preformed printed circuit board to obtain a second preformed printed circuit board, includes the following steps: S211. A dielectric layer and a second copper foil layer are sequentially stacked on the surface of the first preformed printed circuit board, wherein the surface where the dielectric layer and the second copper foil layer are provided is the same as the surface where the conductive adhesive layer and the first copper foil layer are provided.

[0077] In this embodiment, the dielectric layer includes but is not limited to an adhesive sheet, a prepreg, or other materials, and the second copper foil layer may be an electrolytic copper foil or a rolled copper foil, which are only used as examples here.

[0078] The surfaces on which the dielectric layer and the second copper foil layer are provided are the same as the surfaces on which the conductive adhesive layer and the first copper foil layer are provided. This means that when the conductive adhesive layer and the first copper foil layer are sequentially stacked on the first surface and / or the second surface of the printed circuit board substrate 1, the dielectric layer and the second copper foil layer are correspondingly stacked on the first surface and / or the second surface of the first preformed printed circuit board produced. For example, when the conductive adhesive layer and the first copper foil layer are sequentially stacked on the first surface of the printed circuit board substrate 1, the dielectric layer and the second copper foil layer are correspondingly stacked on the first surface of the first preformed printed circuit board produced. Here, it is sufficient to ensure that the surface of the printed circuit board substrate 1 undergoing the electroplating thickening treatment is the same as the surface undergoing the build-up layer.

[0079] The dielectric layer includes a second-first dielectric layer and a second-second dielectric layer, and the second copper foil layer includes a second-first copper foil layer 5A and a second-second copper foil layer 5B.

[0080] As an example, Figure 10 As shown, if a first conductive adhesive layer 2A is provided on the first surface (e.g., surface Lm+1) of the printed circuit board substrate 1, a first copper foil layer 3A is provided on the first conductive adhesive layer 2A, a second conductive adhesive layer 2B is provided on the second surface (e.g., surface Lm+1) of the printed circuit board substrate 1, and a first copper foil layer 3B is provided on the second conductive adhesive layer 2B, then a first dielectric layer 4A is provided on the first surface (e.g., surface Lm+1) of the first preformed printed circuit board, and a second copper foil layer 5A is provided on the first dielectric layer 4A, and a second copper foil layer 5B is provided on the second dielectric layer 4B. In this embodiment, by sequentially providing dielectric layers and copper foil layers on corresponding surfaces of the first preformed printed circuit board, a new layer corresponding to the original printed circuit board substrate 1 is constructed. This not only achieves a reasonable layout of signal and power layers, ensuring electrical performance, but also optimizes heat dissipation paths and improves the overall performance of the printed circuit board without excessively increasing material consumption.

[0081] It should be understood that the specific process of sequentially stacking the dielectric layer and the second copper foil layer on the surface of the first preformed printed circuit board can refer to the description of the aforementioned step a embodiment, and will not be repeated here to avoid repetition.

[0082] S212 , bonding the first preformed printed circuit board, the dielectric layer, and the second copper foil layer together through a hot pressing process to obtain a second composite structure.

[0083] In this embodiment, Figure 11As shown, the parameter definition of the hot pressing process can refer to the definition of the hot pressing parameters in the aforementioned step b embodiment. In addition, the specific process of step S212 can also refer to the description of the aforementioned step b embodiment. The only difference here is the bonding material. That is, step b is to bond the printed circuit board substrate 1, the conductive adhesive layer and the first copper foil layer into one by a hot pressing process, while step S212 is to bond the first preformed printed circuit board, the dielectric layer and the second copper foil layer into one by a hot pressing process. To avoid repetition, it will not be described here.

[0084] S213 , drilling, electroplating, and conductor circuit fabrication are performed on the second composite structure to obtain a second preformed printed circuit board.

[0085] As an example, after obtaining the second composite structure, that is, obtaining the printed circuit board after adding layers, that is, at this time, the number of layers of the second composite structure is Lm+2-Ln+2. Specifically, Figure 12 As shown, the second composite structure may be drilled (e.g., laser drilling or mechanical drilling) first, for example, the Lm+2-Ln+2 layer of the second composite structure is drilled, for example, the Lm+2-Ln+2 layer of the second composite structure is drilled at the drilling position Z. Then, as shown in FIG. Figure 13 As shown, the second composite structure after drilling is electroplated (hole electroplating), for example, the Lm+2-Ln+2 layer of the second composite structure after drilling is electroplated, for example, the electroplating is performed at the drilling position Z after drilling. Finally, as shown Figure 14 As shown, conductor circuits are fabricated on the second composite structure after electroplating. For example, conductor circuits are fabricated on the Lm+2-Ln+2 layers of the second composite structure after electroplating, thereby obtaining a second preformed printed circuit board.

[0086] In one embodiment, the thickness of the first copper foil layer is 5 μm-50 μm and / or the thickness of the conductive adhesive layer is 15 μm-100 μm. Specific values ​​can be selected based on actual application requirements. By limiting the thickness of the first copper foil layer and the conductive adhesive layer to the above ranges, a balance can be achieved between bonding reliability and subsequent processing accuracy.

[0087] Preferably, the thickness of the first copper foil layer may be 10 μm, 20 μm, 30 μm, 35 μm or 40 μm, and the thickness of the conductive adhesive layer may be 20 μm, 35 μm, 50 μm, 65 μm, 75 μm or 90 μm, which are only examples and do not constitute a limitation of the present invention.

[0088] In one embodiment, the thickness of the second copper foil layer is 5μm-50μm and / or the thickness of the dielectric layer is 15μm-100μm. Specific values ​​can be selected based on actual application requirements. Limiting the thickness of the second copper foil layer within this range ensures good electrical conductivity while flexibly adapting to different current carrying requirements. Limiting the thickness of the dielectric layer within this range effectively isolates the different conductive layers, reducing signal interference. Selecting the thickness based on actual requirements balances the performance, cost, and spatial layout of the printed circuit board, improving overall applicability.

[0089] Preferably, the thickness of the second copper foil layer may be 10 μm, 20 μm, 30 μm, 35 μm or 40 μm, and the thickness of the dielectric layer may be 20 μm, 35 μm, 50 μm, 65 μm, 75 μm or 90 μm, which are only examples and do not constitute a limitation of the present invention.

[0090] In one embodiment, the height of the locally thickened copper layer Y is 15 μm to 150 μm, with the specific value selected based on actual application requirements. By limiting the height of the locally thickened copper layer Y to the above range, the internal resistance of the circuit in the target area can be effectively reduced, enhancing conductivity, while also helping to improve local heat dissipation, thereby avoiding excessive local temperature rise caused by insufficient thickness or affecting subsequent process steps due to excessive thickness.

[0091] Preferably, the height of the locally thickened copper layer Y may be 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 110 μm, 130 μm or 140 μm, which is only used as an example and does not constitute a limitation to the present invention.

[0092] In one embodiment, the length and width of the locally thickened copper layer Y meet the following conditions: When the designated circuit network area X corresponds to a pad, the length and width of the locally thickened copper layer Y meet the first condition; When the designated circuit network area X corresponds to a circuit, the length and width of the locally thickened copper layer Y meet the second condition; The first condition is: 25% a≤L≤100% a, 25% b≤W≤100% b; The second condition is: L=x, 25% y≤W≤100% y; Wherein, L is the length of the locally thickened copper layer Y, W is the width of the locally thickened copper layer Y, a is the length of the pad, b is the width of the pad, x is the length of the circuit, and y is the width of the circuit.

[0093] As an example, according to different application scenarios, the size requirements of the local thickened copper layer Y are also divided accordingly: when the specified circuit network area X corresponds to the pad, the length L and width W of the local thickened copper layer Y should match the pad size, and the conditions to be met are: L should be between 25% and 100% of the pad length a, that is, 25% a≤L≤100% a, preferably, L can be between 40%-90% of the pad length a, i.e. 40% a≤L≤90% a; and W should be between 25%-100% of the pad width b, i.e. 25% b≤W≤100% b, preferably, W can be between 40%-90% of the pad width b, i.e. 40% b≤W≤90% b. When the designated line network area X corresponds to the line, the length L and width W of the local thickened copper layer Y should match the line size. The conditions to be met are: the length L of the local thickened copper layer Y is consistent with the length x of the line, that is, L=x, and the width W of the local thickened copper layer Y should be between 25%-100% of the line width y, that is, 25% y≤W≤100% y, preferably, W can be between 40% and 90% of the line width y, that is, 40% y≤W≤100% The aforementioned size-matching strategy not only helps ensure uniform and secure metal deposition in key areas during the electroplating thickening process, but also ensures stable electrical and mechanical connections at key current-carrying locations during subsequent interlayer interconnection and soldering. This organically combines low internal resistance with excellent heat dissipation, providing a solid guarantee for the overall performance of high-density wiring structures. It effectively addresses issues such as current concentration, uneven local heating, and insufficient process stability caused by size mismatch in traditional methods, optimizing current-carrying capacity while improving the production efficiency and reliability of printed circuit boards.

[0094] For example, on a printed circuit board, two different areas require local copper thickening: one corresponding to the pad and the other to the wiring. For the pad area, assuming a length a = 2.0mm and a width b = 1.2mm, according to the first condition, the length L of the locally thickened copper layer Y should satisfy 25% × 2.0mm ≤ L ≤ 100% × 2.0mm, or 0.5mm ≤ L ≤ 2.0mm, and the width W should satisfy 25% × 1.2mm ≤ W ≤ 100% × 1.2mm, or 0.3mm ≤ W ≤ 1.2mm. In practical applications, the dimensions of the locally thickened copper layer Y can be selected as L = 1.5mm and W = 1.0mm, while the thickness of the locally thickened copper layer is set to 60μm, which is within the range of 15μm-150μm. This effectively reduces the internal resistance of the pad area while providing sufficient electrical conductivity and heat dissipation. On the other hand, for the circuit area, assuming that the length x of the circuit is 2.0 mm and the width y is 0.8 mm, according to the second condition, the length L of the locally thickened copper layer Y should be equal to 2.0 mm, and the width W should satisfy 25% × 0.8 mm ≤ W ≤ 100% × 0.8 mm, that is, 0.2 mm ≤ W ≤ 0.8 mm. In this area, W = 0.6 mm can be selected as the width of the locally thickened copper layer Y, while L = 2.0 mm remains unchanged, and the thickening height is also set to 60 μm. It should be understood that the above parameters are only for the purpose of explaining this embodiment. The specific parameters are subject to actual conditions and do not constitute a limitation of the present invention.

[0095] In a second aspect, a printed circuit board is provided, wherein the printed circuit board is manufactured using the method for manufacturing a printed circuit board described in the first aspect.

[0096] In the description of the present invention, a plurality refers to two or more.

[0097] In the description of the present invention, the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0098] In the description of the present invention, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0099] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a printed circuit board, characterized in that: include: Performing an electroplating thickening treatment on a designated circuit network area of ​​a printed circuit board substrate to obtain a first preformed printed circuit board, wherein the printed circuit board substrate is a printed circuit board substrate manufactured according to a preset process, and the designated circuit network area is a pre-marked area where a current-carrying circuit network requiring internal resistance control is located; The first preformed printed circuit board is subjected to a layer-building process to obtain a completed printed circuit board.

2. The method for manufacturing a printed circuit board according to claim 1, wherein: The step of performing electroplating and thickening treatment on the designated circuit network area of ​​the printed circuit board substrate to obtain a first preformed printed circuit board comprises: a. sequentially stacking a conductive adhesive layer and a first copper foil layer on at least one surface of the printed circuit board substrate; b. bonding the printed circuit board substrate, the conductive adhesive layer, and the first copper foil layer together through a hot pressing process to obtain a first composite structure; c. performing a controlled-depth milling process on a designated circuit network area of ​​the first composite structure to expose a target copper layer on the printed circuit board substrate where a local thickened copper layer is to be formed; d. performing electroplating thickening treatment on the surface of the target copper layer to form a locally thickened copper layer; e. Removing the first copper foil layer and the conductive adhesive layer remaining on the surface of the first composite structure to obtain the first preformed printed circuit board.

3. The method for manufacturing a printed circuit board according to claim 2, wherein: The step of performing controlled-depth milling on the designated circuit network area of ​​the first composite structure to expose the target copper layer on the printed circuit board substrate where the locally thickened copper layer is to be formed comprises: Performing one or more controlled-depth milling processes on a designated circuit network area of ​​the first composite structure according to a milling trajectory and depth parameters to expose a target copper layer in an area on the printed circuit board substrate where a locally thickened copper layer is to be formed; The milling trajectory is a path predetermined according to the shape and size of the designated circuit network area, and the depth parameter is a parameter predetermined according to the thickness of the conductive adhesive layer and the first copper foil layer.

4. The method for manufacturing a printed circuit board according to claim 2, wherein: The step of removing the first copper foil layer and the conductive adhesive layer remaining on the surface of the first composite structure to obtain the first preformed printed circuit board includes: removing the first copper foil layer remaining on the surface of the first composite structure by chemical treatment or mechanical treatment to obtain a first-processed composite structure; A potassium permanganate solution or a sodium hydroxide solution of a preset concentration is used to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time to obtain a first preformed printed circuit board.

5. The method for manufacturing a printed circuit board according to claim 4, wherein: The method of using a potassium permanganate solution or a sodium hydroxide solution of a preset concentration to dissolve the conductive adhesive layer on the surface of the composite structure treated for the first time to obtain a first preformed printed circuit board comprises: dissolving the conductive adhesive layer on the surface of the composite structure treated for the first time using a potassium permanganate solution or a sodium hydroxide solution with a preset concentration to obtain a composite structure treated for the second time; The composite structure subjected to the second treatment is subjected to plasma desmear treatment to obtain a first preformed printed circuit board.

6. The method for manufacturing a printed circuit board according to any one of claims 2 to 5, characterized in that: The step of performing a layer-building process on the first preformed printed circuit board to obtain a completed printed circuit board includes: Performing a layer build-up process on the first preformed printed circuit board to obtain a second preformed printed circuit board; Repeat steps a to e on the second preformed printed circuit board to obtain a third preformed printed circuit board; Solder resist ink and topcoat are applied on the surface of the third preformed printed circuit board to obtain a completed printed circuit board, wherein the surface on which the solder resist ink and topcoat are applied is the same as the surface on which the conductive adhesive layer and the first copper foil layer are provided.

7. The method for manufacturing a printed circuit board according to claim 6, wherein: The step of performing a layer-building process on the first preformed printed circuit board to obtain a second preformed printed circuit board includes: A dielectric layer and a second copper foil layer are sequentially stacked on the surface of the first preformed printed circuit board, wherein the dielectric layer and the second copper foil layer are provided on the same surface as the conductive adhesive layer and the first copper foil layer; bonding the first preformed printed circuit board, the dielectric layer, and the second copper foil layer together through a hot pressing process to obtain a second composite structure; The second composite structure is subjected to drilling, electroplating and conductor circuit fabrication to obtain a second preformed printed circuit board.

8. The method for manufacturing a printed circuit board according to claim 7, wherein: The thickness of the first copper foil layer is 5 μm-50 μm and / or the thickness of the conductive adhesive layer is 15 μm-100 μm; and / or, The thickness of the second copper foil layer is 5 μm-50 μm and / or the thickness of the dielectric layer is 15 μm-100 μm; and / or, The hot pressing process has a temperature of 75°C-125°C, a pressure of 1.0kgf / cm²-5.0kgf / cm², and a duration of 15 seconds-60 seconds.

9. The method for manufacturing a printed circuit board according to any one of claims 2 to 5, characterized in that: The height of the locally thickened copper layer is 15 μm-150 μm; and / or, The length and width of the locally thickened copper layer meet the following conditions: When the designated circuit network area corresponds to a pad, the length and width of the locally thickened copper layer meet the first condition; When the designated circuit network area corresponds to a circuit, the length and width of the locally thickened copper layer meet the second condition; The first condition is: 25% a≤L≤100% a, 25% b≤W≤100% b; The second condition is: L=x, 25% y≤W≤100% y; Wherein, L is the length of the locally thickened copper layer, W is the width of the locally thickened copper layer, a is the length of the pad, b is the width of the pad, x is the length of the circuit, and y is the width of the circuit.

10. A printed circuit board, characterized in that: The printed circuit board is manufactured by the method for manufacturing a printed circuit board according to any one of claims 1 to 9.

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