A coreless IC carrier structure sharing x-ray targets and a method of manufacturing the same

Abstract

The application relates to the field of semiconductor packaging, and provides a coreless IC carrier plate structure sharing an X-ray target point and a manufacturing method thereof, which comprises the following steps: manufacturing an X-RAY target pad on the upper surface of the inner layer of the carrier plate, the target pad being completely covered in the exposed dry film protection area; implementing edge sealing in a 0.5mm area around the X-RAY drilling target position, forming a sealed edge at a position 3mm inward from the plate edge, so that the carrier copper foil and the temporary core layer copper foil are completely fused; based on the target pad on the upper surface of the inner layer, the drilling target is positioned at a position 5-8mm offset from the center of the target pad and outside the plate dismounting line through X-RAY identification, and a through hole arranged in a triangular shape is drilled as a positioning reference; and mechanical plate dismounting is performed at a position 2-6mm inside the edge sealing line. The manufacturing method provided by the application cancels the secondary drilling process for the drilling target area before plate dismounting, and compared with the traditional process, the process flow time is reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging, and in particular to a coreless IC substrate structure with shared x-ray target points and its fabrication method. Background Technology

[0002] In the manufacturing process of coreless IC substrates, traditional target drilling, edge sealing, and board removal processes present numerous interconnected problems. Regarding X-ray target drilling, on the one hand, the target hole placement does not fully consider the characteristics of coreless substrates, often being located within the board removal line. During lamination, these holes are susceptible to mechanical stress and vibration, leading to breakage and deformation of the circuitry around the drilled holes. This increases drilling workload and severely impacts product quality. On the other hand, the multiple lamination, positioning, and drilling operations on high-layer boards complicate the target drilling process, increasing the probability of human error. Furthermore, improper edge sealing after target drilling allows chemicals to seep into the board during subsequent processes, causing electrical defects such as interlayer short circuits.

[0003] During the board removal process, numerous destructive target holes require laser edge sealing, consuming significant equipment time and manpower, increasing production costs, and raising product risk due to excessive edge sealing locations. Furthermore, secondary drilling of the target area is often necessary before board removal, which adds extra production time, equipment wear and tear, and introduces error sources such as hole position deviations, further impacting product quality and production efficiency. These problems severely restrict the production quality and efficiency of coreless IC carrier boards and urgently need to be addressed. Summary of the Invention

[0004] The main objective of this invention is to overcome the aforementioned defects in the prior art and provide a coreless IC carrier board structure with shared x-ray target points and its manufacturing method. This addresses the problems in traditional processes, such as unreasonable target hole settings, complex target drilling process, high risk of chemical infiltration, cumbersome board disassembly process, and large workload of edge sealing, thereby simplifying the process, reducing costs, and improving product quality.

[0005] The present invention adopts the following technical solution:

[0006] A method for fabricating a coreless IC substrate with a shared x-ray target includes the following steps:

[0007] Target design and fabrication: X-RAY target pads are fabricated on the inner layer of the carrier board, and the X-RAY target pads completely cover the protection area of ​​the exposed dry film.

[0008] Local edge sealing protection: Edge sealing is implemented in a 0.5mm area around the X-RAY drill target position, and a sealed edge is formed 3mm inward from the edge of the board, so that the carrier copper foil and the temporary core layer copper foil are completely fused.

[0009] X-RAY Drill Target Positioning: Based on the inner layer upper surface target pad, the drill target is identified and positioned 5~8mm off the center of the target pad and outside the board removal line by X-RAY, and three through holes arranged in a triangle are drilled as positioning references.

[0010] Panel removal: Mechanically remove the panel 2-6mm inside the edge banding line.

[0011] Specifically, the edge sealing is achieved by laser melting with a laser energy of 12W and a scanning speed of 200mm / s, and the edge sealing covers both the upper and lower layers of the drilled area.

[0012] Specifically, the X-RAY drill target parameters include: voltage 130–150kV, current 5–8mA, drilling speed 100,000–120,000rpm, and feed rate 1–3m / min.

[0013] Specifically, the target pattern is created using the MSAP process, and the exposed dry film completely covers the target pattern.

[0014] Specifically, the plate removal parameters include: tool speed 30,000–40,000 rpm, feed rate 50–100 mm / min; depth of cut 0.05–1.5 mm, and vacuum adsorption pressure 0.1–0.3 MPa.

[0015] Specifically, the X-RAY target pattern is a circular structure with a diameter of 2 to 4 mm and a pad thickness of 0.015 to 0.5 mm.

[0016] Specifically, three through holes arranged in a triangle are drilled as positioning references. The through holes are formed by laser processing with a diameter of 2 to 4 mm and a depth of 0.3 to 2 mm, with the center position of the drill target as the reference.

[0017] This invention also provides a coreless IC substrate structure with a shared x-ray target, comprising:

[0018] Inner target structure: X-RAY target pads are set on the upper surface of the inner layer of the carrier board and are completely covered by the exposed dry film;

[0019] Local edge sealing body: A rectangular or circular edge sealing structure that surrounds a 0.5mm area around the X-RAY drill target position, wherein the drill target position is offset from the center of the target pad by 5~8mm and is located outside the board removal line;

[0020] Edge sealing area: A continuous sealed rectangular edge sealing area located 3mm from the edge of the board, which integrates the carrier copper foil and the temporary core layer copper foil;

[0021] Positioning hole group: 3 through holes arranged in a triangle, which are drilled according to the position of the drill target.

[0022] Specifically, the partial sealing body is formed by laser melting, and the melting depth of the material covers both the upper and lower layers of the drilled area.

[0023] Specifically, the transmittance of the X-RAY target pad is ≥85%.

[0024] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. A method for fabricating a coreless IC carrier board with shared x-ray targets, comprising the following steps: Target design and fabrication: X-ray target pads are fabricated on the upper surface of the inner layer of the carrier board, the X-ray target pads completely covering the exposure dry film protection area; Local edge sealing: Edge sealing is implemented in a 0.5mm area around the X-ray target location, and a sealed edge is formed 3mm inward from the board edge, so that the carrier copper foil and the temporary core layer copper foil are completely fused; X-ray target positioning: Based on the target pads on the upper surface of the inner layer, the target is identified by X-ray and positioned 5-8mm off the center of the target pad and outside the board removal line, and three through holes arranged in a triangle are drilled as positioning references; Board removal operation: Mechanical board removal is performed 2-6mm inside the edge sealing line; The fabrication method provided by this invention eliminates the secondary drilling process for the target area before board removal, reducing the process time compared with traditional processes;

[0026] 2. The method provided by this invention reduces the number of drill target edge bandings, lowers the cost of edge banding materials and equipment wear and tear, and also reduces product scrap due to improper disassembly, thus saving production costs.

[0027] 3. The method provided by this invention reduces the rate of chemical penetration defects and the rate of plate breakage, effectively improving product quality and reducing product scrap caused by electrical defects and plate breakage; it also improves the alignment accuracy between layers. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of laser edge sealing at the X-ray target position of a coreless IC carrier board provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the process for fabricating a circuit board using a shared x-ray target scheme, provided in an embodiment of the present invention.

[0030] Figure 3 This is a schematic diagram of the first pressing of a drill target at a reference target position in multiple pressing operations, provided by an embodiment of the present invention, using a shared x-ray target point scheme.

[0031] Figure 4This is a schematic diagram of the second pressing of the drill target at the location of the reference target in multiple pressings, provided by an embodiment of the present invention, using a shared x-ray target point scheme.

[0032] Among them: 1. X-RAY drilling position; 2. X-RAY target pad; 3. Exposure dry film; 4. Depaneling line; 5. Laser edge sealing. Detailed Implementation

[0033] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0034] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] In existing technologies, the manufacturing process of coreless IC substrates suffers from interference between the drilling target positioning and the board removal process. Traditional methods place the X-ray drilling target holes within the board removal line, leading to mechanical stress during the lamination stage causing circuit breakage. Furthermore, multiple drilling operations increase process complexity and error risk. Inadequate edge sealing can cause chemical seepage, resulting in interlayer short circuits. The secondary processing in the board removal stage further reduces efficiency and introduces deviations.

[0036] Therefore, this application proposes a technical solution to fabricate an X-RAY target pad 2 on the inner layer of the carrier board that completely covers the exposed dry film protection area, wherein the exposed dry film protection area is the area framed by the exposed dry film 3; to implement local edge sealing protection around the drilling target position, and at the same time form a sealed edge at the distance from the board edge; to perform offset positioning based on the target pad and drill positioning through holes arranged in a triangle; and to perform board disassembly operation inside the edge sealing line.

[0037] The exposed dry film protection area refers to the anti-etching layer covering the target pads, which can be formed by applying photoresist and then exposing and developing it. Its function is to protect the target from subsequent etching chemicals. Local edge sealing protection includes two functional areas: a ring-shaped protective strip around the drill target position and a continuous sealing strip extending along the board edge. Copper foil interlayer bonding is achieved through hot pressing or laser melting to prevent chemical penetration. Offset positioning refers to maintaining a preset distance between the drill target center point and the geometric center of the target pad. Coordinate transformation is achieved through an X-ray image recognition system to avoid the internal stress of the board removal line affecting drilling accuracy. Triangularly arranged through-holes form a spatial positioning reference, and a three-point positioning method is used to improve the alignment consistency of multi-station processing.

[0038] Specifically, when fabricating target pads on the inner layer of the carrier board, a pattern transfer process is used to create precise positioning marks, and dry film coverage ensures the integrity of the target points during the etching process. Edge sealing is handled in sections; the area around the drilled target is sealed to form an isolation zone, and the board edge is sealed to strengthen the structural bonding. After the X-ray recognition system reads the target pad coordinates, it automatically calculates the offset to generate the drilled target coordinates, and the drilled triangular through-holes form a three-dimensional positioning reference. The board disassembly operation is performed along the inner side of the edge sealing structure, using mechanical cutting to separate the carrier board units while preserving the complete edge sealing layer.

[0039] Traditional methods place the drill target hole directly within the disassembly line, causing mechanical stress during the lamination process to act directly on the drilled area. This solution uses a spatial separation design to position the drill target away from the stress concentration area during disassembly, while a composite edge-sealing structure provides double protection. Existing technologies require multiple drilling operations to correct positioning errors, while this solution uses triangular through-holes to create a three-dimensional reference, reducing the number of rework operations.

[0040] This invention proposes a method for fabricating a coreless IC substrate with a shared x-ray target, comprising the following steps:

[0041] S1. Target design and fabrication: X-RAY target pad 2 is fabricated on the upper surface of the inner layer of the carrier plate, and the X-RAY target pad 2 completely covers the protection area of ​​the exposed dry film.

[0042] Abandoning the traditional approach of setting target patterns on multiple layers, X-ray target patterns are only created on the inner upper surface. The inner upper surface offers good stability and strong protection in the coreless IC substrate structure, and is not easily affected by external interference in subsequent processes. It provides a stable physical environment for the target patterns, ensuring accurate positioning and clear patterns during X-ray drilling.

[0043] Exposure dry film 3 provides full coverage protection: The target pattern is placed within the area completely covered by the exposure dry film 3. During exposure, the dry film adheres tightly to the circuit board surface, blocking the erosion of chemicals such as etching solutions and electroplating solutions, buffering external mechanical stress impacts, ensuring the integrity of the target pattern, and also facilitating subsequent pattern transfer, improving drilling accuracy and reliability.

[0044] MSAP process: conventional lamination, laser drilling, and high-density circuit processing.

[0045] MSAP process refers to the semi-additive process, which can be achieved by combining patterned electroplating and etching. After the desired pattern is formed by electroplating, excess copper layer is removed. The high resolution of this process is used to control the accuracy of the target pattern and avoid side etching or linewidth deviation.

[0046] Among them, the dry film 3 completely covers the target pattern, which means that the dry film coverage area extends beyond the edge of the target pattern. Specifically, it can be achieved by photoresist coating and exposure and development processes. By forming a continuous and gapless physical isolation layer, it prevents the electroplating or etching solution from contacting the target area.

[0047] Specifically, the MSAP process forms the target pattern substrate by electroplating a copper layer, and then removes the copper layer in the non-patterned areas by etching. Because the thickness of the electroplated copper layer is controllable and the etching process has minimal impact on the pattern edges, the size and shape of the target pattern can be precisely controlled, reducing positioning reference offsets caused by process errors. After development, the exposed dry film 3 completely covers the target pattern, forming a sealed protective layer to prevent chemicals from seeping into the target area in subsequent processes, causing structural corrosion or contamination. It also prevents areas not covered by the dry film from being accidentally removed during etching, ensuring the integrity of the target pattern.

[0048] S2, Local edge sealing protection: Edge sealing is implemented in a 0.5mm area around the X-RAY drill target position, and a sealed edge is formed 3mm inward from the edge of the board, so that the carrier copper foil and the temporary core layer copper foil are completely fused; The edge sealing in the embodiment is achieved by laser, and 5 in Figure 1 is the specific position of laser edge sealing.

[0049] Partial edge sealing design: Before X-ray drilling, the drilling location is sealed with a rectangular or circular edge. The edge sealing size is customized according to the size and shape of the drilled hole, ensuring complete coverage of the 0.5mm area around the drilled hole, with a margin to accommodate positional offsets or process errors. This ensures that even with slight changes in the drilled hole position during subsequent wet processes such as etching and electroplating, the edge sealing effectively prevents chemical seepage, protecting the internal circuitry of the circuit board.

[0050] Board edge sealing design: A sealed rectangular edge is made 3mm inward from the board edge to ensure that the carrier copper foil and the temporary core copper foil are completely fused together, so that the layers will not separate in subsequent processes.

[0051] Five parameters for laser edge sealing: Laser energy 12W, which affects the melting and solidification of the edge sealing material. Adjusting the laser energy release ensures that the edge sealing material is fully melted and bonded to the substrate; Scanning speed 200mm / s, which determines the coverage speed and uniformity of the edge sealing material; Edge sealing consists of two layers, top and bottom.

[0052] The laser energy of 12W refers to the laser output power parameter, which can be achieved by adjusting the laser current or modulating the pulse width. This energy range ensures sufficient fusion of the copper foil while preventing overheating damage to the substrate. The scanning speed of 200mm / s refers to the speed at which the laser beam moves across the processing plane. This can be achieved by setting the motion axis interpolation parameters through the CNC system. This speed works in conjunction with the laser power to balance processing efficiency and melt quality.

[0053] Among them, the sealing of the upper and lower layers of the drilling area refers to the simultaneous melting and sealing of the upper and lower copper foil at the drilling location. Specifically, it can be processed synchronously by a dual-head laser processing system to form a three-dimensional sealing structure that penetrates the thickness of the plate.

[0054] Specifically, during edge sealing around the X-ray drilling target, the laser beam scans the copper foil along a preset path. At 12W energy, the carrier copper foil and the temporary core layer copper foil melt and interpenetrate, forming a seamless metallurgical interface. With a scanning speed set to 200mm / s, the single-pass scanning time is reduced to milliseconds, significantly improving processing efficiency. Through simultaneous melting of the upper and lower layers, a double-layer copper foil fusion structure is formed in the drilling area, completely sealing the interlayer medium gaps and blocking the path of chemical penetration from the board surface or between layers.

[0055] S3, X-RAY Drill Target Positioning: Based on the inner layer upper surface target pad, the drill target is identified by X-RAY and positioned 5~8mm off the center of the target pad and outside the board removal line 4. Three through holes arranged in a triangle are drilled as positioning references.

[0056] Precise Target Reading and Positioning: Utilizing advanced X-ray drilling equipment, a high-resolution image of the target point on the inner upper surface is read using precise image recognition algorithms and a precision mechanical positioning system. The target point's position is then precisely matched with the equipment's internal preset coordinate system. Based on the design requirements of the coreless IC substrate and subsequent process requirements, the target point is fixed at a certain distance (generally 5-8mm) beyond the disassembly line 4 before drilling. This distance is determined by comprehensively considering factors such as substrate material characteristics, thickness, mechanical strength, disassembly stress distribution range, and subsequent drilling positioning accuracy requirements. This avoids the influence of disassembly stress, and the hole position drilled based on this target point meets the product's electrical and mechanical performance requirements.

[0057] Triangular positioning drilling strategy: Based on a fixed target position, three through holes arranged in a stable triangular structure are drilled using an X-ray drilling device. Utilizing the stability of the triangle, a reliable positioning reference is provided for subsequent mechanical or laser drilling. The drilling equipment can quickly and accurately determine the starting position and direction of the drilling based on these three through holes, ensuring the relative positional accuracy of the holes, avoiding problems such as hole position deviation and uneven hole spacing, and improving product processing accuracy and quality stability.

[0058] X-RAY drill parameters: voltage set to 130-150kV to ensure X-rays penetrate the coreless substrate and obtain clear target images; current controlled at 5-8mA to adjust X-ray emission intensity and ensure imaging quality; drilling speed of 100,000-120,000rpm to ensure drilling efficiency and quality and prevent drill bit overheating and damage; feed speed of 1-3m / min to ensure smooth borehole walls without burrs.

[0059] The voltage range of 130-150kV refers to the operating voltage range of the X-ray generator, which can be achieved using a high-frequency inverter-type high-voltage generator. This voltage range allows for clear image penetration through the carrier material while avoiding excessive energy consumption due to excessive voltage. The current range of 5-8mA refers to the operating current range of the X-ray tube, which can be achieved using a grid-controlled X-ray tube. This current range ensures that the image resolution meets positioning requirements while controlling the cathode electron emission to reduce heat accumulation. The drilling speed range of 100,000-120,000rpm refers to the rotational speed of the spindle drive system, which can be achieved using an air-bearing high-speed electric spindle. This speed range matches the cutting characteristics of copper foil to reduce burr generation. The feed rate of 1-3m / min refers to the axial movement rate of the drill bit, which can be achieved using a linear motor drive system. This speed range, combined with the spindle speed, forms the optimal combination of cutting parameters.

[0060] Specifically, during the X-ray imaging stage, the combination of 130-150kV voltage and 5-8mA current allows for control of the equipment's thermal load while ensuring image contrast. Once image positioning is complete, a dynamic balance is achieved between the spindle speed of 100,000-120,000rpm and the axial feed rate of 1-3m / min. This ensures that the drill bit completes effective cutting within a unit of time while keeping the contact time between the cutting edge and the material within a reasonable range. This parameter combination, through precise control of the relationship between energy input and mechanical motion, allows the drill bit to maintain cutting stability even at high speeds, avoiding vibration and deviation caused by excessively high speeds, while also preventing repeated friction on the machined surface due to excessively low feed rates.

[0061] This application further proposes that during the X-RAY drill target positioning process, three through holes arranged in a triangle are drilled as positioning references. The through holes are formed with a diameter of 2 to 4 mm and a depth of 0.3 to 2 mm by laser processing, with the center position of the drill target as the reference.

[0062] Among them, the triangular arrangement of through holes refers to the distribution of three through holes in the geometric shape of an equilateral or isosceles triangle. Specifically, the coordinates of the holes can be determined by a laser positioning system, and the spatial constraint relationship formed by the vertices of the triangles enhances the stability of the positioning reference.

[0063] Among them, through holes formed by laser processing refer to the formation of hole structures by ablation of materials using a high-energy laser beam. Specifically, this can be achieved by using a pulsed laser in conjunction with a focusing optical system. The quality of the hole wall and the accuracy of the hole diameter can be controlled by adjusting the laser energy density and pulse frequency.

[0064] The diameter of the through hole is 2 to 4 mm, which refers to the size range of the inner diameter of the hole. This can be achieved by adjusting the diameter of the laser spot and the overlap rate of the processing path, so as to ensure the accuracy of the reference identification while avoiding the reduction of structural strength caused by excessively large hole diameter.

[0065] The through-hole depth of 0.3 to 2 mm refers to the vertical distance from the processed surface to the bottom of the hole. This can be achieved by controlling the number of laser processing cycles or the depth of a single ablation, thus meeting the positioning requirements of multilayer boards while preventing excessive processing from damaging the underlying circuitry.

[0066] Specifically, after X-ray identification of the target center, a spatial positioning reference is established using three through-holes arranged in a triangle. During laser processing, a high-energy-density laser beam removes material layer by layer along a predetermined path, forming a through-hole structure with smooth walls. The geometric relationship between the vertices of the triangles provides multi-directional constraints for subsequent pressing and drilling processes, effectively offsetting the cumulative errors caused by interlayer misalignment. The diameter and depth parameters of the through-holes are matched using laser process parameters, ensuring that the hole structure can withstand the thermal pressing in subsequent processes while avoiding mechanical stress that could cause cracks in the hole walls.

[0067] This application solves the risk of interlayer short circuits caused by poor hole wall quality in traditional drill-target reference structures, reduces the cumulative error of hole position during multiple pressing processes, and avoids physical damage to the coreless carrier plate structure caused by mechanical drilling through laser processing technology, thereby improving the processing efficiency and structural reliability of the positioning reference.

[0068] This application further proposes a coreless IC carrier board structure with shared x-ray target points, including an inner layer target point structure with an X-ray target pad 2 disposed on the upper surface of the inner layer of the carrier board and completely covered by an exposed dry film 3, a rectangular or circular sealing edge structure surrounding a 0.5mm area around the X-ray target position, a continuous sealed rectangular sealing edge area located 3mm away from the edge of the board, and a positioning hole group consisting of three through holes arranged in a triangle.

[0069] The inner target structure refers to the X-ray identification reference completely covered by the exposed dry film 3. This can be achieved using a semi-additive process to create copper pads, avoiding stress concentration caused by target exposure through dry film coverage. The local sealing layer refers to the protective boundary formed around the drill target location, which can be achieved by laser melting of copper foil to form a continuous closed ring. Limiting the sealing area prevents chemical penetration while reducing the processing area. The board edge sealing area refers to the interface between the carrier and the temporary core layer, which can be achieved by laser melting to fuse copper layers together to form a sealed structure. Continuous rectangular sealing enhances the interlayer bonding strength. The positioning hole group refers to the spatial positioning reference, which can be achieved by laser drilling to form a three-point support structure, using a triangular arrangement to construct a stable geometric coordinate system.

[0070] Specifically, the target pads covered by the exposed dry film 3 are configured as X-ray identification references, avoiding the deformation of traditional exposed target points during the lamination process. The drill target position is limited to the area outside the depaneling line 4, and the working range of the depaneling tool is avoided by an outward offset of 5-8mm. The local edge sealing body forms a 0.5mm wide annular protective band, reducing the processing area to the necessary range while ensuring sealing. The edge sealing area achieves metallurgical bonding between the carrier and the temporary layer through a 3mm wide continuous fusion structure, forming a rigid support resistant to lamination stress. The three through holes form a spatial positioning reference in a triangular layout, using the principle of three points determining the plane to eliminate single-point positioning errors.

[0071] Compared to existing technologies, traditional structures place the drill target hole within the disassembly line, causing the positioning reference to be damaged during tool cutting. This solution, however, moves the drill target position outward, removing the positioning reference from the disassembly area. Existing technologies use full-circumference edge sealing, consuming significant processing time. This solution reduces the processing area by over 80% by limiting the local edge sealing area. Traditional single-point positioning holes are prone to cumulative errors; this solution improves positioning accuracy by establishing a spatial coordinate system using a group of triangular through holes.

[0072] Through the above technical solution, this application effectively prevents mechanical damage to the positioning reference during the disassembly operation, avoids interlayer short circuit defects caused by chemical penetration, reduces the equipment running time required for edge sealing processing, and improves the interlayer alignment accuracy to the micron level through the three-point positioning structure.

[0073] like Figure 1 This is a schematic diagram of laser edge sealing at the X-RAY drilling target position on a coreless IC carrier board. 1 represents the X-RAY drilling position, 2 represents the X-RAY target pad, 3 represents the exposed dry film, 4 represents the board removal line, and 5 represents the laser edge sealing.

[0074] S4 panel removal operation: Mechanically remove the panel 2-6mm inside the edge banding line.

[0075] Removal location: 2~6mm less than the edge banding line on one side, leaving space for X-RAY drilling through holes.

[0076] Disassembly parameters: Tool speed 30,000-40,000 rpm to ensure tool cutting performance and improve disassembly efficiency; feed rate 50-100 mm / min to control disassembly speed and avoid excessive stress on the board; cutting depth 0.05–1.5 mm to accurately disassemble the coreless carrier board and protect the circuitry inside; vacuum adsorption pressure 0.1-0.3 MPa to fix the board through vacuum adsorption and prevent board warping.

[0077] The cutting tool rotation speed refers to the angular velocity driving the cutting tool, which can be achieved using a high-speed spindle motor. This speed range balances cutting efficiency and tool wear. The feed rate refers to the linear velocity of the tool along the cutting path, which can be adjusted using a servo control system. This speed range balances machining accuracy and production efficiency. The depth of cut refers to the vertical depth to which the tool penetrates the substrate material, which can be controlled by a precision guide mechanism. This depth range ensures complete separation of the board while avoiding damage to the substrate. The vacuum adsorption pressure refers to the negative pressure strength for fixing the substrate, which can be generated using a vacuum pump system. This pressure range achieves stable substrate positioning without indentation.

[0078] Specifically, in the depaneling process, the cutting tool rotates at a high speed of 30,000–40,000 rpm, coupled with a feed rate of 50–100 mm / min to maintain a uniform movement along the cutting path, ensuring a smooth cutting process. The depth of cut is controlled within the range of 0.05–1.5 mm, penetrating the board connection area through a layered, progressive cutting method. A vacuum adsorption system uses a pressure of 0.1–0.3 MPa to fix the substrate to the worktable, preventing displacement during processing. The coordinated control of these parameters ensures uniform cutting force distribution, reduces abnormal tool vibration, and avoids tool breakage or substrate delamination caused by sudden changes in cutting resistance.

[0079] like Figure 2 This is a schematic diagram of the process of manufacturing a circuit board using the solution of the present invention.

[0080] This application further proposes a coreless IC carrier board structure with shared x-ray target points, including an inner layer target point structure with an X-ray target pad 2 set on the upper surface of the inner layer of the carrier board and completely covered by the exposed dry film 3, a rectangular or circular sealing edge structure surrounding a 0.5mm area around the X-ray drill target position, a continuous sealed rectangular sealing edge area located 3mm away from the board edge, the drill target position being limited to the area outside the board removal line 4, the working range of the board removal tool being avoided by an outward offset of 5-8mm, and a positioning hole group consisting of 3 through holes arranged in a triangle.

[0081] The inner target structure refers to the X-ray identification reference completely covered by the exposed dry film 3. This can be achieved using a semi-additive process to create copper pads, avoiding stress concentration caused by target exposure through dry film coverage. The local sealing layer refers to the protective boundary formed around the drill target location, which can be achieved by laser melting of copper foil to form a continuous closed ring. Limiting the sealing area prevents chemical penetration while reducing the processing area. The board edge sealing area refers to the interface between the carrier and the temporary core layer, which can be achieved by laser melting to fuse copper layers together to form a sealed structure. Continuous rectangular sealing enhances the interlayer bonding strength. The positioning hole group refers to the spatial positioning reference, which can be achieved by laser drilling to form a three-point support structure, using a triangular arrangement to construct a stable geometric coordinate system.

[0082] Specifically, the target pads covered by the exposed dry film 3 are configured as X-ray identification references, avoiding the deformation of traditional exposed target points during the lamination process. The drill target position is limited to the area outside the depaneling line 4, and the working range of the depaneling tool is avoided by an outward offset of 5-8mm. The local edge sealing body forms a 0.5mm wide annular protective band, reducing the processing area to the necessary range while ensuring sealing. The edge sealing area achieves metallurgical bonding between the carrier and the temporary layer through a 3mm wide continuous fusion structure, forming a rigid support resistant to lamination stress. The three through holes form a spatial positioning reference in a triangular layout, using the principle of three points determining the plane to eliminate single-point positioning errors.

[0083] Traditional structures place the drill target hole within the disassembly line, causing the positioning reference to be damaged during tool cutting. This solution, however, moves the drill target position outward, removing the positioning reference from the disassembly area. Existing technology uses full-circumference edge sealing, consuming significant processing time; this solution greatly reduces the processing area by limiting the edge sealing region. Traditional single-point positioning holes are prone to cumulative errors; this solution improves positioning accuracy by establishing a spatial coordinate system using a group of triangular through holes.

[0084] By setting the drill target position to be limited to the area outside the disassembly line 4, and by shifting it outward by 5-8mm to avoid the working range of the disassembly tool, as well as the positioning hole group consisting of 3 through holes arranged in a triangle, the mechanical damage to the positioning reference caused by the disassembly operation is effectively prevented, the interlayer short circuit defect caused by chemical penetration is avoided, the equipment running time required for edge banding is reduced, and the interlayer alignment accuracy is improved to the micron level through the three-point positioning structure.

[0085] This application further proposes that the local sealing body is formed by laser melting, and the melting depth of the material covers the upper and lower layers of the drilled area.

[0086] Among them, the local sealing body refers to the physical barrier structure formed around the drilling area. Specifically, it can be achieved by using laser energy to act on the metal material to cause phase transformation and fusion, forming a continuous sealing interface through the metallurgical bonding of materials.

[0087] The melting depth covering the upper and lower layers of the drilling area refers to the sealing body simultaneously penetrating the carrier copper foil and the temporary core layer copper foil in the vertical direction. Specifically, the melting pool depth can be controlled by adjusting the laser power and the action time, so that the melting area can simultaneously penetrate into the two material layers adjacent to the drilling area.

[0088] Specifically, during laser melting around the drilled area, a high-energy laser beam acts on the interface between the carrier copper foil and the temporary core layer copper foil, causing a eutectic reaction between the two materials under thermal effects. As the molten metal cools, a dense alloy layer penetrates both layers, horizontally surrounding the drilled area and vertically completely sealing the gap between the two materials. By controlling the laser parameters, the depth of the molten area reaches the total thickness of the carrier copper foil and the temporary core layer copper foil, thus constructing a seamless protective structure in three-dimensional space.

[0089] In some specific implementations, the laser melting process can be performed using a pulsed laser, with the heat input controlled by adjusting the pulse frequency and duty cycle. The processing path can employ a helical scanning method to create a uniform annular sealing structure in the molten region.

[0090] By setting up localized edge sealing bodies that are melted by laser, the path of chemical solutions to penetrate into the drilling area through interlayer gaps in subsequent wet processes is effectively blocked, avoiding interlayer short-circuit defects caused by chemical residues, while improving the bonding reliability between the edge sealing structure and the substrate.

[0091] This application further proposes that the light transmittance of the target pad is not less than 85%.

[0092] Transmittance refers to the material's ability to allow X-rays to pass through. This can be achieved by using low-density metal alloys or reducing the thickness of the copper layer, for example, by controlling the thickness through adjusting the etching process of the copper foil. This parameter ensures that X-rays can penetrate the target pads and form clear imaging features, thus avoiding identification errors caused by material absorption or scattering.

[0093] Specifically, during X-ray drilling, when the transmittance reaches a set threshold, the X-ray imaging system can accurately capture the position information of the target pads, reducing positioning errors. High transmittance makes the target edge contours clearer in the image, avoiding drilling deviation caused by image blurring. Simultaneously, achieving the required transmittance indicates that the material density and thickness of the target pads meet process requirements, enabling effective sealing during subsequent edge sealing and preventing chemical penetration into interlayer gaps.

[0094] By setting the transmittance of the target pads to be no less than 85%, high-precision identification of the target position is achieved during X-ray drilling, reducing circuit damage caused by drilling deviation. At the same time, by improving the sealing effect, interlayer short circuits caused by chemical seepage are avoided, thereby improving the stability and yield of the coreless IC substrate process.

[0095] In addition, such as Figure 3-4 This is a schematic diagram of the position of the reference target after multiple pressings, where Figure 3 This is a schematic diagram of the first pressing of the drill target at the reference target position during multiple pressing using the shared x-ray target point scheme of the present invention. Figure 4 This is a schematic diagram of the second pressing of the drill target in multiple pressing reference target positions using the shared x-ray target point scheme of the present invention; after reading the target, move it outward by a fixed distance A (8mm) to the X-ray through hole outside the exposed dry film area; the second pressing drill target is in the same position as the first pressing. If the transmittance of the prepreg cannot be met after pressing more than 6 layers, the current outermost X-ray pad position can be reselected as the reference point, and the operation of the shared method of the present invention can be repeated.

[0096] 1. A method for fabricating a coreless IC carrier board with shared x-ray target points, comprising the following steps: Target point design and fabrication: X-ray target pads 2 are fabricated on the upper surface of the inner layer of the carrier board, the X-ray target pads 2 completely covering the exposure dry film protection area; Local edge sealing protection: Edge sealing is implemented in a 0.5mm area around the X-ray target position, and a sealed edge is formed 3mm inward from the board edge, so that the carrier copper foil and the temporary core layer copper foil are completely fused; X-ray target positioning: Based on the target pads on the upper surface of the inner layer, the target is identified by X-ray and positioned 5-8mm off the center of the target pad and outside the board removal line 4, and three through holes arranged in a triangle are drilled as positioning references; Board removal operation: Mechanical board removal is performed 2-6mm inside the edge sealing line; The fabrication method provided by this invention eliminates the secondary drilling process for the target area before board removal, reducing the process time compared with traditional processes.

[0097] 2. The method provided by this invention reduces the number of drill target edge bandings, lowers the cost of edge banding materials and equipment wear and tear, and also reduces product scrap due to improper disassembly, thus saving production costs.

[0098] 3. The method provided by this invention reduces the rate of chemical penetration defects and the rate of plate breakage, effectively improving product quality and reducing product scrap caused by electrical defects and plate breakage; it also improves the alignment accuracy between layers.

[0099] The above embodiments are illustrative of the principles and effects of the present invention and are not intended to limit the invention. Those skilled in the art can make modifications to the above embodiments without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be as set forth in the claims.

Claims

1. A method for fabricating a coreless IC substrate with a shared x-ray target, characterized in that, The method comprises the following steps: Target design and preparation: X-RAY target pads are prepared on the upper surface of the inner layer of the carrier plate, which are completely covered by the exposure dry film protection area; Local edge sealing: edge sealing is performed in the area 0.5 mm around the X-RAY drilling target position, and a sealed edge is formed 3 mm inward from the plate edge to completely fuse the carrier copper foil and the temporary core layer copper foil; X-RAY drilling target positioning: based on the target pads on the upper surface of the inner layer, the drilling target is positioned 5-8 mm away from the center of the target pad and outside the plate separation line through X-RAY identification, and three through holes arranged in a triangle are drilled as positioning reference; Plate separation operation: mechanical plate separation is performed 2-6 mm inside the edge sealing line.

2. The method of claim 1, wherein the method further comprises: The edge sealing is achieved by laser fusion, the laser energy is 12 W, and the scanning speed is 200 mm / s, and the edge sealing covers the upper and lower layers of the drilling area.

3. The method of claim 1, wherein the method further comprises: The X-RAY drilling target parameters include: voltage 130-150 kV, current 5-8 mA, drilling rotation speed 100,000-120,000 rpm, and feeding speed 1-3 m / min.

4. The method of claim 1, wherein the method further comprises: The X-RAY target pads are prepared by MSAP process, and the exposure dry film completely covers the X-RAY target pads.

5. The method of claim 1, wherein the method further comprises: The plate separation parameters include: tool rotation speed 30,000-40,000 rpm, feeding speed 50-100 mm / min, cutting depth 0.05-1.5 mm, and vacuum suction pressure 0.1-0.3 MPa.

6. The method of claim 1, wherein the method further comprises: The X-RAY target pad is a circular structure with a diameter of 2-4 mm, and the pad thickness is 0.015-0.5 mm.

7. The method of claim 1, wherein the method further comprises: Three through holes arranged in a triangle are drilled as positioning reference, the through holes are formed by laser processing with a diameter of 2-4 mm and a depth of 0.3-2 mm based on the drilling target center position.

8. A coreless IC carrier structure sharing an x-ray target, characterized by, It comprises: Inner layer target structure: X-RAY target pads arranged on the upper surface of the inner layer of the carrier plate, which are completely covered by the exposure dry film; Local edge sealing body: a rectangular or circular edge sealing structure surrounding the area 0.5 mm around the X-RAY drilling target position, which is 5-8 mm away from the center of the target pad and outside the plate separation line; Plate edge sealing area: a continuous sealed rectangular edge sealing located 3 mm from the plate edge to fuse the carrier copper foil and the temporary core layer copper foil; Positioning hole group: three through holes arranged in a triangle, which are drilled according to the drilling target position.

9. The coreless IC carrier structure sharing an x-ray target according to claim 8, wherein, The local edge sealing body is formed by laser fusion, and the material fusion depth covers the upper and lower layers of the drilling area.

10. The coreless IC carrier structure sharing an x-ray target according to claim 8, wherein, The light transmittance of the X-RAY target pad is ≥85%.

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