Circuit board via hole detection method

Abstract

The invention discloses a circuit board via hole detection method, and the method comprises the steps: machining a detection hole at a position corresponding to a second machining position in a mechanical drilling process when at least one via hole is machined through employing the same drilling tool, thereby achieving the detection of at least one via hole. During detection, only the aperture of the detection hole in each processing area needs to be detected, and then whether the apertures of all the via holes in the processing area meet requirements can be screened and checked. Specifically, after all the via holes and the detection holes in the same processing area are processed, the drilling tool can be respectively drilled into the first detection bonding pad and the second detection bonding pad and is electrified, the sizes of the via holes can be detected by detecting the returned current, the multilayer board does not need to be transferred to a detection station in the whole detection process, and the detection efficiency is improved. Therefore, the production efficiency of the circuit board can be improved, and the production cost of the circuit board can be reduced.

Description

Technical Field

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

[0002] During the production and processing of circuit boards, certain detection methods are needed to detect the production quality of the circuit boards. For example, after multiple core boards are pressed together to form a multi-layer board, the multi-layer board needs to be mechanically drilled. In this process, since the drilling rig lacks the aperture detection function and the drill bit diameter may be incorrectly selected during drilling, it is easy to cause the multi-layer board to have problems such as large aperture, small aperture or missed drilling, which will cause the multi-layer board to be directly scrapped.

[0003] To this end, in the prior art, it is usually necessary to transfer the multilayer board to an inspection station after the multilayer board has been mechanically drilled, and to perform a manual pin gauge inspection or use a hole inspection machine to inspect the via hole diameters on the multilayer board to screen out unqualified multilayer boards. It takes a lot of time to transfer the multilayer board from the drilling station to the inspection station, and manual pin gauge inspection will greatly increase the labor cost of circuit board production. The use of a hole inspection machine will increase the equipment cost of the hole inspection machine. Therefore, the above method not only reduces the production efficiency of the circuit board, but also increases the production cost of the circuit board. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a circuit board via detection method, which can detect the via hole diameter of a multilayer board during mechanical drilling, which can not only improve the production efficiency of the circuit board, but also reduce the production cost of the circuit board.

[0005] According to an embodiment of the present invention, a circuit board via hole detection method comprises the following steps:

[0006] S1: cutting the material to obtain n core boards, where n≥1 and n is an integer, and each of the core boards comprises an insulating layer and metal layers located on two opposite sides of the insulating layer;

[0007] Among all the metal layers of the n core boards, at least one metal layer is a first metal layer, and at least one metal layer is a second metal layer.

[0008] The first metal layer and the second metal layer each have a tool hole position and m processing areas, m≥1 and m is an integer, each of the processing areas includes a first processing position and a second processing position, the first processing position is used to process the through hole to be drilled, and the second processing position is used to process the detection hole, the first metal layer also has a first detection position, and the second metal layer also has a second detection position, and the first detection position and the second detection position are arranged in a staggered manner;

[0009] S2: Inner layer circuit production,

[0010] A first circuit pattern is fabricated on the first metal layer, wherein the first circuit pattern comprises a first detection pad located at the first detection position, a first tool hole pad located at the tool hole position, and a first standard pad located at each of the second processing positions, wherein one end of each of the first standard pads is conductively connected to the first detection pad, and the other end is conductively connected to the first tool hole pad, and when m≥2, all the first standard pads are connected in parallel with each other;

[0011] A second circuit pattern is fabricated on the second metal layer, wherein the second circuit pattern comprises a second detection pad located at the second detection position, a second tool hole pad located at the tool hole position, and a second standard pad located at each of the second processing positions, wherein one end of each of the second standard pads is connected to the second detection pad and the other end is connected to the second tool hole pad, and when m≥2, all the second standard pads are connected in series in sequence;

[0012] Wherein, in the same processing area, the diameter of the first standard pad is d1, the diameter of the second standard pad is d2, the preset aperture of the through hole to be drilled is d0, and d1<d0<d2;

[0013] S3: Pressing the plates, placing n core plates between two third metal layers, and pressing them together to form a multilayer plate;

[0014] S4: Mechanical drilling, including:

[0015] S4.1: Install a conductive member on the multilayer board, wherein the conductive member penetrates the multilayer board and is disposed on the first tool hole pad and the second tool hole pad, and the two third metal layers are spaced apart from the conductive member, and the conductive member is grounded;

[0016] S4.2: Processing a via hole group corresponding to the m processing areas on the multilayer board, wherein the via hole group passes through the multilayer board, wherein in the same processing area, the via hole group includes at least one via hole and one detection hole, all the via holes pass through the first processing position, the detection hole passes through the second processing position, and the detection hole and all the via holes are processed by the same drill, and the actual aperture of the via hole is D,

[0017] S4.3: Drilling a drill into the multilayer board from top to bottom and penetrating the first detection pad, passing a current with a current value of A1 through the drill and detecting the returned current signal, if the detected current value a1=0, it is determined that all the vias in the m via groups are D>d1, and meet the preset aperture requirement of d0>d1; if the detected current value a1=A1, it is determined that the vias in at least one of the m via groups are missed or D<d1, and do not meet the preset aperture requirement of d0>d1;

[0018] A drill is drilled into the multilayer board from top to bottom and penetrates the second detection pad. A current with a current value of A2 is passed through the drill and the returned current signal is detected. If the detected current value a2=0, it is determined that at least one of the m via groups has D>d2, which does not meet the preset aperture requirement of d0<d2. If the detected current value a2=A2, it is determined that all the vias in the m via groups have D<d2, which meet the preset aperture requirement of d0<d2.

[0019] The circuit board via detection method according to the embodiment of the present invention has at least the following beneficial effects:

[0020] By adopting the circuit board via hole detection method of the embodiment of the present invention, since the preset aperture requirement of the via hole is d1<d0<d2 in the same processing area, therefore, it is only necessary to process at least one via hole by the same drill bit during the mechanical drilling process, and to process a detection hole at the position corresponding to the second processing position. When all the via holes and the detection holes are processed, the drill bit is drilled into the first detection pad and a current with a current value of A1 is passed. Since in the first circuit pattern, one end of the first standard pad is connected to the first tool pad and is grounded through the conductive member, and the other end is connected to the first detection pad. The pads are conductive. If in each processing area, all the vias meet the requirement of d0>d1, that is, the actual aperture of the via is D>d1, then the via will remove the corresponding first standard pad during the processing, resulting in a short circuit in the first circuit pattern. At this time, the returned current signal a1=0; if in one of the processing areas, there is at least one via that does not meet the requirement of d0>d1, that is, the actual aperture of the via is D<d1, then the via will penetrate the first standard pad during the processing, and the first circuit pattern is still in a conductive state. At this time, the returned current signal a1=A1. A drill is drilled into the second detection pad and a current with a current value of A2 is passed. Since in the second circuit pattern, one end of the second standard pad is connected to the second tool pad and grounded through the conductive member, and the other end is connected to the second detection pad, if in each processing area, all vias meet the requirement of d0<d2, that is, the actual aperture of the via D<d2, then the via will pass through the second standard pad during the processing, and the second circuit pattern will still be in the on state. At this time, the returned current signal a2=A2; if in one of the processing areas, at least one via does not meet the requirement of d0<d2, that is, the actual aperture of the via D>d2, then the via will remove the second standard pad during the processing, resulting in a short circuit in the second circuit pattern, and the returned current signal a2=0.

[0021] Therefore, in the circuit board via detection method of the embodiment of the present invention, the drill can be drilled into the detection pad and current can be passed during the mechanical drilling process. The size of the via can be detected by detecting the return current. There is no need to move the multilayer board to the detection station, and there is no need to increase labor costs and equipment investment costs. Therefore, not only the production efficiency of the circuit board can be improved, but also the production cost of the circuit board can be reduced.

[0022] According to some embodiments of the present invention, in each of the processing areas, d2-d1=0.05 mm.

[0023] According to some embodiments of the present invention, when n≥2, the number of the first metal layer is 1, the number of the second metal layer is also 1, the first metal layer is located on one of the core boards, and the second metal layer is located on another core board.

[0024] According to some embodiments of the present invention, step S3 further comprises laser drilling, where a tool hole is formed at a position of each core plate corresponding to the tool hole position, wherein the tool hole located at the first metal layer passes through the first tool hole pad, and the tool hole located at the second metal layer passes through the second tool hole pad;

[0025] In step S41, the conductive member is installed in all the tool holes.

[0026] According to some embodiments of the present invention, in step S4.1, before installing the conductive member, an isolation groove is opened on the outer surfaces of the two third metal layers, and the isolation groove is arranged around the periphery of the tool hole.

[0027] According to some embodiments of the present invention, in step S3,

[0028] When n=1, the core plate is placed between the two third metal layers for lamination, wherein a connection layer is sandwiched between the two third metal layers and the core plate;

[0029] When n≥2, all the core boards are stacked in sequence between two of the third metal layers and then pressed together, wherein a connecting layer is sandwiched between each two adjacent core boards and between two of the third metal layers and adjacent core boards.

[0030] According to some embodiments of the present invention, in step S4.1, the conductive member is a metal pin.

[0031] According to some embodiments of the present invention, the step S3 and the step S4.2 further include stacking the boards, stacking the bottom board, the multilayer board, and the protection board in sequence, wherein the protection board is spaced from the periphery of the tool hole.

[0032] According to some embodiments of the present invention, the protection plate is provided with a clearance groove corresponding to the tool hole, the tool hole is located in the clearance groove, and the periphery of the tool hole and the inner wall of the clearance groove are spaced apart.

[0033] According to some embodiments of the present invention, the protection plate is an aluminum plate.

[0034] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0036] Figure 1This is a schematic diagram of the first copper layer when m=5 in an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the second copper layer when m=5 in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the first copper layer when m=1 in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the second copper layer when m=1 in an embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of the first copper layer when m=2 in an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the second copper layer when m=2 in an embodiment of the present invention;

[0042] Figure 7 This is a schematic diagram of the first copper layer when m=3 in an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the second copper layer when m=3 in an embodiment of the present invention;

[0044] Fig. 9 Schematic diagram of the third copper layer according to an embodiment of the present invention.

[0045] Reference numerals:

[0046] A first metal layer 100, a first detection pad 110, a first tool hole pad 120, and a first standard pad 130;

[0047] A second metal layer 200, a second detection pad 210, a second tool hole pad 220, and a second standard pad 230;

[0048] A third metal layer 300 and an isolation trench 310;

[0049] Tool hole 400;

[0050] Processing area 500 , first processing position 510 , second processing position 520 , tool hole position 530 , first detection position 540 , second detection position 550 . DETAILED DESCRIPTION

[0051] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0052] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0053] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0054] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0055] Reference Figures 1 to 9 An embodiment of the present invention provides a circuit board via detection method, comprising the following steps:

[0056] S1: cutting the material to obtain n core boards, where n≥1 and n is an integer, each core board includes an insulating layer and metal layers located on opposite sides of the insulating layer, wherein the insulating layer may be a prepreg layer, and the metal layer may be a copper layer. In this case, the core board is a double-sided copper-clad board. In addition, the metal layer may also be an aluminum layer or other conductive layer, which is not specifically limited in the present invention;

[0057] Among all the metal layers of the n core boards, at least one metal layer is a first metal layer 100, and at least one metal layer is a second metal layer 200.

[0058] The first metal layer 100 and the second metal layer 200 each have a tool hole position 530 and m processing areas 500, m ≥ 1 and m is an integer, each processing area 500 includes a first processing position 510 and a second processing position 520, the first processing position 510 is used to process the hole to be drilled, and the second processing position 520 is used to process the detection hole, the first metal layer 100 also has a first detection position 540, and the second metal layer 200 also has a second detection position 550, the first detection position 540 and the second detection position 550 are staggered, that is, when the first metal layer 100 and the second metal layer 200 are superimposed, the projection of the first detection position 540 in the core plate thickness direction and the projection of the second detection position 550 in the core plate thickness direction are arranged at intervals;

[0059] S2: Inner layer circuit production,

[0060] A first circuit pattern is fabricated on the first metal layer 100, wherein the first circuit pattern includes a first detection pad 110 located at the first detection position 540, a first tool hole pad 120 located at the tool hole position 530, and a first standard pad 130 located at each second processing position 520, wherein one end of each first standard pad 130 is connected to the first detection pad 110, and the other end is connected to the first tool hole pad 120, and when m≥2, all first standard pads 130 are connected in parallel to each other, that is, all first standard pads 130 are connected in parallel between the first detection pad 110 and the first tool hole pad 120;

[0061] A second circuit pattern is fabricated on the second metal layer 200, wherein the second circuit pattern includes a second detection pad 210 located at the second detection position 550, a second tool hole pad 220 located at the tool hole position 530, and a second standard pad 230 located at each second processing position 520, wherein one end of each second standard pad 230 is connected to the second detection pad 210 and the other end is connected to the second tool hole pad 220, and when m≥2, all the second standard pads 230 are connected in series in sequence, that is, all the second standard pads 230 are connected in series in sequence between the second detection pad 210 and the second tool hole pad 220;

[0062] Among them, in the same processing area 500, the diameter of the first standard pad 130 is d1, the diameter of the second standard pad 230 is d2, the preset aperture of the via hole to be drilled is d0, d1<d0<d2, that is, the aperture requirement of the via hole to be drilled is d1<d0<d2;

[0063] S3: Pressing the boards, placing n core boards between two third metal layers 300, and pressing them together to form a multilayer board;

[0064] S4: Mechanical drilling, including:

[0065] S4.1: Install a conductive member on the multilayer board, the conductive member penetrates the multilayer board and is arranged on the first tool hole pad 120 and the second tool hole pad 220, and the conductive member is grounded, wherein the two third metal layers 300 are arranged at intervals from the conductive member, thereby avoiding contact and conduction between the conductive member and the third metal layer 300;

[0066] S4.2: Processing via groups corresponding to m processing areas 500 on the multilayer board, the via group runs through the multilayer board, wherein in the same processing area 500, the via group includes at least one via and one detection hole, all vias run through the first processing position 510, the detection hole runs through the second processing position 520, and the detection hole and all vias are processed by the same drill, and the actual aperture of the via is D,

[0067] S4.3: Drilling a drill into the multilayer board from top to bottom and penetrating the first detection pad 110, passing a current with a current value of A1 through the drill and detecting the returned current signal, if the detected current value a1=0, it is determined that all vias in the m via groups are D>d1, which meets the preset aperture requirement of d0>d1; if the detected current value a1=A1, it is determined that at least one via in the m via groups is missed or D<d1, which does not meet the preset aperture requirement of d0>d1;

[0068] A drill is drilled into the multilayer board from top to bottom and penetrates the second detection pad 210. A current with a current value of A2 is passed through the drill and the returned current signal is detected. If the detected current value a2=0, it is determined that at least one via in the m via groups has D>d2, which does not meet the preset aperture requirement of d0<d2. If the detected current value a2=A2, it is determined that all the vias in the m via groups have D<d2, which meet the preset aperture requirement of d0<d2.

[0069] By adopting the circuit board via detection method of the embodiment of the present invention, since the preset aperture requirement of the via in the same processing area 500 is d1<d0<d2, it is only necessary to process an inspection hole at the position corresponding to the second processing position 520 each time the same drill is used to process at least one via during the mechanical drilling process. Therefore, during the detection, it is only necessary to check the aperture of the inspection hole in each processing area 500 to screen and check whether the apertures of all the vias in the processing area 500 meet the requirements. Specifically, when all vias and detection holes in the same processing area 500 are processed, the drill is drilled into the first detection pad 110 and a current with a current value of A1 is passed. Since in the first circuit pattern, one end of the first standard pad 130 is connected to the first tool pad and grounded through the conductive part, and the other end is connected to the first detection pad 110, if in each processing area 500, all vias meet the requirement of d0>d1, that is, the actual aperture of the via D>d1, then the corresponding first standard pad 130 will be removed during the processing of the via, resulting in a short circuit in the first circuit pattern, and the returned current signal a1=0 at this time; if in one of the processing areas 500, there is at least one via that does not meet the requirement of d0>d1, that is, the actual aperture of the via D<d1, then the via will pass through the first standard pad 130 during the processing, and the first circuit pattern is still in a conductive state, and the returned current signal a1=A1 at this time. A drill is drilled into the second detection pad 210 and a current with a current value of A2 is passed. Since in the second circuit pattern, one end of the second standard pad 230 is connected to the second tool pad and grounded through the conductive member, and the other end is connected to the second detection pad 210, if in each processing area 500, all vias meet the requirement of d0<d2, that is, the actual aperture of the via D<d2, then the via will pass through the second standard pad 230 during the processing, and the second circuit pattern is still in the on state. At this time, the returned current signal a2=A2; if in one of the processing areas 500, at least one via does not meet the requirement of d0<d2, that is, the actual aperture of the via D>d2, then the via will remove the second standard pad 230 during the processing, resulting in a short circuit in the second circuit pattern, and the returned current signal a2=0.

[0070] As can be seen from the above, in the circuit board via detection method of the embodiment of the present invention, the drill can be respectively drilled into the first detection pad 110 and the second detection pad 210 during the mechanical drilling process and current can be passed through. The size of the via can be detected by detecting the return current. Specifically, when the drill drills into the first detection pad 110 and current A1 is passed through, if the detection current value a1=0, it is determined that all the vias in the m via groups are D>d1, which meets the preset aperture requirement of d0>d1; if the detection current If the value a1=A1, it is determined that at least one via in the m via groups has a missing hole or D<d1, which does not meet the preset aperture requirement of d0>d1; when the drill drills into the second detection pad 210 and passes the current A2, if the detection current value a2=0, it is determined that at least one via in the m via groups has D>d2, which does not meet the preset aperture requirement of d0<d2; if the detection current value a2=A2, it is determined that all the vias in the m via groups have D<d2, which meet the preset aperture requirement of d0<d2. When a1=0 and a2=A2, it means that the via meets the preset aperture requirements of d0>d1 and d0<d2 at the same time, which means that the multilayer circuit board is qualified. It can be seen that during the entire inspection process, there is no need to transfer the multilayer board to the inspection station, nor is there any need to increase labor costs and equipment investment costs. After mechanical drilling, the vias of the multilayer board can be inspected directly at the drilling station, which can not only improve the production efficiency of the circuit board, but also reduce the production cost of the circuit board.

[0071] It can be understood that when current is passed through the drill and the returned current signal is detected, the drilling equipment can be based on the current to the drill, and when the returned current signal is detected, an ammeter can be installed on the drilling equipment or a current detection circuit can be set, and the present invention does not make specific limitations on this.

[0072] Reference Figure 3 and Figure 4 In some embodiments, m=1, that is, the first metal layer 100 and the second metal layer 200 both have a tool hole position 530 and a processing area 500, the processing area 500 includes a first processing position 510 and a second processing position 520, the first metal layer 100 also has a first detection position 540, and the second metal layer 200 also has a second detection position 550, and the first detection position 540 and the second detection position 550 are staggered.

[0073] When making the inner layer circuit in step S2, a first circuit pattern is made in the first metal layer 100, and the first circuit pattern includes a first detection pad 110 located at the first detection position 540, a first tool hole pad 120 located at the tool hole position 530, and a first standard pad 130 located at the second processing position 520, one end of the first standard pad 130 is conductively connected to the first detection pad 110, and the other end is conductively connected to the first tool hole pad 120; a second circuit pattern is made in the second metal layer 200, and the second circuit pattern includes a second detection pad 210 located at the second detection position 550, a second tool hole pad 220 located at the tool hole position 530, and a second standard pad 230 located at the second processing position 520, one end of the second standard pad 230 is conductively connected to the second detection pad 210, and the other end is conductively connected to the second tool hole pad 220. The diameter of the first standard pad 130 is d1, the diameter of the second standard pad 230 is d2, the preset hole diameter of the through hole to be drilled is d0, and d1<d0<d2.

[0074] When mechanical drilling is performed in step S4.2, a via group corresponding to the processing area 500 is processed on the multilayer board, and the via group includes at least one via and one detection hole, wherein all the vias are located at the first processing position 510, and the detection holes are located at the second processing position 520. All the vias and the detection holes are processed by the same drill, so that the actual aperture of the vias and the detection holes is D, and then the detection process in step S4.3 is carried out.

[0075] Reference Figure 5 and Figure 6 In some embodiments, m=2, that is, the first metal layer 100 and the second metal layer 200 each have a tool hole 530 and two processing areas 500, the two processing areas 500 are arranged at intervals, each processing area 500 includes a first processing position 510 and a second processing position 520, the first metal layer 100 also has a first detection position 540, the second metal layer 200 also has a second detection position 550, and the first detection position 540 and the second detection position 550 are staggered.

[0076] When making the inner layer circuit in step S2, a first circuit pattern is made in the first metal layer 100, the first circuit pattern includes a first detection pad 110 located at the first detection position 540, a first tool hole pad 120 located at the tool hole position 530, and a first standard pad 130 located at two second processing positions 520, and the two first standard pads 130 are connected in parallel between the first detection pad 110 and the first tool hole pad 120; a second circuit pattern is made in the second metal layer 200, the second circuit pattern includes a second detection pad 210 located at the second detection position 550, a second tool hole pad 220 located at the tool hole position 530, and a second standard pad 230 located at two second processing positions 520, and the two second standard pads 230 are connected in series between the second detection pad 210 and the second tool hole pad 220. Among them, the diameter of the first standard pad 130 is d1, the diameter of the second standard pad 230 is d2, and the preset aperture of the through hole to be drilled is d0, d1<d0<d2.

[0077] When mechanical drilling is performed in step S4.2, two via groups corresponding to the two processing areas 500 are processed on the multilayer board. In each processing area 500, the via group includes at least one via and one detection hole, wherein all vias are located in the first processing position 510 and the detection holes are located in the second processing position 520. All vias and detection holes are processed by the same drill, so that the actual aperture of the vias and the detection holes is D, and then the detection process in step S4.3 is carried out.

[0078] It is understandable that two different drills can be used to process the via groups in the two processing areas 500, or the same drill can be used, and the present invention does not make specific limitations on this. Similarly, the sizes of the drills used to process the via groups in the two processing areas 500 can be the same or different, that is, the actual diameters of the vias in the two processing areas 500 can be equal or different, and the present invention does not make specific limitations on this.

[0079] Reference Figure 7 and Figure 8 In some embodiments, m=3, that is, the first metal layer 100 and the second metal layer 200 each have a tool hole 530 and three processing areas 500, and two adjacent processing areas 500 are arranged at intervals, and each processing area 500 includes a first processing position 510 and a second processing position 520. The first metal layer 100 also has a first detection position 540, and the second metal layer 200 also has a second detection position 550. The first detection position 540 and the second detection position 550 are staggered.

[0080] When making the inner layer circuit in step S2, a first circuit pattern is made in the first metal layer 100, the first circuit pattern includes a first detection pad 110 located at the first detection position 540, a first tool hole pad 120 located at the tool hole position 530, and a first standard pad 130 located at three second processing positions 520, and the three first standard pads 130 are connected in parallel between the first detection pad 110 and the first tool hole pad 120; a second circuit pattern is made in the second metal layer 200, the second circuit pattern includes a second detection pad 210 located at the second detection position 550, a second tool hole pad 220 located at the tool hole position 530, and a second standard pad 230 located at three second processing positions 520, and the three second standard pads 230 are connected in series between the second detection pad 210 and the second tool hole pad 220. Among them, the diameter of the first standard pad 130 is d1, the diameter of the second standard pad 230 is d2, and the preset aperture of the through hole to be drilled is d0, d1<d0<d2.

[0081] When mechanical drilling is performed in step S4.2, three via groups corresponding to the three processing areas 500 are processed on the multilayer board. In each processing area 500, the via group includes at least one via and one detection hole, wherein all vias are located at the first processing position 510 and the detection holes are located at the second processing position 520. All vias and detection holes are processed by the same drill, so that the actual aperture of the vias and the detection holes is D, and then the detection process in step S4.3 is carried out.

[0082] In some embodiments, within each processing area 500, d2-d1=0.05 mm.

[0083] By adopting the above method, the processing tolerance of the vias in each processing area 500 is 0.05mm. Therefore, the circuit board via detection method of the present application can screen out the circuit boards whose vias in each processing area 500 meet the requirements of d1<D<d2, which is beneficial to improve the via processing accuracy on the circuit board.

[0084] In some embodiments, when n≥2, the number of the first metal layer 100 is 1, the number of the second metal layer 200 is also 1, the first metal layer 100 is located on one of the core boards, and the second metal layer 200 is located on the other core board.

[0085] By adopting the above method, the first metal layer 100 and the second metal layer 200 are located on two core boards respectively, so that when making the inner layer circuit, the first metal layer 100 and the second metal layer 200 can be processed at the same time, so that the first circuit pattern and the second circuit pattern are made at the same time, which is conducive to improving the processing efficiency of the circuit board.

[0086] Reference Figures 1 to 9In some embodiments, step S3 further includes laser drilling, where a tool hole 400 is formed at a position of each core board corresponding to the tool hole position 530, wherein the tool hole 400 located at the first metal layer 100 penetrates the first tool hole pad 120, and the tool hole 400 located at the second metal layer 200 penetrates the second tool hole pad 220;

[0087] In step S41 , the conductive members are installed in all the tool holes 400 .

[0088] By adopting the above method, a tool hole 400 is opened at a position of each core plate corresponding to the tool hole position 530 . The arrangement of the tool hole 400 can facilitate the installation of the conductive member.

[0089] Reference Fig. 9 In some embodiments, in step S4.1, before installing the conductive member, an isolation groove 310 is opened on the outer surface of the two third metal layers 300, and the isolation groove 310 is arranged around the periphery of the tool hole 400.

[0090] By adopting the above method and opening the isolation grooves 310 on the outer surfaces of the two third metal layers 300 , it is possible to effectively prevent the conductive member from contacting and conducting with the third metal layer 300 after being installed in the tool hole 400 .

[0091] It is understandable that the isolation groove 310 may be a circular groove disposed around the periphery of the tool hole 400 , or may be an annular groove disposed around the periphery of the tool hole 400 , and the present invention does not make any specific limitation on this.

[0092] In some embodiments, in step S3, when n=1, the core board is placed between two third metal layers 300 for lamination, wherein a connection layer is sandwiched between the two metal layers and the core board. When n≥2, all core boards are sequentially stacked between two third metal layers 300 and then lamination is performed, wherein a connection layer is sandwiched between each two adjacent core boards and between the two third metal layers 300 and the adjacent core boards.

[0093] By adopting the above method, the connection layer can be provided to tightly connect the two adjacent core boards and the third metal layer 300 with the core board after lamination, so that the structure of the multilayer board is more firm and stable. The connection layer can be a prepreg layer.

[0094] In some embodiments, in step S4.1, the conductive member is a metal pin.

[0095] By adopting the above method, the conductive part is set as a metal pin, which can not only facilitate contact and conduction with the first tool hole pad 120 and the second tool hole pad 220 and grounding, but also facilitate fixing the multilayer board during the mechanical drilling process. The structure is simple, the materials are easy to obtain, and the operation is convenient.

[0096] In some embodiments, the step between step S3 and step S4.2 further includes stacking the plates, wherein the bottom plate, the multilayer plate, and the protection plate are stacked in sequence, wherein the protection plate is spaced from the periphery of the tool hole 400 .

[0097] By adopting the above method, it is necessary to stack the plates before mechanical drilling. When stacking the plates, the bottom plate, the multilayer plate, and the protective plate are stacked in sequence, which can facilitate the subsequent mechanical drilling. During the mechanical drilling process, the cutting force will cause the multilayer plate to vibrate slightly, and this vibration will affect the drilling accuracy. The protective plate has a certain weight and strength, which can withstand the vibration caused by the cutting force, which can not only make the drilling process more stable, thereby improving the processing efficiency, but also enhance the stability of the drilling and improve the drilling accuracy. . In addition, during the mechanical drilling process, cutting fluid is usually required to cool the cutting tool and the workpiece and help remove the chips. If there is no protection of the protective plate, the cutting fluid is easy to flow out from the drilling position during the drilling process, resulting in a very untidy processing environment and may pollute the workbench, the environment, etc. The protective plate can intercept the cutting fluid to prevent it from overflowing, keep the processing environment clean, and extend the service life of the equipment. In addition, by arranging the protective plate and the periphery of the tool hole 400 at intervals, it is possible to prevent the protective plate and the conductive member in the tool hole 400 from contacting and conducting with each other.

[0098] In some embodiments, the protection plate is provided with a clearance groove corresponding to the tool hole 400, the tool hole 530 is located in the clearance groove, and the periphery of the tool hole 400 and the inner wall of the clearance groove are arranged at intervals.

[0099] By adopting the above method, the setting of the give way groove can effectively isolate the tool hole 400 from the protection plate, so that the conductive parts in the tool hole 400 can be isolated from the protection plate, which is beneficial to prevent the conductive parts and the protection plate from contacting and conducting with each other, affecting the accuracy of subsequent via detection.

[0100] It can be understood that in order to prevent the conductive part and the protective plate from contacting and conducting with each other, in addition to opening an isolation groove 310 on the protective plate, a tool hole 400 can also be opened at the edge of the multilayer board, and the protective plate can be stacked on one side of the tool hole 400 when stacking the boards, thereby isolating the tool hole 400 from the protective plate.

[0101] In some embodiments, the protection plate is specifically an aluminum plate.

[0102] By adopting the above method, the aluminum sheet has strong mechanical strength and thermal conductivity, thereby enhancing the mechanical strength and thermal conductivity of the drilling location, and then facilitating heat dissipation of the multilayer board during the drilling process, thereby improving the reliability and stability of the circuit board.

[0103] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A circuit board via detection method, characterized in that: The following steps are involved: S1: cutting the material to obtain n core boards, where n≥1 and n is an integer, and each of the core boards comprises an insulating layer and metal layers located on two opposite sides of the insulating layer; Among all the metal layers of the n core boards, at least one metal layer is a first metal layer (100), and at least one metal layer is a second metal layer (200). The first metal layer (100) and the second metal layer (200) each have a tool hole position (530) and m processing areas (500), m≥1 and m is an integer, each processing area (500) comprises a first processing position (510) and a second processing position (520), the first processing position (510) is used to process a hole to be drilled, and the second processing position (520) is used to process a detection hole, the first metal layer (100) also has a first detection position (540), and the second metal layer (200) also has a second detection position (550), and the first detection position (540) and the second detection position (550) are arranged in a staggered manner; S2: Inner layer circuit production, A first circuit pattern is fabricated on the first metal layer (100), the first circuit pattern comprising a first detection pad (110) located at the first detection position (540), a first tool hole pad (120) located at the tool hole position (530), and a first standard pad (130) located at each of the second processing positions (520), one end of each of the first standard pads (130) being conductively connected to the first detection pad (110) and the other end being conductively connected to the first tool hole pad (120), and when m≥2, all the first standard pads (130) are connected in parallel with each other; A second circuit pattern is fabricated on the second metal layer (200), wherein the second circuit pattern comprises a second detection pad (210) located at the second detection position (550), a second tool hole pad (220) located at the tool hole position (530), and a second standard pad (230) located at each of the second processing positions (520), wherein one end of each of the second standard pads (230) is conductively connected to the second detection pad (210) and the other end is conductively connected to the second tool hole pad (220), and when m≥2, all the second standard pads (230) are sequentially connected in series; Wherein, in the same processing area (500), the diameter of the first standard pad (130) is d1, the diameter of the second standard pad (230) is d2, the preset hole diameter of the hole to be drilled is d0, and d1<d0<d2; S3: Pressing the plates, placing n core plates between two third metal layers (300) and pressing them together to form a multilayer plate; S4: Mechanical drilling, including: S4.1: Installing a conductive member on the multilayer board, wherein the conductive member penetrates the multilayer board and is disposed on the first tool hole pad (120) and the second tool hole pad (220), and the two third metal layers (300) are arranged at intervals from the conductive member, and the conductive member is grounded; S4.2: Processing a via hole group corresponding to the m processing areas (500) on the multilayer board, wherein the via hole group passes through the multilayer board, wherein within the same processing area (500), the via hole group includes at least one via hole and one detection hole, all the via holes pass through the first processing position (510), the detection hole passes through the second processing position (520), and the detection hole and all the via holes are processed by the same drill, and the actual hole diameter of the via hole is D, S4.3: Drilling a drill into the multilayer board from top to bottom and penetrating the first detection pad (110), passing a current with a current value of A1 through the drill and detecting the returned current signal; if the detected current value a1=0, it is determined that all the via holes in the m via hole groups are D>d1, and meet the preset aperture requirement of d0>d1; if the detected current value a1=A1, it is determined that the via holes in at least one of the m via hole groups are missed or D<d1, and do not meet the preset aperture requirement of d0>d1; A drill is drilled into the multilayer board from top to bottom and penetrates the second detection pad (210), a current with a current value of A2 is passed through the drill and the returned current signal is detected. If the detected current value a2=0, it is determined that at least one of the m via holes in the via hole group has D>d2 and does not meet the preset aperture requirement of d0<d2. If the detected current value a2=A2, it is determined that all of the via holes in the m via hole groups have D<d2 and meet the preset aperture requirement of d0<d2.

2. The circuit board via detection method according to claim 1, characterized in that: In each of the processing areas (500), d2-d1=0.05 mm.

3. The circuit board via detection method according to claim 1, characterized in that: When n≥2, the number of the first metal layer (100) is 1, the number of the second metal layer (200) is also 1, the first metal layer (100) is located on one of the core boards, and the second metal layer (200) is located on the other core board.

4. The circuit board via detection method according to claim 1, characterized in that: Step S3 further comprises laser drilling, where a tool hole (400) is formed at a position of each core plate corresponding to the tool hole position (530), wherein the tool hole (400) located at the first metal layer (100) passes through the first tool hole pad (120), and the tool hole (400) located at the second metal layer (200) passes through the second tool hole pad (220); In step S41, the conductive member is installed in all the tool holes (400).

5. The circuit board via detection method according to claim 4, characterized in that: In the step S4.1, before installing the conductive member, an isolation groove (310) is opened on the outer surfaces of the two third metal layers (300), and the isolation groove (310) is arranged around the outer circumference of the tool hole (400).

6. The circuit board via detection method according to claim 5, characterized in that: In step S3, When n=1, the core plate is placed between two third metal layers (300) for lamination, wherein a connection layer is sandwiched between the two third metal layers (300) and the core plate; When n≥2, all the core boards are stacked in sequence between the two third metal layers (300) and then pressed together, wherein a connecting layer is sandwiched between each two adjacent core boards and between the two third metal layers (300) and the adjacent core boards.

7. The circuit board via detection method according to claim 1, characterized in that: In the step S4.1, the conductive member is a metal pin.

8. The circuit board via detection method according to claim 1, characterized in that: The step between step S3 and step S4.2 also includes stacking the plates, stacking the bottom plate, the multilayer plate, and the protection plate in sequence, wherein the protection plate is spaced apart from the periphery of the tool hole (400).

9. The circuit board via detection method according to claim 8, characterized in that: The protection plate is provided with a clearance groove corresponding to the tool hole (400), the tool hole (530) is located in the clearance groove, and the periphery of the tool hole (400) and the inner wall of the clearance groove are arranged at intervals.

10. The circuit board via detection method according to claim 8 or 9, characterized in that: The protection plate is an aluminum plate.

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