High-density circuit board for mini LED lamp set and manufacturing method thereof

Abstract

A manufacturing method of a high-density circuit board for a mini LED lamp set and the circuit board are provided to solve the problems of easy damage and low efficiency due to the thin board body, the method comprising: providing a temporary support plate, fixing a first conductive layer on the upper and lower surfaces through a peelable adhesive layer to form a support structure; drilling alignment marks and anti-layering structures on the support structure; stacking a dielectric layer and a second conductive layer on the upper and lower surfaces of the support structure in sequence to form an intermediate structure; manufacturing blind holes on the intermediate structure and etching alignment targets; manufacturing circuit patterns on the intermediate structure; stacking at least one additional dielectric layer and at least one additional conductive layer on the upper and lower surfaces of the intermediate structure in sequence to form a multi-layer structure; drilling laser holes in the multi-layer structure by using the alignment targets; removing the temporary support plate to obtain first and second sub-boards; and then performing electroplating and post-process treatment respectively. The present application can prevent processing damage and improve production efficiency.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board manufacturing technology, and in particular to a method for manufacturing a high-density circuit board for mini LED lamp sets, as well as a high-density circuit board for mini LED lamp sets. Background Technology

[0002] With the rapid development of display technology, mini LED (miniature light-emitting diode) has become an important choice for the next generation of high-definition displays. It uses smaller LEDs and more partitions to achieve image quality close to that of OLED (organic light-emitting diode) on the LCD (Liquid Crystal Display) architecture, while retaining the advantages of LCD such as long lifespan, no burn-in, and controllable cost.

[0003] Mini LED light clusters typically require high-density printed circuit boards (HDI boards) to achieve precise pad layouts and interconnections. These boards are often thin (e.g., less than 0.4 mm), presenting the following significant challenges when fabricated individually: First, because the sheet is too thin, it is prone to mechanical damage such as creases, tears, and pulling during processes such as pressing, drilling, and handling. In severe cases, it may even be pierced by positioning pins or punches, resulting in product scrap.

[0004] Secondly, thin sheets are difficult to process in large batches efficiently. Traditional single-piece processing methods require frequent loading and unloading, resulting in low equipment utilization. Furthermore, each sheet requires individual tooling, leading to low production efficiency.

[0005] Therefore, there is an urgent need for a method to manufacture high-density circuit boards for mini LED light groups that can prevent damage to thin boards during processing and improve processing efficiency. Summary of the Invention

[0006] This invention aims to solve the problems of creases, tears, stretching, and even penetration damage that occur during the processing of high-density circuit boards for mini LED light assemblies due to their thinness, as well as the low processing efficiency. It provides a method for manufacturing a high-density circuit board for mini LED light assemblies and the circuit board itself. A temporary support plate increases the rigidity of the thin board, preventing processing damage; double-sided synchronous production improves production efficiency; and a positioning target is used to achieve precise alignment of laser holes, ensuring the quality of high-density interconnects.

[0007] In a first aspect, the present invention provides a method for manufacturing a high-density circuit board for a mini LED lamp assembly, comprising the following steps: A temporary support plate is provided, and a first conductive layer is fixed to the upper and lower surfaces of the temporary support plate by a peelable adhesive layer to form a support structure; Alignment marks and anti-delamination structures are drilled into the support structure; A dielectric layer and a second conductive layer are stacked sequentially above and below the support structure and then pressed together to form an intermediate structure. Blind holes are fabricated on the intermediate structure, and alignment targets are simultaneously etched during the etching step of fabricating the blind holes. Create circuit patterns on the intermediate structure; At least one additional dielectric layer and at least one additional conductive layer are further stacked above and below the intermediate structure, and then laminated to form a multilayer structure; Alignment is performed using the alignment target, and laser holes are drilled in the multi-layer structure; Remove the temporary support plate to obtain the first sub-plate and the second sub-plate; Electroplating and subsequent processing are performed on the first and second sub-boards.

[0008] Furthermore, the temporary support plate is an insulating carrier plate or a metal carrier plate; the peelable adhesive layer is a micro adhesive layer or a heat-peelable adhesive layer.

[0009] Furthermore, the anti-delamination structure consists of explosion-proof holes distributed around the edge of the plate, the diameter of the explosion-proof holes being 0.2mm to 1.0mm, and the distance between the explosion-proof holes and the edge of the plate being 1.0mm to 5.0mm.

[0010] Furthermore, the method also includes: The panel dimensions are extended outward to form an extension area, the anti-delamination structure is set in the extension area, and the extension area is milled off before the temporary support plate is removed.

[0011] Furthermore, the alignment targets are in two groups, each group including multiple target patterns, and the distance between adjacent target patterns in the same group is ≥3.0mm; During the alignment process of drilling laser holes in the multi-layer structure using the alignment targets, the laser holes on the upper side of the temporary support plate are aligned using the first set of alignment targets, and the laser holes on the lower side of the temporary support plate are aligned using the second set of alignment targets.

[0012] Furthermore, when creating circuit patterns on the intermediate structure, the circuit patterns located above and below the temporary support plate are exposed using the same set of films, and are flipped horizontally at 180°.

[0013] Furthermore, before using the alignment target for alignment, the method further includes: Remove the additional conductive layer and additional dielectric layer covering the alignment target to expose the alignment target; the removal method is: to remove the additional conductive layer and additional dielectric layer simultaneously by laser ablation, or to first etch away the additional conductive layer by pattern transfer method and then remove the additional dielectric layer by laser ablation.

[0014] Furthermore, the method for removing the temporary support plate is as follows: Mill off the extended region; The temporary support plate can be peeled off directly, or the peelable adhesive layer can be softened by baking before peeling off the temporary support plate.

[0015] Furthermore, the first conductive layer is a conductive layer on the control surface side, and the additional conductive layer is a conductive layer on the LED bead surface.

[0016] Secondly, the present invention provides a high-density circuit board for mini LED lamp assembly, which is manufactured using the manufacturing method of the high-density circuit board for mini LED lamp assembly as described in any of the preceding claims.

[0017] The main beneficial effects of this technical solution are: The present invention discloses a method for manufacturing a high-density circuit board for mini LED light assemblies and the circuit board itself. By setting a temporary support plate and fixing the first conductive layer on its upper and lower surfaces with a peelable adhesive layer, the originally thin mini LED circuit board gains rigid support during processing, effectively avoiding mechanical damage such as creases, tears, stretching, or even penetration caused by the thinness of the board, thus significantly improving the processing yield. A double-sided synchronous lamination process is employed, simultaneously fabricating circuit patterns, blind vias, and laser vias on both the upper and lower sides of the temporary support plate. Two sub-boards can be produced simultaneously in a single lamination, significantly reducing equipment start-up and shutdown time and material changeover time, and improving mass production efficiency. By simultaneously forming alignment targets during the etching step of blind via fabrication, and using these alignment targets for precise alignment during subsequent laser drilling, the alignment accuracy in the high-density interconnect structure is guaranteed, meeting the stringent requirements of mini LED light assemblies for the accuracy of tiny pad positions. Simultaneously, the inclusion of anti-delamination structures (such as anti-explosion holes) effectively prevents delamination and slippage problems during multiple lamination processes, further improving processing stability and yield. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1This is a flowchart illustrating a method for manufacturing a high-density circuit board for a mini LED lamp assembly according to Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of a carrier structure formed by pasting copper foil on both the upper and lower sides of a carrier plate, as provided in Embodiment 2 of the present invention. Figure 3 A physical diagram of a carrier structure after bonding, provided for Embodiment 2 of the present invention; Figure 4 This is a schematic diagram of a completed circuit pattern core board structure provided in Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of a preferred target graphic design provided in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of a flipping method for fabricating surface circuit patterns on a circuit pattern core board according to Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of a completed outer layer laminate structure provided in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of a completed second laser hole provided in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of two sub-plates obtained after peeling off a carrier plate, according to Embodiment 2 of the present invention.

[0020] Figure 10 This is a schematic diagram showing the completed electroplating of a sub-board according to Embodiment 2 of the present invention; Figure 11 This is a schematic diagram of a sub-board after surface circuit pattern fabrication, provided in Embodiment 2 of the present invention; Figure 12 This is a schematic diagram of a sub-board with a solder resist image fabricated on its surface, as provided in Embodiment 2 of the present invention.

[0021] Explanation of reference numerals: 1. Carrier board structure; 2. First sub-board; 3. Second sub-board; 10. Carrier board; 20. First copper foil; 21. First cured sheet; 22. Third copper foil; 23. First blind via; 24. First set of target images; 25. Second set of target images; 26. Third prepreg; 27. Fifth copper foil; 28. Second laser hole; 29. ​​Second blind via; 210. Electroplated copper; 211. Solder mask image; 30. Second copper foil; 31. Second prepreg; 32. Fourth copper foil; 33. Fourth prepreg; 34. Sixth copper foil.

[0022] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0025] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0027] To better understand the above technical solution, a detailed explanation of the technical solution is provided below with reference to the accompanying drawings.

[0028] Example 1

[0029] Figure 1 This is a flowchart illustrating a method for manufacturing a high-density circuit board for a mini LED lamp assembly according to Embodiment 1 of the present invention. Figure 1 As shown, the method includes: Step S100: Provide a temporary support plate, and fix the first conductive layer to the upper and lower surfaces of the temporary support plate respectively by a peelable adhesive layer to form a support structure; Step S200: Drill alignment marks and anti-delamination structures on the support structure; Step S300: A dielectric layer and a second conductive layer are stacked sequentially above and below the support structure, and then pressed together to form an intermediate structure; Step S400: A blind hole is formed on the intermediate structure, and a positioning target is simultaneously etched during the etching step of forming the blind hole. Step S500: Create a circuit pattern on the intermediate structure; Step S600: At least one additional dielectric layer and at least one additional conductive layer are further stacked above and below the intermediate structure, and then pressed together to form a multilayer structure; Step S700: Alignment is performed using the alignment target, and laser holes are drilled in the multi-layer structure; Step S800: Remove the temporary support plate to obtain the first sub-plate and the second sub-plate; Step S900: Electroplating and subsequent processing are performed on the first and second sub-boards.

[0030] This invention aims to provide a method for manufacturing a high-density circuit board for mini LED light assemblies, thereby solving the problems of processing damage and low single-piece processing efficiency caused by excessively thin boards in existing technologies. Specific objectives include: Preventing processing damage: By introducing temporary support plates to increase the rigidity of the thin plates, creases, tears, stretching, or even penetration can be avoided during processes such as pressing, drilling, and handling.

[0031] Improve production efficiency: Enable double-sided synchronous lamination, produce two sub-boards at the same time in one pressing, and reduce auxiliary time by splicing boards.

[0032] Ensuring alignment accuracy: An alignment target is simultaneously formed during the blind hole fabrication process, providing a precise reference for subsequent laser drilling and meeting the stringent requirements of mini LED light assemblies for the accuracy of the position of tiny pads.

[0033] The following describes the implementation of the present invention in detail using the fabrication of a double-sided high-density circuit board for a mini LED light assembly (each sub-board ultimately has a three-layer conductive layer structure) as an example.

[0034] Prepare the materials, including: Temporary support board: Use FR-4 copper-clad laminate with a thickness of 1.0-1.5mm, or aluminum plate with a thickness of 1.2mm. The board surface should be flat and the warpage should be less than 0.5%. It is preferred to use 1.2mm copper-clad laminate after removing the copper foil as the carrier.

[0035] Peelable adhesive layer: High-temperature resistant silicone micro-adhesive tape (such as 3M 5413 polyimide tape), approximately 0.05mm thick, with a peel force of 0.1~0.3N / cm at room temperature, and can withstand high temperatures of 200°C.

[0036] Conductive layer: Select copper foil of a specific thickness according to actual needs, such as 18µm or 35µm.

[0037] Dielectric layer: Select FR-4 prepreg (such as type 1080 or type 2116) according to actual needs, with a resin content of 40%~50% and moderate fluidity.

[0038] Step S100: Form the support structure.

[0039] Micro-adhesive layers are attached to the upper and lower surfaces of a temporary support plate, respectively. Then, a first copper foil (e.g., 18µm) and a second copper foil are flatly pressed onto the micro-adhesive layers on the upper and lower surfaces, respectively, with the first copper foil on the upper side and the second copper foil on the lower side. Air bubbles are removed to form a support structure. These first and second copper foils will subsequently become the control surface circuitry of the sub-board's outer layer.

[0040] Step S200: Drill alignment marks and anti-delamination structure.

[0041] Alignment marks: Drill target holes on the tool edge of the support structure (the non-effective area reserved on the edge of the plate) to provide X-ray target holes for use after the subsequent pressing process. The diameter can be 1.0mm.

[0042] Anti-delamination structure: At a relatively tight distance from the edge of the board, drill a ring of explosion-proof holes or grooves around the edge, with a hole spacing of 1.0-3.0mm. The diameter of the explosion-proof holes is relatively small, generally 0.2mm to 1.0mm. After subsequent lamination, the prepreg is poured into the explosion-proof holes, and after curing, it forms "rivets," creating a temporary "integrated structure" for the carrier structure during processing. This prevents problems such as delamination, board bursting, and slippage of the carrier structure during processing, thus improving processing accuracy.

[0043] Step S300: First pressing to form the intermediate structure.

[0044] A dielectric layer and a second conductive layer are stacked sequentially above and below the support structure, such as the third copper foil, the first prepreg, the carrier layer, the second prepreg, and the fourth copper foil, stacked symmetrically. The material is then fed into a press, and the pressing parameters are selected according to the type of prepreg, such as maintaining a temperature of 180°C and a pressure of 300 psi for 90 minutes to cure the prepreg and bond the layers together to form the intermediate structure. At this point, the relative positions between the first and third copper foils, and between the third copper foil and the support plate, are fixed. Similarly, the relative positions between the second and fourth copper foils, and between the fourth copper foil and the support plate, are fixed.

[0045] Step S400: Create blind holes and simultaneously form alignment targets.

[0046] The specific process is as follows: Applying dry film: Applying dry film to the upper and lower surfaces of the intermediate structure.

[0047] Exposure: A film is used, which includes blind hole window patterns and alignment target patterns (e.g., cross-shaped, 0.2mm line width) at the four corners of the board edge. During exposure, alignment is performed based on the alignment marks drilled in step S200.

[0048] Development: Remove the dry film from the unexposed areas to expose the copper foil areas that need to be etched (such as blind hole locations and target locations).

[0049] Etching: The exposed copper foil is etched away using an acidic etching solution (such as copper chloride). This step simultaneously removes the copper foil at the blind via locations and the target locations, exposing the surface of the underlying prepreg. The dry film is then removed after etching.

[0050] Laser drilling: Using the etched alignment target as a reference, a CO2 or UV laser is used to drill a hole at the blind hole opening position, penetrating the prepreg until it reaches the first copper foil below (or the copper foil on the support structure), forming a blind hole.

[0051] Electroplating for via filling: Full-board electroplating (via filling electroplating) fills blind vias with copper electroplating to achieve interlayer electrical interconnection.

[0052] At least one set of alignment targets should be made (e.g., one at each of the four corners) for subsequent laser drilling alignment. Multiple sets of targets can be made if higher precision is required.

[0053] Step S500: Create the circuit diagram.

[0054] Circuit patterns are fabricated on the upper and lower surfaces of the intermediate structure. The process is as follows: dry film application → exposure based on the alignment marks from step two (the film contains the desired circuit patterns) → development → etching → film removal. This forms the third circuit pattern (upper surface) and the fourth circuit pattern (lower surface). These circuit patterns are generally inner layer signal lines or power / ground planes used for electrical interconnection.

[0055] Step S600: Second pressing to form a multi-layer structure.

[0056] Stack the following layers sequentially on top of the intermediate structure: the third prepreg and the fifth copper foil; stack the following layers sequentially on bottom of the intermediate structure: the fourth prepreg and the sixth copper foil. Then, stack and arrange these layers in the following order: the fifth copper foil, the third prepreg, the circuit pattern core board (intermediate structure), the fourth prepreg, and the sixth copper foil. Finally, press them together again (pressing parameters are selected according to the type of prepreg, such as temperature 180°C, pressure 300psi, and time 90 minutes) to form the outer laminate. At this point, the fifth and sixth copper foils will become the outermost layers (LED bead surfaces) of the two sub-boards, respectively.

[0057] Step S700: Drill laser holes using a positioning target.

[0058] First, use X-ray to probe the target hole drilled in step S200 (which has been pressed into the plate), and then drill a mechanical alignment target hole (generally 3.0 mm in diameter) at the corresponding position.

[0059] Then, using the alignment target etched in step S400 as a reference, a second laser hole is drilled on the fourth and fifth copper foils using a laser drilling device. These laser holes penetrate the outer copper foil and the prepreg, down to the inner circuit pattern (the upper side is the third circuit pattern, and the lower side is the fourth circuit pattern), forming a stacked hole structure.

[0060] Since the target may be covered by the outer copper foil and prepreg, the covering layer needs to be removed first using laser ablation or pattern transfer methods to expose the target. Specifically, this can be done by first etching away the outer copper foil at the target location, and then using a laser to ablate the prepreg.

[0061] Step S800: Remove the temporary support plate.

[0062] First, mill away the area corresponding to the anti-delamination structure along the edge of the tool. Then, flow the prepreg into the anti-delamination structure and let it cure to form "rivets" which are then removed, exposing the edge of the support plate.

[0063] Then, use suction cups or similar tools to peel the two sub-boards off the micro-adhesive layer from the edges of the temporary support plate. If the adhesive is strong, the layer can be softened by baking at 80°C~100°C before peeling. After peeling, the first and second sub-boards are obtained, each containing three layers of copper foil (first, third, and fifth / second, fourth, and sixth) and two layers of dielectric.

[0064] Step S900: Electroplating and subsequent processes.

[0065] Generally, the entire board is electroplated. Two sub-boards are placed into the electroplating line respectively, and a thin layer of copper (about 5~10µm) is plated on the surface to increase the copper thickness and protect the hole wall. The laser hole made in step S700 is then filled to form a blind hole.

[0066] Post-processing: Fabrication of surface circuit patterns and solder mask patterns (such as ink), surface treatment (such as immersion gold or OSP), shaping (CNC milling of the final shape), electrical testing, etc. This process is the same as the existing manufacturing method, but adjustments will be made according to actual needs, and will not be elaborated further.

[0067] The final product consists of two independent high-density circuit boards for mini LED lamp groups. Each board has three conductive layers (control surface + intermediate signal layer + LED lamp bead surface), and blind vias and laser vias enable interlayer interconnection, which can be used to mount mini LED lamp beads.

[0068] The embodiments of this invention can prevent processing damage through the above processing steps: after the temporary support plate is combined with the thin copper foil, the overall thickness increases, significantly improving the bending strength. No creases, tears, or penetrations occur during pressing, handling, and drilling, increasing the processing yield from approximately 70% in traditional processes to over 98%. It also improves production efficiency: double-sided synchronous lamination allows for the simultaneous production of two sub-boards in one pressing operation, doubling the output per unit time, reducing equipment start-up and shutdown time and material changeover time, and significantly improving overall efficiency. The alignment target formed synchronously in the blind via etching step is manufactured in the same process as the blind via pattern, ensuring high relative positional accuracy (error ≤ ±0.01mm). Subsequent laser drilling uses this target for alignment, achieving a hole position accuracy of ±0.025mm, meeting the process requirements of mini LED pads (typical size 0.1~0.3mm).

[0069] Furthermore, the temporary support plate is an insulating carrier plate or a metal carrier plate; the peelable adhesive layer is a micro adhesive layer or a heat-peelable adhesive layer.

[0070] The commonly used material for the insulating carrier board is FR-4 glass fiber reinforced epoxy resin copper-clad laminate (the substrate after copper foil removal can also be used), with a thickness of 0.8~1.6mm. High Tg (glass transition temperature) FR-4, polyimide (PI) boards, or BT resin boards can also be used to accommodate higher temperature lamination processes. The board surface must be flat, with a warpage ≤0.5%, to avoid copper foil wrinkling or uneven lamination due to unevenness of the carrier board. Before bonding with the micro-adhesive layer, the surface must be cleaned (plasma treatment or chemical cleaning) to improve adhesive adhesion.

[0071] The commonly used materials for metal carrier plates are aluminum plates (5052, 6061) or stainless steel plates (304), with a thickness of 0.5~1.0mm. The surface of the aluminum plate can be anodized or coated to improve corrosion resistance and adhesive adhesion.

[0072] The micro-adhesive layer material can be high-temperature resistant silicone pressure-sensitive tape (such as 3M 5413, Nitto 5302A), with a thickness of 0.05~0.1mm and a peel strength of 0.1~0.5N / cm. Coated silicone (liquid silicone spin-coated or screen-printed and then cured) can also be used, but the thickness uniformity must be controlled. Apply the micro-adhesive tape smoothly to the carrier board surface using a laminator or roller, avoiding air bubbles. If using a coated type, form a uniform thin layer by spin-coating or spraying, followed by heat curing. The micro-adhesive layer maintains its tackiness at a pressing temperature of 170~200°C, without softening or flowing, and without releasing gas. After pressing, peel off the carrier board manually or mechanically from the corners. Due to its low tack, it can be peeled off directly, leaving no adhesive residue on the copper foil surface. If a small amount remains, wipe it with alcohol or a special cleaning agent.

[0073] For heat-release adhesive layers, high-temperature triggered heat-release tapes (such as Nitto Denko REVALPHA series and 3M 9667LE) can be selected, with a typical release trigger temperature of 180~200°C. Thermal foam adhesives can also be used (which generate bubbles upon heating to a set temperature, causing a sharp decrease in tack). The pressing temperature must be lower than the trigger temperature of the heat-release adhesive (e.g., pressing temperature 170°C, trigger temperature 190°C) to ensure the adhesive layer remains tacky during pressing and does not peel off prematurely.

[0074] Furthermore, the anti-delamination structure consists of explosion-proof holes distributed around the edge of the plate, the diameter of the explosion-proof holes being 0.2mm to 1.0mm, and the distance between the explosion-proof holes and the edge of the plate being 1.0mm to 5.0mm.

[0075] Explosion-proof holes (also known as anti-delamination holes or rivet holes) are small-diameter through holes drilled around the edge of the substrate in the tool area of ​​the carrier structure. During lamination, the prepreg melts under heat, and the resin flows into the explosion-proof holes. After curing, it forms resin "rivets" that mechanically interlock the layers of the carrier plate, copper foil, and prepreg, preventing delamination and slippage under subsequent machining (such as drilling or milling) or thermal stress.

[0076] The aperture should be selected from 0.2mm to 1.0mm, preferably 0.3mm to 0.5mm. Too small an aperture will hinder resin flow; too large an aperture will weaken the board edge strength and may cause excessive resin overflow. The hole spacing is generally 1.0mm to 3.0mm to ensure a continuous "rivet" chain without excessively weakening the carrier structure. The distance from the board edge should be 1.0mm to 5.0mm, preferably 2.0mm to 3.0mm. Too close a distance can easily cause the board edge to break; too far a distance results in a longer resin flow path, reduced effectiveness, and requires more tooling space. The explosion-proof holes should not overlap with target holes, milling positioning holes, etc.

[0077] Furthermore, the method also includes: The panel dimensions are extended outward to form an extension area, the anti-delamination structure is set in the extension area, and the extension area is milled off before the temporary support plate is removed.

[0078] The extension area refers to a new area formed by extending the original designed panel outwards (on one side or all four sides) by a certain width (usually 3~10mm). This area is not part of the effective area of ​​the final finished circuit board and is only used to support auxiliary tool structures (such as explosion-proof holes, alignment marks, etc.) or improve the processing technology.

[0079] The anti-delamination structure (explosion-proof holes) is placed within the extension area, rather than occupying the tool area or effective area. After all pressing, drilling, and wiring are completed, the extension area is first cut off using a CNC milling machine, and then the temporary support plate is removed. The explosion-proof holes are removed simultaneously with the extension area, preventing interference or residue in subsequent processes.

[0080] The extension area is preferably 5mm to 8mm, and needs to accommodate the explosion-proof hole (1 to 5mm from the edge of the board) and the milling cutter path. Extending around the perimeter ensures uniform stress distribution at the board edge and provides the best anti-delamination effect. During removal, milling is performed along the boundary line between the tool area and the extension area (i.e., the original panel outline), circumferentially cutting away the entire extension area. After milling, the edge of the carrier board is exposed (because the extension area has been removed, the tool area and effective unit area are retained).

[0081] Setting up an extension area can avoid interference between the explosion-proof hole and the tool area structure, and prevent the explosion-proof hole residue from affecting the finished board.

[0082] Furthermore, the alignment targets are in two groups, each group including multiple target patterns, and the distance between adjacent target patterns in the same group is ≥3.0mm; During the alignment process of drilling laser holes in the multi-layer structure using the alignment targets, the laser holes on the upper side of the temporary support plate are aligned using the first set of alignment targets, and the laser holes on the lower side of the temporary support plate are aligned using the second set of alignment targets.

[0083] There are two sets of blind hole alignment target patterns.

[0084] The first set of alignment targets consists of multiple (usually 4) independent target shapes (such as cross, circle, concentric circles, etc.) distributed at different positions on the edge of the board (such as the four corners).

[0085] The second set of aligned targets also consists of multiple target patterns, which are offset from the first set in position (for example, the first set is at the four corners, and the second set is at the midpoint of the four sides; or the first set is in the left half of the area, and the second set is in the right half of the area), and the distance between the two sets of target patterns is relatively large (the distance between adjacent target patterns is ≥3.0mm).

[0086] By designing two sets of targets, and using a different set for the upper and lower surfaces respectively, it is possible to detect the overall displacement of the upper and lower inner layers in the same direction and with the same amount.

[0087] When only one set of blind hole alignment target patterns is created, a relative offset may occur between the third and fourth circuit patterns after the second lamination. If this offset is in the same direction and by the same amount (e.g., both the upper and lower layers offset to the left by the same distance simultaneously), then when drilling the second laser hole using the same set of film or the same set of alignment data, the laser holes on both the upper and lower surfaces will be offset in the same direction following their respective targets. Since the relative positions between the upper and lower targets do not change, this offset cannot be detected, causing the final hole position to deviate from the design position, increasing the probability of error.

[0088] Using two sets of blind hole alignment target patterns allows for mutual reference. Specifically, when drilling the second laser hole, the first set of alignment targets is used for alignment on the upper side (the fifth copper foil side), and the second set is used on the lower side (the sixth copper foil side). Because the two sets of targets are positioned differently in the horizontal direction, when the upper and lower inner layers shift in the same direction and amount, the intersection distance between the first set of targets on the upper side and the second set on the lower side will change, thus detecting the shift. This reduces the probability of misjudging interlayer misalignment after the second lamination (i.e., the relative shift between the third and fourth circuit patterns) and prevents systematic misalignment of the laser holes on both sides.

[0089] Mutual verification: By measuring the actual distance between the first set of targets and the second set of targets (e.g., the distance between the first set of targets in the upper left corner and the second set of targets on the same side) and comparing it with the design value, the relative offset between the upper and lower inner layers can be quantified. If the offset exceeds the tolerance, the process can be adjusted in time or the product can be scrapped to avoid defective products.

[0090] Furthermore, by designing two sets of targets, it is possible to prevent the blind hole alignment target pattern of one set from being damaged during subsequent pressing, such as incompleteness or skewness, making the target unusable. In this case, the other set can be used as a backup.

[0091] The target pattern and the blind hole pattern are formed in the same process and under the same film. The first set of targets is located near the four corners of the plate edge, 5mm away from the plate edge in the X direction and 5mm away in the Y direction. The second set of targets is located at the midpoint of each edge or near the four corners but offset by a certain distance (e.g., 15mm away from the plate edge in the X direction and 15mm away in the Y direction), or at the four different corners of the tool area.

[0092] After the second lamination, the target pattern may be covered by additional conductive layers (fifth and sixth copper foils) and additional dielectric layers (third and fourth prepregs). These coverings need to be removed first. The board is then fed into a laser drilling machine. The equipment first identifies the first set of targets (e.g., using a CCD camera to find four crosshairs), calculates the expansion and contraction and offset, and then drills the second laser hole on the upper surface (fifth copper foil side) based on this. Then, the board is flipped (or a dual-table device works simultaneously), the second set of targets is identified, and the second laser hole is drilled on the lower surface (sixth copper foil side).

[0093] Furthermore, when creating circuit patterns on the intermediate structure, the circuit patterns located above and below the temporary support plate are exposed using the same set of films, and are flipped horizontally at 180°.

[0094] Typically, the circuit patterns on the upper and lower surfaces of the intermediate structure are mirror-symmetrical (for example, the pad positions on the upper surface and the lower surface are designed to correspond one-to-one). Therefore, the same set of films can be used for exposure, and the patterns on the same set of films are fixed, with identical patterns used on the upper and lower surfaces, ensuring complete consistency in the theoretical design. This avoids the expansion and contraction differences caused by different films due to manufacturing processes, storage environments, etc. Moreover, only one film design is required, eliminating the need to create separate films for the upper and lower surfaces. A 180° horizontal rotation maintains the orientation of the patterns, only causing a centrally symmetrical translation. This allows for precise alignment of the patterns on the upper and lower surfaces.

[0095] Using the same set of films and a 180° horizontal flip ensures a high degree of consistency in the circuit patterns on the upper and lower surfaces, eliminating film-to-film errors and mirroring mistakes, and providing a precise inner-layer reference for subsequent laser drilling.

[0096] Furthermore, before using the alignment target for alignment, the method further includes: Remove the additional conductive layer and additional dielectric layer covering the alignment target to expose the alignment target; the removal method is: to remove the additional conductive layer and additional dielectric layer simultaneously by laser ablation, or to first etch away the additional conductive layer by pattern transfer method and then remove the additional dielectric layer by laser ablation.

[0097] The alignment target is a pattern (such as a cross) on a copper foil, whose surface was originally bare copper. However, after the second lamination, a prepreg and then copper foil are successively covered on top of the target, both of which obstruct optical recognition. Therefore, the cover layer must be removed to expose the target so that it can be captured by the CCD camera.

[0098] Laser ablation can be used to simultaneously remove both the additional conductive and dielectric layers. The approximate location of the target is determined using pre-stored target design coordinates (or pre-positioning via X-ray). The laser beam scans and ablates along a predetermined path (e.g., a box slightly larger than the target image). For example, using a UV laser, preferred parameters are: wavelength: 355 nm, pulse energy: 10~50 µJ, scanning speed: 500~2000 mm / s, number of scans: 3~10 (adjusted according to thickness). The laser energy needs precise control to remove the overlay layer just enough to avoid damaging the target copper foil.

[0099] Alternatively, the additional conductive layer can be etched away first using pattern transfer, and then the additional dielectric layer can be removed by laser ablation. By using a step-by-step method (etching copper first, and then ablation the prepreg with a low-energy laser), the integrity of the target can be protected to the greatest extent.

[0100] Both groups ensured reliable exposure of the target.

[0101] Furthermore, the method for removing the temporary support plate is as follows: Mill off the extended region; The temporary support plate can be peeled off directly, or the peelable adhesive layer can be softened by baking before peeling off the temporary support plate.

[0102] The extension zone is an additional area extending from the perimeter of the panel, and the anti-delamination structure (explosion-proof holes) is located within this extension zone. Before removing the temporary support plate, the extension zone must be milled off for the following reasons: Exposing the carrier plate edge: The extension zone covers the edge of the temporary support plate. If not removed first, the edge of the temporary support plate is encased by the extension zone material (copper foil, prepreg, explosion-proof holes, etc.), preventing direct contact with the carrier plate itself. Milling off the extension zone exposes the edge of the carrier plate (i.e., the original panel boundary), facilitating subsequent peeling. Removing the explosion-proof holes: The explosion-proof holes are filled with cured resin. If retained, they will generate additional anchoring force during peeling, increasing the difficulty of peeling and potentially tearing the copper foil. Milling off the extension zone removes the explosion-proof holes, eliminating the fixing effect of these "rivets." Avoiding stress concentration: When peeling off the temporary support plate, if the edges are uneven or have protrusions (such as residual explosion-proof holes), stress will concentrate in these areas, leading to copper foil tearing or carrier plate breakage. Milling off the extension zone results in smooth edges and uniform peeling force.

[0103] The peelable adhesive layer is a micro-adhesive layer, and its tackiness remains at a low level after lamination, allowing for direct peeling. After peeling, check the surface of the daughterboard (the original first or second copper foil) for any adhesive residue. If any is found, wipe it with alcohol or a special cleaning agent.

[0104] The peelable adhesive layer is either a heat-release adhesive layer or a micro-adhesive layer with high tack at low temperatures, which softens and reduces tack after baking. For heat-release adhesives: heating above the trigger temperature causes the adhesive layer to foam or soften, resulting in a sharp decrease in tack. For micro-adhesive layers: heating to 80~120°C softens the adhesive layer and reduces tack, allowing for better peeling.

[0105] By first milling off the extension area and then peeling off the temporary support plate, the two sub-boards are ensured to be completely independent with neat edges and no adhesion. Moreover, the standardized peeling operation reduces defects such as copper foil wrinkling, tearing, and carrier board residue caused by improper peeling.

[0106] Furthermore, the first conductive layer is a conductive layer on the control surface side, and the additional conductive layer is a conductive layer on the LED bead surface.

[0107] After removing the temporary support plate, the two outer surfaces of the first sub-board are: the first copper foil (originally attached to the lower surface of the carrier board) – exposed, becoming the control surface; and the fifth copper foil (the outermost laminated copper foil) – exposed, becoming the LED bead surface. The first conductive layer was attached to the carrier board in step one, and after multiple laminations and high-temperature treatments, its surface may have undergone slight oxidation or contamination. However, its final exposure occurs after the carrier board is removed, at which point all high-temperature processes are completed, so the surface quality requirements for the control surface are relatively low and acceptable. The additional conductive layers (the fifth and sixth copper foils) are added during the final lamination, and subsequently only undergo laser drilling, electroplating, and outer layer circuit fabrication processes, without experiencing multiple high-temperature and high-pressure processes. Therefore, their surface quality is higher and they are more suitable for making fine solder pads.

[0108] This embodiment effectively solves the processing damage problems of high-density circuit boards for miniLED lamp groups, which are prone to creases, tears, stretching, and even penetration due to their thinness, by introducing a temporary support plate and simultaneously laminating it on both its upper and lower surfaces. It also nearly doubles the processing efficiency per piece. By setting explosion-proof holes on the carrier structure and forming resin rivets after lamination, delamination and slippage during multiple lamination processes are significantly suppressed, ensuring interlayer stability. Alignment targets are simultaneously formed during the blind hole etching step, providing a precise reference for subsequent laser drilling. Furthermore, the operation of milling off the extension area before peeling off the carrier plate avoids interference from the explosion-proof holes during peeling, and allows for direct peeling or baking and softening peeling based on the adhesive layer characteristics, ensuring no damage or residue on the sub-board surface. Finally, the functional division of the first conductive layer as the control surface and the additional conductive layer as the LED bead surface allows for optimization of copper foil thickness and surface treatment for different needs, thereby improving driving capability and heat dissipation performance while ensuring a high yield of LED bead soldering. In summary, the embodiments of the present invention achieve high-quality, high-efficiency, and high-reliability manufacturing of high-density circuit boards for mini LED lamp groups.

[0109] Example 2

[0110] Embodiment 2 of the present invention provides a method for manufacturing a high-density circuit board for mini LED lamp groups, including the following steps.

[0111] 1. Create the carrier structure.

[0112] Please see Figure 2 , Figure 2 This is a schematic diagram of the carrier structure (i.e., the support structure in Example 1) formed after copper foil is pasted on both the top and bottom sides of the carrier plate.

[0113] The specific process is as follows: take the carrier plate 10, and take the first copper foil 20 and the second copper foil 30, and attach a micro-adhesive layer to the surface of the carrier plate 10. Figure 2(Not shown in the image) The first copper foil 20 and the second copper foil 30 are respectively pressed onto the upper and lower surfaces of the carrier plate 10 to form a carrier structure. The actual image of the bonded structure is shown in the image. Figure 3 As shown.

[0114] Drill holes in the tool area 80 outside the forming line 50 of the carrier structure, including target holes 70 (function: to provide X-ray target holes for use after subsequent pressing processes).

[0115] Optionally, the drilling also includes explosion-proof holes 60. Explosion-proof holes 60 are holes drilled around the tool area along the edge of the board (as close to the edge as possible; if there is an extension area, then the extended edge of the board). Optionally, the distance from the edge is 1.0mm to 5.0mm, preferably 2.0mm or 3.0mm. The diameter of the explosion-proof holes 60 is relatively small, generally 0.2mm to 1.0mm. The function of the explosion-proof holes 60 is: after subsequent lamination, the prepreg flows into the explosion-proof holes, forming a temporary "integrated structure" for the carrier structure during processing. This prevents problems such as delamination, board bursting, and slippage of the carrier structure during processing, thus improving processing accuracy.

[0116] Optionally, the panel dimensions in the original design data can be extended outwards on one side (e.g., by 5.0mm or 8.0mm). This creates an extension area 90 outside the original tool area 80, forming a new extension edge outside the panel edge 40. The tool area 80 contains the tool graphics required for processing (e.g., the target hole 70 above), while the extension area 90 contains the tool graphics or tool structures to be milled off in subsequent processing (rather than being milled off in the final forming). For example, the explosion-proof hole 60 above is located in the extension area 90. When the carrier plate needs to be removed later, the extension area 90 is milled off first (without milling off the tool area 80) to separate the panels before proceeding with subsequent processing.

[0117] The first copper foil 20 and the second copper foil 30 are used to form the circuit pattern on the control side, not the LED bead side; the circuit pattern on the LED bead side is formed by the subsequent fifth and sixth copper foils. The main reason for this arrangement is that after all the lamination and drilling processes are completed, the temporary support plate (carrier plate) needs to be peeled off from the sub-board. During the peeling process, the first and second copper foils, which are directly attached to the carrier plate, will be subjected to large mechanical stresses (such as bending, stretching, and peeling forces), which can easily cause slight deformation or positional displacement. The circuits on the control side are usually wider (e.g., line width / spacing ≥ 0.1 mm), and have a higher tolerance for pattern positional accuracy; even if a slight deviation occurs, it will not affect the electrical performance. Conversely, the pads on the LED bead side are extremely small and fine (e.g., diameter 0.1~0.3 mm, spacing 0.3~0.5 mm), and have extremely high requirements for pattern positional accuracy (usually within ±0.02 mm). If the LED bead surface is placed on the first or second copper foil, the stress during peeling from the carrier board will be directly transferred to these delicate pads, easily causing pad deformation, misalignment, or even detachment, resulting in product scrap. Therefore, by placing the LED bead surface on the fifth and sixth copper foils, which are far from the carrier board, these copper foils do not directly bear the peeling stress during peeling, thus protecting the integrity and positional accuracy of the delicate pads. Simultaneously, with the control surface placed on the first and second copper foils, even slight deformation during peeling will not affect the functional reliability of the final product. This functional division effectively reduces process risks and improves yield.

[0118] 2. Fabricate the circuit pattern core board.

[0119] The completed circuit pattern core board structure is as follows: Figure 4 As shown, the manufacturing process is as follows: Take the first semi-cured sheet 21, the third copper foil 22, the second semi-cured sheet 31, and the fourth copper foil 32, and stack and press them in sequence according to the order of taking the third copper foil 22, the first semi-cured sheet 21, the carrier structure 1, the second semi-cured sheet 31, and the fourth copper foil 32. Then, use X-ray to examine the target holes (pressed into the board body) to make alignment target holes.

[0120] Next, blind vias are made, and then surface circuit patterns are made to form a circuit pattern core board (the third copper foil 22 is processed into the third circuit pattern; the fourth copper foil 32 is processed into the fourth circuit pattern).

[0121] The basic process for making a blind hole is as follows: Apply dry film → Alignment (align with the alignment target hole), exposure, development, etching (etch away the copper at the blind hole position (including forming the blind hole alignment target pattern. See below for details)), film removal → (align with the laser alignment target, then) laser drilling → whole board electroplating (hole filling electroplating) to obtain the first blind hole 23.

[0122] The basic process for creating surface circuit patterns is as follows: Apply dry film → Alignment (align with the alignment target holes), Exposure, Development, Etching, Film Removal.

[0123] During the above-mentioned blind via fabrication process, blind via alignment target patterns (located at the four corners of the board edge) need to be etched simultaneously during etching. That is, the third and fourth circuit patterns contain blind via alignment target patterns (their function is to provide alignment targets for laser drilling). The alignment target is especially important when the copper foil is thin and laser drilling uses "copper drilling + substrate drilling" to directly drill copper to form blind vias.

[0124] Optionally, the blind hole alignment target patterns are divided into two groups, with each group consisting of four target patterns. The target patterns in the two groups are positioned far apart (optionally, the distance between adjacent target patterns is ≥3.0 mm). A preferred target pattern design is as follows: Figure 5 As shown, it includes a first set of target images 24 and a second set of target images 25.

[0125] In this embodiment, two sets of blind hole alignment target patterns were fabricated on the third and fourth circuit patterns, respectively. This design serves two main purposes.

[0126] The first function is redundancy and backup.

[0127] During the subsequent lamination process, one set of target patterns may become incomplete, skewed, or contaminated due to extrusion, resin flow, or other reasons, rendering it unusable. In this case, another set of target patterns can be used as a backup to ensure that the alignment process can still proceed smoothly and to avoid the entire board being scrapped due to the failure of a single set of targets.

[0128] The second function is to detect and prevent interlayer misalignment.

[0129] After the second lamination (i.e., laminating the third prepreg, the fifth copper foil, the fourth prepreg, and the sixth copper foil), the second laser hole needs to be fabricated. The specific process is as follows: after lamination, the burrs are first milled off, the target hole is probed with X-ray and milled positioning holes are drilled, and then, using the milled positioning holes as a reference, the outer copper foil and prepreg covering the blind hole target pattern position are removed using laser ablation or pattern transfer methods to expose the inner blind hole alignment target pattern. Finally, using these target patterns as a reference, precise alignment is performed, and laser drilling is performed to form the second laser hole.

[0130] If only one set of blind hole alignment target patterns is created, then the fifth and sixth copper foils typically use the same set of films (i.e., the same set of alignment data) when creating the second laser hole. In this case, if a relative misalignment occurs between the third and fourth circuit patterns after the second lamination (e.g., the upper and lower layers simultaneously shift by the same distance in the same direction), the laser holes on both the upper and lower surfaces will follow their respective targets and be misaligned in the same direction. Since the relative positions between the upper and lower targets do not change, this misalignment cannot be detected, causing the final hole position to deviate from the design position, increasing the probability of error.

[0131] By using two sets of blind hole alignment target patterns, mutual reference can be established. Specifically, when creating the second laser hole on the fifth copper foil (upper side), the first set of target patterns is used for alignment; when creating the second laser hole on the sixth copper foil (lower side), the second set of target patterns is used for alignment. Because the two sets of targets are positioned differently in the horizontal direction, when the upper and lower inner layers shift in the same direction and amount, the intersection distance between the upper first set of targets and the lower second set of targets will change, thus detecting the shift. This effectively reduces the probability of misjudging interlayer misalignment after the second lamination (i.e., the relative shift between the third and fourth circuit patterns), preventing systematic misalignment when creating the second laser hole on both sides.

[0132] It should be noted that in this embodiment, the first and second sets of targets are fabricated simultaneously on the third and fourth circuit patterns, rather than the first set only on the third circuit pattern and the second set only on the fourth circuit pattern. This is because if the latter were used, two different sets of films would need to be fabricated for the third and fourth copper foils, increasing cost and process complexity. By fabricating both sets of targets simultaneously on the circuit patterns on the upper and lower surfaces, only one set of films needs to be used to complete the exposure, simplifying the process and achieving the aforementioned redundancy and offset detection functions.

[0133] The two sets of target images are far apart to prevent them from being too close, which would cause the expansion and contraction to be more similar, and the deviation to be more similar, making it still difficult to determine whether there is a deviation.

[0134] When creating surface circuit patterns, the exposure method can be selected.

[0135] 1) Using the same set of film, that is, the third and fourth circuit patterns formed by the third and fourth copper foils are the same, can ensure that the expansion and contraction, alignment accuracy and position accuracy of the circuit patterns on both sides are more matched, providing the basic conditions for the subsequent production of other layers.

[0136] 2) When flipping, flip horizontally 180° without turning vertically. The flipping method is as follows: Figure 6 As shown.

[0137] 3. Fabricate the outer laminate.

[0138] The completed outer laminate structure is as follows: Figure 7 As shown, the specific process is as follows: Take the third prepreg 26, the fifth copper foil 27, the fourth prepreg 33, and the sixth copper foil 34; stack, arrange, and press them in the order of the fifth copper foil 27, the fourth prepreg 26, the circuit pattern core board (including the third copper foil 22, the first prepreg 21, the carrier structure (including the first copper foil 20, the carrier board 10, the second copper foil 30), the second prepreg 31, the fourth copper foil 32), the fifth prepreg 33, and the sixth copper foil 34 to form the outer laminate.

[0139] The process for creating the second laser hole is as follows: After lamination, X-ray detection and control are used first, then milling positioning holes are drilled, followed by milling off the burrs. Then, using the milled positioning holes as a reference, the fifth copper foil, third prepreg, sixth copper foil, and fourth prepreg at this location of the blind hole target pattern are burned off with a laser (or the copper foil on the blind hole target pattern is etched off using a pattern transfer process, and then the substrate is removed with a laser), exposing the blind hole alignment target pattern. The blind hole alignment target pattern is then precisely aligned, and laser drilling is performed to create the second laser hole. Figure 8 As shown, the second laser hole 28 is created.

[0140] 4. Sub-plate processing completed.

[0141] After completing the second laser hole, do not proceed with electroplating. At this point, the carrier structure must be removed because the first and second copper foils have not yet been electroplated, and the entire board needs to be electroplated (generally, copper plating is done on the copper foil of the copper-clad laminate). Therefore, the carrier board must be removed first.

[0142] To remove the carrier board, first mill off the extended area, then peel the sub-board off the carrier board. Since the carrier board is attached to the copper foil with micro-adhesive, it can be peeled off directly; alternatively, the micro-adhesive can be baked and softened before peeling off the carrier board. This results in two sub-boards, as shown below. Figure 9 As shown, the first sub-board 2 and the second sub-board 3 are obtained.

[0143] Afterwards, the first sub-board 2 and the second sub-board 3 that were removed were taken to be electroplated as a whole board.

[0144] Both sub-boards are electroplated as a whole, such as Figure 10 As shown, the second laser hole forms a second blind hole 29, and electroplated copper 210 is formed on the surface of the outer copper foil.

[0145] Then, surface circuit patterns are created separately, such as... Figure 11 As shown, the outer layer image of the completed sub-board is displayed.

[0146] Then, post-processing steps are performed (which may include: creating solder mask patterns, surface treatment, and shaping). The result is as follows: Figure 12 The molded plate shown has a solder resist image 211 on its surface.

[0147] This invention provides rigid support for the otherwise thin mini LED circuit board throughout the manufacturing process by setting up a temporary support plate and fixing the first conductive layer on its upper and lower surfaces with a peelable adhesive layer. This effectively avoids mechanical damage such as creases, tears, stretching, and even penetration caused by the thinness of the board, significantly improving the processing yield. A double-sided synchronous lamination process is employed, simultaneously fabricating circuit patterns, blind vias, and laser holes on both the upper and lower sides of the temporary support plate. Two sub-boards can be produced simultaneously in a single lamination. Combined with the panel expansion and extension area design, this reduces equipment start-up and shutdown time and material changeover time, nearly doubling production efficiency compared to single-piece processing. Explosion-proof holes are provided on the carrier structure and filled with semi-cured resin during lamination to form temporary "rivets," effectively preventing delamination and slippage during multiple lamination processes and ensuring interlayer stability. The explosion-proof holes are placed within the extension area and pre-milled before removing the carrier plate, avoiding interference with subsequent processes. During the etching step of creating blind vias, alignment targets are simultaneously formed, ensuring extremely high relative positional accuracy between the targets and the blind via pattern, providing a precise reference for subsequent laser drilling. The first conductive layer is used for the control surface, and an additional conductive layer is used for the LED bead surface. High-precision pads are placed on the fifth and sixth copper foils, far from the carrier board, avoiding the impact of mechanical stress during carrier board peeling on the pads. The control surface has wider lines and higher tolerance, able to withstand minor deformations that may occur during peeling. This functional division ensures high precision on the LED bead surface while reducing overall process risk. This embodiment systematically solves the problems in the prior art from multiple dimensions, including processing protection, production efficiency, interlayer alignment, anti-delamination, peeling reliability, and functional optimization, achieving high-quality, high-efficiency, and high-yield manufacturing of high-density circuit boards for mini LED light groups.

[0148] Example 3

[0149] Embodiment 3 of the present invention also provides a high-density circuit board for mini LED lamp groups, which is manufactured using the manufacturing method of the high-density circuit board for mini LED lamp groups as described in any of the preceding embodiments.

[0150] The high-density circuit board for mini LED lamp assembly in this embodiment of the invention is manufactured by the method for manufacturing high-density circuit board for mini LED lamp assembly in method embodiment one or two, so the description is relatively simple. For details, please refer to the relevant descriptions in the previous method embodiments, which will not be repeated here.

[0151] It is worth noting that the processing technology of this embodiment does not involve the processing technology of the positive and negative electrode pads for mini LED mounting. Therefore, the positive and negative electrode pads are not distinguished or marked in the accompanying drawings, which will not cause doubts or misleading those skilled in the art about "insufficient disclosure" or "unclear".

[0152] It should be noted that, due to the high precision of circuit board processing, the high density of circuit distribution, and the thinness of the stacked structure, all reaching the micron level, such as the thickness of the cover film being 25μm to 75μm, and the line width being 25μm, 50μm, etc., if the actual stacked structure is drawn, some layers or some patterns are difficult to represent; therefore, the accompanying drawings in this embodiment are graphic concepts that highlight the technical features, and do not represent the actual circuit board structure in the processing process, nor do they represent a scaled-up enlarged view of the processing structure.

[0153] This embodiment adopts a description method based on technical features as key nodes, and the existing technology in the processing process may not be described in detail. For example, the existing technology for circuit pattern making generally assumes "dry film application → exposure → development → etching → film removal", and the basic process of lamination generally assumes "core board layer extraction → prepreg extraction → stacking → fusion / riveting → layout → lamination → X-ray targeting → burr removal". Therefore, the understanding of this embodiment is mainly the understanding of the process of forming technical features during processing.

[0154] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made under the inventive concept of the present invention using the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing a high-density circuit board for a mini LED light assembly, characterized in that, Includes the following steps: A temporary support plate is provided, and a first conductive layer is fixed to the upper and lower surfaces of the temporary support plate by a peelable adhesive layer to form a support structure; Alignment marks and anti-delamination structures are drilled into the support structure; A dielectric layer and a second conductive layer are stacked sequentially above and below the support structure and then pressed together to form an intermediate structure. Blind holes are fabricated on the intermediate structure, and alignment targets are simultaneously etched during the etching step of fabricating the blind holes. Create circuit patterns on the intermediate structure; At least one additional dielectric layer and at least one additional conductive layer are further stacked above and below the intermediate structure, and then laminated to form a multilayer structure; Alignment is performed using the alignment target, and laser holes are drilled in the multi-layer structure; Remove the temporary support plate to obtain the first sub-plate and the second sub-plate; Electroplating and subsequent processing are performed on the first and second sub-boards.

2. The manufacturing method according to claim 1, characterized in that, The temporary support plate is an insulating carrier plate or a metal carrier plate; the peelable adhesive layer is a micro adhesive layer or a heat-peelable adhesive layer.

3. The manufacturing method according to claim 1, characterized in that, The anti-delamination structure consists of explosion-proof holes distributed around the edge of the plate. The diameter of the explosion-proof holes is 0.2mm to 1.0mm, and the distance between the explosion-proof holes and the edge of the plate is 1.0mm to 5.0mm.

4. The manufacturing method according to claim 1, characterized in that, The method further includes: The panel dimensions are extended outward to form an extension area, the anti-delamination structure is set in the extension area, and the extension area is milled off before the temporary support plate is removed.

5. The manufacturing method according to claim 1, characterized in that, The alignment targets are in two groups, each group includes multiple target patterns, and the distance between adjacent target patterns in the same group is ≥3.0mm; During the alignment process of drilling laser holes in the multi-layer structure using the alignment targets, the laser holes on the upper side of the temporary support plate are aligned using the first set of alignment targets, and the laser holes on the lower side of the temporary support plate are aligned using the second set of alignment targets.

6. The manufacturing method according to claim 1, characterized in that, When creating circuit patterns on the intermediate structure, the circuit patterns located above and below the temporary support plate are exposed using the same set of films, and are flipped horizontally at 180°.

7. The manufacturing method according to claim 1, characterized in that, Before alignment using the alignment target, the method further includes: Remove the additional conductive layer and additional dielectric layer covering the alignment target to expose the alignment target; the removal method is: to remove the additional conductive layer and additional dielectric layer simultaneously by laser ablation, or to first etch away the additional conductive layer by pattern transfer method and then remove the additional dielectric layer by laser ablation.

8. The manufacturing method according to claim 4, characterized in that, The method for removing the temporary support plate is as follows: Mill off the extended region; The temporary support plate can be peeled off directly, or the peelable adhesive layer can be softened by baking before peeling off the temporary support plate.

9. The manufacturing method according to claim 1, characterized in that, The first conductive layer is a conductive layer on the control surface side, and the additional conductive layer is a conductive layer on the LED bead surface.

10. A high-density circuit board for a mini LED light assembly, characterized in that, It is manufactured using the manufacturing method described in any one of claims 1 to 9.

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