Flexible PCBs: Adhesive vs. Non-Adhesive

Flame retardant copper-clad phenolic paper laminate, specified under IPC4101 as number 02 with TgN/A, is commonly used in the production of flexible PCBs.

Classification

• Adhesive Flexible PCBs: These PCBs are cost-effective but may have lower flexibility and bonding strength compared to non-adhesive PCBs.
• Non-Adhesive PCBs: While more expensive, non-adhesive PCBs offer superior flexibility, bonding strength between copper foil and substrate, and pad flatness. They are ideal for applications requiring high pad flatness, such as COF (CHIPONFLEX).

Due to their higher cost, non-adhesive flexible PCBs are used in specialized applications, while adhesive flexible boards remain more common in the market. It’s essential to consider proper design and processing to prevent issues like micro-cracks and open solder joints, especially in bending applications.