Packaging substrate processing method and packaging substrate

Abstract

The embodiment of the invention provides a packaging substrate processing method and a packaging substrate. The processing method comprises the following steps: processing a blind groove in the packaging substrate; a plurality of strip-shaped dry films distributed at intervals are formed in the blind groove, and a plurality of first to-be-plated areas are formed among the strip-shaped dry films at intervals; first electroplating is carried out, and a plurality of first metal filling structures are formed in the first to-be-plated areas; the plurality of strip-shaped dry films are removed, dry films are formed on the surfaces of the plurality of first metal filling structures, and a plurality of spaced second to-be-plated areas are formed among the plurality of first metal filling structures; and second electroplating is carried out, multiple second metal filling structures are formed in the multiple second to-be-plated areas, and the multiple second metal filling structures are combined with the multiple first metal filling structures. According to the processing method of the packaging substrate, high-quality electroplating filling of a large-size blind groove can be realized, and the problem of center sinking of electroplating filling of the large-size blind groove is solved.

Description

Technical Field

[0001] This application relates to the field of packaging substrate technology, and in particular to a packaging substrate processing method and a packaging substrate. Background Technology

[0002] With the development of high-power AI chips, GPU chips, electric vehicle power devices, 5G base station power modules, and other products, packaging substrates need to improve their current conduction and thermal management performance to meet product demands. For example, in scenarios such as hotspot areas, heat sink connection areas, and high-current pad areas directly under the chip, blind trenches with lengths and widths reaching the millimeter level need to be fabricated, and metal needs to be filled within the blind trenches to achieve electrical connection or heat dissipation functions.

[0003] In traditional packaging substrates, the dimensions (length and width) of blind vias (or blind trenches) are typically less than 100 μm. Therefore, for packaging substrates, blind trenches with both length and width in the millimeter range are considered large-sized. For traditional electroplating processes used for small-sized blind trenches, current lines are severely concentrated at the trench edges, resulting in extremely low metal deposition rates in the central region. This leads to severe central depressions after filling large-sized blind trenches with metal, with depression depths reaching 10-20 μm, failing to meet the flatness requirements of the packaging substrate. Even using the most advanced electroplating additive systems, it is difficult to achieve depression-free filling for blind trenches with widths exceeding 150 μm, and experimental results for millimeter-sized blind trenches show no effective filling effect whatsoever.

[0004] Currently, there is no effective process to achieve high-quality electroplating filling for blind slots with length and width both in the millimeter range. This technological bottleneck has severely restricted the development of high-power packaging products and urgently needs to be improved. Summary of the Invention

[0005] This application provides a packaging substrate processing method and packaging substrate. By virtually dividing the blind trench into multiple first plating areas and multiple second plating areas, and performing a first electroplating and a second electroplating on the multiple first plating areas and multiple second plating areas respectively, high-quality electroplating filling for large-size blind trenches can be achieved, improving the problem of central depression in the electroplating filling of large-size blind trenches.

[0006] This application provides a method for processing a packaging substrate, including: Process blind slots on the packaging substrate; Multiple strip-shaped dry films are formed in the blind groove at intervals, and multiple first areas to be plated are formed between the multiple strip-shaped dry films at intervals. A first electroplating process is performed to form multiple first metal filling structures in the multiple first areas to be plated. Remove the plurality of strip-shaped dry films and form a dry film on the surface of the plurality of first metal filling structures, and form a plurality of second areas to be plated spaced apart between the plurality of first metal filling structures; A second electroplating process is performed to form multiple second metal filling structures in the multiple second areas to be plated, and the multiple second metal filling structures are combined with the multiple first metal filling structures.

[0007] In some embodiments, forming a plurality of spaced-apart strip-shaped dry films within the blind groove includes: A first dry film is attached to the surface of the packaging substrate, and the first dry film partially fills the blind groove; The first dry film is exposed using the first photomask; The first dry film after exposure is developed to remove part of the first dry film, so that multiple strip-shaped dry films are formed in the blind groove.

[0008] In some embodiments, forming a dry film on the surfaces of the plurality of first metal-filled structures includes: A second dry film is attached to the surface of the packaging substrate, and the second dry film covers the surfaces of the plurality of first metal-filled structures. The second dry film is exposed using a second photomask; The exposed second dry film is developed to remove a portion of the second dry film, thereby forming a dry film on the surfaces of the plurality of first metal-filled structures.

[0009] In some embodiments, prior to forming a plurality of spaced-apart strip-shaped dry films within the blind groove, the method further includes: Residual resin on the inner wall of the blind groove is removed by plasma cleaning; A copper seed layer is deposited on the inner wall of the blind tank using a chemical copper plating process.

[0010] In some embodiments, removing the plurality of strip-shaped dry films includes: The multiple strip-shaped dry films were removed using NaOH stripping solution.

[0011] In some embodiments, after the second electroplating, the process further includes: The metal filling layer in the blind slot is brushed using a mechanical brushing machine to make the surface of the metal filling layer flush with the surface of the packaging substrate. The metal filling layer is formed by combining the plurality of second metal filling structures and the plurality of first metal filling structures.

[0012] In some embodiments, processing blind slots on the packaging substrate includes: The packaging substrate is processed using a CO2 laser to form blind grooves on the packaging substrate. The length and width of the blind grooves are both greater than 1 mm, and the direction of the length and the direction of the width are both parallel to the surface of the packaging substrate.

[0013] In some embodiments, the blind groove has a length of 2 mm, a width of 2 mm, and a depth of 50 μm.

[0014] In some embodiments, prior to processing the blind trench on the packaging substrate, the method further includes: Provide core boards; A dielectric layer and copper foil are laminated onto the core board to form a packaging substrate.

[0015] This application also provides a packaging substrate, which is prepared by the processing method of any of the above embodiments.

[0016] The packaging substrate processing method of this application embodiment forms multiple first plating areas by forming multiple strip-shaped dry films in a blind trench. The multiple first plating areas are subjected to a first electroplating to form multiple first metal filling structures. A dry film is formed on the surface of the multiple first metal filling structures to form multiple second plating areas between the multiple first metal filling structures. The multiple second plating areas are subjected to a second electroplating to form multiple second metal filling structures. The multiple second metal filling structures and the multiple first metal filling structures are combined to form a metal filling layer in the blind trench. This method can achieve high-quality electroplating filling for large-size blind trenches and improve the problem of central depression in the electroplating filling of large-size blind trenches. Attached Figure Description

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

[0018] Figure 1 This is a schematic diagram of the first process of the packaging substrate processing method according to an embodiment of this application.

[0019] Figure 2 This is a schematic diagram of a second process for processing a packaging substrate according to an embodiment of this application.

[0020] Figure 3 This is a longitudinal cross-sectional view of the packaging substrate formed by lamination in an embodiment of this application.

[0021] Figure 4 This is a longitudinal cross-sectional view of the packaging substrate after blind slots have been processed according to an embodiment of this application.

[0022] Figure 5 This is a longitudinal cross-sectional view of the packaging substrate after the first dry film has been applied to it, according to an embodiment of this application.

[0023] Figure 6 This is a schematic diagram showing the formation of multiple first plating areas on the packaging substrate according to an embodiment of this application.

[0024] Figure 7 for Figure 6 The top view of the packaging substrate shown.

[0025] Figure 8 This is a schematic diagram of a plurality of first metal filling structures formed on a packaging substrate according to an embodiment of this application.

[0026] Figure 9 for Figure 8 The diagram shows a longitudinal section of the packaging substrate after the first dry film has been removed.

[0027] Figure 10 for Figure 9 The top view of the packaging substrate shown.

[0028] Figure 11 This is a schematic diagram of a plurality of second metal filling structures formed on a packaging substrate according to an embodiment of this application.

[0029] Figure 12 for Figure 11 The top view of the packaging substrate shown.

[0030] Figure 13 This is a schematic longitudinal section of the packaging substrate after brushing, according to an embodiment of this application. Detailed Implementation

[0031] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0032] This application provides a packaging substrate processing method that enables high-quality electroplating filling of large-size blind trenches, improving the problem of center depression during electroplating filling of large-size blind trenches. The packaging substrate prepared by this processing method can be applied to high-power products such as AI chips, GPU chips, electric vehicle power devices, and 5G base station power modules.

[0033] refer to Figure 1 , Figure 1 This is a schematic diagram of a first embodiment of the packaging substrate processing method according to this application. The packaging substrate processing method includes the following steps 11-15: 11. Fabricate blind slots on the packaging substrate; 12. Multiple strip-shaped dry films are formed in the blind tank at intervals, and multiple first areas to be plated are formed between the multiple strip-shaped dry films. 13. Perform the first electroplating to form multiple first metal filling structures in multiple first areas to be plated; 14. Remove multiple strip-shaped dry films and form dry films on the surfaces of multiple first metal-filled structures, forming multiple second plating areas spaced apart between the multiple first metal-filled structures; 15. Perform a second electroplating to form multiple second metal filling structures in multiple second areas to be plated, and combine the multiple second metal filling structures with multiple first metal filling structures.

[0034] In step 11, blind slots are first fabricated on the packaging substrate. In practical applications, blind slots can be fabricated on the packaging substrate using methods such as machining or laser engraving.

[0035] Subsequently, in step 12, multiple strip-shaped dry films are formed at intervals within the blind tank. These strip-shaped dry films mask a portion of the blind tank, exposing an unmasked area, thus creating multiple first areas to be plated between the strip-shaped dry films. These first areas to be plated are the areas not masked by the dry films. It is understood that because the multiple strip-shaped dry films are spaced apart, a first area to be plated can be formed between every two adjacent strip-shaped dry films, resulting in multiple spaced-apart first areas to be plated.

[0036] In step 13, a first electroplating is performed, forming multiple first metal-filled structures in multiple first areas to be plated. It is understandable that because multiple strip-shaped dry films mask parts of the blind tank, the masked parts will not be plated with metal; only the unmasked parts will be plated. Therefore, a first metal-filled structure can be formed in each first area to be plated. In practical applications, the thickness of the first metal-filled structure can be controlled by adjusting parameters such as the current density and plating time during electroplating.

[0037] In step 14, multiple strip-shaped dry films are first removed, for example, using a film-removing solution. Then, a dry film is formed again on the surfaces of the multiple first metal filler structures. The dry film on the surfaces of the first metal filler structures can mask them. Understandably, since the initial multiple first plating areas are spaced apart, the formed multiple first metal filler structures are also spaced apart. Multiple second plating areas can be formed between the multiple first metal filler structures. Specifically, one second plating area can be formed between every two adjacent first metal filler structures.

[0038] In step 15, a second electroplating process is performed to form multiple second metal filler structures in multiple second areas to be plated. It is understandable that because the dry film on the surface of the first metal filler structure masks its surface, the surface of the first metal filler structure will not continue to thicken during the second electroplating process. Instead, the second metal filler structure will gradually form in the unmasked areas, i.e., the second areas to be plated. Furthermore, since the dry film forms on the surface of the first metal filler structure, it only masks the surface and not the sides. Therefore, during the second electroplating process, the second metal filler structure will gradually grow along the sides of the first metal filler structure. Ultimately, the multiple second metal filler structures formed combine with the multiple first metal filler structures to form the metal filler layer within the blind tank.

[0039] The implementation of this application will be described in detail below with reference to specific embodiments. (Reference) Figures 2 to 13 , Figure 2 This is a schematic diagram of the second process of the packaging substrate processing method according to an embodiment of this application. Figures 3-13 This is a schematic diagram showing the structure of the packaging substrate in different states during the processing. The packaging substrate processing method includes the following steps 21-35: 21. Provide core boards; 22. A dielectric layer and copper foil are laminated onto the core board to form a packaging substrate.

[0040] First, an initial packaging substrate is formed through lamination. A core board is provided initially, which serves as a support structure for the packaging substrate. In one example, such as... Figure 3 As shown, the core board may include a substrate layer and a copper layer. In practical applications, the substrate layer can be made of FR-4 material, and its thickness can be 1.0 mm.

[0041] Subsequently, a dielectric layer and copper foil are sequentially deposited on the core board, and the core board, dielectric layer, and copper foil are then laminated together to form a packaging substrate, as shown in the figure. Figure 3 As shown. In practical applications, the dielectric layer can be called prepreg, and its thickness can be 50 μm. The copper foil can be electrolytic copper foil, and its thickness can be 12 μm. The lamination conditions can be set as follows: temperature 175℃, pressure 2.8 MPa, and time 50 min. The encapsulation substrate formed by lamination under the above lamination conditions can achieve an interlayer peel strength of over 0.8 N / mm, meeting the reliability requirements of the encapsulation substrate.

[0042] Subsequently, providing blind slots on the packaging substrate may include the following steps: 23. A CO2 laser is used to process the packaging substrate to form blind trenches on the packaging substrate.

[0043] Among them, CO2 laser drilling technology is used to process blind trenches, such as rectangular blind trenches, on the surface of the packaging substrate. A schematic diagram of the blind trenches after processing is shown below. Figure 4 As shown in the embodiments of this application, the blind slot is a large-sized blind slot, with both its length and width greater than 1 mm. The directions of its length and width are parallel to the surface of the packaging substrate. In some embodiments, the blind slot has a length of 2 mm, a width of 2 mm, and a depth of 50 μm to meet the current conduction or heat dissipation requirements of high-power products.

[0044] Understandably, in practical applications, blind slots can also be formed on the packaging substrate using machining methods. For example, blind slots can be formed by mechanical drilling or mechanical milling.

[0045] Subsequently, metallizing the surface of the blind slot may include the following steps: 24. Use plasma cleaning to remove residual resin from the inner wall of the blind tank; 25. A copper seed layer is deposited on the inner wall of the blind tank using a chemical copper plating process.

[0046] Understandably, during the process of forming blind trenches on the packaging substrate, some materials of the packaging substrate are removed, such as some resin from the substrate layer. In this process, some resin will remain inside the blind trench. To avoid the influence of this residual resin on subsequent processing, plasma cleaning can be used to remove the residual resin from the inner wall of the blind trench, for example, a plasma adhesive removal process can be used to remove the residual resin.

[0047] Subsequently, a copper seed layer is deposited on the inner wall of the blind trench using a chemical electroless copper deposition process, ensuring 100% coverage of the copper seed layer to complete the metallization of the blind trench surface. Figure 4 As shown. In practical applications, the thickness of the copper seed layer can be 1 μm. Understandably, during the deposition process of the copper seed layer, a copper seed layer will also be deposited on the surface of the packaging substrate, slightly increasing the thickness of the copper foil on the surface of the packaging substrate, for example, by 1 μm.

[0048] Subsequently, a dry film is coated onto the surface of the packaging substrate, and the dry film is patterned to form multiple strip-shaped dry films spaced apart within the blind trench. This may include the following steps: 26. A first dry film is attached to the surface of the packaging substrate, and the first dry film partially fills the blind trench; 27. Expose the first dry film using the first photomask; 28. Develop the first dry film after exposure to remove part of the first dry film, so that multiple strip-shaped dry films are formed in the blind groove.

[0049] Among them, such as Figure 5As shown, a first dry film is first laminated onto the surface of the encapsulation substrate. In practical applications, the first dry film can be a 30μm thick photosensitive dry film. A vacuum laminator can be used to laminate the first dry film onto the surface of the encapsulation substrate (including the blind trench area). In one example, the vacuum level of the vacuum laminator is -98kPa. After lamination, the first dry film can be hot-pressed, for example, at a temperature of 80℃ and a pressure of 0.3MPa. After hot pressing, the first dry film and the inner wall of the blind trench are free of bubbles and peeling, ensuring the sealing performance of the mask.

[0050] Subsequently, the first dry film is exposed using a first mask, for example, using a DI exposure machine. The first mask exposes the areas that will be electroplated in the next step, while covering the other areas.

[0051] Subsequently, the exposed first dry film is developed to remove some of it. In one example, a 0.8% sodium carbonate developer can be used for development, with the development process maintained at a temperature of 30°C, a spray pressure of 0.2 MPa, and a time of 90 seconds.

[0052] Understandably, the developing process removes the dry film from the area exposed by the first mask, while retaining the dry film in other areas as a masking layer. This creates multiple strip-shaped dry films spaced apart within the blind trench, achieving a "virtual partitioning" of the blind trench. In other words, multiple strip-shaped dry films form masking areas, and the areas between these strip-shaped dry films form multiple first-stage areas to be plated. Figure 6 and Figure 7 As shown in the figure. In this figure, a first coating area is formed between every two adjacent strip-shaped dry films.

[0053] Subsequently, the first electroplating process may include the following steps: 29. Perform the first electroplating to form multiple first metal filling structures in multiple first areas to be plated.

[0054] In one example, the packaging substrate can be placed in an acidic copper sulfate electroplating solution, with a current density of 1.5 A / dm³. 2 The electroplating time is 75 minutes. Electroplating is performed on multiple first-to-plate areas to fill holes, forming multiple first-metal-filled structures in these areas. Figure 8 As shown.

[0055] Subsequently, dry film peeling is performed to remove multiple strip-shaped dry films within the blind groove. This may include the following steps: 30. Multiple strip-shaped dry films were removed using NaOH stripping solution.

[0056] In one example, an alkaline stripping solution (NaOH) was used, and the process lasted for 8 minutes at a temperature of 55°C and a spray pressure of 0.2 MPa. This stripped the current dry film layer, exposing multiple formed first metal-filled structures and unfilled blind trench areas. Figure 9 and Figure 10 As shown.

[0057] Understandably, during dry film peeling, the entire packaging substrate is treated with an alkaline NaOH peeling solution. Therefore, when removing the multiple strip-shaped dry films within the blind trenches, the dry film on the surface of the packaging substrate is also removed. At this point, the first dry film adhered to the surface of the packaging substrate is completely removed.

[0058] Subsequently, a dry film is again coated onto the surface of the packaging substrate, and the dry film is patterned to form a dry film on the surfaces of the multiple first metal-filled structures. This may include the following steps: 31. A second dry film is attached to the surface of the packaging substrate, and the second dry film covers the surfaces of multiple first metal-filled structures. 32. Expose the second dry film using the second photomask; 33. Develop the exposed second dry film to remove part of the second dry film, so that a dry film is formed on the surface of multiple first metal-filled structures.

[0059] In this process, a second dry film is laminated onto the surface of the packaging substrate. In practical applications, the process of laminating the second dry film can be the same as that of laminating the first dry film. For example, a 30μm thick photosensitive dry film can be used, and a vacuum laminator with a vacuum degree of -98kPa can be used to laminate the second dry film. Hot pressing is then performed at a temperature of 80℃ and a pressure of 0.3MPa.

[0060] Subsequently, the second dry film is exposed using a second mask, for example, using a DI exposure machine. The pattern of the second mask exposes the remaining areas within the blind trench that need to be electroplated (i.e., the areas between the multiple first metal filler structures), while covering other areas, such as the surfaces of the multiple first metal filler structures and the surface of the packaging substrate.

[0061] Subsequently, the exposed second dry film is developed to remove some of it. In practical applications, the development process for the second dry film can be the same as that for the first dry film, for example, using a 0.8% sodium carbonate developer, maintaining a temperature of 30°C, a spray pressure of 0.2 MPa, and a development time of 90 seconds.

[0062] Understandably, the developing process can remove the dry film from the areas exposed by the second mask, while retaining the dry film in other areas as a masking layer, such as retaining the dry film on the surfaces of multiple first metal filler structures as a masking layer. The areas between the multiple first metal filler structures form multiple spaced second areas to be plated. Specifically, one second area to be plated is formed between every two adjacent first metal filler structures.

[0063] Subsequently, a second electroplating process may be performed, which may include the following steps: 34. Perform a second electroplating to form multiple second metal filling structures in multiple second areas to be plated, and combine the multiple second metal filling structures with multiple first metal filling structures.

[0064] The second electroplating process can be the same as the first electroplating process. For example, the packaging substrate can be placed in an acidic copper sulfate electroplating solution, with a current density of 1.5 A / dm³. 2 The electroplating time is 75 minutes. Electroplating fills multiple second areas to be plated, forming multiple second metal filling structures in these areas. Understandably, during the second electroplating process, the second metal filling structures gradually grow along the sides of the first metal filling structures. Eventually, these multiple second metal filling structures combine with the multiple first metal filling structures, alternating sequentially to form the metal filling layer within the blind tank. Figure 11 and Figure 12 As shown.

[0065] Understandably, during the second electroplating process, the current lines are more concentrated at the edge of the first metal filler structure, resulting in faster metal growth at that edge. After the second electroplating is completed, a protrusion will form at the junction of the second and first metal filler structures, such as... Figure 11 As shown.

[0066] Subsequently, the surface of the packaging substrate is smoothed by brushing, which may include the following steps: 35. Use a mechanical brushing machine to brush the metal filling layer in the blind slot so that the surface of the metal filling layer is flush with the surface of the packaging substrate.

[0067] In practical applications, the flatness of the packaging substrate surface is subject to certain requirements. After the second electroplating, the protrusions formed at the junction of the second and first metal filler structures can affect the flatness of the packaging substrate surface. Therefore, a mechanical brushing machine can be used to brush the metal filler layer within the blind trench to remove uneven metal surfaces, making the surface of the metal filler layer flush with the surface of the packaging substrate. Figure 13As shown. In one example, the grinding wheel of the grinding machine is made of nylon with a particle size of 2000 mesh, a grinding pressure of 0.15 MPa, and a speed of 1.2 m / min. In practical applications, after grinding and leveling, the flatness error of the packaged substrate surface can be reduced to less than 3 μm, meeting the flatness requirements.

[0068] The packaging substrate processing method of this application embodiment forms multiple first plating areas by forming multiple strip-shaped dry films in a blind trench. The multiple first plating areas are subjected to a first electroplating to form multiple first metal filling structures. A dry film is formed on the surface of the multiple first metal filling structures to form multiple second plating areas between the multiple first metal filling structures. The multiple second plating areas are subjected to a second electroplating to form multiple second metal filling structures. The multiple second metal filling structures and the multiple first metal filling structures are combined to form a metal filling layer in the blind trench. This method can achieve high-quality electroplating filling for large-size blind trenches and improve the problem of central depression in the electroplating filling of large-size blind trenches.

[0069] This application also provides a packaging substrate, which is prepared by any of the processing methods described in the above embodiments. In practical applications, the packaging substrate of this application can be used in the fields of advanced packaging substrates, power electronic modules, and high-speed communication and server equipment. The advanced packaging substrate field can include chiplet heterogeneous integrated substrates, 2.5D / 3D packaging add-on boards, and high-power IC packaging substrates. The power electronic module field can include new energy vehicle power modules, industrial power modules, and embedded chip packaging (ECP) structures. The high-speed communication and server equipment field can include 5G base station motherboards, data center server motherboards, high-end router backplanes, and optical module substrates.

[0070] In the description of this application, it should be understood that terms such as “first” and “second” are used only to distinguish similar objects and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0071] The foregoing has provided a detailed description of the packaging substrate processing method and the packaging substrate provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application, and the descriptions of the embodiments above are only for the purpose of helping to understand this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for processing a packaging substrate, characterized in that, include: Process blind slots on the packaging substrate; Multiple strip-shaped dry films are formed in the blind groove at intervals, and multiple first areas to be plated are formed between the multiple strip-shaped dry films at intervals. A first electroplating process is performed to form multiple first metal filling structures in the multiple first areas to be plated. Remove the plurality of strip-shaped dry films and form a dry film on the surface of the plurality of first metal filling structures, and form a plurality of second areas to be plated spaced apart between the plurality of first metal filling structures; A second electroplating process is performed to form multiple second metal filling structures in the multiple second areas to be plated, and the multiple second metal filling structures are combined with the multiple first metal filling structures.

2. The packaging substrate processing method according to claim 1, characterized in that, The formation of multiple strip-shaped dry films spaced apart within the blind groove includes: A first dry film is attached to the surface of the packaging substrate, and the first dry film partially fills the blind groove; The first dry film is exposed using the first photomask; The first dry film after exposure is developed to remove part of the first dry film, so that multiple strip-shaped dry films are formed in the blind groove.

3. The packaging substrate processing method according to claim 1, characterized in that, The process of forming a dry film on the surfaces of the plurality of first metal-filled structures includes: A second dry film is attached to the surface of the packaging substrate, and the second dry film covers the surfaces of the plurality of first metal-filled structures. The second dry film is exposed using a second photomask; The exposed second dry film is developed to remove a portion of the second dry film, thereby forming a dry film on the surfaces of the plurality of first metal-filled structures.

4. The packaging substrate processing method according to any one of claims 1 to 3, characterized in that, Before forming a plurality of spaced strip-shaped dry films within the blind groove, the method further includes: Residual resin on the inner wall of the blind groove is removed by plasma cleaning; A copper seed layer is deposited on the inner wall of the blind tank using a chemical copper plating process.

5. The packaging substrate processing method according to any one of claims 1 to 3, characterized in that, The removal of the plurality of strip-shaped dry films includes: The multiple strip-shaped dry films were removed using NaOH stripping solution.

6. The packaging substrate processing method according to any one of claims 1 to 3, characterized in that, After the second electroplating, the process also includes: The metal filling layer in the blind slot is brushed using a mechanical brushing machine to make the surface of the metal filling layer flush with the surface of the packaging substrate. The metal filling layer is formed by combining the plurality of second metal filling structures and the plurality of first metal filling structures.

7. The packaging substrate processing method according to any one of claims 1 to 3, characterized in that, The process of fabricating blind slots on the packaging substrate includes: The packaging substrate is processed using a CO2 laser to form blind grooves on the packaging substrate. The length and width of the blind grooves are both greater than 1 mm, and the direction of the length and the direction of the width are both parallel to the surface of the packaging substrate.

8. The packaging substrate processing method according to claim 7, characterized in that, The blind groove is 2mm long, 2mm wide, and 50μm deep.

9. The packaging substrate processing method according to any one of claims 1 to 3, characterized in that, Before processing the blind trench on the packaging substrate, the method further includes: Provide core boards; A dielectric layer and copper foil are laminated onto the core board to form a packaging substrate.

10. A packaging substrate, characterized in that, The packaging substrate is prepared by the processing method according to any one of claims 1 to 9.

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