Two-step depth control processing method for AI computing card ladder gold fingers

Abstract

The application discloses a two-step depth control processing method for AI computing power card ladder golden fingers, comprising the following steps: providing an N plate and an M plate, the surface of the M plate is formed with ladder golden fingers; pre-slotting processing is performed on the predetermined area of the N plate to form a pre-slot, the depth of the pre-slot is smaller than the thickness of the N plate, and the pre-slotting processing takes the preset alignment mark on the N plate as a positioning reference; the N plate and the M plate are pressed together, so that the ladder golden fingers of the M plate are located below the pre-slot area of the N plate; and the formed plate after pressing is subjected to forming and uncovering processing, the depth control uncovering is performed along the same path as the pre-slot, the forming and uncovering processing is positioned by taking the positioning reference associated with the preset alignment mark as the positioning reference, the depth of the forming and uncovering is matched with the depth of the pre-slot, and the thickness of the remaining material removed by the final uncovering is smaller than the minimum depth control capability of the forming and uncovering equipment. Through twice processing cooperation, the limitation of the minimum depth control capability of the equipment is broken, and high-reliability uncovering processing of the ultra-thin interlayer structure is realized.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and more specifically, to a two-step deep processing method for the stepped gold fingers of an AI computing power card. Background Technology

[0002] As the demand for AI computing power continues to increase, the design of AI computing cards is becoming increasingly complex. Due to the limitations of the PCIe interface standard's board thickness (1.57mm) and objective constraints on chip supply, the industry generally adopts an add-on design to meet computing power requirements. This involves adding an extra circuit layer above the standard thickness gold finger area to form a stepped gold finger structure.

[0003] In the traditional manufacturing process of stepped gold fingers for through-hole plates, an N+M stacked design is typically used. Specifically, the stepped gold fingers are first fabricated at the sub-plate stage, and high-temperature adhesive tape is applied to the surface of the stepped gold fingers. Then, they are pressed together with the outer plate. After pressing, a forming device is used for blind unpacking to remove the covering material on top of the stepped gold fingers, thereby exposing the gold fingers.

[0004] However, the aforementioned traditional processes have significant limitations in processing capability. The minimum controllable cutting depth of blind-fishing decapping equipment is typically around 4 mil, while the thinnest available high-temperature tape is generally about 3 mil. To meet the processing capability requirements of the equipment, the dielectric layer (usually a prepreg) between the N+M stacks must reach a certain thickness, for example, using two 1080 or 1078 prepregs laminated together to form a thickness of approximately 6 mil. When the customer requires a thickness between N+M layers of less than 4 mil, the traditional process cannot be implemented. If the decapping depth is too deep, it will damage the underlying stepped gold fingers; if the decapping depth is too shallow, the covering material cannot be completely removed, resulting in prepreg or substrate material residue on the gold finger surface. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: A two-step depth-controlled machining method for stepped gold fingers on an AI computing power card includes the following steps: providing an N-plate and an M-plate, wherein stepped gold fingers are formed on the surface of the M-plate; pre-grooving a predetermined area of ​​the N-plate to form a pre-groove, the depth of which is less than the thickness of the N-plate, and the pre-grooving is based on a preset alignment mark on the N-plate as a positioning reference; pressing the N-plate and the M-plate together so that the stepped gold fingers of the M-plate are located below the pre-grooved area of ​​the N-plate; and performing a forming and opening process on the pressed plate, performing depth-controlled opening along the same path as the pre-grooving, the forming and opening process being positioned based on a positioning reference associated with the preset alignment mark, and the depth of the forming and opening matching the depth of the pre-grooving, so that the thickness of the remaining material removed after the final opening is less than the minimum depth control capability of the forming and opening equipment.

[0006] This technical solution breaks down a single high-precision cap opening process into two steps. By using the same alignment mark as a reference, the two processing paths are ensured to be precisely aligned. Through deep fitting, the final cap opening requires the removal of only an extremely thin layer of material, less than the minimum depth control capability of the equipment. This allows for highly reliable cap opening processing of ultra-thin interlayer structures without upgrading the equipment.

[0007] In a further proposed solution, the pre-grooving process employs controlled depth milling.

[0008] This technical solution uses controlled depth milling for pre-grooving, which can utilize existing machining equipment and helps reduce the cost of process implementation.

[0009] In a further embodiment, the pre-grooving process adopts a laser-controlled depth processing method, which includes: forming multiple laser processing holes along a preset path, with adjacent laser processing holes partially overlapping to form a continuous pre-grooving.

[0010] This technical solution uses laser processing for pre-grooving, and forms a continuous groove structure by partially overlapping adjacent laser holes, which is beneficial for achieving high-precision, narrow-path grooving processing.

[0011] In a further embodiment, the depth of the pre-grooving is 40% to 60% of the thickness of the N-plate.

[0012] This technical solution controls the pre-grooving depth to between 40% and 60% of the N-plate thickness, which can significantly reduce the amount of material removed during the final opening while retaining sufficient thickness to maintain the structural strength of the N-plate during the pressing process.

[0013] In a further proposed solution, the depth of the forming and opening process is determined based on the actual thickness of the N plate, the thickness of the dielectric layer between the N plate and the M plate, and the preset safety distance.

[0014] This technical solution dynamically calculates the opening depth based on the actual thickness of the sheet material, which helps to compensate for manufacturing tolerances and ensures that a safe distance is always maintained between the bottom surface of the opening and the gold fingers.

[0015] In a further embodiment, before the N board and the M board are pressed together, a layer of protective tape is applied to the surface of the stepped gold fingers of the M board.

[0016] This technical solution involves attaching protective tape to the surface of the gold fingers before lamination, which can effectively prevent molten resin from contaminating the surface of the gold fingers during the lamination process.

[0017] In a further proposed solution, the protective tape is removed after the molding and opening process.

[0018] This technical solution allows the stepped gold fingers to be fully exposed after the protective tape is removed upon opening the cover, while also removing residual debris to obtain a clean gold finger surface.

[0019] In a further solution, the preset alignment mark is an inner alignment target, and the positioning reference associated with the preset alignment mark is an outer positioning hole formed on the panel after lamination based on the inner alignment target.

[0020] This technical solution uses the inner target as the position reference, drills the outer positioning hole after X-ray identification, and realizes the accurate transfer of the two processing coordinate systems.

[0021] In a further solution, the depth of the forming and opening process is set as: T_final = T_N + T_pp - D_safe, where T_final is the forming and opening depth, T_N is the actual thickness of the N board, T_pp is the thickness of the dielectric layer between the N board and the M board, and D_safe is the preset safety distance.

[0022] This technical solution defines the depth calculation method in the form of a formula, associates the depth value with the measured board thickness, and is conducive to the standardization and repeatability of process parameters.

[0023] In a further solution, the depth T_pre of the pre-slotting and the depth T_final of the forming and opening satisfy the relationship: T_pre + D_safe < T_N + T_pp, and T_final - T_pre is less than the minimum depth control ability of the forming and opening equipment.

[0024] This technical solution limits the coordination relationship between the two depths through inequalities, ensures that the pre-slotting does not damage the gold fingers, and the final opening removal amount is less than the minimum depth control ability of the equipment, realizing the processability of the ultra-thin interlayer structure.

[0025] The beneficial effects of the present invention compared with the prior art are as follows: By decomposing the one-time high-precision depth control opening into two processes of pre-slotting and forming and opening, and ensuring the accurate alignment of the paths of the two processes with the same alignment mark system, and at the same time, through the depth coordination design, the final opening only needs to remove an extremely thin remaining material layer, and the thickness of this thin layer is less than the minimum controllable cutting ability of the forming and opening equipment, thus breaking through the limitation of the equipment's own process ability, and realizing the technical effect of being able to expose the stepped gold fingers without damage when the thickness of the interlayer dielectric layer between the N board and the M board is less than the minimum depth control ability of the equipment. This method does not require upgrading the processing equipment, and only through the optimization of the process flow, it can achieve the reliable processing of the ultra-thin interlayer structure, significantly improving the product yield and design flexibility, and reducing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0027] Figure 1 This is a process flow diagram of an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the N+M stacked structure design according to an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the laser drilling program path and the stepped gold finger area in an embodiment of the present invention.

[0030] Figure 4 This is a schematic diagram of the laser aperture overlap design according to an embodiment of the present invention.

[0031] Figure 5 This is a schematic diagram of the pre-grooving process in an embodiment of the present invention.

[0032] Figure 6 This is a schematic diagram of the laminated plate structure according to an embodiment of the present invention.

[0033] Figure 7 This is a schematic diagram of the molding and opening path according to an embodiment of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Similar reference numerals and letters in the drawings indicate similar items. Once an item is defined in one drawing, it does not need to be defined again in subsequent drawings. The terms "upper," "lower," "left," "right," "vertical," "horizontal," etc., indicate the orientation or positional relationship based on the orientation shown in the drawings or conventional understanding, and are used only for description, not to indicate or imply that the device must have a specific orientation. In the absence of conflict, the embodiments and features of this application can be combined with each other.

[0035] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0036] I. Overall Process Overview This embodiment uses a 6+12 layer N+M stacked structure for stepped gold fingers as an example. Layers L7 to L18 of the M board constitute the stepped gold finger portion, with a designed thickness of 1.57mm to match the PCIe slot standard. Layers L1 to L6 of the N board are additional layers, their thickness determined according to design requirements. The N board and M board are bonded together using a prepreg layer.

[0037] The entire processing flow is divided into the following stages: N-plate pre-grooving, M-plate stepped gold finger processing, N-plate and M-plate lamination, outer layer processing, and forming and opening processing. Among these, the N-plate pre-grooving and forming and opening processing are the core improvements of this invention.

[0038] like Figure 2 As shown, sub-plates L1-6 and L7-18 are processed separately and then pressed together to form an integral plate.

[0039] II. N-plate pre-grooving processing After the standard process of lamination, drilling, electroplating, and outer layer patterning is completed for layers L1 to L6 of the N board, the board thickness is approximately 0.65mm. Before proceeding to the outer layer lamination process, an additional pre-grooving process is added.

[0040] The purpose of pre-grooving is to remove some material from the area above the stepped gold fingers on the inner side of the N-plate (L6 layer surface) to facilitate subsequent molding and capping. The path of the pre-grooving is exactly the same as the area that needs to be capped in the end, namely the rectangular area above the stepped gold fingers.

[0041] Regarding the establishment of positioning references, during the inner layer pattern fabrication stage of the N-board, inner layer alignment targets have already been created at the four corners of the board edge. These targets typically use copper cross patterns or concentric ring patterns, with a positional accuracy of ±0.025mm. Before processing, the pre-grooving equipment (whether a laser drilling machine or a depth-controlled milling machine) first identifies these inner layer targets through an optical system and automatically corrects the processing coordinate system based on the actual position of the targets, ensuring the positioning accuracy of the pre-grooving path relative to the N-board itself.

[0042] Regarding the selection of the pre-grooving depth, the core design idea of ​​this implementation method is: by pre-grooving, most of the material is removed in advance, so that when the cover is finally opened, the equipment only needs to remove an extremely thin layer of material. The thickness of this thin layer of material should be less than the minimum controllable cutting depth of the forming equipment.

[0043] The minimum depth control capability of the forming and opening equipment refers to the minimum cutting depth that the equipment can accurately control under stable processing conditions. It is usually determined by factors such as the accuracy of the equipment spindle, the rigidity of the tool, and the response speed of the control system. For example, the minimum depth control capability of the equipment used in this embodiment is 0.10mm (about 4mil).

[0044] Taking the minimum depth control ability of the equipment as 0.10 mm as an example, the final thickness removed during the opening of the cover should be controlled below 0.10 mm. Assuming the thickness of the N board \(T_N\) is 0.65 mm, the thickness of the interlayer dielectric layer \(T_{pp}\) is 0.075 mm, the thickness of the protective tape \(T_{tape}\) is 0.075 mm, and the preset safety distance \(D_{safe}\) is 0.10 mm, then the total thickness of the material that needs to be removed during the final opening of the cover is \((T_N + T_{pp}+T_{tape}-D_{safe}) = 0.65 + 0.075+0.075 - 0.10 = 0.70\) mm. In order to achieve the goal that the final thickness removed during the opening of the cover is less than 0.10 mm, the pre-grooving depth \(T_{pre}\) should be greater than 0.60 mm.

[0045] In actual production, the pre-grooving depth can be adjusted according to the specific board thickness and equipment capabilities to ensure that \((T_N + T_{pp}+T_{tape}-D_{safe}-T_{pre})<C_{min}\), where \(C_{min}\) is the minimum depth control ability of the equipment.

[0046] As another optional depth design method, the pre-grooving depth can also be selected to be 40% to 60% of the thickness of the N board. Although this design may not be able to reduce the final thickness removed during the opening of the cover below the equipment capabilities, by decomposing a single deep opening into two shallower openings, it is still possible to reduce the difficulty and risk of single processing and improve the quality of the opening of the cover. Designers can select a suitable depth range according to the specific product requirements and equipment capabilities.

[0047] Regarding the implementation method of pre-grooving, as a specific implementation method, laser-controlled deep processing can be used for pre-grooving. As Figure 3 shown, the laser drilling program path is designed and manufactured according to the path of the formed opening of the cover. The stepped gold finger area is within the green frame line in the figure. The laser processing equipment emits a laser beam according to the preset path to form a series of laser processing holes on the surface of the L6 layer of the N board. As Figure 4 shown, the laser holes adopt an overlapping design. The diameter of the laser hole is 0.125 mm (about 5 mil), the center distance between adjacent laser holes is 0.075 mm (about 3 mil), and an overlapping area of about 0.05 mm is formed between adjacent holes, thus forming a continuous pre-groove. The depth control accuracy of laser processing can reach ±0.025 mm, which can accurately achieve the required depth requirements. The thermal influence area of laser processing is small and will not damage the materials around the bottom of the groove. During processing, the N boards are placed one by one in a stack with the L6 layer facing up. As Figure 5 shown, the L6 layer is the red pattern, and the green frame line is the cutting position. Cutting is performed from the L6 layer towards the L1 layer direction, and the cutting depth is controlled to be 12±3 mil (about 0.30±0.075 mm).

[0048] As an alternative implementation, controlled depth milling can be used for pre-grooving. Controlled depth milling equipment uses a micro-milling cutter, which can form a continuous groove structure in a single pass along a preset path. The depth control accuracy of controlled depth milling is approximately ±0.05mm, and the cost is relatively low, making it suitable for products with less stringent precision requirements. Regardless of the method used, after pre-grooving, the inner layer alignment target on the N-plate is retained as a positional reference for subsequent machining.

[0049] III. M-plate stepped gold finger processing Layers L7 to L18 of the M-plate undergo standard processes including lamination, drilling, electroplating, and outer layer patterning. After forming stepped gold fingers on the L7 layer surface, a high-temperature protective tape is applied to the surface of the stepped gold fingers. This tape is made of a material with excellent temperature resistance and does not adhere to the prepreg resin; its thickness is approximately 0.075 mm. The tape completely covers the stepped gold finger area and is slightly larger than this area to ensure that molten resin does not seep into the gold finger surface during lamination.

[0050] IV. Pressing N-plate and M-plate together After pre-grooving, the N-board is stacked with the M-board after adhesive tape is applied, with layer L6 of the N-board facing layer L7 of the M-board, so that the pre-grooved area of ​​the N-board is aligned with the stepped gold finger area of ​​the M-board. A prepreg is placed between the two layers as an adhesive medium. In this embodiment, to meet the customer's strict requirements for board thickness, only a single 1080 prepreg is used, resulting in a thickness of approximately 0.075 mm after lamination.

[0051] After stacking, the plates are pressed together using a pinlam method. The pressing equipment uses positioning pins that engage with positioning holes on the plates to ensure precise relative positioning of the N and M plates. Under high temperature and pressure, the prepreg melts and solidifies, firmly bonding the N and M plates together. Because high-temperature tape is applied to the surface of the stepped gold fingers, the molten resin is blocked by the tape and will not contaminate the gold finger surface.

[0052] After lamination, a new positioning reference needs to be established for subsequent processing. At this point, the inner target is covered by the outer copper foil and cannot be directly observed. Therefore, an X-ray drilling machine is needed to penetrate the outer copper foil to identify the position of the inner target, and then, based on the coordinates of the inner target, drill outer positioning holes that penetrate the entire board. These outer positioning holes have a precise spatial correspondence with the inner target, becoming the positioning reference for subsequent molding and opening processes.

[0053] like Figure 6 As shown, in the pressed sheet, the pre-grooving extends inward from the inside of the N plate, and after the cover is opened, it will cut in from the other side along the same path.

[0054] V. Outer Layer Processing After lamination, the plates undergo routine processes such as outer layer patterning, solder masking, and surface treatment. These processes are all performed using the outer layer positioning holes drilled by X-ray as a reference to ensure the positional accuracy of the outer layer pattern and the inner layer structure.

[0055] VI. Molding and opening process After the outer layer processing is completed, the molding and capping process begins. The purpose of this process is to remove the ineffective area above the stepped gold fingers and expose the covered gold fingers.

[0056] Regarding the positioning method, the pressed sheet is placed on the worktable of the forming and opening equipment, and positioned using the outer layer positioning holes as a reference. For example... Figure 7 As shown, the forming and opening path is outlined in green and is completely consistent with the pre-grooving path. Since the outer positioning holes are drilled based on the inner target, and the pre-grooving process is also based on the inner target, the processing coordinate system of the forming and opening and the processing coordinate system of the pre-grooving are accurately transferred, and their processing paths can be ensured to coincide in space.

[0057] Regarding depth control, the forming opening depth needs to be dynamically calculated based on the actual plate thickness. The operator first measures the actual thickness T_N of the N-plate (considering thickness variations after lamination) and the actual thickness T_pp of the interlayer dielectric layer, and sets a safety distance D_safe (e.g., 0.10mm). The formula for calculating the forming opening depth T_final is: T_final = T_N + T_pp - D_safe.

[0058] Taking the aforementioned design as an example, if the pre-grooving depth T_pre is set to 0.62mm, then the total thickness that needs to be removed when finally opening the cover (from the L1 surface to the upper surface of the tape) is T_N+T_pp+T_tape-D_safe=0.65+0.075+0.075-0.10=0.70mm. Since 0.62mm has been removed by pre-grooving, the actual remaining material thickness that the equipment needs to remove is 0.70-0.62=0.08mm.

[0059] The above calculations show that, after adopting this method, the final thickness of the remaining material actually removed by the opening device is 0.08 mm, which is less than the minimum depth control capability of the device (0.10 mm), thus achieving the design objective of this invention.

[0060] Regarding the capping process, the capping equipment performs controlled-depth milling according to a preset path, which is completely consistent with the pre-grooving path. After capping is completed, the invalid area covering the stepped gold fingers (including the remaining part of the N board, the interlayer dielectric layer, and part of the adhesive tape) is separated from the board body.

[0061] 7. Remove the protective tape After opening the cover, the operator uses tweezers or a vacuum pen to peel off the high-temperature adhesive tape covering the stepped gold fingers, along with any adhering debris. Since the tape is not bonded to the gold fingers, the removal process does not damage the gold finger surface. After removing the tape, the stepped gold fingers are fully exposed, with a clean surface free of residue, ready for subsequent testing or assembly processes.

[0062] VIII. Explanation of Alternative Implementation Plans In addition to using a combination of an inner target and an outer positioning hole, the following alternative methods can be used to achieve the positioning reference: During the pre-grooving of the N-plate, a positioning hole penetrating the N-plate is simultaneously machined. After lamination, this positioning hole is covered by the outer material, and its position is identified by X-ray as a reference for subsequent processing. Alternatively, alignment marks can be made on both the N-plate and the M-plate. After lamination, X-rays are used to simultaneously identify the two layers of marks and calculate the relative positional deviation, which is then compensated for in the machining program. Both methods can achieve accurate transfer of the coordinate system between the two machining processes.

[0063] In addition to the formula mentioned above, the calculation method for the forming opening depth can also be done by using a lookup table or empirical formula. The depth value can be preset according to factors such as the batch of sheet material and the condition of the equipment, and the adjustment can be made by real-time monitoring of the spindle load or processing sound during the processing.

[0064] Regarding the timing of removing the protective tape, in addition to removing it after opening the lid, it can also fall off naturally during the opening process as the invalid area separates, in which case there is no need to set a separate removal step.

[0065] IX. Quantitative Explanation of Key Process Parameters To enable those skilled in the art to better understand the deep-fit ​​design concept of this invention, a set of specific numerical examples are provided below.

[0066] Design goal: The minimum depth control capability of the forming and opening device is C_min = 0.10 mm (approximately 4 mil). The thickness of the remaining material removed after final opening should be less than 0.10 mm.

[0067] Known parameters: The total thickness of plate N is T_N = 0.65mm. Interlayer dielectric layer thickness T_pp = 0.075 mm The thickness of the protective tape, T_tape, is 0.075mm. Preset safe distance D_safe=0.10mm calculate: The total thickness of material to be removed upon opening the cover (if no pre-grooving is performed) is: T_N+T_pp+T_tape-D_safe=0.65+0.075+0.075-0.10=0.70mm.

[0068] To achieve the goal of removing a thickness of less than 0.10mm after final opening, the pre-grooving depth T_pre should satisfy: 0.70-T_pre<0.10, that is, T_pre>0.60mm.

[0069] Therefore, if the pre-grooving depth is set to 0.62mm, the actual thickness that the opening equipment needs to remove is 0.70-0.62=0.08mm, which is less than the equipment's minimum depth control capability of 0.10mm.

[0070] The above calculations show that, after adopting this method, the final thickness of the remaining material actually removed by the opening device is 0.08 mm, which is less than the minimum depth control capability of the device (0.10 mm), thus achieving the design objective of this invention.

[0071] The numerical examples above are only for illustrating the design principles. In actual production, the values ​​of each parameter can be adjusted according to the specific plate thickness, equipment capacity, and process requirements.

[0072] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A two-step deep processing method for the stepped gold fingers of an AI computing power card, characterized in that, The steps include: Providing an N board and an M board, with stepped gold fingers formed on the surface of the M board (S1); Performing pre-grooving machining on a predetermined area of the N board to form a pre-groove, the depth of the pre-groove being less than the thickness of the N board, and the pre-grooving machining being positioned based on a preset alignment mark on the N board (S2); Pressing the N board and the M board together so that the stepped gold fingers of the M board are located below the area corresponding to the pre-groove area of the N board (S3); Performing forming and opening processing on the pressed board member, performing depth-controlled opening along the same path as the pre-groove, the forming and opening processing being positioned based on an alignment reference associated with the preset alignment mark, and the depth of the forming and opening being coordinated with the depth of the pre-groove so that the remaining material thickness removed by the final opening is less than the minimum depth control ability of the forming and opening device (S4).

2. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 1, characterized in that, The pre-grooving machining adopts a depth-controlled milling machining method.

3. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 1, characterized in that, The pre-grooving machining adopts a laser depth-controlled machining method, including: forming a plurality of laser machining holes along a preset path, with adjacent laser machining holes partially overlapping to form a continuous pre-groove.

4. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 1, characterized in that, The depth of the pre-groove is 40% to 60% of the thickness of the N board.

5. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 1, characterized in that, The depth of the forming and opening processing is determined based on the actual thickness of the N board, the thickness of the dielectric layer between the N board and the M board, and a preset safety distance.

6. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 1, characterized in that, Before pressing the N board and the M board together, a layer of protective tape is attached to the surface of the stepped gold fingers of the M board.

7. The two-step depth control processing method for the AI ​​computing power card stepped gold finger according to claim 6, characterized in that, After the forming and opening processing, the protective tape is removed.

8. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 1, characterized in that, The preset alignment mark is an inner-layer alignment target, and the alignment reference associated with the preset alignment mark is an outer-layer alignment hole formed on the pressed board member based on the inner-layer alignment target.

9. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 1, characterized in that, The depth of the forming and opening processing is set as: T_final = T_N + T_pp - D_safe, where T_final is the depth of the forming and opening, T_N is the actual thickness of the N board, T_pp is the thickness of the dielectric layer between the N board and the M board, and D_safe is the preset safety distance.

10. The two-step deep processing method for the AI ​​computing power card stepped gold finger according to claim 9, characterized in that, The depth T_pre of the pre-groove and the depth T_final of the forming and opening satisfy the relationship: T_pre + D_safe < T_N + T_pp, and T_final - T_pre is less than the minimum depth control ability of the forming and opening device.

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