A method for manufacturing a printed circuit board with embedded copper blocks and a printed circuit board

Abstract

The application provides a manufacturing method of a printed circuit board embedded with a copper block and the printed circuit board. The method comprises the following steps: obtaining a substrate of a circuit board and a copper block; performing slotting treatment on the substrate of the circuit board to obtain a substrate with a buried copper slot; performing etching treatment on the copper block to obtain a copper block with a circuit; obtaining a substrate with a copper block according to the substrate with the buried copper slot and the copper block with the circuit; and performing pressing treatment on the substrate with the copper block to obtain the printed circuit board embedded with the copper block. The manufacturing method can improve the bonding force between the copper block and the substrate and the qualification rate of the printed circuit board, effectively remove residual glue, and ensure the conductivity of the circuit.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing technology, and also to a method for manufacturing a printed circuit board with embedded copper blocks and the printed circuit board itself. Background Technology

[0002] Printed circuit boards (PCBs) are fundamental components of modern electronic devices, used to connect and support various electronic components. As electronic products become smaller, PCBs are also shrinking in size, with increasingly dense circuit designs. Due to the increased power density of components, excessive heat dissipation from PCBs can affect component lifespan, cause aging, and even component failure. Given the development of next-generation information technology, energy-saving and new energy vehicles, and power equipment, the heat dissipation problem of PCBs urgently needs to be solved. Directly embedding copper blocks within the PCB is one effective way to address this issue. However, existing manufacturing processes for PCBs with embedded copper blocks suffer from problems such as insufficient adhesion between the copper block and the substrate, poor heat resistance, difficulty in removing excess adhesive, and low product yield. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for manufacturing a printed circuit board with embedded copper blocks and a printed circuit board, so as to improve the bonding force between the copper blocks and the substrate and the product qualification rate.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] A first aspect of the present invention provides a method for manufacturing a printed circuit board with embedded copper blocks, comprising:

[0006] Obtain the circuit board substrate and copper block;

[0007] The substrate of the circuit board is slotted to obtain a substrate with buried copper trenches.

[0008] The copper block is etched to obtain a copper block with circuitry.

[0009] A substrate with a copper block is obtained based on a substrate with a copper trough and a copper block with circuitry.

[0010] The substrate with the copper block is laminated to obtain a printed circuit board with the copper block embedded in it.

[0011] Optionally, the substrate for obtaining the circuit board includes:

[0012] Obtain the inner core board and prepreg;

[0013] Based on the inner core board and the prepreg, a substrate with a stacked structure is obtained;

[0014] The substrate with the stacked structure is placed in a vacuum high-temperature press and pressed according to preset vacuum pressing parameters to obtain the pressed substrate.

[0015] The laminated substrate is pretreated to obtain the substrate for the circuit board.

[0016] Optionally, the laminated substrate undergoes substrate pretreatment to obtain the circuit board substrate, including:

[0017] The laminated substrate is immersed in 80% to 100% cleaning agent and cleaned for 20 to 30 minutes to obtain a substrate after one cleaning.

[0018] The substrate after the first cleaning is placed in a cleaning machine for water spraying treatment to obtain the substrate after the second cleaning.

[0019] The substrate after the second cleaning is dried to obtain the substrate of the circuit board.

[0020] Optionally, the substrate of the circuit board is slotted to obtain a substrate with buried copper trenches, including:

[0021] Obtain the preset slotting parameters;

[0022] According to the preset grooving parameters, the substrate of the circuit board is placed into the milling device for grooving to obtain a substrate with embedded copper grooves.

[0023] Optionally, the copper block is etched to obtain a copper block with circuitry, including:

[0024] The copper block is pretreated to obtain a pretreated copper block;

[0025] According to the preset circuit diagram, at least two sides of the copper block are etched to obtain a copper block with circuitry.

[0026] Optionally, the copper block is pretreated to obtain a pretreated copper block, including:

[0027] The copper block is flattened to obtain a flat copper block;

[0028] The flat copper block is immersed in a photoresist solution for copper block pretreatment to obtain a pretreated copper block.

[0029] Optionally, the substrate with the copper block is laminated to obtain a printed circuit board with the copper block embedded, including:

[0030] The substrate containing the copper block is subjected to a de-adhesive treatment to obtain a substrate after de-adhesive treatment;

[0031] The substrate after descaling is placed in a baking device for baking and shaping to obtain a baked substrate.

[0032] The baked substrate is cooled to obtain a cooled substrate.

[0033] The cooled substrate is placed into a riveting machine and pressed according to preset riveting parameters to obtain a printed circuit board with embedded copper blocks.

[0034] Alternatively, the manufacturing method of the printed circuit board with embedded copper blocks also includes:

[0035] The printed circuit board with embedded copper blocks is inspected according to preset inspection conditions to obtain a qualified printed circuit board with embedded copper blocks; the preset inspection conditions include at least one of the following conditions:

[0036] Baking conditions: Baking temperature between 121°C and 149°C, baking time of at least 6 hours;

[0037] The thermal stress test conditions are as follows: the thermal stress test temperature is 288℃±5℃, the thermal stress test time is at least 10s, and the thermal stress test is repeated at least 3 times.

[0038] In a second aspect, the present invention provides a printed circuit board with embedded copper blocks, wherein the printed circuit board with embedded copper blocks is prepared by the manufacturing method of the printed circuit board with embedded copper blocks described in any of the above claims.

[0039] The above-described solution of the present invention has at least the following beneficial effects:

[0040] The above-described solution of the present invention, by slotting the substrate and etching the copper block, and then pressing the substrate with the embedded copper groove with the copper block with the circuit, obtains a printed circuit board with embedded copper block. This not only improves the bonding force between the copper block and the substrate and the yield of the printed circuit board, but also effectively removes residual adhesive and ensures the conductivity of the circuit. Attached Figure Description

[0041] Figure 1 This is a flowchart illustrating the manufacturing method of a printed circuit board with embedded copper blocks according to an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the structure of a printed circuit board in which a copper block is embedded in a substrate, according to an embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram of the structure of a printed circuit board in which a copper block is embedded in a substrate, according to an embodiment of the present invention.

[0044] Figure 4 This is a schematic diagram of the circuit pattern on the copper block in an embodiment of the present invention;

[0045] Figure 5 yes Figure 4 Electrical schematic diagram of a circuit pattern.

[0046] Explanation of reference numerals in the attached diagram: 1-Copper conductor line, 2-Pad location, 3-Hole location. Detailed Implementation

[0047] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0048] like Figure 1 As shown, an embodiment of the present invention proposes a method for manufacturing a printed circuit board with embedded copper blocks, comprising the following steps:

[0049] Step 101: Obtain the substrate and copper block of the circuit board;

[0050] Step 102: Grooving is performed on the substrate of the circuit board to obtain a substrate with buried copper grooves.

[0051] Step 103: Etch the copper block to obtain a copper block with circuitry; Based on the substrate with embedded copper grooves and the copper block with circuitry, obtain a substrate with copper blocks.

[0052] Step 104: The substrate with copper blocks is laminated to obtain a printed circuit board with embedded copper blocks.

[0053] The method for manufacturing a printed circuit board with embedded copper blocks proposed in this invention involves slotting a substrate and etching a copper block, then pressing the substrate with embedded copper slots and the copper block with circuitry together to obtain a printed circuit board with embedded copper blocks. This method not only improves the bonding force between the copper block and the substrate and the yield rate of the printed circuit board, but also effectively removes residual adhesive and ensures the conductivity of the circuit.

[0054] In an optional embodiment of the present invention, step 101, obtaining the substrate of the circuit board, includes:

[0055] Step 1011: Obtain the inner core board and the prepreg;

[0056] Specifically, the substrate of a circuit board generally consists of an inner core board and a prepreg. Depending on the actual needs, a suitable material can be selected for the inner core board, such as FR4 (epoxy resin) or high-frequency hybrid materials. To improve the heat dissipation of the circuit board, the inner core board can also use high thermal conductivity substrate materials, such as aluminum substrates, copper substrates, metal composites, and ceramic substrates. The prepreg is made of polymer materials, mainly silicone rubber and hydrogenated silicone rubber, which have excellent high-temperature resistance and corrosion resistance, providing thermal insulation for the circuit board. Simultaneously, the prepreg has excellent expansion properties, which can fill the gaps between the circuit board and the heat sink, thereby increasing thermal conductivity. Current flowing through the circuit board generates heat. Poor heat dissipation can lead to an increase in circuit board temperature, potentially damaging the circuit board or even causing a fire. Therefore, using prepreg allows the heat sink to fit tightly against the circuit board, improving heat dissipation. Furthermore, the prepreg increases the contact area between different circuit board layers, reducing contact resistance and thus improving the conductivity and heat dissipation of multilayer circuit boards.

[0057] Step 1012: Based on the inner core board and the prepreg, a substrate with a stacked structure is obtained;

[0058] Specifically, multiple inner core boards and multiple prepregs can be stacked together in a predetermined order according to the preset requirements of the stacked structure, and then pressed together to form a substrate with a stacked structure.

[0059] Step 1013: Place the substrate with the stacked structure into a vacuum high-temperature press and press it according to the preset vacuum pressing parameters to obtain the pressed substrate.

[0060] Specifically, in order to fully cure the prepreg and increase the stability between the inner core boards, the temperature of each pressing must reach 175°C and be maintained for more than 70 minutes.

[0061] Step 1014: Perform substrate pretreatment on the laminated substrate to obtain the substrate of the circuit board.

[0062] In an optional embodiment of the present invention, step 1014 includes:

[0063] Step 10141: Immerse the laminated substrate in 80% to 100% cleaning agent and clean for 20 to 30 minutes to obtain a substrate after one cleaning.

[0064] Specifically, the cleaning agent can be an alkaline chemical (a cleaning agent with a pH value greater than 7), mainly used to remove oil, grease, and particulate matter from the substrate surface. Alkaline chemicals have the advantages of being environmentally friendly, non-toxic, safe, economical, and having good cleaning effects. Therefore, using alkaline chemicals to clean the laminated substrate can save costs and improve cleaning results. Specifically, the cleaning agent can be composed of 5% to 8% fatty alcohol polyoxyethylene ether (AEO-9), 8-10% coconut oil alkanolamide (6501), 2% to 4% triethanolamine oleate, 8% to 10% monoethanolamine, 0% to 1% benzotriazole, 1% to 2% disodium EDTA, and 70% to 75% water. An 80% to 100% alkaline chemical solution can be used to immerse and clean the laminated substrate within a temperature range of 60°C to 70°C.

[0065] Step 10142: Place the substrate after the first cleaning into a cleaning machine for water spraying treatment to obtain the substrate after the second cleaning.

[0066] Specifically, after cleaning the substrate, use a strong spray of clean water to remove the cleaning agent and ensure that there is no cleaning agent residue on the substrate. After alkaline soaking, rinse the cleaned substrate effectively with filtered oil-free tap water, soak it in water, and then spray it with strong water to ensure complete removal of the cleaning agent.

[0067] Step 10143: Dry the substrate after the secondary cleaning to obtain the substrate of the circuit board.

[0068] Specifically, the moisture on the substrate after the second cleaning is completely dried, which saves production time and facilitates subsequent production.

[0069] In an optional embodiment of the present invention, step 102 includes:

[0070] Step 1021: Obtain the preset slotting parameters;

[0071] Here, the preset grooving parameters are used to determine the position, distance, diameter, etc. of the grooving. Therefore, the preset grooving parameters can include the grooving diameter, grooving spacing, grooving depth, grooving shape, etc.

[0072] Step 1022: According to the preset grooving parameters, the substrate of the circuit board is placed into the milling device for grooving to obtain a substrate with embedded copper grooves.

[0073] Specifically, after determining the preset grooving parameters, the preset grooving parameters are input into the milling device, so that the milling device grooves the substrate of the circuit board according to the preset grooving parameters, so that the copper embedding groove on the substrate meets the design requirements, making it easier to place copper blocks in the copper embedding grooves later. In this embodiment, the copper embedding groove on the substrate is 0.05mm smaller on each side than the copper block size to improve the bonding force between the copper block and the substrate.

[0074] In an optional embodiment of the present invention, step 103 includes:

[0075] Step 1031: Perform copper block pretreatment on the copper block to obtain a pretreated copper block;

[0076] Step 1032: According to the preset circuit diagram, at least two sides of the copper block are etched to obtain a copper block with circuitry.

[0077] Specifically, in this embodiment, the copper block has a thickness of 0.4mm. Based on the line width / spacing of the circuit pattern, the copper block needs to be fabricated with both front and back circuits. First, the front circuit of the copper block is etched. After bonding the copper block to the substrate and using vacuum resin filling, the back of the copper block is then etched to create the required circuit pattern. The circuit pattern on the copper block must precisely overlap and connect with the circuit pattern on the substrate to form a conductive path.

[0078] In an optional embodiment of the present invention, step 1031 includes:

[0079] Step 10311: Flatten the copper block to obtain a flat copper block;

[0080] Specifically, in order to improve the bonding strength between the layers of the circuit board, the conductivity of the circuits, and the clarity of the subsequent circuits, it is necessary to ensure that the copper blocks are smooth and flat. Therefore, the copper blocks are first flattened to improve their flatness and smoothness.

[0081] Step 10312: Immerse the flat copper block in photoresist solution for copper block pretreatment to obtain pretreated copper block.

[0082] Specifically, a flat copper block is immersed in photoresist, ensuring each side is evenly coated. The photoresist protects the parts of the copper block that do not need etching during subsequent exposure. The photoresist-coated copper block is then placed in an exposure machine and exposed according to a pre-defined circuit diagram. After exposure, a developer is used to remove the photoresist that was not exposed to light, exposing the copper surface to be etched. The developed copper block is then immersed in an etching solution to etch away the parts not protected by the photoresist. After etching, the photoresist layer on the copper block is removed, exposing the complete etched circuit. Finally, the copper block is thoroughly cleaned to remove all residual etching solution and photoresist material, and the circuit on the copper block is inspected to ensure that the circuit is intact and free of defects.

[0083] In an optional embodiment of the present invention, step 104 includes:

[0084] Step 1041: The substrate with copper blocks is subjected to a desmearing process to obtain a substrate after desmearing.

[0085] Specifically, excess resin can be removed using a laser.

[0086] Step 1042: Place the substrate after descaling into a baking device for baking and shaping to obtain the baked substrate;

[0087] Specifically, the substrate after adhesive removal is placed in a baking device for baking and shaping, so that the resin can be cured and the position of the copper block can be stabilized.

[0088] Step 1043: Cool the baked substrate to obtain a cooled substrate;

[0089] To save time, a cooling compressor can be used to fill the baking device with cold air to achieve rapid cooling; or a nitrogen device can be used to inject nitrogen into the baking device to achieve rapid cooling.

[0090] Step 1044: The cooled substrate is placed into a riveting machine and pressed according to preset riveting parameters to obtain a printed circuit board with embedded copper blocks.

[0091] Specifically, the preset riveting parameters can be: a riveting temperature range of 175℃ to 190℃, and a riveting time of 70 minutes to 200 minutes. During the lamination process, resin may overflow from the gap between the copper block and the embedded copper groove. This overflow can be cleaned by drawing out the resin. During lamination, there is a certain height difference between the copper block and the substrate, which can easily lead to problems such as insufficient filling, voids, cracks, and delamination at the connection between the copper block and the substrate. Therefore, it is necessary to select a prepreg with an appropriate resin content. In addition, to ensure that the flatness of the copper block and the substrate is controlled within ±0.075 mm, it is necessary to match the required thickness of the copper block, the inner core board, and the prepreg. In a specific embodiment, the thickness of the circuit board substrate is 2 mm, the copper thickness is 1 / 1 / 1 / 1 oz, the minimum hole diameter on the circuit board substrate is 0.25 mm, and the thickness of the embedded / embedded copper block is 0.4 mm.

[0092] In an optional embodiment of the present invention, the method further includes the following steps:

[0093] Step 105: Inspect the printed circuit board with embedded copper blocks according to preset inspection conditions to obtain a qualified printed circuit board with embedded copper blocks; the preset inspection conditions include at least one of the following conditions:

[0094] Baking conditions: Baking temperature between 121°C and 149°C, baking time of at least 6 hours;

[0095] The thermal stress test conditions are as follows: the thermal stress test temperature is 288℃±5℃, the thermal stress test time is at least 10s, and the thermal stress test is repeated at least 3 times.

[0096] Here, to improve the pass rate of circuit boards and user satisfaction, it is necessary to inspect the printed circuit boards with embedded copper blocks. Only circuit boards that pass the preset inspection conditions are qualified printed circuit boards with embedded copper blocks and can be used for subsequent manufacturing or shipment. In this embodiment, after the printed circuit boards with embedded copper blocks are inspected according to the above inspection method, qualified printed circuit boards with embedded copper blocks have the advantages of no voids, cracks, delamination, etc. in the gap between the copper blocks and the board, and good heat resistance.

[0097] like Figure 2 and Figure 3 As shown, an embodiment of the present invention provides a printed circuit board with embedded copper blocks. The printed circuit board with embedded copper blocks is manufactured using the method described in any one of the above embodiments. Specifically, the printed circuit board includes a substrate with embedded copper grooves, and copper blocks with circuit patterns are pressed into the embedded copper grooves. This printed circuit board with embedded copper blocks has the advantages of no voids, cracks, or delamination between the copper blocks and the board, and good heat resistance.

[0098] Figure 2 The diagram shows the structure of a printed circuit board with copper blocks embedded in a substrate. Multiple inner core boards 1 and multiple prepregs 2 are stacked together according to preset requirements to form the substrate of the circuit board. Figure 1 As shown, copper block 3 is embedded in the substrate.

[0099] Figure 3 Copper blocks are embedded in the substrate, and multiple inner core boards 1 and multiple prepreg sheets 2 are stacked together according to preset requirements to form the substrate of the circuit board. Figure 1 As shown, copper block 3 is embedded in the substrate.

[0100] It should be noted that, Figure 2 and Figure 3 This is merely an illustrative representation of the structure of a printed circuit board with embedded copper blocks and is not intended to limit the scope of protection of this invention.

[0101] like Figure 4 The diagram shows a specific embodiment of a circuit pattern on a copper block. In this embodiment of the invention, the circuit pattern is used to create a laser alarm. Figure 4 In the process, the etched circuitry on the copper block includes copper conductor line 1, pad position 2, and hole position 3, which are used to install copper conductors, pads, and holes, respectively. Figure 4 Electrical schematic diagram of circuit pattern as follows Figure 5 As shown, the main power supply is a 3V DC battery. When laser light shines on the photoresistor, its resistance decreases, the voltage drop across the potentiometer exceeds 0.7V, the base voltage of the PNP transistor is greater than 0.7V, the transistor does not conduct, the buzzer does not sound, and the LED does not light up. When someone blocks the laser light shining on the photoresistor, its resistance increases, the voltage drop across the potentiometer is less than 0.7V, the base voltage of the PNP transistor is less than 0.7V, the transistor conducts, the buzzer is connected to the battery, the buzzer sounds, and the LED lights up. This alarm is installed at the corners of both sides of the corridor. The spacing between each pair of buzzers and LED lights is 1 meter, for a total of 100 pairs, with a total installation length of 100 meters. It is usually installed bidirectionally, allowing monitoring at both ends of the corridor.

[0102] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for manufacturing a printed circuit board embedded with a copper block, characterized by, The method comprises the following steps: obtaining a substrate of a circuit board and a copper block; slotting the substrate of the circuit board to obtain a substrate with a buried copper slot; etching the copper block to obtain a copper block with circuits; obtaining a substrate with a copper block according to the substrate with the buried copper slot and the copper block with circuits; specifically, the method comprises the following steps: performing copper block pretreatment on the copper block to obtain a pretreated copper block; etching at least two surfaces of the copper block according to a preset circuit diagram to obtain the copper block with circuits; specifically, the thickness of the copper block is 0.4 mm, the copper block is processed to form front and back circuits according to the line width / line spacing of the circuit pattern, the front circuit of the copper block is etched first, the copper block is pressed against the substrate, and then the back circuit of the copper block is etched to form the required circuit pattern on the copper block; wherein the copper block pretreatment comprises the following steps: performing flattening treatment on the copper block to obtain a flattened copper block; immersing the flattened copper block in a photoresist liquid for copper block pretreatment to obtain a pretreated copper block; wherein the flattened copper block is immersed in the photoresist liquid, and each surface of the copper block is uniformly coated with the photoresist liquid; the copper block coated with the photoresist liquid is placed in an exposure machine, and exposure is performed according to a preset circuit diagram; after exposure, the photoresist liquid that is not exposed to light is removed using a developing liquid to expose the surface of the copper block that needs to be etched; the copper block after developing is placed in an etching liquid, and the part of the copper block that is not protected by the photoresist liquid is etched away; after etching, the photoresist layer on the copper block is removed to expose the complete etching circuit; the copper block is cleaned; performing pressing treatment on the substrate with the copper block to obtain a printed circuit board with the copper block embedded therein; specifically, the substrate with the copper block is subjected to glue removal treatment to obtain a substrate after glue removal; the substrate after glue removal is placed in a baking device for baking and shaping treatment to obtain a baked substrate; the baked substrate is subjected to cooling treatment to obtain a cooled substrate; the cooled substrate is placed in a riveting machine and subjected to pressing treatment according to preset riveting parameters to obtain a printed circuit board with the copper block embedded therein; the preset riveting parameters include a riveting temperature range of 175-190°C and a riveting time of 70-200 minutes; wherein the substrate of the circuit board is obtained by the following steps: obtaining an inner layer core board and a prepreg; obtaining a substrate with a stacking structure according to the inner layer core board and the prepreg; placing the substrate with the stacking structure in a vacuum high-temperature press and pressing according to preset vacuum pressing parameters to obtain a pressed substrate; the temperature of each pressing reaches 175°C and is maintained for more than 70 minutes; performing substrate pretreatment on the pressed substrate to obtain the substrate of the circuit board; wherein the substrate pretreatment on the pressed substrate to obtain the substrate of the circuit board comprises the following steps: The pressed substrate is immersed in 80% to 100% cleaning agent for 20 to 30 minutes to obtain a first cleaned substrate; the cleaning agent is composed of 5% to 8% fatty alcohol polyoxyethylene ether, 8% to 10% coconut oil alkanolamide, 2% to 4% triethanolamine oleate, 8% to 10% monoethanolamine, 0% to 1% benzotriazole, 1% to 2% disodium EDTA, and 70% to 75% water; The first cleaned substrate is placed in a cleaning machine for water jet treatment to obtain a second cleaned substrate; The second cleaned substrate is subjected to drying treatment to obtain a circuit board substrate; The circuit board substrate is subjected to slotting treatment to obtain a substrate with a buried copper slot, including: Obtaining preset slotting parameters; the preset slotting parameters include slotting diameter, slotting spacing, slotting depth, and slotting shape; According to the preset slotting parameters, the circuit board substrate is placed in a slot milling device for slotting treatment to obtain a substrate with a buried copper slot; wherein the preset slotting parameters are input into the slot milling device, so that the slot milling device performs slotting treatment on the circuit board substrate according to the preset slotting parameters; The method further includes: According to a preset inspection condition, the printed circuit board with the embedded copper block is inspected to obtain a qualified printed circuit board with the embedded copper block; the preset inspection condition includes at least one of the following conditions: Baking condition, baking temperature is 121°C to 149°C, and baking time is at least 6 hours; Thermal stress test condition, thermal stress test temperature is 288°C±5°C, thermal stress test time is at least 10s, and thermal stress test time number is at least 3 times.

2. A printed circuit board with embedded copper blocks, characterized in that The printed circuit board with the embedded copper block is prepared by the method for manufacturing the printed circuit board with the embedded copper block according to claim 1.

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