FR-4 glass fiber epoxy laminate for PCB applications

FR-4 Glass Fiber Board Overview

FR-4 glass fiber board is a high-performance printed circuit board (PCB) substrate made from glass fiber cloth as the reinforcing material and epoxy resin as the matrix, with copper foil laminated on the surface. The “FR” in FR-4 stands for “Flame Retardant”, and “4” is the material grade code. Its main features include excellent mechanical strength, dimensional stability, electrical insulation properties, and flame retardancy. FR-4 is widely used in the manufacturing of circuit boards for various electronic products and is one of the most commonly used and mainstream PCB substrates today.

Main Structure

1. Glass Fiber Base: Uses high-strength glass fiber cloth to ensure excellent mechanical strength and dimensional stability.
2. Epoxy Resin: The glass fiber cloth is impregnated with high-performance epoxy resin to enhance the board’s heat resistance, insulation, and overall stability.
3. Copper Foil: The surface is covered with high-purity electrolytic copper foil, making it easy to etch and form fine circuit patterns.

Main Features of FR-4 Circuit Boards

• Excellent dimensional stability, low coefficient of thermal expansion, and not easily deformed.
• Superior dielectric properties, suitable for high-frequency and high-speed signal transmission.
• Outstanding heat resistance, suitable for high-temperature processes such as reflow soldering, and supports long-term operation at high temperatures.
• High mechanical strength, impact and flex resistance, suitable for multilayer and high-density PCB manufacturing.
• Minimal resin smear during high-speed drilling, resulting in smooth hole walls and good processability.
• Strong flame retardancy, remaining safe and reliable even at high temperatures.
• Good moisture and chemical resistance, with a long service life.
• Core colors are mainly yellow or white, which is convenient for product identification and quality management.
• Compatible with various surface treatment processes, such as HASL (Hot Air Solder Leveling), ENIG (Electroless Nickel Immersion Gold), and OSP (Organic Solderability Preservative), meeting different assembly requirements.

Main Applications of FR-4 Printed Circuit Boards

• Widely used in the manufacturing of circuit boards for mobile phones, computers, testing equipment, video recorders, household appliances, and other consumer electronic products.
• Applied in high-reliability and high-performance fields such as military equipment, guidance systems, automotive electronics, aerospace, medical instruments, and industrial control.
• The preferred substrate for multilayer, high-density, and high-frequency/high-speed printed circuit boards, suitable for communication, networking, servers, and other electronic devices.
• Suitable for electronic products that require heat resistance, moisture resistance, flame retardancy, and long service life.

Common Specifications

• Base thickness: 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm.
• Copper thickness: 18μm, 35μm, 70μm.
• Board size: 1044 x 1245mm.
• Core color: yellow, white.
• Surface finishes: HASL, ENIG, OSP.