Strategies for Enhancing Multilayer Board Lamination Quality

B. Tailoring PP and CU Foil Configuration:

To meet PCB user requirements, precision in selecting Polypropylene (PP) and Copper (CU) foil configurations is crucial. PP specifications, including dielectric layer thickness, dielectric constant, characteristic impedance, withstand voltage, and laminate surface smoothness, must align with customer needs. Consider the following when choosing PP:

1. Resin Filling Capability: Ensures gaps in printed wires are filled during lamination.
2. Air and Volatile Matter Elimination: Fully removes air and volatile substances between laminations.
3. Dielectric Layer Thickness: Provides necessary thickness for the multilayer board.
4. Bonding Strength and Appearance: Ensures strong bonding and a smooth surface.

Recommended PP Configurations:

• For 4-layer laminates: 7628, 7630, or 7628+1080, 7628+2116.
• For >6 layers: Primarily 1080 or 2116, with 7628 for increased dielectric layer thickness.

CU Foil selection adheres to IPC standards and varies based on PCB user requirements.

C. Inner Core Board Processing Technology:

Inner core board treatment during multilayer board lamination involves black oxidation and browning processes.

1. Black Oxidation Treatment: Forms a black oxide film on the inner copper foil with a thickness of 0.25-4.50mg/cm2.
2. Browning Process (Horizontal Browning): Forms an organic film on the inner copper foil.

Functions of Treatment Process:

1. Enhances bonding force by increasing the contact surface between inner copper foil and resin.
2. Improves effective wettability of molten resin to copper foil, ensuring a strong grip after curing.
3. Prevents decomposition of curing agent dicyandiamide in liquid resin at high temperatures.
4. Enhances acid resistance during wet processes, preventing the occurrence of pink circles.

Implementing these strategies ensures the production of high-quality multilayer boards, meeting both technical and customer-specific requirements.