370HR is a high-performance FR-4 epoxy laminate and prepreg system known for its exceptional thermal reliability, mechanical strength, and electrical performance. With a high glass transition temperature (Tg) of 180°C, it is designed for applications requiring excellent performance under thermal and mechanical stress, making it suitable for multilayer PCBs, high-speed digital designs, and aerospace and defense electronics.

Key Features

1. Material Composition

• Laminate: Epoxy resin reinforced with woven fiberglass for structural integrity.
• Prepreg: A resin-coated fiberglass material used for layer bonding in multilayer PCBs.

2. Thermal Properties

• Glass Transition Temperature (Tg): 180°C, ensuring stability under high thermal loads.
• Decomposition Temperature (Td): Typically around 350°C, enabling reliability during soldering and thermal cycling.
• Low Coefficient of Thermal Expansion (CTE): Maintains stability, especially in the z-axis, reducing risk of delamination or via failure.

3. Electrical Properties

• Dielectric Constant (Dk): Typically 4.2 at 1 GHz, offering stability across a range of frequencies.
• Dissipation Factor (Df): Low value, around 0.016, ensuring minimal signal loss.
• High Insulation Resistance: Ensures consistent electrical isolation in multilayer designs.

4. Mechanical Properties

• Dimensional Stability: Excellent resistance to warping and mechanical deformation.
• Peel Strength: High copper adhesion strength, even after thermal cycling.

Applications

1. Multilayer PCBs

• Perfect for dense interconnect designs and high layer-count PCBs.

2. High-Speed Digital Circuits

• Suitable for telecommunications, networking equipment, and data servers requiring low signal loss.

3. Aerospace and Defense Electronics

• Reliable performance under extreme environmental conditions, including thermal and mechanical stress.

4. Industrial Electronics

• Ideal for motor drivers, control systems, and power electronics.

Technical Specifications

Property	Typical Value
Glass Transition Temperature (Tg)	180°C
Decomposition Temperature (Td)	~350°C
Dielectric Constant (Dk)	4.2 @ 1 GHz
Dissipation Factor (Df)	0.016 @ 1 GHz
Thermal Conductivity	0.4 W/m·K
Coefficient of Thermal Expansion (CTE)	X/Y: ~12 ppm/°C, Z: < 60 ppm/°C
Peel Strength	> 8 lb/in
Flammability Rating	UL 94 V-0

Fabrication Guidelines

1. Storage and Handling

• Store prepregs in a controlled environment to prevent moisture absorption.
• Ensure laminates are free from contaminants before processing.

2. Drilling and Hole Preparation

• Use sharp drill bits and proper spindle speeds to avoid delamination and rough hole walls.
• Perform desmear and plasma cleaning to ensure optimal hole-wall plating adhesion.

3. Lamination Process

• Follow the recommended press cycle, including controlled temperature ramp rates and pressure settings, to ensure proper bonding.

4. Soldering and Assembly

• Compatible with lead-free soldering processes due to its high Tg.
• Use proper heat sinking and reflow profiles to avoid excessive thermal stress.

Advantages

• Thermal Stability: High Tg and Td enable operation under extreme thermal conditions.
• Electrical Reliability: Low Df and stable Dk support high-speed signal integrity.
• Mechanical Strength: Withstands mechanical stress during fabrication and use.
• Versatility: Suitable for a broad range of industries, including telecom, aerospace, and automotive.

The 370HR laminate and prepreg system provides a robust solution for demanding PCB applications requiring high reliability, low electrical loss, and mechanical stability. With its high Tg, excellent thermal and electrical properties, and wide application range, it is a trusted choice for multilayer PCBs, high-speed designs, and ruggedized electronics.

For further details and specific fabrication parameters, consult the manufacturer’s datasheet.