PCB boards are widely used in the electronics industry, as one of the important components of electronic equipment, aiming for connecting various electronic components. The performance of PCB boards directly affects the quality and stability of electronic devices. The material selection of the PCB board is one of the key factors affecting the performance of the PCB board. This article will compare and analyze common PCB materials in order to select suitable materials for different board designs.
Classification of the PCB materials
According to the needs of different applications, the material types of PCB are also different. At present, common PCB materials are mainly divided into the following categories:
Silicon carbide materials
Silicon carbide materials have relatively high thermal conductivity, which is ideal for circuit boards with relatively high temperatures, such as automotive electronics, aerospace electronics and other fields, and silicon carbide materials also have the advantages of high temperature resistance and low energy consumption. However, the cost of silicon carbide materials is relatively high, and the hardness is relatively large, which is not easy to process.
FR-4 material is one of the most common PCB materials and is widely used. FR-4 material has the characteristics of good insulation properties, mechanical strength, thermal stability, etc., and is inexpensive. However, FR-4 materials also have some problems, such as large dielectric constant drift and insufficient flame retardant performance.
Metal materials refer to aluminum, copper, tungsten, cobalt and other metal materials,which have good electrical conductivity, can effectively improve the conductivity of PCB boards, and have good cooling performance. The disadvantage of metal materials is that the material cost is high, and it is easy to generate electromagnetic fields, which need to be shielded.
PTFE materials have good chemical resistance, high temperature resistance, dielectric resistance, etc., can be applied to high-speed transmission circuit boards, and PTFE materials can also be applied to microwave circuit boards, but the disadvantage of PTFE materials is that the cost is higher.
Comparison of PCB material properties
Dielectric constant is one of the important indicators affecting the conductivity of PCB board, and the dielectric constant of different PCB materials is different. In general, the smaller the dielectric constant, the smaller the attenuation of the electrical signal during transmission, and the faster the transmission speed.
At present, among the common PCB materials on the market, the dielectric constant of FR-4 material is about 4.5-5.5, while the dielectric constant of PTFE material is only 2.1, and the material with the smallest dielectric constant is fluorinated polyurethane material, with a dielectric constant of only 1.8. For high-speed circuit board designs, selecting materials with a smaller dielectric constant can improve transmission speed and transmission distance.
PCB needs to withstand various mechanical stresses during use, so they need to have certain mechanical strength. Mechanical strength mainly includes bending strength, tensile strength, hardness and other indicators. Silicon carbide materials have large hardness, good bending resistance and tensile strength, and are suitable for high temperature and high strength environments.
The mechanical strength of FR-4 material is also relatively good, but it is easy to deform and crack in high temperature and high humidity environment, so it needs to be reinforced. PTFE materials have poor mechanical strength and generally need to be compounded with other materials.
PCB boards need to withstand certain thermal stress during use, so thermal stability is also one of the key indicators. Silicon carbide materials and FR-4 materials have high thermal stability, can work stably in high temperature environments, and can withstand multiple repeated hot and cold cycles. PTFE materials also have good high temperature resistance and can work in high temperature environments.
Flame retardant performance
PCB boards need to have certain flame retardant properties during use to prevent safety accidents such as fire on the circuit board. The flame retardant performance of silicon carbide material is relatively good, with high heat resistance and fire resistance. The flame retardant performance of FR-4 material is also good, but the flame retardant performance will decrease in some special high temperature and high humidity environment and need to be treated. PTFE materials have poor flame retardant properties and require fire treatment.
Based on the above analysis, silicon carbide materials are suitable for circuit board design in high temperature and high-intensity environments, FR-4 materials are suitable for general circuit board design, and PTFE materials are suitable for high-speed transmission and microwave circuit board design. Choosing the right PCB material can effectively improve the conductivity, mechanical strength, thermal stability and flame retardant performance of the circuit board, improve the quality and stability of the circuit board, and be suitable for different electronic device applications.