Rogers high-frequency laminates, including RO4003C, RO4350B, and RO4835, are widely used in applications requiring superior electrical performance and mechanical stability. These materials are essential in RF, microwave, and high-speed digital designs. This guide provides detailed processing instructions to ensure optimal performance and reliability.

1. Material Overview:

• RO4003C: Glass-reinforced hydrocarbon ceramic material with processing similar to FR-4. Ideal for low-cost, high-frequency applications.
• RO4350B: Glass-reinforced hydrocarbon ceramic laminate with excellent dimensional stability and mechanical properties.
• RO4835: Enhanced oxidation-resistant laminate offering improved stability in harsh environments compared to RO4350B.

2. Lamination and Pressing:

• Press Temperature: 425°F – 475°F (218°C – 246°C)
• Pressure: 200 – 400 psi
• Heating Rate: 4°F – 6°F/min (2°C – 3°C/min)
• Cool Down Rate: ≤ 6°F/min under pressure (until laminate temperature drops below 150°F (65°C))
• Key Notes: Gradual cooling prevents warping and delamination. Release pressure only after the laminate reaches below 150°F (65°C).

3. Drilling:

• Drill Speed: 500 – 1000 SFM
• Retract Rate: 300 – 500 IPM
• Hit Count: 500 – 1000 hits per drill bit
• Backup Board: Rigid phenolic or aluminum entry boards reduce burrs and improve hole quality.
• Entry Board: Aluminum or thin phenolic boards are recommended to minimize drill wandering.

4. Hole Preparation (Desmear):

• Plasma Etch (Preferred):
  • Temperature: 250°C (482°F)
  • Time: 45 minutes
  • Gas Mix: Oxygen/nitrogen with CF4 (optional for enhanced cleaning)
• Chemical Desmear (Optional):
  • Mild permanganate solution or other oxidative treatments
  • Minimal dwell time to prevent material degradation

5. Copper Plating:

• Direct metallization or electroless copper is suitable.
• Avoid aggressive desmear or conditioning agents.
• Ensure thorough surface preparation to guarantee uniform plating.

6. Imaging and Etching:

• Photoresist: Compatible with standard dry-film or liquid photoresists.
• Etchant: Ammoniacal or peroxide-based etchants.
• Etching Control: Minimize side-etching to maintain pattern accuracy. Rinse thoroughly to avoid residual contamination.

7. Solder Mask and Surface Finish:

• Solder Mask: Liquid photoimageable (LPI) or screen printable solder masks are recommended.
• Bake Cycle: 300°F – 325°F (150°C – 163°C)
• Surface Finishes:
  • Electroless Nickel Immersion Gold (ENIG)
  • Immersion Tin or Silver
  • Organic Solderability Preservative (OSP)

8. Soldering and Assembly:

• Lead-Free Compatibility: Yes
• Peak Reflow Temperature: Up to 260°C (500°F)
• Cool Down Rate: ≤ 6°C/min to avoid warping or delamination.
• Key Notes: Avoid excessive reflow cycles to minimize material stress.

9. Mechanical Processing:

• Routing and Milling: Carbide tools with low feed rates prevent material cracking.
• Edge Finishing: Sand lightly to remove burrs without damaging copper layers.
• V-Scoring: Maintain a low angle to reduce the risk of delamination.

10. Key Considerations:

• Store materials in a dry, temperature-controlled environment to prevent moisture absorption.
• Regularly inspect and maintain drill bits to ensure clean hole formation.
• Test final boards for electrical performance, thermal cycling, and mechanical stress.

By following these guidelines, manufacturers can ensure high-yield, reliable production of RF and microwave PCBs using Rogers laminates.