Manufacturing method of mechanical blind hole, manufacturing method of PCB and PCB

Abstract

The invention provides a manufacturing method of a mechanical blind hole, a manufacturing method of a PCB and the PCB, and relates to the technical field of PCB manufacturing, the manufacturing method of the mechanical blind hole comprises the following steps that a first hole is machined in the position, corresponding to a target blind hole, of a first sub-board, and the size of the first hole is larger than that of the target blind hole; processing a conductive layer in the first hole, wherein the inner diameter of the conductive layer is smaller than the aperture of the target blind hole; filling the first hole with a filling material; the first daughter board and the second daughter board are combined to form a composite structure; and a target blind hole is machined in the composite structure. The first hole is prefabricated, the conductive layer is processed in the first hole, the first hole is filled and then combined with the second sub-board, and then the target blind hole is processed, so that the problems of no copper at the hole bottom and rough hole wall of the blind hole in the prior art are solved. According to the manufactured PCB, the open circuit risk caused by the fact that no copper exists at the bottom of the blind hole can be effectively avoided, and the quality and reliability of the PCB are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB manufacturing, and in particular to a method for manufacturing a mechanical blind hole, a method for manufacturing a PCB board, and a PCB board. Background Art

[0002] In printed circuit board (PCB) manufacturing, mechanical blind vias are key structures that connect circuits on different layers. As the demand for high density, high performance and miniaturization of electronic devices continues to grow, mechanical blind vias on PCB boards are also moving towards high aspect ratios.

[0003] The aspect ratio, which is the ratio of the blind hole depth to the hole diameter, is an important indicator to measure the difficulty of blind hole processing. When the aspect ratio exceeds a certain value (for example, 0.8:1), it is difficult for traditional mechanical drilling and electroplating processes to form a uniform and reliable conductive layer at the bottom of the blind hole, and defects such as no copper at the bottom of the hole and open circuits are prone to occur, which seriously affects the performance and reliability of the PCB. Especially in high-speed and high-frequency circuits, these defects will lead to a decrease in the integrity of signal transmission and affect the normal operation of the circuit.

[0004] Therefore, it is necessary to improve the existing technology for making mechanical blind holes to overcome the defects of the existing technology. Summary of the invention

[0005] In order to overcome the problems existing in the related art, one of the purposes of the present invention is to provide a method for making a mechanical blind hole. The method for making a mechanical blind hole prefabricates a first hole, processes a conductive layer in the first hole, fills the first hole and combines it with a second sub-board, and then processes a target blind hole to overcome the problem of blind holes in the prior art that there is no copper at the bottom of the hole and the hole wall is rough.

[0006] A method for making a mechanical blind hole, comprising:

[0007] Processing a first hole at a position corresponding to the target blind hole on the first sub-plate, wherein the size of the first hole is larger than the size of the target blind hole;

[0008] Processing a conductive layer in the first hole, wherein the inner diameter of the conductive layer is smaller than the diameter of the target blind hole;

[0009] filling the first hole with a filling material;

[0010] combining the first sub-panel and the second sub-panel to form a composite structure;

[0011] The target blind hole is machined on the composite structure.

[0012] By pre-processing a first hole larger than the target blind hole size on the first sub-board, forming a conductive layer therein, filling it and combining it with the second sub-board, and finally processing the target blind hole on the composite structure, it is easier to control the size and shape of the hole when subsequently processing the target blind hole on the composite structure, avoiding the difficulty of directly processing the conductive layer in the high aspect ratio blind hole, thereby improving the production efficiency and yield of the mechanical blind hole.

[0013] Furthermore, processing the target blind hole on the composite structure includes:

[0014] Controlled-depth drilling is performed on the composite structure at a position corresponding to the first hole to expose the conductive layer and form the target blind hole.

[0015] The target blind hole is processed by controlled depth drilling, which can accurately control the drilling depth to ensure that the conductive layer is exposed, while avoiding excessive drilling to damage other structures, thereby ensuring the electrical connection performance and structural stability of the target blind hole.

[0016] Furthermore, the target blind via is a high aspect ratio mechanical blind via.

[0017] It specifically solves the difficult problems in the production of high aspect ratio mechanical blind vias, such as no copper at the bottom of the hole and rough hole walls, and improves the quality and reliability of high aspect ratio mechanical blind vias.

[0018] Furthermore, the material of the conductive layer is metal.

[0019] Furthermore, the material of the conductive layer is copper.

[0020] Furthermore, the conductive layer is formed by electroplating.

[0021] Furthermore, the filling material is resin.

[0022] Furthermore, the thickness of the first sub-plate is greater than or equal to the depth of the target blind hole.

[0023] A second object of the present invention is to provide a method for manufacturing a PCB board, including the method for manufacturing the mechanical blind via as described above.

[0024] By using the method for manufacturing mechanical blind vias as described above, the method for manufacturing a PCB board can manufacture a PCB board with higher quality mechanical blind vias, thereby improving the manufacturing efficiency and product quality of the PCB board.

[0025] Furthermore, the manufacturing method of the PCB board specifically includes:

[0026] Sub-board cutting—inner layer graphics—pressing—drilling—copper deposition—VCP electroplating—plated holes—resin plugging—second outer layer circuit—pressing—drilling—copper deposition—electroplating—outer layer circuit—solder mask—text—controlled depth drilling—gold deposition—appearance—electrical testing—FQC—FQA—packaging.

[0027] A third object of the present invention is to provide a PCB board, which is prepared by the above-mentioned PCB board manufacturing method.

[0028] By using the manufacturing method of the PCB board as described above, it is ensured that the manufactured PCB board has higher quality mechanical blind holes, thereby improving the overall performance and reliability of the PCB board.

[0029] The beneficial effects of the present invention are:

[0030] The present invention provides a method for making a mechanical blind hole, which includes prefabricating a first hole on a first sub-board whose size is larger than the final target blind hole, processing a conductive layer therein, and then combining it with a second sub-board to form a composite structure after filling, and finally processing the target blind hole on the composite structure. Since the size of the first hole is larger than the target blind hole, when processing the conductive layer in the first hole, there is more space, and it is easier to operate and control, so that a more uniform and thicker conductive layer can be obtained, avoiding the problem of no copper at the bottom of the hole. The filling material further enhances the stability of the structure in the first hole and provides support for subsequent depth-controlled drilling. The quality and reliability of the mechanical blind hole are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of a first hole provided in the present application;

[0032] Figure 2 is a schematic diagram of processing a conductive layer provided in this application;

[0033] Figure 3 is a schematic diagram of filling a first hole provided in the present application;

[0034] Figure 4 is a schematic diagram of a composite structure provided in the present application;

[0035] Figure 5 is a schematic diagram of a target blind hole provided in this application;

[0036] Figure 6 It is a flow chart of the method for making a mechanical blind hole provided in this application.

[0037] Reference numerals:

[0038] 100, first sub-board; 110, first hole; 120, conductive layer; 130, filling material;

[0039] 200, target blind hole;

[0040] 300. The second sub-board. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0042] Example 1

[0043] like Figures 1 to 6 As shown, this embodiment provides a method for manufacturing a mechanical blind hole, and the method for manufacturing a mechanical blind hole includes:

[0044] A first hole 110 is processed on the first sub-board 100 at a position corresponding to the target blind hole 200, and the size of the first hole 110 is larger than the size of the target blind hole 200;

[0045] In this embodiment, the target blind via 200 is a high aspect ratio mechanical blind via.

[0046] A conductive layer 120 is processed in the first hole 110, wherein the inner diameter of the conductive layer 120 is smaller than the diameter of the target blind hole 200;

[0047] In this embodiment, the conductive layer 120 is made of copper and is formed by electroplating.

[0048] Filling the first hole 110 with a filling material 130;

[0049] In this embodiment, the filling material 130 is resin.

[0050] Combining the first sub-panel 100 and the second sub-panel 300 to form a composite structure;

[0051] The target blind hole 200 is processed on the composite structure.

[0052] Specifically, processing the target blind hole 200 on the composite structure includes:

[0053] Controlled-depth drilling is performed on the composite structure at a position corresponding to the first hole 110 to expose the conductive layer 120 , thereby forming the target blind hole 200 .

[0054] More specifically, in this embodiment, a high aspect ratio mechanical blind hole with an aspect ratio of 5:1 is manufactured by this method, the diameter of the target blind hole 200 is 0.2 mm, and the depth of the target blind hole 200 is 1 mm.

[0055] The PCB board is split into two sub-boards. Since the target blind hole 200 has a depth of 1 mm, the thickness of the first sub-board 100 needs to be at least 1 mm. In this embodiment, the thickness of the first sub-board 100 is 1 mm, and the thickness of the second sub-board 300 is 1 mm.

[0056] A first hole 110 is processed on the first sub-board 100. The size of the first hole 110 needs to be larger than the size of the target blind hole 200. In this embodiment, a mechanical drill with a diameter of 0.25 mm is used to drill a hole at a position corresponding to the target blind hole 200 on the sub-board 1 to form a first hole 110 with a diameter of 0.25 mm.

[0057] A conductive layer 120 is processed in the first hole 110. The inner wall of the first hole 110 is copper-plated by electroplating process. The inner diameter of the conductive layer 120 is smaller than the aperture of the target blind hole 200. In other words, the thickness of the conductive layer 120 needs to be greater than 0.025 mm. In this embodiment, a copper layer with a thickness of 0.05 mm is formed as the conductive layer 120, and the inner diameter of the conductive layer 120 is.

[0058] Fill the first hole 110 with epoxy resin and cure it.

[0059] The sub-plates are pressed together to form a composite structure by pressing the first sub-plate 100 and the second sub-plate 300 together. The total thickness of the composite structure is 2 mm.

[0060] The target blind hole 200 is processed by using a mechanical drill bit with a diameter of 0.2 mm to perform controlled depth drilling on the composite structure with a drilling depth of 1 mm to expose the conductive layer 120 and form a final mechanical blind hole with an aspect ratio of 5:1.

[0061] The method for making a mechanical blind hole provided in this embodiment prefabricates a first hole 110 with a diameter of 0.25 mm on a first sub-board 100 with a thickness of 1 mm, and electroplates a copper layer with a thickness of 0.05 mm as a conductive layer 120 therein, and after filling, presses it with another second sub-board 300 with a thickness of 1 mm, and finally performs controlled depth drilling with a diameter of 0.2 mm, thereby realizing the production of a mechanical blind hole with an aspect ratio of 5:1. The difficulty of directly processing the conductive layer 120 in a blind hole with a high aspect ratio is effectively avoided. The larger initial hole diameter makes the electroplating operation easier to perform, and can ensure that the bottom of the hole obtains a sufficient copper layer thickness, avoiding the problem of no copper at the bottom of the hole. Finally, controlled depth drilling is performed to remove the excess copper layer and avoid the defect of rough hole wall, thereby improving the quality and reliability of the mechanical blind hole, which is particularly suitable for high-speed and high-frequency circuits.

[0062] Example 2

[0063] like Figures 1 to 6 As shown, this embodiment provides a method for manufacturing a mechanical blind hole, and the method for manufacturing a mechanical blind hole includes:

[0064] A first hole 110 is processed on the first sub-board 100 at a position corresponding to the target blind hole 200, and the size of the first hole 110 is larger than the size of the target blind hole 200;

[0065] In this embodiment, the target blind hole 200 has a diameter of 0.2 mm, a depth of 0.6 mm, and an aspect ratio of 3:1.

[0066] A conductive layer 120 is processed in the first hole 110, wherein the inner diameter of the conductive layer 120 is smaller than the size of the target blind hole 200;

[0067] In this embodiment, the conductive layer 120 is made of nickel-gold and is formed by chemical plating.

[0068] Filling the first hole 110 with a filling material 130;

[0069] In this embodiment, the filling material 130 is polyimide resin.

[0070] Combining the first sub-panel 100 and the second sub-panel 300 to form a composite structure;

[0071] In this embodiment, the thickness of the first sub-plate 100 is 0.8 mm, the thickness of the second sub-plate 300 is 1.6 mm, and the total thickness of the composite structure is 2.4 mm.

[0072] The target blind hole 200 is processed on the composite structure.

[0073] Specifically, processing the target blind hole 200 on the composite structure includes:

[0074] Controlled-depth drilling is performed on the composite structure at a position corresponding to the first hole 110 to expose the conductive layer 120 , thereby forming the target blind hole 200 .

[0075] More specifically, in this embodiment, a laser drilling technique is used on the first sub-board 100 to form a first hole 110 with a diameter of 0.25 mm. Then, a nickel-gold conductive layer 120 is formed on the inner wall of the first hole 110 by a chemical nickel-gold plating process. The first hole 110 is filled with a polyimide resin. Finally, a mechanical drill bit with a diameter of 0.2 mm is used to perform controlled depth drilling on the composite structure, with a drilling depth of 0.6 mm, to form a final mechanical blind hole with an aspect ratio of 3:1.

[0076] Compared with traditional mechanical drilling, the method for making mechanical blind holes provided in this embodiment can process holes with smaller diameters and obtain higher precision through laser drilling. The chemical nickel-gold plating process does not require external current and can form a uniform metal coating on non-conductive materials, which is suitable for holes of various complex shapes. It effectively improves the production efficiency and precision of mechanical blind holes and is suitable for high-frequency circuits with high surface treatment requirements.

[0077] Example 3

[0078] like Figures 1 to 6 As shown, this embodiment provides a method for manufacturing a mechanical blind hole, and the method for manufacturing a mechanical blind hole includes:

[0079] A first hole 110 is processed on the first sub-board 100 at a position corresponding to the target blind hole 200, and the size of the first hole 110 is larger than the size of the target blind hole 200;

[0080] In this embodiment, the target blind hole 200 has a diameter of 0.18 mm, a depth of 1.8 mm, and an aspect ratio of 10:1, and is a high aspect ratio mechanical blind hole.

[0081] A conductive layer 120 is processed in the first hole 110, wherein the inner diameter of the conductive layer 120 is smaller than the size of the target blind hole 200;

[0082] In this embodiment, the conductive layer 120 is made of silver and is formed by electroplating.

[0083] Filling the first hole 110 with a filling material 130;

[0084] In this embodiment, the filling material 130 is a liquid photosensitive resin that is cured by ultraviolet light.

[0085] Combining the first sub-panel 100 and the second sub-panel 300 to form a composite structure;

[0086] In this embodiment, the thickness of the first sub-board 100 is 2 mm, the thickness of the second sub-board 300 is 8 mm, and the sub-boards 1 and 2 are pressed together using vacuum pressing technology, and the total thickness of the composite structure is 10 mm.

[0087] The target blind hole 200 is processed on the composite structure.

[0088] Specifically, processing the target blind hole 200 on the composite structure includes:

[0089] Controlled-depth drilling is performed on the composite structure at a position corresponding to the first hole 110 to expose the conductive layer 120 , thereby forming the target blind hole 200 .

[0090] More specifically, in this embodiment, a micro drill bit with a diameter of 0.2 mm is used to form a first hole 110 with a diameter of 0.2 mm on the first sub-board. The inner wall of the first hole 110 is plated with silver by electroplating to form a silver layer with a thickness of 10 μm as the conductive layer 120. The first hole 110 is filled with liquid photosensitive resin and cured with ultraviolet light. Finally, a micro drill bit with a diameter of 0.18 mm is used to perform controlled depth drilling on the composite structure, with a drilling depth of 1.8 mm, to form a final mechanical blind hole with an aspect ratio of 10:1.

[0091] The method for making a mechanical blind hole provided in this embodiment uses precision processes such as micro-drilling and vacuum pressing to ensure the processing accuracy and structural stability of high aspect ratio blind holes. The silver layer as the conductive layer 120 has a lower resistivity and can further improve the signal transmission performance. Liquid photosensitive resin and ultraviolet light curing technology improve the bonding strength between the filling material 130 and the hole wall. It is suitable for PCB boards with extremely high requirements for interconnection density and signal transmission performance.

[0092] Example 4

[0093] This embodiment provides a method for manufacturing a PCB board, and the method includes the method for manufacturing a mechanical blind via as described above, and specifically includes:

[0094] Sub-board cutting—inner layer graphics—pressing—drilling—copper deposition—VCP electroplating—plated holes—resin plugging—second outer layer circuit—pressing—drilling—copper deposition—electroplating—outer layer circuit—solder mask—text—controlled depth drilling—gold deposition—appearance—electrical testing—FQC—FQA—packaging.

[0095] More specifically, cutting: cutting large-size substrate materials into small-size core boards that meet the PNL size of the PCB board;

[0096] Inner layer graphics: Use the principle of optical imaging to make the circuit graphics required by customers on the inner core board;

[0097] Lamination: Arrange the stacked boards in order of layers, and add prepreg PP between each copper base according to customer requirements. The prepreg is completely cured by high temperature and high pressure using a press, so that all layers of copper base are pressed into a semi-finished PCB with a sequential structure. The pressed PP flow glue will fill the line spacing area. After lamination, a ceramic grinding plate is used to grind off the PP glue overflowing from the spacing.

[0098] Drilling: Drill holes on the PCB board that need to conduct the inner layer circuits, and deal with the burrs on the hole openings;

[0099] Copper deposition: Copper is deposited on the PCB surface and in the holes using chemical methods to create a conductive effect.

[0100] Electroplating: Based on copper deposition, the hole copper and surface copper are electroplated to thicken them so that the surface copper and hole copper meet customer needs.

[0101] Hole plating: Graphic electroplating only plates hole copper. Thicken the hole copper to the required range.

[0102] Resin plugging: Use a vacuum plugging machine to plug the resin into the hole. The hole must be fully filled with resin.

[0103] Sub-outer circuit: Use the principle of optical imaging to make the circuit pattern required by the customer on the sub-outer core board

[0104] Solder mask: Print a layer of ink on the PCB surface to protect it;

[0105] Text: Print the text and logo required by the customer on the outer layer of the PCB;

[0106] Controlled depth drilling: Use a mechanical drilling machine, set the drilling depth, and use the required drill bit to drill mechanical blind holes on the PCB board.

[0107] Immersion Gold: A thin layer of gold is plated on the circuit pattern to protect the circuit;

[0108] Electrical test: perform open and short circuit tests on the PCB to detect the conduction performance;

[0109] Molding: produce the finished PCB graphics of the size required by the customer;

[0110] The PCB board manufacturing method provided in this embodiment solves the problem that high aspect ratio mechanical blind vias are difficult to process reliably in the prior art, and achieves compatibility between high aspect ratio mechanical blind vias and PCB board manufacturing processes. The PCB board finally manufactured includes high-quality and high-reliability high aspect ratio mechanical blind vias, which can meet the signal integrity requirements of high-speed and high-frequency circuits and improve the overall performance of the PCB board.

[0111] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a restriction. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in the subsequent accompanying drawings.

[0112] In addition, it should be noted that the use of terms such as "first" and "second" to limit is only for the convenience of distinction. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for making a mechanical blind hole, characterized in that: include: Processing a first hole (110) at a position corresponding to the target blind hole (200) on the first sub-plate (100), wherein the size of the first hole (110) is larger than the size of the target blind hole (200); Processing a conductive layer (120) in the first hole (110), wherein the inner diameter of the conductive layer (120) is smaller than the diameter of the target blind hole (200); Filling the first hole (110) with a filling material (130); Combining the first sub-panel (100) and the second sub-panel (300) to form a composite structure; The target blind hole (200) is machined on the composite structure.

2. The method for making a mechanical blind via according to claim 1, characterized in that: The step of machining the target blind hole (200) on the composite structure comprises: Controlled-depth drilling is performed on the composite structure at a position corresponding to the first hole (110) to expose the conductive layer (120) and form the target blind hole (200).

3. The method for making a mechanical blind via according to claim 1, characterized in that: The target blind via (200) is a high aspect ratio mechanical blind via.

4. The method for making a mechanical blind via according to claim 1, characterized in that: The conductive layer (120) is made of metal.

5. The method for making a mechanical blind via according to claim 4, characterized in that: The conductive layer (120) is made of copper.

6. The method for making a mechanical blind via according to claim 4, characterized in that: The conductive layer (120) is formed by electroplating.

7. The method for making a mechanical blind via according to claim 1, characterized in that: The filling material (130) is resin.

8. A method for manufacturing a PCB board, characterized in that: A method for manufacturing a mechanical blind hole comprising the steps of any one of claims 1 to 7.

9. The method for manufacturing a PCB board according to claim 8, characterized in that: The manufacturing method of the PCB board specifically includes: Sub-board cutting—inner layer graphics—pressing—drilling—copper deposition—VCP electroplating—plated holes—resin plugging—second outer layer circuit—pressing—drilling—copper deposition—electroplating—outer layer circuit—solder mask—text—controlled depth drilling—gold deposition—appearance—electrical testing—FQC—FQA—packaging.

10. A PCB board, characterized in that: The PCB board is prepared by the manufacturing method of claim 8.

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