A circuit board back drill fixing structure and a substrate

Abstract

The utility model belongs to back drill related technical field especially, and it is a kind of circuit board back drill fixed structure and substrate, be provided with fixed groove by being set on fixed plate, and the first locating hole is set to fixed groove periphery side;And circuit board subassembly, circuit board subassembly is provided with connecting surface and fixing piece, and connecting surface is set on fixed groove in alignment, to make the element on connecting surface set in fixed groove;Connecting surface periphery side is set in periphery side and is provided with the second locating hole;Among them, the first locating hole and the second locating hole are in alignment and are fixed by fixing piece. It is with the simple structure to lower cost, and the circuit board is planed in the mode of not pressing down circuit board periphery side, to make the effect of back drill better.

Description

Technical Field

[0001] This utility model belongs to the technical field of back drilling, and in particular relates to a circuit board back drilling fixing structure and a substrate. Background Technology

[0002] Back drilling is a crucial process for printed circuit boards (PCBs). The purpose of back drilling is to remove vias that do not serve any connection or transmission function, preventing reflection, scattering, and delays in high-speed signal transmission, which can lead to signal distortion. Back drilling requires flattening the PCB to ensure more complete signal transmission through the drilled vias. However, one surface of a PCB typically contains electronic components such as plugs and sockets, making the flattening process quite challenging.

[0003] In existing technologies, the circuit board is usually clamped on both sides and suspended from below to allow for back drilling through mechanical flatness. However, these structures are not only complex and costly, but also prone to damaging the electronic components around the circuit board. Utility Model Content

[0004] To address the technical problem that "existing back-drilling fixing structures are complex, costly, and prone to damaging electronic components on the periphery of the circuit board," this utility model proposes a circuit board back-drilling fixing structure and a substrate.

[0005] The present invention solves the above problems through the following technical solution: In a first aspect, this utility model proposes a circuit board back-drill fixing structure, comprising: A fixing plate is provided with a fixing groove, and a first positioning hole is provided on the periphery of the fixing groove; and The circuit board assembly has a connecting surface and a fixing component. The connecting surface is aligned with a fixing groove so that the components on the connecting surface are placed in the fixing groove. A second positioning hole is provided on the periphery of the connecting surface. The first positioning hole and the second positioning hole are aligned and fixed by a fastener.

[0006] A fixing plate is provided with a fixing groove, and a first positioning hole is provided on the periphery of the fixing groove; a circuit board assembly is provided, and the circuit board assembly is provided with a connecting surface and a fixing member. The connecting surface is aligned with the fixing groove so that the components on the connecting surface are placed in the fixing groove; a second positioning hole is provided on the periphery of the connecting surface; wherein the first positioning hole and the second positioning hole are aligned and fixed by the fixing member. This simple structure allows the circuit board to be planed flat at a lower cost and without damaging the periphery of the circuit board, thereby improving the effect of back drilling.

[0007] In some embodiments, the fixing slot is provided with a first cavity and at least one second cavity, the second cavity being disposed around the periphery of the first cavity so that the first cavity is used to accommodate components of the circuit board assembly, and the second cavity being disposed in an area outside the circuit board assembly.

[0008] In some implementations, the first positioning hole is configured as a through hole and / or as a groove structure with a depth of at least 0.5 mm.

[0009] In some embodiments, the fixing groove is provided with multiple support protrusions.

[0010] In some embodiments, at least a first platform is provided around the first positioning hole so that there is a gap between the first positioning hole and the fixing groove, and a second platform is also provided around the second positioning hole to position it with the first platform.

[0011] In some embodiments, the fixing plate is set as a rectangle, with opposite two sides of the fixing plate adjacent to the same first side, and a first platform and a first positioning hole provided at both ends of the first side; at least one extension is provided at the second side opposite to the first side, and the extension is provided with a first platform and a first positioning hole, so that a triangular positioning is formed between the first positioning holes.

[0012] In some embodiments, the circuit board assembly is further provided with a positioning element, which is disposed adjacent to the connection surface, and the fixing plate is provided with a positioning plate, which is disposed adjacent to the fixing groove, so that the positioning element is disposed on the positioning plate.

[0013] Secondly, this utility model proposes a substrate, including a circuit board back-drilling fixing structure as described in any of the first aspects, wherein the circuit board back-drilling fixing structures are arranged in an array on the substrate.

[0014] In some embodiments, the circuit board back-drilling fixing structure is integrally formed with the substrate, or the circuit board back-drilling fixing structure is detachably formed on the substrate.

[0015] In some embodiments, at least one third positioning hole is provided on the substrate to achieve visual positioning.

[0016] The beneficial effects of this utility model of a circuit board back-drill fixing structure and substrate are: A fixing plate is provided with a fixing groove, and a first positioning hole is provided on the periphery of the fixing groove; a circuit board assembly is provided, and the circuit board assembly is provided with a connecting surface and a fixing member. The connecting surface is aligned with the fixing groove so that the components on the connecting surface are placed in the fixing groove; a second positioning hole is provided on the periphery of the connecting surface; wherein the first positioning hole and the second positioning hole are aligned and fixed by the fixing member. This simple structure allows the circuit board to be planed flat at a lower cost and without damaging the periphery of the circuit board, thereby improving the effect of back drilling. Attached Figure Description

[0017] Figure 1 This is a structural diagram of the fixing plate of the circuit board back-drill fixing structure of this utility model; Figure 2 This is a structural diagram of the circuit board assembly of the circuit board back-drill fixing structure of this utility model; Figure 3 This is a diagram showing the combination of the fixing plate and the circuit board assembly in the circuit board back-drilling fixing structure of this utility model; Figure 4 This is a schematic diagram of the substrate structure of the circuit board back-drill fixing structure of this utility model.

[0018] Figure 5 for Figure 4 Enlarged view of part a.

[0019] Figure label: 1. Fixing plate; 11. Fixing groove; 111. First cavity; 112. Second cavity; 113. Support protrusion; 12. First positioning hole; 13. First platform; 14. First side; 15. Second side; 2. Circuit board assembly; 21. Connecting surface; 22. Fixing component; 23. Second positioning hole; 24. Positioning component; 25. Second platform; 3. Substrate; 31. Third positioning hole. Detailed implementation method: It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of this utility model can be combined with each other. The detailed description in the specific embodiments should be understood as an explanation of the spirit of this utility model and should not be regarded as an improper limitation of this utility model.

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the specific technical solutions of this utility model will be further described in detail below with reference to the accompanying drawings of the embodiments of this utility model. The following embodiments are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0021] In the embodiments of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0022] Furthermore, in this embodiment of the invention, directional terms such as "upper," "lower," "left," and "right" are defined relative to the positions of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the position of the components in the accompanying drawings.

[0023] In the embodiments of this utility model, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium.

[0024] In embodiments of this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0025] In this embodiment of the invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this embodiment of the invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant information in a specific manner.

[0026] Example 1: like Figure 1 As shown, this embodiment proposes a circuit board back-drilling fixing structure, including a fixing plate 1 and a circuit board assembly 2: The fixing plate 1 has a fixing groove 11, and the fixing groove 11 has a first positioning hole 12 on its periphery; and The circuit board assembly 2 is provided with a connecting surface 21 and a fixing member 22. The connecting surface 21 is aligned and disposed on the fixing groove 11 so that the components on the connecting surface 21 are disposed in the fixing groove 11. A second positioning hole 23 is provided on the periphery of the connecting surface 21. The first positioning hole 12 and the second positioning hole 23 are aligned and fixed by the fastener 22.

[0027] Specifically, the fixing plate 1 is provided with a fixing groove 11, which is usually located at the center of the fixing plate 1. The fixing groove 11 is used to accommodate electronic components such as plugs and sockets on the circuit board assembly 2, and also to prevent damage to the components during back drilling. The depth of the fixing groove 11 is usually much longer than the height of the electronic component itself to prevent the electronic component from hitting the bottom of the fixing groove 11 during back drilling. The circuit board assembly 2 is provided with a connecting surface 21. The shape and width of the fixing groove 11 are usually adapted to the connecting surface 21, and the width of the fixing groove 11 is greater than that of the connecting surface 21 to prevent the electronic components on the connecting surface 21 from hitting the periphery or bottom of the fixing groove 11 during back drilling. The groove width is preferably at least 0.3 mm greater than that of the connecting surface 21. This setting can also prevent component offset. Based on the text frame / solder resist, a safety distance of more than 0.5 mm is maintained to prevent component offset and prevent the parts from sinking into the machine plane. At the same time, the linear chamfer of the fixing groove 11 is also provided with rounded corners (more than 1.2 mm) to prevent scratches on the circuit board assembly 2 during installation.

[0028] Meanwhile, in order to make the placement of the circuit board assembly 2 more accurate and faster, the shape of the fixing groove 11 is as parallel as possible to the connecting surface 21 and follows a straight / oblique line to reduce the support of small concave / convex points, making it inconvenient to load and unload the board during back-drilling production, and reducing the risk of scratching / pressing / collision damage to the PCBA.

[0029] A first positioning hole 12 is provided around the fixed groove 11, and a second positioning hole 23 is provided around the connecting surface 21 for alignment. A fastener 22 is fixedly positioned by passing through the second positioning hole 23 and the first positioning hole 12. The fastener 22 can be a screw, a pin, or the like.

[0030] A fixing plate 1 has a fixing groove 11 with a first positioning hole 12 on its periphery; and a circuit board assembly 2 has a connecting surface 21 and a fixing member 22. The connecting surface 21 is aligned with the fixing groove 11 so that the components on the connecting surface 21 are placed in the fixing groove 11; a second positioning hole 23 is provided on the periphery of the connecting surface 21; wherein the first positioning hole 12 and the second positioning hole 23 are aligned and fixed by the fixing member 22. This simple structure allows the circuit board to be planed flat at a lower cost without damaging the periphery of the circuit board, thus improving the effect of back drilling.

[0031] Example 2: exist Figure 1 Based on, combined Figures 2-3 As shown, this embodiment further defines and explains the structure proposed in Embodiment 1: In some embodiments, the fixing groove 11 is provided with a first cavity 111 and at least one second cavity 112, the second cavity 112 being disposed around the first cavity 111 so that the first cavity 111 is used to accommodate the components of the circuit board assembly 2, and the second cavity 112 being disposed in an area outside the circuit board assembly 2.

[0032] Specifically, the fixing groove 11 is provided with a first cavity 111 and at least one second cavity 112. The first cavity 111 and the second cavity 112 are connected and disposed on both sides of the first cavity 111, so that when the circuit board assembly 2 is disposed on the fixing groove 11, the slot of the second cavity 112 is disposed in an area outside the circuit board assembly 2. Thus, after the circuit board assembly 2 is back drilled, the second cavity 112 can be inserted into the fixing groove 11 and the circuit board assembly 2 can be taken out, so that the first cavity 111 can be used to accommodate the components of the circuit board assembly 2.

[0033] In some embodiments, the first positioning hole 12 is configured as a through hole and / or as a groove structure with a depth of at least 0.5 mm.

[0034] Specifically, the first positioning hole 12 can be configured as a through hole and / or as a groove structure with a depth of at least 0.5 mm. When planing the circuit board assembly 2, the first positioning hole 12 and the second positioning hole 23 are usually aligned and then fixed by sinking the fastener 22. The sinking height is usually at least 0.5 mm to ensure that the circuit board assembly 2 can be planed flat.

[0035] In some embodiments, a plurality of support protrusions 113 are provided in the fixing groove 11.

[0036] Specifically, multiple support protrusions 113 are provided in the fixing groove 11 to avoid insufficient contact area of ​​the connecting surface 21 in the middle of the fixing groove 11, which could cause warping or bending problems.

[0037] In some embodiments, at least a first platform 13 is provided around the first positioning hole 12 so that there is a gap between the first positioning hole 12 and the fixing groove 11, and a second platform 25 is also provided around the second positioning hole 23 to position it with the first platform 13.

[0038] Specifically, at least a first platform 13 is provided around the first positioning hole 12. The first platform 13 allows the first positioning hole 12 to be at a certain distance from the fixing groove 11, thereby reducing the risk of breakage. At the same time, a second platform 25 is also provided around the first positioning hole 12 on the circuit board assembly 2. The second platform 25 can avoid electronic components, thereby preventing the stress of the board from affecting the surrounding electronic components during fixing. At the same time, the second platform 25 can also prevent breakage caused by the second positioning hole 23 being too close to the surrounding components.

[0039] In some embodiments, the fixing plate 1 is configured as a rectangle, with the opposite two sides of the fixing plate 1 adjacent to the same first side 14. The first side 14 is provided with a first platform 13 and a first positioning hole 12 at both ends. At least one extension is provided at the second side 15 opposite to the first side 14, and the extension is provided with the first platform 13 and the first positioning hole 12, so that a triangular positioning is formed between the first positioning holes 12.

[0040] Specifically, the fixing plate 1 is preferably rectangular. The two opposite sides of the rectangle (usually the longer sides) are adjacent to the same first side 14. Each end of the first side 14 is provided with a first platform 13 and a first positioning hole 12. An extension is provided on the opposite second side 15, extending towards the center of the second side 15. The first platform 13 and the first positioning hole 12 are located near the free end of the extension. By providing three first positioning holes 12, triangular positioning can be achieved, thereby improving the stability of the circuit board assembly 2.

[0041] In some embodiments, the circuit board assembly 2 is further provided with a positioning member 24, which is disposed adjacent to the connecting surface 21. The fixing plate 1 is provided with a positioning plate, which is disposed adjacent to the fixing groove 11, so that the positioning member 24 is disposed on the positioning plate.

[0042] Specifically, the positioning element 24 can typically be a relatively long external structure. When it is adjacent to the connecting surface 21, its lower surface is the same as the connecting surface 21. Furthermore, a positioning plate is provided on the fixing plate 1 for alignment. The positioning plate is adjacent to the fixing groove 11 so that when the connecting surface 21 is set on the fixing groove 11, the positioning element 24 can be just placed on the positioning plate. With the assistance of the positioning plate, the positioning element 24 is completely attached to the positioning plate. While achieving the effect of positioning and fixing, it can also be used to determine whether the circuit board assembly 2 is completely flat based on whether the positioning element 24 is completely attached to the positioning plate.

[0043] In some more specific embodiments, after the circuit board assembly 2 is mounted on the fixing plate 1, the flatness of the circuit board assembly 2 can be determined from the side by height detection.

[0044] Example 3: like Figures 4-5 As shown, this embodiment proposes a substrate 3, including a circuit board back-drilling fixing structure as described in either Embodiment 1 or Embodiment 2, wherein the circuit board back-drilling fixing structure is arranged in an array on the substrate 3.

[0045] Specifically, 4-6 circuit board back-drilling fixing structures as described in either Embodiment 1 or Embodiment 2 can be provided. For example, when there are 4, they can be arranged in pairs, and when there are 6, they can be arranged in two rows of three. Furthermore, the substrate 3 can be a PNL flat panel, wherein the PNL panel is composed of 4-6 PCS (horizontal / vertical arrangement), designed to be centered on the drilling machine, with a PCS spacing of 50mm, so that the PCS avoid the screw holes of the drilling machine.

[0046] In some embodiments, the circuit board back-drilling fixing structure is integrally disposed with the substrate 3, or the circuit board back-drilling fixing structure is detachably disposed on the substrate 3.

[0047] Specifically, the circuit board back-drill fixing structure can be integrally set with the substrate 3, for example, the fixing plate 1 can be integrally set with the substrate 3. Alternatively, the circuit board back-drill fixing structure can be detachably set on the substrate 3. For example, the circuit board back-drill fixing structure can be a rectangular module, with the length and width of the rectangular module being the same, while the structure of the internal fixing groove 11 is different. This allows for different board surface fixing back-drills to be achieved by replacing the rectangular module, thereby enabling a single substrate 3 to be used for the production of multiple board surfaces, further reducing cost. Disassembly can be performed using snap-fit ​​structures, alignment fixing hole fixing structures, etc.

[0048] In some embodiments, at least one third positioning hole 31 is provided on the substrate 3 to achieve visual positioning.

[0049] Specifically, the substrate 3 is provided with at least one third positioning hole 31. The function of the third positioning hole 31 can be to serve as a fixing hole between the substrate 3 and the platform, preventing the substrate 3 from moving during back drilling. It can also serve as a CCD scanning hole, drilled by a milling die. This allows for approximate positioning through the third positioning hole 31 during back drilling, and further precise positioning through the first positioning hole 12.

[0050] Example 4: This embodiment proposes a practical method for fixing the circuit board assembly 2 and the fixing plate 1 to each other: In some embodiments, the fabrication and alignment of the substrate 3 include the following steps: S1. Analyze the customer's circuit board assembly 2. For the parts on the connection surface 21, the fixing groove 11 is reduced inward by 0.3mm on one side. Confirm the length / width / height of the parts (the distance around the parts is increased). Based on the text box / solder mask, the safety distance is more than 0.5mm to avoid the parts from shifting during assembly and prevent the parts from sinking to the machine plate plane.

[0051] S2. All outer lines of the mold are rounded (1.2mm or more) to avoid scratching the PCBA during back drilling. A 30*50mm gap is left on the left and right sides of the mold to facilitate board removal after back drilling. The mold shape should be as parallel as possible, with straight / diagonal lines to reduce the support of small concave / convex points. Back drilling makes it inconvenient to load and unload the board, and there is a risk of scratching / pressing / collision to the PCBA. The mold is equipped with a first positioning hole 12 and a second positioning hole 23.

[0052] S3. For positioning holes, select holes with a diameter of 3.0mm or more inside the plate (drilled by CCD machine). Provide as many support points as possible in the mold, and positioning holes may not need to be drilled. Select triangular positioning, and leave as much solid material as possible on the left and right sides of the positioning hole to reduce hole breakage. When the positioning hole is limited, the positioning hole can be designed to be drilled halfway.

[0053] S4. Perform panelization design on substrate 3, with 4-6 PNL panels (horizontal / vertical arrangement), centered on the drilling machine, with a 50mm spacing between PCs, avoiding the screw holes of the drilling machine (due to the high centering accuracy of the drilling characteristics, the minimum distance between PCs and the edge of the bakelite board is 50mm); add positioning holes on all four sides of the panel, 3 at the bottom left corner (3.175mm, center distance 10mm), and 2 at the other corners; (the outermost hole is the panel fixing hole, and the inner hole is the CCD scanning positioning hole, which must not be damaged), the panel positioning holes are drilled by the forming machine during the die-cutting process; the die shape is cut out (the bakelite board thickness of the drilling machine is 10mm; if the part sinking depth is insufficient, stack a 3.0mm / piece jig panel, and fix the PNL side positioning holes onto the bakelite board).

[0054] S5. Place the drilled bakelite board on the forming machine table in front of the gong mold, aligning it horizontally and vertically with one corner of the machine table. Read in the forming program, adjust the coordinates, and avoid the screw holes of the back drilling machine table to prevent it from being dropped by the forming gong and affecting the back drilling accuracy.

[0055] S6. When making the mold, the placement direction of the bakelite board must be confirmed to avoid the machine tool being opposite to the design method in the data.

[0056] S7. The bakelite board of the back drilling machine base is for single-sided use, with the screw holes facing upwards and adhesive tape applied to fix the forming machine base.

[0057] S8. Drill holes in the mold first, assemble the entire single-axis assembly, and complete the drilling in batches. First, drill the overlapping panel, then drill the holes in the bakelite board. Do not move it.

[0058] S9. After drilling, a set of molds is made on two axes and finished in two milling operations to avoid burrs on the edges of the bakelite board. A brand new milling cutter is used.

[0059] S10. After the first PCS is drilled, remove the panel and place the PCBA to be re-drilled on the mold according to the re-drilling method. Check if there are any bumps pushing against the board. Check that the PCBA is level with the mold surface on all four sides. If there are any bumps, rework and optimize the mold shape and forming strip to achieve a level effect.

[0060] S11. Mold assembly: The back drill table is fixed with screws on the bakelite board, and the panel is fixed to the bakelite board with pins. The PCBA placement area is planed to ensure that the panel plane is level with the drilling machine.

[0061] S12. The back drill table is fixed to the machine table with a bakelite board, and the stacked panels are fixed with pins at the four corners of the outer side of the splicing board.

[0062] S13. Plane the mold 10mm inwards / outwards along its outline to ensure it is level with the machine. This is done by scanning the four corner positioning holes with a CCD back-drilling machine and drilling the mold mounting plate positioning holes. A brand new drill bit is used, employing a planing drilling program with a hole diameter of 3.2mm, a hole center-to-center distance of 2.0mm, and a drilling depth of 0.5mm. After planing, confirm the flatness; any uneven areas are re-drilled to achieve a level surface.

[0063] S14. If the positioning of the first drill hole (4 NPTHs) in the PCS scan by the CCD back drilling machine is abnormal, the machine will stop and alarm (the scanning positioning hole must be in the empty space of the mold screw).

[0064] S15. After scanning is completed and personnel are confirmed, start the back-drilling operation.

[0065] The serial numbers of the utility model embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above are only preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent device or equivalent process transformation made based on the content of this utility model specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this utility model.

Claims

1. A circuit board back-drill fixing structure, characterized in that, include: The fixing plate (1) is provided with a fixing groove (11), and the fixing groove (11) is provided with a first positioning hole (12) on its periphery; as well as The circuit board assembly (2) is provided with a connecting surface (21) and a fixing member (22). The connecting surface (21) is aligned with the fixing groove (11) so that the components on the connecting surface (21) are placed in the fixing groove (11). The connecting surface (21) is provided with a second positioning hole (23) on its periphery. The first positioning hole (12) and the second positioning hole (23) are aligned and fixed by the fastener (22).

2. The circuit board back-drill fixing structure according to claim 1, characterized in that, The fixing groove (11) is provided with a first cavity (111) and at least one second cavity (112), the second cavity (112) being disposed on the periphery of the first cavity (111) so that the first cavity (111) is used to accommodate the components of the circuit board assembly (2), and the second cavity (112) being disposed in an area outside the circuit board assembly (2).

3. The circuit board back-drill fixing structure according to claim 1, characterized in that, The first positioning hole (12) is configured as a through hole and / or as a groove structure with a depth of at least 0.5 mm.

4. The circuit board back-drill fixing structure according to claim 1, characterized in that, The fixing groove (11) is provided with multiple supporting protrusions (113).

5. The circuit board back-drill fixing structure according to claim 1, characterized in that, At least a first platform (13) is provided around the first positioning hole (12) so that there is a gap between the first positioning hole (12) and the fixing groove (11). A second platform (25) is also provided around the second positioning hole (23) to position it with the first platform (13).

6. The circuit board back-drill fixing structure according to claim 5, characterized in that, The fixing plate (1) is rectangular, and the two opposite sides of the fixing plate (1) are adjacent to the same first side (14). The first platform (13) and the first positioning hole (12) are provided at both ends of the first side (14). At least one extension is provided at the second side (15) opposite to the first side (14). The first platform (13) and the first positioning hole (12) are provided on the extension, so that a triangular positioning is formed between the first positioning holes (12).

7. The circuit board back-drill fixing structure according to claim 1, characterized in that, The circuit board assembly (2) is also provided with a positioning element (24), which is disposed adjacent to the connecting surface (21). The fixing plate (1) is provided with a positioning plate, which is disposed adjacent to the fixing groove (11) so that the positioning element (24) is disposed on the positioning plate.

8. A substrate, characterized in that, The circuit board back-drilling fixing structure as described in any one of claims 1-7 is arranged in an array on the substrate (3).

9. The substrate according to claim 8, characterized in that, The circuit board back-drilling fixing structure is integrally formed with the substrate (3), or the circuit board back-drilling fixing structure is detachably set on the substrate (3).

10. The substrate according to claim 9, characterized in that, The substrate (3) is provided with at least one third positioning hole (31) to achieve visual positioning.

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