2. PCB Construction

Specification Item	Technical Details & Standard
Base Material	ISOLA 370HR High Tg 180°C FR4 Laminate & Prepreg
Layer Count	6-Layer High-Reliability Rigid PCB
Finished Board Thickness	1.6mm
Board Dimension & Quantity	111mm × 78mm, 1 PCS
Full Layer Copper Weight	1oz (35μm) Finished Copper per Layer
Hole Copper Thickness	25μm (IPC-Class-3 High Reliability Standard)
Precision Impedance Design	Top Trace Width: 11mil, Custom 50Ohm Impedance Control
Surface Finish	2μ” ENIG (Electroless Nickel Immersion Gold)
Solder Mask	Green Solder Mask
Silkscreen	White Legend
Fabrication Standard	IPC-Class-3 High-Reliability Specification
Artwork Format	Gerber RS-274-X

3. Professional PCB Stackup Structure

This 6-layer rigid PCB adopts a standardized symmetrical stackup structure built entirely with ISOLA 370HR high-performance FR4 dielectric materials. The uniform high-Tg material configuration delivers ultra-stable thermal performance, low thermal expansion and excellent structural consistency, fully meeting the strict requirements of multilayer sequential lamination and high-speed impedance control circuits.

4. Core Manufacturing & Process Advantages

1. High-Precision Impedance Stability: Custom 11mil top trace width and professional 50Ohm impedance calibration eliminate signal attenuation and phase deviation, ensuring stable high-speed signal transmission.
2. IPC-Class-3 Ultra-High Reliability: 25μm thick hole copper enhances hole wall adhesion and thermal shock resistance, avoiding delamination and barrel cracking in long-term high-temperature operation.
3. Superior Thermal Structural Stability: Built with ISOLA 370HR 180°C high-Tg material, effectively resisting thermal deformation and size drift during multiple lamination and reflow processes.
4. High-Quality Surface Finish: 2μ” ENIG plating provides uniform surface flatness, excellent corrosion resistance and repeatable SMT assembly performance.
5. Standardized Protective Coating: Green solder mask and white silkscreen achieve comprehensive circuit insulation protection and clear component marking.

5. ISOLA 370HR Material  Introduction

ISOLA 370HR is a premium high-performance FR-4 dielectric system engineered for high-reliability multilayer printed circuit board applications requiring extreme thermal stability and structural durability. This industrial-grade FR4 material is synthesized with exclusive multifunctional high-performance epoxy resin and reinforced with high-quality E-grade fiberglass fabric, achieving comprehensive upgrades in thermal resistance, dimensional stability and environmental adaptability compared with conventional standard FR4 substrates.

Retaining full compatibility with traditional FR4 manufacturing processes, the 370HR system features significantly lower thermal expansion coefficients and superior high-temperature endurance. Its mechanical strength, chemical corrosion resistance and moisture resistance all surpass ordinary FR4 materials, delivering more stable batch production performance. ISOLA 370HR laminate PCB supports laser fluorescence and UV blocking characteristics, perfectly matching automated optical inspection (AOI), optical positioning systems and photo-imageable solder mask processes to greatly improve PCB fabrication and assembly efficiency and accuracy.

Widely recognized as a top-tier material for sequential lamination multilayer designs, ISOLA 370HR high-frequency material boasts ultra-reliable layered bonding performance and thermal cycling stability. Fully RoHS compliant, this eco-friendly high-Tg FR4 material has obtained complete industry certifications, making it a mainstream high-reliability substrate for industrial, automotive, communication and military electronic equipment.

6. Key Performance Features of ISOLA 370HR Material

1. Class-Leading Thermal Performance: Features 180°C Tg (DSC) and 340°C Td (5% weight loss via TGA), with T260 thermal resistance up to 60 minutes and T288 up to 30 minutes, adapting to extreme high-temperature processing and working environments.
2. Low Thermal Expansion & High Stability: Optimized low CTE design effectively reduces dimensional deformation and layer separation risks for long-term reliable operation.
3. UV Blocking & AOI Fluorescence Compatibility: Supports high-precision automated optical inspection and solder mask imaging, improving production throughput and inspection accuracy.
4. Excellent CAF Resistance: Effectively prevents conductive anodic filament growth, avoiding circuit short-circuit and failure caused by electrochemical migration.
5. Mature FR4 Process Compatibility: Fully consistent with conventional FR4 processing flows, no special equipment required, balancing high performance and processing economy.
6. Diversified Material & Copper Specifications: Supports multiple core thicknesses, prepreg forms, HTE/RTF copper foil and various copper weight options for flexible customized design.
7. Complete Industry Qualifications: Compliant with IPC-4101D standards and UL E41625 certification, qualified for UL MCIL program, meeting global industrial safety requirements.
8. Eco-Friendly Compliance: Strictly RoHS compliant, suitable for commercial, industrial and military high-standard electronic products.
10. 7.ISOLA 370HR Datasheet

Property	Typical Value	Specification	Units	Test Method
Glass Transition Temperature (Tg) by DSC	180	170	ºC	IPC-TM-650 2.4.25
Decomposition Temperature (Td) by TGA @ 5% weight loss	340	–	ºC	ASTM D3850
T260 Thermal Stability	60	–	Minutes	ASTM D3850
T288 Thermal Stability	30	–	Minutes	ASTM D3850
CTE, Z-axisA. Pre-TgB. Post-Tg	45230	–	ppm/ºC	IPC-TM-650 2.4.24
CTE, X-, Y-axesA. Pre-TgB. Post-Tg	13/1414/17	–	ppm/ºC	IPC-TM-650 2.4.24
Z-axis Expansion (50-260ºC)	2.8	–	%	IPC-TM-650 2.4.24
Thermal Conductivity	0.4	–	W/mK	ASTM D5930
Thermal Stress 10 sec @ 288ºCA. UnetchedB. Etched	PassPass Visual	–	Rating	IPC-TM-650 2.4.13.1
Dielectric Constant (Dk)(Laminate & prepreg, 50% resin)A. @ 100 MHz (HP4285A)B. @ 1 GHz (HP4291A)C. @ 2 GHz (Bereskin Stripline)D. @ 5 GHz (Bereskin Stripline)E. @ 10 GHz (Bereskin Stripline)	4.244.174.043.923.92	5.4––––	–	IPC-TM-650 2.5.5.3IPC-TM-650 2.5.5.9IPC-TM-650 2.5.5.5IPC-TM-650 2.5.5.5IPC-TM-650 2.5.5.5
Loss Tangent (Df)(Laminate & prepreg, 50% resin)A. @ 100 MHz (HP4285A)B. @ 1 GHz (HP4291A)C. @ 2 GHz (Bereskin Stripline)D. @ 5 GHz (Bereskin Stripline)E. @ 10 GHz (Bereskin Stripline)	0.01500.01610.02100.02500.0250	0.035––––	–	IPC-TM-650 2.5.5.3IPC-TM-650 2.5.5.9IPC-TM-650 2.5.5.5IPC-TM-650 2.5.5.5IPC-TM-650 2.5.5.5
Volume ResistivityA. 96/35/90B. After moisture resistanceC. At elevated temperature	–3.0×10⁸7.0×10⁸	1.0×10⁶–1.0×10³	MΩ·cm	IPC-TM-650 2.5.17.1
Surface ResistivityA. 96/35/90B. After moisture resistanceC. At elevated temperature	–3.0×10⁶2.0×10⁸	1.0×10⁴–1.0×10³	MΩ	IPC-TM-650 2.5.17.1
Dielectric Breakdown	>50	–	kV	IPC-TM-650 2.5.6
Arc Resistance	115	60	Seconds	IPC-TM-650 2.5.1
Electric Strength (Laminate & prepreg)	54 (1350)	30 (750)	kV/mm (V/mil)	IPC-TM-650 2.5.6.2
Comparative Tracking Index (CTI)	3 (175-249)	–	Class (Volts)	UL-746A / ASTM D3638
Peel StrengthA. Low profile / Very low profile copper (>17 microns)B. Standard profile copper1. After thermal stress2. At 125ºC3. After process solutions	1.14 (6.5)1.25 (7.0)1.25 (7.0)1.14 (6.5)	0.70 (4.0)0.80 (4.5)0.70 (4.0)0.55 (3.0)	N/mm (lb/inch)	IPC-TM-650 2.4.8IPC-TM-650 2.4.8.2IPC-TM-650 2.4.8.3
Flexural StrengthA. Lengthwise directionB. Crosswise direction	9000077000	–	lb/inch²	IPC-TM-650 2.4.4
Tensile StrengthA. Lengthwise directionB. Crosswise direction	5590035620	–	lb/inch²	–
Young's ModulusA. Grain directionB. Fill direction	37443178	–	ksi	–
Poisson's RatioA. Grain directionB. Fill direction	0.1770.171	–	–	–
Moisture Absorption	0.15	–	%	IPC-TM-650 2.6.2.1
Flammability (Laminate & prepreg)	V-0	–	Rating	UL 94
Max Operating Temperature	130	UL Cert	ºC	–

8. Typical Application

With ultra-high thermal stability, precise impedance controllability, CAF resistance and AOI compatibility, ISOLA 370HR 6-layer multilayer PCBs are widely applied in high-reliability and high-speed electronic fields:

1. High-speed digital communication equipment and signal processing systems
2. Industrial control, automation and precision testing devices
3. Automotive electronics, vehicle-mounted control modules
4. Aerospace and military-grade high-reliability electronic systems
5. Sequential lamination multilayer high-density PCB projects
6. Precision impedance control circuit boards and high-frequency signal modules
7. Medical equipment, instrumentation and high-end consumer electronics

9. Product Overall Summary

ISOLA 370HR 6-Layer 1.6mm ENIG PCB is a high-reliability multilayer rigid circuit board built with authentic ISOLA 370HR 180°C high-Tg FR4 material. Featuring full-layer 1oz copper, 2μ” ENIG surface finish, dual-side green solder mask and white silkscreen, this PCB adopts IPC-Class-3 25μm hole copper standard and precise 11mil trace 50Ohm impedance control design. Benefiting from 370HR material’s low CTE, superior thermal resistance, CAF resistance and AOI compatibility, it delivers stable dimensional accuracy and consistent electrical performance in high-temperature and long-term operating environments. Ideal for high-speed communication, industrial control, automotive and aerospace electronic systems, 370HR customized 6-layer PCB provides reliable, high-precision and cost-effective circuit solutions for high-reliability industrial applications.

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