Method and device for realizing three-dimensional circuit manufacturing process

Abstract

The invention relates to the technical field of three-dimensional circuit manufacturing processes, and discloses a three-dimensional circuit manufacturing process implementation method and device, and the method comprises the steps: preparing a base material, and manufacturing a carrier of a three-dimensional circuit; shielding a non-circuit area on the surface of the base material as required; the base material is placed in a vacuum cavity, before formal vacuum metal sputtering, plasma surface cleaning and roughening are conducted on the surface of the base material, and vacuum sputtering is conducted; performing laser forming on the surface of the metal coating substrate; when the thickness of the vacuum sputtering plating layer of the base material does not meet the design requirement of a finished product, the plating layer of the three-dimensional circuit base material after laser forming is thickened; and carrying out surface passivation treatment on the three-dimensional circuit base material which is subjected to laser forming and has the plating thickness meeting the requirement, so as to obtain a finished product of the three-dimensional circuit. According to the invention, the problem that the three-dimensional circuit process has too many restrictions on materials and many materials cannot be used for manufacturing three-dimensional circuits is solved, the accuracy and consistency of circuit patterns are ensured, and the production efficiency is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of three-dimensional circuit manufacturing technology, and in particular to a three-dimensional circuit manufacturing technology implementation method and device. Background Art

[0002] Traditional three-dimensional circuit manufacturing processes mainly include LDS (laser direct forming), LAP / SPS and PEP (deposition of nickel layer on plastic surface, combined with laser segmentation and water electroplating process to prepare circuit on plastic surface) and other technologies. LAP / SPS is a domestically developed alternative process to LDS. In this process, no LDS modified components are added to the substrate material. The plastic surface is roughened by laser forming (in the circuit area, the molecular chain of the plastic surface is broken and decomposed by the laser beam to produce numerous micropores), forming a surface structure with good adsorption capacity for chemical plating active components, and depositing metal nickel and copper in the circuit area to make three-dimensional circuits through the activation of chemical plating solution. These processes have many limitations in practical applications. The current three-dimensional circuit manufacturing process can often only be applied to specific plastic materials. For example, the LDS process requires the use of specially modified plastics, which not only greatly increases the material cost, but also limits the scope of application of the process; the current LAP / SPS process can often only use PC materials or part of PC and ABS mixtures for actual mass production (in this case, the ABS content needs to be controlled).

[0003] In the prior art, the liquid medicine used in the chemical plating or electroplating process is corrosive to a certain extent, which makes it impossible to use these processes to prepare three-dimensional circuits on the surface of plastic bracket substrates reinforced with lightweight metals such as aluminum and magnesium or their alloys. This situation seriously limits and affects the application of three-dimensional circuit technology in high-end mobile phone products. In the design of high-end mobile phone products, lightweight and thin are important design considerations. The coating thickness of the three-dimensional circuit process is usually only about 10 microns (much lower than the thickness of the soft board), which is very valuable for the thin and integrated design of high-end mobile phones. However, in order to reduce the weight of the mobile phone and increase the structural strength of the product, the plastic bracket of the circuit often needs to be reinforced with lightweight high-strength aluminum alloys. Once the plastic bracket uses lightweight aluminum and magnesium metals or their alloys to enhance the structural strength, the LDS process or LAP / SPS process cannot be used. The PEP process also has the same problem. At the same time, the common overflow plating problems in the existing processes, such as dust overflow plating in the LDS process, glass fiber overflow plating in the LAP / SPS process, and line thickness fluctuations caused by uneven electric field strength in the PEP process, have a certain impact on product quality and performance, especially in high-precision application scenarios. Summary of the invention

[0004] The present invention provides a method and device for realizing a three-dimensional circuit manufacturing process, which ensures the accuracy and consistency of circuit patterns and significantly improves production efficiency.

[0005] In a first aspect, the present invention provides a method for implementing a three-dimensional circuit manufacturing process, the three-dimensional circuit manufacturing process implementing method comprising:

[0006] S1. Substrate preparation steps: When making circuits on the surface of a metal substrate, the surface of the metal substrate must first be coated with insulating material; plastic carriers are produced by injection molding, and ceramic products are produced by die casting and sintering processes;

[0007] S2, surface shielding step: when the area of ​​the non-circuit region exceeds a threshold, a shielding fixture is used to shield the non-circuit region to obtain a partially shielded substrate;

[0008] S3, vacuum sputtering step: placing the substrate in a vacuum sputtering chamber, firstly performing plasma cleaning and roughening on the surface of the substrate, and then performing cathode sputtering to deposit the target metal on the exposed surface of the substrate to obtain a metal-plated substrate;

[0009] S4, laser circuit forming step: performing laser forming processing on the surface of the metal-plated substrate to obtain a formed three-dimensional circuit substrate;

[0010] S5, coating thickening step: when the coating thickness of vacuum sputtering does not meet the design requirements, the three-dimensional circuit substrate after laser forming is thickened by chemical plating or electroplating to obtain a three-dimensional circuit substrate with thickened coating;

[0011] S6, surface passivation treatment step: using a passivation solution to perform passivation protection treatment on the coating surface of the three-dimensional circuit substrate to obtain a finished three-dimensional circuit.

[0012] In a second aspect, the present invention provides a three-dimensional circuit manufacturing process implementation device, which is used to execute the above-mentioned three-dimensional circuit manufacturing process implementation method.

[0013] In the technical solution provided by the present invention, the present invention uses vacuum sputtering technology to cover the metal coating on the surface of the substrate, breaking through the limitation of the traditional three-dimensional circuit process on materials, and can make three-dimensional circuits on the surface of almost all solid materials, significantly expanding the application range of the process. Through the precisely controlled vacuum sputtering and laser forming process, the overflow plating problem in the traditional process is effectively solved, the accuracy and consistency of the circuit are improved, and it is particularly suitable for the manufacture of high-precision application scenarios such as millimeter-wave radar and high-frequency radio frequency antennas. The plasma surface treatment combined with vacuum sputtering technology ensures the good bonding force between the metal coating and the substrate, and improves the reliability and service life of the product. The introduction of a new passivation protection technology to replace the traditional nickel plating passivation or gold plating process not only ensures the welding performance and antioxidant ability of the product, but also effectively reduces the production cost. When vacuum sputtering is used to directly achieve the required coating thickness, the pollution problem of traditional chemical plating and electroplating processes can be avoided, water resource consumption can be reduced, and a cleaner production environment can be provided. By strictly controlling the laser processing parameters and surface treatment process, the accuracy and consistency of the circuit pattern are ensured, and the three-dimensional circuit manufacturing requirements of high-precision electronic products are better met. The modular process design combined with automated equipment operation has significantly improved production efficiency, shortened product manufacturing cycle and reduced production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0015] Figure 1 Schematic diagram of the steps of a method for implementing a three-dimensional circuit manufacturing process in an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The embodiment of the present invention provides a method and device for implementing a three-dimensional circuit manufacturing process. The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] For ease of understanding, the specific process of the embodiment of the present invention is described below. Figure 1 An embodiment of a method for implementing a three-dimensional circuit manufacturing process in an embodiment of the present invention includes:

[0018] S1. Substrate preparation steps: When making circuits on the surface of a metal substrate, the surface of the metal substrate must first be coated with insulating material; plastic carriers are produced by injection molding, and ceramic products are produced by die casting and sintering processes;

[0019] Specifically, by selecting different types of substrates, including metal conductor substrates, plastic substrates or ceramic substrates, as the basic materials to be processed. When selecting a metal conductor substrate, in order to meet the insulation requirements of the three-dimensional circuit manufacturing process, an insulating material is coated on the surface of the metal conductor substrate so that the surface of the substrate has the necessary insulation properties and provides suitable basic conditions for subsequent processes. When a plastic substrate is selected and only vacuum plating is used in the subsequent metallization process without the need for subsequent chemical plating or electroplating to thicken the coating, in order to ensure that the substrate is not easily damaged by the laser during the laser forming process, and at the same time ensure that light can penetrate the substrate, thereby avoiding the material under the coating from being ablated and damaged, the plastic particles need to have a certain light transmittance (the light transmittance ratio is not less than 10%), thereby effectively reducing the degree of heat concentration during laser processing, avoiding defects such as scorching, blackening or surface protrusions of the substrate due to the action of the laser, and ensuring process stability and product quality. If the plastic substrate is not transparent, the thickness of the metal sputtered in the subsequent vacuum sputtering is controlled at about 0.1 to 1 micron, and then the coating is thickened in the subsequent chemical plating or electroplating, so that the laser scanning of the sputtered metal coating in the non-circuit area is easy to scan cleanly without causing too much damage to the substrate. When choosing a ceramic substrate, it needs to be prepared by die casting and sintering process.

[0020] S2, surface shielding step: when the area of ​​the non-circuit region exceeds a threshold, a shielding fixture is used to shield the non-circuit region to obtain a partially shielded substrate;

[0021] Specifically, determine the position and area of ​​the non-circuit area that needs to be shielded on the substrate, use design software or other auxiliary tools to scan and calibrate the non-circuit area of ​​the substrate, and obtain the shielding area pattern of the non-circuit area, which includes specific size, outline and spatial distribution. Among them, the plastic shielding fixture is designed according to the position and graphic pattern of the shielding area. In principle, the edge outline of the shielding fixture is kept at a distance of 0.5 to 1 mm from the outline of the circuit area. In this way, the time required for laser cutting of the non-circuit area can be reduced and efficiency can be improved during subsequent processing, and the problem of missing plating / lack of plating caused by shielding the circuit area due to fixture assembly or fixture size differences during vacuum sputtering can be avoided. Based on the shielding area pattern, the shielding fixture is designed. In response to different shielding requirements, the shielding fixture is divided into two structural forms during design, namely, an integral structure for large-area shielding and a split structure for fine area shielding, so as to ensure that shielding areas of various sizes and shapes are adapted, and its functionality and economy are optimized in the integral and split structures. After the design is completed, appropriate processes and materials are selected for the manufacture of the masking fixture. In terms of material selection, in order to reduce production costs and ensure the efficiency of processing, low-cost plastic materials such as ABS are selected as the main raw materials of the masking fixture. These materials must have good dimensional stability and wear resistance to ensure that the masking fixture will not be deformed or damaged during multiple uses. The injection molding process is used for mass production of the masking fixture. This process injects the molten plastic material into the designed mold cavity through the mold, and the molded masking fixture can be obtained after cooling and solidification. In the structural design of the masking fixture, a snap-on structure is set, which matches the substrate structure. Through precise size matching and clamping mechanism, the masking fixture can be firmly fixed during installation to ensure the sealing and accuracy of the masking area. The masking fixture with a snap-on is installed in the non-line area of ​​the substrate. Through the fixed connection of the snap-on structure, the masking fixture is tightly fitted with the surface of the substrate to ensure that the masking fixture covers the non-line area well and does not significantly deviate or loosen, forming a preliminary masked substrate. A local shielding substrate that meets the process requirements is obtained.

[0022] S3, vacuum sputtering step: placing the substrate in a vacuum sputtering chamber, firstly performing plasma cleaning and roughening on the surface of the substrate, and then performing cathode sputtering to deposit the target metal on the exposed surface of the substrate to obtain a metal-plated substrate;

[0023] The substrate is placed in a vacuum chamber, and the surface of the substrate is subjected to plasma surface treatment before the metal is sputtered. In order to meet the requirements of the surface state of the substrate for subsequent processes such as vacuum sputtering, the surface of the substrate is plasma cleaned and roughened. Through the plasma cleaning treatment, oil stains, dust and other tiny pollutants attached to the surface of the substrate can be effectively removed, so that the surface of the substrate reaches a clean state, ensuring that the bonding force between the subsequent coating and the substrate is stable and reliable. The treatment process acts on the surface of the substrate through the high-energy bombardment of charged particles in the plasma, so that it forms a microscopic rough structure, and at the same time, the surface of the substrate produces charged groups, which enhances the adhesion of the coating on the surface of the substrate. The microscopic roughening structure can significantly increase the bonding area between the metal coating and the surface of the substrate, and promote the chemical bonding force of the coating through the chemical activity of the charged groups, forming a more solid coating bonding interface. When implementing the plasma roughening treatment, in order to ensure that the process effect is stable and controllable, the power and time parameters of the plasma treatment are set, and the power of the plasma treatment needs to be controlled within a first preset range to ensure that the energy intensity of the charged particles is moderate, which can effectively achieve the surface roughening effect without causing irreversible damage to the substrate surface. At the same time, the time parameter needs to be controlled within the second preset range so that the treatment can be terminated when the roughening effect reaches the optimal state to avoid affecting the physical properties of the substrate due to too long a treatment time. If the test results after vacuum sputtering show that the bonding force of the substrate is lower than the preset standard, in order to improve the adhesion performance of the metal coating, a transition layer is sputtered before sputtering the target metal. The transition layer can be a metal such as titanium chromium, or an organic coating such as ink. The main function of the transition layer is to improve the interface transition between the metal coating and the substrate surface, so that the bonding force between the two is effectively enhanced, thereby laying a stable adhesion foundation for the subsequent vacuum sputtering process.

[0024] Among them, plasma is generated by gas discharge, and the target metal is deposited on the exposed surface of the substrate by cathode sputtering to obtain a metal-coated substrate;

[0025] Specifically, in order to ensure that the sputtering process can be carried out in a stable vacuum environment, the air pressure in the vacuum chamber is gradually pumped to a preset vacuum degree. The control range of the vacuum degree is set according to the process requirements, generally in a high vacuum state, to remove air impurities and moisture in the chamber, to ensure that the surface of the substrate will not be disturbed by external impurities, and to obtain a substrate in a vacuum environment. On this basis, in order to stabilize the sputtering process, an inert gas, such as argon, is introduced into the vacuum chamber. The introduction of the inert gas is to form a stable ion environment during the discharge process, while reducing the energy fluctuation of the arc discharge, and ensuring that the metal atoms can be evenly sputtered to the surface of the substrate. At this time, the pressure of the inert gas is controlled within a third preset range to form a suitable gas environment to be discharged in the vacuum chamber. In the gas environment to be discharged, a high voltage is applied to ionize the gas in the chamber to generate plasma. Plasma is a state composed of high-energy charged particles. In order to ensure the stability and controllability of the process, a stable plasma environment is obtained by precisely controlling the discharge power. In a stable plasma environment, ions will bombard the surface of the substrate with high energy, perform ion bombardment treatment, remove residual pollutants on the surface of the substrate, including oil, oxides and microscopic dust particles, and activate the surface of the substrate by ion bombardment, providing a clean and highly adhesive surface for subsequent metal deposition, and obtaining a substrate with a clean surface. After the surface treatment of the substrate is completed, a suitable target material is selected as the metal source material. Commonly used target materials include copper, nickel or aluminum. These materials have good electrical conductivity and adhesion, and have high process applicability, which can meet the requirements of different products for circuit performance. In a stable plasma environment, cathode sputtering is performed. Through the action of the electric field, the charged particles in the plasma are accelerated to bombard the surface of the target material, sputtering out the metal atoms on the target material one by one. These sputtered high-energy metal atoms migrate in a vacuum environment and are finally evenly deposited on the surface of the clean substrate to form a metal coating film. In the metal deposition process, in order to control the coating thickness of the finished circuit, different process strategies are adopted according to the specific thickness requirements. If the thickness of the finished circuit is not more than 10 microns, you can choose to deposit the metal layer to the specified thickness by direct sputtering, eliminating the subsequent chemical plating or electroplating thickening process. If the thickness of the finished circuit is required to exceed 10 microns, in order to control costs and improve the operability of the process, the thickness of the sputtered metal layer is initially controlled within the range of 0.1-1 microns to form a uniform and well-adhesive preliminary coating substrate. If you choose to directly use vacuum sputtering to achieve the required thickness of the circuit, the best coating metal is copper or aluminum. If the final application involves the welding needs of the product's circuit, choose copper. If the coating is finally thickened to a specified thickness by chemical plating or electroplating, nickel or copper is the best choice. These two metals are relatively easy to make and inexpensive in subsequent chemical plating or electroplating thickening.

[0026] When aluminum, magnesium or any metal or alloy that will be corroded by liquid medicine during chemical plating or electroplating is used to strengthen the substrate (for example, high-strength aluminum alloy or aluminum-magnesium alloy may be used for in-mold injection molding of mobile phone injection molded parts to increase strength), in order to prevent the reinforcing metal or alloy from being corroded by liquid medicine during chemical plating or electroplating thickening, it is advisable to directly sputter the coating thickness to the specified requirements during vacuum sputtering, so that subsequent chemical plating or electroplating thickening is not required to prevent corrosion of the reinforcing metal or alloy. If vacuum sputtering is selected and then chemical plating or electroplating is used to thicken the coating, the shielding fixture cannot cover the surface of these easily corroded metal parts. During vacuum sputtering, the surface of the metal parts is covered by the sputtered metal nickel or copper. After subsequent chemical plating or electroplating thickening, the easily corroded metal underneath is protected by the vacuum sputtered coating and will not be corroded during the subsequent process (such as chemical plating or electroplating).

[0027] In order to ensure the quality stability of the finished product, the coating thickness and adhesion of the coating substrate are tested. The adhesion test verifies whether the bonding force between the coating and the substrate meets the preset process standards, ensuring that the coating will not peel off or delaminate during subsequent processing or use. If the coating adhesion does not meet the requirements, the above-mentioned vacuum sputtering process parameters need to be optimized until they meet the requirements.

[0028] S4, laser circuit forming step: treating the surface of the metal-plated substrate to obtain a formed three-dimensional circuit substrate;

[0029] Specifically, remove the masking fixture on the metal-coated substrate (note that the non-circuit area of ​​some products is small, and when the laser segmentation and clearing time is not long, it is not necessary to consider using a masking fixture to mask the non-circuit area). During the removal process, it is necessary to prevent scratches on the surface of the product substrate when the fixture is removed. After removal, the metal-coated substrate to be processed is obtained. To ensure the precise positioning of the product, a suitable laser forming positioning fixture is required during laser forming. During processing, the metal-coated substrate to be processed is placed on the product positioning fixture of the three-dimensional laser forming equipment. According to the circuit design plan of the product, determine and set the laser processing steps and the graphics of each step of laser processing. In order to ensure the effect of laser forming and the dimensional accuracy of the circuit, engineering and technical personnel fine-tune the laser processing parameters and the graphics of each step of processing according to the actual processing effect, and determine the optimal parameter settings and the final laser processing graphics and procedures. The setting of laser parameters includes: controlling the laser power within the fourth preset range to ensure that the energy intensity of the laser is sufficient to remove the metal layer in the non-circuit area without excessively damaging the substrate; controlling the scanning speed within the fifth preset range to ensure that the laser beam can act evenly and stably on the surface of the substrate, making the cutting process smoother and more accurate; at the same time, controlling the spot spacing and the filling spacing of the laser scanning within the sixth preset range to achieve precise control of the edge of the metal layer, ensuring that the outline of the circuit pattern is clear and neat, and reaching the accuracy standard required by the design drawing. When the metal-plated substrate to be processed is a plastic substrate, and no chemical plating or electroplating process is performed subsequently, in order to prevent the laser energy from causing thermal damage to the plastic substrate body during the laser cutting process, the light transmittance and processing effect of the plastic substrate are confirmed, and the light transmittance ratio of the plastic substrate is preferably not less than 10%, because when the substrate has a certain light transmittance, the laser energy can partially penetrate the substrate without excessive concentration on the surface of the substrate, thereby avoiding burning, blackening or surface damage caused by high laser energy, and ensuring that the structure and appearance of the substrate will not be significantly damaged (it is inevitable that the laser will cause a certain degree of damage to the substrate, and we need to minimize such damage as much as possible under feasible conditions). When the laser processing officially starts, according to the pre-set processing program and laser processing parameters, the metal layer that needs to be removed from the surface of the substrate is laser cut using a three-dimensional laser device. The laser beam accurately scans the surface of the substrate according to the designed path, gradually removing the metal layer in the non-circuit area, while retaining the metal layer in the circuit area, forming a clear three-dimensional circuit shape that meets the design requirements. This process requires the energy of the laser beam to be uniform and the path to be stable to avoid burrs or irregular edges during the cutting process, which will affect the dimensional accuracy and appearance quality of the final circuit. After the laser cutting is completed, in order to ensure that the initially formed circuit meets the requirements of the design drawing, its circuit size and edge contour are tested.Through high-precision measuring tools, the width, length, edge smoothness and other indicators of the line are comprehensively checked to confirm that each indicator meets the design tolerance requirements to avoid problems in subsequent processing and product performance due to dimensional errors or edge defects. In order to remove the residues generated during the laser cutting process, the surface of the product can be cleaned by ultrasonic cleaning and pickling to remove dust and oxidation after laser cutting to prepare for the next step.

[0030] S5, coating thickening step: when the coating thickness of vacuum sputtering does not meet the design requirements, the three-dimensional circuit substrate after laser forming is thickened by chemical plating or electroplating to obtain a three-dimensional circuit substrate with thickened coating;

[0031] Specifically, according to different thickening process requirements, prepare corresponding chemical copper plating solution or electroplating copper solution. In the preparation process of chemical copper plating solution, the concentration of copper sulfate is strictly controlled within the scope of 15-20g / L to provide a stable source of copper ions, and formaldehyde is added as a reducing agent to accurately control its concentration within 15-20ml / L to ensure the continuity and uniformity of the chemical reaction. In order to stabilize the copper ions in the plating solution, a complexing agent EDTA-2Na is added, and the concentration is controlled at 30-40g / L. The presence of the complexing agent helps the uniform deposition of copper ions and prevents the occurrence of excessively thick or uneven local coatings. At the same time, by adding a conditioning agent, the pH value of the solution is controlled within the scope of 12-13, and a suitable alkaline environment is conducive to the stable progress of chemical copper plating, and a group of stable chemical copper plating solutions is obtained. In terms of electroplating process, a copper electroplating solution is prepared, in which the content of copper sulfate is strictly controlled at 150-250g / L to provide sufficient copper ion concentration, and the content of sulfuric acid is maintained at 50-70g / L. The role of sulfuric acid is to improve the conductivity of the solution, ensure that the current is evenly distributed on the surface of the plated part, and avoid the uneven thickness of the coating. After sufficient stirring, the copper electroplating solution meets the process requirements. When the chemical copper plating thickening process is carried out, the circuit substrate after laser forming is immersed in the chemical copper plating solution prepared in advance, and the temperature of the solution is controlled within the range of 30-45°C to ensure that the rate of the chemical reduction reaction is stable and controllable, and through moderate mechanical stirring or gas stirring, the copper ions in the plating solution can be evenly deposited on the circuit surface of the substrate, so as to achieve stable thickening of chemical copper plating and form a copper layer with uniform thickness. If the copper electroplating process is selected, the circuit substrate with a certain conductivity after metal sputtering is used as the cathode, and the pure copper plate is used as the anode, and they are placed together in the copper electroplating solution, and the current density is controlled at 1-5A / dm 2Within the range of , copper ions migrate evenly to the circuit surface of the substrate under the action of the electric field. The electroplating time is accurately controlled by Faraday's law to ensure that the coating is gradually thickened to the thickness required by the design, while avoiding undesirable phenomena such as rough or burnt coating, forming a uniform electroplated copper layer that meets the design specifications. After the coating is thickened, in order to verify whether the thickness of the coating meets the design requirements, a thickness gauge and other high-precision instruments are used to test the thickness of the circuit substrate of chemical copper plating or electroplating copper to ensure that the coating meets the uniformity requirements on the surface of the substrate and the thickness meets the specification standards, so as to obtain a circuit substrate with qualified thickness. After confirming that the coating quality meets the requirements, the surface of the substrate is cleaned to remove the residual chemical copper plating solution or electroplating copper solution to avoid the long-term influence of corrosive substances on the coating, while ensuring the cleanliness of the circuit surface.

[0032] S6, surface passivation treatment step: using a passivation solution to perform passivation protection treatment on the coating surface of the three-dimensional circuit substrate to obtain a finished three-dimensional circuit.

[0033] For example, in vacuum aluminum plating, aluminum will form a dense oxide film after being oxidized in the air to prevent further corrosion. Generally, vacuum aluminum plating does not require special surface treatment. If the metal layer of the circuit is copper, the conventional copper protection method in the current three-dimensional circuit industry is to plate nickel on the surface of the copper and then passivate the nickel layer for protection. The present invention uses a direct passivation method of copper to protect the copper layer, which is energy-saving, consumption-reducing and environmentally friendly. The specific operation is as follows:

[0034] Different copper passivation solutions have different passivation effects and process details and effects. After the copper layer is passivated with copper passivation solution (XZG049), it can meet the requirements of neutral salt spray test for 48 hours or even more than 96 hours. The specific operating details of using this passivation solution are as follows: Solution concentration control: It depends on the requirements of the salt spray test after passivation, and the solution concentration is controlled at more than 10%. If the salt spray test requires more than 96 hours, 100% stock solution is required for passivation. Passivation temperature control: The temperature of the passivation solution is adjusted to 25-35°C, which is the best temperature range for passivation treatment. It can ensure the stability of the reaction rate and the uniform formation of the passivation layer. At the same time, the temperature is maintained stable and does not fluctuate through the temperature control device to obtain a passivation solution with constant temperature. Passivation time: The immersion time is in the range of 1-10 minutes. According to the specific process requirements and the corrosion protection requirements of the circuit substrate, the length of the immersion time can be adjusted appropriately. During this process, the passivation liquid reacts chemically with the surface of the circuit substrate, gradually forming a dense passivation film on the metal surface. This protective film has good anti-oxidation and corrosion resistance.

[0035] After the soaking time is over, the circuit substrate that has been passivated is taken out of the passivation solution. In order to prevent the residual passivation solution from affecting the performance of the passivation film, the surface of the substrate is cleaned to remove all residual passivation solutions to ensure that the surface of the substrate is in a clean state to avoid affecting the subsequent performance test and the final quality of the finished product. The cleaned passivated substrate is subjected to hot air drying. During the drying process, the temperature must be strictly controlled within the seventh preset range. Too high a temperature may cause deformation of the plastic substrate, and too low a temperature may cause residual moisture, affecting the long-term stability of the circuit substrate. Through the hot air drying technology, the clean surface of the passivated substrate is gradually dried to obtain a dry passivated substrate containing a uniform and stable passivation film. In order to verify the passivation treatment effect and the reliability of the passivation film, the dry passivated substrate is placed in a neutral salt spray test chamber for corrosion resistance testing. The test time must be no less than 48 hours. By simulating humid and corrosive environmental conditions, the stability and protection effect of the passivation film under harsh conditions are evaluated to ensure that the substrate surface has good corrosion resistance and meets the process standard requirements. After the neutral salt spray test is completed and the corrosion resistance of the substrate is confirmed to be qualified, when the finished circuit needs to be welded, the welding performance of the passivated circuit is tested and verified to check whether there is any shedding, cracks or other abnormal phenomena during the welding process to ensure that the welding requirements of the product are met. Only when the corrosion resistance and welding performance of the passivated substrate meet the design standards can it be judged as a substrate with qualified performance. The substrate with qualified performance is fully inspected in terms of size and appearance. Through high-precision measuring equipment, the key parameters of the substrate such as line size, thickness, edge profile, etc. are fully inspected to ensure that all quality indicators meet the product specifications. At the same time, the appearance quality of the substrate is visually inspected, and there are no scratches, dents or other defects that affect the product function on the surface, so as to ensure that the overall quality of the finished product is stable and reliable. After completing the full inspection of size and appearance, a finished three-dimensional circuit that meets the product specifications is obtained.

[0036] In the embodiment of the present invention, the present invention uses vacuum sputtering technology to cover the metal coating on the surface of the substrate, breaking through the limitation of the traditional process on the material, and can make three-dimensional circuits on the surface of almost all solid materials, which significantly expands the application scope of the process. Through the precisely controlled vacuum sputtering and laser forming process, the overflow plating problem in the traditional process is effectively solved, the accuracy and consistency of the circuit are improved, and it is particularly suitable for the manufacture of high-precision application scenarios such as millimeter wave radar and high-frequency radio frequency antenna. The plasma surface treatment combined with vacuum sputtering technology ensures the good bonding force between the metal coating and the substrate, and improves the reliability and service life of the product. The introduction of new passivation protection technology to replace the traditional nickel plating passivation or gold plating process not only ensures the welding performance and antioxidant ability of the product, but also effectively reduces the production cost. When vacuum sputtering is used to directly achieve the required coating thickness, the pollution problem of traditional chemical plating and electroplating processes can be avoided, water resource consumption can be reduced, and a cleaner production environment can be provided. Through strictly controlled laser processing parameters and surface treatment processes, the accuracy and consistency of the circuit graphics are ensured, and the manufacturing requirements of high-precision electronic products are met. The modular process flow design is adopted, combined with the operation of automated equipment, which significantly improves the production efficiency and shortens the product manufacturing cycle.

[0037] In a specific embodiment, the process of executing step S1 may specifically include the following steps:

[0038] Selecting a metal conductor substrate, a plastic substrate or a ceramic substrate as the substrate to be processed;

[0039] When a metal conductor substrate is selected, an insulating material is coated on the surface of the metal conductor substrate; when a plastic substrate is selected, an injection molding process is used for preparation, such as the subsequent coating is directly thickened to the thickness required by the design through vacuum sputtering, and the plastic particles used for injection molding should have a certain light transmittance, such as more than 10%, to prevent the subsequent laser processing from causing serious damage to the plastic substrate; when a ceramic substrate is selected, a die-casting and sintering process is used for preparation;

[0040] When a ceramic substrate is selected, it is prepared by die casting and sintering processes to ensure its density and surface flatness. The molding pressure P during the die casting process is given by the formula Calculate, where F is the force and A is the area of ​​the mold. Appropriate pressure can fully compact the ceramic particles, thereby reducing the shrinkage rate in subsequent sintering and forming a ceramic substrate with excellent insulation properties. The temperature control in the sintering process is based on the sintering curve of the material. By accurately controlling the temperature and time, the structural uniformity and insulation properties of the ceramic substrate are ensured.

[0041] In a specific embodiment, the process of executing step S2 may specifically include the following steps:

[0042] Determine the position and area of ​​the non-line area that needs to be shielded, and obtain a shielding area pattern;

[0043] Designing a plastic shielding fixture according to the shielding area pattern, the plastic shielding fixture includes an integral structure for shielding a large area and a split structure for shielding a local area;

[0044] The plastic shielding fixture is manufactured by injection molding process, and the material of the plastic shielding fixture is selected from low-cost plastic materials such as ABS to obtain a molded shielding fixture;

[0045] A buckle structure is arranged on the formed shielding fixture, and the buckle structure matches the substrate to obtain a shielding fixture with a buckle;

[0046] Installing a shielding fixture with a buckle on a non-circuit area of ​​the substrate and fixing the connection through a buckle structure to obtain a preliminarily shielded substrate;

[0047] Check the installation tightness of the masking fixture on the initially masked substrate to ensure that the masking fixture fits the substrate surface without gaps to obtain a sealed masked substrate;

[0048] Perform a visual inspection of the sealed masked substrate to confirm the completeness and accuracy of the masked area.

[0049] Specifically, when designing a masking fixture, according to the design of the substrate and the finished circuit, use 3D design software such as Pro-E to perform 3D modeling on the computer. When 3D modeling, the accuracy of the fixture fitting to the substrate surface and the size of the area to be masked need to be considered. The overall structural dimensions of the masking fixture are slightly smaller than the area of ​​the non-circuit area (designed along the periphery of the circuit area, the outline of the fixture and the outline of the circuit area are kept at a distance of 0.5 to 1.5 mm, so that the coating area covered on the surface of the product by vacuum sputtering is slightly larger than the design area of ​​the circuit. In subsequent laser forming, the laser processing time can be reduced without causing the problem of leakage plating during vacuum sputtering in the circuit area due to the difference in fixture position and external dimensions). The masking fixture is manufactured using the injection molding process, and low-cost plastic materials (such as polypropylene or ABS) are selected. These materials have good formability and durability, and are also low-priced.

[0050] In order to ensure that the masking fixture can be firmly fixed on the substrate surface, a snap-on structure is provided on the molded masking fixture. The snap-on structure must be designed to ensure that it can match the shape of the substrate surface and has sufficient clamping force F. c The clamping force is given by the formula F c=k·Δx calculation, where k is the elastic coefficient of the buckle material and Δx is the deformation of the buckle. The elastic design of the buckle structure can achieve quick installation and disassembly, while ensuring that the fixture will not loosen or shift during operation, forming a shielding fixture with a buckle. When the shielding fixture with a buckle is installed in the non-circuit area of ​​the substrate, it is fixedly connected to the surface of the substrate through the buckle structure to form a preliminary shielded substrate. When assembling the shielding fixture, ensure that all buckles are in a tightly connected state so that the shielding fixture and the surface of the substrate are fully fitted. After the shielding fixture is assembled, in order to verify the shielding effect, it is necessary to detect the installation tightness of the shielding fixture on the preliminary shielded substrate. The shielding fixture can only cover the non-circuit area and must not cover the circuit area, otherwise it will cause the problem of missing circuit area of ​​the finished product. If necessary, a qualified finished product with a complete circuit can be used to install the shielding fixture for comparison. The shielding fixture should have a certain gap (about 0.5 to 1.5 mm) with the circuit area of ​​the finished product.

[0051] In a specific embodiment, the process of executing step S3 may specifically include the following steps:

[0052] After placing the substrate to be vacuum plated into a vacuum chamber, a vacuum sputtering device is first used to perform plasma surface treatment on the surface of the substrate.

[0053] When the substrate surface is treated with plasma cleaning, charged particles bombard the substrate surface to form microscopic rough structures and charged groups, resulting in a roughened substrate surface. At the same time, some pollutants on the substrate surface can also be removed or decomposed to a certain extent during the plasma bombardment process. This plasma surface treatment can significantly improve the adhesion between the subsequent vacuum sputtered coating and the substrate, especially when vacuum sputtering metal coatings on plastic substrate surfaces.

[0054] Setting the power and time parameters of the plasma treatment, wherein the power is controlled within a first preset range and the time parameter is controlled within a second preset range. Introducing an inert gas into the vacuum chamber, controlling the gas pressure within a third preset range, and obtaining a gas environment to be discharged;

[0055] Performing gas discharge in a gas environment to be discharged to generate plasma, and obtaining a stable plasma environment by controlling the discharge power;

[0056] The partially shielded substrate surface is treated with ion bombardment in a plasma environment to remove surface pollutants and obtain a substrate with a clean surface and a certain degree of roughening, in preparation for the next step of vacuum plating.

[0057] Energy density E of plasma surface treatment p By formula Calculation, where P is the plasma power and A is the surface area of ​​the substrate. The appropriate energy density ensures that the substrate surface is clean without damaging the material itself, and finally a substrate with a clean surface is obtained. At the same time, through the continuous bombardment of high-energy charged particles, microscopic rough structures and active charged groups are formed on the surface of the substrate, which improves the adhesion of the coating. One of the quantitative indicators of the roughening effect is the surface roughness R a , and its calculation formula is Where L is the measurement length, and y(x) is the height function of the surface deviation from the average value. The higher the roughness, the stronger the mechanical bonding between the substrate surface and the coating. At the same time, the chemical bonding of the coating is enhanced through the chemical activity of the charged groups. In order to achieve the best roughening effect, the power and time parameters of the plasma treatment are set according to the characteristics of the substrate. The power P should be controlled within a first preset range, and its value is calculated by the formula P=V·I, where V is the applied voltage and I is the plasma discharge current. The time parameter t is set within a second preset range based on the requirements of the roughening effect. After the plasma surface treatment is completed, vacuum test sputtering is carried out. When the sputtering reaches a certain thickness, the surface roughening effect is verified by an adhesion test. The peel strength F of the adhesion test s By formula Calculated, where F is the peel force and w is the width of the test sample. Only when the peel strength reaches the process standard can it be judged as a qualified surface activated substrate. However, in some cases, even if the roughening effect has reached a certain level, if the adhesion test results show that the bonding force of the substrate is still lower than the preset standard, in order to improve the adhesion performance of the coating, it is possible to consider spraying a transition layer on the substrate. A suitable transition layer can optimize the physical and chemical properties of the substrate surface and provide a guarantee for the stability of subsequent processes. In addition to spraying a transition layer on the surface, vacuum sputtering of transition metals is also an effective method. Titanium, chromium, nickel and aluminum are several commonly considered sputtering coating metals.

[0058] Vacuum sputtering target metal layer:

[0059] Select the appropriate metal target for sputtering according to the design requirements of the circuit and the arrangement of the entire process. If the coating is directly thickened to the target thickness by vacuum sputtering, copper or aluminum is the best choice; if the coating is thickened by subsequent chemical plating and electroplating, nickel or copper is the best option.

[0060] Copper, nickel or aluminum is selected as the target material, and cathode sputtering is performed in a plasma environment to obtain the metal atoms to be deposited; when a transition layer is needed to improve the bonding strength of the coating, the best transition layer metal needs to be determined through trial production and specific adhesion tests.

[0061] Specifically, to provide an environment suitable for metal deposition, the air pressure in the vacuum chamber is pumped to a preset vacuum level. The control of the vacuum level needs to reach a high vacuum level, such as P v <10 -3 Pa, to remove impurity gases and water vapor in the air that affect sputtering deposition. The calculation formula for the vacuum level P v is where N represents the number of gas molecules, k is the Boltzmann constant, T is the gas temperature, and V is the volume of the vacuum chamber. As the vacuum pump operates, the number of gas molecules gradually decreases. After the vacuum level reaches the preset range, the substrate is in an ideal vacuum environment. To optimize the vacuum environment, an inert gas (such as argon) is introduced into the chamber. The role of the inert gas is to provide a stable discharge medium and avoid the influence of chemical reactions on the surface of the substrate. The gas pressure P g in the chamber is precisely controlled within a third preset range, such as 1 Pa < P g < 10 Pa. The setting formula for the pressure P g is where F is the applied force and A is the cross-sectional area of the chamber. By adjusting the combined action of the gas flow rate and the vacuum pump, a stable gas environment to be discharged is formed in the chamber. In the gas environment to be discharged, gas discharge is carried out by applying a high-voltage electric field to generate plasma. Plasma is a quasi-neutral gas state containing free electrons and charged ions, with good electrical conductivity and chemical activity. The discharge power P is a key parameter for generating a stable plasma environment, and its formula is P = V·I, where V is the discharge voltage and I is the discharge current. By adjusting the electric field strength and gas pressure, the discharge power is controlled within a suitable range, such as 50 W < P < 500 W, so as to generate a uniform and stable plasma. The surface of the substrate is treated by ion bombardment with high-energy ions in the plasma. During the bombardment process, high-speed charged particles continuously impact the surface of the substrate, thereby removing pollutants (such as oil stains, oxides, and dust particles) and further activating the surface. The bombardment energy density E is calculated by the formula where m is the ion mass and v is the ion velocity. By adjusting the plasma parameters, it is ensured that the energy of the ion bombardment is sufficient to clean the surface of the substrate without causing physical damage to it, and a substrate with a clean surface is obtained. After the surface cleaning is completed, copper, nickel, or aluminum is selected as the target material, and metal atoms are sputtered from the surface of the target material by cathode sputtering. In the plasma environment, positively charged argon ions impact the surface of the target material with high energy, and the metal atoms on the target material are sputtered out due to the transfer of kinetic energy. The sputtering rate R is calculated by the formula Calculation, where η is the target sputtering coefficient, E is the energy of the bombarding particles, and W is the binding energy of the metal atoms. These sputtered metal atoms migrate in the cavity with a certain kinetic energy, and are eventually deposited on the surface of the substrate to form a uniform metal film. During the deposition process, different process strategies are selected according to the thickness requirements of the finished circuit. When the circuit thickness requirement does not exceed 10 microns, direct sputtering to the specified thickness can be considered. When the thickness requirement exceeds 10 microns, the thickness of the sputtered metal layer is initially controlled within the range of 0.1-1 microns to form a thin metal base layer. After the metal deposition is completed, the coating thickness and adhesion of the preliminary coated substrate are tested. The coating thickness can be tested using a film thickness tester. The adhesion is verified by a peel strength test, and its peel strength F s The formula is Where F is the peeling force and w is the width of the test sample. Only when the adhesion test results meet the process standards can it be determined as a qualified coating substrate. The qualified coating substrate is taken out of the vacuum chamber to obtain a metal coating substrate that meets the requirements. Then enter the next process.

[0062] In a specific embodiment, the process of executing step S4 may specifically include the following steps:

[0063] Load the metal-plated substrate to be processed into the three-dimensional laser forming equipment (if a masking fixture is used in the non-sputtering area of ​​the substrate surface during vacuum sputtering, remove the masking fixture first), import the design pattern and generate the laser processing path to obtain the processing program;

[0064] The laser processing parameters are set according to the processing program, including controlling the laser power within a fourth preset range, controlling the scanning speed within a fifth preset range, and controlling the spot spacing and the filling spacing within a sixth preset range, to obtain the laser processing parameter settings;

[0065] When the metal-plated substrate to be processed is a plastic substrate and there is no subsequent electroplating process, the light transmittance ratio of the plastic substrate is tested to confirm that the light transmittance ratio should not be less than 10%;

[0066] According to the processing procedure and the laser processing parameter settings, the metal layer on the surface of the substrate is laser cut, the metal layer in the circuit area is retained, and the metal layer in the non-circuit area is removed to obtain a cut circuit substrate;

[0067] Detect the circuit size and edge profile of the cut circuit substrate to ensure that the design tolerance requirements are met and a qualified circuit substrate is obtained;

[0068] The surface of the circuit substrate that has passed the inspection is cleaned to remove the residues produced by laser cutting to obtain a circuit substrate with a clean surface, and the conductivity of the circuit substrate with a clean surface is tested to ensure that the circuit pattern is complete without open circuits to obtain a formed three-dimensional circuit substrate.

[0069] Specifically, the shielding fixture on the metal-plated substrate is removed (when covered by the shielding fixture). During the removal process, ensure that the metal coating on the surface of the substrate is not damaged to maintain its integrity. The substrate is loaded into a three-dimensional laser forming device, and the pre-designed pattern of the area where the metal coating needs to be removed by laser cutting and scanning is imported through the software interface of the device. The pattern is represented in a vector file format (such as DXF or SVG) and can provide accurate geometric information. The laser processing path is generated by the system algorithm, and the processing path covers the area that needs laser scanning in an optimized manner to generate a complete processing program. After the processing program is generated, the process parameters of the laser processing equipment are set. The key parameters of laser processing include laser power, scanning speed, spot spacing and filling spacing. The laser power P determines the cutting depth and efficiency of the laser on the metal coating, and the formula is P=E / t, where E is the laser energy and t is time. The laser power is controlled within the fourth preset range to ensure that the metal layer in the non-circuit area can be effectively removed without causing obvious damage to the substrate. The scanning speed v determines how fast the laser beam moves. The formula is v = d / t, where d is the distance the laser head moves and t is the time required. The scanning speed is controlled within the fifth preset range to balance cutting accuracy and processing efficiency. The spot size D directly affects the cutting width. Its value is determined by the focal length of the lens and the laser wavelength. The formula D = 1.27·λ·(f / D L ), where λ is the laser wavelength, f is the focal length of the lens, and D L is the laser beam diameter. The spot diameter of the laser equipment is generally fixed. The spot spacing and fill spacing are set in the sixth preset range to ensure that the line edge is clear without redundant cutting. For plastic substrates without subsequent chemical plating or electroplating processes, the transmittance ratio of the plastic substrate is detected to verify whether it meets the transmittance requirements of laser processing. The formula for the transmittance ratio T is T = (I t / I0)×100%, where I t is the transmitted light intensity, and I0 is the incident light intensity. The transmittance ratio of the plastic substrate is measured by a photometer. The transmittance ratio should not be less than 10% to avoid significant damage to the substrate when the coating on the surface of the substrate is laser cut. The metal layer in the non-circuit area on the surface of the substrate is laser cut according to the processing procedure and laser processing parameter settings. The principle of laser cutting is to use a high-energy laser beam to focus on the surface of the metal layer to generate a high enough temperature to melt or vaporize the metal material. During the cutting process, the laser equipment retains the metal layer in the circuit area according to the processing procedure, and removes the metal layer in the non-circuit area to form a preliminary cut circuit substrate with clear boundaries. After the cutting is completed, the circuit size and edge contour of the circuit substrate are inspected to ensure that it meets the design tolerance requirements. Dimension detection is performed using image measuring equipment, and the tolerance range is given by the formula Δ=|L m -L dOK, where L m is the actual measured value, L d is the design value, and Δ is the deviation. If the deviation Δ is less than the specified allowable tolerance value, it is considered qualified. The edge profile detection is observed through a high-resolution microscope to ensure that there are no burrs or melting marks on the cutting edge. After confirming that the circuit size and edge profile meet the requirements, the surface of the circuit substrate that has passed the inspection is cleaned.

[0070] Among them, the metal-coated substrate to be processed is loaded into the three-dimensional laser forming equipment, the design drawing is imported and the laser processing path is generated, and the processing procedure is obtained, which specifically includes: according to the three-dimensional structural characteristics of the metal-coated substrate to be processed, a three-dimensional scanner is used to scan the surface contour of the substrate to generate a three-dimensional digital model of the substrate, and the three-dimensional digital model is imported into the computer-aided design system to obtain the digital surface information of the substrate. If the substrate has a 3D design model, the subsequent laser programming directly uses this 3D model; according to the circuit layout drawing of the product design, the graphics of the non-circuit area that needs to be laser scanned are determined, and the graphics are converted into a vector graphics format, and in the computer-aided design system, the vector graphics and the digital surface information are matched in three-dimensional space to obtain a three-dimensional non-circuit area (Note: This area is the area that the laser needs to cut and scan) design drawing; the starting point, end point and key control point of the laser processing are marked on the three-dimensional non-circuit area design drawing, and the processing parameters of each line segment are set according to the width and depth requirements of the line to obtain a parameterized processing trajectory; the path optimization is used The parameterized processing trajectory is calculated by a quantized algorithm, and the processing order of adjacent line segments is optimized and sorted by comprehensively considering the processing efficiency and heat accumulation effect to obtain an optimized processing sequence; according to the optimized processing sequence, the three-dimensional motion trajectory of the laser beam is set, including the displacement and angle adjustment value of the X, Y, and Z axes, and the laser focal length is dynamically adjusted according to the curvature change of the substrate surface to obtain a compensated processing path; a processing coordinate system is established in the control system of the three-dimensional laser forming equipment, the positioning reference point of the substrate is aligned and checked with the equipment coordinate system, and the position is corrected through the visual positioning system to obtain a calibrated processing reference; the compensated processing path is converted into a CNC code that can be recognized by the equipment, and the processing code is optimized in timing according to the characteristic parameters of the laser, including the power response time and the spot size, to obtain precise control instructions; a processing parameter database is established on the operation interface of the three-dimensional laser forming equipment, and precise control instructions are associated with process parameters, and process verification and parameter fine-tuning are performed through the human-computer interaction interface to obtain an executable processing program.

[0071] In a specific embodiment, the process of executing step S5 may specifically include the following steps:

[0072] When it is necessary to thicken the vacuum sputtered coating by chemical plating or electroplating:

[0073] If chemical plating is used for thickening, a chemical copper plating solution is prepared, the concentration of copper sulfate is controlled to be 15-20 g / L, the concentration of reducing agent formaldehyde is controlled to be 15-20 ml / L, the concentration of complexing agent EDTA-2Na is controlled to be 30-40 g / L, and the pH value is adjusted to 12-13 to obtain a chemical copper plating solution;

[0074] If electroplating thickening is selected, a copper electroplating solution is prepared, and the copper sulfate content is controlled to be 150-250g / L and the sulfuric acid content is 50-70g / L to obtain a copper electroplating solution;

[0075] When the chemical copper plating process is adopted, the circuit substrate is immersed in a chemical copper plating solution, the solution temperature is controlled within the range of 30-45°C, and the stirring speed of the plating solution is controlled to obtain a circuit substrate with chemical copper plating;

[0076] When using the copper electroplating process, in the copper electroplating solution, the circuit substrate is used as the cathode and the pure copper plate is used as the anode, and the current density is controlled at 1-5A / dm 2 Within the range, a circuit substrate of electroplated copper is obtained;

[0077] Measure the coating thickness of chemically plated copper or electroplated copper circuit substrates to ensure that the design specifications are met and that the thickness of the circuit substrate is qualified. The thickness of the copper coating after electroplating or chemical plating is generally 7 to 18 microns. The copper thickness of some products may reach about 25 microns.

[0078] The surface of the circuit substrate with qualified thickness is cleaned, and the residual chemical copper plating solution or electrolytic copper plating solution is removed to obtain a circuit substrate with a clean surface, and the circuit substrate with a clean surface is dried to obtain a three-dimensional circuit substrate with a thickened coating.

[0079] Specifically, in order to thicken the coating, a suitable copper plating solution is prepared. If a chemical copper plating process is used, a chemical copper plating solution is prepared, and its chemical composition and parameters are strictly controlled. The main component of the solution is copper sulfate, and its concentration is accurately controlled within the range of 15-20g / L to provide a stable source of copper ions. The concentration of formaldehyde as a reducing agent is set at 15-20ml / L to ensure the deposition rate and uniformity of the coating. The concentration of the complexing agent EDTA-2Na needs to be maintained between 30-40g / L to stabilize copper ions and prevent unnecessary precipitation reactions in the solution. To ensure that the chemical reaction is carried out in a suitable alkaline environment, the pH value of the solution needs to be adjusted to 12-13. By stirring and heating equipment, ensure that the chemical copper plating solution is evenly mixed and remains stable. If an electroplating copper process is selected, an electroplating copper solution needs to be prepared, in which the content of copper sulfate needs to be accurately controlled within the range of 150-250g / L to provide sufficient copper ion concentration. The content of sulfuric acid is set to 50-70g / L, which is used to improve the conductivity of the solution and ensure the uniform distribution of current during the electroplating process. By filtering and stirring the solution, impurities are eliminated and the cleanliness of the electroplating solution is guaranteed. When using the chemical copper plating process, the circuit substrate is immersed in a pre-prepared chemical copper plating solution. The chemical plating process is to reduce copper ions and evenly deposit them on the circuit area surface of the substrate through a chemical reaction in the solution. In order to ensure the quality of the coating, the temperature of the solution is controlled within the range of 30-45°C. The temperature adjustment formula is T=T s +ΔT, where T is the actual temperature, T s is the starting temperature, and ΔT is the adjustment increment. At the same time, the plating solution is maintained to flow evenly by a stirring device. After a certain period of chemical reaction, the copper plating layer is evenly deposited on the surface of the substrate to obtain a circuit substrate of chemical copper plating. When the electroplating copper process is adopted, the circuit substrate is used as the cathode in the electroplating equipment, and a pure copper plate is used as the anode, and both are placed in the electroplating copper solution. Note that when using electroplating to thicken the circuit, each area of ​​the circuit needs to use a suitable hanger to connect the circuit area and the cathode. After power-on, the current density J is controlled within the range of 1-5A / dm2, and its calculation formula is Where I is the applied current and A is the effective area of ​​the cathode. Through electrochemical reaction, copper ions are reduced from the solution and uniformly deposited on the surface of the circuit substrate. According to the current density and the power-on time, the coating thickness d is given by the formula Calculation, where M is the molar mass of copper, z is the number of electron transfers, t is the power-on time, n is the Faraday constant, and F is the power-on area. The thickness of the coating is precisely controlled by adjusting the current density and time. Regardless of whether chemical copper plating or electroplating copper is used, the thickness of the coating must be tested after the coating deposition is completed. The coating thickness d is measured using an X-ray thickness gauge. If the thickness meets the design specifications, it is determined to be a circuit substrate with a qualified thickness. To ensure the long-term stability of the coating, the circuit substrate with a qualified thickness is cleaned. During the cleaning process, the water flow intensity is controlled to ensure thorough cleaning.

[0080] In a specific embodiment, the process of executing step S6 may specifically include the following steps:

[0081] Prepare a passivation treatment solution. When it is necessary to pass a 96-hour neutral salt spray test, use a 100% concentration of passivation solution to obtain a passivation solution for treatment;

[0082] The temperature of the passivation solution for treatment is adjusted to within the range of 25-35°C and the temperature is kept stable to obtain a passivation solution with a constant temperature;

[0083] The three-dimensional circuit substrate with thickened coating is immersed in a passivation solution with constant temperature, and the immersion time is controlled within the range of 1-10 minutes to obtain a passivated circuit substrate;

[0084] The passivated circuit substrate is taken out from the passivation solution, the surface is cleaned, and the residual passivation solution is removed to obtain a passivated substrate with a clean surface;

[0085] The clean surface of the passivation substrate is dried by hot air, and the drying temperature is controlled within a seventh preset range to obtain a dry passivation substrate;

[0086] After the passivation is completed, the products are sampled and tested. The content of the sampling test may include but is not limited to salt spray test, solderability test, etc.

[0087] The dried passivated substrate is placed in a neutral salt spray test chamber for testing for no less than 48 hours to obtain a substrate with qualified corrosion resistance. When the product circuit needs to be welded, a welding performance test needs to be arranged to ensure that the design standard is met and a substrate with qualified performance is obtained. The substrate with qualified performance is fully inspected in terms of size and appearance to confirm that it meets the product specification requirements and obtain a finished three-dimensional circuit.

[0088] Specifically, prepare a passivation treatment solution. The selection of the passivation treatment solution is directly related to the corrosion resistance and long-term performance of the circuit substrate. The use of a special copper protection passivation solution can meet the 96-hour neutral salt spray test. When the neutral salt spray test requirements of more than 96 hours are to be met, a 100% concentration of passivation solution should be used as the passivation solution for treatment. The concentration C of the passivation solution is expressed as the solute mass m sRatio to the total volume V of the solution: In this process, the passivation solution does not need to be diluted, and its concentration is set to 1 (i.e. 100%) to ensure that it forms a dense and stable protective layer on the metal surface. The temperature of the passivation solution is adjusted to 25-35°C, which is the optimal temperature range for the passivation reaction, which helps to increase the chemical reaction rate and ensure the uniformity of the protective film. The adjustment formula for temperature T is T = T i +ΔT, where T i is the initial temperature, and ΔT is the temperature difference that needs to be increased or decreased. Through a precise temperature control device (such as a constant temperature water bath or a heating plate), the temperature stability of the passivation solution is maintained to avoid uneven passivation effect due to temperature fluctuations, and a passivation solution with a constant temperature is obtained. The three-dimensional circuit substrate with thickened coating is immersed in a passivation solution with a constant temperature. The immersion time is strictly controlled within the range of 1-10 minutes to ensure that the protective layer can completely cover the surface of the substrate. The efficiency of the passivation reaction is expressed by the rate formula R=k·[C]·A, where R is the passivation rate, k is the reaction rate constant, [C] is the passivation solution concentration, and A is the surface area of ​​the substrate. By controlling the immersion time t, a passivation film composed of oxides or chemical complexes is uniformly formed on the surface of the metal coating to obtain a passivated circuit substrate. After the immersion is completed, the substrate is removed from the passivation solution and its surface is cleaned to remove the residual passivation solution. The key to the cleaning process is the water flow rate Q, which is calculated by the formula Q=v·A, where v is the water flow rate and A is the cross-sectional area of ​​the cleaning nozzle. The cleaning process can ensure the purity of the passivation layer, avoid the influence of residual liquid on the performance of the substrate, and obtain a passivation substrate with a clean surface. After the cleaning is completed, the substrate is dried with hot air to ensure that there is no residual moisture on its surface. The drying temperature is set within the seventh preset range, and the specific value depends on the heat resistance of the substrate and the chemical stability of the passivation film. Temperature T h Controlled at 60-80℃, drying time t h The optimization is based on the surface area and thickness of the substrate. The clean surface of the passivated substrate is thoroughly dried by hot air drying equipment to obtain a dry passivated substrate. The dry passivated substrate is placed in a neutral salt spray test chamber for corrosion resistance testing. During the test, the concentration of the salt spray is C s Usually 5% sodium chloride solution, spray pressure P s About 70-120kPa, test temperature T s The temperature is set to 35℃. The test time is not less than 48 hours. By observing the corrosion of the substrate surface, the salt spray resistance is evaluated to see whether it meets the standard. If there is no obvious corrosion on the substrate surface after the test, it is judged to be a substrate with qualified corrosion resistance. After the salt spray test is passed, the welding performance of the substrate is tested. The welding performance test is performed by measuring the pull-out force F of the solder joint. w , the formula is F w =σ·A w, where σ is the shear strength of the solder joint, A w is the area of ​​the solder joint. Only when the welding performance meets the mechanical strength requirements can the substrate be judged as a substrate with qualified performance. To ensure the consistency and appearance quality of the finished product, the substrate with qualified performance is fully inspected in terms of size and appearance. The size inspection is completed by an imager, and the deviation Δ is calculated as Δ=L m -L d |, where L m is the actual measured value, L d The design value. The appearance inspection is carried out visually to ensure that there are no scratches, dents or other defects on the substrate surface. After comprehensive inspection, the finished three-dimensional circuit substrate that meets the product specification requirements is finally obtained.

[0089] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for implementing a three-dimensional circuit manufacturing process, characterized in that: The method comprises: S1. Substrate preparation steps: When making circuits on the surface of a metal substrate, the surface of the metal substrate must first be coated with insulating material; plastic carriers are produced by injection molding, and ceramic products are produced by die casting and sintering processes; S2, surface shielding step: when the area of ​​the non-circuit region exceeds a threshold, a shielding fixture is used to shield the non-circuit region to obtain a partially shielded substrate; S3, vacuum sputtering step: placing the substrate in a vacuum sputtering chamber, firstly performing plasma cleaning and roughening on the surface of the substrate, and then performing cathode sputtering to deposit the target metal on the exposed surface of the substrate to obtain a metal-plated substrate; S4, laser circuit forming step: performing laser forming processing on the surface of the metal-plated substrate to obtain a formed three-dimensional circuit substrate; S5, coating thickening step: when the coating thickness of vacuum sputtering does not meet the design requirements, the three-dimensional circuit substrate after laser forming is thickened by chemical plating or electroplating to obtain a three-dimensional circuit substrate with thickened coating; S6, surface passivation treatment step: using a passivation solution to perform passivation protection treatment on the coating surface of the three-dimensional circuit substrate to obtain a finished three-dimensional circuit.

2. The method for implementing the three-dimensional circuit manufacturing process according to claim 1, characterized in that: Step S1 includes: Selecting a metal conductor substrate, a plastic substrate or a ceramic substrate as the substrate to be processed; When the metal conductor substrate is selected, an insulating material is coated on the surface of the metal conductor substrate; when the plastic substrate is selected, an injection molding process is adopted for preparation; when the ceramic substrate is selected, a die casting and sintering process is adopted for preparation.

3. The method for implementing the three-dimensional circuit manufacturing process according to claim 2, characterized in that: Step S2 includes: Determine the position and area of ​​the non-circuit area on the substrate surface, and perform masking when the area exceeds a threshold; Designing a plastic shielding fixture according to the position and graphic pattern of the shielding area, the plastic shielding fixture includes an integral structure for shielding a large area and a split structure for shielding a local area; The plastic shielding fixture is manufactured by injection molding process, and the material of the plastic shielding fixture is selected from low-cost plastic material to obtain a molded shielding fixture; A buckle-type structure is provided on the molded shielding fixture, wherein the buckle-type structure matches the substrate to obtain a shielding fixture with a buckle; Installing the shielding fixture with buckles on the non-circuit area of ​​the substrate and fixing the connection through the buckle structure to obtain a preliminarily shielded substrate; Detecting the installation tightness of the masking fixture on the preliminary masked substrate to ensure that the masking fixture fits the surface of the substrate without any gap, so as to obtain a sealed and masked substrate; The sealed and shielded substrate is visually inspected to confirm the integrity and accuracy of the shielded area, thereby obtaining a partially shielded substrate that passes the inspection.

4. The method for implementing the three-dimensional circuit manufacturing process according to claim 3, characterized in that: Step S3 includes: Placing the substrate in a vacuum chamber, and pumping the air pressure in the vacuum chamber to a preset vacuum degree to obtain a substrate in a vacuum environment; Introducing an inert gas into the vacuum chamber where the substrate is located in the vacuum environment, controlling the gas pressure within a third preset range, and obtaining a gas environment to be discharged; Performing gas discharge in the gas environment to be discharged to generate plasma, and obtaining a stable plasma environment by controlling the discharge power; The surface of the substrate is subjected to ion bombardment treatment in the plasma environment to remove surface pollutants while increasing the surface energy and roughness of the substrate and improving the adhesion of the coating; Select copper, nickel or aluminum as a target material, and perform cathode sputtering in the plasma environment to obtain metal atoms to be deposited; The metal atoms to be deposited are deposited on the surface of the substrate to form a film; when the thickness of the finished circuit is required to be no more than 10 microns, direct sputtering to the specified thickness can be considered; if chemical plating or electroplating is selected to thicken the metal coating, the thickness of the vacuum sputtered coating is controlled within the range of 0.1-1 microns during vacuum sputtering to obtain a preliminary coating substrate; if chemical plating or electroplating is used to thicken the vacuum sputtered coating, the vacuum sputtered coating is selected to be sputtered copper or sputtered nickel, and these two metals are more suitable for subsequent chemical plating or electroplating thickening treatment; The coating thickness uniformity and adhesion of the coating substrate are tested to ensure that the test results meet the specified standards. If the test results do not meet the standard requirements, the process parameters of the vacuum sputtering need to be optimized until the requirements are met. The vacuum sputtered coating substrate is removed from the vacuum chamber to obtain a metal coating substrate.

5. The three-dimensional circuit manufacturing process implementation method according to claim 4, characterized in that: Step S4 includes: If a masking fixture is used on the surface of the vacuum sputtered substrate, first remove the masking fixture on the metal-plated substrate to keep the substrate surface coating intact, obtain the metal-plated substrate to be processed, and load the metal-plated substrate to be processed into the three-dimensional laser forming equipment, import the design pattern and generate the laser processing path to obtain the processing program; Setting laser processing parameters according to the processing program, including controlling the laser power within a fourth preset range, the scanning speed within a fifth preset range, and the spot spacing and the filling spacing within a sixth preset range, to obtain laser processing parameter settings; When the metal-plated substrate to be processed is a plastic substrate and there is no subsequent chemical plating or electroplating process, the light transmittance ratio of the plastic substrate is detected to confirm that the light transmittance ratio is not less than 10%; if the light transmittance is poor, it is necessary to adjust the added components and proportions of the plastic particles during injection molding to prevent significant damage to the plastic during laser molding; According to the processing procedure and the laser processing parameter settings, the metal layer on the surface of the substrate is laser cut, the metal layer in the circuit area is retained, and the metal layer in the non-circuit area is removed to obtain a preliminarily cut circuit substrate; Detecting the circuit size and edge profile of the initially cut circuit substrate to ensure that the design tolerance requirements are met and a qualified circuit substrate is obtained; The surface of the circuit substrate that has passed the inspection is cleaned to remove the residues produced by laser cutting to obtain a circuit substrate with a clean surface, and the conductivity of the circuit substrate with a clean surface is tested to ensure that the circuit pattern is complete without open circuits to obtain a formed three-dimensional circuit substrate.

6. The method for implementing the three-dimensional circuit manufacturing process according to claim 5, characterized in that: Step S5 includes: The conductivity of the coating surface of the formed three-dimensional circuit substrate is detected to ensure that the circuit conductivity requirements are met, there is no short circuit problem or the coating thickness is lower than the thickness requirement, and a circuit substrate with qualified conductivity is obtained; when the vacuum sputtering coating cannot meet the thickness requirements and needs to be thickened by chemical plating or electroplating, the following steps are followed: Prepare a chemical copper plating solution, control the concentration of copper sulfate to 15-20 g / L, the concentration of reducing agent formaldehyde to 15-20 ml / L, the concentration of complexing agent EDTA-2Na to 30-40 g / L, and adjust the pH value to 12-13 to obtain a chemical copper plating solution; preparing a copper electroplating solution, controlling the content of copper sulfate to be 150-250 g / L and the content of sulfuric acid to be 50-70 g / L, to obtain a copper electroplating solution; When the chemical copper plating process is adopted, the circuit substrate with qualified conductivity is immersed in the chemical copper plating solution, the solution temperature is controlled within the range of 30-45° C., and the stirring speed of the plating solution is controlled to obtain the circuit substrate with chemical copper plating; When the copper electroplating process is adopted, the circuit substrate with qualified conductivity is used as the cathode and the pure copper plate is used as the anode in the copper electroplating solution, and the current density is controlled at 1-5A / dm 2 Within the range, a circuit substrate of electroplated copper is obtained; Measuring the coating thickness of the chemically copper-plated circuit substrate or the electrolytic copper-plated circuit substrate to ensure that the design specifications are met and a circuit substrate with a qualified thickness is obtained; The surface of the circuit substrate with a qualified thickness is cleaned to remove the residual chemical copper plating solution or electrolytic copper plating solution to obtain a circuit substrate with a clean surface.

7. The method for implementing the three-dimensional circuit manufacturing process according to claim 6, characterized in that: Step S6 includes: Prepare a passivation treatment solution. When it is necessary to pass a 96-hour neutral salt spray test, use a 100% concentration of passivation solution to obtain a passivation solution for treatment; The temperature of the treatment passivation solution is adjusted to a range of 25-35° C. and the temperature is kept stable to obtain a passivation solution with a constant temperature; Immersing the three-dimensional circuit substrate with thickened coating into the passivation solution with constant temperature, controlling the immersion time within the range of 1-10 minutes, to obtain a passivated circuit substrate; The passivated circuit substrate is taken out from the passivation solution, the surface is cleaned, and the residual passivation solution is removed to obtain a passivated substrate with a clean surface; Drying the cleaned passivation substrate with hot air, controlling the drying temperature within a seventh preset range, to obtain a dry passivation substrate; The corrosion resistance and welding performance of the coating on the surface of the passivated substrate are tested to ensure that the design standards are met and a substrate with qualified performance is obtained. The substrate with qualified performance is fully inspected for appearance to confirm that the product appearance meets the product specification requirements and a finished three-dimensional circuit is obtained.

8. A three-dimensional circuit manufacturing process realization device, characterized in that: Used to execute the three-dimensional circuit manufacturing process implementation method as described in any one of claims 1-7.

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