High current carrying copper-inlaid bulk circuit board
By combining single-sided etched core board and bare board, the problem of mismatch in copper block embedding and thickness control in copper-embedded power circuit boards is solved, achieving high current carrying capacity and reliability, and reducing the risk of delamination and residual adhesive defect rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANG XI XU SHENG DIAN ZI GU FEN YOU XIAN GONG SI
- Filing Date
- 2025-08-06
- Publication Date
- 2026-07-14
AI Technical Summary
Existing copper-embedded power circuit boards have problems such as the mismatch between the thermal expansion coefficients of the copper block and the substrate, resulting in delamination; difficulty in controlling the thickness of multi-layer core boards; and residual adhesive residue from controlled-depth milling affecting conductivity.
The process employs a combination of single-sided etching of the core board, copper slotting in the bare board, and rivet fixing. The first core board, the bare board, and the second core board are fixed by rivets, copper blocks are embedded, and copper plating is deposited in the through holes to enhance bonding and conductivity.
It achieves high-precision embedding of copper blocks and controllable pressing thickness, reducing the risk of delamination and residual adhesive defects, and improving current carrying capacity and conductivity.
Smart Images
Figure CN224503613U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuit board technology, specifically to a high current-carrying copper-embedded circuit board. Background Technology
[0002] Copper-embedded power supply circuit boards have a wide range of applications in the market, especially in 5G communication equipment. Due to their excellent heat dissipation performance and space-saving features, copper-embedded power supply circuit boards are increasingly used in devices requiring high-performance heat dissipation. With the popularization of 5G communication and the future advancement of 6G technology, the market demand for copper-embedded power supply circuit boards will further increase.
[0003] The main technical defects of existing copper-embedded power circuit boards are:
[0004] 1. Copper block embedding process: The traditional method uses resin to fill and fix the copper block, which easily leads to a mismatch in the thermal expansion coefficients of the copper block and the substrate, and delamination is easy after high-temperature pressing (defect rate > 15%).
[0005] 2. When laminating and stacking copper blocks on multi-layer core boards, it is difficult to control the total thickness tolerance within ±0.2mm (the conventional process fluctuates within ±0.35mm);
[0006] 3. Residual adhesive residue or damage to the copper block surface during controlled-depth milling requires an additional cleaning process and also affects high-current conduction performance.
[0007] Therefore, it is necessary to provide a new process to solve the above-mentioned technical problems. Utility Model Content
[0008] The technical problem to be solved by this utility model is to provide a high current-carrying copper block embedded circuit board that can achieve high-precision copper block embedding, controllable lamination thickness and no adhesive residue, thus solving the problems of current carrying capacity and reliability of traditional power cord boards.
[0009] The technical solution of this utility model is:
[0010] A high current-carrying copper-embedded circuit board includes a multilayer circuit board formed by lamination, a through hole formed through the multilayer circuit board, a first copper plating layer deposited on the wall of the through hole, and a second copper plating layer and a third copper plating layer deposited on the surface of the outer copper foil of the multilayer circuit board, wherein the second copper plating layer and the third copper plating layer are designed with outer circuits.
[0011] The multilayer circuit board includes a first core board, a light board and a second core board stacked in sequence, and a copper block with one end embedded in the light board and the other end extending out of the light board. The first core board and the second core board are etched on one side to form the inner layer circuit. The first core board, the light board and the second core board are fixed by rivets and then pressed together.
[0012] The high current-carrying copper-embedded block circuit board also includes a first heat dissipation hole formed through the second copper plating layer and the first core board, and a second heat dissipation hole formed through the third copper plating layer and the second core board. The first heat dissipation hole and the second heat dissipation hole are distributed on two opposite sides of the copper-embedded block.
[0013] Furthermore, the light plate is formed by double-sided etching of the core board, and the double-sided copper layers of the light plate are completely removed.
[0014] Furthermore, the light board is provided with a copper embedding groove, and one end of the copper embedding block is embedded in the copper embedding groove.
[0015] Furthermore, the thickness of the light plate is 1.0 mm, the thickness of the copper-embedded block is 1.0 mm ± 0.02 mm, and the size of the contact surface between the copper-embedded groove and the copper-embedded block is equal to the size of the copper-embedded block ± 0.05 mm.
[0016] Furthermore, micro-adhesive films are attached to the opposite sides of the copper-embedded block. The micro-adhesive films are polyimide films with a thickness of 50 μm.
[0017] Furthermore, the end of the copper-embedded block extending outside the copper-embedded groove is bent to form a bent portion, and the bending radius is 1.0mm±0.05mm.
[0018] Furthermore, the thickness of the first copper plating layer is ≥30µm, and the thicknesses of the second and third copper plating layers are ≥72µm.
[0019] Furthermore, there are multiple first and second heat dissipation holes.
[0020] Furthermore, the first core board includes an epoxy resin material layer, a first core board copper foil and a second core board copper foil stacked on both sides of the first epoxy resin material layer;
[0021] The second core board includes a second epoxy resin material layer, a third core board copper foil and a fourth core board copper foil stacked on both sides of the second epoxy resin material layer;
[0022] In this process, the copper foils of the first and fourth core boards are all copper, while the copper foils of the second and third core boards are formed into inner layer circuits through etching.
[0023] Compared with the prior art, the high current-carrying copper-embedded circuit board provided by this utility model has the following advantages:
[0024] I. The high current-carrying copper-embedded circuit board of this utility model adopts single-sided etching for the first core board and the second core board to form single-sided circuit protection, and adopts open copper grooves in the bare board to embed the copper blocks, which can reduce the deformation of the pressing and the warpage rate is <0.15%, which is better than the warpage of traditional double-sided etching (the warpage of traditional through-face etching is more than 0.3%). The pressing thickness tolerance is ±0.2mm.
[0025] II. The high current-carrying copper block circuit board of this utility model uses rivets to fix the first core board, the bare board and the second core board, with interlayer offset ≤25um, which can achieve copper block alignment accuracy of ±25um.
[0026] Third, the high current-carrying copper-embedded circuit board of this utility model adopts a combination of rivet fixing and open board slotting, which enhances the interlayer bonding force, reduces the risk of delamination, and reduces the defect rate from 15% to 0.1%.
[0027] IV. Compared with existing technologies, the high current-carrying copper-embedded circuit board of this utility model eliminates the need for laser drilling and special filler materials, reducing costs by approximately 25%; the residual adhesive residue area at the edge of the copper-embedded block is <0.01mm. 2 The residual adhesive defect rate is <0.1%.
[0028] V. The high current-carrying copper-embedded circuit board of this utility model has a bending angle tolerance of ±0.5° and a current carrying capacity of up to 50A (temperature rise <15°), which is better than the 30A limit of traditional PCBs. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 This is a schematic diagram of the structure of a circuit board manufactured by the high current-carrying copper-embedded block circuit board manufacturing method of this utility model.
[0031] Figure 2 yes Figure 1 A schematic diagram of the structure of the optical board in the circuit board described above;
[0032] Figure 3 yes Figure 1 The diagram shown illustrates the connection between the bare board and the copper-embedded block in the circuit board.
[0033] Figure 4 yes Figure 3 The diagram shows the structure of the copper-embedded block. Detailed Implementation
[0034] To enable those skilled in the art to better understand the technical solutions in the embodiments of this utility model, and to make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be further described below.
[0035] It should be noted that the descriptions of these embodiments are for the purpose of aiding understanding of the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0036] A method for manufacturing a high current-carrying copper-embedded circuit board includes the following steps:
[0037] Step S1, Core board processing: Provide a first core board and a second core board, perform single-sided etching on the first core board and the second core board to create inner layer circuits, and drill rivet holes;
[0038] Specifically, the first core board includes first core board copper foil L1 and second core board copper foil L2, the second core board includes third core board copper foil L3 and fourth core board copper foil L4, the first core board copper foil L1 and fourth core board copper foil L4 are fully copper, and the second core board copper foil L2 and third core board copper foil L3 are etched to create inner layer circuits, the line width / spacing of the inner layer circuits is ≥100um;
[0039] The rivet hole diameter is 2.5mm-3.5mm, with a positional accuracy of ±20um.
[0040] Step S2, browning treatment;
[0041] Specifically, the micro-etching amount of the browning treatment is 0.8-1.2 μm, and the thickness of the browning film is 0.3-0.5 μm. The browning treatment can enhance the interlayer bonding force.
[0042] Step S3, fabricate a bare board and run out copper embedding grooves: provide a third core board, etch the third core board on both sides until the copper layer is completely removed to form a bare board, and then run out copper embedding grooves on the bare board. The size of the copper embedding grooves is equivalent to that of the copper embedding block.
[0043] In this embodiment, the thickness of the light board is 1.0mm, the thickness of the copper inlay block is 1.0mm±0.02mm, the depth of the copper inlay groove is 1.0mm±0.02mm (reserving space for pressurization and adhesive flow), and the size of the contact surface between the copper inlay groove and the copper inlay block is the size of the copper inlay block ±0.05mm (gap compensation).
[0044] Step S4, copper embedding block pretreatment: roughen the surface of the copper embedding block and apply a micro-adhesive film.
[0045] Specifically, the surface roughness of the copper-embedded block is Ra = 1.2-1.5 μm, and the micro-adhesive film is a polyimide film with a thickness of 50 μm and a temperature resistance of ≥200℃. The polyimide film is applied to the non-contact surface of the copper-embedded block.
[0046] Step S5: Embed the copper block into the light plate, then stack the first core plate, the light plate and the second core plate in sequence and fix them with rivets;
[0047] The rivets are stainless steel rivets with a diameter that matches the rivet hole.
[0048] Step S6, pressing: heating rate 2℃ / min, heating to 180℃, holding pressure 1.5MPa, holding time 90min;
[0049] Step S7: Mechanical drilling with a hole diameter of 3.0mm / 6.6mm. Carbide drill bits are used for drilling the copper block area, and the hole position accuracy is controlled within ±25um.
[0050] Step S8: Electroplating to make the copper thickness on the hole wall ≥30um and the copper thickness on the surface ≥72um;
[0051] Specifically, the process begins with chemical copper plating, achieving a copper layer thickness ≥0.4µm and a backlight level ≥9.5. Following this, pattern electroplating is performed using pulse electroplating. The electroplating process is as follows:
[0052] The concentrations of each component in the plating solution are as follows: Cu2 + 60~80g / L, H2SO4180~220g / L, Cl-40~80ppm;
[0053] The plating bath temperature is 20-30℃ to control ion mobility and deposition rate; and the plating bath is agitated with air or mechanically to reduce concentration variations.
[0054] When the through-hole has a low aspect ratio (i.e., thickness-to-diameter ratio ≤ 8:1), the current density is 2–4 A / dm. 2 The duty cycle is 20%-30%, the frequency is 100-300Hz, and the electroplating time is 60-90 minutes. When the through-hole has a high aspect ratio (i.e., thickness-to-diameter ratio > 8:1), such as in an HDI board, the current density is 4-6 A / dm. 2 The electroplating time is 90 min to 60 min.
[0055] Step S9: Double-sided depth control milling is performed to the surface of the copper block, and the milling depth is fed back in real time through laser ranging.
[0056] Specifically, double-sided milling uses a carbide milling cutter with a diameter of 1.8mm and a speed of 25,000rpm. For different copper block thicknesses (0.8-1.2mm), the feed rate is adjusted to 0.8-1.5m / min, and the single-sided milling depth is 1.0mm±0.1mm.
[0057] Then, through residual adhesive testing, the area of residual adhesive residue at the edge of the copper-embedded block was <0.01mm. 2 .
[0058] Step S10: Bend the copper-embedded block to complete the power circuit board fabrication;
[0059] The bent copper block is then annealed at a temperature of 150-170℃ for 30 minutes; the V-groove angle tolerance is ±0.5°, and the bending radius is 1.0mm ±0.05mm.
[0060] In this invention, the core board used is FR4 with a Tg ≥ 170℃; the copper inlay block is C1100 pure copper with a thickness of 1.0mm; the press is a vacuum hot press with a pressure accuracy of ±0.5kg / cm. 2 The milling machine is a CNC precision milling machine with an accuracy of ±0.05mm.
[0061] In this embodiment, the process parameter requirements and actual measurement parameters are as follows:
[0062] 1. Pressing thickness: 3.2mm, based on 10 sets of measured data, the thickness ranges from 3.16 to 3.26mm;
[0063] 2. The copper thickness of the hole wall is ≥30um, and the actual measured copper thickness of the hole wall is 32-35um. Ten copper slices were taken from the hole, and the range was 0.3um.
[0064] 3. Bending: 90°, actual measurement 89.8-90.6°.
[0065] The manufacturing method of the high current-carrying copper-embedded circuit board of this utility model, and the technical effects of the circuit board made by this invention are compared with those of circuit boards made by existing processes as follows:
[0066] index Traditional crafts This utility model Lamination thickness tolerance ±0.35 ±0.2mm Copper block alignment accuracy ±50um ±25um Residual adhesive defect rate 5％ ＜0.1％ Bending angle tolerance ±3° ±0.5° Current carrying capacity 30A (temperature rise 25℃) 50A (temperature rise < 15°C)
[0067] Please refer to the following: Figures 1 to 4 ,in Figure 1 This is a schematic diagram of the structure of a circuit board manufactured by the high current-carrying copper-embedded block circuit board manufacturing method of this utility model. Figure 2 yes Figure 1 A schematic diagram of the structure of the optical board in the circuit board described above; Figure 3 yes Figure 1 The diagram shown illustrates the connection between the bare board and the copper-embedded block in the circuit board. Figure 4 yes Figure 3 The diagram shows the structure of the copper-embedded block. The copper-embedded power circuit board of this embodiment includes a multilayer circuit board 1 formed by lamination, a through hole 2 formed through the multilayer circuit board 1, a first copper plating layer 3 deposited on the wall of the through hole 2, and a second copper plating layer 4 and a third copper plating layer 5 deposited on the surface of the outer copper foil of the multilayer circuit board 1, and outer circuitry is designed on the second copper plating layer 4 and the third copper plating layer 5.
[0068] The multilayer circuit board 1 includes a first core board 11, a bare board 12, and a second core board 13 stacked in sequence, and a copper inlay block 14 with one end embedded in the bare board 12 and the other end extending out of the bare board. The first core board 1, the bare board 2, and the second core board 3 are fixed by rivets and then pressed together.
[0069] The first core board 11 and the second core board 12 are FR4 core boards. Specifically, the first core board 11 includes an epoxy resin material layer 111, a first core board copper foil L1 and a second core board copper foil L2 stacked on both sides of the first epoxy resin material layer 111; the second core board 13 includes a second epoxy resin material layer 131, a third core board copper foil L3 and a fourth core board copper foil L4 stacked on both sides of the second epoxy resin material layer 131. The first core board copper foil L1 and the fourth core board copper foil L4 are entirely copper, while the second core board copper foil L2 and the third core board copper foil L3 are etched to create inner layer circuitry, with a linewidth / spacing of ≥100µm.
[0070] The first copper plating layer 3 is a hole wall copper layer with a thickness ≥30um; the second copper plating layer 4 is deposited on the surface of the first core board copper foil L1; and the third copper plating layer 5 is deposited on the surface of the fourth core board copper foil L4 with a thickness ≥72um.
[0071] The bare board 12 is formed by double-sided etching of the core board, and neither side of the bare board 12 contains copper foil. A copper embedding groove 121 is formed on the bare board 12. In this embodiment, the thickness of the copper embedding block 14 is 1.0mm ± 0.02mm, the groove depth of the copper embedding groove 121 is 1.0mm ± 0.02mm, the size of the contact surface between the copper embedding groove 121 and the copper embedding block 14 is equal to the size of the copper embedding block ± 0.05mm, and the position of the copper embedding block does not shift after it is embedded in the copper embedding groove.
[0072] Micro-adhesive film 141 is attached to the opposite sides of the copper embedding block 14. The micro-adhesive film 141 is a polyimide film with a thickness of 50 μm. The sides of the copper embedding block covered with the micro-adhesive film are the non-contact surfaces with the copper embedding groove, that is, the opposite sides in the thickness direction.
[0073] The copper inlay 14 extends beyond the bare plate and is bent to form a bent portion 142. The bending radius of the bent portion 142 is 1.0 mm ± 0.05 mm.
[0074] The copper-embedded power circuit board also includes a first heat dissipation hole 6 formed through the second copper plating layer 4 and the first core board 11, and a second heat dissipation hole 7 formed through the third copper plating layer 5 and the second core board, and the first heat dissipation hole 6 and the second heat dissipation hole 7 are distributed on two opposite sides of the copper-embedded block 14. There can be multiple first heat dissipation holes 6 and second heat dissipation holes.
[0075] The embodiments of this utility model have been described in detail above, but this utility model is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of this utility model still fall within the protection scope of this utility model.
Claims
1. A high current-carrying copper-embedded circuit board, characterized in that, The circuit includes a multilayer circuit board formed by lamination, a through hole formed through the multilayer circuit board, a first copper plating layer deposited on the wall of the through hole, and a second copper plating layer and a third copper plating layer deposited on the surface of the outer copper foil of the multilayer circuit board, wherein the second copper plating layer and the third copper plating layer are designed with outer circuits. The multilayer circuit board includes a first core board, a light board and a second core board stacked in sequence, and a copper block with one end embedded in the light board and the other end extending out of the light board. The first core board and the second core board are etched on one side to form the inner layer circuit. The first core board, the light board and the second core board are fixed by rivets and then pressed together. The high current-carrying copper-embedded block circuit board also includes a first heat dissipation hole formed through the second copper plating layer and the first core board, and a second heat dissipation hole formed through the third copper plating layer and the second core board. The first heat dissipation hole and the second heat dissipation hole are distributed on two opposite sides of the copper-embedded block.
2. The high current-carrying copper-embedded circuit board according to claim 1, characterized in that, The light board is formed by double-sided etching of the core board, and the copper layers on both sides of the light board are completely removed.
3. The high current-carrying copper-embedded circuit board according to claim 2, characterized in that, The light plate is provided with a copper embedding groove, and one end of the copper embedding block is embedded in the copper embedding groove.
4. The high current-carrying copper-embedded circuit board according to claim 3, characterized in that, The thickness of the light plate is 1.0 mm, the thickness of the copper inlay block is 1.0 mm ± 0.02 mm, and the size of the contact surface between the copper inlay groove and the copper inlay block is the size of the copper inlay block ± 0.05 mm.
5. The high current-carrying copper-embedded circuit board according to claim 1, characterized in that, The copper-embedded blocks are covered with micro-adhesive films on opposite sides. The micro-adhesive films are polyimide films with a thickness of 50 μm.
6. The high current-carrying copper-embedded circuit board according to claim 5, characterized in that, The end of the copper-embedded block extending outside the copper-embedded groove is bent to form a bent section, and the bending radius is 1.0mm±0.05mm.
7. The high current-carrying copper-embedded circuit board according to claim 1, characterized in that, The thickness of the first copper plating layer is ≥30µm, and the thicknesses of the second and third copper plating layers are ≥72µm.
8. The high current-carrying copper-embedded circuit board according to claim 1, characterized in that, There are multiple first and second heat dissipation holes.
9. The high current-carrying copper-embedded circuit board according to any one of claims 1-8, characterized in that, The first core board includes an epoxy resin material layer, a first core board copper foil and a second core board copper foil stacked on both sides of the first epoxy resin material layer. The second core board includes a second epoxy resin material layer, a third core board copper foil and a fourth core board copper foil stacked on both sides of the second epoxy resin material layer; In this process, the copper foils of the first and fourth core boards are all copper, while the copper foils of the second and third core boards are formed into inner layer circuits through etching.