A process for surface texturing of Kapton polyimide to improve adhesion to metals

The authors have discovered that polyimide undergoes a surface texturing process when seeded with a thin layer of copper and subjected to a high-temperature (above 400°C) treatment in air. During this heating process, copper undergoes a clustering and migration process and initiates a copper-catalyzed degradation localized around the vicinity of the cluster particles to impart a textured surface. Subsequent metallization of the textured surface leads to improved adhesion, predominantly due to mechanical anchoring. Adhesion values of 7-10 lbs/in (ambient) and 4-6 lbs/in (after solder float test) have been obtained. High retention of adhesion under 85°C/85% relative humidity and 150°C aging is obtained when textured Kapton is seeded with palladium and plated with electroless nickel