Single-sided double-layer aluminum-based circuit board and manufacturing process thereof

Abstract

The application discloses a single-sided double-layer aluminum-based circuit board manufacturing process, which comprises the following steps: S1, punching a hole at a preset position on a PI film; S2, sequentially stacking a copper foil layer, the PI film and the copper foil layer; S3, hot-pressing a first to-be-pressed plate; S4, laser drilling at a preset position on a soft plate and carrying out copper deposition plating; S5, etching lines on the copper foil layers on two sides of the soft plate; S6, sequentially stacking the soft plate, an insulating layer and an aluminum plate; and S7, a pre-product plate sequentially undergoes a solder mask, text, shape and surface process procedure. The PI film is used to replace FR-4, and the excellent performance of the PI film is used to improve the overall performance of the circuit board. The PI film has a low vertical thermal expansion coefficient, and the vertical thermal expansion coefficient of the PI film is close to that of the copper foil layer, so that internal stress, warping and line breakage caused by thermal expansion and contraction mismatch can be reduced in the process of passing through a tinning furnace, and the planar quality and the yield of the circuit board are improved.

Description

Technical Field

[0001] This application relates to the field of aluminum-based circuit board manufacturing technology, and in particular to a single-sided double-layer aluminum-based circuit board and its manufacturing process. Background Technology

[0002] With the rapid development of the electronics industry, especially the display electronics industry, such as televisions and tablets, the performance requirements of circuit boards are becoming increasingly higher, and the wiring on the circuit boards needs to be more and more complex.

[0003] To address the complex routing requirements of circuit boards, double-layer circuit boards were developed. A typical double-layer circuit board structure includes an aluminum plate, FR-4 aluminum foil, a copper foil layer, and another FR-4 aluminum foil layer. The two copper foil layers are connected by openings and copper plating. The copper foil layer carries the circuit structure, while the aluminum plate dissipates heat. However, circuit boards in the display electronics industry are generally very long, and the vertical thermal expansion coefficient of FR-4 is relatively high, which does not match the vertical thermal expansion coefficient of the copper foil layer. During the soldering process, this thermal expansion mismatch leads to uneven thermal expansion, resulting in excessive warpage and unevenness in the aluminum-based circuit board, severely affecting the customer's ability to use it for surface mount technology (SMT).

[0004] Furthermore, during the hole-making process, the laser first ablates the surface copper foil and then acts on the FR-4. The epoxy resin inside the FR-4 rapidly carbonizes, while the glass fiber is melted or left behind. The final hole wall is a mixture of carbonized resin and exposed glass fiber, covered with a layer of conductive carbon black. The carbon black can cause a decrease in the insulation resistance of the FR-4 layer or even a complete short circuit, rendering the circuit board unusable. During subsequent hole metallization (electroplating), it can also prevent the plating layer from bonding well with the carbonized hole wall, easily leading to voids and peeling of the plating, affecting the reliability of the hole and its current transmission capability. Moreover, in high temperature and high humidity environments, carbon black may accelerate copper ion migration (CAF), leading to insulation failure. Carbon black also causes the hole wall to become rough and irregular, affecting signal integrity (especially high-frequency and high-speed signals).

[0005] Therefore, it is necessary to propose a single-sided double-layer aluminum-based circuit board and its manufacturing process to reduce the warpage of the double-layer circuit board and improve its yield rate, which has become an important technical problem that needs to be solved urgently. Summary of the Invention

[0006] This application provides a single-sided double-layer aluminum-based circuit board and its manufacturing process, aiming to solve the problems in the prior art where the vertical thermal expansion coefficient of FR-4 is relatively high and does not match the vertical thermal expansion coefficient of the copper foil layer. During the soldering process, the circuit board will have uneven thermal expansion due to the mismatch in thermal expansion, resulting in serious excessive warpage of the aluminum-based circuit board. In addition, during the hole-making process, the laser first ablates the surface copper foil and then acts on FR-4. The epoxy resin inside FR-4 is rapidly carbonized, while the glass fiber is melted or left behind. The final hole wall is a mixture of carbonized resin and exposed glass fiber, and the surface is covered with a layer of conductive carbon black. The carbon black will seriously affect the yield of the circuit board.

[0007] To achieve the above objectives, this application proposes a manufacturing process for a single-sided double-layer aluminum-based circuit board. The manufacturing process includes the following steps: S1, punching holes at predetermined positions on the PI film; S2, sequentially stacking copper foil layers, PI film, and copper foil layers to form a first board to be pressed; S3, hot-pressing the first board to be pressed to connect the PI film with the copper foil layers on both sides to form a flexible board; S4, laser-drilling holes at predetermined positions on the flexible board and performing copper plating; S5, etching circuits on the copper foil layers on both sides of the flexible board; S6, sequentially stacking the flexible board, insulating layer, and aluminum plate, and repeating S3 to form a pre-finished board; S7, the pre-finished board undergoes solder resist, text, shape, and surface treatment processes to form a finished board.

[0008] In some embodiments, S1 specifically includes the following steps: S11, opening a plurality of first positioning holes in the region near the edge of the PI film; S12, fixing the PI film to a punching device through the plurality of first positioning holes; S13, punching holes in a preset position of the PI film through the punching device.

[0009] In some embodiments, the stacking steps of the copper foil layer, PI film, and copper foil layer in S2 are as follows: S21, a plurality of second positioning holes corresponding to a plurality of first positioning holes are opened in the region of the adjacent edges of the two copper foil layers; S22, the copper foil layer, PI film, and copper foil layer are stacked and arranged so that the second positioning holes on the copper foil layer and the corresponding first positioning holes on the PI film are in a coaxial state.

[0010] In some embodiments, the punching step in step S1 is performed by punching a hole in a preset position on the PI film using a punching device. The punching device includes: a punching table; a longitudinal moving frame movably disposed on the punching table; a transverse moving seat movably disposed on the longitudinal moving frame; and a punching component disposed on the transverse moving seat. The punching component is driven to the preset position on the PI film by the movement of the longitudinal moving frame and the transverse moving seat.

[0011] In some embodiments, the punching device further includes: a mounting plate disposed on a punching platform; a vacuum chamber wall disposed on the mounting plate; a positioning plate mounted on the top of the vacuum chamber wall; multiple positioning pins spaced apart on the positioning plate; and multiple adsorption holes spaced apart on the positioning plate.

[0012] In some embodiments, the punching device further includes: a threaded section, on which the locating pin is provided with a threaded section; a screw barrel, on which an internal thread adapted to the threaded section is provided; and a clamping part, which is disposed at the bottom end of the screw barrel and is integrally formed with the screw barrel.

[0013] In some embodiments, the punching device further includes: a first extension portion, which is provided on the top of the vacuum chamber wall; and a connecting hole, which is provided on both the first extension portion and the positioning plate.

[0014] In some embodiments, the punching device further includes: a thickened portion, wherein the thickened portion is disposed on the lower side of the positioning plate; and a sealing element, wherein a sealing element is disposed between the thickened portion and the vacuum chamber wall, and a sealing element is disposed between the first extended portion and the positioning plate.

[0015] In some embodiments, the punching component includes: a top plate; side plates, with side plates provided on both sides of the top plate, and one side plate connected to a transverse sliding seat; a plurality of punching cylinders, with the plurality of punching cylinders spaced apart on the top plate; an output rod, with an output rod movably disposed within the punching cylinder; a connector, with one end of the connector connected to the output rod; and a punching blade, with the other end of the connector connected to the punching blade.

[0016] Based on another objective of this application, this application also provides a single-sided double-layer aluminum-based circuit board, which is manufactured using the above-described manufacturing process, including: an aluminum plate; an insulating layer disposed on the aluminum plate; two copper foil layers, with two copper foil layers vertically spaced apart on the aluminum plate, one copper foil layer connecting to the insulating layer, and a circuit structure disposed on the copper foil layers; further including: a PI film disposed between two adjacent copper foil layers; punching holes, with punching holes disposed at corresponding positions on the PI film; and laser holes, with laser holes disposed on the copper foil layers corresponding to the punching holes.

[0017] This application proposes a manufacturing process for a single-sided double-layer aluminum-based circuit board, comprising the following steps: S1, punching holes at predetermined positions on a PI film; S2, sequentially stacking a copper foil layer, a PI film, and another copper foil layer to form a first board to be pressed; S3, hot-pressing the first board to be pressed, connecting the PI film with the copper foil layers on both sides to form a flexible board; S4, laser-drilling holes at predetermined positions on the flexible board and performing electroplating with copper plating; S5, etching circuits on the copper foil layers on both sides of the flexible board; S6, sequentially stacking the flexible board, an insulating layer, and an aluminum plate, and repeating S3 to form a pre-finished board; S7, the pre-finished board undergoes solder resist, text, shaping, and surface treatment processes to form a finished board. This application uses a PI film to replace FR-4, leveraging the superior performance of the PI film to improve the overall performance of the circuit board. The PI film has a low vertical coefficient of thermal expansion, close to that of the copper foil layer, which can reduce internal stress, warping, and circuit breakage caused by thermal expansion and contraction mismatch during the solder bath process. This application improves the planar quality and yield of circuit boards. It pre-forms holes in the PI film using a punching method, and then, after flexible circuit board forming, uses laser drilling to create corresponding laser holes in the copper foil layer. Because the punching process involves instantaneous shearing rather than continuous friction, the local temperature does not rise significantly, fundamentally avoiding problems such as melting, softening, resin flow, and carbonization of the PI film during drilling. The hole wall edges maintain the physicochemical properties of the PI film itself, improving the yield and quality of the final circuit board. Laser drilling completely avoids the impact of stress on the copper foil layer and the entire circuit board during drilling, preventing the risk of microcracks and material delamination under stress, and preventing deformation of the copper foil layer under stress, thus improving the yield of the circuit board. Furthermore, the laser drilling process effectively removes burrs formed on the inner wall of the punched holes, improving the quality of the inner wall and providing a perfect foundation for subsequent copper plating, greatly improving plating reliability and yield. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0019] Figure 1 This is a technical roadmap of a single-sided double-layer aluminum-based circuit board manufacturing process according to one embodiment of this application;

[0020] Figure 2 This is a plan view of a single-sided double-layer aluminum-based circuit board according to an embodiment of this application;

[0021] Figure 3This is a cross-sectional view of a single-sided double-layer aluminum-based circuit board according to an embodiment of this application;

[0022] Figure 4 for Figure 3 Enlarged view of part A in the middle;

[0023] Figure 5 This is a three-dimensional structural diagram of the punching device in one embodiment of this application;

[0024] Figure 6 for Figure 5 Enlarged view of part B in the middle;

[0025] Figure 7 for Figure 5 Enlarged view of a section in the middle C;

[0026] Figure 8 This is a side view of a punching device according to an embodiment of this application;

[0027] Figure 9 This is a top view of a punching device according to an embodiment of this application;

[0028] Figure 10 This is a cross-sectional view of a punching device according to an embodiment of this application;

[0029] Figure 11 for Figure 10 Enlarged view of a section in part D;

[0030] Figure 12 This is a cross-sectional view of a punched part in one embodiment of this application;

[0031] Figure 13 This is a plan view of a pre-finished plate in one embodiment of this application.

[0032] In the diagram: 1. Circuit board; 102. Ink layer; 103. Copper foil layer; 104. PI film; 105. Insulating layer; 106. Aluminum plate; 2. Side plate; 3. Electrical connection hole; 4. Electroplating layer; 5. Second end plate; 6. Longitudinal frame; 7. Punching part; 71. Punching cylinder; 72. Output rod; 73. Top plate; 74. Side plate; 75. Connector; 76. Punching blade; 77. Guide part; 8. Horizontal motor; 9. Third connecting plate; 10. Longitudinal screw; 11. Vertical motor; 12. Reinforcing rib; 131. Guide end; 132. Positioning pin; 133. Screw; 134. Press. Tightening part 134, suction hole 14, connecting hole 15, positioning plate 16, longitudinal movement motor 17, first end plate 18, connecting rib 19, longitudinal movement nut 20, sealing element 21, vacuum chamber wall 22, mounting plate 23, first extension part 24, first guide rail 25, first slider 26, first coupling 27, second slider 28, second guide rail 29, second coupling 30, sheet metal area 31, ring edge 32, second positioning hole 33, transverse movement screw 34, transverse movement nut 35, third guide rail 36, vertical movement screw 37. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0034] Example 1

[0035] See Figure 1 As shown, this application discloses a manufacturing process for a single-sided double-layer aluminum-based circuit board 1, which includes the following steps:

[0036] S1. Punch holes at predetermined positions on the PI film 104. The PI film 104 is specifically a thin polyimide PI film 104. The PI film 104 has excellent mechanical properties, with a tensile strength of over 200 MPa and a tensile modulus of over 3 GPa. Furthermore, the PI film 104 has a low vertical coefficient of thermal expansion, approximately 20-50 ppm / ℃. Through formula adjustments, its vertical coefficient of thermal expansion can be made very close to that of the copper foil layer 103 (17 ppm / ℃). During the solder bath process, this reduces internal stress, warping, and circuit breakage caused by thermal expansion and contraction mismatch, improving the planar quality and yield of the circuit board 1. The PI film 104 also exhibits extreme heat resistance, capable of long-term operation in environments above 260℃ without melting or dripping (because it lacks a distinct melting point, it typically begins to decompose and carbonize above 500℃). PI film 104 also possesses stable electrical insulation properties, with a dielectric strength typically between 100-300 kV / mm. This means that even very thin PI film 104 can withstand high voltages of several thousand volts. Furthermore, PI film 104 exhibits good chemical stability, inherent flame retardancy, and radiation resistance. The use of PI film 104 can effectively improve the performance of circuit components in multiple ways.

[0037] An opening is made in the PI film 104 at a predetermined location by punching, facilitating the subsequent formation of electrical connections between adjacent copper foil layers. Since the punching process involves instantaneous shearing rather than continuous friction, the local temperature does not rise significantly, fundamentally avoiding problems such as melting, softening, resin flow, and carbonization that may occur in the PI film 104 during the opening process. The edge of the hole wall maintains the physicochemical properties of the PI film 104 itself, preventing a decrease in insulation resistance or even a complete short circuit caused by the opening. This also promotes good adhesion between the electroplated layer 4 and the hole wall, ensuring the reliability and current transmission capacity of the electroplated layer 4 on the hole wall, and reducing the probability of CAF failure in the circuit board 1. This improves the yield and quality of the final formed circuit board 1.

[0038] In this embodiment, the PI film 104 is an adhesive-free PI film 104, and the copper foil layer 103 is directly bonded to the PI film 104 through hot pressing or other special processes. Before punching and hot pressing, the PI film 104 must be baked in a high-temperature oven for several hours to completely remove absorbed moisture. This is to avoid significant deformation of the PI film 104 during punching or hot pressing.

[0039] S2. Copper foil layer 103, PI film 104 and copper foil layer 103 are stacked in sequence to form the first plate to be pressed;

[0040] S3. Hot-press the first platen to be pressed, so that the PI film 104 is connected with the copper foil layers 103 on both sides to form a flexible plate; the copper foil layer 103, PI film 104, and copper foil layer 103 are aligned and stacked vertically to form the first platen to be pressed. During the hot-pressing process, the temperature needs to be raised and lowered slowly to allow the film material to fully relax the stress in each temperature range, reduce the residual internal stress caused by the CTE difference, and reduce the deformation of the PI film 104; more specifically, this step adopts a programmed hot-pressing with segmented heating. First, under a low pressure of 5-10 MPa, preheat to 120°C at a rate of 5-8°C / min and hold for 30 minutes to ensure full adhesion of the PI film and copper foil and to remove interlayer air. Then, increase the pressure to 20-30 MPa while simultaneously raising the temperature to 180-200°C at a rate of 3-5°C / min and holding for 90-120 minutes to ensure full bonding between the PI film and copper foil. Finally, while maintaining pressure, slowly cool to below 60°C at a rate not exceeding 5°C / min before demolding. Through the above pressure and temperature curve control, especially in the pre-pressing stage, severe lateral flow of the material under high temperature and pressure can be effectively prevented, thus ensuring that the positional accuracy and shape of the pre-punched holes on the PI film 104 do not shift or deform after hot pressing. Furthermore, a silicone pad, kraft paper, or other buffer material is placed between the pressure plate of the hot press and the first plate to be pressed to evenly distribute the pressure, absorb minor unevenness, prevent excessive local pressure, and further reduce the deformation of the PI film 104 during the hot pressing process. This also prevents the pre-punched holes from deforming during the hot pressing process.

[0041] S4. Laser-drill holes at predetermined positions on the flexible circuit board and perform copper plating. Specifically, a short-pulse ultraviolet laser is preferred for this step. Because ultraviolet lasers have short wavelengths, they are cold-processed with small focused spots. Their high-energy photons directly break the molecular bonds of the material, resulting in a minimal heat-affected zone. This avoids thermal damage or carbonization to the PI film 104 at the hole edge, maintaining the excellent insulation performance of the PI film. To achieve burr removal and hole wall optimization, the laser process parameters are controlled as follows: laser power is controlled at 10-20W, pulse frequency is set to 30-50kHz, and scanning speed is 300-500mm / s. This combination of high frequency and low single-pulse energy ablates the copper foil layer 103, instantly vaporizing any tiny burrs that may have formed at the PI film hole edge due to copper foil extension during the previous punching step, without transferring a large amount of heat to the PI film. Multiple scans of the laser beam can also refine the hole walls, forming smooth, residue-free inner walls. This provides a uniform and strongly bonded adhesion surface for subsequent copper plating, significantly improving plating reliability and yield. After the flexible circuit board is formed, laser holes are created at predetermined positions on the board using laser drilling. These laser holes are located on two copper foil layers 103. The laser holes on the two copper foil layers 103 and the corresponding punched holes on the PI film 104 form electrical connection holes 3 connecting the two copper foil layers 103. Copper plating is applied to the inner walls of the electrical connection holes 3 to form an electroplated layer 4, thus establishing an electrical connection between the two copper foil layers 103. Laser drilling completely avoids the impact of stress on the copper foil layers 103 and the entire circuit board 1 during drilling, preventing the risk of microcracks and material delamination in the circuit board 1 under stress. It also prevents deformation of the copper foil layers 103 under stress, improving the yield of the circuit board 1. Furthermore, the laser drilling process can effectively remove burrs formed on the inner wall of the hole during the punching process, improving the quality of the inner wall of the hole and providing a perfect foundation for subsequent copper plating, greatly improving the reliability and yield of the plating.

[0042] S5. Etch the circuit on the copper foil layer 103 on both sides of the flexible circuit board. During the etching process, the circuit design pattern on the copper foil layer 103 needs to be transferred to the photosensitive material first. Then, the photo-pattern is exposed on the copper foil layer 103 by ultraviolet light. The unexposed areas are removed by the developer to form the circuit pattern. The unwanted copper foil is dissolved by chemical solution (such as ferric chloride, copper sulfate, etc.). Finally, the chemical residues from the etching are removed to avoid affecting the subsequent processes. The required circuit structure can then be etched on the copper foil layer 103 on both sides of the flexible circuit board.

[0043] S6. A flexible circuit board, an insulating layer 105, and an aluminum plate 106 are sequentially stacked, and S3 is repeated to form a pre-finished board. The insulating layer 105 is preferably made of semi-cured thermally conductive silicone. Semi-cured thermally conductive silicone has excellent electrical insulation properties, and through its good thermal conductivity, it quickly transfers heat to the aluminum plate 106. During the operation of the circuit board 1, the copper foil layer 103 generates a certain amount of heat. The insulating layer 105, made of semi-cured thermally conductive silicone, can effectively dissipate the heat generated on the copper foil layer 103, ensuring the thermal stability of the single-sided double-layer aluminum-based circuit board 1 and extending its service life. The hot-pressing process is similar to the hot-pressing process in S3 and will not be repeated here.

[0044] S7. The pre-finished board undergoes solder resist, text, shaping, and surface treatment processes sequentially to form the finished board. Solder resist is a crucial process where a solder resist layer is applied to the circuit board 1 to protect the copper foil layer 103 from oxidation and prevent short circuits during soldering. The solder resist layer is typically green. Text is the printing of characters onto the solder resist layer, used to identify components, pin numbers, and other important information on the copper substrate. This is essential for later assembly and maintenance. Surface treatments for single-sided double-layer aluminum-based circuit boards 1 typically include tin plating, gold plating, and immersion silver plating to improve soldering performance and prevent oxidation. Different surface treatments are suitable for different operating environments and cost requirements. Shaping involves milling the required shape of the board material on a milling machine.

[0045] Among them, see Figure 13 As shown, the finished board after solder masking includes a board material area 31 and a ring edge 32. Multiple circuit boards 1 are arranged within the board material area 31, and the ring edge 32 is used for positioning the finished board. During the shaping process, the ring edge 32 needs to be cut off.

[0046] Specifically, this application replaces FR-4 with PI film 104, leveraging the superior performance of PI film 104 to improve the overall performance of circuit board 1. PI film 104 has a low vertical coefficient of thermal expansion, close to that of copper foil layer 103. During the solder bath process, it reduces internal stress, warping, and circuit breakage caused by thermal expansion and contraction mismatch, thus improving the planar quality and yield of circuit board 1. This application pre-forms holes in PI film 104 using a punching method. After flexible circuit board forming, corresponding laser holes are then created in copper foil layer 103 using laser drilling. Because the punching process involves instantaneous shearing rather than continuous friction, the local temperature does not rise significantly, fundamentally avoiding melting, softening, resin flow, and carbonization problems that may occur with PI film 104 during hole drilling. The hole wall edges maintain the physicochemical properties of PI film 104, improving the yield and quality of the final formed circuit board 1. Laser drilling completely avoids the impact of stress on the copper foil layer 103 and the entire circuit board 1 during drilling, preventing the risk of microcracks and material delamination in the circuit board 1 under stress. It also prevents deformation of the copper foil layer 103 under stress, improving the yield of the circuit board 1. Furthermore, the laser drilling process effectively removes burrs formed on the inner wall of the punched hole during the punching process, improving the quality of the inner wall and providing a perfect foundation for subsequent copper plating, greatly enhancing plating reliability and yield.

[0047] In some embodiments, S1 specifically includes the following steps: S11, forming a plurality of first positioning holes in the region near the edge of the PI film 104; the plurality of first positioning holes are all formed on the ring edge 32, and the first positioning holes can be formed by laser drilling. Since laser drilling has high positional accuracy and precise hole shape, it is beneficial to improve the accuracy of positioning the PI film 104 through the first positioning holes. Since the ring edge 32 region will be removed later, even if carbonization occurs in the positioning hole region of the PI film 104, it will not affect the quality of the final formed circuit board 1. S12, fixing the PI film 104 to the punching equipment through the plurality of first positioning holes; fixing the PI film 104 through the first positioning holes can quickly and accurately position the PI film 104. S13, punching holes in the PI film 104 at preset positions using the punching equipment. The laser holes on the two copper foil layers 103 and the corresponding punched holes on the PI film 104 form an electrical connection hole 3 connecting the two copper foil layers 103. The inner wall of the electrical connection hole 3 is plated with copper to form an electroplated layer 4, thereby forming an electrical connection between the two copper foil layers 103.

[0048] In some embodiments, the stacking steps of the copper foil layer 103, PI film 104, and copper foil layer 103 in S2 are as follows: S21, a plurality of second positioning holes 33 corresponding to a plurality of first positioning holes are formed in the region near the edge of the two copper foil layers 103; S22, the copper foil layer 103, PI film 104, and copper foil layer 103 are stacked and arranged so that the second positioning holes 33 on the copper foil layer 103 and the corresponding first positioning holes on the PI film 104 are coaxial. The second positioning holes 33 are also formed by laser drilling. The formation of the second positioning holes 33 helps to ensure that the copper foil layer 103 and the PI film 104 are completely overlapped. In the subsequent laser drilling process, the first positioning holes and the second positioning holes 33 are also used as positioning references to effectively ensure that the laser-drilled holes and the corresponding punched holes are coaxial.

[0049] Preferably, the aluminum plate 106 has a plurality of third positioning holes corresponding to a plurality of first positioning holes in the circumferential edge 32 region, and the insulating layer 105 has a plurality of fourth positioning holes corresponding to a plurality of first positioning holes in the circumferential edge 32 region.

[0050] See Figure 5 , Figure 7 , Figure 8 , Figure 9 and Figure 10 As shown, in some embodiments, the punching step in step S1 is performed by punching a hole in a preset position on the PI film using a punching device. The punching device includes: a punching table, which is composed of a first end plate 18, a second end plate 5, and a connecting rib 19 connecting the first end plate 18 and the second end plate 5. The punching table is the structural foundation of the punching device, and other structures on the punching device are directly or indirectly mounted on the punching table. The length direction of the punching table is longitudinal, and the width direction is transverse; a longitudinal moving frame 6, which is movably disposed on the punching table; a transverse moving seat, which is movably disposed on the longitudinal moving frame 6; and a punching component 7, which is disposed on the transverse moving seat. By moving the longitudinal moving frame 6 and the transverse moving seat, the punching component 7 is driven to the preset position on the PI film. The longitudinal frame 6 is movable along the longitudinal direction and is set on the punching table. The transverse seat is movable along the transverse direction and is set on the transverse seat. In the punching process, the longitudinal movement of the longitudinal frame 6 and the transverse movement of the transverse seat allow the punching part 7 to be moved to any position on the punching table for punching, so as to punch at the preset position of the PI film 104.

[0051] Specifically, a longitudinal movement motor 17 is detachably mounted on the first end plate 18 via screws. The output end of the longitudinal movement motor 17 is connected to a longitudinal movement screw 10 via a first coupling 27. A longitudinal movement nut 20 is screwed onto the longitudinal movement screw 10 and is mounted to the longitudinal movement frame 6 via screws. Two first guide rails 25 are connected between the first end plate 18 and the second end plate 5. The two first guide rails 25 are located on both sides of the longitudinal movement screw 10. A first slider 26 is movably connected to both first guide rails 25. The first slider 26 and the longitudinal movement nut 20 are connected as one unit via a first connecting plate. The first connecting plate is detachably connected to the first slider 26 and the longitudinal movement nut 20 via screws. The longitudinal movement motor 17 outputs torque to drive the longitudinal movement screw 10 to rotate, thereby driving the longitudinal movement nut 20 to move longitudinally and the longitudinal movement frame 6 to move longitudinally. The structural design of the first guide rails 25 and the first slider 26 helps to improve the stability of the longitudinal movement frame 6 during movement.

[0052] Preferably, the longitudinal frame 6 is provided with reinforcing ribs 12 to improve the structural strength of the longitudinal frame 6.

[0053] A transverse motor 8 is detachably mounted on the longitudinal frame 6 via screws. The output end of the transverse motor 8 is connected to a transverse screw 34 via a second coupling 30. A transverse nut 35 is screwed onto the transverse screw 34. Two second guide rails 29 are connected to the longitudinal frame 6, located on either side of the transverse screw 34. A second slider 28 is movably connected to each of the two second guide rails 29. The second slider 28 and the transverse nut 35 are connected as one unit via a second connecting plate. The second connecting plate is detachably connected to the second slider 28 and the transverse nut 35 via screws. The second connecting plate is also detachably connected to the transverse seat via screws. The torque output by the transverse motor 8 drives the transverse screw 34 to rotate, thereby causing the transverse nut 35 to move laterally and the transverse seat to move laterally. The structural design of the second guide rails 29 and the second slider 28 helps to improve the stability of the transverse seat during movement.

[0054] In this embodiment, a vertical movement motor 11 is detachably mounted on the horizontal movement base via screws. The output end of the vertical movement motor 11 is connected to a vertical movement screw 37 via a third coupling, and a vertical movement nut is screwed onto the vertical movement screw 37. Two third guide rails 36 are connected to the horizontal movement base, and the two third guide rails 36 are respectively located on both sides of the vertical movement screw 37. A third slider is movably connected to both third guide rails 36. The second slider 28 and the horizontal movement nut 35 are connected as one unit via a third connecting plate 9. The third connecting plate 9 is detachably connected to the third slider and the vertical movement nut via screws. The third connecting plate 9 is also detachably connected to the punched part 7 via screws. The vertical movement motor 11 outputs torque to drive the vertical movement screw 37 to rotate, thereby driving the vertical movement nut to move vertically and driving the punched part 7 to move vertically. The structural design of the third guide rails 36 and the third slider helps to improve the stability of the punched part 7 during movement. Vertical position adjustment is beneficial for adjusting the vertical position of the punched part 7. During the punching process, when dealing with PI films 104 of different thicknesses, it is necessary to adjust the vertical height of the punching part 7 appropriately to adjust the end point of the punching stroke. This will effectively punch holes in the PI film 104 while avoiding hard contact between the punching blade 76 and the positioning plate 16, thus improving the service life of the punching part 7.

[0055] See Figure 5 , Figure 6 , Figure 8 , Figure 9 , Figure 10 and Figure 11As shown, in some embodiments, the punching device further includes: a mounting plate 23, which is disposed on the punching platform; the mounting plate 23 is connected to the first end plate 18 and the second end plate 5 by screws; a vacuum chamber wall 22, which is disposed on the mounting plate 23; the vacuum chamber wall 22 is integrally formed with the mounting plate 23, and a vacuum chamber is disposed inside the vacuum chamber wall 22; a suction hole communicating with the vacuum chamber is disposed on the side of the vacuum chamber wall 22, and the suction hole is connected to a suction pump, which extracts air from the vacuum chamber to make the vacuum chamber be in a state of super negative pressure; a positioning plate 16, which is installed at the top of the vacuum chamber wall 22; the positioning plate 16 is located at the top of the vacuum chamber wall 22 and is used to seal the vacuum chamber wall 22 to ensure the airtightness of the vacuum chamber; and multiple positioning pins 132, which are spaced apart on the positioning plate 16; the multiple positioning pins 132 are used to position the PI film 104 so that the PI film 104 is in a preset position on the positioning plate 16. Multiple adsorption holes 14 are spaced apart on the positioning plate 16. The adsorption holes 14 are staggered from the punching positions. The PI film 104 is adsorbed through the adsorption holes 14 and the negative pressure in the vacuum chamber. During the punching process, the punching blade 76 shears the PI film 104, and since the positioning pins 132 are far from the punching position, the PI film 104 will undergo slight deformation during the punching process, affecting the punching accuracy. The setting of multiple adsorption holes 14 can significantly increase the fixing points, enhance the fixing effect of the PI film 104, reduce the deformation of the PI film 104 during the punching process, and thus improve the punching accuracy.

[0056] In this embodiment, a guide end 131 is provided at the end of the positioning pin 132 away from the positioning plate 16. The guide end 131 facilitates the positioning pin 132 to engage with the corresponding first positioning hole on the PI film 104. A ring of adsorption holes 14 is provided in the circumferential edge 32 region. In the sheet material area 31 region, the adsorption holes 14 are spaced apart from the punching holes to avoid the punching holes affecting the airtightness of the vacuum chamber.

[0057] See Figure 5 , Figure 6 , Figure 8 , Figure 9 , Figure 10 and Figure 11 As shown, in some embodiments, the punching device further includes: a threaded section, the positioning pin 132 having a threaded section with external threads; a screw barrel 133 having internal threads adapted to the threaded section, and internal threads adapted to the external threads of the threaded section within the screw barrel 133; and a clamping part 134, located at the bottom end of the screw barrel 133, integrally formed with the screw barrel 133, the clamping part 134 being used to press tightly against the upper surface of the PI film 104, the clamping part 134 effectively preventing the edges of the PI film 104 from lifting, reducing the deformation of the PI film 104 during the punching process, and improving the punching quality.

[0058] In this embodiment, a layer of soft aluminum foil is also provided on the positioning plate 16, and the adsorption hole 14 extends to the soft aluminum foil. The soft aluminum foil is provided with a fifth positioning hole adapted to the positioning pin 132. The pressing part 134 presses the soft aluminum foil and the PI film 104 onto the positioning plate 16. During the punching process, the soft aluminum foil can effectively provide a buffer for the punching blade 76, preventing the punching blade 76 from damaging the positioning plate 16 and improving the service life of the positioning plate 16. Furthermore, the soft aluminum foil can achieve mirror flatness during rolling, and the soft aluminum foil itself has a certain rigidity, which is sufficient to "ignore" the micro-unevenness on the positioning plate 16, improve the flatness of the PI film 104, and thus improve the punching accuracy.

[0059] See Figure 5 , Figure 6 , Figure 10 and Figure 11 As shown, in some embodiments, the punching device further includes: a first extension portion 24, which is provided on the top of the vacuum chamber wall 22; Firstly, the first extension portion 24 can increase the contact area between the vacuum chamber wall 22 and the positioning plate 16, thereby dispersing the stress on the positioning plate 16 during the punching process, reducing the impact of the stress on the sealing performance between the positioning plate 16 and the vacuum chamber wall 22, thereby improving the sealing effect between the positioning plate 16 and the vacuum chamber wall 22, avoiding the loss of adhesion to the PI film 104 due to sealing failure, and improving the stability during the punching process. Secondly, the first extension portion 24 helps to extend the sealing path between the positioning plate 16 and the vacuum chamber wall 22, making it more difficult for external air to enter the vacuum chamber. Connecting holes 15 are provided on both the first extension portion 24 and the positioning plate 16. The positioning plate 16 is connected to the vacuum chamber wall 22 by bolts. When drilling on different types of PI films 104, it is necessary to replace the corresponding positioning plate 16, enhancing the compatibility of the punching device with different types of PI films 104 and improving the practicality of the punching device.

[0060] Preferably, the top end of the first extension 24 is provided with a plurality of spaced sealing protrusions, and the positioning plate 16 is provided with a plurality of sealing grooves adapted to the sealing protrusions. The structural design of the sealing protrusions and sealing grooves further increases the contact area between the vacuum cavity wall 22 and the positioning plate 16.

[0061] See Figure 5 , Figure 6 , Figure 10 and Figure 11As shown, in some embodiments, the punching device further includes: a thickened portion, wherein a thickened portion is provided on the lower side of the positioning plate 16; the thickened portion is used to enhance the structural strength of the positioning plate 16, preventing the positioning plate 16 from deforming under long-term impact loads, thus affecting the punching accuracy of the PI film 104; and the thickened portion helps to increase the sealing path between the positioning plate 16 and the vacuum chamber wall 22, making it more difficult for external air to enter the vacuum chamber. A sealing element 21 is provided between the thickened portion and the vacuum chamber wall 22, and between the first extension portion 24 and the positioning plate 16. The sealing element 21 is a sealing ring, used to ensure the sealing performance between the vacuum chamber wall 22 and the positioning plate 16.

[0062] Preferably, two sealing elements 21 are provided at intervals between the thickened portion and the vacuum chamber wall 22, and two sealing elements 21 are provided at intervals between the vacuum chamber wall 22 and the positioning plate 16.

[0063] See Figure 5 , Figure 8 , Figure 9 , Figure 10 and Figure 12 As shown, in some embodiments, the punching component 7 includes: a top plate 73; side plates 74, with side plates 74 provided on both sides of the top plate 73, one side plate 74 being connected to a transverse sliding seat; the side plates 74 are mounted to the top plate 73 by screws, and the side plates 74 are connected to a third connecting plate 9 by screws, thereby achieving the connection between the third connecting plate 9 and the punching component 7. A plurality of punching cylinders 71 are spaced apart on the top plate 73; the punching cylinders 71 are mounted to the top plate 73 by screws. An output rod 72 is movably disposed within the punching cylinder 71; the output rod 72 can extend or retract from the punching cylinder 71 under the control of the gas station. When the output rod 72 extends from the punching cylinder 71, it drives the punching blade 76 to punch towards the PI film 104, forming a punch in the PI film 104. A connector 75 is provided, with one end connected to an output rod 72; the connector 75 is screwed to the output rod 72. A punching blade 76 is also provided, with the other end connected to the connector 75. The punching blade 76 is screwed to the connector 75. The arrangement of multiple punching cylinders 71 allows for the installation of different specifications of punching blades 76 on different punching cylinders 71, enabling the processing of punches of different specifications on the PI film 104, thus improving the practicality of the punching equipment.

[0064] In this embodiment, a guide member 77 is connected to the side plate 74 by screws. The side of the guide member 77 away from the side plate 74 is provided with an arc-shaped surface adapted to the connector 75. The arc-shaped surfaces of the guide members 77 on the two side plates 74 effectively guide the connector 75 and the punching blade 76, improving the punching accuracy. The bottom of the punching blade 76 is provided with a tapered portion to facilitate better insertion of the punching blade 76 into the PI film 104.

[0065] Example 2

[0066] In this embodiment, the parts that are the same as in Embodiment 1 are given the same reference numerals, and the same text descriptions are omitted.

[0067] See Figure 2 , Figure 3 and Figure 4As shown, this embodiment discloses a single-sided double-layer aluminum-based circuit board 1, which is manufactured using the process described in Embodiment 1. It includes: an aluminum plate 106; an insulating layer 105 disposed on the aluminum plate 106; two copper foil layers 103, with two copper foil layers 103 vertically spaced on the aluminum plate 106, one copper foil layer 103 connecting to the insulating layer 105, and a circuit structure disposed on the copper foil layers 103; it also includes: a PI film 104, with a PI film 104 disposed between adjacent copper foil layers 103; the PI film 104 has excellent mechanical properties, with a tensile strength exceeding 200 MPa and a tensile modulus exceeding 3 GPa, and a low vertical coefficient of thermal expansion, approximately 20-50 ppm / ℃. Through formula adjustment, the vertical coefficient of thermal expansion can be adjusted to be similar to that of the copper foil layers 103 (17...). The PI film (ppm / ℃) is very close to the PI film, which reduces internal stress, warping, and circuit breakage caused by thermal expansion and contraction mismatch during the soldering process. This improves the planar quality and yield of the circuit board 1. Furthermore, the PI film 104 has extreme heat resistance, capable of long-term operation in environments above 260℃ without melting or dripping (because it has no obvious melting point, it typically begins to decompose and carbonize above 500℃). The PI film 104 also has stable electrical insulation properties, with a dielectric strength typically between 100-300kV / mm, meaning that even a very thin PI film 104 can withstand thousands of volts of high voltage. The PI film 104 also has good chemical stability, inherent flame retardancy, and radiation resistance. The use of the PI film 104 can effectively improve the performance of the circuit section in several ways. Perforation: Perforations are provided in the PI film 104 at corresponding positions; Laser-cut holes: Laser-cut holes corresponding to the perforations are provided on the copper foil layer 103. Laser-drilled holes are formed on two copper foil layers 103. These laser-drilled holes and corresponding punched holes on the PI film 104 form electrical connection holes 3 connecting the two copper foil layers 103. Copper plating is applied to the inner wall of the electrical connection holes 3 to form an electroplated layer 4, thereby establishing an electrical connection between the two copper foil layers 103. Laser drilling completely avoids the impact of stress on the copper foil layers 103 and the entire circuit board 1 during drilling, preventing the risk of microcracks and material delamination on the circuit board 1 under stress. It also prevents deformation of the copper foil layers 103 under stress, improving the yield of the circuit board 1. Furthermore, the laser drilling process effectively removes burrs formed on the inner wall of the punched holes during the punching process, improving the quality of the inner wall and providing a perfect foundation for subsequent copper plating, greatly improving plating reliability and yield. Furthermore, since the punching process is an instantaneous shearing rather than continuous friction, the local temperature will not rise significantly, thus fundamentally avoiding the melting, softening, glue flow and carbonization problems that may occur in PI film 104 when opening holes.The edges of the hole walls maintain the physicochemical properties of the PI film 104 itself, avoiding a decrease in the insulation resistance of the PI film 104 or even a complete short circuit caused by the opening. This also facilitates a good bond between the electroplated layer 4 and the hole walls, ensuring the reliability and current transmission capacity of the electroplated layer 4 on the hole walls, and reducing the probability of CAF failure in the circuit board 1. This improves the yield and quality of the final formed circuit board 1.

[0068] In this embodiment, an ink layer 102 is also provided on the outer copper foil layer 103. The ink layer 102 is used to form an isolation between the external environment and the outer copper foil layer 103. Side plates 2 are provided on both sides of the multiple circuit boards 1. The side plates 2 are used to connect the multiple circuit boards 1. The provision of side plates 2 is beneficial to the transportation of the circuit boards 1.

[0069] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A manufacturing process for a single-sided double-layer aluminum-based circuit board, characterized in that, The manufacturing process includes the following steps: S1. Punch holes at predetermined positions on the PI film; S2. Copper foil layer, PI film, and copper foil layer are stacked in sequence to form the first plate to be pressed; S3. Hot-press the first platen to be pressed, so that the PI film is connected with the copper foil layers on both sides to form a flexible board; S4. Laser drilling is performed at a preset position on the flexible board, followed by copper plating. S5. Etch lines on the copper foil layers on both sides of the flexible circuit board; S6. Stack the flexible board, insulating layer, and aluminum plate in sequence, and repeat S3 to form a pre-finished board; S7. The pre-finished panels undergo solder resist, text, shape and surface processing steps in sequence to form the finished panels.

2. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 1, characterized in that, The above S1 specifically includes the following steps: S11. A plurality of first positioning holes are made in the region near the edge of the PI film; S12. Fix the PI film to the punching equipment through a plurality of the first positioning holes; S13. Punch holes in the PI film at a preset position using the punching device.

3. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 2, characterized in that, The specific lamination steps of the copper foil layer, PI film, and copper foil layer in S2 above are as follows: S21. A plurality of second positioning holes corresponding to a plurality of first positioning holes are opened in the region near the edge of the two copper foil layers; S22. Stack the copper foil layer, PI film, and copper foil layer together, and make the second positioning hole on the copper foil layer and the corresponding first positioning hole on the PI film coaxial.

4. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 1, characterized in that, The punching step in step S1 involves punching holes in the PI film at predetermined positions using a punching device, wherein the punching device includes: Punching station; The longitudinal moving frame (6) is movably disposed on the punching table; A transverse sliding seat is movably disposed on the longitudinal sliding frame (6); The punched part (7) is disposed on the transverse moving seat; by moving the longitudinal moving frame (6) and the transverse moving seat, the punched part (7) is driven to reach the preset position of the PI film.

5. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 4, characterized in that, The punching equipment also includes: Mounting plate (23), which is disposed on the punching platform; Vacuum cavity wall (22), the vacuum cavity wall (22) is disposed on the mounting plate (23); Positioning plate (16), the positioning plate (16) is installed on the top of the vacuum chamber wall (22); Multiple positioning pins (132) are spaced apart on the positioning plate (16); Multiple adsorption holes (14) are provided on the positioning plate (16) at intervals.

6. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 5, characterized in that, The punching equipment also includes: The locating pin (132) is provided with a threaded section; A screw barrel (133) is provided with an internal thread adapted to the threaded section; A clamping part (134) is disposed at the bottom end of the screw barrel (133), and the clamping part (134) is integrally formed with the screw barrel (133).

7. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 5, characterized in that, The punching equipment also includes: The first extension (24) is provided on the top of the vacuum cavity wall (22). Connection hole (15) is provided on both the first extension part (24) and the positioning plate (16).

8. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 7, characterized in that, The punching equipment also includes: The thickened portion is provided on the lower side of the positioning plate (16); A sealing element (21) is provided between the thickened portion and the vacuum chamber wall (22), and the sealing element (21) is provided between the first extended portion (24) and the positioning plate (16).

9. The manufacturing process of a single-sided double-layer aluminum-based circuit board according to claim 4, characterized in that, The punched part (7) includes: Top plate (73); Side plate (74), both sides of the top plate (73) are provided with the side plate (74), and one of the side plates (74) is connected to the transverse sliding seat; A plurality of punching cylinders (71) are spaced apart on the top plate (73). Output rod (72), which is movably disposed inside the punching cylinder (71); A connector (75), one end of which is connected to the output rod (72); The other end of the connecting piece (75) is connected to the punching edge (76).

10. A single-sided double-layer aluminum-based circuit board, wherein the single-sided double-layer aluminum-based circuit board is manufactured using the processing method according to any one of claims 1-9, comprising: Aluminum plate (106); An insulating layer (105) is disposed on the aluminum plate (106); Two copper foil layers (103) are arranged vertically on the aluminum plate (106), one of the copper foil layers (103) is connected to the insulating layer (105), and a circuit structure is provided on the copper foil layer (103); Its characteristic is that it further includes: PI film (104), the PI film (104) is disposed between two adjacent copper foil layers (103); The PI film (104) has punched holes at corresponding positions; Laser holes are provided on the copper foil layer (103) that correspond to the punching holes.

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