AI computing power card HDI board alignment structure

Abstract

The utility model relates to an AI computing power card HDI board alignment structure, including inner layer and outer layer, four corner parts of inner layer are equipped with four first alignment target position, four first alignment target position respectively are first target position, second target position, third target position and fourth target position, first target position and second target position are arranged coaxially along the horizontal direction, third target position and first target position are opposite along the vertical direction, fourth target position and second target position are aligned along the vertical direction, the vertical interval difference of third target position and fourth target position is 3mm, the outer layer is equipped with four second alignment target position with first alignment target position position consistent. The utility model has the advantages of being capable of improving HDI board alignment precision, reducing product scrappage risk and guaranteeing the stability and consistency of production process.

Description

Technical Field

[0001] This utility model relates to the field of HDI board production technology, specifically to an alignment structure for an AI computing power card HDI board. Background Technology

[0002] Traditional HDI products are typically characterized by their thinness and compact size, with a board thickness generally within 3.2mm. However, in the high-end field of AI computing cards, due to the demand for high performance, HDI boards have more layers and increased thickness, for example, reaching 3.8mm. Simultaneously, the aspect ratio of HDI through-hole plating reaches as high as 19. Furthermore, the process design is more complex, encompassing numerous steps such as through-hole and blind plating, through-hole plating, plug and capping plating, and copper reduction through-hole sealing. The specific process is as follows: lamination - target drilling - browning - laser drilling - plasma drilling - blind through-hole AOI - blind through-hole filling - copper reduction - mechanical drilling - board plating - outer layer selective plating - through-hole patterning - patterned through-hole plating - film removal - plug - dry film sealing - copper reduction - film removal - plug grinding and copper reduction - capping plating - outer layer.

[0003] In such a production process, the high aspect ratio electroplating itself has poor uniformity, and the whole process includes four copper plating and four copper reduction processes (browning, copper reduction, and resin grinding copper reduction), which makes it difficult to guarantee the uniformity of copper thickness. In addition, the outer layer alignment hole is a large hole of 125mil. During grinding, due to the uneven copper thickness, the alignment hole is easily deformed, which in turn causes abnormal alignment of the outer layer, ultimately leading to product scrap. Utility Model Content

[0004] The purpose of this invention is to provide an AI computing power card HDI board alignment structure that can improve HDI board alignment accuracy, reduce product scrap risk, and ensure the stability and consistency of the production process.

[0005] An AI computing power card HDI board alignment structure includes an inner layer and an outer layer. The inner layer has four first alignment target positions at its four corners. The four first alignment target positions are a first target position, a second target position, a third target position, and a fourth target position. The first target position and the second target position are arranged coaxially along the horizontal direction. The third target position is aligned with the first target position along the vertical direction. The fourth target position is aligned with the second target position along the vertical direction. The vertical distance difference between the third target position and the fourth target position is 3mm. The outer layer has four second alignment target positions that are in the same position as the first alignment target positions.

[0006] In the above scheme, the four first alignment targets of the inner layer form a fixed reference coordinate system. The first and second targets are arranged horizontally and coaxially, the third target is vertically aligned with the first target, and the fourth target is vertically aligned with the second target. This arrangement constructs a regular framework, enabling the outer layer to be accurately aligned with the inner layer through the first and second alignment targets. This avoids alignment abnormalities caused by deformation of the alignment holes due to uneven copper thickness. The 3mm vertical spacing difference between the third and fourth targets serves as a foolproof mechanism, providing a unique directional marker for the entire alignment structure. Through this special spacing difference, operators can easily determine the correct installation direction and position, avoiding alignment errors. This ensures the stability and consistency of the production process, greatly reduces product scrap due to alignment abnormalities, and significantly improves the production yield of AI computing power card HDI boards, thereby reducing production costs.

[0007] Furthermore, when the via ring of the HDI board is smaller than that of the blind via, the four first alignment targets are set in all layers of the inner layer.

[0008] In the above scheme, when aligning the outer and inner layers, both vias and blind vias need to be aligned simultaneously. When the via ring size is smaller than that of the blind via, the via may occupy a more critical position in the overall circuit layout, responsible for the transmission of some key signals. Since the vias run through the entire HDI board and connect multiple inner layers, their positional accuracy directly affects the stability and accuracy of signal transmission between different layers. Setting four first alignment targets in all inner layers can provide a precise positional reference for the vias in each layer, ensuring that the vias in each layer are accurately aligned in space, so that signals can be smoothly transmitted between different layers through the vias, reducing signal loss and interference.

[0009] Furthermore, when the blind via ring of the HDI board is smaller than that of the through hole, and the outer layer is L1 and LN layers, the four first alignment targets are only set in the inner layer L2 and LN-1 layers.

[0010] In the above scheme, when aligning the outer and inner layers, both through holes and blind holes need to be aligned simultaneously. When the blind hole ring of the HDI board is smaller than that of the through hole, blind hole alignment is the primary focus. The L2 and LN-1 layers are close to the two outer layers L1 and LN, respectively. Selecting the L2 and LN-1 layers as alignment targets is an optimization of production efficiency and cost while meeting the blind hole alignment accuracy requirements. These two layers can reflect the main positional relationship and changing trend of blind holes in the entire inner layer structure. By accurately aligning the blind holes in these two layers, the alignment accuracy of blind holes in other layers can be guaranteed to a certain extent, avoiding unnecessary waste of resources.

[0011] Furthermore, the four first alignment targets are circular structures with a target diameter of 137 mil.

[0012] In the above scheme, the circular target with a diameter of 137 mil is of moderate size. During the manufacturing process, both manual visual inspection and automated optical inspection equipment can more clearly and accurately identify the target. The circular structure is isotropic and has no directional issues. Compared with other irregularly shaped targets, it is easier for the inspection system to quickly locate and identify it, thereby improving the accuracy of alignment between the outer and inner layers and reducing electrical connection problems caused by misalignment. At the same time, the circular structure is relatively simple and easier to implement using common photolithography, etching and other processes, which can ensure the dimensional accuracy and shape consistency of the target.

[0013] Furthermore, the target diameter of the second aligning target is not less than the target diameter of the first aligning target.

[0014] In the above scheme, during outer layer alignment, the optical equipment needs to simultaneously capture the first alignment target of the inner layer and the second alignment target of the outer layer. A slightly larger second alignment target provides the equipment with more capture tolerance, preventing alignment failure due to slight misalignment. During multilayer lamination, each layer exhibits minute misalignment; appropriately enlarging the diameter of the second alignment target can absorb accumulated errors from previous processes, ensuring the final interlayer alignment accuracy.

[0015] Furthermore, the concentricity error between the second and first aligned target positions is between -1 mil and 1 mil.

[0016] In the above scheme, the extremely small concentricity error range ensures the high accuracy of the alignment process between the outer and inner layers. In HDI board manufacturing, the precise alignment of blind vias and through-holes is crucial. The first and second alignment targets serve as positioning references, and their high-precision control of concentricity enables blind vias and through-holes to be accurately aligned. This helps to avoid problems such as poor circuit connection, short circuit or open circuit caused by misalignment, improves the yield rate in the production process, and reduces the scrap cost caused by alignment error.

[0017] Furthermore, the copper thickness uniformity error of the four first alignment target sites and the four second alignment target sites is between -1.5μm and 1.5μm.

[0018] In the above scheme, when the copper thickness uniformity error is strictly controlled between -1.5μm and 1.5μm, the surface flatness of the first and second alignment targets is higher. In the optical recognition system, the uniform copper thickness allows the target to reflect a clearer and more stable image. This helps the optical detection equipment to more accurately capture the edge and center positions of the first alignment target and the four second alignment targets, reducing image blurring or distortion caused by uneven copper thickness. This improves the accuracy of position recognition of the first alignment target and the four second alignment targets during the alignment process, providing a foundation for high-precision alignment.

[0019] This invention provides an AI computing power card HDI board alignment structure that improves HDI board alignment accuracy, reduces product scrap risk, and ensures production process stability and consistency. The four first alignment targets in the inner layer form a fixed reference coordinate system. The first and second targets are horizontally coaxially arranged, the third target is vertically aligned with the first target, and the fourth target is vertically aligned with the second target. This arrangement creates a regular framework, allowing the outer layer to accurately align with the inner layer via the first and second alignment targets. This avoids alignment anomalies caused by deformation of the alignment holes due to uneven copper thickness. The 3mm vertical spacing difference between the third and fourth targets serves as a foolproof feature, providing a unique directional marker for the entire alignment structure. This special spacing difference allows operators to easily determine the correct installation direction and position, avoiding alignment errors and ensuring production process stability and consistency. This significantly reduces product scrap due to alignment anomalies, thereby significantly improving the yield rate of AI computing power card HDI boards and reducing production costs. Attached Figure Description

[0020] Figure 1 An example of an AI computing power card HDI board structure Figure 2 This is a schematic diagram of four first alignment target sites in one embodiment.

[0021] The following are the diagram labels: 1. Outer layer; 2. Inner layer; 21. First target position; 22. Second target position; 23. Third target position; 24. Fourth target position. Detailed Implementation

[0022] The alignment structure of an AI computing power card HDI board according to this utility model will be described in further detail below with reference to specific embodiments and accompanying drawings.

[0023] like Figure 1 and Figure 2As shown in a preferred embodiment, the alignment structure of the AI ​​computing power card HDI board of this utility model includes an inner layer 2 and an outer layer 1. The four corners of the inner layer 2 are provided with four first alignment targets, namely a first target 21, a second target 22, a third target 23 and a fourth target 24. The first target 21 and the second target 22 are arranged coaxially along the horizontal direction. The third target 23 is aligned with the first target 21 along the vertical direction. The fourth target 24 is aligned with the second target 22 along the vertical direction. The vertical distance difference between the third target 23 and the fourth target 24 is 3mm. The outer layer 1 is provided with four second alignment targets that are in the same position as the first alignment targets. The four first alignment targets of inner layer 2 form a fixed reference coordinate system. The first target 21 and the second target 22 are arranged horizontally and coaxially. The third target 23 is vertically aligned with the first target 21, and the fourth target 24 is vertically aligned with the second target 22. This arrangement constructs a regular framework. Through a high-precision alignment device, the relative positional relationship between the first alignment target and the second alignment target can be detected. Once a deviation is detected, the device can make precise adjustments based on the positional information of the first alignment target and the second alignment target, so that outer layer 1 is accurately aligned with inner layer 2, avoiding alignment abnormalities caused by deformation of alignment holes due to uneven copper thickness.

[0024] In addition, the 3mm vertical spacing difference between the third target position 23 and the fourth target position 24 serves as a foolproof feature, providing a unique directional marker for the entire alignment structure. Through this special spacing difference, operators can easily determine the correct installation direction and position, avoiding alignment errors, thereby ensuring the stability and consistency of the production process, greatly reducing product scrap due to alignment abnormalities, and thus significantly improving the production yield of AI computing power card HDI boards and reducing production costs.

[0025] In this embodiment, the horizontal distance X1 between the first target position 21 and the second target position 22 is 475.6 mm, the horizontal distance X2 between the third target position 23 and the fourth target position 24 is 475.6 mm, the vertical distance Y1 between the first target position 21 and the third target position 23 is 491.92 mm, the vertical distance Y2 between the second target position 22 and the fourth target position 24 is 488.92 mm, the vertical distance difference Y1-Y2 between the third target position 23 and the fourth target position 24 is 3 mm, and the fourth target position 24 serves as a foolproof structure.

[0026] In some embodiments, when the via ring of the HDI board is smaller than that of the blind via, four first alignment targets are set on all layers of the inner layer 2. When the outer layer 1 is aligned with the inner layer 2, both vias and blind vias need to be aligned simultaneously. When the via ring is smaller than that of the blind via, the via may be in a more critical position in the overall circuit layout, responsible for the transmission of some key signals. Since the via runs through the entire HDI board and connects multiple inner layers 2, its positional accuracy directly affects the stability and accuracy of signal transmission between different layers. Setting four first alignment targets on all layers of the inner layer 2 can provide a precise positional reference for the vias of each layer, ensuring that the vias of each layer are accurately aligned in space, so that signals can be smoothly transmitted between different layers through the vias, reducing signal loss and interference.

[0027] In some embodiments, when the blind via ring of the HDI board is smaller than that of the through via, and the outer layer 1 consists of layers L1 and LN, the four first alignment targets are only set in layers L2 and LN-1 of the inner layer 2. Alignment of the outer layer 1 with the inner layer 2 requires simultaneous alignment of through vias and blind vias. When the blind via ring of the HDI board is smaller than that of the through via, blind via alignment is prioritized. Layers L2 and LN-1 are located close to the two outer layers L1 and LN, respectively. Selecting layers L2 and LN-1 as alignment targets optimizes production efficiency and cost while meeting the blind via alignment accuracy requirements. These two layers reflect the main positional relationships and changing trends of blind vias within the entire inner layer 2 structure. Precise alignment of these two layers of blind vias can, to a certain extent, ensure the alignment accuracy of blind vias in other layers, avoiding unnecessary resource waste.

[0028] like Figure 2 As shown, in some embodiments, the four first alignment targets are circular structures with a target diameter of 137 mil. The 137 mil diameter of the circular target is a moderate size, allowing for clearer and more accurate identification of the target during manufacturing, whether by manual visual inspection or automated optical inspection equipment. The circular structure is isotropic, eliminating directional issues, and is easier for the inspection system to quickly locate and identify compared to other irregularly shaped targets. This improves the accuracy of alignment between the outer layer 1 and the inner layer 2, reducing electrical connection problems caused by misalignment. Furthermore, the circular structure is relatively simple and easier to implement using common photolithography and etching processes, ensuring the dimensional accuracy and shape consistency of the target.

[0029] As shown in the figure, in some embodiments, the diameter of the second alignment target is not less than the diameter of the first alignment target. During the alignment of the outer layer 1, the optical device needs to simultaneously capture the first alignment target of the inner layer 2 and the second alignment target of the outer layer 1. A slightly larger second alignment target of the outer layer 1 can provide the device with more capture tolerance and avoid alignment failure due to slight offset. In the multilayer lamination process, there are slight offsets in each layer. Appropriately enlarging the diameter of the second alignment target can absorb the accumulated errors of the previous process and ensure the final interlayer alignment accuracy.

[0030] In some embodiments, the concentricity error between the second alignment target and the first alignment target is between -1 mil and 1 mil. This extremely small concentricity error range ensures high precision in the alignment process between the outer layer 1 and the inner layer 2. In HDI board manufacturing, precise alignment of blind vias and through-holes is crucial. The first and second alignment targets serve as positioning references, and their high-precision concentricity control allows for accurate alignment of blind vias and through-holes. This helps avoid problems such as poor circuit connections, short circuits, or open circuits caused by misalignment, improving the yield rate in the production process and reducing scrap costs due to alignment errors.

[0031] In some embodiments, the copper thickness uniformity error of the four first alignment targets and the four second alignment targets is between -1.5 μm and 1.5 μm. When the copper thickness uniformity error is strictly controlled within -1.5 μm to 1.5 μm, the surface flatness of the first and second alignment targets is higher. In the optical recognition system, the uniform copper thickness allows the targets to reflect clearer and more stable images. This helps the optical detection equipment to more accurately capture the edge and center positions of the first alignment targets and the four second alignment targets, reducing image blurring or distortion caused by uneven copper thickness. This improves the accuracy of position recognition of the first alignment targets and the four second alignment targets during the alignment process, providing a foundation for high-precision alignment.

[0032] This invention relates to the working principle and process of an AI computing power card HDI board alignment structure. Using a high-precision alignment device, the relative positional relationship between the first alignment target on the inner layer 2 and the second alignment target on the outer layer 1 can be detected. Once a deviation is detected, the device can make precise adjustments based on the positional information of the first and second alignment targets, ensuring that the outer layer 1 is accurately aligned with the inner layer 2. This avoids alignment abnormalities caused by deformation of the alignment holes due to uneven copper thickness. Furthermore, the 3mm vertical spacing difference between the third target 23 and the fourth target 24 serves as a foolproof feature, providing a unique directional marker for the entire alignment structure. Through this special spacing difference, operators can easily determine the correct installation direction and position, avoiding alignment errors.

[0033] In the description of this utility model, it should be understood that terms such as "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0034] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0035] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0036] Although the description of this utility model has been given in conjunction with the specific embodiments described above, it is obvious to those skilled in the art that many substitutions, modifications, and variations can be made based on the above description. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. An alignment structure for an AI computing power card HDI board, characterized in that, The device includes an inner layer and an outer layer. The inner layer has four first alignment target positions at its four corners. The four first alignment target positions are a first target position, a second target position, a third target position, and a fourth target position. The first target position and the second target position are arranged coaxially along the horizontal direction. The third target position is aligned with the first target position along the vertical direction. The fourth target position is aligned with the second target position along the vertical direction. The vertical distance between the third target position and the fourth target position is 3mm. The outer layer has four second alignment target positions that are in the same position as the first alignment target positions.

2. The alignment structure of the AI ​​computing power card HDI board according to claim 1, characterized in that, When the via ring of the HDI board is smaller than that of the blind via, the four first alignment targets are set in all layers of the inner layer.

3. The alignment structure of the AI ​​computing power card HDI board according to claim 1, characterized in that, When the blind via ring of the HDI board is smaller than the through via, and the outer layer is L1 and LN layers, the four first alignment targets are only set in the inner layer L2 and LN-1 layers.

4. The alignment structure of the AI ​​computing power card HDI board according to claim 1, characterized in that, The four first alignment targets are circular structures with a target diameter of 137 mil.

5. The alignment structure of the AI ​​computing power card HDI board according to claim 1, characterized in that, The target diameter of the second alignment target is not less than the target diameter of the first alignment target.

6. The alignment structure of the AI ​​computing power card HDI board according to claim 1, characterized in that, The concentricity error between the second and first aligned target positions is between -1 mil and 1 mil.

7. The alignment structure of the AI ​​computing power card HDI board according to claim 1, characterized in that, The copper thickness uniformity error of the four first alignment target sites and the four second alignment target sites is between -1.5μm and 1.5μm.

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