High-density interconnection board thin structure and manufacturing method

Abstract

The application relates to a high-density interconnection board thinning structure and a manufacturing method, which comprises a sub-board, an inner-layer core board and a prepreg. The sub-board comprises a first copper layer and a first dielectric layer, the first dielectric layer is split from N prepregs of an original thick dielectric HDI, and blind holes are arranged on the surface of the sub-board; the inner-layer core board comprises a second copper layer, a second dielectric layer and a third copper layer; the prepreg is arranged between the sub-board and the inner-layer core board, and the sub-board, the prepreg and the inner-layer core board are formed through vacuum hot pressing. The method realizes efficient and low-damage thinning processing of the thick dielectric HDI board under the premise of ensuring the precision and structural strength of the blind holes, and meets the requirements of pressure resistance, anti-layering performance and electroplating hole filling stability in high-standard application scenes such as vehicle-mounted devices.

Description

Technical Field

[0001] This application relates to the field of high-density interconnect board processing technology, and more specifically, to a thin structure and manufacturing method for a high-density interconnect board. Background Technology

[0002] High-density interconnect (HDI) boards are widely used in electronic devices, especially in fields with high reliability requirements such as automotive. In existing technologies, blind via fabrication of thick dielectric HDI boards typically employs methods such as lamination followed by laser drilling, etching-assisted drilling, or controlled-depth drilling combined with laser drilling. However, these methods have several problems in actual processing. For example, CO2 laser processing results in significant heat-affected zones, easily causing carbonization of the via walls and poor plating adhesion; controlled-depth drilling, due to its large processing tolerances, often results in inconsistent blind via depths, leading to interconnect failure or penetration of the inner copper foil. To solve these problems, a novel thinner structure and manufacturing method are needed that can effectively control dielectric thickness and blind via precision, reducing processing damage. Summary of the Invention

[0003] The purpose of this application is to provide a thin structure and manufacturing method for a high-density interconnect board, which can effectively control the dielectric thickness and the accuracy of blind vias.

[0004] To achieve the above objectives, a method for fabricating thin high-density interconnect boards is proposed, comprising the following steps: Provide a sub-board, and machine blind holes on the surface of the sub-board; Fill the blind holes with a cured material, making the cured material flush with the side edge of the sub-board; The processed sub-boards are stacked with prepreg and inner core board in sequence, and then pressed together to form an integrated motherboard. Remove the cured material from the integrated motherboard to expose the blind holes and the prepreg at the bottom; Laser coarse drilling is performed on the prepreg at the blind hole location to form an opening area on the prepreg; Laser finishing is performed on the edges of the blind holes.

[0005] In one embodiment, before the sub-board is processed, the double-sided core board is cut by cutting, and then the copper layer on one side of the double-sided core board is removed by etching to obtain a sub-board with a single-sided copper layer.

[0006] In one embodiment, blind hole positions are located on the surface of the sub-plate and formed by machining.

[0007] In one embodiment, the solidified material is soluble, and after filling, the edge of the solidified material is made flush with the side of the sub-board by grinding.

[0008] In one embodiment, the solidified material in the integrated motherboard is removed by dissolving it with a chemical solution.

[0009] In one embodiment, the laser rough opening path is a first path, which is annular and has a diameter smaller than that of the blind hole. The laser rough opening is performed by a first laser, which opens the hole along the first path. The processing area of ​​the first laser is located inside the blind hole.

[0010] In one embodiment, the laser finishing path is a second path, which is circular. The laser finishing is performed by a second laser, which covers the sidewall portion of the blind hole on the second path.

[0011] In one embodiment, the intensity of the first laser is higher than that of the second laser, enabling the rapid formation of an opening area on the prepreg.

[0012] A thin high-density interconnect board structure, fabricated using the aforementioned thin high-density interconnect board fabrication method, includes: A sub-board, comprising a first copper layer and a first dielectric layer, wherein blind vias are formed on the surface of the sub-board; The inner core board includes a second copper layer, a second dielectric layer, and a third copper layer; A prepreg is disposed between the sub-board and the inner core board, and the sub-board, the prepreg, and the inner core board are formed by vacuum hot pressing.

[0013] In one embodiment, the second copper layer, the second dielectric layer, and the third copper layer are stacked sequentially.

[0014] The above technical solution effectively solves the problems of hole wall carbonization, poor plating adhesion, and blind holes not penetrating or puncturing the inner copper foil caused by heat effects and processing tolerances during the blind hole processing of traditional thick dielectric HDI boards. Specifically, this method first pre-processes blind holes on a sub-board and fills them with a soluble curing agent until flush with the side edge of the sub-board. Then, it is stacked and pressed with a prepreg and an inner core board to form an integrated motherboard. Subsequently, the curing agent is removed by dissolving it with a chemical solution to expose the blind holes. Then, laser technology is used to coarsely open the inside of the blind holes to form an opening area, and the side wall edges of the blind holes are further refined by laser. This segmented processing method significantly reduces the heat effect of laser processing on the dielectric layer and copper layer, avoiding problems such as hole wall carbonization and poor plating adhesion. At the same time, the pre-filling of the curing agent achieves uniform control of the dielectric layer thickness, reducing the phenomenon of inconsistent blind hole depth caused during the pressing process, thereby improving the processing consistency and reliability of blind holes. Ultimately, this method achieves efficient and low-damage thinning of thick dielectric HDI boards while ensuring through-hole accuracy and structural strength, meeting the requirements for pressure resistance, anti-delamination performance, and electroplating filling stability in high-standard application scenarios such as automotive.

[0015] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart illustrating a method for thinning a high-density interconnect board as provided in an embodiment of this application; Figure 2 A schematic diagram of the sub-board openings provided in an embodiment of this application; Figure 3 A schematic diagram of sub-plate filling provided in an embodiment of this application; Figure 4 A stacking diagram of the sub-board, inner core board, and prepreg provided in the embodiments of this application; Figure 5 This is a schematic diagram of an integrated motherboard provided in an embodiment of this application; Figure 6 This is a path diagram for laser coarse aperture provided in an embodiment of this application; Figure 7 A path diagram for laser finishing provided in an embodiment of this application; Figure 8This is a schematic diagram of the integrated motherboard after laser drilling, provided in an embodiment of this application.

[0018] Icons: 100-Daughterboard; 101-First copper layer; 102-First dielectric layer; 103-Blind via; 104-Opening area; 200-Currently cured material; 300-Inner core board; 301-Second copper layer; 302-Second dielectric layer; 303-Third copper layer; 400-Prepreg; 500-First laser; 501-Second laser; 600-Integrated motherboard. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] In the description of this application, it should be noted that the terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0021] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] Currently, the industry commonly uses processing methods such as lamination followed by laser drilling, etching-assisted drilling, and controlled-depth drilling combined with laser drilling, all of which have significant technical limitations. Conventional CO2 laser processing involves multiple passes, resulting in significant heat-affected zones that easily cause hole wall carbonization and poor coating adhesion; traditional controlled-depth drilling methods have inherent processing tolerances, which can easily lead to uneven thickness of the underlying medium.

[0023] Alternatively, deep blind vias can be fabricated using controlled-depth drilling followed by laser drilling. However, due to the inherent tolerances of controlled-depth drilling, inconsistent thickness of the underlying dielectric layer can occur. More importantly, existing processes employ a core logic of lamination followed by drilling. The dielectric layer itself exhibits uneven thickness after lamination, which, combined with the tolerance defects of controlled-depth drilling, further exacerbates the deviation in drilling depth consistency. In mass production, this can easily lead to problems such as blind vias not being drilled through, resulting in interconnect failure, or excessive laser energy damaging the inner copper foil. Frequent occurrences of blind via failures or excessive laser energy damaging the inner copper foil during mass production make it difficult to guarantee product yield and production stability. Therefore, this application optimizes the processing flow by adopting a segmented processing method of pre-drilling, lamination, and then laser drilling. This effectively eliminates the adverse effects of dielectric thickness deviations and drilling tolerances, enabling efficient, low-damage, and high-precision processing of deep blind vias with 0.3-0.5mm thick dielectric layers. This meets the stringent requirements of automotive HDI boards for pressure resistance, anti-delamination, and electroplating filling reliability.

[0024] Specifically, this application breaks down the original laser-processed thick dielectric L1-2 layers (0.3-0.5mm) into a single-sided core board + a single thin prepreg sheet. Then, a processing structure using pre-drilled hole plugs and lamination followed by dissolution and window opening is employed. This reduces the laser processing thickness of thick dielectric blind holes from over 100 micrometers to tens of micrometers, significantly reducing the laser processing load, mitigating the impact of thickness deviations, and ensuring consistent blind hole depth. By adjusting the number of prepreg sheets, it can flexibly adapt to the processing needs of thick dielectric HDI boards with different dielectric thicknesses within the 0.3mm-0.5mm range, resulting in stable finished product yield and enabling mass production. The specific method is as follows: Reference Figure 1 This application proposes a method for thinning a high-density interconnect board, comprising the following steps: The original thick medium N semi-cured sheets are split into a single-sided core board (sub-board) + single thin semi-cured sheet structure; A sub-board 100 is provided, and blind holes 103 are machined on the surface of the sub-board 100; Fill the blind hole 103 with cured material 200, and make the cured material 200 flush with the side of the sub-plate 100; The processed sub-board 100 is stacked with the prepreg 400 and the inner core board 300 in sequence, and then pressed together to form an integrated motherboard 600. Reference Figure 2 Remove the solidified material 200 from the integrated motherboard 600 and expose the blind hole 103; Laser rough drilling is performed inside the blind hole 103 to form an opening area 104 on the prepreg 400; Laser finishing is performed on the edge of blind hole 103 to obtain a thick dielectric deep blind hole (combined hole type of 103+104) with good hole shape.

[0025] First, a daughterboard 100 is provided. The daughterboard 100 is a single-sided core board structure, which is split from N prepreg sheets of the original thick dielectric HDI. Blind vias 103 are provided on its surface. The layout and size of the blind vias 103 are pre-planned and processed according to the circuit design requirements to ensure that they can accurately form the required micro interconnect channels in subsequent processes.

[0026] Reference Figure 3 Next, a soluble curing agent 200 is filled into the blind hole 103. During the filling process, the curing agent 200 is filled into the blind hole until it is flush with the side of the sub-plate 100, and then the curing agent 200 is shaped by baking. This ensures that the curing agent 200 can be evenly distributed during the subsequent pressing process and will not deform.

[0027] Reference Figure 4 Subsequently, the sub-board 100, after being filled with the cured material 200, is stacked with the semi-cured sheet 400 and the inner core board 300 in sequence, and then formed into an integrated motherboard 600 by vacuum hot pressing. This step not only enhances the bonding strength between the layers, but also ensures the consistency of the dielectric layer thickness, providing a structural basis for the subsequent processing of blind holes 103.

[0028] Reference Figure 5 After the integrated motherboard 600 is pressed together, the solidified material 200 inside is removed by means of a chemical solution or chemical dissolution, thereby exposing the passage of the blind hole 103. This removal process is precisely controlled to ensure that no additional damage is caused to the daughterboard 100 or other structural layers, while making the inside of the blind hole relatively flat, which is convenient for subsequent laser processing.

[0029] Reference Figure 6 Next, laser rough drilling is performed on the inside of the blind via 103 to form an opening area 104 on the prepreg 400, further expanding the blind via channel and providing operating space for subsequent fine processing. This step uses appropriate laser parameters to reduce the thermal impact on the dielectric layer and the second copper layer 301 while ensuring efficiency.

[0030] Reference Figure 7 and Figure 8 Finally, the edges of the blind via 103 are laser-finished to improve the hole shape accuracy and sidewall integrity. This finishing process effectively corrects problems such as uneven edges or burrs that may occur during the rough drilling process, thereby ensuring that the blind via has good bonding force and current conduction performance during electroplating. By laser drilling, the second copper layer 301 of the inner core board 300 is exposed, thus obtaining a formed thick dielectric deep blind via.

[0031] In some embodiments, before the sub-board 100 is processed, the double-sided core board is cut by cutting, and then the copper layer on one side of the double-sided core board is removed by etching to obtain the sub-board 100 with a single-sided copper layer.

[0032] To obtain a sub-board 100 with a single-sided copper layer, a double-sided core board with copper layers on both sides is first provided before blind via 103 processing. The double-sided core board is then cut to the required dimensions to form a preliminary sub-board structure. The cutting process uses laser cutting or mechanical cutting equipment to ensure that the sub-board 100 meets design requirements and is free of burrs and edge damage. The cut double-sided core board is then etched to remove the copper layer on one side, resulting in a sub-board 100 with only a single-sided copper layer, thus providing a substrate with a single-sided copper layer structure for subsequent blind via 103 processing.

[0033] In some embodiments, blind holes 103 are positioned on the surface of the sub-plate 100 and formed by machining.

[0034] In other embodiments, to improve the accuracy and consistency of blind via 103 processing, the position of blind via 103 is first precisely located on the surface of daughterboard 100. Positioning methods can include photoplotting alignment, laser marking, or computer-aided positioning to ensure the accurate positioning of blind via 103 and compliance with circuit design requirements. Subsequently, blind via 103 is formed on daughterboard 100 through machining techniques such as drilling, milling, or stamping. Compared to laser processing, this method is more suitable for applications with high requirements for the shape and size of blind via 103, and can effectively avoid material deformation problems caused by localized overheating or thermal stress in the copper layer due to laser processing. Furthermore, machining methods are stable, versatile, and conducive to achieving consistency in blind via 103 processing during mass production.

[0035] In some embodiments, the cured material 200 is soluble, and after filling, the edge portion of the cured material 200 is made flush with the side of the sub-board 100 by grinding.

[0036] In some embodiments, the cured material 200 is selected from soluble materials to facilitate subsequent removal processes. After the blind hole 103 is processed, the soluble cured material 200 is filled into the blind hole to support the blind hole structure and prevent it from collapsing or deforming during subsequent lamination. To ensure that the edges of the cured material 200 are flush with the sides of the sub-plate 100 and to improve the interface flatness and interlayer bonding quality during lamination, the edges of the cured material 200 are trimmed using a grinding process after filling. This grinding process can use precision grinding wheels or polishing equipment to ensure that the surface of the cured material 200 is precisely aligned with the sub-plate 100, providing a stable structural foundation for subsequent stacking and lamination processes.

[0037] In some embodiments, the solidified material 200 in the integrated motherboard 600 is removed by dissolving it with a chemical solution.

[0038] In other embodiments, a chemical dissolution method is used to remove the solidified material 200 inside the integrated motherboard 600. The chemical is selected based on the chemical properties of the solidified material 200 to achieve a highly efficient and controllable dissolution effect. After lamination to form the integrated motherboard 600, the chemical is uniformly coated on the exposed areas of the solidified material 200, and the dissolution process is accelerated by appropriate heating or immersion processes. The chemical selectively removes the solidified material 200 without damaging the daughterboard 100, the prepreg 400, or the inner core board 300, thereby exposing the channels of the blind holes 103 and providing a clear processing interface for subsequent laser rough drilling and finishing. This method is more efficient than mechanical removal and reduces physical damage to the substrate.

[0039] Due to limitations in existing technology and the constraints of laser drilling equipment, it is impossible to directly form large-diameter blind holes 103. Therefore, laser design needs to be performed within the limits of the equipment to meet the product requirements of large-diameter deep blind holes 103. Based on the hole diameter design size and the thickness of the prepreg, a step-by-step design of laser coarse drilling followed by laser fine drilling is adopted. First, a certain margin is reserved along the opening for coarse drilling to remove most of the residual medium. Then, fine drilling is performed along the target hole diameter contour to finally obtain a large-diameter blind hole with precise dimensions and smooth hole walls.

[0040] Specifically, refer to Figure 6 In some embodiments, the laser coarse opening path is a first path, the first path is annular, the diameter of the first path is smaller than the diameter of the blind hole 103, and the laser coarse opening is processed by a first laser 500. The first laser 500 opens the hole along the first path, and the processing area of ​​the first laser 500 is located inside the blind hole 103.

[0041] In some embodiments, to improve the processing efficiency of the blind hole 103 and ensure the accuracy of subsequent finishing, a laser roughing process is used to initially process the blind hole. During this process, the laser roughing path is designed as a first path, and this path has a ring structure with a diameter smaller than the designed aperture of the blind hole 103. The first laser 500 processes along this first path, performing the opening operation only in the internal region of the blind hole 103, avoiding unnecessary damage to the sub-board 100 or other layer structures. In this way, the laser roughing can complete the approximate processing of the blind hole 103's outline in a short time, forming a coarse hole at the bottom of the blind hole 103 with a size slightly smaller than the designed aperture, leaving only a small amount of dielectric layer for subsequent removal. The edge of this roughing process is approximately 0.05 mm from the aperture edge of the blind hole 103, reserving adjustment space for the finishing process and laying the foundation for subsequent precise processing.

[0042] Reference Figure 7 In some embodiments, the laser finishing path is a second path, which is circular. The laser finishing is performed by a second laser 501, which covers the sidewall portion of the blind hole 103 on the second path.

[0043] In other embodiments, a laser finishing stage is used to further correct the dimensions and perpendicularity of the blind via 103 to meet the requirements of high-precision interconnection. In this stage, the laser finishing path is designed as a second path, also a ring structure, but its scanning range covers the sidewall portion of the blind via 103, ensuring the uniformity and accuracy of the via wall. The second laser 501 processes along the second path using smaller energy parameters to remove residual media from the roughing process while avoiding excessive ablation or damage to the sidewall of the blind via. This finishing method effectively removes the dielectric material near the edge of the rough via, ensuring that the final blind via 103 has a diameter that closely matches the design dimensions and meets stringent tolerance requirements. This process provides a high-quality process foundation for subsequent electroplating filling of the blind via, improving overall interconnect performance and reliability.

[0044] In some embodiments, the intensity of the first laser 500 is higher than that of the second laser 501, thereby forming an opening region 104 on the prepreg 400, thereby exposing the second copper layer 301 to the opening region 104.

[0045] In some embodiments, to process the blind via 103 and subsequently connect it to the second copper layer 301, two laser processing steps with different intensities are used to complete the roughing and finishing steps, respectively. The intensity of the first laser 500 is higher than that of the second laser 501. The first laser 500 is mainly used in the roughing stage; its high energy can quickly penetrate the prepreg 400, forming an opening 104 of a certain size in the blind via 103 region. This opening 104 effectively exposes the second copper layer 301, providing a physical channel and electrical connection basis for subsequent electroplating filling or conductive processes.

[0046] In this embodiment, a micro-blind via size of 0.15–0.175 mm is selected to meet the fine interconnect requirements of high-density interconnect boards. For this small aperture, a ring-shaped laser scanning path is used, aiming at "path scanning and ablation to form the via." The laser gradually ablates along a predetermined path to form the blind via structure, improving processing accuracy and consistency. This process ensures controllable blind via shape while effectively avoiding overburning of the dielectric layer or damage to the copper layer due to excessive laser energy, thus guaranteeing the structural integrity and conductivity of the blind via area.

[0047] Subsequently, a second laser 501 is used in the finishing stage. Its energy parameters are relatively low to prevent unnecessary damage to the exposed copper layer. The second laser 501 scans along the sidewall of the blind via 103 to further remove residual dielectric material after the initial opening, correct the hole diameter and perpendicularity to the hole wall, and ensure that the shape and size of the opening region 104 meet design requirements. This also ensures the reliable exposure of the second copper layer 301.

[0048] In this embodiment, to further improve the accuracy and controllability of blind hole machining, micro blind holes with a single diameter of 0.1–0.125 mm are used for low-energy fine finishing of the hole walls of deep blind holes. This micro blind hole design maintains an overlap range of less than 1 / 2 between holes to reduce interference and overlap during machining, thereby improving machining efficiency and hole shape consistency. This design aims at "hole shape finishing" and achieves the machining of blind hole structures by precisely controlling the laser scanning path and energy parameters.

[0049] The embodiments of this application also propose a thin high-density interconnect board structure, manufactured using the above-described thin high-density interconnect board fabrication method, comprising a sub-board 100, an inner core board 300, and a prepreg 400. The sub-board 100 includes a first copper layer 101 and a first dielectric layer 102, and blind vias 103 are formed on the surface of the sub-board 100; the inner core board 300 includes a second copper layer 301, a second dielectric layer 302, and a third copper layer 303; the prepreg 400 is disposed between the sub-board 100 and the inner core board 300, and the sub-board 100, the prepreg 400, and the inner core board 300 are formed by vacuum hot pressing.

[0050] A prepreg 400 is disposed between the daughterboard 100 and the inner core board 300 to bond the daughterboard 100 and the inner core board 300 together during the lamination process, forming a stable structure. The daughterboard 100, the prepreg 400, and the inner core board 300 are combined by vacuum thermoforming to form an integrated thin interconnect structure. This structure achieves high-density interconnection and thinness through precise blind via 103 machining and multi-layer copper stacking design, making it suitable for high-density, high-performance electronic packaging applications.

[0051] In some embodiments, the second copper layer 301, the second dielectric layer 302, and the third copper layer 303 are stacked sequentially.

[0052] The second copper layer 301, the second dielectric layer 302, and the third copper layer 303 are stacked sequentially. Specifically, the second copper layer 301, as one of the conductive layers of the inner core board 300, is located at the bottom; the second dielectric layer 302 is next, used to achieve interlayer insulation and dielectric support; and the third copper layer 303 serves as the upper conductive layer, working in conjunction with the second copper layer 301 to form an internal interconnect structure. This layered stacking design not only improves the electrical conductivity of the inner core board 300 but also enhances the overall mechanical strength and stability of the board.

[0053] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0054] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for thinning a high-density interconnect board, characterized in that, Includes the following steps: A sub-board (100) is provided, and blind holes (103) are machined on the surface of the sub-board (100). Fill the blind hole (103) with cured material (200) and make the cured material (200) flush with the side of the sub-plate (100); The processed sub-board (100) is stacked with a prepreg (400) and an inner core board (300) in sequence, and then pressed together to form an integrated motherboard (600). Remove the cured material (200) from the integrated motherboard (600) to expose the blind hole (103) and the prepreg (400) at the bottom. Laser rough drilling is performed on the prepreg (400) at the blind hole (103) position to form an opening area (104) on the prepreg (400). Laser finishing is performed on the edge portion of the blind hole (103).

2. The method for thinning a high-density interconnect board according to claim 1, characterized in that, Before processing the sub-board (100), the double-sided core board is cut by cutting, and then the copper layer on one side of the double-sided core board is removed by etching to obtain the sub-board (100) with a single-sided copper layer.

3. The method for thinning a high-density interconnect board according to claim 1, characterized in that, The blind hole (103) is located on the surface of the sub-plate (100) and formed by machining.

4. The method for thinning a high-density interconnect board according to claim 1, characterized in that, The solidified material (200) is soluble. After filling, the edge of the solidified material (200) is made flush with the side of the sub-board (100) by grinding.

5. The method for thinning a high-density interconnect board according to claim 1, characterized in that, The solidified material (200) in the integrated motherboard (600) is removed by dissolving it with a chemical solution.

6. The method for thinning a high-density interconnect board according to claim 1, characterized in that, The laser rough opening path is the first path, which is annular. The diameter of the first path is smaller than the diameter of the blind hole (103). The laser rough opening is processed by the first laser (500). The first laser (500) opens the hole along the first path. The processing area of ​​the first laser (500) is located inside the blind hole (103).

7. The method for thinning a high-density interconnect board according to claim 6, characterized in that, The laser finishing path is the second path, which is a ring. The laser finishing is performed by the second laser (501), which covers the side wall portion of the blind hole (103) on the second path.

8. The method for thinning a high-density interconnect board according to claim 7, characterized in that, The intensity of the first laser (500) is higher than that of the second laser (501), thereby enabling the rapid formation of an opening area (104) on the prepreg (400).

9. A thin structure for a high-density interconnect board, characterized in that, The high-density interconnect board is manufactured using the high-density interconnect board thinning method as described in any one of claims 1-8, comprising: The sub-board (100) includes a first copper layer (101) and a first dielectric layer (102), and a blind hole (103) is formed on the surface of the sub-board (100). The inner core board (300) includes a second copper layer (301), a second dielectric layer (302) and a third copper layer (303). A prepreg (400) is disposed between the sub-plate (100) and the inner core plate (300), and the sub-plate (100), the prepreg (400) and the inner core plate (300) are formed by vacuum hot pressing.

10. The high-density interconnect board thinning structure according to claim 9, characterized in that, The second copper layer (301), the second dielectric layer (302), and the third copper layer (303) are stacked sequentially.

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