Rogers Ro4360 PCB

Description

Basic Parameters
Layer Count: 4-layer PCB
Board Size: 97mm × 97mm
Board Thickness: 2.08mm
Stack-up:
4360 (1.524mm): A high-frequency dielectric layer used as the main substrate, providing low loss and stable dielectric constant for high-frequency signal transmission.
Rogers 4450F (PP): A high-performance bonding material that ensures stability between layers.
3006 (0.254mm): A dielectric layer offering low loss and precise impedance control, suitable for high-frequency applications.
Copper Thickness: 1oz (35µm), ensuring proper current-carrying capacity and low signal loss for high-frequency transmission.
Process Requirements
Surface Finish: ENIG (Electroless Nickel Immersion Gold)
ENIG provides excellent surface flatness, oxidation resistance, and reliability of solder joints, ensuring high signal quality for high-frequency applications.
Blind Hole Design: Drl3-4
Blind holes are designed to connect Layer 3 and Layer 4, reducing via parasitics and improving signal integrity.
Special Requirements:
No Solder Mask: Eliminating solder mask reduces high-frequency signal loss and prevents signal coupling in the mask layer.
No Silkscreen: Removing silkscreen avoids potential interference with electrical performance in high-frequency designs.
Features of High-Frequency Multilayer Design
Stack-Up Analysis
Layer Order:
Layer 1: Signal Layer
Layer 2: Ground Plane
Layer 3: Signal Layer
Layer 4: Power Plane
This stack-up reduces crosstalk and EMI, ensuring signal integrity.
The selected dielectric materials (4360 and 3006) provide low dielectric loss (Dk/Df), ensuring low delay and low attenuation for high-frequency signals.
Blind Via Design
The Drl3-4 blind via design connects only Layer 3 and Layer 4, shortening high-frequency signal paths and reducing parasitic inductance and capacitance, ensuring stable high-speed signal transmission.
The depth and diameter of blind vias are carefully controlled to meet electrical performance requirements.
Advantages of ENIG
The ENIG surface finish is ideal for high-frequency applications due to its low contact resistance, excellent oxidation resistance, and suitability for harsh environments.
Reason for No Solder Mask and Silkscreen
No Solder Mask: Removing the solder mask eliminates parasitic effects such as loss and reflection caused by the solder mask layer at high frequencies.
No Silkscreen: Silkscreen printing may cause minor signal discontinuities. Omitting silkscreen ensures higher signal integrity.
Considerations in High-Frequency PCB Design
Impedance Control
Impedance must be strictly controlled (typically 50Ω). The trace width is designed based on the material properties and signal frequency to ensure proper matching with the source and load, avoiding reflection and signal distortion.
Signal Integrity
Keep trace lengths short and direct to reduce signal delay and loss.
Avoid sharp right-angle turns; use rounded or 45° bends to minimize reflections.
Isolate critical high-frequency signals to prevent crosstalk.
Ground Plane Continuity
Ground planes must be complete and continuous to avoid breaks or segmentation.
Ensure short and direct return paths for signals.
Thermal Management
High-frequency circuits often generate significant heat. Use metal-based materials and optimize thermal designs to ensure board reliability.
Material Compatibility
Materials like 4360 and 3006 must provide stable dielectric constants and low loss tangent over the operating frequency range.
PP bonding materials must ensure strong adhesion between layers to prevent delamination.
By adhering to these design principles, the high-frequency 4-layer PCB ensures excellent electrical performance and reliability for advanced applications.