A multilayer printed circuit board and its integrated manufacturing method

Abstract

This invention discloses a multilayer printed circuit board and its integrated manufacturing method, belonging to the field of PCB manufacturing technology. Specifically, it includes the following steps: printing a ceramic insulating substrate blank for the multilayer printed circuit board, reserving conductive line channels; degreasing and sintering the printed ceramic insulating substrate blank to obtain a multilayer printed circuit board ceramic insulating substrate; processing a fixed mold and a moving mold for the multilayer printed circuit board, applying a release agent to the fixed mold and the moving mold, and then assembling them with the ceramic insulating substrate; die-casting conductive material into the reserved conductive line channels; and opening the mold after the conductive material has cooled and solidified for post-processing. This manufacturing method combines ceramic additive manufacturing technology and metal die-casting technology, enabling the integrated manufacturing of multilayer printed circuit boards. Compared with traditional manufacturing methods, the process is simpler and the manufacturing cycle is shorter. It also solves problems such as misalignment, displacement, and poor positioning and dimensional accuracy of the copper base caused by multilayer pressing in traditional processes.

Description

Technical Field

[0001] This invention belongs to the field of PCB manufacturing technology, specifically relating to a multilayer printed circuit board and its integrated manufacturing method. Background Technology

[0002] Printed circuit boards (PCBs) are important electronic components, serving as the carriers that support electronic components and enable electrical interconnection. Multilayer printed circuit boards refer to circuit boards made of three or more conductive copper layers. They are typically formed by stacking alternating insulating layers and prefabricated conductive inner substrates to create multilayer semi-finished products, which are then processed through processes such as pressing and surface etching to finally obtain the multilayer printed circuit board.

[0003] Manufacturing multilayer printed circuit boards (PCBs) using traditional processes is complex, and misalignment and displacement are prone to occur during continuous pressing, severely affecting the precision and reliability of the PCBs. Furthermore, the positioning accuracy, dimensional accuracy, and pressing of the copper substrate during copper conductor filling are critical aspects of product quality control; poor control of any of these indicators increases the risk of PCB failure. Additionally, the bonding strength between the copper layer and the substrate is often weak, making it susceptible to detachment.

[0004] To address the misalignment and displacement issues caused by continuous pressing processes, CN 118660400 A, "Continuous Pressing Manufacturing Process for Multilayer PCBs," employs a PIN pin positioning system and a rivet positioning system located on the PCB edge to align and fix the stacked structure before final pressing, thereby improving the overall alignment and accuracy of the stacked structure. To improve the positioning accuracy of the copper base, CN118368832 A, "A Manufacturing Process for Embedded Copper in Multilayer PCBs," pre-mills the copper into shape, mills copper embedding grooves into the insulating substrate, embeds the copper block into the grooves, and seals it with resin to solve the problem of accurate copper block embedding. While these existing technologies can improve the manufacturing precision of multilayer printed circuit boards to some extent, their manufacturing processes still involve multilayer pressing, and even add multiple milling and embedding steps on top of the multilayer pressing process, undoubtedly increasing assembly errors, and overall manufacturing precision still cannot be guaranteed.

[0005] To improve the adhesion between the substrate and copper, CN 117956689 A, "A PCB board manufacturing method for preventing hole wall separation," controls the roughness during drilling and milling grooves on the multilayer circuit board, followed by drying, copper plating, and secondary drying to enhance the adhesion between the substrate and copper. This process is particularly complex, and ensuring precision is difficult. CN 114302562 B, "A PCB board manufacturing method for preventing hole wall separation," increases the contact area between the copper and the milled groove wall by designing coarsened holes along the edge of the milled groove, thereby improving the interfacial adhesion. However, the final surface will exhibit noticeable unevenness. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, such as large assembly errors, inability to guarantee overall manufacturing precision, and poor bonding ability between conductive metal and substrate, the present invention aims to provide an additive manufacturing method for multilayer printed circuit boards. This method combines ceramic additive manufacturing technology and metal die casting technology, which can realize the integrated manufacturing of multilayer PCB boards.

[0007] To achieve the above objectives, the present invention employs the following technical solution: The first objective of this invention is to provide an integrated manufacturing method for multilayer printed circuit boards (hereinafter referred to as multilayer PCBs), comprising the following steps: Print the ceramic insulating substrate blank for multilayer PCB board, and reserve conductive line channels; The printed ceramic insulating substrate blank is degreased and sintered to produce a ceramic insulating substrate for a multilayer PCB board; The fixed mold and moving mold of the multilayer PCB are processed, and after applying a release agent to the fixed mold and moving mold, they are assembled with the ceramic insulating substrate; Conductive material is die-cast and filled into the reserved conductive circuit channels; After the conductive material cools and solidifies, the mold is opened and post-processing is carried out.

[0008] Preferably, the printing of the ceramic insulating substrate blank specifically involves using ceramic slurry or ceramic powder as the printing material and employing photopolymerization printing or selective laser sintering to print the ceramic insulating substrate blank.

[0009] Preferably, in the process of degreasing and sintering the printed ceramic insulating substrate blank to produce a multilayer PCB board ceramic insulating substrate, the ceramic insulating substrate blank is subjected to isostatic pressing treatment before the degreasing and sintering.

[0010] Preferably, in the process of degreasing and sintering the printed ceramic insulating substrate blank to obtain the ceramic insulating substrate for the multilayer PCB board, the degreasing process specifically includes: The degreasing temperature is set to 800℃~900℃, and the heating process is a stepped heating mode. Before reaching the set degreasing temperature, the heating rate is no less than 5℃ / min. When approaching the degreasing temperature, the heating rate is reduced to no more than 2℃ / min. After reaching the set degreasing temperature, the holding time is 2h~4h.

[0011] Preferably, in the process of degreasing and sintering the printed ceramic insulating substrate blank to obtain the ceramic insulating substrate for the multilayer PCB board, the sintering process specifically includes: After decarburizing the degreased ceramic insulating substrate, it is sintered under a protective atmosphere. The maximum sintering temperature range during the sintering process is 1600℃~2000℃, and the holding time is 2h~4h.

[0012] Preferably, the ceramic insulating substrate of the multilayer PCB is made of silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, or zirconium oxide.

[0013] Preferably, the moving mold includes a moving mold sleeve plate, with a through hole in the center of the moving mold sleeve plate for placing the ceramic insulating substrate. The moving mold sleeve plate is set on a moving mold pressure plate, with a through hole in the center of the moving mold pressure plate for installing a moving mold insert. The fixed mold is installed on the upper surface of the moving mold, and a support plate is provided on the lower surface of the moving mold. The push rod passes through the support plate and the moving mold insert and abuts against the lower surface of the ceramic insulating substrate.

[0014] Preferably, the step of die-casting and filling the reserved conductive line channel with conductive material specifically involves using a cold chamber die-casting process to fill the reserved conductive line channel in the ceramic insulating substrate with conductive material.

[0015] Preferably, the conductive material is a metallic dielectric material.

[0016] Preferably, the die-casting pressure of the cold chamber die-casting is 15~100MPa.

[0017] A second objective of this invention is to provide a multilayer PCB board produced by the integrated manufacturing method of the aforementioned multilayer PCB board.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention combines ceramic additive manufacturing technology with metal die casting technology to achieve integrated manufacturing of multilayer PCBs. Compared with traditional manufacturing methods, the process is simpler and the manufacturing cycle is shorter. It avoids problems such as misalignment, displacement, and poor positioning and dimensional accuracy of the copper base caused by multilayer pressing in traditional processes. The printed ceramic part directly serves as a mold, and the copper conductor is subsequently filled using the metal die casting process to achieve a high-precision bond between the ceramic part and the copper layer. Ceramic additive manufacturing technology enables integrated printing of the ceramic part of complex multilayer PCBs, allowing for a high degree of freedom in the structural design of the circuit board. The use of metal die casting for copper conductor filling can improve the bonding strength between the ceramic matrix and the copper. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a die-casting mold for a multilayer PCB board. Figure 2 The process flow of this invention is as follows; Among them, the fixed mold 1, the sprue bushing 2, the spring ejector pin 3, the moving mold 4, the moving mold sleeve plate 41, the moving mold pressure plate 42, the moving mold insert 43, the support plate 5, the ceramic insulating substrate 6, the push rod 7, and the copper conductor 8. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] The present invention will now be described in further detail with reference to the accompanying drawings: like Figure 2 The diagram shows the process steps used in an embodiment of the present invention, specifically including the following steps: Print the ceramic insulating substrate blank for multilayer PCB board, and reserve conductive line channels; The printed ceramic insulating substrate blank is degreased and sintered to produce a ceramic insulating substrate 6 for a multilayer PCB board; After grinding and polishing the fixed mold 1 and moving mold 4 of the multilayer PCB board, a release agent is applied to the fixed mold 1 and moving mold 4 before assembly with the ceramic insulating substrate 6. Conductive material is die-cast and filled into the conductive circuit channel reserved in the ceramic insulating substrate 6; After the conductive material cools and solidifies, the mold is opened, and the ceramic insulating substrate 6 is subjected to post-processing such as deburring, polishing, solder resisting, and text transfer.

[0023] In this embodiment of the invention, additive manufacturing technology is used to prepare multilayer PCB substrates. Compared with traditional manufacturing technologies, its most significant advantage lies in its ability to manufacture complex structures that are difficult or even impossible to achieve using traditional processes. Traditional manufacturing processes often require the assembly of multiple parts to obtain the final product. However, additive manufacturing does not impose many restrictions on the product's structure, enabling integrated design and one-piece manufacturing of the target product. This significantly shortens the manufacturing cycle, reduces the accumulation of errors caused by multiple assembly steps, and thus improves the product's manufacturing precision.

[0024] Preferably, in some embodiments of the present invention, the process for printing the ceramic insulating substrate 6 is a photopolymerization printing process or a selective laser sintering process.

[0025] The material used to print the ceramic insulating substrate blank is ceramic slurry or ceramic powder.

[0026] Photopolymerization printing technology can precisely construct complex three-dimensional structures during the layer-by-layer curing process. It can manufacture ceramic insulating components with fine internal channels, thin-walled structures, and complex curved surfaces, meeting the application scenarios with extremely high structural design requirements. For example, in microelectronic devices, it can provide customized high-precision insulation protection structures for chips, ensuring the stability of electronic signal transmission and reducing signal interference. During the photopolymerization printing process, because the curing process is relatively mild, it can reduce the formation of internal defects in ceramic materials during the forming process, such as cracks and pores, making it particularly suitable for insulation applications.

[0027] Selective laser sintering (SLS) uses a laser to selectively sinter ceramic powder, achieving complex shapes without the need for molds. It is particularly suitable for manufacturing ceramic insulators with irregular shapes or unique topologies, meeting specific spatial and functional requirements, and improving the overall performance and reliability of equipment. SLS can also control the microstructure of ceramics to a certain extent. By adjusting the laser parameters, the grain size and crystal orientation after sintering can be changed, which helps to optimize the insulation resistance of the ceramic matrix and reduce electrical properties such as dielectric loss, thereby improving the efficiency of power transmission and conversion and reducing energy loss.

[0028] In an embodiment of the present invention, the fixed mold 1 and the moving mold 4 of the multilayer PCB board are made of hot-rolled die steel. Hot-rolled die steel has high strength and toughness, can withstand greater pressure, impact and friction, and can maintain good dimensional stability at high temperatures, ensuring processing accuracy.

[0029] In some embodiments of the present invention, in the step of degreasing and sintering the printed ceramic insulating substrate blank to obtain a multilayer PCB ceramic insulating substrate 6, the ceramic insulating substrate blank is subjected to isostatic pressing treatment before degreasing and sintering.

[0030] After ceramic powder is printed, the green body typically contains a certain amount of porosity. Isostatic pressing (IPP) applies uniform high pressure to the green body, causing powder particles to shift and rearrange under the same pressure in all directions. This effectively reduces the number and size of pores. The uniform pressure of IPP ensures that the density of each part of the green body is consistent, eliminating stress concentration caused by localized density inconsistencies. IPP also promotes closer contact between ceramic powder particles, increasing interparticle friction and bonding. During subsequent sintering, this tight particle bonding facilitates diffusion and reaction, promoting the growth and densification of ceramic crystals, further improving the overall properties of the ceramic, such as electrical insulation and thermal stability, enabling it to better meet the high-performance requirements of practical applications.

[0031] In an embodiment of the present invention, the degreasing process is specifically as follows: the degreasing temperature is set to 800℃~900℃, the heating process is a stepped heating mode, the heating rate is controlled above 5℃ / min before reaching the set degreasing temperature, the heating rate is reduced to below 2℃ / min when approaching the degreasing temperature, and the holding time after reaching the set degreasing temperature is 2h~4h.

[0032] In an embodiment of the present invention, the sintering process specifically involves: decarburizing the degreased ceramic insulating substrate and then sintering it under a protective atmosphere. The maximum sintering temperature during the sintering process ranges from 1600℃ to 2000℃, and the holding time is from 2h to 4h.

[0033] In embodiments of the present invention, depending on the selected printing material, after degreasing and sintering, the ceramic insulating substrate 6 of the circuit board can be made of silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, or zirconium oxide.

[0034] In these embodiments, the moving mold 4 specifically includes a moving mold sleeve 41, a moving mold pressure plate 42, a moving mold insert 43, etc. Figure 1 As shown, after grinding and polishing each part of the mold, a release agent is applied. The ceramic insulating substrate 6, moving mold 1, and moving mold 4 are then assembled. The specific assembly method is as follows: The bottom layer is a support plate 5. A moving mold plate 42 is placed on the upper surface of the support plate 5. A moving mold insert 43 is embedded in the central area of ​​the moving mold plate 42. The support plate 5 and the moving mold insert 43 have pre-reserved channels for aligned push rods 7. The ceramic insulating substrate 6 is placed in the center of the moving mold sleeve plate 41 and is located on the plane formed by the moving mold insert 43 and the moving mold plate 42. The ceramic insulating substrate 6 has the same thickness as the moving mold sleeve plate 41. A fixed mold 1 is set on the upper part of the fixed mold 1. The fixed mold 1 is provided with multiple spring pins 3 for fixing the fixed mold 1 to the moving mold sleeve plate 41. The fixed mold 1 is also provided with a funnel-shaped sprue sleeve 2, which is used to fill the reserved wire channels of the ceramic insulating substrate 6 with conductors.

[0035] In an embodiment of the present invention, a cold chamber die casting process is used to fill the conductive circuit channels reserved in the ceramic insulating substrate with conductive material.

[0036] Cold chamber die casting allows for the application of high pressure during the die casting process, enabling molten metal to quickly and evenly fill all the intricate parts within the mold cavity. For castings with fine structures, such as thin walls, deep holes, and fine threads, high pressure ensures that the molten metal overcomes its own viscosity and surface tension, completely replicating the shape of the mold cavity, thus obtaining a clear and accurate outline of the fine structure. Furthermore, cold chamber die casting offers flexibility in mold material and design requirements, adapting to a variety of mold materials. The process parameters of cold chamber die casting are also easy to precisely control. By accurately controlling these parameters, the molten metal can achieve a reasonable flow and solidification sequence in different parts, avoiding defects such as porosity and shrinkage cavities, improving the internal quality of the casting, and ensuring structural integrity and functionality.

[0037] In the embodiments of the present invention, the die-casting pressure of cold chamber die casting is 15~100MPa, and the selected conductive material is a metallic dielectric material.

[0038] The following is a detailed description with reference to specific embodiments: Example 1 In this embodiment, the integrated manufacturing process of the multilayer PCB board specifically includes the following steps: S1, based on the pre-designed multilayer PCB board, using silicon nitride ceramic powder as the printing raw material, selective laser sintering is used to print the ceramic insulating substrate blank of the multilayer PCB board, reserving channels for conductive lines to fill copper conductors 8, such as... Figure 1 As shown, the silicon nitride powder used is prepared by mixing granulated silicon nitride powder (D50=30~70μm) and epoxy resin (EP12) at a mass fraction of 85% and 15%, respectively.

[0039] S2. After drying the ceramic insulating substrate blank printed in S1, it is first subjected to isostatic pressing, and then placed in a high-temperature furnace for degreasing and sintering to produce a multilayer PCB ceramic insulating substrate 6.

[0040] Isostatic pressure process: The first pressure is 160MPa (30s), the second pressure is 80MPa (10s), the pressure is set to rise to the predetermined pressure in 3 minutes, the pressure is maintained and then released, and the unloading is completed from the second pressure in 5 minutes.

[0041] Degreasing process: The billet is placed in a degreasing furnace for degreasing. The degreasing temperature is 800℃ and the holding time is 2h~4h. A gradient heating mode is selected. Before reaching the degreasing temperature, the heating rate is controlled above 5℃ / min. When approaching the degreasing temperature, the heating rate is reduced to below 2℃ / min.

[0042] Sintering process: First, the degreased green blank is decarburized in air using a fluctuating decarburization process. The temperature is increased to 300℃ at 1℃ / min and held for 1~2h for low-temperature decarburization. Then, the temperature is reduced to room temperature at 2℃ / min. Next, the temperature is increased to 500℃ at 1℃ / min and held for 1~2h for high-temperature decarburization. Then, the blank is cooled with the furnace. Subsequently, sintering is carried out under nitrogen (3MPa) conditions, with a maximum temperature of 1750℃ and a holding time of 2h.

[0043] S3 uses hot-rolled die steel powder as raw material to print the fixed mold 1 and moving mold 4 of a multilayer PCB board through selective laser melting. After post-processing such as grinding and polishing, a release agent is applied to the fixed mold 1 and moving mold 4, and then they are assembled with the ceramic insulating substrate 6. The assembled structure is as follows. Figure 1 As shown.

[0044] S4 uses a cold chamber die-casting machine to fill the reserved conductive line channel of the ceramic insulating substrate 6 with copper conductor 8 under a pressure of 100MPa; the die-casting machine model is LR-C160T, the maximum clamping force is 1600kN, and the casting speed is 10~15s / mold.

[0045] S5. After the copper conductor 8 cools and solidifies, the mold is opened, and the ceramic insulating substrate 6 is deburred, polished, solder resisted, and text transferred, etc., to obtain the required multilayer PCB circuit board.

[0046] Example 2 In this embodiment, the integrated manufacturing process of the multilayer PCB board specifically includes the following steps: S1. Based on a pre-designed multilayer PCB board, using aluminum nitride ceramic slurry as the printing raw material, a photopolymerization printing process is employed to print the ceramic insulating substrate blank of the multilayer PCB board, reserving channels for conductive lines. The aluminum nitride ceramic slurry used is an aluminum nitride slurry with a volume solid content of 40%, prepared by adding aluminum nitride solid powder to a premixed liquid in a certain proportion. Aluminum nitride ceramic and sintering aid powder are mixed to obtain solid powder. The particle sizes of the aluminum nitride ceramic powder are 10μm, 2μm, and 500nm, with a mass ratio of 5:3:2. The sintering aid is Y2O3 (0.5μm particle size), which accounts for 5% of the total mass of the solid powder. The photosensitive resin premixed liquid consists of photopolymer PUA and monomer ACMO in a mass ratio of 3:2. High refractive index resin BPEF is also introduced, accounting for 5% of the prepolymer mass. Finally, 3% of the total resin mass of photoinitiator TPO is added and thoroughly mixed and dissolved.

[0047] S2. After drying the ceramic insulating substrate blank printed in S1, it is placed in a high-temperature furnace for degreasing and sintering to produce a multilayer PCB ceramic insulating substrate 6.

[0048] Degreasing process: The blank is placed in a degreasing furnace for degreasing at a temperature of 890℃. Degreasing is carried out using a gradient heating method. First, the temperature is increased to 200℃ at a rate of 5℃ / min, then increased to 300℃ at a rate of 1℃ / min and held for 2 hours. Next, the temperature is increased to 600℃ at a rate of 0.5℃ / min and held for 2 hours. Finally, the temperature is increased to 890℃ at a rate of 1℃ / min and held for 1 hour.

[0049] Sintering process: sintering temperature is 1850℃, pressure is 0.8MPa, and holding time is 4h.

[0050] S3 uses hot-rolled die steel as raw material. After the moving mold 4 and fixed mold 1 are prepared by electron beam melting process, they are ground, polished and other post-processing. A release agent is applied to the moving mold 4 and fixed mold 1 and assembled with the ceramic insulating substrate 6 after sintering in S2.

[0051] S4 uses a cold chamber die-casting machine to fill the pre-reserved conductive line channel of the ceramic insulating substrate 6 with copper conductors 8 under a pressure of 60MPa. The die-casting machine model is LR-C100T, the maximum clamping force is 70kN, and the casting speed is 10~15s / mold.

[0052] S5. After the copper conductor 8 cools and solidifies, the mold is opened, and the ceramic insulating substrate 6 is deburred, polished, solder resisted, and text transferred, etc., to obtain the required multilayer PCB circuit board.

[0053] Example 3 In this embodiment, the integrated manufacturing process of the multilayer PCB board specifically includes the following steps: S1, based on a pre-designed multilayer PCB board, a ceramic insulating substrate blank for the multilayer PCB board is printed using silicon carbide ceramic slurry as the printing raw material and a photopolymerization printing process, reserving channels for conductive lines. The silicon carbide ceramic slurry used is a silicon carbide slurry with a volume solid content of 40%, which is prepared by adding silicon carbide solid powder to a premixed liquid in a certain proportion. The silicon carbide ceramic and sintering aid powder are mixed to obtain a solid powder. The particle size of the silicon carbide ceramic powder is 3μm, and the sintering aid is Y2O3 (particle size 0.5μm), which accounts for 5% of the total mass of the solid powder. The photosensitive resin premixed liquid is composed of photopolymer PUA and monomer ACMO in a mass ratio of 3:2. At the same time, high refractive index resin DPHA is introduced, which accounts for 5% of the prepolymer mass. Then, 3% of the total resin mass of photoinitiator TPO is added and thoroughly mixed and dissolved to obtain the final product. S2, after degreasing and drying the ceramic insulating substrate blank printed in S1, it is placed in a high-temperature furnace for degreasing and sintering to produce a multilayer PCB ceramic insulating substrate 6.

[0054] Degreasing process: The billet is placed in a degreasing furnace for degreasing. The degreasing temperature is 800℃ and the holding time is 2h~4h. A gradient heating mode is selected. Before reaching the degreasing temperature, the heating rate is controlled above 5℃ / min. When approaching the degreasing temperature, the heating rate is reduced to below 2℃ / min.

[0055] Sintering process: First, the degreased green blank is decarburized in air using a fluctuating decarburization process. The temperature is increased to 300℃ at a rate of 1℃ / min and held for 1-2 hours for low-temperature decarburization. Then, the temperature is reduced to room temperature at a rate of 2℃ / min. Next, the temperature is increased to 500℃ at a rate of 1℃ / min and held for 1-2 hours for high-temperature decarburization, followed by furnace cooling. Sintering is carried out under nitrogen (3MPa) conditions, with a maximum temperature of 1900℃ and a holding time of 2 hours.

[0056] S3 uses hot-rolled die steel as raw material to prepare moving mold 4 and fixed mold 1 through machining. After completion, grinding and polishing are carried out, and release agent is applied to moving mold 4 and fixed mold 1. They are then assembled with ceramic insulating substrate 6 sintered by S2.

[0057] S4 uses a cold chamber die-casting machine to fill the pre-reserved conductive line channel of the ceramic insulating substrate 6 with copper conductors 8 under a pressure of 15MPa; the die-casting machine model is LR-C50T, the maximum clamping force is 50kN, and the casting speed is 10~15s / mold.

[0058] S5. After the copper conductor 8 cools and solidifies, the mold is opened, and the ceramic substrate 6 is deburred, polished, solder resisted, and text transferred to obtain the required multilayer PCB circuit board.

[0059] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An integrated manufacturing method for a multilayer printed circuit board, characterized in that, Includes the following steps: A ceramic insulating substrate blank for printing multilayer printed circuit boards is provided with a reserved conductive line channel. Specifically, the ceramic insulating substrate blank is printed by using ceramic slurry or ceramic powder as the printing material and employing photopolymerization printing or selective laser sintering to print the ceramic insulating substrate blank. The printed ceramic insulating substrate preform is degreased and sintered to produce a ceramic insulating substrate for a multilayer printed circuit board. The degreasing process specifically involves setting the degreasing temperature to 800℃~900℃, using a stepped heating mode, with a heating rate of no less than 5℃ / min before reaching the set degreasing temperature, decreasing the heating rate to no more than 2℃ / min as the temperature approaches the degreasing temperature, and holding the preform at the set degreasing temperature for 2h~4h. The sintering process specifically involves removing carbon from the degreased ceramic insulating substrate preform and sintering it under a protective atmosphere, with a maximum sintering temperature range of 1600℃~2000℃ and a holding time of 2h~4h. Before degreasing and sintering, the ceramic insulating substrate preform undergoes isostatic pressing treatment. The fixed mold and moving mold of the multilayer printed circuit board are processed. After the fixed mold and moving mold are coated with a release agent, they are assembled with the ceramic insulating substrate. The moving mold (4) includes a moving mold sleeve plate (41). The moving mold sleeve plate (41) has a through hole in the center for placing the ceramic insulating substrate. The moving mold sleeve plate (41) is set on the moving mold pressure plate (42). The moving mold pressure plate (42) has a through hole in the center for installing the moving mold insert (43). The fixed mold (1) is installed on the upper surface of the moving mold (4). The lower surface of the moving mold (4) is provided with a support plate (5). The push rod (7) passes through the support plate (5) and the moving mold insert (43) and abuts against the lower surface of the ceramic insulating substrate. The conductive material is die-cast and filled into the reserved conductive circuit channel. Specifically, the conductive material is filled into the reserved conductive circuit channel of the ceramic insulating substrate using a cold chamber die-casting process. The die-casting pressure of the cold chamber die-casting is 15~100MPa. After the conductive material cools and solidifies, the mold is opened and post-processing is carried out.

2. The integrated manufacturing method for multilayer printed circuit boards according to claim 1, characterized in that, The ceramic insulating substrate of the multilayer printed circuit board is made of silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, or zirconium oxide.

3. A multilayer printed circuit board manufactured by the integrated manufacturing method of a multilayer printed circuit board according to any one of claims 1-2.

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