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.
