Production method of post-pressed multilayer high-frequency metal-based carbon oil circuit board

Abstract

The invention discloses a post-pressing multilayer high-frequency metal-based carbon oil circuit board production method, and relates to the field of circuit board production, and the method comprises the steps: carrying out the engineering design, carrying out the pretreatment preparation after the engineering design is completed, and carrying out the hole metallization control of a high-frequency microwave board after the pretreatment preparation is completed. And after hole metallization control of the high-frequency microwave plate is completed, copper plating processing is carried out, and after copper plating processing is completed, metal-based chemical gold plating processing is carried out. According to the post-pressing multilayer high-frequency metal-based carbon oil circuit board production method, a dielectric layer of a multilayer high-frequency metal-based board is generally made of a high-frequency material, a multilayer high-frequency microwave board is firstly manufactured, then pressed together with a metal-based board and then subjected to surface treatment and forming, a carbon oil board is generally used on an FR4 board and is subjected to screen printing through common gauze, the resistance value and thickness error are large, and the resistance value and thickness error are large. And the produced post-pressed high-frequency metal-based carbon oil circuit board is good in heat dissipation and good in signal transmission performance, and the thickness and resistance of the carbon oil meet the requirements of customers.

Description

Technical Field

[0001] The invention relates to the technical field of circuit board production, and in particular to a method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board. Background Art

[0002] Post-pressed multi-layer high-frequency metal-based carbon oil circuit board is a circuit board specially used for high-frequency and high-power electronic equipment, combining the advantages of metal substrate and special materials.

[0003] In the prior art, carbon oil sheets are generally used on FR4 sheets (epoxy resin) and are screen printed with ordinary mesh, resulting in relatively large errors in resistance and thickness.

[0004] In order to overcome the above shortcomings, the Chinese patent of the prior art (Announcement No. CN102159029B) discloses a method for manufacturing a high-frequency aluminum-based circuit board, comprising the following steps: step one, making a photo-painted template; step two, making a cut and a drill; step three, making a surface pattern; step four, making an electroplating and etching; step five, solder mask, character and surface solderability treatment; step six, forming and manufacturing a finished high-frequency aluminum-based circuit board, which not only has high manufacturing precision, effectively improves product quality and work efficiency, but also has stable performance of the obtained high-frequency aluminum-based circuit board; In order to overcome the above shortcomings, the Chinese patent of the prior art (Announcement No. CN103327736B) discloses a high thermal conductivity insulating metal-based printed circuit board, comprising a metal substrate, a metal transition layer formed in sequence by magnetron sputtering, a ceramic layer formed by an arc ion plating method, and a metal conductive layer formed on the ceramic layer; and the thermal conductivity of the ceramic layer is greater than 100W / mK. By depositing the metal transition layer and the high thermal conductivity ceramic layer on the metal substrate, a highly integrated integrated printed circuit board can be formed as a circuit board substrate. The preparation method has easy controllable process parameters, simple steps, stable and reliable product quality, high production efficiency, and low preparation cost.

[0005] Although the existing technology can overcome the above-mentioned deficiencies, there are still other problems in its operation process, such as: the preparation of the post-pressed multi-layer high-frequency metal-based carbon oil circuit board is rather cumbersome, the operation keys are complicated, and it is not conducive to saving operation time. At the same time, the produced post-pressed multi-layer high-frequency metal-based carbon oil circuit board has poor heat dissipation effect and poor signal transmission performance. Summary of the invention

[0006] The purpose of the present invention is to provide a method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board to solve the problem proposed in the above background technology that the preparation of the post-pressed multi-layer high-frequency metal-based carbon oil circuit board is rather cumbersome and the operation keys are complicated, which is not conducive to saving operation time. At the same time, the produced post-pressed multi-layer high-frequency metal-based carbon oil circuit board has poor heat dissipation effect and poor signal transmission performance.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board, S1, engineering design; S2, pretreatment preparation; S3, hole metallization control of the high-frequency microwave board; S4, copper plating processing; S5, metal-based chemical gold plating processing; S6, metal-based machining; S7, pressing of the metal substrate and the high-frequency microwave board; S8, carbon oil control; S9, final inspection and shipment; specifically comprising the following steps: S1, engineering design: when the metal substrate and the high-frequency microwave board are pressed together, the adhesive used The size of the film should be appropriately reduced by 0.2-0.5mm around the shape and the holes and slots to reserve space for the glue to flow out; the circuit film of the high-frequency microwave board will become smaller when the film is compensated due to the corrosion of the liquid medicine, so the film should be appropriately increased; S2, pretreatment preparation: cutting: set the size of the working board according to the equipment process capability and the utilization rate of the board, and then cut the board into the corresponding size; inner layer wet film: according to the data, transfer the graphics to the working board, quality points: line width / distance must be qualified, no exposure is poor ; S3. Hole metallization control of high-frequency microwave board: The material of high-frequency microwave board is generally Teflon or ceramic mixed with FR4, and plasma cleaning is required before chemical copper plating; S4. Copper plating processing: After copper plating, improve the electrical performance requirements; S5. Metal-based chemical gold plating processing: All the liquid tanks are installed with pneumatic vibration, and ultrasonic cleaning is installed in the water washing tank before entering the gold tank to ensure that the liquid in the blind hole is cleaned, and a special gold sinking basket is used. The surface coating of the basket must have a certain elasticity, and there should be no basket marks around the metal base; S6 1. Metal base machining: After drilling and removing burrs, the size of the gong must meet the requirements and there must be no burrs / flashing; S7. Pressing of metal substrate and high-frequency microwave board: When pressing, use pins to fix the metal base, vacuum for 5-10 minutes before pressing, and perform ultrasonic scanning after pressing. There must be no voids in the bonding sheet and the glue must not overflow; S8. Carbon oil control: The boards with qualified appearance are sent for carbon oil printing, and carbon oils of different square resistances are selected according to requirements; S9. Final inspection and shipment: Inspect the products according to IPC standards or customer standards.

[0008] Furthermore, in step S1, the drawings are optimized and designed according to the process capability, including pre-stretching of the film, compensation of the circuit, and drilling compensation. The circuit compensation is to increase the single side by 0.01-0.03mm on the original basis. The specific data is determined according to the copper thickness. The drilling compensation is to determine the size of the drilling hole according to the finished product aperture and plating thickness. At the same time, the plate is assembled to convert it into production materials within the company.

[0009] Furthermore, the step S2, cutting: setting the size of the working board according to the equipment process capability and the board utilization rate, and then cutting the board into the corresponding size, inner wet film: transferring the graphics to the working board according to the customer's information, quality points: line width / distance must be qualified, and there must be no poor exposure.

[0010] Further, the step S3, vacuum etching: use a vacuum etcher, use acidic etching solution to etch out all the graphics required by the customer, the quality of this process must be focused on, the line width / line spacing must be controlled within the qualified range; the interlayer deviation of the upper and lower layers must be controlled within 25um, the vacuum etcher can ensure the uniformity of the circuit of the entire working board after etching, automatic optical inspection: use an automatic scanning detection instrument to check the quality of the circuit after etching, confirm whether there is an open short circuit, whether there is a gap or a bump, pressing: use a vacuum hot press machine, use the corresponding pressing plate program to press different circuit layers together, quality points: the board thickness and tolerance must be qualified, thermal shock and reflow soldering without delamination / blistering problems, drilling: the purpose of this process is to drill through holes on the board surface, and the subsequent process can be chemically copper plated to achieve electrical conductivity of the upper and lower layers of copper. In this process, the drilling quality must be strictly controlled, the roughness in the hole is not allowed to be too large, and burrs, flashes, substrate damage / deformation and other problems are not allowed.

[0011] Furthermore, the step S4, chemical copper plating: is to use chemical reaction to plate a thin layer of copper in the drilled hole to achieve electrical conductivity of the upper and lower layers of the board, electroplating copper: thicken the copper in the hole and the copper on the surface to meet customer requirements to ensure the electrical performance requirements of the end customer, graphic transfer: according to the customer's information, transfer the graphic from the film to the working board, quality points: line width / distance must be qualified, vacuum etching: use a vacuum etcher, use acidic etching solution to bite out all the graphics required by the customer, the quality of this process must be focused on, the line width / line distance must be controlled within the qualified range; the interlayer deviation of the upper and lower layers must be controlled within 25um, solder mask: according to customer requirements, print a layer of insulating ink on the circuit board surface, but the pads of the plug-in and the patch must be fully exposed, characters: use a screen or character inkjet machine to print some customer identification letters, graphics and company logos for easy identification by end customers.

[0012] Furthermore, in step S5, since the metal base has blind holes and blind grooves, in the chemical gold plating process, the liquid medicine in the blind holes / grooves cannot be exchanged, resulting in the appearance of black holes. Therefore, in a dedicated production line, all liquid medicine tanks are installed with pneumatic vibration, and ultrasonic cleaning is installed in the washing tank before entering the gold tank to ensure that the liquid medicine in the blind holes is cleaned.

[0013] Furthermore, in step S6, the drilling should be carried out using a diamond-coated drill bit, and the drilling should be carried out in sections. The metal base thickness is 3mm, and the holes are drilled out in 3-5 sections. Special drilling parameters are used: lower cutter speed 1-2m / min, retracting cutter speed 8-10m / min, rotation speed 30KRPM, cutting amount 0.1-0.2mm / turn, drill cutter life 500-1000 holes / piece, and number of stacked plates 1PNL / stack. Using these parameters for production can effectively control the roughness in the hole and burrs and flash on the plate surface. The shape processing is carried out using a CNC machining center, using a coated double-edged gong cutter. The process parameters include: lower cutter speed 2-3m / min, retracting cutter speed 8-10m / min, rotation speed 25-30KRPM, gong cutter life 3-5m / piece, and number of stacked plates 1PNL / stack. The size of the gong must meet the requirements and there must be no burrs / flashing.

[0014] Furthermore, in step S7, during lamination, pins are used to fix the metal base, and then the bonding sheet is stacked, and then the high-frequency microwave PCB is placed according to the pin holes to align the PCB, the bonding sheet and the metal base, and there is no deviation during the lamination process. Special auxiliary materials are also used above and below. The auxiliary material is a release film that can withstand the highest temperature of 350°C. The use of this auxiliary material can ensure the lamination effect, and there will be no residual glue on the board surface. Before lamination, vacuum is drawn for 5-10 minutes, and then special lamination parameters are used: furnace temperature 120°C, lamination temperature 190-220°C, pressure 1.5-3.5MPa, of which 210°C, 3.5MPa conditions must be maintained for 90-120min, and the total lamination time is 240min. Ultrasonic scanning must be performed after lamination, and there must be no voids in the bonding sheet and the glue must not overflow.

[0015] Furthermore, in step S8, the boards with qualified appearance are sent to print carbon oil, and carbon oils of different square resistances are selected according to customer requirements. A 200-250 mesh pure steel screen is used for silk screen printing, and carbon oil is printed at the required position. Then, an IR furnace is used to bake the carbon oil, a laser film thickness tester is used to measure the thickness of the carbon oil, and a special test stand is used to measure the carbon resistance. The boards with high carbon resistance are directly scrapped, and the points with low carbon oil are cut using a laser cutting machine until the resistance value reaches the standard.

[0016] Furthermore, in step S9, the products are inspected according to IPC standards or customer standards, and qualified products can be packaged and shipped according to the packaging method required by the customer.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The dielectric layer of the multi-layer high-frequency metal substrate is generally a high-frequency material, which is firstly made into a multi-layer high-frequency microwave board, then pressed together with the metal base, and then surface treated and formed. The carbon oil board is generally used on the FR4 board, and is screen-printed with ordinary mesh, and the resistance value and thickness error are relatively large;

[0018] Furthermore, the produced post-pressed high-frequency metal-based carbon oil circuit board has good heat dissipation, excellent signal transmission performance, and the carbon oil thickness and resistance value meet customer requirements.

[0019] 2. The operation is simple. First, make the multi-layer high-frequency microwave circuit board, that is, complete the surface treatment, molding process and testing, check the appearance, and then press it together with the metal substrate. The board that has passed the test in all aspects can be screen-printed with carbon oil using a steel screen. The board with qualified resistance, thickness and appearance can be delivered to the customer. It can get the required products quickly and conveniently, saving the time required for work. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0021] Figure 2 It is a schematic diagram of the process structure of the present invention;

[0022] Figure 3 It is a schematic diagram of the key technology of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1: Figure 1-Figure 3 The technical solution shown is a method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board. In order to solve the problems of poor heat dissipation, poor signal transmission performance, and carbon oil thickness and resistance value failing to meet customer requirements of the post-pressed high-frequency metal-based carbon oil circuit board, the following are disclosed: S1, engineering design; S2, pretreatment preparation; S3, hole metallization control of the high-frequency microwave board; S4, copper plating processing;

[0025] S5, metal-based chemical gold plating processing; S6, metal-based machining; S7, lamination of metal substrate and high-frequency microwave board; S8, carbon oil control; S9, final inspection and shipment; specifically includes the following steps:

[0026] S1. Engineering design: When the metal substrate and the high-frequency microwave board are pressed together, the adhesive sheet used should be appropriately reduced by 0.2-0.5mm around the shape and the holes and slots to reserve space for the glue to flow out of the pressing; the circuit film of the high-frequency microwave board will become smaller when the film is compensated due to the corrosion of the liquid medicine, so the film should be appropriately enlarged; S2. Pretreatment preparation: Cutting: Set the size of the working board according to the equipment process capability and the utilization rate of the board, and then cut the board into the corresponding size; Inner wet film: According to the data, transfer the pattern to the working board, quality points: line Width / distance must be qualified, and there must be no poor exposure; S3, hole metallization control of high-frequency microwave board: the material of high-frequency microwave board is generally Teflon or ceramic mixed with FR4, and plasma cleaning must be performed before chemical copper plating; S4, copper plating processing: after copper plating, improve electrical performance requirements; S5, metal-based chemical gold plating processing: all liquid tanks are installed with pneumatic vibration, and ultrasonic cleaning is installed in the water washing tank before entering the gold tank to ensure that the liquid in the blind hole is cleaned, and a special gold sinking basket is used. The surface coating of the basket must have a certain elasticity, and there must be no basket marks around the metal base;

[0027] S6. Metal base machining: After drilling and removing burrs, the size of the hole must meet the requirements and there must be no burrs / flashes; S7. Lamination of metal substrate and high-frequency microwave board: When laminating, use pins to fix the metal base, vacuum for 5-10 minutes before laminating, and perform ultrasonic scanning after laminating. There must be no voids in the adhesive sheet and the glue must not overflow; S8. Carbon oil control: The boards with qualified appearance are sent for carbon oil printing, and carbon oils of different square resistances are selected according to requirements; S9. Final inspection and shipment: Inspect the products according to IPC standards or customer standards.

[0028] Step S1, according to the process capability, optimize the design of the drawing, pre-stretching of the film, compensation of the line, and compensation of drilling. The compensation of the line is to increase the single side by 0.01-0.03mm, the specific data should be determined according to the copper thickness, the drilling compensation is based on the finished product aperture and plating thickness to determine the size of the drilling, and at the same time, the plate is assembled to convert it into the company's internal production data, step S2, cutting: according to the equipment process capability, the board utilization rate to set the size of the work board, and then cut the board into the corresponding size, inner layer wet film: according to the customer's information, transfer the graphics to the work board, quality points: line width / spacing must be qualified, there can be no poor exposure, step S3, vacuum etching: use a vacuum etcher, use acidic etching solution to etch out all the graphics required by the customer, the quality of this process must be focused on, the line width / line spacing must be controlled within the qualified range; the interlayer deviation of the upper and lower layers must be controlled within 25um. The vacuum etching machine can ensure the uniformity of the circuit of the entire working board after etching. Automatic optical inspection: Use automatic scanning detection equipment to check the quality of the circuit after etching, confirm whether there is an open short circuit, whether there is a gap or a bump, Pressing: Use a vacuum hot press machine and use the corresponding pressing plate program to press different circuit layers together. Quality points: The board thickness and tolerance must be qualified, and there is no delamination / blistering problem with thermal shock and reflow soldering. Drilling: The purpose of this process is to drill through holes on the board surface, and then chemical copper plating can be performed in the later process to achieve electrical conductivity of the upper and lower layers of copper. In this process, the drilling quality must be strictly controlled, the roughness inside the hole is not allowed to be too large, and burrs, flashes, substrate damage / deformation and other problems are not allowed. Step S4, chemical copper plating: is to drill holes A thin layer of copper is plated in the hole by chemical reaction to achieve electrical conductivity between the upper and lower layers of the board. Electroplating copper: thicken the copper in the hole and the copper on the surface to meet customer requirements to ensure the electrical performance requirements of the end customer. Graphic transfer: transfer the graphics from the film to the working board according to the customer's information. Quality points: line width / distance must be qualified. Vacuum etching: use a vacuum etcher and acidic etching solution to etch out all the graphics required by the customer. The quality of this process must be focused on, and the line width / line distance must be controlled within the qualified range; the interlayer deviation of the upper and lower layers must be controlled within 25um. Solder mask: according to customer requirements, print a layer of insulating ink on the circuit board surface, but the pads of the plug-in and the patch must be fully exposed. Symbols: Use screen printing or character inkjet printer to print some customer's identification letters, graphics and company logos to facilitate the identification of end customers. Step S5: Because the metal base has blind holes and blind slots, the liquid in the blind holes / slots cannot be exchanged in the chemical gold plating process, resulting in black holes. Therefore, it is produced on a dedicated production line. All liquid tanks are installed with pneumatic vibration. Ultrasonic cleaning is installed in the water washing tank before entering the gold tank to ensure that the liquid in the blind holes is cleaned. Step S6: Use diamond-coated drill bits for drilling. Drill in sections. The metal base is 3mm thick and drilled in 3-5 sections. Use special drilling parameters: down-cutting speed 1-2m / min, back-cutting speed 8-10m / min, rotation speed 30KRPM, cutting amount 0.1-0.2mm / circle, drill life 500-1000 holes / piece, number of stacks 1PNL / stack. Using these parameters for production can effectively control the roughness in the hole and the burrs and flashes on the board surface. The appearance processing is carried out using a CNC machining center, using a coated double-edged gong cutter. The process parameters include: down cutter speed 2-3m / min, back cutter speed 8-10m / min, rotation speed 25-30KRPM, gong cutter life 3-5m / piece, number of stacks 1PNL / stack. The gong size must meet the requirements and there must be no burrs / flashing. Step S7, when pressing, use pins to fix the metal base, then stack the bonding sheet, and then place the high-frequency microwave PCB according to the pin hole to align the PCB, bonding sheet and metal base, and do not deviate during the pressing process. Special auxiliary materials are also used on the upper and lower parts. The auxiliary material is a release film that can withstand the highest temperature: 350℃. Using this auxiliary material can ensure the pressing effect and there will be no residual glue on the board surface. Vacuum for 5-10 minutes before pressing, and then use special The pressing parameters are as follows: the temperature of the furnace is 120℃, the pressing temperature is 190-220℃, the pressure is 1.5-3.5MPa, and the conditions of 210℃ and 3.5MPa should be maintained for 90-120min, and the total pressing time is 240min. Ultrasonic scanning should be performed after pressing. There should be no voids in the bonding sheet and the glue should not overflow. Step S8: The boards with qualified appearance are sent to print carbon oil. Carbon oil with different square resistances is selected according to the customer's requirements. A 200-250 mesh pure steel screen is used for screen printing. Carbon oil is printed at the required position, and then an IR furnace is used to bake the carbon oil. The thickness of the carbon oil is measured by a laser film thickness tester. A special test stand is used to measure the carbon resistance. The carbon resistance is directly scrapped if it is too high. The points with low carbon oil are cut by a laser cutting machine until the resistance value reaches the standard. Step S9: The products are inspected according to the IPC standard or the customer's standard. The qualified ones can be packaged and shipped. They are packaged and shipped according to the packaging method required by the customer. .

[0029] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board, comprising S1, engineering design; S2, pretreatment preparation; S3, hole metallization control of the high-frequency microwave board; S4, copper plating processing; S5, metal-based chemical gold plating processing; S6, metal-based machining; S7, pressing of the metal substrate and the high-frequency microwave board; S8, carbon oil control; S9, final inspection and shipment; It is characterized in that The specific steps include: S1. Engineering Design: When the metal substrate is pressed together with the high-frequency microwave board, the adhesive sheet used should be appropriately reduced by 0.2-0.5mm around its shape and around the holes and slots to reserve space for the glue to flow out; The circuit film of the high-frequency microwave board will become smaller when the film is compensated due to corrosion by the liquid medicine, so the film should be appropriately increased; S2. Pretreatment preparation: Cutting: Set the size of the work plate according to the equipment process capability and plate utilization, and then cut the plate into the corresponding size; Inner wet film: According to the data, transfer the graphics to the working board. Quality points: line width / distance must be qualified, and there must be no poor exposure; S3. Hole metallization control of high-frequency microwave boards: The material of high-frequency microwave boards is generally Teflon or ceramic mixed with FR4, and plasma cleaning is required before chemical copper plating; S4, copper plating processing: After copper plating, the electrical performance requirements are improved; S5. Metal-based chemical gold plating processing: All the medicine tanks are installed with pneumatic vibration, and ultrasonic cleaning is installed in the water washing tank before entering the gold tank to ensure that the medicine in the blind hole is cleaned. A special gold sinking basket is used, and the surface coating of the basket must have a certain elasticity, and there should be no basket marks around the metal base; S6. Metal-based machining: After drilling and removing burrs, the hole size must meet the requirements and there must be no burrs or flashes. S7. Lamination of metal substrate and high-frequency microwave board: When pressing, use pins to fix the metal base. Vacuum for 5-10 minutes before pressing. Perform ultrasonic scanning after pressing. There should be no voids in the adhesive sheet and the glue should not overflow. S8, Carbon oil control: The boards with qualified appearance are sent to be printed with carbon oil, and carbon oils with different square resistances are selected according to requirements; S9, Final Inspection and Shipment: Inspect products according to IPC standards or customer standards.

2. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: In step S1, according to the process capability, the drawings are optimized and designed, and the film is pre-stretched, the circuit is compensated, and the drilling compensation is performed. The circuit compensation is to increase the single side by 0.01-0.03mm on the original basis. The specific data is determined according to the copper thickness. The drilling compensation is to determine the size of the drilling hole according to the finished product aperture and the plating thickness. At the same time, the plate is assembled to convert it into the company's internal production data.

3. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: The step S2, cutting: setting the size of the working board according to the equipment process capability and the board utilization rate, and then cutting the board into the corresponding size, inner wet film: transferring the pattern to the working board according to the customer's information, quality points: the line width / distance must be qualified, and there must be no poor exposure.

4. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: The step S3, vacuum etching: use a vacuum etcher, use acidic etching solution to etch out all the graphics required by the customer, the quality of this process must be focused on, the line width / line spacing must be controlled within the qualified range; the interlayer deviation of the upper and lower layers must be controlled within 25um, the vacuum etcher can ensure the uniformity of the circuit of the entire working board after etching, automatic optical inspection: use an automatic scanning detection instrument to check the quality of the circuit after etching, confirm whether there is an open short circuit, whether there is a gap or a bump, pressing: use a vacuum hot press machine, use the corresponding pressing plate program to press different circuit layers together, quality points: the board thickness and tolerance must be qualified, and there is no delamination / blistering problem with thermal shock and reflow soldering, drilling: the purpose of this process is to drill through holes on the board surface, and the subsequent process can be chemically copper plated to achieve electrical conductivity of the upper and lower layers of copper. In this process, the drilling quality must be strictly controlled, the roughness in the hole is not allowed to be too large, and burrs, flashes, substrate damage / deformation and other problems are not allowed.

5. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: The step S4, chemical copper plating: is to use chemical reaction to plate a thin layer of copper in the drilled hole to achieve electrical conductivity of the upper and lower layers of the board, electroplating copper: thicken the copper in the hole and the copper on the surface to meet customer requirements to ensure the electrical performance requirements of the end customer, graphic transfer: according to the customer's information, transfer the graphic from the film to the working board, quality points: line width / distance must be qualified, vacuum etching: use a vacuum etcher, use acidic etching solution to bite out all the graphics required by the customer, the quality of this process must be focused on, the line width / line distance must be controlled within the qualified range; the interlayer deviation of the upper and lower layers must be controlled within 25um, solder mask: according to customer requirements, print a layer of insulating ink on the circuit board surface, but the pads of the plug-in and the patch must be fully exposed, characters: use a screen or character inkjet machine to print some customer identification letters, graphics and company logos for easy identification by end customers.

6. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: In step S5, since the metal base has blind holes and blind grooves, in the chemical gold plating process, the liquid medicine in the blind holes / grooves cannot be exchanged, resulting in the appearance of black holes. Therefore, in a dedicated production line, all liquid medicine tanks are installed with pneumatic vibration, and ultrasonic cleaning is installed in the washing tank before entering the gold tank to ensure that the liquid medicine in the blind holes is cleaned.

7. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: In the step S6, a diamond-coated drill bit is used for drilling, and the drilling is carried out in sections. The metal base thickness is 3mm, and the holes are drilled out in 3-5 sections. Special drilling parameters are used: lowering speed 1-2m / min, retracting speed 8-10m / min, rotation speed 30KRPM, cutting amount 0.1-0.2mm / turn, drill life 500-1000 holes / piece, and number of stacked plates 1PNL / stack. Using these parameters for production can effectively control the roughness in the hole and burrs and flash on the plate surface. The shape processing is carried out using a CNC machining center, using a coated double-edged gong cutter. The process parameters include: lowering speed 2-3m / min, retracting speed 8-10m / min, rotation speed 25-30KRPM, gong cutter life 3-5m / piece, and number of stacked plates 1PNL / stack. The size of the gong must meet the requirements and there must be no burrs / flashing.

8. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: In step S7, during lamination, a pin is used to fix the metal base, and then the bonding sheet is stacked, and then a high-frequency microwave PCB is placed according to the pin hole to align the PCB, the bonding sheet and the metal base, and there is no deviation during the lamination process. Special auxiliary materials are also used on the upper and lower parts. The auxiliary material is a release film that can withstand a maximum temperature of 350°C. The use of this auxiliary material can ensure the lamination effect and there will be no residual glue on the board surface. Before lamination, vacuum is drawn for 5-10 minutes, and then special lamination parameters are used: furnace temperature of 120°C, lamination temperature of 190-220°C, pressure of 1.5-3.5MPa, wherein the conditions of 210°C and 3.5MPa must be maintained for 90-120min, and the total lamination time is 240min. Ultrasonic scanning must be performed after lamination, and there must be no voids in the bonding sheet and the glue must not overflow.

9. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: In step S8, the boards with qualified appearance are sent to be printed with carbon oil. Carbon oils with different square resistances are selected according to customer requirements. A 200-250 mesh pure steel screen is used for screen printing. Carbon oil is printed at the required position, and then an IR furnace is used to bake the carbon oil. A laser film thickness tester is used to measure the thickness of the carbon oil. A special test stand is used to measure the carbon resistance. The boards with high carbon resistance are directly scrapped. The points with low carbon oil are cut with a laser cutting machine until the resistance value reaches the standard.

10. The method for producing a post-pressed multi-layer high-frequency metal-based carbon oil circuit board according to claim 1, characterized in that: In step S9, the products are inspected according to IPC standards or customer standards, and qualified products can be packaged and shipped, and the products are packaged and shipped according to the packaging method required by the customer.

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