A manufacturing method of a circuit board with metallized vias in blind vias

Abstract

The present invention discloses a method for manufacturing a circuit board containing a metallized through-hole in a blind groove, comprising the following steps: step S1, providing an inner substrate, machining a metallized through-hole on the inner substrate, machining a groove circuit on the upper end surface of the inner substrate, and plating a gold layer on the hole wall of the metallized through-hole; step S2, covering the upper end opening of the metallized through-hole on the inner substrate with a sealing material, and affixing a resist material on the upper end surface of the sealing material; step S3, providing a prepreg, and forming a clearance groove on the prepreg; step S4, providing an outer substrate, stacking the inner substrate, the prepreg, and the outer substrate in sequence from bottom to top and pressing them into a circuit board; step S5, manufacturing an outer circuit on the outer surface of the circuit board; step S6, forming a blind groove on the outer substrate, and exposing the resist material in the blind groove; step S7, removing the resist material and the sealing material in the blind groove, so that the groove circuit is exposed at the bottom surface of the blind groove, and the metallized through-hole is connected to the blind groove.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit boards, and in particular to a method for manufacturing a circuit board containing metallized through holes in blind slots. Background Art

[0002] Blind slots are a common structure in printed circuit boards (PCBs), primarily used for mounting components or securing products, improving overall product integration and achieving signal shielding. In some product structures, the sidewalls of the blind slot are non-metallized, while the bottom wall is required to form the in-slot circuitry. This bottom wall also features plated-through holes (PTHs). Accurately producing high-quality in-slot circuitry in this product structure has become a significant challenge within the industry. If the blind slot is machined after lamination and then the in-slot circuitry is etched, etching within the blind slot is restricted by the sidewall structure and the lack of metallization. This not only makes etching difficult but can also result in incomplete etching and inaccurate etching due to residual chemical residue. This can lead to copper thickness requirements not being met, impacting PCB production quality. If the in-slot circuitry is etched at this location before lamination, chemical residue can easily seep into the in-slot circuitry through the PTHs during the subsequent formation of the outer layers of a double-sided or multi-layer board, causing corrosion damage to the circuitry. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, the present invention aims to provide a method for manufacturing a circuit board having a metallized through hole in a blind slot, which can facilitate the processing of the circuit in the slot and protect the circuit in the slot in subsequent processing steps.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is as follows: A method for manufacturing a circuit board containing a metallized through-hole in a blind groove, comprising the following steps: Step S1, providing an inner substrate, processing a metallized through-hole on the inner substrate, processing a circuit in the groove on the upper end surface of the inner substrate, and plating a gold layer on the hole wall of the metallized through-hole; Step S2, using a sealing material to cover the upper end opening of the metallized through-hole on the inner substrate, and applying a resist material to the upper end surface of the sealing material, wherein the resist material completely covers the circuit in the groove; Step S 3. Provide a prepreg and open a clearance groove on the prepreg; step S4, provide an outer substrate, stack the inner substrate, prepreg and outer substrate in sequence from bottom to top and press them into a circuit board, wherein the adhesive resist material is located in the clearance groove; step S5, make an outer layer circuit on the outer surface of the circuit board; step S6, open a blind groove on the outer substrate and expose the adhesive resist material in the blind groove; step S7, remove the adhesive resist material and sealing material in the blind groove so that the circuit in the groove is exposed on the bottom surface of the blind groove, and connect the metallized through hole with the blind groove.

[0005] Compared with the existing technology, the above technical solution has at least the following beneficial effects: the method first processes the in-groove circuit on the inner substrate, which reduces the difficulty of making the in-groove circuit, and can make circuits with smaller line widths and spacings. After the in-groove circuit is processed, the in-groove circuit is protected by a resist material. The resist material can prevent the cured glue formed by the semi-cured sheet during the pressing process from flowing into the in-groove circuit. When the outer layer circuit is subsequently made, since the blind groove has not yet been opened, it is possible to avoid the in-groove circuit being damaged by the flow of the liquid medicine from the blind groove. The upper end opening of the metallized through hole is covered by the sealing material. When the liquid medicine flows into the metallized through hole, it cannot penetrate into the in-groove circuit from the upper end opening of the metallized through hole. The hole wall of the metallized through hole is protected by the gold layer. When the liquid medicine flows into the metallized through hole, it will not etch the in-groove circuit from the upper end hole wall of the metallized through hole. The in-groove circuit in the blind groove can be further protected, solving the problem of the in-groove circuit being damaged during the production process.

[0006] The above-mentioned method for manufacturing a circuit board containing a metallized through-hole in a blind groove, step S5 includes the following steps: S51, copper-cladding the circuit board to cover the outer surface of the circuit board and the hole wall of the metallized through-hole with a first copper layer; S52, affixing a first dry film on the first copper layer on the outer surface of the circuit board, and performing external light imaging on the circuit board to obtain the desired outer layer circuit pattern, and the first dry film on the outer layer circuit pattern is still retained; S53, tin-plating the circuit board to cover the position of the first copper layer where the first dry film is not retained with a tin layer, while the position where the first dry film is affixed is not covered with a tin layer; S54, affixing a second dry film on the outer surface of the tin layer, and removing the tin layer at the hole wall of the metallized through-hole; S55, removing the second dry film and the first dry film, and etching the circuit board to etch away the first copper layer where the tin layer is not covered to obtain the desired outer layer circuit; S56, removing the tin layer on the outer surface of the first copper layer.

[0007] The above-mentioned method for manufacturing a circuit board containing a metallized through hole in a blind slot further includes the following step before step S51: machining an integral through hole on the circuit board.

[0008] In the above-mentioned method for manufacturing a circuit board containing a metallized through-hole in a blind groove, in step S51, the hole wall of the integral through-hole is also covered with a first copper layer to obtain an integral metallized through-hole; in step S53, the hole wall of the integral metallized through-hole is also covered with a tin layer; in step S54, a second dry film covers the two end openings of the integral metallized through-hole; in step S56, the tin layer on the hole wall of the integral metallized through-hole is also removed.

[0009] The above-mentioned method for manufacturing a circuit board containing a metallized through-hole in a blind groove, step S1 includes the following steps: S11, providing an inner substrate, and drilling an inner through-hole on the inner substrate; S12, copper-cladding the inner substrate to coat the surface of the inner substrate and the hole wall of the inner through-hole with a second copper layer to obtain a metallized through-hole; S13, making a circuit in the groove; S14, plating a gold layer on the hole wall of the metallized through-hole.

[0010] In the above-mentioned method for manufacturing a circuit board having a metallized through hole in a blind slot, in step S2, the thickness of the sealing material applied is 0.03 mm to 0.04 mm.

[0011] In the above-mentioned method for manufacturing a circuit board containing a metallized through hole in a blind groove, the thickness of the resist material is equal to the thickness of the prepreg.

[0012] In the above-mentioned method for manufacturing a circuit board containing metallized through holes in blind grooves, the adhesive resist material and the sealing material are both polyimide.

[0013] In the above-mentioned method for manufacturing a circuit board containing a metallized through hole in a blind slot, the viscosity of the sealing material is stronger than that of the adhesive blocking material.

[0014] In the above-mentioned method for manufacturing a circuit board having a metallized through hole in a blind groove, after step S5, the circuit board is cleaned to remove residual chemicals.

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a process flow chart of a manufacturing method according to an embodiment of the present invention;

[0017] Figure 2a Schematic diagram of the processing of step S11 in the manufacturing method according to an embodiment of the present invention;

[0018] Figure 2b Schematic diagram of the processing of step S12 in the manufacturing method according to an embodiment of the present invention;

[0019] Figure 2c Schematic diagram of the processing of step S13 in the manufacturing method according to an embodiment of the present invention;

[0020] Figure 2d Schematic diagram of the processing of step S14 in the manufacturing method according to an embodiment of the present invention;

[0021] Figure 3 and Figure 4 Schematic diagram of the processing of step S2 in the manufacturing method according to an embodiment of the present invention;

[0022] Figure 5Schematic diagram of processing of step S3 and step S4 in the manufacturing method of an embodiment of the present invention;

[0023] Figure 6 Schematic diagram of the processing of step S4 in the manufacturing method according to an embodiment of the present invention;

[0024] Figure 7 Schematic diagram of the processing of step S51 in the manufacturing method according to an embodiment of the present invention;

[0025] Figure 8 Schematic diagram of the processing of step S52 in the manufacturing method according to an embodiment of the present invention;

[0026] Figure 9 Schematic diagram of the processing of step S53 in the manufacturing method according to an embodiment of the present invention;

[0027] Figure 10 Schematic diagram of the processing of step S54 in the manufacturing method according to an embodiment of the present invention;

[0028] Figure 11 and Figure 12 Schematic diagram of the processing of step S55 in the manufacturing method according to an embodiment of the present invention;

[0029] Figure 13 Schematic diagram of the processing of step S56 in the manufacturing method according to an embodiment of the present invention;

[0030] Figure 14 Schematic diagram of the processing of step S6 in the manufacturing method according to an embodiment of the present invention;

[0031] Figure 15 Schematic diagram of the processing of step S7 in the manufacturing method according to an embodiment of the present invention;

[0032] Figure 16 It is a schematic diagram of the structure after the integral metallized through hole is processed in the manufacturing method of an embodiment of the present invention.

[0033] Description of Figure Numbers:

[0034] Inner substrate 100, circuit in slot 110, metallized through hole 120, gold layer 121, inner through hole 122, outer substrate 200, blind slot 210,

[0035] Prepreg 300, clearance groove 310,

[0036] Glue blocking material 400;

[0037] Sealing material 500;

[0038] Outer circuit 600;

[0039] a first copper layer 710, tin layers 720 and 730, a second copper layer;

[0040] A first dry film 810 and a second dry film 820;

[0041] The entire through hole 900 is metallized. DETAILED DESCRIPTION

[0042] The embodiments of the present invention are described in detail below. Figures 1 to 15 An embodiment of the present invention provides a method for manufacturing a circuit board having a metallized through hole in a blind slot 210, comprising the following steps:

[0043] Step S1: providing an inner substrate 100, processing a metallized through hole 120 on the inner substrate 100, processing an in-slot circuit 110 on the upper end surface of the inner substrate 100, and plating a gold layer 121 on the hole wall of the metallized through hole 120;

[0044] Step S2: Figure 3 As shown, a sealing material 500 is used to cover the upper end opening of the metallized through hole 120 on the inner substrate 100, as shown in FIG. Figure 4 As shown, a resist material 400 is attached to the upper end surface of the sealing material 500 , wherein the resist material 400 completely covers the circuit 110 in the slot;

[0045] Step S3, as Figure 5 As shown, a prepreg 300 is provided, and a clearance groove 310 is opened on the prepreg 300;

[0046] Step S4: Figure 5 As shown, an outer substrate 200 is provided, and the inner substrate 100, the prepreg 300, and the outer substrate 200 are stacked and pressed together from bottom to top to form a circuit board, wherein the adhesive resist material 400 is located in the recess 310; in some embodiments, the outer substrate 200 provided is a substrate that has been pre-copper-clad;

[0047] Step S5: Figures 6 to 13 As shown, an outer layer circuit 600 is made on the outer surface of the circuit board;

[0048] Step S6: Figure 14 As shown, a blind groove 210 is opened on the outer substrate 200, and the resist material 400 is exposed in the blind groove 210;

[0049] Step S7: Figure 15 As shown, the resist material 400 and the sealing material 500 in the blind trench 210 are removed, so that the circuit 110 in the trench is exposed at the bottom surface of the blind trench 210 , and the metallized through hole 120 is connected to the blind trench 210 .

[0050] In step S1 of this method, the in-slot circuit 110 is first processed on the inner substrate 100. Compared with processing the in-slot circuit 110 after the blind groove 210 is formed, processing the in-slot circuit 110 directly on the board surface can reduce the difficulty of manufacturing the in-slot circuit 110, can produce circuits with smaller line widths and spacings, and can produce the in-slot circuit 110 more accurately. In step S2, after the in-slot circuit 110 is processed, the in-slot circuit 110 is protected by a glue blocking material 400. The glue blocking material 400 can prevent the cured glue formed by the semi-cured sheet 300 during the pressing process from flowing into the in-slot circuit 110. When the outer layer circuit 600 is subsequently manufactured, since the blind groove 210 has not yet been opened, it can be prevented from damaging the in-slot circuit 110 due to the flow of chemicals from the blind groove 210. The upper opening of the plated through-hole 120 is covered by the sealing material 500. When the chemical enters the plated through-hole 120, it cannot penetrate into the in-slot circuit 110 from the upper opening of the plated through-hole 120. Furthermore, the hole wall of the plated through-hole 120 is protected by the gold layer 121. When the chemical enters the plated through-hole 120, it cannot etch the in-slot circuit 110 from the upper hole wall of the plated through-hole 120. This further protects the in-slot circuit 110 in the blind trench 210 and solves the problem of in-slot circuit 110 being damaged during the production process.

[0051] Specifically, if Figure 2a 、 2b , 2c and 2d, in some embodiments, step S1 includes the following steps:

[0052] S11, providing an inner substrate 100, and drilling an inner through hole 122 on the inner substrate 100;

[0053] S12, performing copper cladding on the inner substrate 100 to coat the surface of the inner substrate 100 and the wall of the inner through hole 122 with a second copper layer 730, thereby increasing the copper thickness on the surface of the inner substrate 100 and obtaining the metallized through hole 120;

[0054] S13, manufacturing the in-slot circuit 110, during the manufacturing process, forming the required in-slot circuit 110 through a coating-photosensitive-etching process;

[0055] S14 , plating a gold layer 121 on the hole wall of the metallized through hole 120 .

[0056] In step S1, the inner substrate 100 is made into the in-slot circuit 110 and the required metallized through-hole 120 before lamination, which is conducive to the accurate depiction of the in-slot circuit 110 on the inner substrate 100, prevents the occurrence of inaccurate etching patterns, and can improve the production accuracy and quality of the circuit board. In addition, a gold layer 121 is plated on the hole wall of the metallized through-hole 120, and then used in conjunction with the sealing material 500. Whether it is the upper end hole or the side wall of the metallized through-hole 120, the chemical cannot penetrate and corrode, thereby fully protecting the in-slot circuit 110. Specifically, in step S2, the thickness of the sealing material 500 applied is 0.03mm to 0.04mm, which can not only ensure sufficient ability to prevent the infiltration of chemical liquid, but also avoid the influence of the sealing material 500 being too thick on the coating of the adhesive resistance material 400. After applying the sealing material 500 , the adhesive resist material 400 is directly applied on the upper surface of the sealing material 500 and then the prepreg 300 is pressed. This ensures that the adhesive resist material 400 is accurately applied and that the adhesive resist material 400 completely covers the circuit 110 in the slot, thereby ensuring the protection effect of the circuit 110 in the slot.

[0057] Specifically, the thickness of the adhesive resist material 400 is equal to or slightly less than that of the prepreg 300. After the inner substrate 100 and the outer substrate 200 are laminated together, the thickness of the prepreg 300 decreases, allowing the adhesive resist material 400 to just block the outside of the circuits 110 in the slot. It also provides space for the sealing material 500 before lamination, preventing the sealing material 500 from pushing out of the prepreg 300. Specifically, both the adhesive resist material 400 and the sealing material 500 are made of polyimide, which offers high temperature resistance, high strength, and corrosion resistance, effectively preventing chemical infiltration. Specifically, the sealing material 500 has a stronger viscosity than the adhesive resist material 400. After the adhesive resist material 400 is applied, the adhesive resist material 400 may be deformed during lamination. At this time, the adhesive resist material 400 may slide relative to the sealing material 500, but will not cause the sealing material 500 to slide, thereby preventing the sealing material 500 from being unable to completely cover the upper end of the metallized through-hole 120 due to the sliding of the sealing material 500.

[0058] Specifically, refer to Figures 6 to 13 In some embodiments, step S5 includes the following steps:

[0059] S51, performing copper cladding processing on the circuit board to coat the outer surface of the circuit board and the hole wall of the metallized through hole 120 with a first copper layer 710;

[0060] S52, affixing a first dry film 810 on the first copper layer 710 on the outer surface of the circuit board, and performing external light imaging processing on the circuit board to obtain a desired outer layer circuit pattern, with the first dry film 810 on the outer layer circuit pattern still retained;

[0061] S53, tinning the circuit board so that the positions of the first copper layer 710 where the first dry film 810 is not retained are covered with the tin layer 720, while the positions where the first dry film 810 is attached are not covered with the tin layer 720;

[0062] S54, applying a second dry film 820 on the outer surface of the tin layer 720, and removing the tin layer 720 at the hole wall of the metallized through hole 120;

[0063] S55, removing the second dry film 820 and the first dry film 810, and etching the circuit board to etch away the first copper layer 710 where the tin layer 720 is not covered, to obtain the desired outer layer circuit 600;

[0064] S56 , removing the tin layer 720 on the outer surface of the first copper layer 710 .

[0065] Specifically, in step S51, the copper cladding process can be performed using a copper plating process. In order to ensure the flatness of the copper plating on the board surface and facilitate the subsequent production of the outer layer circuit 600, the openings of the metallized through-holes 120 are not blocked (if the openings are blocked by a film, the openings will not be plated with a copper layer, and the copper thickness will be less than that at other locations, which will cause an uneven board surface). Therefore, in step S51, the hole walls of the metallized through-holes 120 are also plated with a first copper layer 710. Thereafter, in step S52, a first dry film 810 is applied to the first copper layer 710 on the outer surface of the circuit board. After the external light imaging process, the first dry film 810 on the outer layer circuit pattern is retained, while the first dry film 810 at other locations is removed during the external light imaging process. In step S53, to protect the copper layer in areas not covered with the first dry film 810 from being removed during the subsequent etching process, the circuit board is tinned to coat the areas of the first copper layer 710 where the first dry film 810 is not retained with a tin layer 720. Similarly, in this step, to completely coat the areas not covered with the first dry film 810 with the tin layer 720, the lower opening of the plated through hole 120 is not blocked, resulting in the tin layer 720 coating the first copper layer 710 on the wall of the plated through hole 120.

[0066] Since the hole wall of the plated through hole 120 is covered with the tin layer 720 in step S3 in step S54, the tin layer 720 will cover the first copper layer 710, making it impossible to remove the first copper layer 710 in the plated through hole 120 during subsequent etching (which will cause the hole diameter of the plated through hole 120 to not meet the requirements). Therefore, it is necessary to first remove the tin layer 720 in the plated through hole 120. In step S54, after the tin layer 720 on the outer surface of the circuit board is applied with the second dry film 820, the tin layer 720 is etched and stripped. This can both protect the tin layer 720 on the outer surface of the circuit board and remove the tin layer 720 in the plated through hole 120. In step S55, after removing the second dry film 820 and the first dry film 810, the copper material at the outer layer circuit pattern is exposed, while other locations are protected by the tin layer 720. The first copper layer 710 within the metallized through-hole 120 is also exposed. In this step, alkaline etching can be performed to etch away the copper material at the outer layer circuit pattern and the first copper layer 710 within the metallized through-hole 120, thereby obtaining the desired outer layer circuit 600 and ensuring that the aperture of the metallized through-hole 120 meets the requirements. After obtaining the outer layer circuit 600, in step S56, alkaline etching is performed to remove the tin layer 720 on the outer surface of the first copper layer 710, ultimately obtaining the desired circuit board structure. Specifically, after step S5, the circuit board is cleaned to remove residual chemicals to prevent damage to the circuit 110 within the slot due to residual chemicals when the blind slot 210 is opened. Specifically, the blind slot 210 can be opened by milling, which can accurately process the blind slot 210.

[0067] Specifically, in some embodiments, another hole structure can be made on the circuit board, which can be a metalized hole or a non-metalized hole. Figure 16 As shown, an embodiment of manufacturing an integral metallized through-hole 900 is provided herein. Before step S51, an integral through-hole is first processed on the circuit board. In step S51, when the circuit board is subjected to a copper cladding process, the hole wall of the integral through-hole is also covered with a first copper layer 710 to obtain the integral metallized through-hole 900; in step S53, the hole wall of the integral metallized through-hole 900 is also covered with a tin layer 720; in step S54, a second dry film 820 covers the two end openings of the integral metallized through-hole 900; in step S56, the tin layer 720 on the hole wall of the integral metallized through-hole 900 is also removed.

[0068] It should be noted that in the description of the present invention, if there are any descriptions of directions, such as up, down, front, back, left, right, etc., the directions or positional relationships indicated are all based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed or operate in a specific direction, and cannot be understood as a limitation on the present invention.

[0069] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. If there are descriptions of "first," "second," and so on, these are used solely to distinguish technical features and are not to be construed as indicating or implying relative importance, or implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0070] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0071] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A method for manufacturing a circuit board having a metallized through hole in a blind slot, characterized in that: The steps include: Step S1, providing an inner substrate (100), processing a metallized through hole (120) on the inner substrate (100), processing an in-slot circuit (110) on the upper end surface of the inner substrate (100), and plating a gold layer (121) on the hole wall of the metallized through hole (120); Step S2: using a sealing material (500) to cover the upper end opening of the metallized through hole (120) on the inner substrate (100), and applying a resist material (400) to the upper end surface of the sealing material (500), wherein the resist material (400) completely covers the circuit (110) in the groove; Step S3, providing a prepreg (300), and forming a clearance groove (310) on the prepreg (300); Step S4: providing an outer substrate (200), and stacking the inner substrate (100), the prepreg (300), and the outer substrate (200) in sequence from bottom to top and pressing them into a circuit board, wherein the adhesive resist material (400) is located in the clearance groove (310); Step S5, making an outer layer circuit (600) on the outer surface of the circuit board; Step S6: opening a blind groove (210) on the outer substrate (200), and exposing the adhesive resist material (400) in the blind groove (210); Step S7: removing the resist material (400) and the sealing material (500) in the blind groove (210) so that the circuit (110) in the groove is exposed on the bottom surface of the blind groove (210) and the metallized through hole (120) is connected to the blind groove (210).

2. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 1, wherein: The step S5 comprises the following steps: S51, performing copper coating on the circuit board to coat the outer surface of the circuit board and the hole wall of the metallized through hole (120) with a first copper layer (710); S52, affixing a first dry film (810) on the first copper layer (710) on the outer surface of the circuit board, and performing external light imaging processing on the circuit board to obtain a desired outer layer circuit pattern, with the first dry film (810) on the outer layer circuit pattern still remaining; S53, tinning the circuit board, so that the positions of the first copper layer (710) where the first dry film (810) is not retained are covered with a tin layer (720), while the positions where the first dry film (810) is retained are not covered with the tin layer (720); S54, applying a second dry film (820) to the outer surface of the tin layer (720), and removing the tin layer (720) at the hole wall of the metallized through hole (120); S55, removing the second dry film (820) and the first dry film (810), and etching the circuit board to etch away the first copper layer (710) not covered with the tin layer (720), to obtain the required outer layer circuit (600); S56, removing the tin layer (720) on the outer surface of the first copper layer (710).

3. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 2, wherein: Before step S51 , the method further includes the following steps: machining an integral through hole on the circuit board.

4. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 3, wherein: In step S51, the hole wall of the integral through hole is also covered with the first copper layer (710) to obtain the integral metallized through hole (900); in step S53, the hole wall of the integral metallized through hole (900) is also covered with the tin layer (720); in step S54, the second dry film (820) covers the two end openings of the integral metallized through hole (900); in step S56, the tin layer (720) on the hole wall of the integral metallized through hole (900) is also removed.

5. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 1, wherein: The step S1 comprises the following steps: S11, providing an inner substrate (100), and drilling an inner through hole (122) on the inner substrate (100); S12, performing copper coating treatment on the inner substrate (100) to coat the surface of the inner substrate (100) and the hole wall of the inner through hole (122) with a second copper layer (730), thereby obtaining a metallized through hole (120); S13, making a circuit in the slot (110); S14, plating a gold layer (121) on the hole wall of the metallized through hole (120).

6. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 1, wherein: In the step S2, the thickness of the sealing material (500) applied is 0.03 mm to 0.04 mm.

7. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 1, wherein: The thickness of the adhesive resist material (400) is equal to the thickness of the prepreg (300).

8. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 1, wherein: The adhesive blocking material (400) and the sealing material (500) are both polyimide.

9. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 1, wherein: The sealing material (500) has a stronger viscosity than the adhesive blocking material (400).

10. The method for manufacturing a circuit board having a metallized through hole in a blind slot according to claim 1, wherein: After step S5, the circuit board is cleaned to remove residual chemicals.

Images