FR406N is a high-performance, low-loss FR-4 epoxy laminate and prepreg system designed for applications requiring superior thermal reliability, electrical performance, and mechanical stability. It is widely used in multilayer PCB designs, especially for high-speed digital circuits, RF/microwave systems, and aerospace electronics.

Key Features

1. Material Composition

• Laminate: Epoxy resin reinforced with high-quality woven fiberglass for structural stability and low signal loss.
• Prepreg: Resin-coated fiberglass designed to provide reliable bonding in multilayer PCB stack-ups.

2. Thermal Properties

• Glass Transition Temperature (Tg): 180°C, ensuring stability under thermal stress.
• Decomposition Temperature (Td): Typically around 340°C, suitable for lead-free soldering processes.
• Low Coefficient of Thermal Expansion (CTE): Provides excellent dimensional stability, particularly in the z-axis, reducing the risk of via failures.

3. Electrical Properties

• Dielectric Constant (Dk): Low and stable, typically 4.2 @ 1 GHz, ensuring signal integrity across a wide frequency range.
• Dissipation Factor (Df): Low, around 0.016 @ 1 GHz, minimizing signal loss in high-speed applications.
• High Insulation Resistance: Maintains electrical isolation in dense circuit designs.

4. Mechanical Properties

• Dimensional Stability: Exceptional resistance to mechanical deformation during fabrication.
• Peel Strength: Strong copper-to-laminate adhesion, even after thermal cycling.

Applications

1. High-Speed Digital Circuits

• Ideal for data servers, telecommunication systems, and networking equipment requiring low signal loss.

2. RF and Microwave Circuits

• Suitable for low-frequency RF designs, antennas, and microwave modules.

3. Multilayer PCBs

• Well-suited for high-layer-count designs with dense interconnections.

4. Aerospace and Defense Electronics

• Performs reliably under extreme thermal and environmental stress.

5. Industrial and Automotive Electronics

• Used in control systems, power electronics, and motor drivers.

Technical Specifications

Property	Typical Value
Glass Transition Temperature (Tg)	180°C
Decomposition Temperature (Td)	~340°C
Dielectric Constant (Dk)	4.2 @ 1 GHz
Dissipation Factor (Df)	0.016 @ 1 GHz
Coefficient of Thermal Expansion (CTE)	X/Y: ~14–16 ppm/°C, Z: < 60 ppm/°C
Thermal Conductivity	~0.4 W/m·K
Peel Strength	> 8 lb/in
Flammability Rating	UL 94 V-0
Moisture Absorption	< 0.2%

Fabrication Guidelines

1. Storage and Handling

• Store in a dry, controlled environment to prevent moisture absorption.
• Handle with care to avoid contamination or mechanical damage.

2. Drilling and Hole Preparation

• Use optimized feed rates and spindle speeds for clean and precise drilling.
• Apply desmear and plasma cleaning processes to ensure high-quality hole-wall plating.

3. Lamination Process

• Follow the manufacturer-recommended press cycle with proper temperature and pressure to ensure uniform bonding.

4. Soldering and Assembly

• Fully compatible with lead-free soldering profiles due to its high Tg.
• Use appropriate reflow profiles to avoid thermal stress during assembly.

Advantages

• Thermal Reliability: High Tg and Td allow for operation in challenging thermal environments.
• Electrical Performance: Low Dk and Df ensure excellent signal integrity, even at high frequencies.
• Mechanical Strength: Withstands mechanical stress and maintains dimensional stability.
• Versatility: Applicable across industries such as telecommunications, aerospace, and automotive.

The FR406N laminate and prepreg system is a reliable choice for advanced multilayer PCB applications, offering a balance of thermal stability, electrical performance, and mechanical strength. Its versatility makes it a preferred material for industries that demand high reliability and low signal loss, particularly in high-speed and high-frequency designs.

For detailed process parameters and technical support, consult the manufacturer’s datasheet or application guidelines.