A stepped via target structure for an IC carrier board, a processing method, a terminal and a medium

Abstract

The application belongs to the technical field of IC carrier plates, and specifically discloses a stepped via hole target structure for an IC carrier plate, a processing method, a terminal and a medium. The stepped via hole target structure comprises a via hole arranged in a carrier plate base body and first and second blind holes arranged on two side surfaces of the carrier plate. The via hole penetrates through upper and lower surfaces of the carrier plate, the first and second blind holes are arranged on the upper and lower surfaces of the carrier plate respectively, and are coaxially arranged with the via hole. The aperture of the via hole is smaller than the apertures of the first and second blind holes, and the first and second blind holes are coaxially arranged with the via hole. The first and second blind holes are used for optical alignment and identification of an exposure machine, and the via hole is used for interlayer geometric reference penetration. The stepped design that the aperture of the via hole is smaller than the apertures of the blind holes effectively blocks upper and lower processing energy interference, prevents heat damage to one side of the laser processing from the other side, and thus maintains the integrity and clarity of the edges of the double-sided target.

Description

Technical Field

[0001] This invention belongs to the field of IC substrate technology, specifically relating to a stepped through-hole target structure, processing method, terminal and medium for IC substrates. Background Technology

[0002] Currently, IC substrates are a key carrier for high-density interconnect packaging, and the industry is moving towards multi-layering, thinning, and high-precision alignment. The IC substrate manufacturing process requires multiple layer stacking operations such as exposure, etching, drilling, and lamination. The geometric superposition accuracy of the circuit patterns of each layer directly determines the product yield and conductivity reliability.

[0003] Exposure machines and laser drilling equipment generally use optical alignment targets as a reference to ensure accurate matching of multi-layer patterns. However, as line spacing decreases to the micrometer level and the diversity of board thickness and number of layers increases, traditional single through-hole or blind hole targets are gradually failing to meet the mass production requirements of IC substrates in terms of recognition accuracy and interlayer penetration.

[0004] In existing technologies, through-hole targets are commonly used to form geometric benchmarks by directly penetrating the upper and lower layers with lasers, thus achieving interlayer penetration.

[0005] In current processes, laser drilling machines often process the target on side A first, and then process side B to form a through hole. The high-energy laser on the side processed later can easily ablate the edge area of ​​the side processed first, making the edge of the target on side A blurry and affecting exposure alignment and recognition. Summary of the Invention

[0006] This invention addresses the problems in the prior art by providing a stepped through-hole target structure, processing method, terminal, and medium for IC substrates. This solves the problem in the background art where laser drilling machines often process the target on side A first, and then process side B to form a through hole. The high-energy laser on the later-processed side easily ablates the edge area of ​​the first-processed side, making the edge of the target on side A blurry and affecting exposure alignment recognition.

[0007] The technical solution adopted in this invention is as follows: In a first aspect, this application provides a stepped through-hole target structure for IC carrier boards, including through holes disposed in the carrier substrate and a first blind hole and a second blind hole located on both sides of the carrier board. The through hole penetrates the upper and lower surfaces of the carrier plate. The first blind hole and the second blind hole are located on the upper and lower surfaces of the carrier plate, respectively, and are both coaxial with the through hole. The diameter of the through hole is smaller than the diameters of the first blind hole and the second blind hole, and the first blind hole and the second blind hole are coaxially arranged. The first and second blind holes are used for optical alignment identification of the exposure machine, while the through holes are used for interlayer geometric reference penetration.

[0008] Furthermore, the diameter of the through hole is 0.8–1.2 mm, and the diameters of the first blind hole and the second blind hole are 1.4–1.8 mm.

[0009] Furthermore, an energy attenuation transition zone is provided at the connection between the wall of the through hole and the blind hole, and the energy attenuation transition zone has a smooth arc-shaped profile.

[0010] Furthermore, the bottom surfaces of the first and second blind holes are provided with a reflective layer and / or a copper plating layer.

[0011] Furthermore, the edges of the first and second blind holes are provided with an anti-corrosion protective layer or an anti-oxidation coating.

[0012] Secondly, this application provides a method for fabricating a through-hole target structure, used to prepare the through-hole target structure as described in the first aspect, the method comprising the following steps: Step S1: Determine the center point of the target on the IC carrier and establish a coaxial coordinate system. Step S2: Use the first laser energy to process a through hole through the carrier plate along the center point to form a geometric reference hole through the upper and lower surfaces of the carrier plate; Step S3: Use the second laser energy to process the first blind hole on the upper surface of the carrier plate, and use the third laser energy to process the second blind hole on the lower surface of the carrier plate. Step S4: Perform surface metallization treatment on the bottom surfaces of the first blind hole and the second blind hole respectively; The surface metallization process employs a reflective layer formation process and / or a copper plating process.

[0013] Furthermore, in the blind hole processing in step S3, a spiral scanning path from the outside to the inside is adopted, and an energy attenuation transition zone is prepared at the connection between the through hole wall and the blind hole by setting a composite distribution of laser energy reduction and local gain control. Energy control follows the following relationship:

[0014] Where r represents the radial position currently scanned by the laser beam; Indicates the radius of the blind hole; Indicates the radius of the through hole; This indicates the starting radius for energy control near the through-hole. This is a safety clearance at the edge of the through hole; Indicates the normalized radius; This represents the cumulative surface energy per unit area at radius r; This represents the baseline energy distribution that decreases from the outside in. The accumulated surface energy at the outer edge of the blind hole. This is the energy decay ratio coefficient. The energy decay index is denoted by A; A represents the local energy gain amplitude near the edge of the via, used to compensate for edge transition. The Gaussian half-width represents the local energy gain.

[0015] Furthermore, in step S4, the surface metallization treatment employs a reflective layer formation process, specifically including the following steps: Step S4-1: Perform surface pretreatment on the bottom surfaces of the first blind hole and the second blind hole. The surface pretreatment includes removing oxides, removing impurity particles, and performing surface activation treatment on the bottom surfaces of the holes. Step S4-2: Deposit a thin film of reflective material on the pretreated bottom surface of the hole. The reflective material is selected from aluminum, silver, chromium, nickel and their binary or multi-element alloys, and is formed by physical vapor deposition or chemical vapor deposition process. Step S4-3: After deposition, perform annealing in a vacuum or inert atmosphere. The inert atmosphere is nitrogen or argon, the oxygen volume fraction is not greater than 50 ppm, the annealing temperature is controlled between 150°C and 250°C, and the time is between 15 minutes and 30 minutes.

[0016] Thirdly, this application provides a terminal, including: The memory is used to store the machining program for the through-hole target structure; A processor for executing the steps of the processing method for the through-hole target structure as described in the second aspect when performing the stepped through-hole target structure for the IC substrate.

[0017] Fourthly, this application provides a computer-readable storage medium that stores computer instructions. When a computer reads the computer instructions in the storage medium, the computer executes the processing method for the through-hole target structure as described in the second aspect.

[0018] As can be seen from the above technical solutions, the advantages of the present invention are: In the overall structure, through-holes penetrate the upper and lower surfaces of the carrier plate, forming a complete interlayer geometric reference. This ensures that the multilayer circuits always use the same axis as the alignment reference during exposure, drilling, and lamination, fundamentally eliminating the cumulative errors caused by independent interlayer targets. The first and second blind holes, respectively located on the upper and lower sides, are arranged coaxially with the through-holes to form a stepped optical recognition area. This allows the exposure machine to obtain a high-reflectivity signal from either side, avoiding the problems of low contrast and non-connected blind hole references in traditional through-hole recognition. The stepped design, where the through-hole diameter is smaller than the blind hole diameter, effectively blocks energy interference from the upper and lower processing sides, preventing thermal damage to the other side during laser processing, thus maintaining the integrity and clarity of the double-sided target edges.

[0019] The limited blind aperture rounded corner transition design makes the laser focal spot energy distribution more uniform, avoids local ablation and cracking at sharp corners, and enhances the mechanical stability and recognition smoothness of the aperture. At the same time, it forms a natural optical reflection diffusion effect in the stepped transition area, which is beneficial for the exposure machine imaging algorithm to recognize the target edge.

[0020] The energy attenuation transition zone formed at the connection between the defined through-hole and blind-hole, by adjusting the laser power distribution during processing, allows for smooth energy attenuation between the hole wall and the hole bottom. This not only reduces micro-steps and ablation pits at the interface, but also makes the surface tension and thermal stress gradient of the hole wall more uniform, significantly improving the geometric consistency and long-term stability of the interlayer target.

[0021] A reflective layer or copper plating is placed at the bottom of the blind hole, so that the target forms a highly reflective area under the imaging system of the exposure machine, which significantly improves the recognition signal-to-noise ratio and contrast. At the same time, the copper plating layer can also form a good conductive contact interface in subsequent electroplating or etching processes, enhancing structural stability and moisture resistance.

[0022] The processing method establishes a coaxial coordinate system to precisely locate the target center point, ensuring strict concentricity between the blind holes and through holes on both sides, thus eliminating the eccentricity problem caused by traditional independent processing. This method applies different laser energies in stages to process through holes and blind holes, achieving independent control of high-precision through-hole and surface recognition areas, with a wide process window and strong fault tolerance.

[0023] By employing a multi-turn spiral scanning strategy with decreasing energy, the energy is moderately increased near the center of the through hole and gradually decreased away from the through hole. This results in an energy distribution in the transition zone that is "generally decreasing from the outside to the inside with a slight upward arch at the edge," achieving a natural energy decay transition. The hole wall has no obvious steps or overheating marks, thus ensuring a smooth connection between through holes and blind holes and repeatable processing.

[0024] The reflective layer formation process achieves a dense metal film through plasma cleaning, surface activation, and physical vapor deposition. After annealing, it is stably bonded to the substrate surface at the bottom of the hole under an inert atmosphere, forming a mirror-like area with high reflectivity and resistance to chemical corrosion, further improving optical recognition accuracy and long-term process reliability. Overall, this invention achieves a balance between through-hole penetration accuracy, double-sided recognition contrast, and laser processing tolerance in structural design and process control, which can significantly reduce the interlayer misalignment defect rate of IC substrates and improve production line alignment efficiency and batch stability. Attached Figure Description

[0025] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the through-hole target structure without an energy attenuation transition region in the embodiment. Figure 2 This is a schematic diagram of the energy attenuation transition region provided in the through-hole target structure of the embodiment. Figure 3 This is a step diagram of the processing method of the through-hole target structure in the embodiment.

[0027] In the figure, 1 is a through hole; 2 is the first blind hole; 3 is the second blind hole; and 4 is the energy attenuation transition zone. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1 and Figure 2 As shown, the present invention provides a stepped through-hole target structure for IC carrier boards, including through-hole 1 disposed in the carrier substrate and first blind hole 2 and second blind hole 3 located on both sides of the carrier board. Through hole 1 penetrates the upper and lower surfaces of the carrier plate. First blind hole 2 and second blind hole 3 are located on the upper and lower surfaces of the carrier plate, respectively, and are both coaxially arranged with through hole 1. The diameter of through hole 1 is smaller than the diameters of the first blind hole 2 and the second blind hole 3. Through hole 1, the first blind hole 2, and the second blind hole 3 are coaxially arranged. The first blind hole 2 and the second blind hole 3 are used for optical alignment identification of the exposure machine, and the through hole 1 is used for interlayer geometric reference penetration.

[0030] In practical implementation, the IC substrate can be made of BT resin-based or ABF resin-based materials. A through-hole 1 is machined in the center of the substrate using high-precision laser drilling equipment. Then, a first blind via 2 and a second blind via 3 are sequentially machined on the top and bottom sides using relatively low laser power. The machining sequence of through-hole 1 can be either through-hole 1 followed by blind vias or vice versa, depending on the specific equipment and layer stack-up structure. During machining, an automatic focusing system is used to establish the center point coordinates of through-hole 1, and the laser machining paths on the top and bottom sides are automatically aligned to achieve strict coaxial arrangement. After completion, microscopic inspection confirms that the center deviation of the top and bottom blind vias is less than 20μm, thus ensuring a uniform geometric reference for the multilayer circuit during exposure.

[0031] In some embodiments, the diameter of the through hole 1 is 0.8 to 1.2 mm, and the diameters of the first blind hole 2 and the second blind hole 3 are 1.4 to 1.8 mm.

[0032] This size range balances interlayer connectivity with optical recognition performance. The through-hole 1 size is controlled at approximately 1mm, achieving high-precision penetration while maintaining the integrity of the substrate structure. The blind hole diameter is slightly larger than through-hole 1, providing a wider reflective surface for the exposure machine's recognition area and higher contrast. In actual testing, when using a combination of 1.0mm through-hole 1 and 1.6mm blind hole, the exposure machine's alignment accuracy improved by approximately 20%, and the recognition failure rate decreased by more than 50%. This aperture combination is also suitable for substrates of varying thicknesses (e.g., 80μm–200μm), ensuring stable compatibility with multilayer stacking conditions and adaptability to mass production.

[0033] In some embodiments, please refer to Figure 2 As shown, an energy attenuation transition zone 4 is provided at the connection between the hole wall of the through hole 1 and the blind hole, and the energy attenuation transition zone 4 has a smooth arc-shaped profile.

[0034] During processing, the energy attenuation transition zone 4 is achieved through graded laser energy control. High energy is used at the outer edge of the blind hole to ensure thorough removal, while the energy is gradually reduced near the edge of the through hole 1 to prevent abrupt changes in the hole wall. To eliminate sharp-angle steps, the energy is slightly increased near the edge of the through hole 1 to create a slight transition ablation, resulting in a smooth arc-shaped connection. Scanning microscopy reveals that the surface roughness Ra of the transition zone is approximately 0.2–0.3 μm, and the hole wall is continuous and crack-free. This arc-shaped connection morphology reduces shadow interference in the optical imaging of the exposure machine, resulting in continuous target image edges and clear features, making it suitable for high-precision exposure identification of multilayer boards.

[0035] In some embodiments, the bottom surfaces of the first blind hole 2 and the second blind hole 3 are provided with a reflective layer and / or a copper plating layer.

[0036] In practice, the bottom of the blind vias can first be plasma-cleaned and surface-activated, followed by the deposition of a metal reflective layer via physical vapor deposition. Materials such as aluminum, silver, nickel, and chromium can be used for the reflective layer, with a thickness controlled between 0.2 and 0.5 μm to achieve stable high reflectivity. If copper plating is used, a uniform copper layer of approximately 1 μm can be formed at the bottom of the vias. This layer not only enhances the intensity of reflected light but also provides a conductive interface for subsequent copper plating or electroplating. Reflectivity testing showed that the average reflectivity of the via bottom area after deposition reached over 90%, significantly improving the signal strength for the exposure machine. Long-term damp heat testing demonstrated strong adhesion of the plating layer, with no peeling, oxidation, or darkening, ensuring the stability of recognition during mass production.

[0037] In some embodiments, the edges of the openings of the first blind hole 2 and the second blind hole 3 are provided with an anti-corrosion protective layer or an anti-oxidation coating.

[0038] During implementation, a transparent protective film approximately 2–5 μm thick can be applied to the blind aperture and surrounding area using spraying or dip coating methods. This protective layer can be made of silicone-based anti-corrosion coating or fluoropolymer-based antioxidant materials. This coating effectively isolates the target from acid and alkali etching solutions during wet processing, preventing corrosion or oxidation discoloration of the aperture metal layer, thus maintaining the target's optical recognition contrast. After a 96-hour acid mist test, the protective layer remained intact without peeling, and the aperture reflection signal intensity attenuation was less than 2%. This anti-corrosion design maintains recognition stability even after long-term, repeated exposures and wet chemical treatments, ensuring reliable use of the target on mass production lines.

[0039] Please see Figure 3 As shown, in some embodiments, this application provides a method for fabricating a through-hole target structure for preparing the aforementioned stepped through-hole target structure for an IC substrate. The method includes the following steps: Step S1: Determine the center point of the target on the IC carrier and establish a coaxial coordinate system. Step S2: Use the first laser energy to process a through hole through the carrier plate along the center point to form a geometric reference hole through the upper and lower surfaces of the carrier plate; Step S3: Use the second laser energy to process the first blind hole on the upper surface of the carrier plate, and use the third laser energy to process the second blind hole on the lower surface of the carrier plate. Step S4: Perform surface metallization treatment on the bottom surfaces of the first blind hole and the second blind hole respectively; The surface metallization process employs a reflective layer formation process and / or a copper plating process.

[0040] In the actual processing, the target center point is first determined in a designated area of ​​the IC carrier board using an optical alignment system. The carrier board is fixed to the worktable using vacuum adsorption, and coaxial positioning is achieved through an upper and lower dual-lens system. After establishing the coaxial coordinate system, the control software uses the center point coordinates as the origin of all subsequent laser paths. Then, a high-energy laser is used to vertically irradiate from the center point, penetrating the carrier board to form a through-hole with rounded edges and straight walls. This through-hole serves as the interlayer geometric reference point, with a center error of less than ±10μm, ensuring the concentricity of the upper and lower layers. In subsequent layer stacking exposure or drilling processes, this through-hole can be directly used as the coordinate reference for the entire board, achieving precise stacking of multilayer circuits.

[0041] Blind holes are machined on both the upper and lower surfaces of through holes. A medium-power laser source is used during machining, and blind holes are machined on both sides of the through hole according to a preset coordinate system. The machining parameters for blind holes differ from those for through holes, with a focus on controlling energy distribution and scanning trajectory. During machining, the laser head scans spirally along a predetermined path, gradually converging from the outer edge inwards. By dynamically adjusting the scanning speed and laser pulse energy, the amount of material removed from the outer edge of the blind hole is maximized, while the amount removed from the inner edge gradually decreases, ultimately forming a hole with a smooth surface and uniform edges. This process effectively avoids the overlap of the heat-affected zones of the upper and lower blind holes, thereby preventing interlayer carbonization or delamination of the substrate and ensuring that the target holes on both sides are coaxial and have clear edges.

[0042] In some embodiments, during the blind hole processing in step S3, a spiral scanning path from the outside to the inside is adopted, and an energy attenuation transition zone is prepared at the connection between the through hole wall and the blind hole by setting a composite distribution of laser energy reduction and local gain control. Energy control follows the following relationship:

[0043] Where r represents the radial position currently scanned by the laser beam; Indicates the radius of the blind hole; Indicates the radius of the through hole; This indicates the starting radius for energy control near the through-hole. This is a safety clearance at the edge of the through hole; Indicates the normalized radius; This represents the cumulative surface energy per unit area at radius r; This represents the baseline energy distribution that decreases from the outside in. The accumulated surface energy at the outer edge of the blind hole. This is the energy decay ratio coefficient. The energy decay index is denoted by A; A represents the local energy gain amplitude near the edge of the via, used to compensate for edge transition. The Gaussian half-width represents the local energy gain.

[0044] During implementation, the laser control system sets an energy variation curve based on the aperture size, employing a power reduction mode with higher energy at the outer edge and lower energy at the inner edge. In the narrow region near the edge of the through-hole, the laser energy is moderately increased by approximately 5%–10% to compensate for material residue, thus forming a smooth transition zone at the interface. This transition zone is approximately 50 μm wide, with a continuous arc-shaped surface profile, free of obvious steps or ablation pits. Scanning electron microscopy observation shows that the interface between the through-hole wall and the bottom of the blind hole is smooth, with a surface roughness of less than 0.3 μm, and slight carbonization in the laser-affected area. Verification through multi-layer exposure shows that this transition zone effectively reduces optical shading effects, enabling the exposure machine to maintain a high recognition rate during image matching.

[0045] In some embodiments, the surface metallization process in step S4 employs a reflective layer formation process, specifically including the following steps: Step S4-1: Perform surface pretreatment on the bottom surfaces of the first blind hole and the second blind hole. The surface pretreatment includes removing oxides, removing impurity particles, and performing surface activation treatment on the bottom surfaces of the holes. Step S4-2: Deposit a thin film of reflective material on the pretreated bottom surface of the hole. The reflective material is selected from aluminum, silver, chromium, nickel and their binary or multi-element alloys, and is formed by physical vapor deposition or chemical vapor deposition process. Step S4-3: After deposition, perform annealing in a vacuum or inert atmosphere. The inert atmosphere is nitrogen or argon, the oxygen volume fraction is not greater than 50 ppm, the annealing temperature is controlled between 150°C and 250°C, and the time is between 15 minutes and 30 minutes.

[0046] In practice, after blind via fabrication, the carrier substrate is first ultrasonically cleaned to remove surface impurities, followed by low-temperature plasma treatment to activate the bottom surface of the vias. Subsequently, a metal reflective layer is deposited in a vacuum chamber using physical vapor deposition (PVD). The material can be aluminum or a nickel-chromium alloy, depending on compatibility with subsequent electroplating. After deposition, the carrier substrate is placed in an annealing furnace and heated to approximately 200°C in a nitrogen atmosphere for 20 minutes to release stress in the film and promote metal grain densification. The resulting reflective layer is approximately 0.3 μm thick, smooth, and firmly adhered, with a reflectivity exceeding 85% in the visible light band. Repeated wet processing and thermal cycling tests show no peeling or oxidation discoloration, maintaining long-term stable optical reflective performance. The target structure obtained through this process improves contrast by approximately 30% in the exposure machine's CCD system, effectively ensuring the alignment accuracy of multilayer circuits.

[0047] In some embodiments, this application provides a terminal, including: The memory is used to store the machining program for the through-hole target structure; A processor for executing steps of a method for fabricating a through-hole target structure when performing the stepped through-hole target structure for an IC substrate.

[0048] In some embodiments, this application provides a computer-readable storage medium that stores computer instructions. When a computer reads the computer instructions in the storage medium, the computer executes the processing method for the through-hole target structure.

[0049] It is understood that the systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer, which can be a personal computer, a laptop computer, a personal digital assistant, a tablet computer, a wearable device, or any combination of these devices.

[0050] In a typical configuration, a computer includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0051] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0052] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage, quantum memory, graphene-based storage media or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0053] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method of processing, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method of processing, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method of processing, article, or apparatus that includes said element.

[0054] It should be understood that although the terms first, second, third, etc., may be used to describe various information in one or more embodiments of this specification, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of one or more embodiments of this specification, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0055] The above description is merely a preferred embodiment of one or more embodiments of this specification and is not intended to limit the scope of one or more embodiments of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the protection scope of one or more embodiments of this specification.

Claims

1. A method for fabricating a through-hole target structure, used to prepare a through-hole target structure, characterized in that, The method includes the following steps: Step S1: Determine the center point of the target on the IC carrier and establish a coaxial coordinate system. Step S2: Use the first laser energy to process a through hole through the carrier plate along the center point to form a geometric reference hole through the upper and lower surfaces of the carrier plate; Step S3: Use the second laser energy to process the first blind hole on the upper surface of the carrier plate, and use the third laser energy to process the second blind hole on the lower surface of the carrier plate. In the blind hole processing in step S3, a spiral scanning path from the outside to the inside is adopted. By setting a composite distribution of laser energy reduction and local gain control, an energy attenuation transition zone is prepared at the connection between the through hole wall and the blind hole. Energy control follows the following relationship: Where r represents the radial position currently scanned by the laser beam; Indicates the radius of the blind hole; Indicates the radius of the through hole; This indicates the starting radius for energy control near the through-hole. This is a safety clearance at the edge of the through hole; Indicates the normalized radius; This represents the cumulative surface energy per unit area at radius r; This represents the baseline energy distribution that decreases from the outside in. The accumulated surface energy at the outer edge of the blind hole. This is the energy decay ratio coefficient. The energy decay index is denoted by A; A represents the local energy gain amplitude near the edge of the via, used to compensate for edge transition. This represents the half-width of the Gaussian distribution of the local energy gain; Step S4: Perform surface metallization treatment on the bottom surfaces of the first blind hole and the second blind hole respectively; Surface metallization treatment employs a reflective layer formation process and / or copper plating process; The through-hole target structure includes a through hole (1) disposed in the carrier plate substrate and a first blind hole (2) and a second blind hole (3) located on both sides of the carrier plate. The through hole (1) penetrates the upper and lower surfaces of the carrier plate. The first blind hole (2) and the second blind hole (3) are located on the upper and lower surfaces of the carrier plate, respectively, and are coaxial with the through hole (1). The diameter of the through hole (1) is smaller than the diameters of the first blind hole (2) and the second blind hole (3), and the first blind hole (2) and the second blind hole (3) are coaxially arranged; The first blind hole (2) and the second blind hole (3) are used for optical alignment identification of the exposure machine, and the through hole (1) is used for interlayer geometric reference penetration.

2. The processing method for the through-hole target structure according to claim 1, characterized in that, The diameter of the through hole (1) is 0.8 to 1.2 mm, and the diameters of the first blind hole (2) and the second blind hole (3) are 1.4 to 1.8 mm.

3. The processing method for the through-hole target structure according to claim 1, characterized in that, An energy attenuation transition zone (4) is provided at the connection between the hole wall of the through hole (1) and the blind hole. The energy attenuation transition zone (4) has a smooth arc-shaped profile.

4. The processing method of the through-hole target structure according to claim 1, characterized in that, The bottom surfaces of the first blind hole (2) and the second blind hole (3) are provided with a reflective layer and / or a copper plating layer.

5. The method for processing the through-hole target structure according to any one of claims 1-4, characterized in that, The edges of the first blind hole (2) and the second blind hole (3) are provided with an anti-corrosion protective layer or an anti-oxidation coating.

6. The processing method of the through-hole target structure according to claim 1, characterized in that, In step S4, the surface metallization treatment employs a reflective layer formation process, specifically including the following steps: Step S4-1: Perform surface pretreatment on the bottom surfaces of the first blind hole and the second blind hole. The surface pretreatment includes removing oxides, removing impurity particles, and performing surface activation treatment on the bottom surfaces of the holes. Step S4-2: Deposit a thin film of reflective material on the pretreated bottom surface of the hole. The reflective material is selected from aluminum, silver, chromium, nickel and their binary or multi-element alloys, and is formed by physical vapor deposition or chemical vapor deposition process. Step S4-3: After deposition, perform annealing in a vacuum or inert atmosphere. The inert atmosphere is nitrogen or argon, the oxygen volume fraction is not greater than 50 ppm, the annealing temperature is controlled between 150°C and 250°C, and the time is between 15 minutes and 30 minutes.

7. A terminal, characterized in that, include: The memory is used to store the machining program for the through-hole target structure; A processor is used to execute the machining program of the through-hole target structure to implement the steps of the machining method of the through-hole target structure as described in claim 1.

8. A computer-readable storage medium, characterized in that, The storage medium stores computer instructions. When the computer reads the computer instructions from the storage medium, the computer executes the processing method of the through-hole target structure as described in claim 1.

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