1. Core characteristics of FR4 copper clad laminate (why is it widely used in PCB?)
The key to why FR4 copper clad laminate has become the mainstream substrate of PCB is its comprehensive performance balance, which perfectly meets the conventional needs of most electronic devices:
Low cost: The raw materials (glass fiber, epoxy resin) are widely available, the production process is mature, and the price is much lower than special materials such as high-frequency boards (such as PTFE) and ceramic substrates, which are suitable for cost-sensitive scenarios such as large-scale consumer electronics.
High mechanical strength: The addition of glass fiber cloth significantly improves the rigidity, tensile strength, and dimensional stability of the board, and can withstand mechanical processing such as drilling and stamping in PCB manufacturing, as well as vibration and impact in subsequent assembly.
Moderate electrical performance: The dielectric constant (Dk≈4.5-5.0) and dielectric loss (Df≈0.01-0.015) are low, which can meet the signal transmission requirements of most low-frequency/medium-frequency electronic devices (such as home appliances and computers). Good temperature resistance: long-term working temperature can reach 130℃, short-term temperature resistance is above 180℃, and it can cope with the heat generated by normal operation of electronic equipment (such as chips, power modules).
Excellent processing performance: easy to cut and drill, strong bonding with copper foil, suitable for PCB pattern transfer, etching, drilling and other processes.
2. Specific application scenarios of FR4 copper clad laminate in PCB
FR4 copper clad laminate is the "standard" substrate of conventional PCB and is widely used in electronic devices with high requirements for cost, dimensional stability and mechanical strength.
1. Consumer electronics
Mobile phones/tablets: motherboards, camera module boards, battery management boards, etc. The low cost and high rigidity of FR4 can meet the needs of thin and light mobile phones and mass production.
Laptops/desktops: motherboards, graphics cards, memory slot boards, etc. The high mechanical strength of FR4 can support the installation of large chips (such as CPU, GPU) and dense components.
Home appliances: air conditioning control boards, washing machine motherboards, TV power boards, etc. Home appliances are sensitive to cost, and FR4 has significant cost-effectiveness.
2. Industrial control and automation
PLC (Programmable Logic Controller): control boards, interface boards, etc. The industrial environment has high requirements for the durability (anti-vibration, temperature resistance) of PCBs, and the mechanical strength and temperature resistance of FR4 can meet the requirements.
Sensor Module: Mounting board for common industrial sensors. The dimensional stability of FR4 ensures the accuracy of sensor signals.
3. Automotive electronics (non-extreme scenarios)
Body control module (BCM): circuit boards for door, window, and lighting control. FR4 can meet the reliability requirements of the car under normal temperature.
In-car entertainment system: central control screen driver board, audio control board, etc. FR4 is the first choice for high cost and processing performance requirements.
4. Communication equipment (medium and low frequency scenarios)
Router/switch: main board, interface board (non-5G high frequency part). FR4's low cost and high processing performance are suitable for circuit boards that process medium and low speed signals.
Base station power module: substrate for power conversion and filtering circuits. FR4's insulation and voltage resistance (usually ≥3kV) can ensure the safety of the power module.
AHD FR4 copper clad laminate stock
3. The key role of FR4 copper clad laminate in PCB manufacturing
1. As a circuit carrier
The copper foil on the surface of FR4 forms the target circuit line after pattern transfer (photolithography) and etching, which is the basis for component pin connection and signal transmission.
2. Support interlayer connection
In multilayer PCB, the insulating layer of FR4 fills the gap of glass fiber cloth, and interlayer conduction is achieved through electroplating after drilling. The rigidity of FR4 ensures the stability of the multilayer structure.
3. Influence on processing technology
Drilling: The hardness of glass fiber cloth will affect the wear of the drill bit (high hardness drill needle should be selected).
Surface treatment: The copper foil on the surface of FR4 needs to be browned/blackened (to enhance the bonding strength with the substrate) to meet the requirements of subsequent copper plating, tin plating and other processes.
Molding: The high rigidity of FR4 facilitates cutting (V-cut or milling) to ensure the dimensional accuracy of the finished PCB.
FR4 copper clad laminate suitable for CNC machining
FR4 copper clad laminate has become the "core substrate" of most conventional PCBs due to its low cost, high mechanical strength and good processing performance, supporting the operation of electronic devices in the fields of consumer electronics, industrial control, automotive electronics, etc. As electronic devices develop towards high performance, the application scenarios of FR4 are limited by special requirements such as high frequency and heat dissipation, but its dominant position in traditional fields will still be a common material in the short term.
