Investigation of improved adhesion between Cu film and polyimide by the PSII-EIAMAD technique

Abstract

Plasma source ion implantation (PSII) is a relatively simple and effective ion implantation/deposition technique for the surface modification of materials. In PSII, a substrate is immersed in the plasma, and negative, high-voltage pulses are applied to accelerate ions into the substrate in order to modify the surface properties of materials. PSII technique combined with energetic ion-assisted mixing and deposition (EIAMAD) was used to improve the adhesion between the Cu film and polyimide. Cu films processed with ion-assisted mixing showed higher adhesion strength than that of not processed or plasma-cleaned ones. Cu films on polyimide substrate were deposited by using different ion species to investigate the ion effect on the interface mixing. Argon ion bombardment led to more adhesive and gradient layers as a function of ion energy and ion dose. The adhesion strength was determined by the 90 degrees peel test. The characterization of Cu-deposited polyimide, generated with ion-assisted mixing by PSII, was performed by AES, SEM, and AFM. Our results suggested that PSII-EIAMAD was a very useful method to grow Cu films with good adhesion properties on polyimide at room temperature. Copyright (C) 2006 John Wiley & Sons, Ltd.