PCB preparation process and PCB board

Abstract

The present invention relates to the technical field of circuit board preparation, specifically to a PCB preparation process and a PCB board. The PCB preparation process and PCB board prepare a substrate core board according to the required size of the PCB circuit board. The substrate core board is formed by mixing composite materials, and a metal layer is provided on one or both sides of the substrate core board. The metal layer is exposed, developed, and etched to form a circuit. The substrate core board prepared by the process can provide better material properties for the PCB board. The thermal conductivity and heat dissipation performance of the circuit board are improved by fillers and aluminum foil. The modified resin and antioxidant combined with the filler can further improve the aging or degradation resistance of the circuit board, thereby improving the PCB board's ability to meet the packaging requirements of high-power devices. The connection stability between the metal layer and the substrate core board can be guaranteed by controlling the hot pressing molding temperature and pressure.

Description

Technical Field

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

[0002] Over the past decade, my country's printed circuit board manufacturing industry has grown rapidly, ranking first in the world in both total output value and total volume. Printed circuit boards, also known as printed circuit boards (PCBs), provide electrical connections for electronic components. They can be categorized by the number of layers, including single-sided, double-sided, four-layer, six-layer, and other multi-layer boards. Their design primarily involves layout design. The primary advantage of using PCBs is that they significantly reduce wiring and assembly errors, improving automation and increasing production efficiency. The term "printed circuit board" generally refers to a bare board—that is, a circuit board without fixed electronic components.

[0003] Printed circuit boards (PCBs) are the most common packaging substrates on the market today. They consist of an organic insulating layer and a metal wiring layer. The insulating layer typically uses an organic resin material as an adhesive, while the wiring layer is made from copper foil through a high-temperature lamination process. PCBs are inexpensive and easy to machine, but due to the poor heat dissipation performance of organic materials, they are susceptible to thermal degradation and thermal aging, and even carbonization, at high temperatures. Therefore, PCBs struggle to meet the packaging needs of high-power devices. This is especially true for conventional multilayer PCBs, which can lead to further increases in board thickness and even worse heat dissipation performance. Furthermore, current manufacturing processes can easily lead to poor bonding between the metal wiring layer and the organic insulating layer of the substrate, resulting in unstable PCB quality. Therefore, a PCB manufacturing process is needed to improve the heat dissipation performance and product quality stability of PCBs. In light of this, we propose a PCB manufacturing process and PCB board. Summary of the Invention

[0004] In order to make up for the above deficiencies, the present invention provides a PCB preparation process and a PCB board.

[0005] The technical solution of the present invention is:

[0006] A PCB preparation process includes the following processes:

[0007] A substrate core board is prepared according to the required size of the PCB circuit board. The substrate core board is formed by mixing composite materials, and a metal layer is provided on one or both sides of the substrate core board. The metal layer is exposed, developed and etched to form a circuit.

[0008] Preferably, the specific proportions of the components of the composite material are: 35-50 parts of filler, 20-40 parts of ABS modified resin, 25-35 parts of organic binder, 2-5 parts of silane coupling agent, 0.4-1 part of curing agent, and 0.05-1 part of antioxidant.

[0009] Preferably, the filler comprises 45-60% magnesium oxide or aluminum oxide, 5-20% aluminum nitride, 10-30% silicon nitride or silicon dioxide, and 5-15% thermally conductive silicone grease or silica gel by weight. It should be noted that the filler primarily serves as a flame retardant and thermally conductive material. Both are highly thermally conductive materials, capable of conducting and absorbing heat generated by the circuit board. They also possess excellent insulation properties and a low coefficient of thermal expansion, preventing significant thermal expansion changes in the core substrate that could damage the material.

[0010] Preferably, the ABS modified resin uses acrylonitrile-butadiene-styrene copolymer as a base material, and is added with any one or more of polycarbonate, polyamide, and polyester resin accounting for 10-35% of the mass of the base material.

[0011] Specifically, polycarbonate is a tough thermoplastic resin with excellent flame retardancy, wear resistance and oxidation resistance. When mixed with acrylonitrile-butadiene-styrene copolymer, it can improve the flame retardancy of ABS, giving it good mechanical strength, toughness and flame retardancy; polyamide can improve the impact resistance, heat resistance and chemical resistance of ABS; polyester resin can improve the heat resistance, strength, chemical resistance and fluidity of ABS; these three materials mixed with the matrix material can have better modification functions than a single resin, and are suitable for use in high-power circuit boards.

[0012] Preferably, the substrate core board preparation process is specifically as follows: weigh the components of the composite material according to their mass fractions and mix them evenly, put them into a high-temperature furnace for heating, and control the heating temperature gradient as follows: heat the room temperature to 65-90°C at 3-5°C / min, reduce the heating rate to 1-2.5°C / min and continue to heat to 170-210°C, keep the temperature for 2-4 hours, and then use the casting method to make the molten material into a substrate core board of the required thickness, and cut the substrate core board according to the size of the PCB model for later use.

[0013] Preferably, the contact surface between the spare base core board and the metal layer is polished, and then thermal conductive adhesive is applied to the contact surface. Aluminum foil and copper foil are then stacked on the thermal conductive adhesive in sequence. The board is then placed in a hot press for hot pressing and sintering. After the heating temperature is controlled to stabilize, pressure is applied. After the hot pressing is completed, the board is cooled naturally or evenly to produce a copper clad laminate for use. The thermal conductive adhesive and aluminum foil both act as heat conductors, quickly conducting away the heat generated by the circuit, achieving rapid heat dissipation performance.

[0014] Preferably, the heating temperature is 160-200°C and the controlled pressure is 3-8MPa. The purpose of the heating temperature and pressure is to promote the forming and curing between the copper foil and the aluminum foil and the substrate core board, prevent separation, and form a composite structure. The temperature needs to be lower than the melting temperature of the substrate core board to prevent the copper foil from being embedded in the substrate core board due to excessive temperature. While controlling the pressure, it can avoid the pressure being too low and the resulting looseness after curing.

[0015] Preferably, the thickness of the aluminum foil is 8-25 μm, and the thickness of the copper foil is 10-300 μm.

[0016] Preferably, the specific process steps of exposure, development and etching are: grinding the copper clad surface of the standby copper clad board and then laminating or coating it with a dry film. The main function of the grinding plate is to solve the problems of surface cleanliness and surface roughness, and it can remove oxidation, increase the roughness of the copper surface, and facilitate the adhesion of the dry film to the copper surface; using an exposure machine to expose the dry film with ultraviolet light, using sodium carbonate to rinse and remove the unexposed dry film, and then using acidic copper chloride or copper sulfate solution to dissolve and etch away excess copper to obtain the required circuit pattern.

[0017] Specifically, the dry film is a high molecular compound that can produce a polymerization reaction after being irradiated by ultraviolet rays, a reaction process in which monomers synthesize polymers, thereby forming a stable material attachment, thereby achieving the goal of blocking etching.

[0018] A PCB board is manufactured by the above-mentioned PCB manufacturing process.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The PCB preparation process and PCB board are characterized by a substrate core board prepared by the process that can provide the PCB board with better material properties, and by improving the thermal conductivity and heat dissipation performance of the circuit board through fillers and aluminum foil. In addition, the modified resin and antioxidant combined with the filler can further improve the aging or degradation resistance of the circuit board, thereby improving the PCB board's ability to meet the packaging requirements of high-power devices. By controlling the hot pressing molding temperature and pressure, a stable connection between the metal layer and the substrate core board can be ensured through the thermal conductive adhesive. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0022] The present invention describes the above technical solution in detail through the following embodiments:

[0023] Example 1

[0024] A PCB board, the specific PCB preparation process includes the following:

[0025] The substrate core board of the required size is prepared or cut according to the size specifications of the PCB circuit board. The substrate core board is formed by mixing composite materials, and a metal layer is provided on one or both sides of the substrate core board. The metal layer is exposed, developed and etched to form a circuit.

[0026] First, the following raw materials are prepared: 50 parts of filler, 20 parts of ABS modified resin, 25 parts of organic adhesive, 1 part of curing agent, 3 parts of silane coupling agent, and 1 part of antioxidant; the weight percentage of each component in the filler is 60% aluminum oxide, 15% aluminum nitride, 20% silicon nitride, and 5% thermal grease, and the ABS modified resin includes polycarbonate accounting for 10% by weight of acrylonitrile-butadiene-styrene copolymer.

[0027] Weigh the filler components by mass, mix them, and place them in a planetary ball mill for 2 hours to crush and refine them. Control the speed at 2000r / min. Mix the milled filler and other raw materials, and heat them in a high-temperature furnace. Control the heating temperature gradient as follows: heat at 5°C / min to 90°C at room temperature, reduce the heating rate to 2°C / min, and continue to heat to 180°C. After keeping warm for 4 hours, use the fully melted material to form a substrate core board of the required thickness through the casting method. Cut the substrate core board according to the size of the PCB model for later use. It should be noted that the casting method refers to the molten material being extruded through an extruder, allowing the molten material to pass through a cooling roller, and then undergo processes such as stretching, trimming, coiling, and pressing to form a sheet or plate of a certain thickness.

[0028] Subsequently, the contact surface between the spare substrate core board and the metal layer is roughened, and then thermal conductive adhesive is coated on the rough contact surface. Subsequently, 25μm thick aluminum foil and 80μm thick copper foil are stacked on the thermal conductive adhesive in sequence, and then placed in a hot press for hot pressing and sintering. The heating temperature is controlled at 170℃ and the pressure is applied at 6MPa. After the hot pressing is completed, it is naturally cooled to obtain a copper clad laminate for use.

[0029] The spare copper clad board is exposed, developed and etched according to the specific circuit diagram. First, the copper surface of the spare copper clad board is polished smooth and then a dry film of corresponding size is attached. The dry film is exposed to ultraviolet light by an exposure machine. The light-transmitting part of the dry film will be cured, forming a protective film on the copper surface to prevent etching. The other dry films outside the corresponding circuit diagram will not be exposed to ultraviolet light and are still uncured. The dry films that have not been exposed and cured are washed away with analytical pure sodium carbonate solution. Then, the excess copper is dissolved and etched away with an acidic cupric chloride solution to obtain the required circuit pattern. Finally, the protective film left on the circuit pattern is removed with analytical pure sodium hydroxide solution after film stripping. At this time, the circuit pattern is exposed on the substrate core board.

[0030] Example 2

[0031] A PCB board, the specific PCB preparation process includes the following:

[0032] The substrate core board of the required size is prepared or cut according to the size specifications of the PCB circuit board. The substrate core board is formed by mixing composite materials, and a metal layer is provided on one or both sides of the substrate core board. The metal layer is exposed, developed and etched to form a circuit.

[0033] First, the following raw materials are prepared: 40 parts of filler, 20 parts of ABS modified resin, 35 parts of organic adhesive, 1 part of curing agent, 3 parts of silane coupling agent, and 1 part of antioxidant; the weight percentage of each component in the filler is 60% aluminum oxide, 15% aluminum nitride, 20% silicon nitride, and 5% thermal grease, and the ABS modified resin includes polycarbonate accounting for 10% by weight of acrylonitrile-butadiene-styrene copolymer.

[0034] Weigh the filler components by mass, mix them, and place them in a planetary ball mill for 2 hours to crush and refine them. Control the speed at 2000r / min. Mix the milled filler and other raw materials, and heat them in a high-temperature furnace. Control the heating temperature gradient as follows: heat at 5°C / min to 90°C at room temperature, reduce the heating rate to 2°C / min, and continue to heat to 180°C. After keeping warm for 4 hours, use the fully melted material to form a substrate core board of the required thickness through the casting method. Cut the substrate core board according to the size of the PCB model for later use. It should be noted that the casting method refers to the molten material being extruded through an extruder, allowing the molten material to pass through a cooling roller, and then undergo processes such as stretching, trimming, coiling, and pressing to form a sheet or plate of a certain thickness.

[0035] Subsequently, the contact surface between the spare substrate core board and the metal layer is roughened, and then thermal conductive adhesive is coated on the rough contact surface. Subsequently, 25μm thick aluminum foil and 80μm thick copper foil are stacked on the thermal conductive adhesive in sequence, and then placed in a hot press for hot pressing and sintering. The heating temperature is controlled at 170℃ and the pressure is applied at 6MPa. After the hot pressing is completed, it is naturally cooled to obtain a copper clad laminate for use.

[0036] The spare copper clad board is exposed, developed and etched according to the specific circuit diagram. First, the copper surface of the spare copper clad board is polished smooth and then a dry film of corresponding size is attached. The dry film is exposed to ultraviolet light by an exposure machine. The light-transmitting part of the dry film will be cured, forming a protective film on the copper surface to prevent etching. The other dry films outside the corresponding circuit diagram will not be exposed to ultraviolet light and are still uncured. The dry films that have not been exposed and cured are washed away with analytical pure sodium carbonate solution. Then, the excess copper is dissolved and etched away with an acidic cupric chloride solution to obtain the required circuit pattern. Finally, the protective film left on the circuit pattern is removed with analytical pure sodium hydroxide solution after film stripping. At this time, the circuit pattern is exposed on the substrate core board.

[0037] Example 3

[0038] A PCB board, the specific PCB preparation process includes the following:

[0039] The substrate core board of the required size is prepared or cut according to the size specifications of the PCB circuit board. The substrate core board is formed by mixing composite materials, and a metal layer is provided on one or both sides of the substrate core board. The metal layer is exposed, developed and etched to form a circuit.

[0040] First, the following raw materials are prepared: 50 parts of filler, 25 parts of ABS modified resin, 20 parts of organic adhesive, 1 part of curing agent, 3 parts of silane coupling agent, and 1 part of antioxidant; the weight percentage of each component in the filler is 60% aluminum oxide, 15% aluminum nitride, 20% silicon nitride, and 5% thermal grease, and the ABS modified resin includes polycarbonate accounting for 10% by weight of acrylonitrile-butadiene-styrene copolymer.

[0041] Weigh the filler components by mass, mix them, and place them in a planetary ball mill for 2 hours to crush and refine them. Control the speed at 2000r / min. Mix the milled filler and other raw materials, and heat them in a high-temperature furnace. Control the heating temperature gradient as follows: heat at 5°C / min to 90°C at room temperature, reduce the heating rate to 2°C / min, and continue to heat to 180°C. After keeping warm for 4 hours, use the fully melted material to form a substrate core board of the required thickness through the casting method. Cut the substrate core board according to the size of the PCB model for later use. It should be noted that the casting method refers to the molten material being extruded through an extruder, allowing the molten material to pass through a cooling roller, and then undergo processes such as stretching, trimming, coiling, and pressing to form a sheet or plate of a certain thickness.

[0042] Subsequently, the contact surface between the spare substrate core board and the metal layer is roughened, and then thermal conductive adhesive is coated on the rough contact surface. Subsequently, 25μm thick aluminum foil and 80μm thick copper foil are stacked on the thermal conductive adhesive in sequence, and then placed in a hot press for hot pressing and sintering. The heating temperature is controlled at 170℃ and the pressure is applied at 6MPa. After the hot pressing is completed, it is naturally cooled to obtain a copper clad laminate for use.

[0043] The spare copper clad board is exposed, developed and etched according to the specific circuit diagram. First, the copper surface of the spare copper clad board is polished smooth and then a dry film of corresponding size is attached. The dry film is exposed to ultraviolet light by an exposure machine. The light-transmitting part of the dry film will be cured, forming a protective film on the copper surface to prevent etching. The other dry films outside the corresponding circuit diagram will not be exposed to ultraviolet light and are still uncured. The dry films that have not been exposed and cured are washed away with analytical pure sodium carbonate solution. Then, the excess copper is dissolved and etched away with an acidic cupric chloride solution to obtain the required circuit pattern. Finally, the protective film left on the circuit pattern is removed with analytical pure sodium hydroxide solution after film stripping. At this time, the circuit pattern is exposed on the substrate core board.

[0044] Example 4

[0045] A PCB board, the specific PCB preparation process includes the following:

[0046] The substrate core board of the required size is prepared or cut according to the size specifications of the PCB circuit board. The substrate core board is formed by mixing composite materials, and a metal layer is provided on one or both sides of the substrate core board. The metal layer is exposed, developed and etched to form a circuit.

[0047] First, the following raw materials are prepared: 50 parts of filler, 20 parts of ABS modified resin, 25 parts of organic adhesive, 1 part of curing agent, 3.95 parts of silane coupling agent, and 0.05 part of antioxidant; the weight percentages of the components in the filler are 60% aluminum oxide, 15% aluminum nitride, 20% silicon nitride, and 5% thermal grease, and the ABS modified resin includes polycarbonate accounting for 10% by weight of acrylonitrile-butadiene-styrene copolymer.

[0048] Weigh the filler components by mass, mix them, and place them in a planetary ball mill for 2 hours to crush and refine them. Control the speed at 2000r / min. Mix the milled filler and other raw materials, and heat them in a high-temperature furnace. Control the heating temperature gradient as follows: heat at 5°C / min to 90°C at room temperature, reduce the heating rate to 2°C / min, and continue to heat to 180°C. After keeping warm for 4 hours, use the fully melted material to form a substrate core board of the required thickness through the casting method. Cut the substrate core board according to the size of the PCB model for later use. It should be noted that the casting method refers to the molten material being extruded through an extruder, allowing the molten material to pass through a cooling roller, and then undergo processes such as stretching, trimming, coiling, and pressing to form a sheet or plate of a certain thickness.

[0049] Subsequently, the contact surface between the spare substrate core board and the metal layer is roughened, and then thermal conductive adhesive is coated on the rough contact surface. Subsequently, 25μm thick aluminum foil and 80μm thick copper foil are stacked on the thermal conductive adhesive in sequence, and then placed in a hot press for hot pressing and sintering. The heating temperature is controlled at 170℃ and the pressure is applied at 6MPa. After the hot pressing is completed, it is naturally cooled to obtain a copper clad laminate for use.

[0050] The spare copper clad board is exposed, developed and etched according to the specific circuit diagram. First, the copper surface of the spare copper clad board is polished smooth and then a dry film of corresponding size is attached. The dry film is exposed to ultraviolet light by an exposure machine. The light-transmitting part of the dry film will be cured, forming a protective film on the copper surface to prevent etching. The other dry films outside the corresponding circuit diagram will not be exposed to ultraviolet light and are still uncured. The dry films that have not been exposed and cured are washed away with analytical pure sodium carbonate solution. Then, the excess copper is dissolved and etched away with an acidic cupric chloride solution to obtain the required circuit pattern. Finally, the protective film left on the circuit pattern is removed with analytical pure sodium hydroxide solution after film stripping. At this time, the circuit pattern is exposed on the substrate core board.

[0051] Comparative Example 1

[0052] The difference between this comparative example and Example 1 is that: in this comparative example, no filler is added, and ABS modified resin is used to replace the filler in terms of mass fraction, and other conditions are the same.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 1 is that: in this comparative example, ABS resin is not added, and filler is used to replace the mass fraction of ABS resin, and other conditions are the same.

[0055] Comparative Example 3

[0056] The difference between this comparative example and Example 1 is that no antioxidant is added in this comparative example, and other conditions are the same.

[0057] An aging test was performed on the samples of Examples 1-4 and Comparative Examples 1-3 with reference to GB / T14522-2008, GB / T16585-2008, and GB / T16422.3-2008 to observe the surface oxidation of the samples under the light test; and a heat conduction test of the samples was performed with reference to GB / T29313-2012 to test the time T (seconds) for the temperature to drop by 10°C under the same conditions.

[0058] Antioxidant properties T (seconds) Example 1 No surface changes 11 Example 2 No surface changes 13 Example 3 No surface changes 11 Example 4 There are fine wrinkles and cracks on the surface 10 Comparative Example 1 No surface changes 23 Comparative Example 2 No surface changes 8 Comparative Example 3 Surface yellowing and cracking 11

[0059] As shown in the table above, antioxidants can play an antioxidant role, and fillers have excellent thermal conductivity, which can improve the thermal conductivity of circuit boards. High thermal conductivity is conducive to improving the ability to dissipate heat and cool down to the air.

[0060] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A PCB preparation process, characterized by: The process includes: A substrate core board is prepared according to the required size of the PCB circuit board. The substrate core board is formed by mixing composite materials, and a metal layer is provided on one or both sides of the substrate core board. The metal layer is exposed, developed and etched to form a circuit; The specific proportions of the components of the composite material are: 35-50 parts of filler, 20-40 parts of ABS modified resin, 25-35 parts of organic binder, 2-5 parts of silane coupling agent, 0.4-1 parts of curing agent, and 0.05-1 parts of antioxidant; The mass percentage of each component in the filler is 45-60% magnesium oxide or aluminum oxide, 5-20% aluminum nitride, 10-30% silicon nitride or silicon dioxide, and 5-15% thermal conductive silicone grease or thermal conductive silicone; The ABS modified resin is based on acrylonitrile-butadiene-styrene copolymer, and is added with any one or more of polycarbonate, polyamide, and polyester resin accounting for 10-35% of the mass of the base material; The specific process for preparing the substrate core board is as follows: weigh the various components of the composite material by mass and mix them evenly. Heat them in a high-temperature furnace. Control the heating temperature gradient as follows: heat the room temperature to 65-90°C at a rate of 3-5°C / min, reduce the heating rate to 1-2.5°C / min, and continue to heat to 170-210°C. After keeping the temperature for 2-4 hours, cast the molten material into the substrate core board of the required thickness. Cut the substrate core board according to the size of the PCB model for later use. The contact surface between the spare substrate core board and the metal layer is polished, and then thermal conductive glue is applied on the contact surface. Aluminum foil and copper foil are then stacked on the thermal conductive glue in sequence, and then placed in a hot press for hot pressing and sintering. After the heating temperature is controlled to be stable, pressure is applied. After the hot pressing is completed, it is naturally cooled or evenly cooled to obtain a copper clad laminate for use.

2. The PCB preparation process according to claim 1, wherein: The heating temperature is 160-200°C and the control pressure is 3-8MPa.

3. The PCB preparation process according to claim 2, wherein: The thickness of aluminum foil is 8-25μm, and the thickness of copper foil is 10-300μm.

4. The PCB preparation process according to claim 3, wherein: The specific process steps of exposure, development and etching are as follows: the copper-clad surface of the standby copper-clad board is polished and then laminated or coated with a dry film, the dry film is exposed to ultraviolet light by an exposure machine, the unexposed dry film is removed by washing with sodium carbonate, and then the excess copper is dissolved and etched away using an acidic copper chloride or copper sulfate solution to obtain the desired circuit pattern.

5. A PCB board manufactured by the PCB manufacturing process according to any one of claims 1 to 4.