High-copper-thickness PCB (Printed Circuit Board) and manufacturing method thereof

Abstract

The invention discloses a high-copper-thickness PCB and a manufacturing method thereof, and the method comprises the steps: manufacturing an inner-layer circuit with the copper thickness not less than 3 ounces on a substrate through employing a subtractive method, obtaining an inner-layer core board, and employing a two-stage etching technology for the etching processing in the subtractive method; after the inner-layer core board is coarsened, a resin layer is printed on at least one side, provided with the inner-layer circuit, of the inner-layer core board, and a composite printing technology combining primary printing, pre-baking, secondary printing and baking curing is adopted for printing; the inner layer circuit and the resin layer are leveled, so that the outer surface of the inner layer circuit is not covered by the resin layer while the inner layer circuit and the resin layer are flush with each other in thickness; and placing the insulating added layer and the added layer copper foil layer on the inner layer circuit in a stacking manner, and performing lamination to obtain the intermediate plate. The manufacturing method is reasonable, simple and easy to operate, the obtained high-copper-thickness PCB has the advantages of being good in structural stability, high in circuit pattern thickness, high in precision, good in quality and the like, and the market requirements of large-current and high-power electronic products are met.

Description

Technical Field

[0001] This invention relates to the field of circuit board technology, and in particular to a high-copper-weight PCB board and its manufacturing method. Background Technology

[0002] As electronic products evolve towards higher current and higher power, the copper thickness of the inner layers of PCBs is also increasing to meet demands such as efficient heat dissipation. Currently, PCBs with inner layer copper thickness of 3 ounces or more have gradually become the mainstream products in the market.

[0003] However, the manufacturing process of high-copper-thickness PCBs presents the following technical challenges: ① When using subtractive etching to fabricate inner layer circuitry, the increased copper thickness necessitates longer etching times. During this prolonged etching process, the etching solution not only etches the copper layer vertically but also severely erodes the sidewalls of the circuit pattern horizontally, resulting in significantly reduced linewidth and suboptimal quality of the inner layer circuitry. ② Due to the thick copper content of the inner layer circuitry, the molten prepreg cannot completely fill the gaps between the circuits (i.e., copper-free areas) during subsequent lamination processes. This leads to defects such as insufficient filler and weak interlayer bonding after lamination, severely impacting the quality of the PCB.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] To overcome the above-mentioned defects, the present invention provides a high copper thickness PCB board and its manufacturing method. The manufacturing method is reasonable, simple and easy to operate and implement. The resulting high copper thickness PCB board has the advantages of good overall structural stability, high thickness and high precision of circuit patterns, and good quality, which well meets the market demand for high current and high power electronic products.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for manufacturing a high-copper-weight PCB board, comprising: An inner layer circuit with a copper thickness of not less than 3 ounces is fabricated on a substrate using a subtractive process to obtain an inner layer core board; wherein, the etching process in the above subtractive process adopts a two-stage etching process, and the ratio between the etching amount of the first etching process and the etching amount of the second etching process is (1.1~2):1. After roughening the inner core board, a resin layer is printed on at least one side of the inner core board where the inner layer circuit is located; wherein, the printing adopts a composite printing process combining one-time printing, pre-baking, two-time printing and baking curing, and the resin layer protrudes outside the inner layer circuit. The inner layer circuit and the resin layer are leveled so that the inner layer circuit and the resin layer are of equal thickness and flush, while the outer surface of the inner layer circuit is not covered by the resin layer. An insulating layer and an additional copper foil layer are stacked on the inner layer circuitry and laminated together to obtain an intermediate board.

[0007] As a further improvement of the present invention, in the two etching processes described above, the raw material composition of the acidic etching solution is the same, as are the etching temperature and etching transfer speed. In addition, the ratio between the etching amount of the first etching process and the etching amount of the second etching process is (1.5~2):1.

[0008] As a further improvement of the present invention, the concentration of sodium chlorate in the acidic etching solution is 30-40 mol / L, the concentration of hydrochloric acid is 2-2.5 mol / L, and the concentration of copper ions is 130-150 g / L; In the two etching processes described above, the etching temperature was 48℃~52℃, the etching conveyor speed was 3~5m / min, and the upper spray pressure was 1.5~3Kgf / cm. 2 The spray pressure is 1.5–2.5 kgf / cm². 2 .

[0009] As a further improvement of the present invention, the glass transition temperature, coefficient of thermal expansion and dielectric constant of the resin layer and the insulating layer are the same or similar.

[0010] As a further improvement of the present invention, the insulating layer is a prepreg, and the resin layer is any one of epoxy resin, polyimide resin and BT resin.

[0011] As a further improvement of the present invention, the method of printing the resin layer on at least one side of the inner core board where the inner layer circuit is provided is as follows: Create a negative screen printing plate corresponding to the inner layer circuitry; First, a first layer of resin of a set thickness is printed on at least one side of the inner core board with the inner layer circuit using a screen printing machine equipped with the negative screen. Then, the first layer of resin is pre-baked at a temperature of 115°C to 125°C for 10 to 15 minutes. Next, a second layer of resin is printed on the inner core board with the inner layer circuit using the screen printing machine. Then, the two layers of resin are baked until they are completely cured to obtain the resin layer.

[0012] As a further improvement of the present invention, the thickness h of the first resin layer and the copper thickness H of the inner layer circuit satisfy the following relationship: h = H × (30% ~ 70%).

[0013] As a further improvement of the present invention, the inner core board is roughened by a browning or blackening process; the inner circuit and the resin layer are leveled by a ceramic grinding plate.

[0014] As a further improvement of the present invention, depending on the characteristics of the added copper foil, the outer layer circuitry can be fabricated selectively using a subtractive process or mSAP process.

[0015] The present invention also provides a high copper thickness PCB board, which is manufactured using the high copper thickness PCB board manufacturing method described in the present invention.

[0016] The beneficial effects of this invention are as follows: Compared with the prior art, this application improves and innovates the manufacturing method of high-copper-thickness PCB boards. ① It adopts a two-stage etching process of "etching away most of the copper first, and then etching away the remaining small amount of copper." On the one hand, this effectively reduces the etching time per cycle, thereby effectively preventing excessive erosion of the sidewalls of the circuit pattern and ensuring and improving the linewidth accuracy of the inner layer circuits. On the other hand, it reduces heat accumulation and drastic changes in chemical concentration during the etching process, ensuring the overall uniformity of the etching process and improving the quality of the inner layer circuits. ② Before performing the lamination layering operation, a resin layer with controllable thickness and good uniformity and consistency is filled in the gaps between the inner layer circuits using a composite printing process. This significantly reduces the filling difficulty during subsequent lamination layering operations, effectively avoiding voids caused by insufficient glue filling, thereby ensuring the quality of glue filling and interlayer bonding, and ensuring the overall structural stability of the PCB board. ③ The manufacturing method of the high-copper-thickness PCB board provided by this application is reasonable, has a simple process flow, and is easy to operate and implement. Attached Figure Description

[0017] Figure 1 This is a flowchart of the manufacturing method of the high-copper-thickness PCB board described in Embodiment 1 of the present invention; Figure 2 This is a schematic cross-sectional view of the substrate described in Example 1; Figure 3 This is a schematic cross-sectional view of the inner core board described in Example 1; Figure 4 This is a schematic cross-sectional view of the inner core board after the resin layer has been printed in Example 1. Figure 5 This is a schematic cross-sectional view of the inner layer circuit and the resin layer after leveling in Example 1; Figure 6 This is a schematic cross-sectional view of the intermediate plate described in Example 1; Figure 7 This is a schematic cross-sectional view of the structure after the outer layer circuitry is fabricated on the intermediate board in Example 1. Figure 8This is a schematic cross-sectional view of the high-copper-thickness PCB board obtained in Example 1.

[0018] Referring to the accompanying drawings, the following explanations are provided: 1. Substrate; 10. Insulating Intermediate Layer; 11. Base Copper Layer; 2. Inner Layer Circuitry; 3. Resin Layer; 4. Insulating Add-on Layer; 5. Add-on Copper Foil; 50. Carrier Copper Layer; 51. Ultra-thin Copper Layer; 6. Outer Layer Circuitry; 60. Connecting Copper Layer; 7. Solder Mask Layer; 8. Surface Treatment Layer; B1. Inner Core Board; B2. Intermediate Board; B3. High Copper Thick PCB Board. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Example 1

[0021] Please see the appendix Figure 1 To be continued Figure 8 As shown, this embodiment 1 provides a method for manufacturing a high-copper-weight PCB board, including the following manufacturing steps: S1: Provide a substrate 1, and use a subtractive method to fabricate an inner layer circuit 2 with a copper thickness of not less than 3 ounces on the substrate 1 to obtain an inner layer core board B1.

[0022] Specifically, the implementation structure of the substrate 1 is determined according to the design requirements of the PCB product, and this application does not impose any restrictions. However, in order to provide a clear and detailed description of the manufacturing method of the high-copper-thickness PCB provided in this application, this embodiment uses a double-sided copper-clad laminate as an example for explanation and illustration.

[0023] Please see the appendix Figure 2 As shown, the substrate 1 has the following structure: it has an insulating intermediate layer 10 and two base copper layers 11 respectively fixedly attached to opposite sides of the insulating intermediate layer 10. The insulating intermediate layer 10 may be, but is not limited to, a prepreg, and its thickness is determined according to product design requirements. The copper thickness of the base copper layer 11 is designed to be slightly greater than the copper thickness of the final inner layer circuit 2 to meet the processing requirements of leveling and other processes in subsequent manufacturing processes. It is understood that, according to the processing requirements of the high-copper-thickness PCB board described in this application, the copper thickness of the base copper layer 11 is greater than 3 ounces (in the field of circuit board technology, 1 ounce is approximately 35 μm).

[0024] Based on the above-described structure of the substrate 1, this embodiment employs a subtractive method for fabricating the inner layer circuitry. Specifically, the substrate 1 is sequentially subjected to cutting, baking, pre-coating treatment, coating with a photosensitive resist film, exposure, development, etching, and film removal to obtain an inner layer core board B1 with two inner layer circuits 2 (see attached diagram). Figure 3 As shown); where, ①The above-mentioned cutting and baking: refers to cutting the substrate 1 to a set size and then placing the substrate 1 in an oven to bake it, so as to eliminate the stress of the substrate 1 and ensure the dimensional / structural stability of the substrate 1 during the processing.

[0025] ②The above-mentioned pre-coating treatment and coating of photosensitive anti-corrosion film: refers to the process of roughening, cleaning and drying the surface of the substrate 1, and then coating the photosensitive anti-corrosion film onto the two copper base layers 11 by a vacuum laminating machine.

[0026] Furthermore, the substrate 1 can be roughened by browning or blackening processes to enhance the adhesion between the photosensitive dry film and the base copper layer 11.

[0027] ③The above-mentioned exposure and development: refers to exposing a portion of the resist photosensitive dry film according to the work data and using an LDI exposure machine, and then using a developer (commonly used developing solutions in the industry) to remove the unexposed areas of the resist photosensitive dry film.

[0028] ④ The above-mentioned etching and film removal: refers to using an etching solution to etch away the portions of the two substrate copper layers 11 that are exposed outside the resist photosensitive dry film, and then using a stripping solution (using a commonly used stripping solution in the industry) to remove the resist photosensitive dry film, thus obtaining the inner layer core board B1 with the inner layer circuit 2. As can be seen from the above, the copper thickness of the inner layer circuit 2 obtained at that time is greater than 3 ounces, and also slightly greater than the copper thickness setting value of its final product, in order to meet the processing requirements of the leveling process in the subsequent process.

[0029] Understandably, because the copper layer 11 of the base is relatively thick, if a one-time etching process is used during the etching process, the following defects are likely to occur: due to the long etching time, while the etching solution etches the copper layer in the vertical direction, it will also cause severe erosion of the sidewalls of the circuit pattern in the horizontal direction; thus, the line width of the circuit pattern becomes significantly smaller, resulting in unsatisfactory quality of the inner layer circuit.

[0030] To overcome the aforementioned deficiencies, this embodiment specifically improves and innovates the etching process by employing a two-stage etching process. In the two-stage etching process, the ratio between the etching amount in the first stage and the etching amount in the second stage is optimally controlled to be (1.1–2):1; this can also be understood as: the ratio between the thickness of copper removed in the first stage and the thickness of copper removed in the second stage is optimally controlled to be (1.1–2):1; furthermore, it is preferable that the ratio between the etching amount in the first stage and the etching amount in the second stage is optimally controlled to be (1.5–2):1. For example, when the copper thickness of the substrate copper layer 11 is designed to be 108 μm, the thickness of copper removed in the first stage can be designed to be approximately 72 μm or 68 μm, and correspondingly, the thickness of copper removed in the second stage is approximately 36 μm or 40 μm.

[0031] Understandably, this embodiment employs a two-stage etching process—first etching away most of the copper, then etching away the remaining small amount—essentially performing two stages of "thin copper" etching. This etching method effectively reduces the etching time per cycle, thereby preventing excessive erosion of the sidewalls of the circuit pattern and ensuring and improving the linewidth accuracy of the circuit pattern (i.e., the inner layer circuit 2). Furthermore, it reduces heat accumulation and drastic changes in solvent concentration during the etching process, ensuring overall uniformity of the etching process and thus improving the quality of the inner layer circuit 2. Additionally, the etching solution can be selectively replaced or replenished during the interval between the two etching stages, depending on actual production conditions, to ensure relatively stable solvent activity during both etching processes, further enhancing the overall uniformity of the etching process and improving the quality of the inner layer circuit 2.

[0032] Furthermore, in both etching processes described above, the raw material composition of the acidic etching solution is the same, as are the etching temperature and etching transfer speed. Specifically: in both etching processes, ① the concentration of sodium chlorate (NaClO3) in the acidic etching solution is 30–40 mol / L, the concentration of hydrochloric acid (HCl) is 2–2.5 mol / L, and the concentration of copper ions (Cu) is... 2+ The concentration is 130–150 g / L; understandably, hydrochloric acid (HCl) is used to provide chloride ions, form soluble complexes with copper ions to enhance etching ability, and also to maintain the acidity of the solution and prevent copper ions from hydrolyzing and forming precipitates; sodium chlorate (NaClO3) acts as an oxidant to oxidize monovalent copper ions generated during etching into divalent copper ions, thus achieving the recycling of copper ions. ② The etching temperature is 48℃–52℃, the etching conveying speed is 3–5 m / min, and the upper spray pressure is 1.5–3 Kgf / cm². 2 (further with 2.2 kgf / cm) 2 (Preferably) The spray pressure should be 1.5–2.5 kgf / cm². 2(further at 1.7 kgf / cm) 2 (Preferably).

[0033] Finally, after the inner core board B1 is manufactured, this embodiment also performs AOI optical inspection on the inner layer circuit 2 to ensure the quality of the inner layer circuit 2.

[0034] S2: First, the inner core board B1 is roughened, and then a resin layer 3 is printed on both sides of the inner core board B1 where the inner layer circuit 2 is located. The resin layer 3 protrudes slightly from the inner layer circuit 2. For details, please refer to the appendix. Figure 4 As shown.

[0035] Understandably, due to the thicker copper layer and deeper gaps G of the inner layer circuit 2, traditional lamination processes would inevitably result in defects such as insufficient filler and weak interlayer adhesion. To avoid these defects, this embodiment prints / fills the resin layer 3 into the gaps G of the inner layer circuit 2 before lamination, which significantly reduces the difficulty of filling the insulating layer 4 during subsequent lamination processes. This effectively avoids voids caused by insufficient filler, thereby ensuring filler quality and interlayer adhesion, and ultimately ensuring the stability of the overall PCB structure.

[0036] Furthermore, since the inner layer circuit 2 has a thicker copper layer and a deeper gap G between the lines, to ensure the printing / filling quality of the resin layer 3, this embodiment also specifically improves and innovates the printing process, adopting a composite printing process that combines one-time printing, pre-baking, two-time printing, and baking curing. Specifically, firstly, a negative screen is made corresponding to the inner layer circuit 2. Understandably, the opening area on the negative screen corresponds to the gap G area to be filled. The negative screen allows for precise printing of resin onto the gap G of the inner layer circuit 2, improving the printing quality. This improves the accuracy and quality of resin filling. Then, using a screen printing machine equipped with the negative screen, a first layer of resin of a set thickness is printed on the inner core board B1 and on both sides of the inner circuit 2. After the first layer of resin is pre-baked at a temperature of 115℃~125℃ for 10~15 minutes, a second layer of resin is printed on the inner core board B1 and on both sides of the inner circuit 2 using the screen printing machine. The two layers of resin are then baked until they are completely cured to obtain the resin layer 3.

[0037] Understandably, the aforementioned composite printing process can precisely fill the gaps between lines while also better controlling the total thickness of the resin layer 3. Compared to printing a thicker resin layer in one go, the layered printing adopted in this embodiment makes it easier to control the thickness of each resin layer, thus ensuring the uniformity and consistency of the resin layer 3 thickness and meeting the process requirements for resin layer thickness. In addition, this embodiment performs a pre-baking treatment after printing the first layer of resin, which allows the first layer of resin to initially cure and release some volatiles, reducing defects such as bubbles generated during the subsequent printing of the second layer of resin and the overall curing process. This improves the density of the resin layer and enables better bonding between the two layers of resin, enhancing the overall performance of the resin layer 3. Finally, the resin is baked and cured to ensure that the resin layer 3 achieves stable physical and chemical properties, and to facilitate subsequent handling and stacking.

[0038] Furthermore, in the aforementioned composite printing process, the thickness h of the first resin layer and the copper thickness H of the inner layer circuit 2 satisfy the following relationship: h = H × (30%–70%). For example, when the copper thickness H of the inner layer circuit 2 is designed to be approximately 108 μm, the thickness h of the first resin layer can be designed to be 35–70 μm, and more preferably 40–50 μm. Additionally, the baking and curing parameters are preferably: a baking temperature of 120°C and a baking time of 30–60 min.

[0039] Furthermore, to ensure better bonding between the resin layer 3 and the insulating reinforcement layer 4 in the subsequent process, this embodiment also specifically optimizes the material of the resin layer 3. Specifically, the glass transition temperature, coefficient of thermal expansion, and dielectric constant of the resin layer 3 and the insulating reinforcement layer 4 are the same or similar. Further, when the insulating reinforcement layer 4 uses a prepreg, the resin layer 3 uses a thermosetting resin, preferably any one of epoxy resin, polyimide resin, and BT resin, and even more preferably epoxy resin.

[0040] In addition, before printing, this embodiment also roughens the inner core board B1 through browning or blackening processes to enhance the bonding force between the inner core board B1 and the resin layer 3.

[0041] S3: During the above printing process, the resin layer 3 protrudes slightly beyond the inner layer circuit 2, and the resin layer 3 inevitably adheres to the outer surface of the inner layer circuit 2. To ensure the lamination quality in subsequent processes, this embodiment uses a ceramic grinding plate to level the inner layer circuit 2 and the resin layer 3. This ensures that the inner layer circuit 2 and the resin layer 3 are of equal thickness and flush, while also preventing the outer surface of the inner layer circuit 2 from being covered by the resin layer 3. (See attached document.) Figure 5As shown. Furthermore, it is understood that the grinding amount in the above-described ceramic grinding plate operation is a minute amount, a few micrometers.

[0042] In addition, for ease of description of subsequent processes, this embodiment will also define the board obtained after completing the S3 operation as board A.

[0043] S4: The insulating layer 4 and the copper foil layer 5 are stacked on both sides of the inner layer circuit 2 on the board A, and then laminated to obtain the intermediate board B2. (See attached document for details.) Figure 6 As shown.

[0044] In this embodiment, the insulating layer 4 is a prepreg, and the added copper foil 5 may be, but is not limited to, a "copper foil layer with a relatively thick copper thickness" or a "composite copper foil composed of a detachably connected carrier copper layer 50 and an ultra-thin copper layer 51". Furthermore, this embodiment illustrates the case where the added copper foil 5 is a composite copper foil.

[0045] Lamination is a common technique in the field of circuit board processing and is common knowledge, so it will not be described in detail here.

[0046] S5: Since this embodiment illustrates the case where the added copper foil 5 is made of composite copper foil, correspondingly, this embodiment uses mSAP process to fabricate the outer layer circuit.

[0047] Specifically, the above-mentioned mSAP process includes the following sequential processes performed on the intermediate board B2: baking (to relieve stress on the intermediate board B2), drilling (drilling alignment holes and vias on the intermediate board B2), board separation (mechanically peeling off the carrier copper layer 50), pre-coating treatment (including copper plating, cleaning, and drying), coating with photosensitive dry film (using a vacuum laminator), exposure, development, pattern electroplating (forming the outer layer circuit prototype and the connecting copper layer 60 between the outer layer circuit prototype and the inner layer circuit 2), film removal, and flash etching (removing the exposed ultra-thin copper layer 51); to obtain a semi-finished circuit board with the outer layer circuit 6 formed. For details, please refer to the appendix. Figure 7 As shown.

[0048] Understandably, ① in the obtained circuit board semi-finished product, the outer layer circuit 6 is electrically connected to the inner layer circuit 2 through the connecting copper layer 60. ② Since the mSAP process is a commonly used circuit fabrication method in circuit board processing, it will not be described in detail here. ③ After obtaining the outer layer circuit 6, this embodiment also performs AOI optical inspection on the outer layer circuit 6 to ensure the quality of the outer layer circuit 6.

[0049] Furthermore, if a thicker copper foil is used for the added copper foil 5 in actual operation, then a subtractive processing method will be used to fabricate the outer layer circuitry. The specific processing details of the subtractive processing method are described above and will not be repeated here.

[0050] S6: The obtained circuit board semi-finished product undergoes conventional processing steps including solder resist (forming solder resist layer 7), surface treatment (forming surface treatment layer 8, such as nickel-gold layer or nickel-palladium-gold layer), molding, electrical testing, finished product inspection, and packaging to obtain high-copper-thickness PCB board B3; see appendix for details. Figure 8 As shown.

[0051] As can be seen from the above, compared with the prior art, the high-copper-thickness PCB board manufacturing method provided in this embodiment 1 has the following advantages: ① This embodiment, through process innovation, adopts a two-stage etching process of "etching away most of the copper first, and then etching away the remaining small amount of copper". On the one hand, it can effectively reduce the etching time per etching, thereby effectively preventing the sidewalls of the circuit pattern from being excessively eroded, ensuring and improving the linewidth accuracy of the inner layer circuit 2; on the other hand, it can reduce the heat accumulation and drastic changes in chemical concentration during the etching process, ensuring the overall uniformity of the etching process and improving the quality of the inner layer circuit 2. ② Through process innovation, this embodiment also prints / fills a resin layer 3 with controllable thickness and good thickness uniformity and consistency in the line gap G of the inner layer circuit 2 using a composite printing process before performing the lamination layering operation. This significantly reduces the difficulty of filling the insulating layer 4 during the subsequent lamination layering operation, effectively avoiding voids caused by insufficient glue filling, thereby ensuring the glue filling quality and interlayer bonding force, and ensuring the overall structural stability of the PCB board. ③ The high-copper-thickness PCB board manufacturing method provided in this embodiment is reasonable, the process is simple, and it is easy to operate and implement.

[0052] Example 2

[0053] This embodiment 2 provides a high copper thickness PCB board, which is manufactured using the high copper thickness PCB board manufacturing method described in embodiment 1 above.

[0054] As can be seen from the above, the high-copper-thickness PCB board obtained in this embodiment 2 has the advantages of good overall structural stability, high thickness, high precision, and good quality of circuit patterns, which well meets the market demand for high-current and high-power electronic products.

[0055] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a high-copper-content thick PCB board, characterized in that: include: An inner layer circuit (2) with a copper thickness of not less than 3 ounces is fabricated on a substrate (1) using a subtractive method to obtain an inner layer core board; wherein, the etching process in the above subtractive method adopts a two-stage etching process, and the ratio between the etching amount of the first stage etching process and the etching amount of the second stage etching process is (1.1~2):

1. After roughening the inner core board, a resin layer (3) is printed on at least one side of the inner core board where the inner circuit (2) is located; wherein, the printing adopts a composite printing process that combines one printing, pre-baking, two printing and baking curing, and the resin layer (3) protrudes out of the inner circuit (2). The inner layer circuit (2) and the resin layer (3) are leveled so that the inner layer circuit (2) and the resin layer (3) are of equal thickness and flush, while the outer surface of the inner layer circuit (2) is not covered by the resin layer (3). The insulating layer (4) and the added copper foil (5) are stacked on the inner layer circuit (2) and laminated to obtain the intermediate board.

2. The method for manufacturing a high-copper-content thick PCB board according to claim 1, characterized in that: In the two etching processes mentioned above, the raw material composition of the acidic etching solution used is the same, as are the etching temperature and etching transfer speed. In addition, the ratio between the etching amount of the first etching process and the etching amount of the second etching process is (1.5~2):

1.

3. The method for manufacturing a high-copper-weight PCB board according to claim 2, characterized in that: The acidic etching solution contains sodium chlorate at a concentration of 30–40 mol / L, hydrochloric acid at a concentration of 2–2.5 mol / L, and copper ions at a concentration of 130–150 g / L. In the two etching processes described above, the etching temperature was 48℃~52℃, the etching conveyor speed was 3~5m / min, and the upper spray pressure was 1.5~3Kgf / cm. 2 The spray pressure is 1.5–2.5 kgf / cm². 2 .

4. The method for manufacturing a high-copper-weight PCB board according to claim 1, characterized in that: The glass transition temperature, coefficient of thermal expansion and dielectric constant of the resin layer (3) and the insulating layer (4) are the same or similar.

5. The method for manufacturing a high-copper-weight PCB board according to claim 4, characterized in that: The insulating layer (4) is a prepreg, and the resin layer (3) is any one of epoxy resin, polyimide resin and BT resin.

6. The method for manufacturing a high-copper-weight PCB board according to claim 1, characterized in that: The method for printing the resin layer (3) on at least one side of the inner core board where the inner layer circuit (2) is provided is as follows: Create a negative screen printing plate corresponding to the inner layer circuit (2); First, a first layer of resin of a set thickness is printed on at least one side of the inner core board with the inner layer line (2) using a screen printing machine equipped with the negative screen. Then, the first layer of resin is pre-baked at a temperature of 115°C to 125°C for 10 to 15 minutes. Next, a second layer of resin is printed on at least one side of the inner core board with the inner layer line (2) using the screen printing machine. Then, the two layers of resin are baked until they are completely cured to obtain the resin layer (3).

7. The method for manufacturing a high-copper-weight PCB board according to claim 6, characterized in that: The thickness h of the first resin layer and the copper thickness H of the inner layer circuit (2) satisfy the following relationship: h = H × (30% ~ 70%).

8. The method for manufacturing a high-copper-weight PCB board according to claim 1, characterized in that: The inner core board is roughened by browning or blackening process; the inner circuit (2) and the resin layer (3) are leveled by ceramic grinding plate method.

9. The method for manufacturing a high-copper-weight PCB board according to claim 1, characterized in that: Based on the characteristics of the added copper foil (5), the outer layer circuitry can be fabricated selectively using subtractive processing or mSAP process.

10. A high-copper-weight PCB board, characterized in that: It is manufactured using the manufacturing method of any one of claims 1-9 above.

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