4-Layer 8mil RO4003C + RO4450F Rogers High Frequency PCB with Immersion Gold 2 u"

4-Layer 8mil RO4003C + RO4450F Rogers High Frequency PCB with Immersion Gold 2 u"

1. Product Overview

This 4-layer high-frequency board is engineered on a symmetric Rogers material stackup combining two 0.203 mm (8 mil) RO4003C hydrocarbon-ceramic cores with RO4450F bondply as the interlayer dielectric. Built to a finished board thickness of 0.75 mm with 1 oz finished copper on all four layers, the board delivers stable controlled-impedance performance and low insertion loss for RF and microwave circuits. The construction employs full resin-plugged and electroplated-filled vias, 25μm via plating, and immersion gold (2μ") surface finish, all manufactured to IPC-6012 Class 3 standards.

With dimensions of 98 mm×62 mm per piece and 100% electrical testing prior to shipment, this RO4003C multilayer PCB is suited for high-reliability communications, test and measurement, and RF front-end applications where signal integrity and thermal stability are critical.

2. PCB Construction Details

The table below summarizes the complete construction specifications of this 4-layer Rogers PCB, covering material composition, dimensional tolerances, copper weight, surface finish, via processing, and quality certification standards.

3. PCB Stackup

The board adopts a symmetric double-core stackup with two RO4003C dielectric cores separated by a RO4450F bonding prepreg, ensuring balanced thermal expansion, minimal warpage, and consistent impedance control across all signal layers.

4. Key Performance and Differentiators

4.1 Low-Loss Dielectric Performance

The RO4003C core exhibits a dissipation factor of 0.0027 at 10 GHz and a tightly controlled dielectric constant of 3.38±0.05, minimizing signal attenuation in high-frequency transmission lines. The thermal coefficient of Dk is only +40 ppm/°C across−50°C to +150°C, ensuring impedance stability over wide operating temperature ranges. Unlike PTFE-based microwave laminates,RogersRO4003Cprocesses through standard FR-4 fabrication lines, reducing manufacturing cost and lead time without sacrificing RF performance.

4.2 Resin-Plugged and Electroplated Vias

Every via on this board undergoes resin plugging followed by electroplated copper filling. This process eliminates air gaps within via barrels, prevents solder wicking during SMT assembly, improves vertical thermal conduction, and creates a coplanar surface suitable for fine-pitch component mounting—a significant reliability upgrade over conventional tent or capped vias.

4.3 IPC-6012 Class 3 Compliance

Manufactured to the highest rigid PCB performance class, the board meets stringent requirements for via plating thickness (25μm minimum), hole wall quality, dimensional accuracy, and dielectric integrity. Class 3 certification ensures suitability for high-reliability, mission-critical electronic assemblies where failure is not an option.

4.4 Immersion Gold 2μ" Finish

A 2 micro-inch immersion gold finish provides a flat, oxidation-resistant, and highly solderable surface ideal for fine-pitch RF connectors, QFN packages, and wire-bondable pads. The finish maintains consistent contact resistance and supports multiple lead-free reflow cycles without surface degradation.

4.5 Symmetric Stackup for Thermal Stability

With matched RO4003C cores on both outer layers and a low-CTE RO4450F bondply (Z-axis CTE of 50 ppm/°C), the stackup minimizes warpage and plated-through-hole fatigue under thermal cycling. The RO4003C core itself has a Z-axis CTE of just 46 ppm/°C, closely matching copper and extending PTH reliability in temperature-stressed environments.

5. Typical Applications

This 4-layer RO4003C + RO4450F PCB is well suited for:

• RF power amplifiers and low-noise amplifiers
• Microwave backhaul radio modules
• Small cell and DAS (Distributed Antenna System) front-ends
• Test and measurement instrumentation
• Radar and satellite communication subsystems
• Automotive radar sensors
• High-speed controlled-impedance interconnects requiring stable Dk over temperature.

6. Conclusion

In summary, this 4-layer Rogers RO4003C ENIG PCB combines the low-loss electrical performance of RO4003C cores with the reliable multilayer bonding capability of RO4450F prepreg in a compact 0.75 mm format. The IPC-6012 Class 3 manufacturing standard, resin-filled vias, and immersion gold finish collectively ensure high signal integrity, assembly reliability, and long-term thermal stability. For designers seeking a cost-effective, FR-4-processable high-frequency PCB solution without compromising on RF performance or build quality, this construction offers a proven and differentiated option.

CCL Material Knowledge: Rogers RO4003C and RO4450F

7.1 RO4003C High-Frequency Core Laminate

Figure 2: Rogers RO4003C High-Frequency Copper-Clad Laminate (CCL)

RO4003C is a proprietary woven-glass-reinforced hydrocarbon/ceramic laminate that combines the electrical performance of PTFE/woven-glass materials with the manufacturability of standard epoxy/glass (FR-4). It utilizes both 1080 and 1674 glass fabric styles, with all configurations meeting the same electrical performance specification. The material is non-brominated and is not UL 94 V-0 rated; for designs requiring V-0 flame retardancy, Rogers RO4350B or RO4835 are recommended alternatives.

A defining advantage of RO4003C is its low Z-axis coefficient of thermal expansion of 46 ppm/°C, which closely matches copper's CTE and enhances plated-through-hole reliability in multilayer constructions. Its thermal conductivity of 0.71 W/m·K at 50°C provides improved heat dissipation compared to standard FR-4 (typically 0.3 W/m·K), benefiting power amplifier and high-current designs. The glass transition temperature exceeds 280°C, ensuring dimensional stability through multiple lead-free reflow cycles. RO4003C is available in thicknesses ranging from 0.203 mm to 1.524 mm, offering designers flexibility across single-sided and multilayer applications.

The following table presents the complete typical electrical, thermal, and mechanical properties of RO4003C laminate per Rogers Corporation official datasheet.

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7.2 RO4450F High-Frequency Bondply

Figure 3: Rogers RO4450F Prepreg / Bondply Material

RO4450F is a thermoset prepreg bondply based on theRO4000 series core material formulation, specifically designed for bonding multilayer high-frequency PCB constructions. It is fully compatible with RO4003C, RO4350B, RO4835, and otherRO4000 series laminates, and can also be combined with low-flow FR-4 bondply in non-homogeneous multilayer stacks using a single bond cycle.

RO4450F demonstrates improved lateral resin flow capability, making it the preferred choice for designs with difficult fill requirements such as high-copper-coverage inner layers or resin-plugged via constructions. With a high post-cure Tg exceeding 280°C, fully cured RO4450F can withstand sequential lamination cycles, enabling complex multilayer builds. The material is CAF (Conductive Anodic Filament) resistant, UL 94 V-0 rated, and compatible with lead-free solder processing. The standard cured thickness is 0.0040" (0.102 mm)±0.0006", available in panel sizes up to 24"×36" (610×915 mm). Its decomposition temperature (Td) of 390°C ensures robust thermal performance during assembly and operation.

The following table presents the complete typical properties of RO4450F bondply per Rogers Corporation official datasheet.

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7.3 Processing Considerations

1) Drilling Parameters

RO4003C and RO4450F can be drilled using standard carbide drill bits with typical parameters:

• Surface speed: 300-500 SFM (90-150 m/min)
• Chip load: 0.002-0.004 in/rev (0.05-0.10 mm/rev)
• Tool life: 2,000-3,000 hits (based on hole wall quality inspection)
• Minimal desmear required due to high Tg (>280°C)

2) Routing Parameters

Routing these materials requires carbide tools with the following conditions:

• Surface speed: <500 SFM
• Chip load: 0.001-0.0015 in/rev
• Maximum stack height based on 70% of flute length

3) Bonding Considerations

RO4450F bondply provides superior adhesion between RO4003C cores with recommended lamination temperatures of 180-200°C and pressures of 300-400 psi. Vacuum lamination is recommended to minimize void formation.

7.4 Conclusion

The RO4003C and RO4450F material pair represents a well-validated, cost-effective solution for high-frequency multilayer PCB designs. RO4003C delivers tightly controlled Dk (3.38±0.05) and ultra-low loss (0.0027 @10 GHz) with FR-4-compatible processing, while RO4450F provides reliable interlayer bonding with matched electrical properties (Dk 3.52), CAF resistance, and excellent thermal-mechanical stability. Together, they enable designers to achieve microwave-grade performance in a manufacturable, high-yield PCB construction suitable for volume production.