Layer deviation detection structure of multilayer printed circuit board

Abstract

The utility model discloses a layer deviation detection structure of a multilayer printed circuit board, which is characterized in that when layer deviation detection is carried out on an mth core board, only a first probe needs to be inserted into a first detection hole, a second probe is inserted into a second detection hole corresponding to the mth core board, and the layer deviation of the mth core board is detected by judging the electric connection state between the first probe and the second probe. The method is simple to operate, and is beneficial to quickly detecting the layer deviation of each layer of the multi-layer printed circuit board.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit board manufacturing, and particularly relates to a layer deviation detection structure for a multi-layer printed circuit board. Background Art

[0002] In the production and manufacturing process of a multi-layer printed circuit board, multiple copper clad laminates need to be laminated together through prepregs to form the multi-layer structure of the circuit board. However, during the lamination process of the multi-layer printed circuit board, under the action of pressure, position offset will occur between layers. If the position offset is large, it will affect the electrical connectivity between layers of the circuit board, and even cause open circuit or short circuit between layers, seriously affecting the quality of the circuit board. Therefore, it is usually necessary to detect the interlayer offset (layer deviation) of the laminated circuit board, so as to control the layer deviation of each layer of the shipped circuit board within a certain range.

[0003] In the prior art, generally, the layer deviation of the circuit board is detected and analyzed by slicing. However, this method usually requires detection under a microscope, with complex operation, low efficiency, and the need for visual judgment by the detection personnel, which has the risk of misjudgment. In addition, the sliced circuit board has been damaged and can only be scrapped. The detection result obtained by slicing can only represent the layer deviation of the specific sliced circuit board, and thus cannot confirm the layer deviation of other unsliced circuit boards. Therefore, the layer deviation quality of the product still cannot be guaranteed during shipment, and there are relatively large quality hazards. Summary of the Utility Model

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the utility model provides a layer deviation detection structure for a multi-layer printed circuit board, which can quickly detect the layer deviation of each layer of the multi-layer printed circuit board.

[0005] The layer deviation detection structure of a multi-layer printed circuit board according to an embodiment of the present utility model includes: n core boards, where n > 1 and n is an integer. The core board includes an insulating layer and an inner metal layer on the surface of the insulating layer. Each inner metal layer has a first detection area and a second detection area. The first detection area has at least one first detection point, and a first isolation groove is provided on the outer periphery of the first detection point, and the first isolation groove extends to the insulating layer. There are n second detection points in the second detection area, and the n second detection points correspond to the n core boards one by one. A second isolation groove extending to the insulating layer is provided in the second detection area. In the m-th core board, 1 ≤ m ≤ n and m is an integer, the second detection point corresponding to the m-th core board is located outside the second isolation groove, and the other second detection points are located inside the second isolation groove; two outer metal layers are correspondingly laminated on the opposite sides of the n core boards to form a multi-layer board, and a dielectric layer is provided between the outer metal layer and the adjacent core board; at least one of the outer metal layers is provided with first detection holes corresponding to all the first detection points in the first detection area, the first detection holes penetrate through the multi-layer board, and the radius of the first detection hole is smaller than the radius of the corresponding first isolation groove; a first metal layer extending to the two outer metal layers is further provided on the inner wall of the first detection hole, and each outer metal layer is further provided with a third isolation groove extending to the corresponding dielectric layer, and the first detection hole is located in the third isolation groove; at least one of the outer metal layers is provided with second detection holes corresponding to all the second detection points in the second detection area, the second detection holes penetrate through the multi-layer board, the second detection holes penetrate through the corresponding second detection points on each core board and are located in the corresponding second isolation grooves, a second metal layer extending to the two outer metal layers is further provided on the inner wall of the second detection hole, and each outer metal layer is further provided with a fourth isolation groove extending to the corresponding dielectric layer, and the second detection hole is located in the second isolation groove.

[0006] The layer deviation detection structure of a multi-layer printed circuit board according to an embodiment of the present utility model has at least the following beneficial effects:

[0007] By adopting the layer deviation detection structure of the multi-layer printed circuit board according to the embodiment of the present invention, in the m-th core board, where 1 ≤ m ≤ n and m is an integer, the second detection point corresponding to the m-th core board is located outside the second isolation groove, while on other core boards, the second detection point corresponding to the m-th core board is located inside the second isolation groove. Thus, the second detection hole corresponding to the m-th core board will penetrate through the inner metal layer of the m-th core board and through the second isolation groove of other core boards. That is, in the second detection hole corresponding to the m-th core board, the second metal layer is in contact conduction with the inner metal layer of the m-th core board, and the second metal layer is isolated from the inner metal layers on other core boards. When performing layer deviation detection on the m-th core board, an electrically connected first probe and second probe can be used. The second probe is inserted into the second detection hole corresponding to the m-th core board and contacts the second metal layer, so that the second probe is in conduction with the inner metal layer of the m-th core board; the first probe is inserted into the first detection hole and contacts the first metal layer. Since the radius of the first detection hole is smaller than the radius of the corresponding first isolation groove, if the layer deviation of the m-th core board is less than the difference between the radius of the first detection hole and the radius of the corresponding first isolation groove, the first detection hole will penetrate through the corresponding first isolation groove internally, and at this time, the first metal layer is isolated from the inner metal layer of the m-th core board, that is, the first probe is isolated from the inner metal layer of the m-th core board, and at this time, an open circuit is formed between the first probe and the second probe; if the layer deviation of the m-th core board is greater than the difference between the radius of the first detection hole and the radius of the corresponding first isolation groove, the first detection hole will at least partially penetrate through the inner metal layer outside the first isolation groove, and at this time, the first metal layer will be in contact conduction with the inner metal layer of the m-th core board, that is, the first probe will be in conduction with the inner metal layer of the m-th core board, and at this time, a short circuit or conduction loop is formed between the first probe and the second probe. It can be seen that in the layer deviation detection structure of the multi-layer printed circuit board according to the embodiment of the present invention, when performing layer deviation detection on the m-th core board, only need to insert the first probe into the first detection hole, insert the second probe into the second detection hole corresponding to the m-th core board, and by judging the electrical connection state between the first probe and the second probe, the layer deviation amount of the m-th core board can be judged. The operation is simple, and it is beneficial to quickly detect the layer deviation amounts of each layer of the multi-layer printed circuit board.

[0008] According to some embodiments of the present invention, in the first detection area, the number of the first detection points is at least two, and the first isolation groove is provided on the outer periphery of each of the first detection points; the radius of each of the first detection holes is smaller than the radius of the corresponding first isolation groove, and the difference between the radius of each of the first detection holes and the radius of the corresponding first isolation groove is different.

[0009] According to some embodiments of the present invention, the radii of all the first detection holes are the same, and in each of the first detection areas, the radii of any two of the first isolation grooves are different.

[0010] According to some embodiments of the present utility model, the difference between the radius of the first detection hole and the radius of the smallest first isolation groove is 0.13 mm.

[0011] According to some embodiments of the present utility model, the number of the first isolation grooves is four, and the differences between the radius of the first detection hole and the radii of the respective first isolation grooves are x1, x2, x3, and x4 respectively, where x1 = 0.13 mm, x2 = 0.15 mm, x3 = 0.175 mm, and x4 = 0.2 mm.

[0012] According to some embodiments of the present utility model, the diameters of the four first detection holes are all 1 mm, and the diameters of the four first isolation grooves are 1.26 mm, 1.3 mm, 1.35 mm, and 1.4 mm respectively.

[0013] According to some embodiments of the present utility model, in the outer metal layer, the number of the third isolation grooves is one, and all the first detection holes are located inside the same third isolation groove, or the number of the third isolation grooves is at least two, and at least one first detection hole is provided in each third isolation groove.

[0014] According to some embodiments of the present utility model, in the outer metal layer, the number of the fourth isolation grooves is one, and all the second detection holes are located inside the same fourth isolation groove, or the number of the fourth isolation grooves is at least two, and at least one second detection hole is provided in each fourth isolation groove.

[0015] According to some embodiments of the present utility model, in the second detection area, all the second detection points are arranged in sequence along the left - right direction of the core board, the m - th core board from top to bottom corresponds to the m - th second detection point from left to right. In the first or n - th core board, the number of the second isolation grooves is one, and the second detection point corresponding to the core board is located outside all the second isolation grooves, and the other second detection points are located inside the same second isolation groove; in the m - th core board, where n > 2, 1 < m < n, the number of the second isolation grooves is two, the m - th second detection point is located between the two second isolation grooves, all the second detection points on one side of the m - th second detection point are located in one of the second isolation grooves, and all the second detection points on the other side of the m - th second detection point are located in the other second isolation groove.

[0016] According to some embodiments of the present utility model, the distance a between the inner wall of each of the first detection holes and the edge of the corresponding third isolation groove is greater than 0.5 mm; and / or the distance b between the inner wall of each of the second detection holes and the edge of the corresponding second isolation groove is greater than 0.5 mm; and / or the distance c between the inner wall of each of the second detection holes and the edge of the corresponding fourth isolation groove is greater than 0.5 mm.

[0017] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present utility model will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, wherein:

[0019] Figure 1 Schematic diagram of the inner metal layer of the first core board of the embodiment of the present utility model;

[0020] Figure 2 Schematic diagram of the inner metal layer of the second core board of the embodiment of the present utility model;

[0021] Figure 3 Schematic diagram of the inner metal layer of the third core board of the embodiment of the present utility model;

[0022] Figure 4 Schematic diagram of the inner metal layer of the third core board of the embodiment of the present utility model;

[0023] Figure 5 Schematic diagram of the inner metal layer of the fifth core board of the embodiment of the present utility model;

[0024] Figure 6 Schematic diagram of the inner metal layer of the sixth core board of the embodiment of the present utility model;

[0025] Figure 7 Schematic diagram of the outer metal layer of the embodiment of the present utility model;

[0026] Figure 8 Schematic cross-sectional view of the layer deviation detection structure of the embodiment of the present utility model at the first detection area of the core board;

[0027] Figure 9 Schematic cross-sectional view of the layer deviation detection structure of the embodiment of the present utility model at the second detection area of the core board;

[0028] Figure 10 Schematic diagram of the first layer of the core board of the layer deviation detection structure of the embodiment of the present utility model without layer deviation;

[0029] Figure 11 Cross-sectional schematic view showing layer deviation of the first core board of the layer deviation detection structure of the utility model embodiment.

[0030] Reference numerals:

[0031] Core board 100, insulating layer 110, inner metal layer 120, first detection point 130, first isolation groove 131, second detection point 140, second isolation groove 141;

[0032] Outer metal layer 200, dielectric layer 210, third isolation groove 220, fourth isolation groove 230;

[0033] First detection hole 300, first metal layer 301, second detection hole 310, second metal layer 311. Detailed implementation manners

[0034] The embodiments of the present utility model will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation to the present utility model.

[0035] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model 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 thus should not be construed as a limitation to the present utility model.

[0036] In the description of the present utility model, the meaning of "several" is one or more, the meaning of "multiple" is two or more, "greater than", "less than", "exceeding", etc. are understood as not including the present number, and "above", "below", "within", etc. are understood as including the present number. If the first and second are described only for the purpose of distinguishing technical features, they should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or the sequence relationship of the indicated technical features.

[0037] In the description of the present utility model, unless otherwise clearly defined, terms such as "set", "installed", "connected", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present utility model in combination with the specific content of the technical solution.

[0038] Refer to Figures 1 to 11, an embodiment of the present utility model provides a layer deviation detection structure for a multi-layer printed circuit board. The layer deviation detection structure of the multi-layer printed circuit board includes n core boards 100 and two outer metal layers 200, where n > 1 and n is an integer. The core board 100 includes an insulating layer 110 and an inner metal layer 120 located on the surface of the insulating layer 110. Each inner metal layer 120 has a first detection area and a second detection area. The first detection area has at least one first detection point 130. A first isolation groove 131 is formed around the first detection point 130, and the first isolation groove 131 extends to the insulating layer 110. The second detection area has n second detection points 140, and the n second detection points 140 correspond to the n core boards 100 one by one. The second detection area is provided with a second isolation groove 141 extending to the insulating layer 110. In the m-th core board 100, 1 ≤ m ≤ n and m is an integer, the second detection point 140 corresponding to the m-th core board 100 is located outside the second isolation groove 141, and the other second detection points 140 are located inside the second isolation groove 141. The two outer metal layers 200 are correspondingly laminated on the opposite sides of the n core boards 100 to form a multi-layer board. A dielectric layer 210 is provided between the outer metal layer 200 and the adjacent core board 100. At least one outer metal layer 200 is provided with first detection holes 300 corresponding to all the first detection points 130 in the first detection area one by one. The first detection holes 300 penetrate through the multi-layer board, and the radius of the first detection holes 300 is smaller than the radius of the corresponding first isolation grooves 131. A first metal layer 301 extending to the two outer metal layers 200 is further provided on the inner wall of the first detection holes 300. Each outer metal layer 200 is further provided with a third isolation groove 220 extending to the corresponding dielectric layer 210, and the first detection holes 300 are located in the third isolation grooves 220. At least one outer metal layer 200 is provided with second detection holes 310 corresponding to all the second detection points 140 in the second detection area one by one. The second detection holes 310 penetrate through the multi-layer board, the second detection holes 310 penetrate through the corresponding second detection points 140 on each core board 100 and are located in the corresponding second isolation grooves 141. A second metal layer 311 extending to the two outer metal layers 200 is further provided on the inner wall of the second detection holes 310. Each outer metal layer 200 is further provided with a fourth isolation groove 230 extending to the corresponding dielectric layer 210, and the second detection holes 310 are located in the second isolation grooves 141.

[0039] By adopting the layer deviation detection structure of the multi-layer printed circuit board according to the embodiment of the present invention, in the m-th core board 100, where 1 ≤ m ≤ n and m is an integer, the second detection point 140 corresponding to the m-th core board 100 is located outside the second isolation groove 141, while on other core boards 100, the second detection point 140 corresponding to the m-th core board 100 is located inside the second isolation groove 141. Thus, the second detection hole 310 corresponding to the m-th core board 100 will penetrate through the inner metal layer 120 of the m-th core board 100 and through the second isolation groove 141 of other core boards 100. That is, in the second detection hole 310 corresponding to the m-th core board 100, the second metal layer 311 is in contact conduction with the inner metal layer 120 of the m-th core board 100, and the second metal layer 311 is isolated from the inner metal layer 120 on other core boards 100.

[0040] When performing layer deviation detection on the m-th core board 100, a first probe and a second probe that are electrically connected can be used. The second probe is inserted into the second detection hole 310 corresponding to the m-th core board 100 and contacts the second metal layer 311, so that the second probe is in conduction with the inner metal layer 120 of the m-th core board 100. The first probe is inserted into the first detection hole 300 and contacts the first metal layer 301. Since the radius of the first detection hole 300 is smaller than the radius of the corresponding first isolation groove 131; if the layer deviation of the m-th core board 100 is less than the difference between the radius of the first detection hole 300 and the radius of the corresponding first isolation groove 131, the first detection hole 300 will penetrate through the inside of the corresponding first isolation groove 131. At this time, since the first isolation groove 131 extends to the insulating layer 110 of the core board 100, the first metal layer 301 is isolated from the inner metal layer 120 of the m-th core board 100, that is, the first probe is isolated from the inner metal layer 120 of the m-th core board 100, and at this time, an open circuit is formed between the first probe and the second probe; if the layer deviation of the m-th core board 100 is greater than the difference between the radius of the first detection hole 300 and the radius of the corresponding first isolation groove 131, the first detection hole 300 will at least partially penetrate through the inner metal layer 120 outside the first isolation groove 131. At this time, the first metal layer 301 will be in contact conduction with the inner metal layer 120 of the m-th core board 100, that is, the first probe will be in conduction with the inner metal layer 120 of the m-th core board 100 through the first metal layer 301, and at this time, the first probe and the second probe form a short circuit or a conduction loop.

[0041] It can be seen that in the layer deviation detection structure of the multi-layer printed circuit board according to the embodiment of the present utility model, when detecting the layer deviation of the m-th core board 100, only need to insert the first probe into the first detection hole 300, and insert the second probe into the second detection hole 310 corresponding to the m-th core board 100. If an open circuit is formed between the first probe and the second probe, it means that the layer deviation amount of the m-th core board 100 is less than the difference between the radius of the first detection hole 300 and the radius of the corresponding first isolation groove 131. If a short circuit or conduction loop is formed between the first probe and the second probe, it means that the layer deviation of the m-th core board 100 is greater than the difference between the radius of the first detection hole 300 and the radius of the corresponding first isolation groove 131. That is, by judging the electrical connection state between the first probe and the second probe, the layer deviation amount of the m-th core board 100 can be judged. And when it is necessary to detect the layer deviation amounts of different core boards 100, only need to insert the second probe into different second detection holes 310. The operation is simple and is beneficial to quickly detecting the layer deviation amounts of each layer of the multi-layer printed circuit board.

[0042] For example, when detecting the layer deviation amount of the first core board 100, that is, when m = 1, refer to Figure 10 , if the layer deviation amount of the first core board 100 is not less than the difference between the radius of the first detection hole 300 and the radius of the corresponding first isolation groove 131, and the first detection hole 300 penetrates through the corresponding first isolation groove 131 internally. At this time, the first metal layer 301 is isolated from the inner metal layer 120 of the first core board 100, that is, the first probe is isolated from the inner metal layer 120 of the first core board 100. At this time, an open circuit is formed between the first probe and the second probe; refer to Figure 11 , if the layer deviation of the first core board 100 is greater than the difference between the radius of the first detection hole 300 and the radius of the corresponding first isolation groove 131, the first detection hole 300 will penetrate through at least part of the inner metal layer 120 outside the first isolation groove 131. At this time, the first metal layer 301 will be in contact and conduction with the inner metal layer 120 of the first core board 100, that is, the first probe will be in conduction with the inner metal layer 120 of the first core board 100 through the first metal layer 301. At this time, a short circuit or conduction loop is formed between the first probe and the second probe. Thus, by judging the electrical connection state between the first probe and the second probe, the layer deviation amount of the first core board 100 can be judged. The operation is simple and is beneficial to quickly detecting the layer deviation amounts of each layer of the multi-layer printed circuit board.

[0043] It can be understood that in the above structure, the first isolation groove 131 and the second isolation groove 141 both extend to the corresponding insulating layer 110, so that there is no conductive metal between the structure inside the isolation groove and the inner metal layer 120 outside the isolation groove, and thus the structure inside the isolation groove and the inner metal layer 120 outside the isolation groove are isolated from each other. Among them, the first isolation groove 131 and the second isolation groove 141 can be specifically formed by windowing during the production of the inner layer circuit. Similarly, the third isolation groove 220 and the fourth isolation groove 230 both extend to the corresponding dielectric layer 210, so that the structure located inside the isolation groove can be isolated from the outer metal layer 200 outside the isolation groove. Specifically, the first detection hole 300 is located inside the third isolation groove 220, so that the first metal layer 301 on the inner wall of the first detection hole 300 can be isolated from the outer metal layer 200. The second detection hole 310 is located inside the fourth isolation groove 230, so that the second metal layer 311 on the inner wall of the second detection hole 310 can be isolated from the outer metal layer 200. Thus, when performing layer deviation detection, both the first probe and the second probe can be isolated from the outer metal layer 200, avoiding the first probe and the second probe from directly forming a short circuit or a conduction loop due to contact with the outer metal layer 200, and further improving the accuracy of layer deviation detection. Among them, the third isolation groove 220 and the fourth isolation groove 230 can be specifically formed by windowing during the production of the outer layer circuit.

[0044] It can be understood that in the above structure, by providing the first metal layer 301 extending to the two outer metal layers 200 on the inner wall of the first detection hole 300, when inserting the first probe into the first detection hole 300 to determine whether it is conductive to the inner metal layer 120 of the mth layer core board 100, it is not necessary to extend the first probe to the depth where the mth layer core board 100 is located. It is only necessary to insert the first probe into the first detection hole 300 and contact the first metal layer 301, thus making the layer deviation detection simpler and more convenient. Similarly, by providing the second metal layer 311 extending to the two outer metal layers 200 on the inner wall of the second detection hole 310, when inserting the second probe into the second detection hole 310 corresponding to the mth layer to make the second probe conductive to the inner metal layer 120 of the mth layer core board 100, it is not necessary to extend the second probe to the depth where the mth layer core board 100 is located. It is only necessary to insert the second probe into the second detection hole 310 and contact the second metal layer 311, thus making the layer deviation detection simpler and more convenient.

[0045] It can be understood that at least one of the above-mentioned outer metal layers 200 is provided with a first detection hole 300, and the first detection hole 300 penetrates through the multi-layer board. Specifically, it means that the first detection hole 300 can be processed and extended from one of the outer metal layers 200 to another metal layer, or it can also be directly processed from two outer metal layers 200 to penetrate through the multi-layer board. The present utility model does not make specific limitations on this. Similarly, at least one of the above-mentioned outer metal layers 200 is provided with a second detection hole 310. Specifically, it means that the second detection hole 310 can be processed and extended from one of the outer metal layers 200 to another metal layer, or it can also be directly processed from two outer metal layers 200 to penetrate through the multi-layer board. The present utility model does not make specific limitations on this.

[0046] It can be understood that the above-mentioned core board 100 includes an insulating layer 110 and an inner metal layer 120 located on the surface of the insulating layer 110. Specifically, an inner metal layer 120 can be provided on one side surface of the insulating layer 110, or as Figures 1 to 11 shown, it can also be that inner metal layers 120 are provided on both side surfaces of the insulating layer 110. At this time, the first detection holes 300, the first isolation grooves 131, the second detection holes 310, and the second isolation grooves 141 on the two inner metal layers 120 are symmetrically arranged with respect to the insulating layer 110. The present utility model does not make specific limitations on the specific structure of the core board 100.

[0047] It can be understood that the inner metal layer 120, the outer metal layer 200, the first metal layer 301, and the second metal layer 311 can all be made of copper metal. Of course, in addition to this, aluminum or other conductive metals can also be used. The present utility model does not make specific limitations on this.

[0048] It can be understood that in some embodiments, in order to more conveniently judge the electrical connection state between the first probe and the second probe during layer deviation detection, a response device can be electrically connected between the first probe and the second probe. If the response device does not respond, it means that an open circuit is formed between the first probe and the second probe. If the response device responds, it means that a conduction loop is formed between the first probe and the second probe. Among them, the response device can specifically adopt a sound-emitting device such as a buzzer or a beeper, or the response device can also adopt an indicator light or other electronic components. The present utility model does not make specific limitations on this.

[0049] Referring to Figures 1 to 11 , in some embodiments, in the first detection area, the number of the first detection points 130 is at least two, and a first isolation groove 131 is provided on the outer periphery of each first detection point 130; the radius of each first detection hole 300 is smaller than the radius of the corresponding first isolation groove 131, and the difference between the radius of each first detection hole 300 and the radius of the corresponding first isolation groove 131 is different.

[0050] By adopting the above structure, the number of the first detection points 130 is at least two, and a first detection hole 300 is correspondingly formed at each first detection point 130. Since the difference between the radius of each first detection hole 300 and the radius of the corresponding first isolation groove 131 is different, when performing layer deviation detection on the m-th core board 100, where 1 ≤ m ≤ n and m is an integer, the second probe is inserted into the second detection hole 310 corresponding to the m-th core board 100 and contacts the second metal layer 311, and the first probe is inserted into different first detection holes 300 and contacts the corresponding first metal layer 301. Thus, the layer deviation range of the m-th core board 100 can be further determined, making the layer deviation detection more accurate.

[0051] Referring to Figures 1 to 11 , in some embodiments, the radii of all the first detection holes 300 are the same, and in each first detection area, the radii of any two first isolation grooves 131 are different.

[0052] By adopting the above structure, when processing, a plurality of first isolation grooves 131 with different radii are processed on each core board 100. After the core board 100 is laminated with the outer metal layer 200, a drill bit with the same size can be used when processing each first detection hole 300. Thus, there is no need to replace the tool during the processing, making the processing of the printed circuit board more convenient and efficient.

[0053] In some embodiments, the difference between the radius of the first detection hole 300 and the radius of the smallest first isolation groove 131 is 0.13 mm.

[0054] The layer deviation alignment requirement of the multilayer printed circuit board is usually within 0.125 mm. If the difference between the radius of the first detection hole 300 and the radius of the smallest first isolation groove 131 is set to 0.125 mm, when detecting the m-th core board 100, if the layer deviation of the m-th core board 100 is exactly 0.125 mm, the first metal layer 301 on the inner wall of the first detection hole 300 will be electrically connected to the inner metal layer 120 of the m-th core board 100, resulting in a short circuit or a conduction loop between the first probe and the second probe. Therefore, it is easy to determine that the layer deviation of the m-th core board 100 is greater than 0.125 mm, causing the circuit board to be misjudged as unqualified. Therefore, by setting the difference between the radius of the first detection hole 300 and the radius of the smallest first isolation groove 131 to 0.13 mm, that is, 0.005 mm larger than 0.125 mm, it is possible to avoid the formation of a short circuit or a conduction loop between the first probe and the second probe when the layer deviation of the core board 100 is exactly 0.125 mm, and further reduce the risk of misjudgment.

[0055] Referring to Figures 1 to 11, in some embodiments, the number of the first isolation grooves 131 is four, and the differences between the radius of the first detection holes 300 and the radii of the respective first isolation grooves 131 are x1, x2, x3, and x4 respectively, where x1 = 0.13 mm, x2 = 0.15 mm, x3 = 0.175 mm, and x4 = 0.2 mm.

[0056] By adopting the above structure, when performing layer deviation detection on the mth layer of core board 100, where 1 ≤ m ≤ n and m is an integer, insert the second probe into the corresponding second detection hole 310 so that the second probe is electrically connected to the inner metal layer 120 of the mth layer of core board 100, and insert the first probe into the first detection hole 300 with a difference of x1 = 0.13 mm. If an open circuit is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is less than 0.13 mm. If a short circuit or conduction loop is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is greater than 0.13 mm. At this time, the first probe can be inserted into the first detection hole 300 with a difference of x2 = 0.15 mm; if an open circuit is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is between 0.13 mm and 0.15 mm. If a short circuit or conduction loop is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is greater than 0.15 mm. At this time, the first probe can be inserted into the first detection hole 300 with a difference of x3 = 0.175 mm; if an open circuit is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is between 0.15 mm and 0.175 mm. If a short circuit or conduction loop is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is greater than 0.175 mm. At this time, the first probe can be inserted into the first detection hole 300 with a difference of x4 = 0.2 mm; if an open circuit is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is between 0.175 mm and 0.2 mm. If a short circuit or conduction loop is formed between the first probe and the second probe, it means that the layer deviation of the mth core board 100 is greater than 0.2 mm. Thus, the layer deviation range of the mth core board 100 can be judged more accurately.

[0057] Refer to Figures 1 to 11 , in some embodiments, the diameters of the four first detection holes 300 are all 1 mm, and the diameters of the four first isolation grooves 131 are 1.26 mm, 1.3 mm, 1.35 mm, and 1.4 mm respectively.

[0058] By adopting the above structure, it is convenient to open the first detection holes 300, and the differences between the radius of the first detection holes 300 and the radii of the respective first isolation grooves 131 are x1, x2, x3, and x4 respectively, where x1 = 0.13 mm, x2 = 0.15 mm, x3 = 0.175 mm, and x4 = 0.2 mm.

[0059] Referring to Figures 1 to 11 , in some embodiments, in the outer metal layer 200, the number of the third isolation grooves 220 is one, and all the first detection holes 300 are located inside the same third isolation groove 220.

[0060] By adopting the above structure, all the first detection holes 300 are located inside the same third isolation groove 220. Since the third isolation groove 220 extends to the corresponding dielectric layer 210, there is no conductive metal inside the third isolation groove 220, so that the first metal layers 301 on the inner walls of the respective first detection holes 300 are isolated from each other. In addition, by providing only one third isolation groove 220, the processing and opening of the third isolation groove 220 can be made more convenient and fast.

[0061] It can be understood that in addition to providing only one third isolation groove 220 and making all the first detection holes 300 located inside the same third isolation groove 220, in some embodiments, at least two third isolation grooves 220 can also be provided, and at least one first detection hole 300 is provided inside each third isolation groove 220. For example, a third isolation groove 220 can be correspondingly provided on the outer periphery of each first detection hole 300, and the present utility model does not make specific limitations thereto.

[0062] Referring to Figures 1 to 11 , in some embodiments, in the outer metal layer 200, the number of the fourth isolation grooves 230 is one, and all the second detection holes 310 are located inside the same fourth isolation groove 230.

[0063] By adopting the above structure, all the second detection holes 310 are located inside the same fourth isolation groove 230. Since the fourth isolation groove 230 extends to the corresponding dielectric layer 210, there is no conductive metal inside the fourth isolation groove 230, so that the second metal layers 311 on the inner walls of the respective second detection holes 310 are isolated from each other. In addition, by providing only one fourth isolation groove 230, the processing and opening of the fourth isolation groove 230 can be made more convenient and fast.

[0064] It can be understood that, in addition to only setting one fourth isolation groove 230 and making all the second detection holes 310 located inside the same fourth isolation groove 230, in some embodiments, at least two fourth isolation grooves 230 can also be set, and at least one second detection hole 310 is provided inside each fourth isolation groove 230. For example, a fourth isolation groove 230 can be correspondingly provided around each second detection hole 310, and the present utility model does not make specific limitations thereto.

[0065] Referring to Figures 1 to 11 , in some embodiments, in the second detection area, all the second detection points 140 are arranged in sequence along the left - right direction of the core board 100, the m - th core board 100 from top to bottom corresponds to the m - th second detection point 140 from left to right. In the 1st or n - th core board 100, the number of second isolation grooves 141 is one, and the second detection point 140 corresponding to the core board 100 is located outside all the second isolation grooves 141, and other second detection points 140 are located inside the same second isolation groove 141; in the m - th core board 100, where n>2, 1<m<n, the number of second isolation grooves 141 is two, the m - th second detection point 140 is located between the two second isolation grooves 141, all the second detection points 140 on one side of the m - th second detection point 140 are located in one of the second isolation grooves 141, and all the second detection points 140 on the other side of the m - th second detection point 140 are located in the other second isolation groove 141.

[0066] By adopting the above - mentioned structure, for the 1st and n - th core boards 100, only one second isolation groove 141 needs to be opened on the inner metal layer 120, and for the m - th core board 100, only two second isolation grooves 141 need to be opened, thereby further simplifying the processing procedure of the core board 100 and improving the processing efficiency of the multilayer printed circuit board.

[0067] For example, referring to Figures 1 to 11 , in some embodiments, n = 6, all the second detection points 140 are arranged in sequence along the left - right direction of the core board 100, and all the core boards 100 are in one - to - one correspondence with all the second detection points 140 in the order from left to right along the order from top to bottom. Referring to Figure 1 and Figure 6, for the first core board 100 and the sixth core board 100, the number of the second isolation grooves 141 is one. Specifically, in the first core board 100, the first second detection point 140 is outside the second isolation groove 141, and the other second detection points 140 are all inside the second isolation groove 141. In the sixth core board 100, the sixth detection point is outside the second isolation groove 141, and the other second detection points 140 are all inside the second isolation groove 141. For the second core board 100 to the fifth core board 100, the number of the second isolation grooves 141 is two. Specifically, in the second core board 100, the second second detection point 140 is between the two second isolation grooves 141, the first second detection point 140 is inside one of the second isolation grooves 141, and the third detection point to the sixth detection point are inside the other second isolation groove 141. In the third core board 100, the third second detection point 140 is between the two second isolation grooves 141, the first second detection point 140 and the second detection point are inside one of the second isolation grooves 141, and the fourth detection point to the sixth detection point are inside the other second isolation groove 141.

[0068] Referring to Figures 1 to 11 , in some embodiments, the distance a between the inner wall of each first detection hole 300 and the edge of the corresponding third isolation groove 220 is greater than 0.5 mm.

[0069] By adopting the above structure, the distance between the inner wall of the first detection hole 300 and the outer metal layer 200 outside the third isolation groove 220 can be fully guaranteed, and the situation that the first metal layer 301 on the inner wall of the first detection hole 300 is electrically connected to the outer metal layer 200 outside the third isolation groove 220 can be avoided.

[0070] It can be understood that the distance a between the inner wall of each first detection hole 300 and the edge of the corresponding third isolation groove 220 being greater than 0.5 mm specifically means that when the third isolation groove 220 is circular and coaxially arranged with the first detection hole 300, the distance a between the inner wall of the first detection hole 300 and the edge of the corresponding third isolation groove 220 is greater than 0.5 mm; when the third isolation groove 220 is non-circular or the third isolation groove 220 is not coaxially arranged with the first detection hole 300, the minimum distance between the inner wall of the first detection hole 300 and the edge of the corresponding third isolation groove 220 needs to be greater than 0.5 mm.

[0071] Referring to Figures 1 to 11 , in some embodiments, the distance b between the inner wall of each second detection hole 310 and the edge of the corresponding second isolation groove 141 is greater than 0.5 mm.

[0072] By adopting the above structure, the distance between the inner wall of the second detection hole 310 and the inner metal layer 120 outside the second isolation groove 141 can be fully ensured, avoiding direct contact between the second metal layer 311 on the inner wall of the second detection hole 310 and the inner metal layer 120 outside the second isolation groove 141, which may lead to inaccurate layer deviation detection.

[0073] It can be understood that the distance b between the inner wall of each of the above-mentioned second detection holes 310 and the edge of the corresponding second isolation groove 141 is greater than 0.5 mm. Specifically, when the second isolation groove 141 is circular and coaxially arranged with the second detection hole 310, the distance b between the inner wall of the second detection hole 310 and the edge of the corresponding second isolation groove 141 is greater than 0.5 mm; when the second isolation groove 141 is non-circular or the second isolation groove 141 is not coaxially arranged with the second detection hole 310, the minimum distance between the inner wall of the second detection hole 310 and the edge of the corresponding second isolation groove 141 needs to be greater than 0.5 mm.

[0074] Refer to Figures 1 to 11 , in some embodiments, the distance c between the inner wall of each second detection hole 310 and the edge of the corresponding fourth isolation groove 230 is greater than 0.5 mm.

[0075] By adopting the above structure, the distance between the inner wall of the second detection hole 310 and the outer metal layer 200 outside the fourth isolation groove 230 can be fully ensured, avoiding the situation of mutual conduction between the first metal layer 301 on the inner wall of the second detection hole 310 and the outer metal layer 200 outside the fourth isolation groove 230.

[0076] It can be understood that the distance a between the inner wall of each of the above-mentioned second detection holes 310 and the edge of the corresponding fourth isolation groove 230 is greater than 0.5 mm. Specifically, when the fourth isolation groove 230 is circular and coaxially arranged with the second detection hole 310, the distance a between the inner wall of the second detection hole 310 and the edge of the corresponding fourth isolation groove 230 is greater than 0.5 mm; when the fourth isolation groove 230 is non-circular or the fourth isolation groove 230 is not coaxially arranged with the second detection hole 310, the minimum distance between the inner wall of the second detection hole 310 and the edge of the corresponding fourth isolation groove 230 needs to be greater than 0.5 mm.

[0077] The above has described the embodiments of the present invention in detail with reference to the drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. Layer deviation detection structure for multi-layer printed circuit board, characterized in that, Comprising: n core plates (100), where n > 1 and n is an integer, and the core plate (100) includes an insulating layer (110) and an inner metal layer (120) located on the surface of the insulating layer (110). Each inner metal layer (120) has a first detection area and a second detection area. The first detection area has at least one first detection point (130). A first isolation groove (131) is formed on the outer periphery of the first detection point (130), and the first isolation groove (131) extends to the insulating layer (110). The second detection area has n second detection points (140), and the n second detection points (140) correspond to the n core plates (100) one by one. A second isolation groove (141) extending to the insulating layer (110) is formed in the second detection area. In the m-th core plate (100), 1 ≤ m ≤ n and m is an integer, the second detection point (140) corresponding to the m-th core plate (100) is located outside the second isolation groove (141), and the other second detection points (140) are located inside the second isolation groove (141). Two outer metal layers (200) are correspondingly laminated on the opposite sides of the n core plates (100) to form a multilayer board, and a dielectric layer (210) is provided between the outer metal layer (200) and the adjacent core plate (100). At least one of the outer metal layers (200) is provided with first detection holes (300) corresponding to all the first detection points (130) in the first detection area. The first detection holes (300) penetrate through the multilayer board, and the radius of the first detection holes (300) is smaller than the radius of the corresponding first isolation grooves (131). A first metal layer (301) extending to the two outer metal layers (200) is further provided on the inner wall of the first detection holes (300). Each outer metal layer (200) is further provided with a third isolation groove (220) extending to the corresponding dielectric layer (210), and the first detection holes (300) are located in the third isolation grooves (220). At least one of the outer metal layers (200) is provided with second detection holes (310) corresponding to all the second detection points (140) in the second detection area. The second detection holes (310) penetrate through the multilayer board, and the second detection holes (310) penetrate through the corresponding second detection points (140) on each core plate (100) and are located in the corresponding second isolation grooves (141). A second metal layer (311) extending to the two outer metal layers (200) is further provided on the inner wall of the second detection holes (310). Each outer metal layer (200) is further provided with a fourth isolation groove (230) extending to the corresponding dielectric layer (210), and the second detection holes (310) are located in the second isolation grooves (141).

2. The layer shift detection structure of the multilayer printed circuit board according to claim 1, wherein In the first detection area, the number of the first detection points (130) is at least two, and the first isolation groove (131) is formed on the outer periphery of each first detection point (130). The radius of each of the first detection holes (300) is smaller than the radius of the corresponding first isolation groove (131), and the difference between the radius of each of the first detection holes (300) and the radius of the corresponding first isolation groove (131) is different.

3. The layer shift detection structure of the multi-layer printed circuit board according to claim 2, characterized in that, The radii of all the first detection holes (300) are the same, and in each of the first detection areas, the radii of any two of the first isolation grooves (131) are different.

4. The layer deviation detection structure of the multilayer printed circuit board according to claim 3, wherein The difference between the radius of the first detection hole (300) and the radius of the smallest first isolation groove (131) is 0.13 mm.

5. The layer shift detection structure of the multi-layer printed circuit board according to claim 4, wherein, The number of the first isolation grooves (131) is four, and the differences between the radius of the first detection hole (300) and the radii of the respective first isolation grooves (131) are x1, x2, x3, x4, where x1 = 0.13 mm, x2 = 0.15 mm, x3 = 0.175 mm, and x4 = 0.2 mm.

6. The layer shift detection structure of the multi-layer printed circuit board according to claim 5, characterized in that, The diameters of the four first detection holes (300) are all 1 mm, and the diameters of the four first isolation grooves (131) are 1.26 mm, 1.3 mm, 1.35 mm, and 1.4 mm respectively.

7. The layer shift detection structure of the multi-layer printed circuit board according to claim 2, characterized in that, In the outer metal layer (200), the number of the third isolation grooves (220) is one, and all the first detection holes (300) are located inside the same third isolation groove (220), or the number of the third isolation grooves (220) is at least two, and at least one of the first detection holes (300) is provided in each of the third isolation grooves (220).

8. The layer shift detection structure of the multilayer printed circuit board according to claim 2, characterized in that, In the outer metal layer (200), the number of the fourth isolation grooves (230) is one, and all the second detection holes (310) are located inside the same fourth isolation groove (230), or the number of the fourth isolation grooves (230) is at least two, and at least one of the second detection holes (310) is provided in each of the fourth isolation grooves (230).

9. The layer deviation detection structure of the multi-layer printed circuit board according to claim 1, characterized in that In the second detection area, all the second detection points (140) are arranged in sequence in the left - right direction of the core board (100), and the m - th core board (100) from top to bottom corresponds to the m - th second detection point (140) from left to right. In the 1st or n - th core board (100), the number of the second isolation grooves (141) is one, and the second detection point (140) corresponding to the core board (100) is located outside all the second isolation grooves (141), and the other second detection points (140) are located inside the same second isolation groove (141). In the m-th core plate (100), where n > 2 and 1 < m < n, the number of the second isolation grooves (141) is two, the m-th second detection point (140) is located between the two second isolation grooves (141), all the second detection points (140) on one side of the m-th second detection point (140) are located in one of the second isolation grooves (141), and all the second detection points (140) on the other side of the m-th second detection point (140) are located in the other second isolation groove (141).

10. The layer shift detection structure of the multilayer printed circuit board according to any one of claims 1 to 9, characterized in that, The distance a between the inner wall of each first detection hole (300) and the edge of the corresponding third isolation groove (220) is greater than 0.5 mm; and / or the distance b between the inner wall of each second detection hole (310) and the edge of the corresponding second isolation groove (141) is greater than 0.5 mm; and / or the distance c between the inner wall of each second detection hole (310) and the edge of the corresponding fourth isolation groove (230) is greater than 0.5 mm.

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