6-layer Isola 370HR High-Tg FR-4 PCB 2μ" ENIG Impedance Controlled

6-layer Isola 370HR High-Tg FR-4 PCB 2μ" ENIG Impedance Controlled

1. Product Executive Overview

This custom 6-layer rigid multilayer PCB adopts Isola 370HR high-Tg FR-4 copper-clad laminate as core dielectric substrate, with uniform 1oz copper weight on all six conductive layers, finished board thickness fixed at 1.6mm. The unit dimension is 111mm×78mm with dimensional tolerance±0.15mm per single unit. The board implements precise 50Ω single-ended impedance control on the TOP signal layer via fixed 11mil trace width, eliminating blind and buried vias and adopting full through-hole via design compliant with IPC-3 hole copper plating specification (25μm hole wall copper thickness). The surface finish is 2μ”immersion gold (ENIG) following IPC-4552 standard, matched with standard green solder mask on both top and bottom sides and white ink silkscreen printing on double sides for clear component marking. All finished boards undergo 100% electrical continuity testing before delivery to eliminate open/short circuit defects.

Targeted for high-temperature, high-speed signal transmission scenarios including industrial control mainboards, automotive communication modules, medium-frequency signal acquisition equipment and high-reliability consumer networking hardware, this PCB differentiates itself from conventional standard FR-4 multi-layers through the thermal stability and low dielectric loss advantages of ISOLA 370HR substrate. Its symmetrical 6-layer PCB stackup optimizes signal shielding and power integrity, while standardized ENIG surface finish balances solderability, contact durability and cost efficiency for mid-to-high reliability electronic assemblies.

2. PCB Core Construction Details

This table systematically summarizes all mechanical, electrical, surface treatment and testing specifications of the finished PCB, covering substrate, layer structure, copper, dimension, impedance, surface coating, silkscreen and factory inspection standards.

3. 6-Layer PCB Standard Stackup Layout

This table presents the balanced symmetrical layer sequence matching the 1.6mm finished thickness and 1oz full-layer copper design, optimized for 50ΩTOP layer impedance control and EMI suppression with complete ground and power reference planes.

4. Key Differentiated Technical Advantages of This PCB

4.1 Thermal Reliability Superiority via ISOLA 370HR Substrate

Unlike conventional Tg 130–150°C general FR-4 materials, ISOLA 370HR features a DSC-tested glass transition temperature of 180°C and thermal decomposition temperature Td 340°C (5% weight loss via TGA). It maintains structural integrity for 60 minutes at T260 and 30 minutes at T288, fully adapting to multiple lead-free reflow cycles without delamination, resin cracking or copper peeling. This core advantage reduces PCB failure risks for devices operating under continuous high-temperature load such as industrial power modules and automotive on-board electronics.

4.2 Precision 50ΩImpedance Control for Signal Integrity

The TOP layer specifies fixed 11mil trace width matched with ISOLA 370HR’s stable Dk=4.04 @2GHz dielectric constant, delivering tight±10% impedance tolerance without frequent stackup adjustment. Consistent dielectric constant across temperature ranges minimizes signal reflection, crosstalk and attenuation for medium-frequency communication signals, outperforming standard FR-4 with variable Df loss tangent at high frequencies.

4.3 Standardized IPC-3 Hole Copper & 2μ”ENIG Surface Finish

25μm hole wall copper plating complies with IPC Class 3 high-reliability hole requirements, ensuring robust interlayer electrical conduction and resisting thermal cycling fatigue. The 2μ”immersion gold meets IPC-4552 Class 1 ENIG specifications, offering flat, coplanar pad surfaces for SMT soldering, moderate oxidation resistance and lower manufacturing cost than thicker 3μ”gold finishes for non-frequent plug-in contact applications. Double-sided green solder mask and white silkscreen balance protection, insulation and visual identification efficiency.

4.4 Full Quality Assurance Mechanism

100% electrical testing before shipment screens all open-circuit, short-circuit and high-impedance connection defects, paired with AOI visual inspection for trace, solder mask and silkscreen defects. Dimensional control±0.15mm ensures perfect assembly matching with customer mechanical housings and connectors.

5. PCB Product Conclusion

This 6-layer ISOLA 370HR ENIG controlled-impedance PCB forms a balanced high-reliability multilayer circuit solution that integrates advanced high-Tg substrate, standardized impedance design, IPC-compliant plating and complete pre-delivery testing workflows. Its core competitive strength lies in the combination of ISOLA 370HR’s industry-leading thermal and dielectric performance and a cost-effective all-through-hole 6-layer stackup without complex blind/buried vias. The product fills the market gap between low-cost standard FR-4 multi-layers and ultra-high-performance polyimide high-frequency boards, serving as a cost-efficient choice for mid-temperature, medium-speed signal electronic equipment. All design parameters are fully quantifiable and traceable to IPC international standards, supporting mass production repeatability and long-term product reliability for industrial, automotive and communication electronics customers.

Supplementary Introduction to ISOLA 370HR CCL Copper-Clad Laminate

1. CCL Material Brief Summary

ISOLA 370HR is a premium high-Tg FR-4 copper-clad laminate and prepreg series developed by Isola Group, formulated with proprietary multifunctional high-temperature epoxy resin reinforced with E-grade electronic glass fabric. Designed for multilayer PCB applications requiring extreme thermal endurance and CAF resistance, it holds IPC-4101D and UL certification (File No. E41625) and maintains processing compatibility with traditional FR-4 production lines without special equipment modification. The following content extracts full technical data from official datasheets and systematically explains material features, electrical, thermal and mechanical performance.

2. Full Datasheet Key Property Table of ISOLA 370HR

3. Core Material Characteristic Analysis

3.1 Outstanding Thermal Stability for Lead-Free Assembly

• The 180°C Tg and 340°C Td values are the core distinguishing feature from ordinary FR-4 (Tg 130–150°C). During multiple lead-free reflow peaks at 260°C–288°C, the resin matrix resists rapid thermal decomposition, avoiding interlayer delamination, bubble generation and copper foil separation. The long T260/T288 delamination time enables PCBs to withstand prolonged high-temperature exposure during rework and wave soldering, drastically reducing scrap rate in high-volume SMT production. Low Z-axis CTE minimizes dimensional expansion mismatch between copper foil and dielectric substrate, lowering thermal stress and trace cracking risks.

3.2 Superior Electrical & High-Signal Performance

• Stable Dk=4.04 and low Df=0.0210 at 2GHz deliver consistent signal transmission performance across medium-to-high frequency bands, making it ideal for 50Ωcontrolled impedance routing designs as specified in the target PCB. The material’s UV-blocking and laser fluorescence properties optimize AOI automatic optical inspection accuracy, reducing false detection during PCB manufacturing quality control. In addition, the resin system provides premium CAF (Conductive Anodic Filament) resistance, preventing conductive ion migration between vias under high humidity and voltage bias, critical for long-lifespan industrial and automotive electronics.

3.3 Compatibility with Standard PCB Fabrication Processes

• Unlike specialized high-frequency substrates requiring modified lamination and drilling parameters, ISOLA 370HR retains identical processing windows as conventional FR-4. Manufacturers can use standard prepreg lamination pressure, drill bits and etch chemicals without equipment upgrades, balancing advanced performance with production cost control. Available copper foil weights include 0.5oz, 1oz and 2oz, perfectly matching the full-layer 1oz copper specification of the 6-layer PCB in this document. Standard core thickness ranges from 0.05mm to 3.2mm, supporting flexible stackup design to achieve target finished board thickness of 1.6mm.

3.4 Compliance & Industrial Application Coverage

• The material fully complies with RoHS environmental directives and holds UL, IPC global industry certifications, suitable for global electronic product export. Main application fields include industrial instrumentation, automotive power and communication modules, enterprise networking equipment, medical monitoring hardware and consumer high-speed communication devices. It is recognized as the mainstream high-reliability FR-4 substrate for sequential multilayer lamination designs in the PCB industry.

4. ISOLA 370HR CCL Material Conclusion

ISOLA 370HR represents a mature balanced high-Tg FR-4 substrate solution that bridges the performance gap between low-cost standard FR-4 and high-price special dielectric materials. Its integrated advantages of extreme thermal stability, low dielectric loss, superior CAF resistance and universal process compatibility make it the optimal substrate choice for the6-layer controlled-impedance ENIG PCB introduced earlier. Every thermal, electrical and mechanical parameter listed in the datasheet table provides solid technical support for the PCB’s 50Ωimpedance control, multi-reflow assembly durability and long-term operational reliability. For electronics designers pursuing elevated thermal and signal performance without excessive production cost inflation, ISOLA 370HR delivers stable, verifiable, industry-proven material performance for multilayer PCB mass production.