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How Copper Clad Laminate (CCL) Is Manufactured – Credisyn

Understanding the Components of CCL

1. Reinforcement: Glass Fabric

• Styles:
  
  • 7628 Style: A heavier weave for thicker cores.
  • 1080/2116 Styles: Finer weaves for thinner dielectrics, enhancing laser drilling precision.
• Surface Treatment: The glass filaments receive a silane coupling treatment, ensuring effective bonding with the resin and preventing issues like delamination.

2. The Matrix: Resin System

• Base Polymer: Epoxy resin.
• Curing Agents: Chemicals that react with the epoxy to create cross-linked networks.
• Fillers: These adjust properties like the Coefficient of Thermal Expansion (CTE) and improve flame retardancy.
• Solvents: Chemicals that facilitate the resin’s penetration into glass cloth.

3. Conductor: Copper Foil

• Electro-Deposited (ED) Copper: Produced by plating copper onto a titanium drum.
• Tooth Profile: The matte side of the copper is treated to create a rough texture, which enhances resin adhesion. For high-frequency applications, we use Very Low Profile (VLP) or HVLP copper to minimize signal loss.

Step-by-Step Manufacturing Process

1. Dissolution: Solid epoxy resins are dissolved in solvents in controlled mixing tanks.
2. Blending: Hardiners and fillers are incorporated.
3. Viscosity Control: Continuous monitoring ensures optimal viscosity, crucial for proper impregnation into glass fibers.

1. Dip Coating: The glass cloth is immersed in resin varnish.
2. Squeeze Rolls: Precision measurement of resin content (RC%) as the wet cloth exits.
3. Drying: The cloth moves into an oven to remove solvents, achieving a semi-cured B-Stage state, still soft enough to melt upon reheating.

1. Clean Room Assembly: In a sanitized environment, stainless steel plates, copper foil, and prepreg sheets are stacked.
2. Automation: Robotic arms ensure precise assembly to minimize contamination.

1. Vacuum Draw: Air is evacuated to eliminate trapped gases.
2. Heating: The temperature rises to melt the B-Stage resin.
3. Pressure Application: Hydraulic presses apply significant force (300–400 psi) to ensure uniformity and high-density bonding.
4. Curing: The material is held at temperature to fully cross-link the resin, solidifying the laminate.
5. Controlled Cooling: Gradual cooling maintains dimensional integrity, preventing warpage.

1. Disassembly: The stack is removed from the press.
2. Trimming and Cleaning: Edges are trimmed, and surfaces are cleaned of contaminants.

Quality Control Measures

• Automated Optical Inspection (AOI): Scans for surface defects.
• Thermal Stress Testing: Measures resistance to thermal shock.
• Peel Strength Testing: Assesses adhesion between copper and resin.
• Electrical Testing: Measures dielectric breakdown and impedance.

Variations in Production: Beyond Standard FR-4

1. Aluminum-Based CCL (IMS): For enhanced thermal management, featuring aluminum cores.
2. High-Frequency Laminates: Utilizing PTFE for 5G applications, requiring specialized processing parameters.
3. Halogen-Free Materials: Eco-friendly options that meet stringent environmental regulations.

The Future of CCL Manufacturing

• Slot Die Coating: Allows for precise resin thickness control within 1 micron.
• Continuous Lamination: Increases efficiency and consistency.
• AI-Driven Process Control: Implementing AI technologies for predictive analytics in manufacturing processes.

Conclusion: The Credisyn Commitment to Quality

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