Preparation method of packaging substrate and packaging substrate

Abstract

The invention discloses a preparation method of a packaging substrate and the packaging substrate. The method comprises the following steps: acquiring a to-be-processed packaging substrate; the to-be-processed packaging substrate comprises at least one groove and at least one hole; performing partial metal filling on each groove to form a pre-filled packaging substrate; and full-board hole-filling electroplating is carried out on the pre-filled packaging substrate, and the grooves and the holes are filled and leveled up to obtain a target packaging substrate meeting the sinking condition. Through the method of pre-filling the groove in the packaging substrate and then completely filling the hole and the groove, the packaging substrate meeting the sinking requirement is obtained, and the filling difficulty of the groove and the hole can be reduced under the condition that the groove and the hole exist in the packaging substrate at the same time.

Description

Technical Field

[0001] The present application relates to the technical field of packaging substrates, and in particular to a method for preparing a packaging substrate and a packaging substrate. Background Art

[0002] With the development of high voltage and high current packaging substrates, the requirements for heat dissipation and thermal conductivity of packaging substrates are getting higher and higher. The heat dissipation performance of packaging substrates directly affects the stability and life of electronic devices. For this reason, packaging substrates for power management integrated circuits (PowerManagement IC, PMIC) came into being.

[0003] However, in the actual production process, large-area rows of holes are connected into slots on the package substrate. However, due to the large difference in the ratio of the slot area to the hole, it is more difficult to fill the slot than to fill the hole. If the slot is difficult to be effectively filled, it will affect the performance and reliability of the electronic device. At the same time, since there are some small-area holes on the package substrate, these holes are difficult to be optimized into slots, resulting in the existence of both slots and holes on the package substrate. This coexistence of slots and initial holes further increases the difficulty of filling the slots and filling the initial holes. Summary of the invention

[0004] The main technical problem solved by the present application is to provide a method for preparing a packaging substrate and a packaging substrate, which can solve the technical problem of reducing the difficulty of filling the grooves and holes when there are grooves and holes in the packaging substrate at the same time.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: the preparation method comprises:

[0006] Obtaining a package substrate to be processed; the package substrate to be processed comprises at least one groove and at least one hole;

[0007] Partially filling each of the grooves with metal to form a pre-filled packaging substrate;

[0008] The pre-filled packaging substrate is subjected to full-board hole-filling electroplating to fill each of the grooves and each of the holes, thereby obtaining a target packaging substrate that meets a preset recess condition.

[0009] Optionally, after the step of partially filling each groove with metal to form a pre-filled package substrate, before the step of performing full-board hole-filling electroplating on the pre-filled package substrate to fill each groove and each hole to obtain a target package substrate that meets a preset recess condition, the method further includes:

[0010] The metal filler protrusions on the top or side of each groove after partial metal filling are brushed flat.

[0011] Optionally, the step of partially filling each of the grooves with metal to form a pre-filled packaging substrate includes:

[0012] Obtaining the depth of each of the grooves and the proportional depth of partial filling, and determining the metal filling amount required for partial filling of each of the grooves;

[0013] Filling each of the grooves with a metal filler corresponding to the metal filling amount to form the pre-filled packaging substrate.

[0014] Optionally, the proportion of the partial filling is 20% to 60% of the depth of each of the grooves before filling.

[0015] Optionally, the step of filling the metal filler corresponding to the metal filling amount into each of the grooves to form the pre-filled packaging substrate includes:

[0016] Performing photolithography on the package substrate to be processed to expose the grooves;

[0017] The metal filler corresponding to the metal filling amount is electroplated into each of the grooves by using a pattern electroplating method to form the pre-filled packaging substrate.

[0018] Optionally, the step of performing photolithography on the to-be-processed packaging substrate to expose each of the grooves comprises:

[0019] The package substrate to be processed is subjected to pattern and electrical lamination, and the regions corresponding to the grooves are subjected to exposure and development treatment to expose the grooves.

[0020] Optionally, the step of performing full-board hole-filling electroplating on the pre-filled packaging substrate to fill each of the grooves and each of the holes to obtain a target packaging substrate that meets a preset recess condition includes:

[0021] Determining electroplating parameters corresponding to the depression depths of the grooves and holes according to the metal filling amount;

[0022] Based on the electroplating parameters, the pre-filled packaging substrate is subjected to full-board hole-filling electroplating to fill each of the grooves and each of the holes, thereby obtaining a target packaging substrate that meets a preset recess condition.

[0023] Optionally, the step of obtaining a package substrate to be processed includes:

[0024] Obtaining an initial packaging substrate, and forming the grooves and the holes on the initial packaging substrate by using a laser drill;

[0025] The initial packaging substrate is subjected to copper flash plating to obtain the packaging substrate to be processed.

[0026] Optionally, the depression condition is that the depression depths of the groove and the hole are both less than or equal to 3 μm.

[0027] In order to solve the above technical problems, another technical solution adopted in the present application is: a packaging substrate, the packaging substrate comprises filled grooves and holes, and the packaging substrate is prepared by any of the above-mentioned packaging substrate preparation methods.

[0028] Different from the prior art, the present application provides a method for preparing a packaging substrate, the method comprising: obtaining a packaging substrate to be processed; the packaging substrate to be processed comprises at least one groove and at least one hole; partially filling each groove with metal to form a pre-filled packaging substrate; performing full-plate hole-filling electroplating on the pre-filled packaging substrate to fill each groove and each hole to obtain a target packaging substrate that meets the preset recess condition. By pre-filling the grooves on the packaging substrate first, and then completely filling the holes and the grooves to form the target packaging substrate, the difficulty of filling the grooves and holes can be reduced when the packaging substrate has both grooves and holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic flow chart of a first embodiment of a method for preparing a packaging substrate of the present application;

[0030] Figure 2 It is a schematic flow chart of a second embodiment of a method for preparing a packaging substrate of the present application;

[0031] Figure 3 is a schematic flow chart of a third embodiment of a method for preparing a packaging substrate of the present application;

[0032] Figure 4a It is a schematic diagram of the laser groove burning process of the method for preparing the packaging substrate of the present application;

[0033] Figure 4b It is a schematic diagram of the de-drilling, copper deposition and flash plating processes of the preparation method of the packaging substrate of the present application;

[0034] Figure 4c It is a schematic diagram of the preparation method of the packaging substrate of the present application and the electrical film bonding process;

[0035] Figure 4d It is a schematic diagram of the electrical exposure and development process of the method for preparing the packaging substrate of the present application;

[0036] Figure 4e It is a schematic diagram of a pattern electroplating process of a method for preparing a packaging substrate of the present application;

[0037] Figure 4f It is a schematic diagram of a metal filler protrusion in the method for preparing a packaging substrate of the present application;

[0038] Figure 4g It is a schematic diagram of the preparation method of the packaging substrate of the present application after the brushing process;

[0039] Figure 4h It is a schematic diagram of the full-board hole-filling electroplating process of the packaging substrate preparation method of the present application.

[0040] Reference numerals: package substrate to be processed 1; groove 2; hole 3; copper layer 4; dry film 5; pre-filled package substrate 6; metal filler protrusion 7; target package substrate 8. DETAILED DESCRIPTION

[0041] The present application is described in detail below with reference to the accompanying drawings and implementation methods.

[0042] This embodiment takes into account that with the development of high-voltage and high-current packaging substrates, the requirements for heat dissipation and thermal conductivity of packaging substrates are getting higher and higher. Power management integrated circuit packaging substrates are then introduced into production. However, in the actual production process, large-area rows of holes are connected into slots, and filling slots is more difficult than filling holes. If the slots cannot be filled, the heat dissipation and thermal conductivity requirements cannot be met. Moreover, some small-area holes cannot be optimized into slots, resulting in the coexistence of slots and holes on the packaging substrate, further increasing the difficulty of filling slots and holes.

[0043] In order to solve the technical problem of reducing the difficulty of filling the grooves and holes when there are both grooves and holes on the packaging substrate, this embodiment uses a method of pre-filling the grooves, and then completely filling the holes and the grooves, so that the grooves and holes on the packaging substrate can meet the concave requirements. The packaging substrate prepared by this embodiment can be applied to microphones, microphones, mics, and other non-metallized sound holes. Please refer to Figure 1 , Figure 1 1 is a flow chart of the first embodiment of the method for preparing a package substrate of the present application. It should be noted that if there is substantially the same result, the method of the present application is not limited to Figure 1 The process sequence shown is limited. Figure 1 As shown, the preparation method comprises:

[0044] Step S110, obtaining a package substrate to be processed; the package substrate to be processed comprises at least one groove and at least one hole;

[0045] Among them, the packaging substrate can provide electrical connection, protection, support, heat dissipation, assembly and other functions for the chip, and can be a carrier for semiconductor chip packaging. The packaging substrate to be processed has been pre-opened with grooves and holes. The groove can be a slot hole, and the slot hole can be a special hole design of the power management integrated circuit packaging substrate, that is, it can be a dense hole or a row of holes opened and connected into a groove, called a slot hole, and its heat dissipation area is larger than that of the hole. The hole can be a blind hole or a through hole; a blind hole can be a conductive hole on the packaging substrate that connects between layers but does not penetrate the entire board, and can be drilled by a single-sided laser drill; a through hole can be a conductive hole on the packaging substrate that connects between layers and penetrates the entire board, and can be drilled by a double-sided laser drill.

[0046] Step S120, partially filling each of the grooves with metal to form a pre-filled packaging substrate;

[0047] Specifically, pre-filling the package substrate means that all the grooves on the package substrate are partially filled with metal. Since the grooves are large and difficult to fill, by pre-filling the package substrate with metal, the recessed depth of the grooves and the recessed depth of the holes can be balanced during the subsequent full-board hole-filling electroplating, thereby improving the uniformity and quality of metal filling.

[0048] In an exemplary embodiment, the packaging substrate can be de-drilled, copper-plated and flash-plated; then, the packaging substrate is subjected to pattern electroplating, and the positions of the grooves are exposed and developed to expose the grooves; then, the exposed grooves are partially filled with metal using pattern electroplating to form a pre-filled packaging substrate.

[0049] Step S130, performing full-board hole-filling electroplating on the pre-filled packaging substrate to fill each of the grooves and each of the holes to obtain a target packaging substrate that meets a preset recess condition.

[0050] Specifically, in order to improve the filling effect of the holes and grooves of the packaging substrate, the packaging substrate after partial metal filling can be subjected to full-board hole-filling electroplating. The full-board hole-filling electroplating can be performed by uniformly depositing metal into all holes and all incompletely filled grooves through electrochemical reaction, thereby making the grooves and holes of the packaging substrate meet the recessed conditions.

[0051] In an exemplary embodiment, the sag condition may be less than or equal to the requirement of the sag standard.

[0052] In yet another exemplary embodiment, the recess condition may be less than or equal to 3 μm.

[0053] In this embodiment, a target packaging substrate is formed by pre-filling the grooves on the packaging substrate and then completely filling the holes and the grooves. This can reduce the difficulty of filling the grooves and the holes when both grooves and holes exist on the packaging substrate.

[0054] Furthermore, in the existing full-plate hole-filling electroplating, it is difficult to completely fill the package substrate with both slots and holes by electroplating alone, resulting in a recessed depth in the filled slots and / or holes. The recessed depth refers to the vertical height of the unfilled position from the plane of the package substrate.

[0055] Therefore, in this embodiment, while partially filling the groove with metal, the electroplating parameters corresponding to the recessed depth of the groove and the hole are determined according to the metal filling amount required for the partial filling of the groove, and the full-board hole filling electroplating is performed on the pre-filled packaging substrate according to the electroplating parameters, so that the filling accuracy of the groove and the hole can be improved when the full-board hole filling electroplating of the packaging substrate is performed. Figure 2 , Figure 2 1 is a flow chart of a second embodiment of a method for preparing a package substrate of the present application. In this embodiment, the method comprises the following steps:

[0056] Step S210, obtaining a package substrate to be processed; the package substrate to be processed comprises at least one groove and at least one hole;

[0057] The above step S110 may be performed and will not be described in detail here.

[0058] Step S220, obtaining the depth of each of the grooves and the proportional depth of partial filling, and determining the metal filling amount required for partial filling of each of the grooves;

[0059] Specifically, in order to accurately control the amount of metal deposited during partial metal electroplating and avoid over- or under-filling of slots and holes, the proportional depth of all slots that need to be partially filled can be predetermined to obtain the metal filling amount.

[0060] In an exemplary embodiment, the depth of the groove and the proportional depth of the partial fill can be converted into a desired metal fill amount based on the shape of the groove, metal density and electroplating efficiency.

[0061] In yet another exemplary embodiment, the hole depth, the groove depth, and the partial fill ratio depth may be combined to convert to a desired metal fill amount based on the groove shape, metal density, and electroplating efficiency.

[0062] Furthermore, the proportion of the partial filling is 20% to 60% of the depth of each of the grooves before filling.

[0063] Specifically, in order to ensure the uniformity of current distribution during the electroplating process, so that metal ions are evenly deposited and uneven coatings are avoided, the slots can be pre-filled within a ratio of 20% to 60%, thereby stabilizing the subsequent full-board hole-filling electroplating process and reducing fluctuations in electroplating parameters.

[0064] Step S230 , filling the metal filler corresponding to the metal filling amount into each of the grooves to form the pre-filled packaging substrate.

[0065] Specifically, the metal filler can be a metal material deposited in the groove by an electroplating process. For example, in a pattern electroplating process, metal ions can be deposited in the groove under the action of an electric field so that the metal filler in the groove meets the metal filling amount.

[0066] Step S240, determining the electroplating parameters of the full-plate hole-filling electroplating according to the metal filling amount; specifically, the electroplating parameters may include at least one of current density, voltage, electroplating time, electrolyte composition, and electrolyte temperature. Among them, the current density can be used to affect the reduction rate of metal ions and the thickness of the coating. The voltage can be applied to both ends of the electrolytic cell during the electroplating process, affecting the distribution of current and the electroplating efficiency. The electroplating time can determine the final thickness of the coating. The electrolyte composition can affect the properties and quality of the coating. The electrolyte temperature can affect the movement speed of metal ions and the electroplating reaction rate.

[0067] Step S250, based on the electroplating parameters, performing full-board hole-filling electroplating on the pre-filled packaging substrate to fill each of the grooves and each of the holes to obtain a target packaging substrate that meets a preset recess condition.

[0068] In an exemplary embodiment, the current density, voltage and plating time of the full-board hole-filling electroplating can be adjusted according to the pre-filling ratio to ensure that the metal can be evenly deposited. At the same time, the metal ion concentration and additive ratio in the electrolyte are adjusted, and the temperature of the electrolyte is controlled to optimize the movement speed and deposition rate of the metal ions to form a target packaging substrate, in which the groove and hole depression depths of the target packaging substrate are less than or equal to 3μm.

[0069] In another exemplary embodiment, a pulse current is used for full-board hole-filling electroplating. By intermittently applying current, metal ions are allowed to be more evenly distributed and deposited in the grooves and holes. At the same time, multiple electroplating methods can also be used, with intermediate cleaning and testing after each electroplating, and filling layer by layer to form a target packaging substrate.

[0070] In this embodiment, according to the depth and proportional depth of the groove, most of the gaps in the groove are pre-filled, so that in the subsequent full-board hole-filling electroplating process, the metal filler can be controlled according to the electroplating parameters to uniformly fill the entire groove and hole, thereby improving the filling accuracy of the groove and hole.

[0071] See also Figure 3 , Figure 3 1 is a flow chart of a third embodiment of a method for preparing a package substrate of the present application. In this embodiment, the method comprises the following steps:

[0072] Step S310, obtaining an initial packaging substrate, and forming the grooves and the holes on the initial packaging substrate by using a laser drill;

[0073] Specifically, laser drilling technology can be used to drill high-precision grooves and holes on the package substrate, and the formed holes and grooves have a conductive dielectric thickness of 100μm. Please refer to 4a, Figure 4a It is a schematic diagram of the laser groove burning process of the method for preparing the packaging substrate of the present application, and the laser drilling technology is used to burn out the groove 2 and the hole 3 respectively on the packaging substrate 1 to be processed.

[0074] Step S320, performing copper flash plating on the initial packaging substrate to obtain the packaging substrate to be processed.

[0075] Specifically, since some tiny residues will be produced after laser drilling, these residues will affect the quality of subsequent processes. In order to ensure that the inside of the holes and slots are clean and free of residues, a de-drilling process can be used to remove these residues by chemical or mechanical means to ensure that the inside of the slots and holes are clean. At the same time, in order to provide good electrical conductivity, the residues after drilling can be cleaned and a thin layer of copper can be deposited in the slots and holes to ensure conductivity. After copper deposition, flash plating is performed in the slots and holes to further deposit a thin layer of copper to enhance electrical conductivity and facilitate subsequent pattern electroplating. You can refer to Figure 4b , Figure 4b It is a schematic diagram of the desmearing, copper deposition and flash plating processes of the preparation method of the package substrate of the present application, and a copper layer 4 with a thickness of 5 microns is formed by conducting chemical copper and flash copper on the inner walls of the groove 2 and the hole 3.

[0076] Step S330, obtaining the depth of each of the grooves and the proportional depth of partial filling, and determining the metal filling amount required for partial filling of each of the grooves;

[0077] The above step S220 may be performed and will not be described in detail here.

[0078] Step S340, performing photolithography on the package substrate to be processed to expose the grooves;

[0079] Specifically, the area to be plated is precisely defined to ensure that metal is deposited only where it is needed during the subsequent electroplating process. For example, photolithography can include patterning, film lamination, exposure, and development processes.

[0080] Furthermore, step S340 includes: performing pattern bonding film on the package substrate to be processed, and performing exposure and development processing corresponding to the area of ​​each groove to expose each groove.

[0081] Specifically, a film is attached to the surface of the package substrate, and the groove area to be filled is exposed through exposure and development steps. A photosensitive film is attached to the surface of the package substrate, which can be developed after exposure to form the desired pattern. The exposure process uses a photomask to selectively expose the photosensitive film. This step ensures that only the groove area that needs to be filled is exposed. Development: Remove the unexposed photosensitive film to expose the groove that needs to be filled. This step transfers the predetermined pattern to the package substrate, exposing the groove area that needs to be electroplated. See Figure 4c and 4d , Figure 4c It is a schematic diagram of the electrical film pasting process of the method for preparing the packaging substrate of the present application, wherein the surface of the packaging substrate 1 to be processed is covered with a dry film 5 . Figure 4d It is a schematic diagram of the photolithography exposure and development process of the preparation method of the packaging substrate of the present application, and then the groove 2 is exposed through the photolithography exposure and development process, and the position of the hole 3 is protected from light.

[0082] Step S350 , electroplating a metal filler corresponding to the metal filling amount into each of the grooves by pattern electroplating to form the pre-filled packaging substrate.

[0083] Specifically, by controlling the current of the pattern electroplating, partial electroplating can be performed in the exposed slot area. Partial filling can ensure the initial filling of the slot and improve the efficiency and uniformity of subsequent full-board hole filling electroplating. Figure 4e , Figure 4e It is a schematic diagram of the graphic electroplating process of the preparation method of the packaging substrate of the present application. A certain amount of copper is filled in the groove 2. The formed hole and groove have a conductive dielectric thickness of 100μm. According to the partial filling ratio depth of 20% to 60%, the groove is pre-filled so that the filling of the groove 2 reaches a recessed depth of 40μm to 80μm, and the hole 3 is not filled to form a pre-filled packaging substrate 6.

[0084] Furthermore, during the pattern exposure process, there may be a slight alignment error between the dry film and the groove of the package substrate, resulting in part of the groove edge not being fully exposed. This offset will affect the removal effect of the dry film, and then affect the transfer effect of the pattern. Therefore, in actual operation, the exposure area may have a slight deviation from the design pattern, resulting in the formation of small metal filler protrusions at the edge of the groove. Therefore, this embodiment removes these metal filler protrusions through the brushing process to improve the filling effect of the groove and hole and the flatness of the substrate.

[0085] Step S360, brushing flat the metal filler protrusions on the top or side of each groove after partial metal filling.

[0086] Herein, step S360 may also be executed after step S120 and before step S130.

[0087] Specifically, due to the accuracy of exposure and electroplating, metal filler protrusions may form on the groove edge. Therefore, a brushing process is added after the pattern electroplating. These metal filler protrusions can be brushed flat by mechanical brushing to ensure smooth groove edges. Figure 4f and 4g , Figure 4f It is a schematic diagram of the metal filler protrusion in the method for preparing the packaging substrate of the present application, Figure 4f Metal filler bumps 7 are shown. Figure 4g It is a schematic diagram of the preparation method of the packaging substrate of the present application after the brushing process.

[0088] Step S370, performing full-board hole-filling electroplating on the pre-filled packaging substrate to fill each of the grooves and each of the holes to obtain a target packaging substrate that meets a preset recess condition.

[0089] For details, please refer to Figure 4h , Figure 4h Schematic diagram of the full-plate hole-filling electroplating process of the preparation method of the package substrate of the present application, the full-plate hole-filling electroplating is performed to completely fill the groove 2 and the hole 3 to form a Figure 4h A target package substrate 8 is shown.

[0090] In this embodiment, a plate brushing process is added after the slot is pre-filled to make the small protrusions on the slot edge flat. The slot is pre-filled first to fill a certain amount of copper in the slot, and a plate brushing process is added after the slot is pre-filled to make the small metal protrusions on the slot edge flat. The last step is to fill the holes of the whole board with electroplating, and simultaneously fill the remaining holes and the slots that are not completely filled, so that the overall level of the slots and holes is equivalent, avoiding the holes being filled while the slots are not filled, and improving the filling effect of the slots and holes.

[0091] In addition, this embodiment further provides a packaging substrate, which includes filled grooves and holes, and the packaging substrate is prepared by any of the above-mentioned methods for preparing a packaging substrate.

[0092] In the several embodiments provided in the present application, it should be understood that the disclosed methods, packaging substrates, electronic devices and storage media can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0093] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0094] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0095] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (processor) to perform all or part of the steps of the preparation method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0096] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a packaging substrate, characterized in that: The preparation method comprises: Obtaining a package substrate to be processed; the package substrate to be processed comprises at least one groove and at least one hole; Partially filling each of the grooves with metal to form a pre-filled packaging substrate; The pre-filled packaging substrate is subjected to full-board hole-filling electroplating to fill each of the grooves and each of the holes, thereby obtaining a target packaging substrate that meets a preset recess condition.

2. The preparation method according to claim 1, characterized in that: After the step of partially filling each of the grooves with metal to form a pre-filled package substrate, before the step of performing full-board hole-filling electroplating on the pre-filled package substrate to fill each of the grooves and each of the holes to obtain a target package substrate that meets the preset recess condition, the method further includes: Brush flat the metal filler protrusion on the top or side of at least one groove after partial metal filling.

3. The preparation method according to claim 1 or 2, characterized in that: The step of partially filling each of the grooves with metal to form a pre-filled packaging substrate comprises: Obtaining the depth of each of the grooves and the proportional depth of partial filling, and determining the metal filling amount required for partial filling of each of the grooves; Filling each of the grooves with a metal filler corresponding to the metal filling amount to form the pre-filled packaging substrate.

4. The preparation method according to claim 3, characterized in that: The ratio of the partial filling is 20% to 60% of the depth of each of the grooves before filling.

5. The preparation method according to claim 3, characterized in that: The step of filling the metal filler corresponding to the metal filling amount into each of the grooves to form the pre-filled packaging substrate comprises: Performing photolithography on the package substrate to be processed to expose the grooves; The metal filler corresponding to the metal filling amount is electroplated into each of the grooves by using a pattern electroplating method to form the pre-filled packaging substrate.

6. The preparation method according to claim 5, characterized in that: The step of photolithography the to-be-processed packaging substrate to expose each of the grooves comprises: The package substrate to be processed is subjected to pattern and electrical lamination, and the regions corresponding to the grooves are subjected to exposure and development treatment to expose the grooves.

7. The preparation method according to claim 3, characterized in that: The step of performing full-board hole-filling electroplating on the pre-filled package substrate to fill each of the grooves and each of the holes to obtain a target package substrate that meets the preset recess condition comprises: Determining electroplating parameters corresponding to the recess depths of the grooves and holes according to the metal filling amount; Based on the electroplating parameters, the pre-filled packaging substrate is subjected to full-board hole-filling electroplating to fill each of the grooves and each of the holes, thereby obtaining a target packaging substrate that meets a preset recess condition.

8. The method according to claim 1, characterized in that The step of obtaining a package substrate to be processed comprises: Obtaining an initial packaging substrate, and forming the grooves and the holes on the initial packaging substrate by using a laser drill; The initial packaging substrate is subjected to copper flash plating to obtain the packaging substrate to be processed.

9. The method according to claim 1, characterized in that: The depression condition is that the depression depths of the groove and the hole are both less than or equal to 3 μm.

10. A packaging substrate, characterized in that: The packaging substrate comprises filled grooves and holes, wherein the grooves and holes satisfy preset recess conditions, and the packaging substrate is prepared by the packaging substrate preparation method according to any one of claims 1 to 9.

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