Circuit board jump layer blind hole manufacturing method, circuit board and electronic equipment

Abstract

The invention discloses a circuit board jump layer blind hole manufacturing method, a circuit board and electronic equipment, a target inner layer circuit layer of a target circuit board to be manufactured is provided with a laser target used for calibrating the position of a jump layer blind hole, a first window is formed in the target circuit board, the laser target is exposed, a first mask layer is formed on a surface layer circuit layer, and a second window is formed on the surface layer circuit layer; taking the laser target as position calibration, exposing and developing the first mask layer, forming a second window corresponding to the jump layer blind hole on the first mask layer, exposing the surface circuit layer, removing part of the surface circuit layer exposed by the second window, exposing the base material, and taking the laser target as position calibration; laser drilling is adopted to remove part of the target circuit board at the same position of the second window, form a third window, expose the target inner circuit layer, remove the first mask layer, form a metal coating on the inner wall of the third window, and form a jump layer blind hole for connecting the surface circuit layer and the target inner circuit layer, so that the position precision of the jump layer blind hole can be improved, and the quality of the product is improved. And the quality of the circuit board is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chip processing, and particularly to a method for manufacturing a skip via of a circuit board, a circuit board, and an electronic device. Background Art

[0002] A high density interconnector (HDI) is a printed circuit board (PCB) manufactured using a higher density wiring technology. Through smaller aperture, finer line width / spacing, and more layers of blind and buried via technologies, miniaturization, lightweight, and higher wiring density of the circuit board are achieved.

[0003] A common blind via in a high density interconnector is a skip via, which is mainly used to connect the surface layer circuit and non-adjacent inner layer circuits. The aperture of the skip via is relatively large (generally ≥8 mil). Limited by the aperture processing ability of a laser drilling machine, it cannot be manufactured by directly laser after brownification. Therefore, it is usually manufactured by means of graphic transfer and etching. The manufacturing process is as follows: target holes for position calibration are formed on the circuit board, a dry film is attached to the surface of the circuit board, and then, using these target holes as position calibration, exposure and development are carried out to transfer the pattern of the skip via to the dry film. Then, the surface copper foil at the same position of the pattern of the skip via is etched to expose the substrate. Again, using the target holes as position calibration, a laser drill is used to remove the intermediate layer at the same position above the inner layer circuit to be connected, forming a blind via. Then, an electroplated layer is formed on the inner wall of the blind via to obtain a skip via connecting the surface layer circuit and non-adjacent inner layer circuits.

[0004] When manufacturing a skip via, the target holes need to be used twice for position calibration. The position of the target holes is formed based on the average expansion and contraction data of all layers, rather than the expansion and contraction data of the layer where the skip via is located. When the difference in expansion and contraction data between layers is large, resulting in interlayer misalignment, when graphic transfer is carried out using these target holes as position calibration, and when laser drilling is carried out using these target holes as position calibration, large position deviations will occur, resulting in misalignment of the finally formed blind via, which may lead to incorrect electrical connection between layers. In addition, when drilling the target holes during thick plate lamination, burrs and flash will inevitably appear on the target holes, and the target holes are not round. It is necessary to manually fit and round the target holes grabbed by the machine, and manual operation often has great uncertainty, which will also cause position deviations in graphic transfer and laser drilling, resulting in misalignment of the finally formed blind via, which may lead to incorrect electrical connection between layers. Summary of the Invention

[0005] The present invention provides a method for manufacturing a skip via of a circuit board, a circuit board, and an electronic device, which can improve the position accuracy of the skip via and improve the quality of the circuit board.

[0006] In a first aspect, the present invention provides a method for manufacturing a circuit board skip-layer blind via, including:

[0007] Providing a target circuit board to be manufactured, the target circuit board includes multiple circuit layers, and on the target inner circuit layer to be connected to the surface circuit layer in the target circuit board, a laser target for calibrating the position of the skip-layer blind via is provided;

[0008] Forming a first opening window on the target circuit board to expose the laser target;

[0009] Forming a first mask layer on the surface circuit layer;

[0010] Using the laser target as a position calibration, exposing and developing the first mask layer, and forming a second opening window corresponding to the skip-layer blind via on the first mask layer to expose the surface circuit layer;

[0011] Removing a part of the surface circuit layer exposed by the second opening window to expose the substrate;

[0012] Using the laser target as a position calibration, removing a part of the target circuit board at the same position as the second opening window by laser drilling to form a third opening window to expose the target inner circuit layer, and removing the first mask layer, where the same position is the position where the vertical projections in each layer overlap;

[0013] Forming a metal coating on the inner wall of the third opening window to form a skip-layer blind via connecting the surface circuit layer and the target inner circuit layer.

[0014] Optionally, forming a first opening window on the target circuit board to expose the laser target includes:

[0015] Forming a second mask layer on the surface circuit layer;

[0016] Exposing and developing the second mask layer, and forming a fourth opening window corresponding to the laser target on the second mask layer to expose the surface circuit layer;

[0017] Removing a part of the surface circuit layer exposed by the fourth opening window to expose the substrate;

[0018] Removing a part of the target circuit board at the same position as the fourth opening window by laser drilling to form a first opening window to expose the laser target, and removing the second mask layer.

[0019] Optionally, the vertical projection of the laser target on the target circuit board is within the vertical projection of the first opening window on the target circuit board.

[0020] Optionally, at least two sets of the laser targets are provided on the target inner circuit layer;

[0021] Using the first set of laser targets as position calibration, expose and develop the first mask layer to form a second opening corresponding to the skip layer blind via on the first mask layer, exposing the surface circuit layer;

[0022] Using the second set of laser targets as position calibration, use laser drilling to remove a part of the target circuit board at the same position as the second opening, forming a third opening to expose the target inner circuit layer.

[0023] Optionally, before providing the target circuit board to be manufactured, it further includes:

[0024] While preparing the circuit of the target inner circuit layer on the inner core board, form laser targets for calibrating the positions of the skip layer blind vias on the target inner circuit layer;

[0025] Press multiple circuit layers together to form the target circuit board to be manufactured.

[0026] Optionally, the laser targets are located in the edge area of the target inner circuit layer, and no circuits are provided at the same positions of the laser targets on each circuit layer.

[0027] Optionally, no circuits are provided at the same positions corresponding to the skip layer blind vias on the intermediate circuit layer between the surface circuit layer and the target inner circuit layer.

[0028] Optionally, the aperture of the skip layer blind via is greater than or equal to 6 mil.

[0029] In a second aspect, the present invention also provides a circuit board prepared by using the method for manufacturing skip layer blind vias of the circuit board provided in the first aspect of the present invention.

[0030] In a third aspect, the present invention also provides an electronic device including the circuit board provided in the second aspect of the present invention.

[0031] The manufacturing method of the skip-layer blind vias of the circuit board provided by the present invention is as follows. On the target inner-layer circuit layer of the target circuit board to be manufactured, there is a laser target for calibrating the positions of the skip-layer blind vias. A first opening window is formed on the target circuit board to expose the laser target. A first mask layer is formed on the surface circuit layer. Using the laser target as the position calibration, the first mask layer is exposed and developed, and a second opening window corresponding to the skip-layer blind vias is formed on the first mask layer, exposing the surface circuit layer. The part of the surface circuit layer exposed by the second opening window is removed to expose the base material. Using the laser target as the position calibration, a part of the target circuit board at the same position as the second opening window is removed by laser drilling to form a third opening window, exposing the target inner-layer circuit layer, and the first mask layer is removed. A metal coating is formed on the inner wall of the third opening window to form the skip-layer blind vias connecting the surface circuit layer and the target inner-layer circuit layer. Since the position of the laser target is formed based on the expansion and contraction data of the target inner-layer circuit layer, even if there is an interlayer offset in other circuit layers, it does not affect the position accuracy of exposure and laser drilling, improving the position accuracy of the skip-layer blind vias and the quality of the circuit board. In addition, the problem of burrs and flash on the target holes generated by drilling the target is avoided, and there is no need for manual fitting to obtain a circle, improving the position accuracy of the skip-layer blind vias and the quality of the circuit board. Brief Description of the Drawings

[0032] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0033] Figure 1 It is a process flow chart of a manufacturing method of the skip-layer blind vias of a circuit board provided by the present invention;

[0034] Figure 2 It is a process flow chart of forming a first opening window provided by the present invention;

[0035] Figure 3 It is a schematic diagram of a laser target on a target inner-layer circuit layer provided by the present invention. Detailed Embodiments

[0036] To make the technical problems solved by the present invention, the technical solutions adopted, and the achieved technical effects clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0037] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0038] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above and over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under and beneath", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0039] Figure 1 The process flow diagram of a method for manufacturing a circuit board skip-layer blind hole provided by the present invention is as Figure 1 shown. The method for manufacturing the circuit board skip-layer blind hole includes the following steps:

[0040] S101. Provide a target circuit board to be manufactured.

[0041] Exemplarily, the target circuit board for manufacturing the skip-layer blind hole includes multiple circuit layers (for example, more than 30 layers). In this embodiment, 5 of the layers of the target circuit board are exemplarily drawn and are sequentially L1 to L5 from top to bottom for illustration. The adjacent circuit layers are isolated by an insulating substrate. A laser target 11 for calibrating the position of the skip-layer blind hole is provided on the target inner circuit layer L3 to be connected to the surface circuit layer L1 of the target circuit board. In other embodiments of the present invention, the target inner circuit layer may also be other inner circuit layers, and the present invention does not make any limitation here.

[0042] Exemplarily, the laser target 11 is usually a symmetric geometric figure, such as a crosshair, a circle, a square, etc., with high contrast, facilitating the recognition by the optical system. Exemplarily, the laser target 11 can be printed on the target inner layer circuit layer L3 using ink. In the embodiment of the present invention, the laser target 11 is used to calibrate the position of the skip-layer blind via. In the subsequent exposure and laser drilling processes, the optical system grabs the laser target 11, identifies the center position or edge of the laser target 11 through an image processing algorithm, calculates its precise coordinates, and thus determines the exposure position and the laser drilling position according to the position of the laser target 11.

[0043] In some embodiments of the present invention, while preparing the circuit of the target inner layer circuit layer L3 on the inner layer core board, a laser target 11 for calibrating the position of the skip-layer blind via can be formed on the target inner layer circuit layer L3, then other circuit layers are prepared, and finally multiple circuit layers are laminated to form the target circuit board to be fabricated.

[0044] It should be noted that the various circuit layers of the target circuit board can be electrically connected through through-holes, blind vias, and buried vias, Figure 1 which are not shown again, Figure 1 and only the content related to fabricating the skip-layer blind via in this solution is shown.

[0045] S102. Form a first opening window on the target circuit board to expose the laser target.

[0046] In the embodiment of the present invention, a first opening window 12 is formed on the target circuit board to expose the laser target 11. In the embodiment of the present invention, the manner of forming the first opening window is not limited.

[0047] In the embodiment of the present invention, the vertical projection of the laser target 11 on the target circuit board is within the vertical projection of the first opening window 12 on the target circuit board, that is, the first opening window 12 needs to completely expose the laser target 11 to prevent deviation of the subsequent exposure position and laser drilling position due to the optical system's inability to recognize the laser target 11.

[0048] In some embodiments of the present invention, a mechanical drilling method can be used to remove a part of the target circuit board at the same position as the laser target 11 to form a first opening window 12 on the target circuit board to expose the laser target 11. Since the aperture of the first opening window 12 can be set relatively large, even if the first opening window 12 formed by mechanical drilling has burrs and flash, it does not affect the optical system's grasping of the laser target 11.

[0049] In another embodiment of the present invention, in order to reduce the burrs and flash on the first opening 12 and improve the recognition accuracy of the laser target 11, a laser drilling method can be used to form the first opening. In the embodiment of the present invention, a CO2 laser is used during the laser drilling process, and the laser generated by the excitation of CO2 molecules is used for drilling. Since the absorption rate of copper metal layer for CO2 is very low, therefore, it is necessary to first remove the metal layer at the position corresponding to the first opening on the surface circuit layer. Figure 2 The process flow chart of forming the first opening provided by the present invention is as Figure 2 shown, and the forming steps of the first opening include:

[0050] S1021. Form a second mask layer on the surface circuit layer.

[0051] Exemplarily, in the embodiment of the present invention, the surface circuit layer L1 can be first subjected to chemical or mechanical pretreatment to remove the oil stain and oxide layer on the surface of the surface circuit layer L1, form a microscopically rough surface, and improve the bonding strength between the surface circuit layer L1 and the second mask layer to be attached. Then, a second mask layer 101 is formed on the surface circuit layer L1. The second mask layer 101 can be a dry film sensitive to light of a specific wavelength band (such as ultraviolet light). In actual operation, only need to attach the dry film to the surface circuit layer L1.

[0052] S1022. Expose and develop the second mask layer to form a third opening corresponding to the laser target on the second mask layer, exposing the surface circuit layer.

[0053] In the embodiment of the present invention, the area corresponding to the laser target 11 on the second mask layer 101 is shielded from light, and the remaining areas are exposed. Since the first opening 12 only needs to completely expose the laser target 11, therefore, during the process of exposing the second mask layer 101, there is no requirement for particularly precise exposure position, as long as the shielded area completely covers the position corresponding to the laser target 11.

[0054] After exposing the second mask layer 101, a developer is used to develop the second mask layer 101 to remove the unexposed areas, and a fourth opening 13 corresponding to the laser target 11 is formed on the second mask layer 101, exposing the surface circuit layer L1.

[0055] S1023. Remove the part of the surface circuit layer exposed by the fourth opening to expose the substrate.

[0056] In the embodiment of the present invention, the part of the surface circuit layer L1 exposed by the fourth opening 13 is removed by etching to expose the substrate below the surface circuit layer L1.

[0057] S1024. Use laser drilling to remove part of the target circuit board at the same position as the fourth opening window, form a first opening window to expose the laser target, and remove the second mask layer.

[0058] In an embodiment of the present invention, use laser drilling to remove part of the target circuit board at the same position as the fourth opening window 13, form a first opening window 12 to expose the laser target 11, and remove the second mask layer 101. In an embodiment of the present invention, a CO2 laser is used during the laser drilling process, and the laser generated by the excitation of CO2 molecules is used for drilling.

[0059] In some embodiments of the present invention, the laser target 11 is located in the edge area of the target inner layer circuit layer L3, and no circuit is provided at the same position of the laser target 11 on each circuit layer. Since the absorption rate of metal copper layer to CO2 is very low, no circuit is provided at the same position of the laser target 11 on each circuit layer to ensure that the CO2 laser processing of the first opening window 12 can expose the laser target 11. Wherein, the same position described in the present invention is the position where the vertical projections on each layer overlap. Exemplarily, the same position of the laser target 11 on each circuit layer is the position where the vertical projection overlaps with the laser target 11 on each layer.

[0060] S103. Form a first mask layer on the surface circuit layer.

[0061] After the laser target 11 is exposed, the surface circuit layer L1 can be chemically or mechanically pretreated first to remove the oil stain and oxide layer on the surface of the surface circuit layer L1, form a microscopically rough surface, and improve the bonding strength between the surface circuit layer L1 and the first mask layer to be attached. After the chemical or mechanical pretreatment, a first mask layer 102 is formed on the surface circuit layer L1. The first mask layer 102 can be a dry film sensitive to light of a specific wavelength band (such as ultraviolet light). It should be noted that the first mask layer 102 is opened at the position where the first opening window 12 is located to expose the first opening window 12.

[0062] S104. Using the laser target as a position calibration, expose and develop the first mask layer to form a second opening window corresponding to the skip layer blind hole on the first mask layer, exposing the surface circuit layer.

[0063] In an embodiment of the present invention, the optical system grabs the laser target 11, uses the laser target 11 as a position calibration to determine the exposure area and the light-shielding area, and exposes the first mask layer 102. Exemplarily, the area corresponding to the skip layer blind hole on the first mask layer 102 is shielded from light, and the rest of the area is exposed.

[0064] After exposing the first mask layer 102, use a developer to develop the first mask layer 102 to remove the unexposed area, and form a second opening window 14 corresponding to the skip layer blind hole on the first mask layer 102, exposing the surface circuit layer L1.

[0065] S105. Remove the exposed part of the surface circuit layer in the second opening window to expose the substrate.

[0066] In the embodiment of the present invention, the exposed part of the surface circuit layer L1 in the second opening window 14 is removed by etching to expose the substrate below the surface circuit layer L1.

[0067] S106. Using the laser target as a position calibration, remove a part of the target circuit board at the same position as the second opening window by laser drilling to form a third opening window, expose the target inner circuit layer, and remove the first mask layer. The same position refers to the position where the vertical projections in each layer overlap.

[0068] In the embodiment of the present invention, the optical system grabs the laser target 11, uses the laser target 11 as a position calibration, removes a part of the target circuit board at the same position as the second opening window 14 by laser drilling to form a third opening window 15, exposes the target inner circuit layer L3, and removes the first mask layer 102.

[0069] In the embodiment of the present invention, a CO2 laser is used during the laser drilling process, and the laser generated by the excitation of CO2 molecules is used for drilling. In the embodiment of the present invention, since the absorption rate of the metal copper layer to CO2 is very low, no circuit is provided at the same position corresponding to the skip-layer blind hole in the intermediate circuit layer between the surface circuit layer and the target inner circuit layer, ensuring that the formed third opening window 15 can expose the target inner circuit layer L3.

[0070] S107. Form a metal coating on the inner wall of the third opening window to form a skip-layer blind hole connecting the surface circuit layer and the target inner circuit layer.

[0071] After forming the third opening window 15, a metal coating 151 is formed on the inner wall of the third opening window 15 by electroplating to form a skip-layer blind hole connecting the surface circuit layer L1 and the target inner circuit layer L3.

[0072] In some embodiments of the present invention, the aperture of the skip-layer blind hole is greater than or equal to 6 mil. In the embodiment of the present invention, the skip-layer blind hole is a conical hole, and the aperture of the skip-layer blind hole refers to the diameter of the large end.

[0073] In some embodiments of the present invention, at least two sets of laser targets are provided on the target inner circuit layer. Figure 3 This is a schematic diagram of the laser target on the target inner circuit layer provided by the present invention. As Figure 3 shown, two sets of laser targets are provided on the target inner circuit layer, namely the first set of laser targets 111 and the second set of laser targets 112. Both sets of laser targets are located in the edge area of the target inner circuit layer L3.

[0074] In the above step S104, using the first set of laser targets 111 as the position calibration, the first mask layer 102 is exposed and developed, and a second opening 14 corresponding to the skip-layer blind hole is formed on the first mask layer 102, exposing the surface circuit layer L1. The exposure and development processes can refer to the above step S104, and will not be elaborated in this embodiment.

[0075] In the above step S105, the exposed part of the surface circuit layer L1 exposed by the second opening 14 is removed by etching, exposing the substrate below the surface circuit layer L1. During this process, since the first set of laser targets 111 is also exposed, the first set of laser targets 111 will also be etched away.

[0076] In the above step S106, using the second set of laser targets 112 as the position calibration, a part of the target circuit board at the same position as the second opening 14 is removed by laser drilling to form a third opening 15, exposing the target inner layer circuit layer L3.

[0077] In this embodiment, at least two sets of laser targets are provided for the purpose that: since one set of laser targets will be etched away in step S105, at least one additional set of laser targets is required for the position calibration of the laser drilling in step S106.

[0078] Of course, in other embodiments of the present invention, only one set of laser targets can also be provided. The first opening 12 is temporarily sealed before the etching step of step S105 to prevent the laser targets from being etched away. When performing step S106, the first opening 12 is opened again to expose the laser targets.

[0079] The manufacturing method of the skip-layer blind vias of the circuit board provided by the present invention is as follows: on the target inner-layer circuit layer of the target circuit board to be manufactured, there is a laser target for calibrating the positions of the skip-layer blind vias. A first opening window is formed on the target circuit board to expose the laser target. A first mask layer is formed on the surface circuit layer. Using the laser target as the position calibration, the first mask layer is exposed and developed, and a second opening window corresponding to the skip-layer blind vias is formed on the first mask layer, exposing the surface circuit layer. The part of the surface circuit layer exposed by the second opening window is removed to expose the base material. Using the laser target as the position calibration, a part of the target circuit board at the same position as the second opening window is removed by laser drilling to form a third opening window, exposing the target inner-layer circuit layer, and the first mask layer is removed. A metal coating is formed on the inner wall of the third opening window to form the skip-layer blind vias connecting the surface circuit layer and the target inner-layer circuit layer. Since the position of the laser target is formed based on the shrinkage data of the target inner-layer circuit layer, even if there is an interlayer offset in other circuit layers, it does not affect the position accuracy of the surface circuit opening window and laser drilling, improving the position accuracy of the skip-layer blind vias and the quality of the circuit board. In addition, the problem of burrs and flash on the target holes generated by drilling the target is avoided, and there is no need for manual fitting to obtain a circle, improving the position accuracy of the skip-layer blind vias and the quality of the circuit board.

[0080] The present invention also provides a circuit board, which is prepared by using the manufacturing method of the skip-layer blind vias of the circuit board provided in any of the foregoing embodiments of the present invention, and has the same effects as the foregoing embodiments.

[0081] The present invention also provides an electronic device, which includes the circuit board provided by the present invention.

[0082] In the description herein, it should be understood that the orientation or positional relationships such as "upper", "lower", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operations, 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 thus should not be construed as a limitation of the present invention.

[0083] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0084] In addition, it should be understood that although this specification is described according to the embodiments, not each embodiment only includes an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0085] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the scope of protection of the present invention.

Claims

1. A manufacturing method for skip-layer blind vias of a circuit board, characterized in that, Comprising: Providing a target circuit board to be fabricated, the target circuit board comprising multiple circuit layers, and a laser target for calibrating the position of a skip-layer blind via being disposed on a target inner circuit layer of the target circuit board that is to be connected to a surface circuit layer; Forming a first opening window on the target circuit board to expose the laser target; Forming a first mask layer on the surface circuit layer; Using the laser target as a position calibration, exposing and developing the first mask layer, and forming a second opening window corresponding to the skip-layer blind via on the first mask layer to expose the surface circuit layer; Removing a part of the surface circuit layer exposed by the second opening window to expose the substrate; Using the laser target as a position calibration, removing a part of the target circuit board at the same position as the second opening window by laser drilling to form a third opening window to expose the target inner circuit layer, and removing the first mask layer, where the same position is the position where the vertical projections in each layer overlap; Forming a metal plating layer on the inner wall of the third opening window to form a skip-layer blind via connecting the surface circuit layer and the target inner circuit layer.

2. The manufacturing method of the circuit board skip-layer blind hole according to claim 1, characterized in that, Forming a first opening window on the target circuit board to expose the laser target, comprising: Forming a second mask layer on the surface circuit layer; Exposing and developing the second mask layer, and forming a fourth opening window corresponding to the laser target on the second mask layer to expose the surface circuit layer; Removing a part of the surface circuit layer exposed by the fourth opening window to expose the substrate; Removing a part of the target circuit board at the same position as the fourth opening window by laser drilling to form a first opening window to expose the laser target, and removing the second mask layer.

3. The manufacturing method of the circuit board skip-layer blind hole according to claim 1 or 2, characterized in that, The vertical projection of the laser target on the target circuit board is within the vertical projection of the first opening window on the target circuit board.

4. The manufacturing method of the circuit board skip-layer blind hole according to claim 1 or 2, characterized in that, At least two sets of the laser targets are disposed on the target inner circuit layer; Using the first set of the laser targets as a position calibration, exposing and developing the first mask layer, and forming a second opening window corresponding to the skip-layer blind via on the first mask layer to expose the surface circuit layer; Using the second set of the laser targets as a position calibration, removing a part of the target circuit board at the same position as the second opening window by laser drilling to form a third opening window to expose the target inner circuit layer.

5. The manufacturing method of the circuit board skip-layer blind hole according to claim 1 or 2, characterized in that Before providing the target circuit board to be fabricated, further comprising: While preparing the circuit of the target inner circuit layer on an inner core board, forming a laser target for calibrating the position of a skip-layer blind via on the target inner circuit layer; Pressing multiple circuit layers to form the target circuit board to be fabricated.

6. The manufacturing method of the circuit board skip-layer blind hole according to claim 1 or 2, characterized in that, The laser target is located in the edge region of the target inner circuit layer, and no circuit is provided at the same position of the laser targets on each circuit layer.

7. The manufacturing method of the circuit board skip-layer blind hole according to claim 1 or 2, characterized in that No circuit is provided at the same position corresponding to the skip-layer blind via on the intermediate circuit layer between the surface circuit layer and the target inner circuit layer.

8. The manufacturing method of the circuit board skip-layer blind hole according to claim 1 or 2, characterized in that, The aperture of the skip-layer blind via is greater than or equal to 6 mil.

9. A circuit board, characterized in that, Prepared by using the method for fabricating a skip-layer blind via of a circuit board according to any one of claims 1-8.

10. An electronic device, characterized in that, Comprising a circuit board according to claim 9.

Images