Eco-friendly printed circuit board for high and low temperature applications

Abstract

A multilayer printed circuit board (PCB) is fabricated using basalt fibers instead of glass fibers. The use of basalt fibers instead of glass fibers makes the PCB more environmentally friendly without sacrificing mechanical and electrical characteristics. The present invention relates to a multilayer PCB comprising a basalt fiber core comprising a basalt fiber prepreg provided between two copper layers. A first copper layer and a second copper layer are coupled to different sides of the basalt fiber core. A first basalt fiber prepreg is coupled to the first copper layer and a second basalt fiber prepreg is coupled to the second copper layer.

Description

Background Art

[0001] Printed circuit boards (PCBs) come in a variety of different types and are widely used in a variety of different electronic devices. One common type of PCB is called FR-4 PCB. FR-4 PCB is manufactured using fiberglass fabric and epoxy resin. These fiberglass fabric-based PCBs have excellent electrical and mechanical properties, which contribute to the overall reliability and performance of the electronic device.

[0002] However, due in part to the manufacturing process and the materials used in production, glass fiber-based PCBs have a significant environmental impact. For example, the production of glass fiber involves an energy-intensive process that produces carbon dioxide emissions. In addition, the raw materials used during manufacturing, such as silica sand and chemicals, are non-renewable resources. The complex composition of glass fiber and epoxy resin also makes recycling and disposal challenging, which can lead to the accumulation of electronic waste.

[0003] Therefore, it would be beneficial to reduce the environmental impact of PCB manufacturing by replacing glass fiber fabrics with environmentally friendly materials while maintaining or improving the electrical and mechanical properties of the PCB. Summary of the invention

[0004] The present application describes a printed circuit board (PCB) manufactured using a naturally occurring material instead of glass fiber or glass fiber fabric. In an example, the naturally occurring material is basalt fiber derived from volcanic rock. Basalt fiber is used to produce basalt fiber fabric. Because basalt fiber is derived from naturally occurring volcanic rock, basalt fiber (and basalt fiber fabric) is more sustainable and environmentally friendly than glass fiber.

[0005] Additionally, the production of basalt fibers requires less energy and emits fewer greenhouse gases than the production of glass fibers. Basalt fibers are easier to recycle and reuse than glass fibers, which reduces waste. Basalt fibers also have better mechanical properties and higher electrical insulation than those of glass fibers.

[0006] In addition, basalt fiber is inert, has high temperature resistance and high corrosion resistance. Basalt fiber also has excellent thermal characteristics, with a melting temperature between 1500°C and 1700°C. As a result, basalt fiber can easily withstand temperatures between 1100°C and 1200°C without any physical damage. Basalt fiber can also be used as a heat-resistant insulation material during the PCB manufacturing process.

[0007] Thus, examples of the present disclosure describe a PCB including a basalt fiber core. In an example, the basalt fiber core includes a first prepreg, the first prepreg including a basalt fiber fabric and an epoxy resin. The basalt fiber core also includes a first copper layer coupled to a first surface of the first prepreg and a second copper layer coupled to a second surface of the first prepreg. The PCB also includes a third copper layer coupled to the first copper layer and a fourth copper layer coupled to the second copper layer. A second prepreg is coupled to the third copper layer, and a third prepreg is coupled to the fourth copper layer. In an example, the second prepreg and the third prepreg also include a basalt fiber fabric and an epoxy resin.

[0008] The example also describes a method for making a basalt fiber prepreg for a PCB. In the example, the basalt fiber prepreg is made by drying a basalt fiber fabric and impregnating the basalt fiber fabric with an epoxy resin. The basalt fiber fabric and the epoxy resin are compressed and cured. The basalt fiber fabric and the epoxy resin are then cooled and compressed simultaneously.

[0009] A method of manufacturing a basalt fiber core for a PCB is also described. The method comprises drying a basalt fiber prepreg, and then impregnating the basalt fiber prepreg with an epoxy resin. A first copper layer is attached to a first side of the basalt fiber prepreg, and a second copper layer is attached to a second side of the basalt fiber prepreg. The basalt fiber prepreg, the first copper layer, and the second copper layer are then subjected to a compression curing process. After the compression curing process is completed, the basalt fiber prepreg, the first copper layer, and the second copper layer are simultaneously cooled and compressed.

[0010] In yet another example, a method for manufacturing a PCB is disclosed. In an example, the method includes dipping a first prepreg in an epoxy resin. In an example, the first prepreg includes a basalt fiber fabric and an epoxy resin. The first prepreg is then placed on a first copper layer. A second copper layer is then placed on a top surface of the first prepreg. A basalt fiber core is placed on the second copper layer. In an example, the basalt fiber core includes a basalt fiber prepreg and two copper layers. A third copper layer is placed on the top surface of the basalt fiber core. A second prepreg is also dipped in the epoxy resin and then placed on the top surface of the third copper layer. In an example, the second prepreg includes a basalt fiber fabric and an epoxy resin. A fourth copper layer is then placed on the top surface of the second prepreg. The basalt fiber core, the first prepreg, the second prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer are then compressed to form the PCB.

[0011] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Non-limiting and non-exhaustive examples are described with reference to the following figures.

[0013] Figure 1 A basalt fiber core for a PCB according to an example is shown.

[0014] Figure 2 A basalt fiber fabric-based PCB according to an example is shown.

[0015] Figure 3 A method of preparing an epoxy resin mixture according to an example is shown.

[0016] Figure 4 A method of manufacturing a basalt fiber prepreg according to an example is shown.

[0017] Figure 5 A method of manufacturing a basalt fiber core for a printed circuit board according to an example is shown.

[0018] Figure 6 A method of manufacturing a multilayer printed circuit board according to an example is shown. DETAILED DESCRIPTION

[0019] In the following detailed description, reference is made to the accompanying drawings, which form a part of the present invention and in which specific embodiments or examples are shown by way of illustration. Aspects may be combined, other aspects may be utilized, and structural changes may be made without departing from the present disclosure. Therefore, the following detailed description should not be construed in a restrictive sense, and the scope of the present disclosure is limited only by the appended claims and their equivalents.

[0020] Woven-glass-based printed circuit boards (PCBs), also known as FR4 PCBs, are commonly used in a variety of electronic devices. Woven-glass-based PCBs have excellent electrical and mechanical properties, which contribute to the overall reliability and performance of the electronic device.

[0021] However, due to the manufacturing process and materials used to make PCBs, glass fiber fabric-based PCBs have significant environmental impacts. For example, the production of glass fibers involves an energy-intensive process. In addition, the raw materials (e.g., silica sand, chemicals) used to produce glass fibers are non-renewable resources. The manufacturing process also emits large amounts of carbon dioxide.

[0022] In addition to the disadvantages listed above, PCBs based on glass fabric also generate waste during end-of-life processing. For example, due to the complex composition of glass fiber and epoxy resin, it is challenging to recycle and / or properly dispose of PCBs based on glass fabric, which leads to the accumulation of electronic waste.

[0023] To address the above problems, the present application describes a PCB manufactured using naturally occurring materials. In an example, the naturally occurring material is basalt fiber derived from naturally occurring volcanic rocks. The basalt fiber can then be used to make basalt fiber fabrics. Because basalt fiber is derived from naturally occurring materials, it is more sustainable and environmentally friendly than glass fiber. In addition, basalt fiber is stable, inert, sustainable and non-reactive.

[0024] Other advantages of using basalt fibers instead of glass fibers are: basalt fibers have high mechanical physicochemical properties, basalt fibers are biodegradable, easily recyclable, non-chemically reactive, non-toxic with air and / or water, and basalt fibers have non-abrasive qualities. In addition, basalt fibers have better mechanical properties compared to glass fibers, have high temperature resistance and high corrosion resistance.

[0025] In addition to the environmental benefits of using basalt fiber in the manufacture of PCBs, PCBs based on basalt fiber fabrics also provide many technical benefits, including but not limited to making the PCB more resistant to breakage, bending and other mechanical stresses. PCBs based on basalt fiber fabrics also have low dielectric constant variations with frequency, temperature and moisture content, which helps maintain signal integrity and reduces the risk of signal distortion or loss. Compared to glass fiber, basalt fiber has better radio frequency (RF) shielding and electromagnetic interference (EMI) protection. In addition, PCBs based on basalt fiber fabrics can effectively block or weaken RF signals, which minimizes interference and ensures reliable performance of sensitive electronic components. Basalt fiber also exhibits good resistance to chemicals and corrosive environments, which enables PCBs based on basalt fiber fabrics to withstand exposure to various substances. Compared with glass fiber fabrics, basalt fiber fabrics are also easier to form into complex shapes. As a result, basalt fiber fabrics allow greater design flexibility in PCB manufacturing. As a result, customized and complex PCB layouts can be designed and produced based on specific application requirements.

[0026] About Figure 1-Figure 6 These and other examples are shown and described in further detail.

[0027] Figure 1 A basalt fiber core 100 for a PCB according to an example is shown. As previously explained, due to the excellent thermal properties of basalt fiber, the basalt fiber core 100 can be used in low temperature applications as well as high temperature applications.

[0028] In an example, the basalt fiber core 100 includes a basalt fiber prepreg 110, a first copper layer 120, and a second copper layer 130. The basalt fiber prepreg 110 includes a basalt fiber fabric and an epoxy resin. In an example, the basalt fiber fabric is made of basalt fibers. The basalt fiber fabric may have a variety of different configurations or weaving forms. For example, the basalt fiber fabric may have a plain weave pattern, a twill weave pattern, a biaxial weave pattern, a triaxial weave pattern, etc. In addition, in an example, the basalt fiber prepreg may include a single layer of basalt fiber fabric or multiple layers of basalt fiber fabric. In an example, glass fiber is not used to produce the basalt fiber core 100 and / or the basalt fiber fabric-based PCB of which the basalt fiber core 100 will be a part.

[0029] In an example, during the manufacture of the basalt fiber core 100, the basalt fiber prepreg is impregnated with epoxy resin. The first copper layer 120 and the second copper layer 130 are coupled to the first surface and the second surface of the basalt fiber prepreg 110. Figure 5 Explaining in more detail, the copper layer and basalt fiber prepreg are compression cured and then cooled. The basalt fiber core 100 can then be used to manufacture a basalt fiber fabric-based PCB.

[0030] Figure 2 2 shows a PCB 200 based on basalt fiber fabric according to an example. The PCB 200 based on basalt fiber fabric includes a basalt fiber core 210 and a plurality of basalt fiber prepregs. In the example, the basalt fiber core 210 is similar to the basalt fiber prepreg described in detail. Figure 1 The basalt fiber core 100 shown and described. Thus, the basalt fiber core 210 includes a first copper layer 120 and a second copper layer 130 (eg, a first copper layer 120 and a second copper layer 130) sandwiched or provided between two copper layers. Figure 1 )) between the basalt fiber prepreg (for example, the basalt fiber prepreg 110 ( Figure 1 )).

[0031] In the example shown, the basalt fiber fabric-based PCB 200 is a four-layer PCB. Although four layers are shown, the basalt fiber fabric-based PCB 200 may include any number of layers. In addition, each of the layers may be formed using the various processes described herein.

[0032] In an example, the basalt fiber fabric-based PCB 200 includes a first copper layer 220, a first basalt fiber prepreg 230, and a second copper layer 240. The first copper layer 220 is adhered, attached, or otherwise coupled to the bottom surface of the first basalt fiber prepreg 230. Similarly, the second copper layer 240 is adhered, attached, or otherwise coupled to the top surface of the first basalt fiber prepreg 230.

[0033] The basalt fiber core 210 is adhered, attached, or otherwise coupled to the top surface of the second copper layer 240. For example, the second copper layer (eg, the second copper layer 130 ( Figure 1 The bottom surface of )) is coupled to the top surface of the second copper layer 240.

[0034] In addition, the third copper layer 250 is adhered, attached, or otherwise coupled to the top surface of the basalt fiber core 210. For example, the first copper layer (eg, the first copper layer 120 ( Figure 1 )) is coupled to the bottom surface of the third copper layer 250. In an example, the basalt fiber fabric-based PCB 200 further includes a second basalt fiber prepreg 260 adhered, attached, or otherwise coupled to the top surface of the third copper layer 250. The fourth copper layer 270 is also adhered, attached, or otherwise coupled to the top surface of the second basalt fiber prepreg 260.

[0035] In an example, a PCB 200 based on basalt fiber fabric provides many environmental advantages over a PCB based on glass fiber fabric. For example and as previously explained, basalt fibers are derived from volcanic rocks, which are a natural and abundant resource. Additionally, the production of basalt fibers and basalt fiber fabrics requires less energy than the production of glass fibers and glass fiber fabrics, which results in a lower environmental impact during production. The production of basalt fibers emits less carbon dioxide than glass fibers.

[0036] Because basalt is a naturally occurring rock, lower temperatures are required to convert basalt to fiber compared to glass fiber conversion, which reduces energy consumption and associated carbon dioxide emissions. Basalt fiber fabrics are also more eco-friendly in terms of waste generation. Basalt fibers are also naturally resistant to moisture and degradation, which can result in longer product life. In addition, basalt fiber-based materials can be more easily recycled and reused than glass fiber-based materials.

[0037] In addition to various environmental benefits, PCBs based on basalt fiber fabrics have similar and in some cases better physical, mechanical, thermal, and electrical properties than PCBs based on glass fiber fabrics. For illustration, a four-layer glass fiber fabric-based PCB and a four-layer basalt fiber fabric-based PCB were produced under the same conditions and using the same epoxy resin. Table 1 shows the physical, mechanical, thermal, and electrical properties of a four-layer glass fiber fabric-based PCB compared to the same physical, mechanical, thermal, and electrical properties of a four-layer basalt fiber fabric-based PCB 200. A detailed explanation of Table 1 is as follows.

[0038]

[0039]

[0040] Table 1

[0041] The density of a PCB is an important factor to consider during the design and fabrication phase of a PCB because density can affect signal integrity. For example, higher density can reduce the amount of electromagnetic interference and signal crosstalk, which can result in better performance and reliability. Additional factors that affect the density of a PCB can include the number of layers in the PCB, the thickness of the copper traces, and the type of material from which the PCB is made.

[0042] As shown in Table 1, the PCB 200 based on basalt fiber fabric has a higher density than the PCB based on glass fiber fabric. For example, the density of the PCB 200 based on basalt fiber fabric is 1.9 g / cm3. 3 ) and 2.3g / cm 3 In contrast, the density of glass fiber fabric-based PCBs is between 1.5 g / cm 3 and 1.8g / cm 3 between.

[0043] Table 1 also shows that the PCB 200 based on basalt fiber fabric has a higher elastic modulus than the PCB based on glass fiber fabric. High modulus materials have a higher resistance to deformation under stress than lower modulus materials. Therefore, the higher the modulus, the more structurally stable the PCB will be. As a result, the PCB will not deform or bend excessively under the weight of the components, during handling, or when exposed to vibration or mechanical stress. High modulus materials also help maintain the dimensional stability of the PCB, which is critical for the various electronic components mounted on or otherwise associated with the PCB to function reliably.

[0044] For example, the elastic modulus of the PCB 200 based on basalt fiber fabric is between 6.0 GPa and 9.0 GPa, while the PCB based on glass fiber fabric has an elastic modulus between 1.0 GPa and 3.5 GPa. In addition, the tensile strength of the PCB 200 based on basalt fiber fabric is between 130 MPa and 175 MPa, while the tensile strength of the PCB based on glass fiber fabric is between 30 MPa and 50 MPa.

[0045] The coefficient of thermal expansion (CTE) is a property that indicates how much a material expands when heated. During temperature fluctuations, solder joints on a PCB expand and contract. If the CTE of the PCB does not match the CTE of the solder joint and / or the CTE of the various components on the PCB, this can create mechanical stress on the solder joint. This can lead to solder fatigue and ultimately solder joint failure.

[0046] As shown in Table 1, the X-axis CTE of the glass fiber fabric-based PCB is between 14 parts per million per degree Celsius (14 ppm / ° C.) and 18 ppm / ° C., and the Y-axis CTE of the glass fiber fabric-based PCB is between 14 ppm / ° C. and 18 ppm / ° C. The X-axis CTE of the basalt fiber fabric-based PCB 200 is between 12 ppm / ° C. and 18 ppm / ° C., and the Y-axis CTE of the basalt fiber fabric-based PCB 200 is between 15 ppm / ° C. and 19 ppm / ° C. Therefore, the CTE of the basalt fiber fabric-based PCB 200 is comparable to that of the glass fiber fabric-based PCB.

[0047] Thermal conductivity is a fundamental property of PCBs. Thermal conductivity is the ability of a PCB to effectively and efficiently dissipate the heat generated by active components on the PCB (e.g., processors, transistors, power components). Heat dissipation prevents overheating, which can cause performance issues, premature component failure, or even fire hazards. Thermal conductivity is primarily affected by the materials used in the core and prepreg layers.

[0048] As shown in Table 1, the thermal conductivity of the glass fiber fabric-based PCB is between 2.5 Watts per meter per Kelvin (W / m·K) and 3.1 W / m·K. The thermal conductivity of the basalt fiber fabric-based PCB 200 is between 2.5 W / m·K and 3.2 W / m·K. Since these values ​​are substantially similar, replacing glass fiber with basalt fiber does not cause any thermal and / or reliability issues to the PCB.

[0049] Table 1 also shows that when the temperature exceeds the glass transition temperature (Tg) threshold, the CTE of the glass fiber fabric-based PCB and the CTE of the basalt fiber fabric-based PCB 200 are substantially similar. For example, the Tg of the glass fiber fabric-based PCB is between 165°C and 170°C, while the Tg of the basalt fiber fabric-based PCB 200 is between 166°C and 172°C. When the Tg of a material exceeds 170°C, the material is referred to as a high Tg material. As the Tg of a material increases, the heat resistance, moisture resistance, chemical resistance and stability of the material are enhanced. In addition, the thermal degradation temperature of the glass fiber fabric-based PCB and the thermal degradation temperature of the basalt fiber fabric-based PCB 200 are substantially similar. For example, the thermal degradation temperature of the basalt fiber fabric-based PCB 200 at 1% weight loss is between 205°C and 220°C, while the thermal degradation temperature of the glass fiber fabric-based PCB 200 at 1% weight loss is between 210°C and 220°C. Therefore, the higher the Tg value and thermal degradation temperature, the better the temperature resistance of the material. In addition, basalt fiber is a high temperature resistant material, and basalt fiber can be used in high temperature applications.

[0050] The two most important factors that determine electrical properties are impedance and signal integrity. The speed at which electrical signals propagate through a PCB material is determined by the dielectric constant of the PCB material. The higher the dielectric constant, the slower the signal speed, while the lower the dielectric constant, the faster the signal speed. Therefore, PCB materials with low dielectric constants work more efficiently.

[0051] Typically, the dielectric constant or relative dielectric constant of PCB materials is between 3.5 and 5.5. As shown in Table 1, the dielectric constant (Dk) of the glass fiber fabric-based PCB at 1 gigahertz (GHZ) is between 4.5 and 5.5, while the dielectric constant of the basalt fiber fabric-based PCB 200 at 1 GHz is between 4.7 and 5.8. Thus, the dielectric constant of the basalt fiber fabric-based PCB 200 is well within the expected dielectric constant range.

[0052] If the loss tangent of a material is low, the material loses less power. Typically, the dielectric loss tangent (Tanδ) of materials used in PCBs is in the range of 0.02 to 0.001. As shown in Table 1, the dielectric loss tangent of the PCB 200 based on basalt fiber fabric is between 0.015 and 0.030, while the dielectric loss tangent of the PCB based on glass fiber fabric is between 0.015 and 0.025. This indicates good signal integrity in the PCB 200 based on basalt fiber fabric. In addition, because there is no large deviation in the Dk and Df values ​​between the PCB 200GF based on basalt fiber fabric and the PCB based on glass fiber fabric, the PCB based on basalt fiber fabric can be used instead of the PCB based on glass fiber fabric.

[0053] Figure 3 A method 300 of preparing an epoxy resin mixture according to an example is shown. In an example, the epoxy resin mixture is combined with basalt fiber or basalt fiber fabric to produce, manufacture or fabricate a basalt fiber prepreg and / or a basalt fiber core, for example, Figure 1 The basalt fiber core 100 shown and described. In addition, the epoxy resin mixture can be used to manufacture multi-layer PCBs, such as Figure 2 The basalt fiber fabric based PCB 200 and the like are shown and described.

[0054] Method 300 begins when an epoxy resin is combined with a hardener (310). For example, between 28 gm and 55 gm of a solid epoxy resin (e.g., HP6000 or other naphthyl epoxy resin) is mixed with between 22 gm and 45 gm of a phenol-based hardener based on a ratio of 1.22:1. In an example, a phenol-based hardener is used in combination with a naphthyl epoxy resin due to their compatibility. For example, the combination of a phenol-based hardener and a naphthyl epoxy resin helps ensure a strong cross-linking reaction and network structure that provide specific characteristics to the cured epoxy resin. When these materials are combined, the materials provide a cured epoxy resin system with excellent thermal stability, which helps ensure that the material is suitable for high temperature applications. In addition, when compared to other resins and hardeners, these materials can provide improved mechanical properties, such as increased rigidity and tensile strength.

[0055] Although specific weights and ratios of epoxy resin to hardener are mentioned, the epoxy resin mixture can be mixed with the hardener using a ratio between 0.9 and 1.4 (epoxy resin) and between 0.8 and 1.2 (hardener). In addition, although solid epoxy resins are specifically mentioned, it is contemplated that the epoxy resin can be any type of epoxy resin, including but not limited to solid epoxy resins, liquid epoxy resins, single components, two components, epoxy resins with all filler types, epoxy resins with high Tg, and epoxy resins with low Tg. In addition, although phenol-based hardeners are specifically mentioned, amine-based hardeners or other types of hardeners can be used. When the epoxy resin and hardener are combined, a promoter is added (320) to the mixture. In an example, the promoter is 2-ethyl-4-methylimidazole (EMI24). EMI24 is an effective curing agent and promoter. EMI24 promotes a high degree of crosslinking, accelerates polymerization, and provides a fast cure rate, which reduces the total cure time compared to other promoters. Although EMI24 is specifically mentioned, other accelerators (e.g., triphenylphosphine or imidazole based accelerators) may be used. The amount of accelerator added is between 1 gm and 5 gm. The accelerator is used to speed up the curing time of the epoxy resin.

[0056] Solvent is then added (330) to the epoxy, hardener and accelerator mixture. In an example, the amount of solvent added to the mixture is between 50 gm and 70 gm. All materials are then mixed (340) to produce an epoxy mixture.

[0057] In the examples, the solvent is methyl ethyl ketone (MEK). Although MEK is specifically mentioned, other solvents (e.g., toluene, methyl cellosolve, acetone, methoxypropanol) may be used. In the examples, MEK is used because it has a moderate evaporation rate and boiling point compared to other solvents. For example, when MEK is compared to acetone, acetone evaporates faster, which can significantly shorten the working time when mixing and applying the epoxy resin to the basalt fiber fabric or basalt fiber prepreg. In contrast, MEK does not evaporate as quickly as acetone, which helps ensure that the desired viscosity of the epoxy resin mixture is maintained throughout the mixing and coating process (described below). In addition, MEK has excellent solubility in the resin and helps ensure a consistent and uniform mixture.

[0058] When comparing MEK to other solvents with slower evaporation rates (e.g., toluene, methyl cellosolve), the slower evaporation rate may not be as efficient during the compression curing process (described below). At its moderate evaporation rate and boiling point, MEK can evaporate within the time frame specified by the compression curing process.

[0059] In an example, a magnetic stirrer is used to uniformly mix the material for about 10 to 15 minutes at different RPM conditions (e.g., 450 RPM-1200 RPM). Although a specific amount of time is specified, the material is mixed until the solid epoxy resin is completely dissolved and becomes a liquid form.

[0060] In an example, any type of epoxy resin, hardener, accelerator, solvent used in the PCB industry can be used to create an epoxy resin mixture for basalt fiber fabric based PCBs. Table 2 contains the materials used for the epoxy resin mixture, with respect to ratios (R) and weights (W).

[0061] Chemicals Ratio (R) and Weight (W) Epoxy resin 0.9-1.4(R) Hardener 0.8-1.2(R) Accelerator 1-5gm(W) Solvents 50-70gm(W)

[0062] Table 2

[0063] Figure 4 A method 400 for manufacturing a basalt fiber prepreg according to an example is shown. In an example, the method 400 can be used to manufacture, produce, or otherwise make a basalt fiber prepreg, which can be used as a basalt fiber core (e.g., basalt fiber core 100 ( Figure 1 )) and / or basalt fiber fabric-based PCB (e.g., basalt fiber fabric-based PCB 200 ( Figure 2 )). In addition, and in an example, method 400 may be performed after the epoxy resin mixture has been prepared (eg, after method 300 ( Figure 3 ) occurs after ).

[0064] Method 400 begins when a basalt fiber fabric (including basalt fibers) is dried (410) or otherwise subjected to a drying process. The drying process is used to remove any moisture that may be contained within the basalt fiber fabric. In an example, the drying process includes placing the basalt fiber fabric in an oven (or other drying / heating device) and drying / heating the basalt fibers at a specific temperature for a period of time. Although an oven is specifically mentioned, the basalt fiber fabric can be dried by oven drying, hot air drying, directional assisted hot air drying, and / or short wave drying, or a combination thereof. In an example, the basalt fiber fabric is dried at a temperature between 70° C. and 100° C. for between thirty minutes and one hour.

[0065] After the drying process is completed, the basalt fiber fabric is impregnated (420) with epoxy resin. In an example, the basalt fiber fabric is impregnated with epoxy resin using one or more of dip coating, air spraying, airless spraying, slot die coating, immersion, ultrasonic coating, 3D printing, roller coating, paint brush, electrostatic spraying, or high volume low pressure (HVLP) spraying. In an example, the basalt fiber fabric is impregnated with epoxy resin using Figure 3 The method 300 shown and described produces an epoxy resin mixture that impregnates a basalt fiber fabric.

[0066] After the basalt fibers are removed from the epoxy resin mixture, the basalt fibers are compression cured using a compression curing process (430). In an example, the basalt fibers and epoxy resin are compression cured at a temperature between 170° C. and 175° C. and a pressure between 1 MPa and 10 MPa for three to five minutes. In an example, an oven and / or a hot press is used for the compression curing process. The compression curing process helps ensure that the epoxy resin is evenly distributed on the basalt fiber fabric.

[0067] The basalt fiber fabric and epoxy resin are cooled and compressed at the same time (440). In an example, the basalt fiber fabric is cooled with water and compressed at a pressure between 1 MPa and 10 MPa for three to five minutes. After the compression and cooling process is completed, a basalt fiber prepreg is manufactured / produced.

[0068] Figure 5 A method 500 for manufacturing a basalt fiber core for a PCB according to an example is shown. In an example, the method 500 can be used to manufacture a basalt fiber core for a PCB. Figure 1 The basalt fiber core 100 shown and described. In addition, the epoxy resin used in the method 500 may be used in conjunction with Figure 3 The epoxy resin mixture produced by the method 300 shown and described. In another example, a basalt fiber prepreg used as part of a basalt fiber core may be used with respect to Figure 4 The method 400 is shown and described for manufacturing.

[0069] The method 500 begins by drying (510) the manufactured basalt fiber prepreg to remove any moisture. In an example, the drying process includes, but is not limited to, oven drying, hot air drying, directional assisted hot air drying, and / or short wave drying, or a combination thereof. The basalt fiber prepreg is dried at a specific temperature for a specific period of time. In an example, the basalt fiber prepreg is dried at a temperature between 70° C. and 100° C. for between thirty minutes and one hour.

[0070] After the drying process is completed, the basalt fiber prepreg is impregnated (520) with epoxy resin. In an example, the basalt fiber prepreg is impregnated with epoxy resin, including but not limited to one or more of the following methods: dip coating, air spraying, airless spraying, slot die coating, immersion, ultrasonic coating, 3D printing, roller coating, paint brush, electrostatic spraying and high volume low pressure (HVLP) spraying. In an example, the basalt fiber prepreg is impregnated with an epoxy resin mixture, and the epoxy resin mixture is used for Figure 3 The method 300 shown and described produces Impregnation of the basalt fiber prepreg with epoxy resin facilitates adhering, attaching, bonding or otherwise securing the copper layer to the basalt fiber prepreg.

[0071] After removing the basalt fiber prepreg from the epoxy resin mixture, a first copper layer is placed (530) on a first surface of the basalt fiber prepreg, and a second copper layer is placed on a second surface of the basalt fiber prepreg. The basalt fiber prepreg and the copper layers are compression cured (540) using a compression curing process.

[0072] In an example, the basalt fiber prepreg and copper layer are compression cured at a temperature between 170° C. and 175° C. at a pressure between 1 MPa and 10 MPa for three to five minutes. In an example, an oven and / or hot press equipment is used for the compression curing process.

[0073] The basalt fiber prepreg and copper layer are cooled and compressed (550) using a compression cooling process. In an example, the basalt fiber prepreg and copper layer are cooled with water and compressed at a pressure between 1 MPa and 10 MPa for three to five minutes. After the compression cooling process is completed, a basalt fiber core is manufactured / produced.

[0074] Figure 6 A method 600 for manufacturing a multilayer PCB according to an example is shown. In an example, the method 600 can be used to manufacture a multilayer PCB. Figure 2 The multi-layer basalt fiber fabric-based PCB 200 shown and described. In addition, the epoxy resin used in method 600 may be a Figure 3 The epoxy resin mixture produced by the method 300 shown and described. Basalt fiber prepreg and / or basalt fiber core used to manufacture a multi-layer basalt fiber fabric-based PCB can be used with respect to Figure 4 The method 400 shown and described and / or with respect to Figure 5 The method 500 is shown and described for manufacturing.

[0075] The method 600 begins by drying (605) the manufactured basalt fiber core to remove any moisture. Similarly, one or more basalt fiber prepregs are also dried (610) to remove any moisture. In an example, the drying process includes various drying processes previously described. In an example, the basalt fiber core and / or basalt fiber prepreg are dried at a temperature between 70° C. and 100° C. for between thirty minutes and one hour.

[0076] After the drying process is complete, the first basalt fiber prepreg is impregnated 615 with epoxy resin. In an example, the first basalt fiber prepreg is impregnated with epoxy resin using various coating / impregnation processes previously described. In an example, the first basalt fiber prepreg is impregnated with the epoxy resin mixture produced using method 300. Impregnating the first basalt fiber prepreg with epoxy resin helps adhere, attach, bond, or otherwise secure the copper layer to the first basalt fiber prepreg.

[0077] After removing the basalt fiber prepreg from the epoxy resin mixture, a first basalt fiber prepreg is placed (620) on the first copper layer. A second copper layer is then placed (625) on the top surface of the first basalt fiber prepreg. A basalt fiber core is then placed (630) on the top surface of the second copper layer. A third copper layer may then be placed (635) on the top surface of the basalt fiber core.

[0078] The second basalt fiber prepreg may then be impregnated 640 with epoxy resin. In an example, the second basalt fiber prepreg is impregnated with epoxy resin using various coating / impregnation processes previously described. In an example, the second basalt fiber prepreg is impregnated with the epoxy resin mixture produced using method 300. Impregnating the second basalt fiber prepreg with epoxy resin facilitates adhering, attaching, bonding, or otherwise securing the copper layer to the second basalt fiber prepreg.

[0079] After removing the second basalt fiber prepreg from the epoxy resin mixture, the second basalt fiber prepreg is placed (645) on the top surface of the third copper layer.The fourth copper layer is then placed (650) on the top surface of the second basalt fiber prepreg.

[0080] The structure (e.g., the first copper layer, the first basalt fiber prepreg, the second copper layer, the basalt fiber core, the third copper layer, the second basalt fiber prepreg, and the fourth copper layer) is compression cured (655) using a compression curing process. In an example, the structure is compression cured at a temperature between 170° C. and 175° C. and a pressure between 1 MPa and 10 MPa for three to five minutes. In an example, an oven and / or a hot press is used for the compression curing process.

[0081] The structure is then cooled and compressed (660) using a compression cooling process. In an example, the structure is cooled with water and compressed at a pressure between 1 MPa and 10 MPa for three to five minutes.

[0082] Based on the above, an example of the present disclosure describes a printed circuit board (PCB), which includes: a basalt fiber core, the basalt fiber core including: a first prepreg including basalt fiber and epoxy resin; a first copper layer coupled to a first surface of the first prepreg; and a second copper layer coupled to a second surface of the first prepreg; a third copper layer coupled to the first copper layer; a fourth copper layer coupled to the second copper layer; a second prepreg coupled to the third copper layer, the second prepreg including basalt fiber and epoxy resin; and a third prepreg coupled to the fourth copper layer, the third prepreg including basalt fiber and epoxy resin. In an example, the PCB also includes a fifth copper layer coupled to the second prepreg and a sixth copper layer coupled to the third prepreg. In an example, the first copper layer and the second copper layer are coupled to the first surface of the first prepreg and the second surface of the first prepreg during a compression curing process. In an example, the elastic modulus of the PCB is between 6.0 GPa and 9.0 GPa. In an example, the PCB has a coefficient of thermal expansion (CTE) between 12 parts per million per degree Celsius (12 ppm / °C) and 18 ppm / °C in a first axis and a CTE between 15 ppm / °C and 19 ppm / °C in a second axis. In an example, the PCB has a CTE between 1.9 grams per cubic centimeter (g / cm 3 ) and 2.3g / cm 3 , and wherein the PCB has a thermal conductivity between 2.5 Watts per meter per Kelvin (W / m·K) and 3.2 W / m·K. In an example, the PCB has a dielectric constant between 4.7 and 5.8 at 1 GHz.

[0083] Other examples describe a method of manufacturing a basalt fiber prepreg for a printed circuit board (PCB), the method comprising: drying a basalt fiber fabric; impregnating the basalt fiber fabric with an epoxy resin; compressing and curing the basalt fiber fabric and the epoxy resin; and cooling the basalt fiber fabric and the epoxy resin. In an example, drying the basalt fiber fabric comprises drying the basalt fiber fabric at a temperature between 70°C and 100°C for thirty to sixty minutes. In an example, impregnating the basalt fabric with an epoxy resin comprises one or more processes selected from the following process groups, including: dip coating, spray coating, slot die coating, immersion, ultrasonic coating, three-dimensional printing, roller coating, paint brush, electrostatic spraying, or high volume low pressure (HVLP) spraying. In an example, compressing and curing the basalt fiber fabric comprises compressing and curing the basalt fiber fabric at a temperature between 170°C and 175°C at a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes. In an example, cooling the basalt fiber fabric includes water cooling the basalt fiber fabric while applying a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes.

[0084] Yet other examples describe a method of manufacturing a printed circuit board (PCB), the method comprising: impregnating a first basalt fiber prepreg with epoxy resin; placing the first basalt fiber prepreg on a first copper layer; placing a second copper layer on a top surface of the first basalt fiber prepreg; placing a basalt fiber core on the second copper layer; placing a third copper layer on a top surface of the basalt fiber core; impregnating a second basalt fiber prepreg with epoxy resin; placing the second basalt fiber prepreg on a top surface of the third copper layer; placing a fourth copper layer on a top surface of the second basalt fiber prepreg; and compressing the basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer. In an example, compressing the basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer includes compression curing the basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer at a temperature between 170° C. and 175° C. and a pressure between 1 megapascal (MPa) and 10 MPa for three to ten minutes. In an example, the method further includes cooling the compressed basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer. In an example, cooling the compressed basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer includes water cooling the compressed basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer while applying a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes. In an example, manufacturing the first basalt fiber prepreg and the second basalt fiber prepreg includes: drying a basalt fiber fabric; impregnating the basalt fiber fabric with an epoxy resin; compressing and curing the basalt fiber fabric; and cooling the basalt fiber fabric. In an example, drying the basalt fiber fabric includes drying the basalt fiber fabric at a temperature between 70° C. and 100° C. for thirty to sixty minutes. In an example, compressing and curing the basalt fiber fabric includes compressing and curing the basalt fiber fabric at a temperature between 170° C. and 175° C. and a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes. In an example, cooling the basalt fiber fabric includes water cooling the basalt fiber fabric while applying a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes.

[0085] The description and illustration of one or more aspects provided in this disclosure are not intended to limit or restrict the scope of this disclosure in any way. The various aspects, examples and details provided in this disclosure are considered sufficient to convey the property and enable others to make and use the best mode of the claimed disclosure.

[0086] The disclosure required should not be construed as being limited to any aspect, example or detail provided in the present disclosure. Whether in combination or individually displayed and described, various features (structures and methods) are intended to be selectively rearranged, included or omitted to produce an embodiment with a specific feature set. After the description and illustration of the present application have been provided, those skilled in the art may envision changes, modifications and alternative aspects within the spirit of the broader aspects of the general inventive concept embodied in the present application, which changes, modifications and alternative aspects do not depart from the broader scope of the disclosure required.

[0087] Aspects of the present disclosure have been described above with reference to schematic flow charts and / or schematic block diagrams of the methods, devices, systems, and computer program products according to embodiments of the present disclosure. It should be understood that each frame of the schematic flow charts and / or schematic block diagrams, as well as the combination of frames in the schematic flow charts and / or schematic block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor or other programmable data processing device of a computer to produce a machine, so that instructions executed via a processor or other programmable data processing device create components for implementing the functions and / or actions specified in the frames of one or more schematic flow charts and / or schematic block diagrams. In addition, it is contemplated that various aspects of the flow charts and / or flow charts can be combined and / or executed in any order.

[0088] Reference to elements using designations such as "first," "second," etc. herein generally does not limit the number or order of those elements. In fact, these designations can be used as a method of distinguishing two or more elements or instances of elements. Thus, reference to a first and a second element does not mean that only two elements can be used, or that the first element precedes the second element. Additionally, unless otherwise stated, a collection of elements may include one or more elements.

[0089] A term of the form "at least one of A, B, or C" or "A, B, C, or any combination thereof" used in the specification or claims means "A or B or C, or any combination of these elements." For example, this term may include A or B or C, or A and B, or A and C, or A and B and C, or 2A, or 2B, or 2C, or 2A and B, etc. As an additional example, "at least one of: A, B, or C" is intended to cover A, B, C, AB, AC, BC, and ABC, and multiples of the same member. Similarly, "at least one of: A, B, and C" is intended to cover A, B, C, AB, AC, BC, and ABC, and multiples of the same member.

[0090] Similarly, as used herein, a phrase referring to a list of items in connection with "and / or" refers to any combination of the items. As an example, "A and / or B" is intended to cover A alone, B alone, or A and B together. As another example, "A, B, and / or C" is intended to cover A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together.

Claims

1. A printed circuit board (PCB), comprising: Basalt fiber core, comprising: a first prepreg including basalt fiber and epoxy resin; a first copper layer coupled to the first surface of the first prepreg; and a second copper layer coupled to the second surface of the first prepreg; a third copper layer coupled to the first copper layer; a fourth copper layer coupled to the second copper layer; a second prepreg coupled to the third copper layer, the second prepreg comprising basalt fiber and epoxy resin; and A third prepreg is coupled to the fourth copper layer, the third prepreg comprising basalt fiber and epoxy resin. 2 . The PCB of claim 1 , further comprising a fifth copper layer coupled to the second prepreg and a sixth copper layer coupled to the third prepreg. 3 . The PCB of claim 1 , wherein the first copper layer and the second copper layer are coupled to the first surface of the first prepreg and the second surface of the first prepreg during a compression curing process.

4. The PCB of claim 1, wherein an elastic modulus of the PCB is between 6.0 GPa and 9.0 GPa.

5. The PCB of claim 1, wherein the PCB has a coefficient of thermal expansion (CTE) between 12 parts per million per degree Celsius (12 ppm / °C) and 18 ppm / °C in a first axis, and has a CTE between 15 ppm / °C and 19 ppm / °C in a second axis.

6. The PCB according to claim 1, wherein the PCB has a relative humidity of 1.9 g / cm3. 3 ) and 2.3g / cm 3 , and wherein the PCB has a thermal conductivity between 2.5 Watts per meter per Kelvin (W / m·K) and 3.2 W / m·K.

7. The PCB of claim 1, wherein the dielectric constant of the PCB at 1 GHz is between 4.7 and 5.

8.

8. A method for manufacturing a basalt fiber prepreg for a printed circuit board (PCB), comprising: Drying basalt fiber fabrics; impregnating the basalt fiber fabric with epoxy resin; compressing and curing the basalt fiber fabric and the epoxy resin; as well as The basalt fiber fabric and the epoxy resin are cooled.

9. The method of claim 8, wherein drying the basalt fiber mat comprises drying the basalt fiber mat at a temperature between 70°C and 100°C for thirty to sixty minutes.

10. The method of claim 8, wherein impregnating the basalt fabric with the epoxy resin comprises one or more processes selected from the following group of processes, comprising: Dip coating, spray coating, slot die coating, immersion, ultrasonic coating, 3D printing, roller coating, paint brush, electrostatic spray and high volume low pressure (HVLP) spray.

11. The method of claim 8, wherein compression curing the basalt fiber mat comprises compression curing the basalt fiber mat at a temperature between 170°C and 175°C and a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes.

12. The method of claim 8, wherein cooling the basalt fiber fabric comprises water cooling the basalt fiber fabric while applying a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes.

13. A method of manufacturing a printed circuit board (PCB), comprising: impregnating a first basalt fiber prepreg with an epoxy resin; placing the first basalt fiber prepreg on the first copper layer; placing a second copper layer on a top surface of the first basalt fiber prepreg; placing a basalt fiber core on the second copper layer; placing a third copper layer on the top surface of the basalt fiber core; impregnating a second basalt fiber prepreg with epoxy resin; placing the second basalt fiber prepreg on a top surface of the third copper layer; placing a fourth copper layer on the top surface of the second basalt fiber prepreg; as well as The basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer are compressed.

14. The method of claim 13, wherein compressing the basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer comprises compression curing the basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer at a temperature between 170° C. and 175° C. and a pressure between 1 megapascal (MPa) and 10 MPa for three to ten minutes.

15. The method of claim 13, further comprising cooling the compressed basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer.

16. The method of claim 15, wherein cooling the compressed basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer comprises water cooling the compressed basalt fiber core, the first basalt fiber prepreg, the second basalt fiber prepreg, the first copper layer, the second copper layer, the third copper layer, and the fourth copper layer while applying a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes.

17. The method according to claim 13, wherein manufacturing the first basalt fiber prepreg and the second basalt fiber prepreg comprises: Drying basalt fiber fabrics; impregnating the basalt fiber fabric with the epoxy resin; compressing and curing the basalt fiber fabric; as well as The basalt fiber fabric is cooled.

18. The method of claim 17, wherein drying the basalt fiber mat comprises drying the basalt fiber mat at a temperature between 70°C and 100°C for thirty to sixty minutes.

19. The method of claim 17, wherein compression curing the basalt fiber mat comprises compression curing the basalt fiber mat at a temperature between 170°C and 175°C and a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes.

20. The method of claim 17, wherein cooling the basalt fiber fabric comprises water cooling the basalt fiber fabric while applying a pressure between 1 megapascal (MPa) and 10 MPa for three to five minutes.

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