Rapid treatment of polyimide film surfaces using high-density microwave plasma for enhancement of Cu layer adhesion

A high-density microwave plasma has been applied to the surface of polyimide (PI) films as a treatment to enhance the adhesion of sputter-deposited copper layers. A very short (similar to 5 s) exposure to At plasma enhanced the contact angle from 72 degrees to similar to 14 degrees. X-ray photoelectron spectroscopy and atomic force microprobe measurements showed an increase in hydrophilic radicals (-OH, -C=O) and surface roughness, respectively, following the plasma treatment. Peel strength tests of Cu layers deposited on plasma-treated polyimide films showed that the plasma treatment significantly enhanced Cu layer adhesion. (C) 2008 Elsevier Ltd. All rights reserved