Circuit board preparation method and circuit board

Abstract

The invention discloses a circuit board preparation method and a circuit board, and the method comprises the steps: presetting a shielding protection plate in a conductive circuit region on the surface of the circuit board; preparing an insulating layer in an area, where the shielding protection plate is not preset, of the circuit board through a surface coating; removing a shielding protection plate preset on the surface of the circuit board; and preparing a conductive circuit layer in the area, where the preset shielding protection plate is removed, of the circuit board through a surface coating. The bonding force between the insulating layer and the conductive circuit layer and the circuit board substrate is high, the insulating layer and the conductive circuit layer of the prepared circuit board are excellent in performance, the preparation cost is lower, and the service cycle is longer.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board processing, and in particular to a circuit board preparation method and a circuit board. Background Art

[0002] With the rapid development of electronic technology, electronic equipment is becoming increasingly miniaturized and high-performance. The precise preparation of the insulating layer and conductive circuit of the circuit board has become a key research direction. However, the traditional lamination, coating, printing and etching methods have many shortcomings in the process of preparing the insulating layer and conductive circuit layer of the circuit board. In terms of the insulating layer, the bonding force between the insulating layer prepared by lamination, coating and printing methods and the circuit board substrate is poor. At the same time, conventional organic resins have poor high temperature resistance. Once the circuit board is in the condition of long-term operation of electronic equipment to generate heat accumulation, or near the heat source, the insulating layer will quickly soften, deform and peel off, resulting in rapid deterioration of insulation performance, posing a great hidden danger to circuit safety. Moreover, this type of traditional insulating material has poor chemical corrosion resistance. When it comes into contact with chemical reagents in the production process of the circuit board, or when it encounters corrosive substances such as acids and alkalis in special working environments, it is very easy to be damaged, and long-term stable insulation performance cannot be guaranteed.

[0003] From the perspective of conductive circuit preparation, the traditional etching process has prominent limitations. On the one hand, due to the precision bottleneck of etching equipment and the inherent performance limitations of photoresist, there are many difficulties in the pursuit of ultra-fine circuit production. Faced with the current trend of miniaturization of electronic products, the traditional etching process cannot meet the needs of high-density circuit layout due to the stringent requirements for the width of conductive lines to be less than the micron scale. On the other hand, the bonding force between the metal conductive circuit layer and the insulating layer prepared by the traditional etching process is relatively weak. When the circuit board is subjected to external forces commonly seen in actual use, such as thermal cycles and vibrations, the conductive circuit is very prone to falling off and circuit failures, which seriously affect the reliability and service life of the circuit board.

[0004] At present, the commercial use of 5G requires circuit boards to have excellent electrical performance and low signal loss; the demand for IoT devices drives them to develop towards miniaturization and multi-function; the rise of the electric vehicle industry requires circuit boards to have high temperature resistance and high reliability. Therefore, the preparation of circuit board insulation layers and conductive lines with good performance and reliable structure is an urgent problem to be solved by personnel in this technical field.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] The present invention provides a method for preparing a circuit board and a circuit board, which effectively solve the problems that the bonding force between the insulating layer and the conductive circuit layer prepared by the traditional process and the circuit board substrate is weak, the conductive circuit is easy to fall off from the circuit board substrate, and the conductive circuits are broken.

[0007] A method for preparing a circuit board includes: A shielding protection plate is pre-placed in the conductive circuit area on the surface of the circuit board; preparing an insulating layer by surface coating in an area of ​​the circuit board where no shielding protection plate is pre-set; Remove the shielding protection plate pre-installed on the surface of the circuit board; A conductive circuit layer is prepared by surface coating in the area of ​​the circuit board where the pre-set shielding protection plate is removed.

[0008] In the circuit board preparation method, the substrate of the circuit board includes resin, metal and ceramic.

[0009] In the circuit board preparation method, before preparing the insulating layer or the conductive circuit layer by surface coating, the circuit board is subjected to surface pretreatment to remove grease, dirt and oxide film on the surface of the circuit board. The surface pretreatment includes sandblasting, pickling, phosphating, etching, polishing, ultrasonic and grinding.

[0010] In the circuit board preparation method described above, the shape and size of the shielding protection plate are the same as those of the conductive circuit, and the material of the shielding protection plate includes metal, ceramic and polymer material; the shielding protection plate is mechanically connected and fixed to the circuit board substrate, and after the insulating layer is prepared, the shielding protection plate can be removed.

[0011] In the circuit board preparation method, the materials used to prepare the insulating layer include plastic, rubber, ceramics and grease; the materials used to prepare the conductive circuit layer include metal, polymer material and ceramics, and the metal includes alloy and composite metal.

[0012] In the circuit board preparation method, the surface coating includes a coating prepared by spraying, electroplating, chemical plating, brush plating, physical vapor deposition and chemical vapor deposition processes.

[0013] In the circuit board preparation method, a spraying process is adopted, and the insulating layer and the conductive circuit layer are prepared by the automatic control of the fixed spray gun by the manipulator during the spraying process, so as to realize the preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The spraying process parameters include spraying power 1-200kW, spraying distance 10-500mm, spray gun movement speed controlled by the manipulator 1-2000mm / s, repeat positioning accuracy controlled by the manipulator 0.01mm-1mm, step length of spray gun movement controlled by the manipulator 0.1-10mm, powder feeding rate 1-200g / min, powder feeding pressure 0.1-20MPa; an electroplating process is adopted, and the insulating layer and the conductive circuit layer are prepared by the electroplating automatically controlled by the digital display system during the electroplating process, so as to realize the preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The parameters include current density 0-6ASD (A / dm 2 ), temperature 10-70℃, time 1-30min, plating solution concentration 1-200g / L.

[0014] In the circuit board preparation method, the insulation voltage range of the insulation layer is 0-220V, and the insulation current density range of the insulation layer is 0-200ASD (A / dm 2 ), the conductivity of the conductive circuit layer is 0-100% IACS.

[0015] In the circuit board preparation method, the thickness of the insulating layer and the conductive circuit layer is 0-200 mm, and the bonding strength between the insulating layer and the conductive circuit layer and the circuit board substrate is 1-300 MPa.

[0016] A circuit board is prepared by the method.

[0017] Compared with the prior art, the present invention has the following advantages: the present invention pre-sets a shielding protection plate on the conductive circuit area on the surface of the circuit board, and prepares an insulating layer in the area of ​​the circuit board where the shielding protection plate is not pre-set by surface coating; then removes the shielding protection plate pre-set on the surface of the circuit board, and prepares a conductive circuit layer by surface coating in the area where the pre-set shielding protection plate is removed; the preparation method can prevent the weak bonding between the metal conductive circuit, the insulating layer and the circuit board substrate, the conductive circuit easily falling off the circuit board substrate, and the occurrence of short circuits between the conductive circuits, thereby improving the reliability and stability of the performance of the insulating layer and the conductive circuit layer of the circuit board. Compared with the traditional preparation process, the cost of the prepared insulating layer and the conductive circuit layer of the circuit board is reduced by 10%-90% times, and the service life is increased by 1-5 times. The present invention provides an effective solution for the preparation of the insulating layer and the conductive circuit layer of the circuit board. The synergistic guarantee technical effects of the preparation process of the insulating layer and the conductive circuit layer in the present invention include: Automatic control by manipulator or digital display system can realize accurate preparation of conductive circuit layer and insulating layer. The use of the shielding protection plate ensures that the conductive line area is not covered by the insulating layer, thereby achieving accurate conductive line preparation. After removing the shielding protection plate, the conductive line layer is prepared by surface coating to ensure the accurate position of the conductive line.

[0018] Enhance bonding strength Surface pretreatment removes impurities on the surface of the circuit board and improves the bonding strength between the insulating layer and the conductive circuit layer and the substrate. At the same time, the application of surface coating further enhances this bonding force and reduces circuit shedding and circuit breakage caused by weak bonding force.

[0019] Improved resistance to high temperatures and chemical corrosion The insulation layer is made of high-performance materials to ensure excellent resistance to high temperatures and chemical corrosion, ensuring that the circuit board can still operate stably in harsh environments.

[0020] Optimizing process parameters By adjusting the process parameters such as spraying and electroplating, the quality, thickness, size and pattern of the coating can be precisely controlled to ensure that the performance of the insulating layer and the conductive circuit layer is optimal. This not only improves the preparation efficiency, but also ensures the consistency of product quality.

[0021] The circuit board preparation method of the present invention solves many problems in traditional processes through the synergistic effects of the shielding protection plate, surface pretreatment, insulation layer and conductive circuit layer. Specifically, the shielding protection plate ensures the precise positioning of the conductive circuit; the surface pretreatment improves the bonding strength; and the high-quality preparation of the insulation layer and the conductive circuit layer enhances the reliability and service life of the circuit board. These designs work together to ensure the efficient operation and long life of the circuit board prepared by the present invention under complex working conditions. Compared with traditional preparation processes, the present invention significantly improves the performance and service life of the circuit board and significantly reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0023] In the attached picture: Figure 1 This is a scanning electron microscope image of an insulating layer prepared on the surface of a circuit board substrate in a preferred embodiment of the present invention; Figure 2 This is a topographical diagram of a circuit board shielding protection zone and an insulating layer in a preferred embodiment of the present invention; Figure 3 This is a topographical diagram of a circuit board conductive circuit and an insulating layer of a preferred embodiment of the present invention; Figure 4 is a schematic cross-sectional view of a conductive circuit and an insulating layer structure of a circuit board according to an embodiment of the present invention; Figure 5 is a top view of a conductive circuit board and an insulating layer of an embodiment of the present invention; Figure 6 1 is a schematic diagram comparing the performance and cost of the insulating layer and the conductive circuit layer prepared by the preferred embodiment of the present invention and the conventional coating process (in the figure, the horizontal axis 0 represents the conventional coating process, and the horizontal axes 1-6 represent implementation cases 1-6 respectively); Figure 7 It is a schematic diagram comparing the service life of the insulating layer and the conductive circuit layer prepared by the preferred embodiment of the present invention and the traditional coating process (in the figure, the horizontal axis 0 represents the traditional coating process, and the horizontal axes 1-6 are implementation cases 1-6 respectively).

[0024] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0026] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0027] To facilitate understanding of the embodiments of the present invention, further explanation will be given below by taking specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0028] like Figures 1 to 7 As shown, the circuit board preparation method includes the following steps: A shielding protection plate is pre-placed in the conductive circuit area on the surface of the circuit board; preparing an insulating layer by surface coating in an area of ​​the circuit board where no shielding protection plate is pre-set; Remove the shielding protection plate pre-installed on the surface of the circuit board; A conductive circuit layer is prepared by surface coating in the area of ​​the circuit board where the pre-set shielding protection plate is removed.

[0029] In a preferred embodiment of the circuit board preparation method, the substrate of the circuit board includes resin, metal and ceramic.

[0030] In a preferred embodiment of the circuit board preparation method, before preparing the insulating layer or the conductive circuit layer by surface coating, the circuit board is subjected to surface pretreatment to remove grease, dirt and oxide film on the surface of the circuit board, and the surface pretreatment includes sandblasting, pickling, phosphating, etching, polishing, ultrasonic and grinding.

[0031] In a preferred embodiment of the circuit board preparation method, the shape and size of the shielding protection plate are the same as the shape and size of the conductive circuit, and the material of the shielding protection plate includes metal, ceramic and polymer material; the shielding protection plate is mechanically connected and fixed to the circuit board substrate, and the shielding protection plate can be removable and removed after the insulating layer is prepared.

[0032] In a preferred embodiment of the circuit board preparation method, the materials used to prepare the insulating layer include plastic, rubber, ceramics and grease; the materials used to prepare the conductive circuit layer include metals, polymer materials and ceramics, and the metals include alloys and composite metals.

[0033] In a preferred embodiment of the circuit board preparation method, the surface coating includes a coating prepared by spraying, electroplating, chemical plating, brush plating, physical vapor deposition and chemical vapor deposition processes.

[0034] In a preferred embodiment of the circuit board preparation method, a spraying process is adopted, and during the spraying process, a fixed spray gun is automatically controlled by a manipulator to prepare an insulating layer and a conductive circuit layer, so as to achieve the preparation of the thickness, size and pattern of the conductive circuit and the insulating layer. The spraying process parameters include a spraying power of 1-200kW, a spraying distance of 10-500mm, a spray gun movement speed controlled by the manipulator of 1-2000mm / s, a repeat positioning accuracy controlled by the manipulator of 0.01mm-1mm, a step length of the spray gun movement controlled by the manipulator of 0.1-10mm, a powder feeding rate of 1-200g / min, and a powder feeding pressure of 0.1-20MPa; an electroplating process is adopted, and during the electroplating process, an insulating layer and a conductive circuit layer are prepared by electroplating automatically controlled by a digital display system, so as to achieve the preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The parameters include a current density of 0-6ASD (A / dm 2 ), temperature 10-70℃, time 1-30min, plating solution concentration 1-200g / L.

[0035] In a preferred embodiment of the circuit board manufacturing method, the insulation voltage range of the insulation layer is 0-220V, and the insulation current density range of the insulation layer is 0-200ASD (A / dm 2 ), the conductivity of the conductive circuit layer is 0-100% IACS.

[0036] In a preferred embodiment of the circuit board preparation method, the thickness of the insulating layer and the conductive circuit layer is 0-200 mm, and the bonding strength between the insulating layer and the conductive circuit layer and the circuit board substrate is 1-300 MPa.

[0037] A circuit board is prepared by the method described. Figures 4 to 5 As shown, the circuit board includes a circuit board substrate 1, in which a shielding protection plate is pre-set in the conductive circuit area on the surface of the circuit board substrate 1; an insulating layer 3, which is prepared by surface coating in the area of ​​the circuit board where the shielding protection plate is not pre-set; and a conductive circuit layer 2, which is prepared by surface coating in the area of ​​the circuit board substrate 1 where the pre-shielding protection plate is removed.

[0038] In one embodiment, the preparation method comprises the following steps: The insulating layer of the circuit board is prepared by pre-setting a shielding protection plate in the conductive circuit area on the surface of the circuit board, and preparing an insulating layer in the area of ​​the circuit board where the shielding protection plate is not pre-set by surface coating; then the shielding protection plate pre-set on the surface of the circuit board is removed, and the conductive circuit layer is prepared by surface coating in the area where the shielding protection plate is removed; the substrate of the circuit board includes resin, metal and ceramic. Before preparing the insulating layer and the conductive circuit layer by surface coating, the substrate of the circuit board is subjected to surface pretreatment to remove grease, dirt and oxide film on the surface of the circuit board, and the surface pretreatment methods include: sandblasting, pickling, phosphating, etching, polishing, ultrasonic and grinding. The shape and size of the shielding protection plate are the same as those of the conductive circuit, and the material of the shielding protection plate includes metal, ceramic and polymer material; the shielding protection plate and the substrate of the circuit board are mechanically connected and fixed, and the shielding protection plate can be removed after the insulating layer is prepared. The materials for preparing the insulating layer include plastic, rubber, ceramic and grease; the materials for preparing the conductive circuit layer include metal, alloy and composite metal, polymer material and ceramic. The insulating layer and the conductive layer are prepared by surface coating, which includes coatings prepared by spraying, electroplating, chemical plating, brush plating, physical vapor deposition and chemical vapor deposition processes. The thickness of the insulating layer and the conductive layer is 0-200mm, and the bonding strength between the insulating layer and the conductive layer and the circuit board substrate is 1-300MPa. The insulation voltage range of the insulating layer is 0-220V, and the insulation current density range of the insulating layer is 0-200ASD (A / dm 2 ), the conductivity of the conductive circuit layer is 0-100% IACS.

[0039] In a preferred embodiment of the method, a spraying process is adopted, and during the spraying process, a fixed spray gun is automatically controlled by a manipulator to prepare an insulating layer and a conductive circuit layer, so as to achieve accurate preparation of the thickness, size and pattern of the conductive circuit and the insulating layer, and the spraying process parameters include: spraying power 1-200kW, spraying distance 10-500mm, spray gun movement speed controlled by the manipulator is 1-2000mm / s, repeat positioning accuracy controlled by the manipulator is 0.01mm-1mm, step length of spray gun movement controlled by the manipulator is 0.1-10mm, powder feeding rate is 1-200g / min, and powder feeding pressure is 0.1-20MPa.

[0040] In the preferred embodiment of the method, the insulating layer and the conductive circuit layer are prepared by electroplating automatically controlled by a digital display system during the electroplating process, so as to achieve accurate preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The parameters include: current density 0-6ASD (A / dm 2 ), temperature 10-70℃, time 1-30min, plating solution concentration 1-200g / L.

[0041] Example 1 Phenolic resin is used as a circuit substrate, a shielding copper-based protective plate is pre-set on the conductive circuit area on the surface of the phenolic resin substrate, the shape and size of the shielding protective plate are the same as the shape and size of the conductive circuit, the shielding protective plate and the circuit board substrate are mechanically riveted and fixed, and a polytetrafluoroethylene insulation layer (such as Figure 1 to Figure 2 As shown). The insulating layer and the conductive circuit layer are prepared by a spraying method automatically controlled by a robot. During the spraying process, the thickness, size and pattern of the conductive circuit and the insulating layer are accurately prepared through the automatic control of the robot-fixed spray gun. The spraying process parameters include: spraying power 40kW, spraying distance 100mm, robot-controlled spray gun movement speed 400mm / s, robot-controlled repeat positioning accuracy 0.01, robot-controlled spray gun movement step length 1mm, powder feeding rate 50g / min, powder feeding pressure 20MPa, polytetrafluoroethylene curing temperature 380℃, curing time 0.5 hour. Subsequently, the shielding protection plate pre-installed on the surface of the circuit board is removed, and the conductive circuit layer is prepared by electroplating process in the area where the pre-installed shielding protection plate is removed. The material of the conductive circuit layer is pure copper (such as Figure 3 The electroplating process is controlled by the digital display system to automatically control the preparation of the insulating layer and the conductive circuit layer, so as to achieve the accurate preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The process parameters of the electroplated copper conductive layer include: cuprous chloride 20g / L, sodium cyanide 35g / L, sodium hydroxide 5g / L, pH 10, temperature 40℃, current density 1ASD (A / dm 2 ), time 3min. The thickness of the prepared insulating layer is 2mm, and the bonding strength between the insulating layer and the substrate is 100MPa. The insulating layer can insulate a voltage of 36V and a current density of 40ASD (A / dm 2 ). Compared with the traditional preparation process, the cost of the prepared circuit board insulation layer and conductive circuit layer is reduced by 60%, and the service life is increased by 3 times.

[0042] Example 2 Epoxy resin is used as the circuit substrate, and a shielding stainless steel-based protective plate is pre-set on the conductive circuit area on the surface of the epoxy resin substrate. The shape and size of the shielding protective plate are the same as those of the conductive circuit. The shielding protective plate and the circuit board substrate are mechanically riveted and fixed (such as Figures 4 to 5As shown in the figure, an aluminum oxide insulating layer is prepared in an area where a shielding protection plate is not preset by a flame spraying process. The insulating layer and the conductive circuit layer are prepared by a spraying method automatically controlled by a manipulator. During the spraying process, the thickness, size and pattern of the conductive circuit and the insulating layer are accurately prepared by the automatic control of the manipulator fixing the spray gun. The spraying process parameters include: oxygen pressure 0.5MPa, acetylene pressure 0.08MPa, spraying distance 200mm, the movement speed of the spray gun controlled by the manipulator is 200mm / s, the repeat positioning accuracy controlled by the manipulator is 0.02, the step length of the spray gun controlled by the manipulator is 2mm, the powder feeding rate is 100g / min, and the powder feeding pressure is 10MPa. Subsequently, the shielding protection plate preset on the surface of the circuit board is removed, and the conductive circuit layer is prepared by an electroplating process in the area where the preset shielding protection plate is removed. The material of the conductive circuit layer is pure silver. During the electroplating process, the insulating layer and the conductive circuit layer are prepared by the electroplating automatically controlled by the digital display system, so as to realize the accurate preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The process parameters of the electroplated silver conductive layer include: silver chloride 20g / L, potassium cyanide 100g / L, potassium hydroxide 6g / L, pH 10, temperature 25℃, current density 0.5ASD (A / dm 2 ), time 2min. The thickness of the insulating layer is 3mm, and the bonding strength between the insulating layer and the substrate is 150MPa. The voltage that the insulating layer can insulate is 50V, and the current density that the insulating layer can insulate is 50ASD (A / dm 2 ). Compared with the traditional preparation process, the cost of the prepared circuit board insulation layer and conductive line layer is reduced by 40%, and the service life is doubled.

[0043] Example 3 Copper alloy is used as the circuit substrate, and a shielded aluminum nitride-based protective plate is pre-set in the conductive circuit area on the surface of the copper alloy substrate. The shape and size of the shielding protective plate are the same as those of the conductive circuit. The shielding protective plate and the circuit board substrate are fixed by mechanical bolts, and a silicon carbide insulating layer is prepared in the area where the shielding protective plate is not pre-set by chemical vapor deposition. The parameters of the chemical vapor deposition process used include: deposition power 20kW, silicon tetrachloride flow 1L / min, methane 5L / min, heating temperature 1200℃, reaction time 20min. Subsequently, the shielding protective plate pre-set on the surface of the circuit board is removed, and a conductive circuit layer is prepared by electroplating in the area where the pre-set shielding protective plate is removed. The material of the conductive circuit layer is pure nickel. During the electroplating process, the insulating layer and the conductive circuit layer are prepared by the electroplating automatically controlled by the digital display system, so as to achieve the accurate preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The process parameters of the electroplated nickel conductive layer include: nickel sulfate 260g / L, nickel cyanide 45g / L, boric acid 40g / L, potassium hydroxide 6g / L, pH value 4, temperature 55℃, current density 4ASD (A / dm 2), time 2min. The thickness of the insulating layer is 5mm, and the bonding strength between the insulating layer and the substrate is 120MPa. The voltage that the insulating layer can insulate is 100V, and the current density that the insulating layer can insulate is 60ASD (A / dm 2 ). Compared with the traditional preparation process, the cost of the prepared circuit board insulation layer and conductive circuit layer is reduced by 50%. The service life is increased by 1.5 times.

[0044] Example 4 Stainless steel is used as the circuit substrate, and a shielded silica-based protective plate is pre-set in the conductive circuit area on the surface of the stainless steel substrate. The shape and size of the shielding protective plate are the same as those of the conductive circuit. The shielding protective plate and the circuit board substrate are fixed by mechanical bolts. The epoxy resin insulation layer is prepared in the area where the shielding protective plate is not pre-set by electrostatic spraying. The insulation layer and the conductive circuit layer are prepared by a spraying method automatically controlled by a manipulator. During the spraying process, the thickness, size and pattern of the conductive circuit and the insulation layer are accurately prepared by the automatic control of the manipulator fixed spray gun. The spraying process parameters include: spraying power of 10kW, spraying distance of 200mm, repeat positioning accuracy of manipulator control of 0.02mm, step length of the spray gun controlled by manipulator control of 2mm, spray gun movement speed controlled by manipulator control of 400mm / s, powder feeding rate of 50g / min, powder feeding pressure of 10MPa, epoxy resin curing temperature of 350℃, curing time of 1 hour. Then, the shielding protection plate pre-installed on the surface of the circuit board is removed, and a conductive circuit layer is prepared by physical vapor deposition process in the area where the pre-installed shielding protection plate is removed. The material of the conductive circuit layer is platinum. The parameters of the physical phase deposition process used include: deposition power 40kW, target material is pure platinum, heating temperature 2000℃, reaction time 10min. The thickness of the insulating layer is 20mm, and the bonding strength between the insulating layer and the substrate is 200MPa. The voltage that the insulating layer can insulate is 120V, and the current density that the insulating layer can insulate is 80ASD (A / dm 2 ). Compared with the traditional preparation process, the cost of the prepared circuit board insulation layer and conductive circuit layer is reduced by 60%, and the service life is doubled.

[0045] Example 5 Alumina is used as the circuit substrate, and a shielding stainless steel-based protective plate is pre-set in the conductive circuit area on the surface of the alumina substrate. The shape and size of the shielding protective plate are the same as those of the conductive circuit. The shielding protective plate and the circuit board substrate are fixed by mechanical bolts, and an aluminum nitride insulating layer is prepared in the area where the shielding protective plate is not pre-set by a chemical vapor deposition process. The parameters of the chemical vapor deposition process used include: deposition power 30kW, aluminum chloride flow 2L / min, nitrogen 10L / min, heating temperature 1500℃, and reaction time 30min. Subsequently, the shielding protective plate pre-set on the surface of the circuit board is removed, and a conductive circuit layer is prepared by a cold spraying process in the area where the pre-set shielding protective plate is removed. The material of the conductive circuit layer is pure aluminum. The insulating layer and the conductive circuit layer are prepared by spraying with automatic control of the robot. During the spraying process, the thickness, size and pattern of the conductive circuit and the insulating layer are accurately prepared by the automatic control of the robot fixed spray gun. The spraying parameters include: spraying power of 40kW, spraying distance of 40mm, movement speed of the spray gun controlled by the robot is 500mm / s, powder feeding rate is 40g / min, powder feeding pressure is 5MPa, and heating temperature is 450℃. The thickness of the insulating layer is 30mm, and the bonding strength between the insulating layer and the substrate is 300MPa. The voltage that the insulating layer can insulate is 220V, and the current density that the insulating layer can insulate is 150ASD (A / dm 2 ). Compared with the traditional preparation process, the cost of the prepared circuit board insulation layer and conductive circuit layer is reduced by 80%, and the service life is increased by 4 times.

[0046] Example 6 Aluminum nitride is used as the circuit substrate, and a shielding alumina-based protective plate is pre-set in the conductive circuit area on the surface of the aluminum nitride substrate. The shape and size of the shielding protective plate are the same as those of the conductive circuit. The shielding protective plate and the circuit board substrate are fixed by mechanical bolts. A silicon nitride insulating layer is prepared in the area where the shielding protective plate is not pre-set by a chemical vapor deposition process. The parameters of the chemical vapor deposition process used include: deposition power 40kW, silicon tetrachloride flow 3L / min, nitrogen 10L / min, heating temperature 1400℃, and reaction time 30min. Subsequently, the shielding protective plate pre-set on the surface of the circuit board is removed, and a conductive circuit layer is prepared by an electroplating process in the area where the pre-set shielding protective plate is removed. The material of the conductive circuit layer is pure zinc. During the electroplating process, the insulating layer and the conductive circuit layer are prepared by the electroplating automatically controlled by the digital display system, so as to achieve the accurate preparation of the thickness, size and pattern of the conductive circuit layer and the insulating layer. The process parameters of the electroplated zinc conductive layer include: zinc chloride 70g / L, potassium chloride 200g / L, boric acid 35g / L, pH 5, temperature 50℃, current density 3A / dm 2, time 10min. The thickness of the insulation layer is 50mm, and the bonding strength between the insulation layer and the substrate is 280MPa. The voltage that the insulation layer can insulate is 220V, and the current density that the insulation layer can insulate is 200ASD (A / dm 2 ). Compared with the traditional preparation process, the cost of the prepared circuit board insulation layer and conductive circuit layer is reduced by 80%, and the service life is increased by 2 times.

[0047] See Table 1: Table 1. Performance comparison of the insulating layer and the conductive circuit layer prepared by the preferred embodiment of the present invention and the conventional coating process A method for preparing a circuit board and a circuit board prepared by the method. The preparation method of the present invention can prevent the weak bonding between the metal conductive circuit and the insulating layer, the conductive circuit being prone to falling off from the circuit board substrate, the occurrence of short circuit failures between the conductive circuits, and other problems, thereby improving the reliability and stability of the performance of the insulating layer and the conductive circuit layer of the circuit board. Compared with the traditional preparation process, the cost of the prepared insulating layer and the conductive circuit layer of the circuit board is reduced by 10%-90%, and the service life is increased by 1-5 times. The bonding between the insulating layer and the conductive circuit layer and the circuit board substrate is high, and the prepared insulating layer and the conductive circuit layer of the circuit board have excellent performance, lower preparation cost, and longer service life.

[0048] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields, and the above specific embodiments are only illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can also make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present invention, all of which belong to the protection of the present invention.

Claims

1. A method for preparing a circuit board, characterized in that: The steps include: A shielding protection plate is pre-placed in the conductive circuit area on the surface of the circuit board; preparing an insulating layer by surface coating in an area of ​​the circuit board where no shielding protection plate is pre-set; Remove the shielding protection plate pre-installed on the surface of the circuit board; A conductive circuit layer is prepared by surface coating in the area of ​​the circuit board where the pre-set shielding protection plate is removed.

2. A method for preparing a circuit board according to claim 1, characterized in that: Preferably, the substrate of the circuit board includes resin, metal and ceramic.

3. A method for preparing a circuit board according to claim 1, characterized in that: Before preparing the insulating layer or conductive circuit layer through surface coating, the circuit board is subjected to surface pretreatment to remove grease, dirt and oxide film on the surface of the circuit board. Surface pretreatment includes sandblasting, pickling, phosphating, etching, polishing, ultrasonic and grinding.

4. A method for preparing a circuit board according to claim 1, characterized in that: The materials of the shielding protection plate include metal, ceramic and polymer materials; the shielding protection plate is mechanically connected and fixed to the circuit board substrate, and after the insulating layer is prepared, the shielding protection plate can be disassembled and removed.

5. A method for preparing a circuit board according to claim 1, characterized in that: The materials used to prepare the insulating layer include plastics, rubber, ceramics and grease; the materials used to prepare the conductive circuit layer include metals, polymer materials and ceramics, and the metals include alloys and composite metals.

6. A method for preparing a circuit board according to claim 1, characterized in that: Surface coatings include coatings prepared by spraying, electroplating, chemical plating, brush plating, physical vapor deposition and chemical vapor deposition processes.

7. A method for preparing a circuit board according to claim 1, characterized in that: Using spraying technology.

8. A method for preparing a circuit board according to claim 1, characterized in that: The insulation voltage range of the insulation layer is 0-220V, and the insulation current density range of the insulation layer is 0-200ASD (A / dm 2 ), the conductivity of the conductive circuit layer is 0-100% IACS.

9. A method for preparing a circuit board according to claim 1, characterized in that: The thickness of the insulating layer and the conductive circuit layer is 0-200 mm, and the bonding strength between the insulating layer and the conductive circuit layer and the circuit board substrate is 1-300 MPa.

10. A circuit board, characterized in that: It is prepared by the method according to any one of claims 1 to 9.

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