Processing method of circuit board

Abstract

The invention discloses a processing method of a circuit board. The processing method comprises the following steps: laminating an insulating layer filled with anti-plating ink and a core board into a multi-layer board; the multilayer board is drilled to form blind holes, and anti-plating ink is arranged in the blind holes; ablating two ends of the blind hole to expose the copper foil at the bottom of the core plate layer; performing copper deposition processing on the blind hole to cover a first metal layer in the blind hole; washing off the anti-plating ink in the blind hole; and drilling the multilayer board to separate the first metal layer above the anti-plating ink removing position from the first metal layers on the two sides so as to form independent wiring. According to the invention, the blind hole is drilled in the multilayer board, then the whole board is subjected to the copper deposition process, the copper layer at the printing ink fading and washing position is removed by fading and washing the printing ink and using a drill bit with a small aperture, and the blind hole can be divided into four parts to form four independent wires, so that the inter-layer interconnection density is greatly increased, and the product meets the requirements of high-frequency and high-speed products.

Description

Technical Field

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

[0002] As the basis for all terminal products to exert their electronic performance, the PCB faces higher requirements in terms of design and processing. Especially with the current significant increase in the number of chip pins, there is a great challenge to the overall density of PCB traces. Research breakthroughs are being made to increase the wiring density within a limited space by changing the via hole diameter and using large-sized blind vias to disconnect and make designs with multiple outgoing lines.

[0003] In related technologies, for large-sized blind via disconnection, a long groove-shaped blind via needs to be fabricated first during processing. After blind via electroplating, a laser is used to ablate the electroplated copper, tin plating etching, and a large-diameter drill bit is used to drill off the copper in the middle disconnection part to make multiple outgoing lines. Among them, the laser solution is sometimes limited by the thickness of the PP, and there is a risk of insufficient ablation. The large-diameter hole drilling solution will squeeze the wiring space in the width direction, and the tin plating and tin stripping etching solution is also limited by the problem of laser processing ability.

[0004] However, the above solutions can only produce two independent lines at the same time. Although the design of large-sized blind via disconnection with multiple outgoing lines can indeed increase the wiring area, in the future scenario of increasing device high-density design, it is still necessary to pre-research a design that can additionally increase the outgoing lines, so as to make the performance of the next-generation products based on the PCB more excellent. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a processing method for a circuit board, which forms four independent traces, greatly increasing the density of interlayer interconnection, so that the product meets the requirements of high-frequency and high-speed products.

[0006] According to the processing method for a circuit board of an embodiment of the present invention, the processing method includes: laminating an insulating layer filled with anti-plating ink and a core board to form a multilayer board; drilling the multilayer board to form blind vias, and the anti-plating ink is provided in the blind vias; ablating both ends of the blind vias to expose the copper foil at the bottom of the core board layer; performing copper deposition processing on the blind vias to cover a first metal layer in the blind vias; washing and removing the anti-plating ink in the blind vias; performing drilling processing on the multilayer board to separate the first metal layer above the position where the anti-plating ink is removed from the first metal layers on both sides to form independent traces.

[0007] According to the processing method of the circuit board of an embodiment of the present invention, blind holes are drilled in the multilayer board, and then the entire board is subjected to a copper deposition process. The ink is then stripped and the copper layer at the ink-washed position is removed using a drill bit with a small aperture. The blind holes can be divided into four parts to form four independent traces, which greatly increases the density of inter-layer interconnection, so that the product meets the requirements of high-frequency and high-speed products.

[0008] According to some embodiments of the present invention, the processing method further includes: performing thickening electroplating on the multilayer board to thicken the first metal layer.

[0009] According to some embodiments of the present invention, the processing method further includes: filling the blind hole with resin.

[0010] According to some embodiments of the present invention, the processing method further includes: performing outer layer copper covering processing on the multilayer board to form a second metal layer on the outermost layer of the blind hole.

[0011] According to some embodiments of the present invention, the processing method further comprises: performing outer layer pattern processing on the multilayer board and performing solder mask protection.

[0012] According to some embodiments of the present invention, the processing method further includes: cutting grooves on the insulating layer and the core board layer, and filling the grooved areas with anti-plating ink.

[0013] According to some embodiments of the present invention, long slots are opened on the insulating layer and the core layer.

[0014] According to some embodiments of the present invention, the processing method further includes: when drilling the multilayer board, controlling the drilling depth of the resist ink area to retain at least a portion of the resist ink.

[0015] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which: Figure 1 Schematic diagram of a method for processing a circuit board according to an embodiment of the present invention Figure 1 ; Figure 2 Schematic diagram of a method for processing a circuit board according to an embodiment of the present invention Figure 2 ; Figure 3 Schematic diagram of a method for processing a circuit board according to an embodiment of the present invention Figure 3 ; Figure 4Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 4 ; Figure 5 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 5 ; Figure 6 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 6 ; Figure 7 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 7 ; Figure 8 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 8 ; Figure 9 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 9 ; Figure 10 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 10 ; Figure 11 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 11 One; Figure 12 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 12 Two; Figure 13 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 13 Three;[[ID=4...]] Figure 14 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 14 Four; Figure 15 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 15 Five; Figure 16 Schematic of the processing method of the circuit board according to an embodiment of the present invention Figure 16 Six.

[0017] Reference signs: 11. Insulation layer; 12. Core board layer; 13. Blind hole; 14. Anti-plating ink; 15. First metal layer; 16. Resin; 17. Second metal layer. Detailed implementation manners

[0018] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0019] Below, reference is made to Figures 1 - 16Describe the processing method of the circuit board according to the embodiments of the present invention.

[0020] Refer to Figures 3 - 11 As shown, in the processing method of the circuit board according to the embodiments of the present invention, the processing method includes: pressing the insulating layer 11 filled with anti-plating ink 14 and the core board layer 12 into a multilayer board. As Figure 3 shown, according to needs, multiple core boards are laminated with the insulating layer 11. Through the lamination method, signal lines, power lines, and ground lines can be arranged between different layers to form a good signal loop, and the rigidity and durability of the circuit board are improved. Among them, during the electroplating process, the anti-plating ink 14 can shield the areas that do not need to be plated, ensuring that only specific parts can be electroplated, thereby controlling the scope of electroplating or etching.

[0021] Drill the multilayer board to form blind vias 13, and anti-plating ink 14 is provided in the blind vias 13. As Figures 4 - 5 shown, the inside of the blind via 13 is treated with anti-plating ink 14, and in subsequent process treatments, this part is protected from being covered. Among them, the drilling method can be mechanical drilling.

[0022] Ablate both ends of the blind via 13 to expose the copper foil at the bottom of the core board layer 12. As Figure 6 shown, after drilling the multilayer board, the low end of the blind via 13 may be the base material of the insulating layer 11 or the core board layer 12. By ablating the medium around the blind via 13, the copper foil of the core board layer 12 is exposed for the next step of processing. Among them, ablating both ends of the blind via 13 can be carried out by laser drilling.

[0023] Perform copper deposition processing on the blind via 13 so that the first metal layer 15 covers the inside of the blind via 13. As Figure 7 shown, the hole walls formed by mechanical drilling or laser drilling are mainly composed of non-conductive materials. If electroplating is directly carried out, the current cannot pass through these hole walls, resulting in the inability to perform copper plating. Therefore, it is necessary to first form the first metal layer 15 on the hole walls of the blind via 13 through the copper deposition process, so as to achieve the attachment of electroplated copper.

[0024] Wash and remove the anti-plating ink 14 inside the blind via 13. As Figures 8 - 9 shown, the anti-toxic ink inside the blind via 13 is removed, and only the area where the anti-plating ink 14 was originally set does not form the first metal layer 15. That is to say, the first metal layer 15 in the blind via 13 is preliminarily segmented by the area where the anti-plating ink 14 is set. Among them, the method of washing and removing the anti-plating ink 14 can be chemical washing or physical washing.

[0025] Drill the multilayer board so that the first metal layer 15 above the position where the anti-plating ink 14 has been removed is separated from the first metal layers 15 on both sides to form independent traces. As Figures 10 - 11As shown, the drilling divides the first metal layer 15 on the peripheral wall of the blind via 13 and communicates with the position of the anti-plating ink 14 originally set at the bottom of the blind via 13. The isolated first metal layers 15 between two adjacent drillings can form independent traces. In this embodiment, small-sized drillings are performed on the multilayer board, and four holes are drilled on the peripheral wall of the blind via 13, so that four independent traces can be formed, greatly increasing the density of interlayer interconnection, thereby enabling the product to meet the requirements of high-frequency and high-speed products.

[0026] Thus, by drilling the blind via 13 in the multilayer board, then performing the full-board electroless copper plating process, and then removing the ink through stripping, the copper layer at the position of the removed ink is removed using a drill bit with a small-sized aperture. The blind via 13 can be divided into four parts to form four independent traces, greatly increasing the density of interlayer interconnection, thereby enabling the product to meet the requirements of high-frequency and high-speed products.

[0027] Refer to Figure 12 As shown, the processing method further includes: performing thickening electroplating on the multilayer board to thicken the first metal layer 15. Since no first metal layer 15 can be formed in the area where the anti-plating ink 14 was previously set, only the part where the first metal layer 15 was originally formed thickens after electroplating, which can further deepen the four lines, meet the interlayer interconnection requirements of the four parts, and greatly increase the flexibility of the interlayer interconnection density.

[0028] Refer to Figures 13 - 14 As shown, the processing method further includes: filling the blind via 13 with resin 16. That is, the multilayer board is subjected to vacuum resin 16 plugging of the holes, and the blind via 13 is filled with resin 16. After the resin 16 is filled, gas residues can be avoided, ensuring firm soldering, enhancing the structural strength of the holes, reducing the influence of thermal stress, improving the durability of the PCB, making the dielectric constant uniform, improving signal stability, and also enabling direct wiring of the upper-layer circuits, avoiding additional jumpers or bridges, and increasing the wiring density.

[0029] Refer to Figure 15 As shown, the processing method further includes: performing outer-layer copper covering processing on the multilayer board to form a second metal layer 17 on the outermost layer of the blind via 13. Specifically, chemical copper plating and electroplating thickening process treatments are performed on the outermost layer of the multilayer board to form the second metal layer 17, so that the second metal layer 17 covers the outermost layer of the blind via 13. In this way, subsequent graphic processing, etc. can be performed on the second metal layer 17, enhancing the electrical performance of the multilayer board, improving soldering reliability, optimizing signal integrity, increasing mechanical strength, and preventing chemical pollution and corrosion.

[0030] Refer to Figure 16As shown, the processing method also includes: processing the outer layer of the multilayer board and applying solder mask protection. Specifically, solder mask protection refers to the coating of a special solder mask layer during the printed circuit board manufacturing process to prevent unnecessary solder from flowing to places where it should not be soldered during the soldering process. The solder mask protector covers the exposed copper circuits, preventing solder from splashing to places where it should not be soldered during soldering, preventing short circuits and incorrect soldering, and effectively protecting the circuits from direct exposure to air to prevent oxidation and corrosion.

[0031] Reference Figures 1 - 2 As shown, the processing method further includes: slotting the insulating layer 11 and the core plate layer 12, and filling the slotted area with plating resist ink 14. Wherein, long slots can be opened on the insulating layer 11 and the core plate layer 12.

[0032] In addition, the processing method also includes: when drilling a multilayer board, controlling the drilling depth of the anti-plating ink 14 area to retain at least part of the anti-plating ink 14, at least part of the anti-plating ink 14 can control the gaps between the first metal layers 15 in different areas, so as to facilitate subsequent small-size drilling to ensure that separate traces can be formed.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0035] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A processing method for a circuit board, characterized in that, The processing method includes: Laminating an insulating layer filled with anti-plating ink and a core board to form a multilayer board; Drilling the multilayer board to form blind vias, with the anti-plating ink provided in the blind vias; Ablating both ends of the blind vias to expose the copper foil at the bottom of the core board layer; Performing copper deposition processing on the blind vias to cover a first metal layer in the blind vias; Washing and removing the anti-plating ink in the blind vias; Drilling the multilayer board to separate the first metal layer above the position where the anti-plating ink is removed from the first metal layers on both sides to form independent traces.

2. The processing method of the circuit board according to claim 1, wherein The processing method further includes: Performing thickening electroplating on the multilayer board to thicken the first metal layer.

3. The processing method of the circuit board according to claim 2, characterized in that, The processing method further includes: Filling the blind vias with resin.

4. The processing method of the circuit board according to claim 3, wherein, The processing method further includes: Performing outer layer copper covering processing on the multilayer board to form a second metal layer on the outermost layer of the blind vias.

5. The processing method of the circuit board according to claim 4, characterized in that, The processing method further includes: Performing outer layer pattern processing on the multilayer board and performing solder mask protection.

6. The processing method of the circuit board according to claim 1, wherein The processing method further includes: Grooving the insulating layer and the core board layer and filling anti-plating ink in the grooved area.

7. The processing method of the circuit board according to claim 6, characterized in that, Opening long slot holes in the insulating layer and the core board layer.

8. The processing method of the circuit board according to claim 1, characterized in that, The processing method further includes: When drilling the multilayer board, controlling the drilling depth of the anti-plating ink area to retain at least part of the anti-plating ink.

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