A laser blind hole alignment target for multi-level HDI board

Abstract

The utility model discloses a kind of laser blind hole alignment targets of multi-stage HDI board, including core plate, four corners of the front of the core plate are evenly provided with first laser target group, and the number of laser targets of the first laser target group is equal to the number of laser blind hole stages of HDI board;Four corners of the back of the core plate are evenly provided with second laser target group, the second laser target group is relatively located below the first laser target group, and the number of laser targets of the second laser target group is equal to the number of laser blind hole stages of HDI board.The utility model by the target number of first laser target group and second laser target group is set to equal to the number of laser blind hole stages, can have corresponding laser target alignment reference when each stage laser blind hole is processed, to significantly improve the position accuracy of each stage blind hole processing, reduce the offset in superposition process.

Description

Technical Field

[0001] This utility model relates to the field of HDI blind via alignment design and processing technology, and more specifically, to a laser blind via alignment target for multi-stage HDI boards. Background Technology

[0002] Among existing PCB products, there is an HDI (High Density Interconnector) product. The difference between HDI boards and ordinary PCB boards is that HDI boards use micro-blind vias (0.076-0.127mm in diameter) and buried via technology, achieving three-dimensional interconnection through laser drilling. Ordinary PCBs, on the other hand, rely on mechanical through-holes (≥0.2mm in diameter) to achieve interlayer conductivity, occupying more wiring space, and the wiring density is only at the traditional level.

[0003] In current HDI board manufacturing, laser-etched blind via alignment is a crucial process. It ensures accurate alignment between internal interconnects and external vias on multilayer boards, guaranteeing the accurate operation of the circuit board. Traditionally, laser-etched blind vias involve first burning out the target of the inner layer pattern using a laser, then identifying the target and aligning it during production. However, in multilayer HDI board manufacturing, this process has a drawback: with numerous layers of laser-etched blind vias, the offset increases significantly during stacking, ultimately leading to product structural failure.

[0004] Therefore, how to improve the alignment structure of multi-stage HDI boards during laser blind via drilling has become an urgent problem to be solved. Utility Model Content

[0005] To overcome the problem of product structure failure caused by excessive layers and large offset of laser blind vias during the manufacturing process of existing multi-layer HDI boards, this utility model provides a laser blind via alignment target for multi-layer HDI boards.

[0006] The technical solution of this utility model is as follows: A laser blind via alignment target for a multi-stage HDI board, comprising a core board, characterized in that: The core board has a first laser target group at each of the four corners on the front side. The number of laser targets in the first laser target group is equal to the order of the laser blind vias of the HDI board. A second laser target group is provided at each of the four corners on the reverse side of the core board. The second laser target group is located below the first laser target group, and the number of laser targets in the second laser target group is equal to the order of the laser blind vias of the HDI board.

[0007] According to the above-described scheme of this utility model, the laser target includes a laser alignment ring and a laser target center.

[0008] According to the above-described scheme of this utility model, the diameter of the laser alignment ring is 9mm, and the diameter of the laser target is 3mm.

[0009] According to the above-described scheme of this utility model, a first depth control target group is provided on the outer side of the first laser target group, and a second depth control target group is provided on the outer side of the second laser target group.

[0010] According to the above-described scheme of this utility model, the first laser target group and the first depth control target group are arranged in parallel, and the second laser target group and the second depth control target group are arranged in parallel.

[0011] According to the above-described scheme, the depth control targets of the first depth control target group and the second depth control target group include depth control alignment rings and depth control target centers.

[0012] According to the above-described scheme of this utility model, the length and width of the depth control alignment ring are both 10mm, and the diameter of the depth control target is 0.5mm.

[0013] According to the above-described scheme of this utility model, the core board is provided with a mechanical drilling positioning target.

[0014] According to the above-described scheme of this utility model, the number of mechanical drilling positioning targets above the core board is one, and the number of mechanical drilling positioning targets below the core board is two.

[0015] According to the above-described scheme of this utility model, the mechanical drilling positioning target is provided with a first positioning ring, the first positioning ring is nested with a second positioning ring, and the second positioning ring is nested with a positioning target center.

[0016] The advantages of this utility model based on the above solution are as follows: 1. The core board of this utility model is provided with a first laser target group and a second laser target group at the four corners on the front and back sides respectively. The second laser target group is located below the first laser target group. The design of the two sets of targets being staggered vertically can effectively prevent the board from being pierced and the targets from being damaged when using depth control milling and laser cutting. 2. By setting the number of targets in the first laser target group and the second laser target group to be equal to the order of the laser blind hole, this utility model can provide a corresponding laser target alignment reference during the processing of each order of laser blind hole, thereby significantly improving the positional accuracy of the processing of each order of blind hole and reducing the offset during the stacking process. 3. This utility model sets up a laser target specifically for laser drilling machines to align blind holes, ensuring the positional accuracy of laser drilling. It also sets up a depth control target specifically for laser drilling machines to control the drilling depth accuracy, preventing drilling through or insufficient depth. By separating the alignment and depth control functions, it avoids mutual interference, simplifies the equipment identification logic, and improves the accuracy of both functions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the laser blind via stack structure of the fourth-order HDI board provided by this utility model; Figure 2 A schematic diagram of the L5 layer structure of the fourth-order HDI board provided by this utility model; Figure 3 A schematic diagram of the L6 layer structure of the fourth-order HDI board provided by this utility model.

[0019] The following are the labeling elements in the figure: 10. Front side of core board; 11. First laser target; 12. Second laser target; 13. Third laser target; 14. Fourth laser target; 15. First depth control target; 16. Second depth control target; 17. Third depth control target; 18. Fourth depth control target; 19. Mechanical drilling positioning target; 20. Core board surface; 21. Seventh laser target; 22. Eighth laser target; 23. Ninth laser target; 24. Tenth laser target; 25. Seventh depth control target; 26. Eighth depth control target; 27. Ninth depth control target; 28. Tenth depth control target. Detailed Implementation

[0020] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0021] It should be noted that when a component is referred to as "fixed," "set," or "connected" to another component, it may be located directly or indirectly on that other component. The terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or position based on the accompanying drawings, and are for ease of description only, and should not be construed as limiting the technical solution. The terms "first," "second," etc., are used for ease of description only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "Many" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0022] See Figures 1 to 3 This utility model provides a laser blind hole alignment target for a multi-stage HDI board, including a core board; A first laser target group is provided at each of the four corners of the front side 10 of the core board, and the number of laser targets in the first laser target group is equal to the order of the laser blind vias of the HDI board; a second laser target group is provided at each of the four corners of the back side of the core board, and the second laser target group is located below the first laser target group, and the number of laser targets in the second laser target group is equal to the order of the laser blind vias of the HDI board.

[0023] Specifically, in this embodiment, the core board is designed as a fourth-order HDI board. The L5 layer pattern on the front side 10 of the core board includes a first laser target group with a first laser target 11, a second laser target 12, a third laser target 13, and a fourth laser target 14. The first laser target 11 is used for alignment of first-order laser blind vias from L4 to L5 layers; the second laser target 12 is used for alignment of second-order laser blind vias from L3 to L5 layers; the third laser target 13 is used for alignment of third-order laser blind vias from L2 to L5 layers; and the fourth laser target 14 is used for... The alignment of fourth-order laser blind vias in layers L1 to L5; the pattern of layer L6 on the reverse side of the core board; the second laser target group is provided with a seventh laser target 21, an eighth laser target 22, a ninth laser target 23, and a tenth laser target 24. The seventh laser target is used for alignment of first-order laser blind vias in layers L7 to L6, the eighth laser target is used for alignment of second-order laser blind vias in layers L8 to L6, the ninth laser target is used for alignment of third-order laser blind vias in layers L9 to L6, and the tenth laser target is used for alignment of fourth-order laser blind vias in layers L10 to L6.

[0024] In fact, the core board of this invention has a first laser target group and a second laser target group respectively set at the four corners of the front and back sides. The second laser target group is located below the first laser target group. When using depth control milling and laser cutting, this effectively prevents the depth control milling from cutting through the board and damaging the targets due to the two targets being in the same position. Furthermore, by setting the number of targets in the first and second laser target groups to be equal to the order of the laser blind hole, there can be a corresponding laser target alignment reference when processing each order of laser blind hole, which significantly improves the positional accuracy of each order of blind hole processing and reduces the offset during the stacking process.

[0025] Furthermore, in this invention, the laser target includes a laser alignment ring and a laser target center. The diameter of the laser alignment ring is 9mm, and the diameter of the laser target center is 3mm. By using a large 9mm laser alignment ring, the laser equipment can quickly identify the position, reducing image recognition time. The 3mm diameter laser target center facilitates equipment identification and offset calculation. The laser targets in the first and second laser target groups are spaced 10mm apart to ensure independent identification and accurate positioning of multi-level targets without confusion or interference.

[0026] In this invention, a first depth control target group is provided on the outer side of each first laser target group, and a second depth control target group is provided on the outer side of each second laser target group. Furthermore, the first laser target group and the first depth control target group are arranged parallel to each other, and the second laser target group and the second depth control target group are arranged parallel to each other. By using depth control target groups to assist the laser targets, a dual positioning system can be formed, improving the axial accuracy of blind hole machining. Additionally, arranging the laser target groups and depth control target groups in parallel simplifies the algorithm design of the laser equipment and reduces the complexity of equipment debugging.

[0027] In fact, the first depth control target group is provided with a first depth control target 15, a second depth control target 16, a third depth control target 17, and a fourth depth control target 18. The first depth control target 15 is used for graphic alignment of the first laser target 11, the second depth control target 16 is used for graphic alignment of the second laser target 12, the third depth control target 17 is used for graphic alignment of the third laser target 13, and the fourth depth control target 18 is used for graphic alignment of the fourth laser target 14. The second depth control target group is provided with a seventh depth control target 25, an eighth depth control target 26, a ninth depth control target 27, and a tenth depth control target 28. The seventh depth control target 25 is used for graphic alignment of the seventh laser target 15, the eighth depth control target 26 is used for graphic alignment of the eighth laser target 16, the ninth depth control target 27 is used for graphic alignment of the ninth laser target 17, and the tenth depth control target 28 is used for graphic alignment of the tenth laser target 18.

[0028] Furthermore, in this invention, the distance between the laser target and the depth control target is designed to be 20mm, and the distance between the depth control target and the edge of the core board is designed to be >10mm. After each pair of core boards is pressed together, when making laser blind holes, alignment is first achieved using the depth control target, and then a portion is cut off according to the thickness of the PP layer using a depth control milling process. Further, the remaining PP on the target is burned off using a laser to expose the target pattern, and the laser drilling machine then grasps and positions the laser target pattern to begin production within the board.

[0029] Specifically, the depth control targets in the first and second depth control target groups include a depth control alignment ring and a depth control target center. The depth control alignment ring has a length and width of 10 mm, and the depth control target center has a diameter of 0.5 mm. The depth control alignment ring is easier to identify for rotation angle correction, while the 0.5 mm diameter target center provides precise focus positioning, thereby achieving precise depth control.

[0030] Furthermore, the core board is provided with mechanical drilling positioning targets 19. There is one mechanical drilling positioning target 19 on the upper part of the core board, and two mechanical drilling positioning targets 19 on the lower part of the core board. Each mechanical drilling positioning target 19 is provided with a first positioning ring, a second positioning ring nested within the first positioning ring, and a positioning target center nested within the second positioning ring. By setting different numbers of mechanical drilling targets on the upper and lower parts of the core board, combined with nested positioning rings, traditional mechanical drilling processes can be maintained, and the difference in quantity prevents mistake-proofing, avoiding errors in processing direction.

[0031] Specifically, in this embodiment, the first positioning ring of the mechanical drilling positioning target 19 has a diameter of 9mm, the second positioning ring has a diameter of 6mm, and the positioning target center has a diameter of 3.175mm. In reality, most mechanical drilling positioning targets only use a 9mm diameter first positioning ring and a 3.175mm diameter positioning target center. However, when jumping directly from the 9mm first positioning ring to the 3.175mm positioning target center, the vision system needs to quickly switch the recognition magnification, which can easily affect accuracy due to field-of-view shift caused by magnification switching. The 6mm second positioning ring, with a size between the 9mm first positioning ring and the 3.175mm positioning target center, can serve as a magnification transition reference, reducing positioning fluctuations caused by magnification switching.

[0032] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A laser blind via alignment target for a multi-stage HDI board, comprising a core board, characterized in that: The core board has a first laser target group at each of the four corners on the front side. The number of laser targets in the first laser target group is equal to the order of the laser blind vias of the HDI board. A second laser target group is provided at each of the four corners on the reverse side of the core board. The second laser target group is located below the first laser target group, and the number of laser targets in the second laser target group is equal to the order of the laser blind vias of the HDI board.

2. The laser blind via alignment target for a multi-stage HDI board according to claim 1, characterized in that, The laser target includes a laser alignment ring and a laser target center.

3. The laser blind via alignment target for a multi-stage HDI board according to claim 2, characterized in that, The diameter of the laser alignment ring is 9mm, and the diameter of the laser target is 3mm.

4. The laser blind via alignment target for a multi-stage HDI board according to claim 1, characterized in that, A first depth control target group is provided on the outer side of the first laser target group, and a second depth control target group is provided on the outer side of the second laser target group.

5. The laser blind via alignment target for a multi-stage HDI board according to claim 4, characterized in that, The first laser target group and the first depth control target group are arranged in parallel, and the second laser target group and the second depth control target group are arranged in parallel.

6. The laser blind via alignment target for a multi-stage HDI board according to claim 5, characterized in that, The depth control targets of the first and second depth control target groups include depth control alignment rings and depth control target centers.

7. The laser blind via alignment target for a multi-stage HDI board according to claim 6, characterized in that, The length and width of the depth control alignment ring are both 10 mm, and the diameter of the depth control target is 0.5 mm.

8. The laser blind via alignment target for a multi-stage HDI board according to claim 1, characterized in that, The core board is equipped with a mechanical drilling positioning target.

9. The laser blind via alignment target for a multi-stage HDI board according to claim 8, characterized in that, The number of mechanical drilling positioning targets above the core board is one, and the number of mechanical drilling positioning targets below the core board is two.

10. A laser blind via alignment target for a multi-stage HDI board according to claim 9, characterized in that, The mechanical drilling positioning target is provided with a first positioning ring, a second positioning ring nested within the first positioning ring, and a positioning target center nested within the second positioning ring.

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